Compressed Air Systems
Remade for neutrality: every choice explained, project facts as parameters, scope boundaries linked both ways
Showing changes from Rev 2
to Rev 3
in Compressed Air Systems.
---
title: Compressed Air Systems
category: Plumbing
−toc_depth: 3
description: >
− When to use: General-service compressed air systems serving shop, laboratory,
− light-industrial, institutional, healthcare-support, and government facilities,
− covering the complete system from compressor through receiver, air treatment
− (aftercoolers, dryers, filters, separators), distribution piping, and terminal
− outlets, up to 200 psig typical facility service, including lubricated and
− oil-free, single and duplex configurations, and instrument- and shop-quality tiers.
− Not intended for: medical and dental air piped to patient care areas under NFPA 99
− Level 1 (use [[sync/medical-gas-systems]]); natural gas, propane, and other fuel
− gas (use [[sync/natural-gas-piping]] and [[sync/fuel-gas-piping]]); air-driven and
− non-air specialty outlets (use [[sync/plumbing-specialties]]); HVAC pneumatic
− controls integrated into building automation (use [[sync/hvac-controls-instrumentation]]);
− process piping over 200 psig or classified ASME B31.3 process service; and breathing
− air for SCBA or respiratory protection under OSHA Grade D.
+ When to use: Facility compressed air systems that generate, condition, store, and distribute general-service air at facility pressures for pneumatic tools, actuators, blow-off and cleaning stations, laboratory apparatus, instrument and pneumatic control loops, pulse-jet filter cleaning, and the supervisory air supply of sprinkler systems where one plant serves more than the sprinklers. Covers the decisions that define such a system: the ISO 8573-1 air quality class for each contaminant, compressor type, lubrication, cooling, capacity control and redundancy, aftercooling and separation, dryer type and arrangement, filtration, receivers, condensate drains and oil-water separation, distribution piping material, joining, sizing and configuration, drops and outlets, controls and monitoring, pressure and leak testing, purity verification, startup, warranty, and spares, in new construction and in expansion of an existing system.
+ Not intended for: Medical air, dental air, and instrument air serving patient care under NFPA 99, which have their own source equipment, alarms, and verification ([[sync/medical-gas-systems]]); the branch tubing and devices of a pneumatic control system, which begin at the branch that serves a control device ([[sync/hvac-controls-instrumentation]]); a compressor dedicated to a dry-pipe, pre-action, or deluge sprinkler system and the air maintenance device at every sprinkler connection ([[sync/dry-pipe-fire-sprinkler-systems]] and [[sync/pre-action-and-deluge-sprinkler-systems]]); natural gas, propane, and other fuel gas piping ([[sync/natural-gas-piping]] and [[sync/fuel-gas-piping]]); breathing air for respirators under OSHA 29 CFR 1910.134, which is not covered by this standard; dental office air systems below the NFPA 99 category thresholds, laboratory specialty gases, and vacuum systems, which are not covered by this standard; and process air systems above 200 psig or designed as part of a process unit, whose vessels, piping, and tests are outside the facility-service provisions written here.
---
# Scope {toc}
−## This standard covers general-service compressed air systems for shop, laboratory, light-industrial, institutional, healthcare-support, and government facility applications. {note}
+## This standard covers the complete facility compressed air system from the compressor intake to the terminal outlet: the compressors and their motors, starters, and controllers; the aftercooler and separator; the dryer and filters; the receivers; the condensate drains and oil-water separator; the distribution mains, branches, drops, and outlets; the monitoring and alarms; and the tests that prove the installed system delivers the air quality, pressure, and capacity it was designed for. {note}
−## General-service compressed air is the utility air that powers pneumatic tools, actuators, laboratory apparatus, blow-off and cleaning stations, and instrument loops throughout a facility. It is generated by one or more compressors, conditioned by a treatment train, accumulated in a receiver, and distributed through fixed piping to terminal outlets. This standard addresses the complete system as a coordinated assembly rather than as isolated pieces of equipment, because the air quality delivered at any outlet is the product of every upstream component working together. {note}
+## The air delivered at an outlet is the product of every component upstream of it. A compressor specified alone leaves the water, oil, and particle content of the air, the storage that steadies its pressure, and the piping that carries it undefined, and those are the parts of a compressed air system that fail in service. This standard treats the system as one assembly so that the purity class, the pressure, and the capacity hold at the point of use. {note}
−## The system shall be furnished complete from compressor intake through terminal outlets, including air treatment, receiver, distribution piping, condensate management, and controls.
+## The system shall be furnished complete and operable from the compressor intake through the terminal outlets, including every component named in this standard whether or not it is shown individually on the drawings.
−## A compressed air package specified only as a compressor leaves the air quality, storage, and distribution undefined, which is the most common source of underperforming installations. Treating the system as a whole is what lets the engineer hold a purity class at the point of use. {note}
+## The services the system supplies shall be as indicated in the datasheet.
−## This standard applies to new construction and to expansions of existing compressed air systems. {note}
+```datasheet
+label: Services Supplied by the System
+type: checkbox
+options:
+ - "Shop and pneumatic tool air"
+ - "Blow-off and cleaning stations"
+ - "Laboratory bench air"
+ - "Instrument and pneumatic control air"
+ - "Process and machine air"
+ - "Pulse-jet filter cleaning air"
+ - "Sprinkler system supervisory air"
+default:
+ - "Shop and pneumatic tool air"
+```
−## This standard applies to systems operating at pressures up to 200 psig typical facility service. {note}
+## The services the system supplies fix the air quality it has to deliver and the consequence of losing it. Shop air tolerates water and oil that would foul an instrument, a dust collector valve, or a laboratory sample; a sprinkler supervisory supply has to stay in service through a plant shutdown that the shop air can ride out. The most demanding service governs the air quality class and the redundancy basis for the whole system unless that service is given its own header under this standard. {note}
−## General-service headers operate at 90 to 125 psig; specialty high-pressure headers may reach 200 psig. Pressures above 150 psig, or piping located in process-classified areas, shift the governing piping code from ASME B31.1 to ASME B31.3 and are addressed accordingly within this standard. {note}
+## The number of compressors, the rated capacity of each, the header operating pressure, and the receiver volume shall be as indicated on [[drawing: the compressed air equipment schedule on the plumbing drawings]].
−## Medical air and dental air piped to patient care areas under NFPA 99 Level 1 are excluded and are governed by [[sync/medical-gas-systems]]. {note}
+## The routing of mains and branches, the extent of each pressure zone, the location of each pressure-reducing station, and the location of each drop and outlet shall be as indicated on [[drawing: the compressed air piping plans and riser diagram]].
−## Level 1 medical air is a life-safety system with its own source equipment, alarms, certification, and dedicated piping. It must never share source equipment or distribution with general-service air. {note}
+## The system boundary against other standards is as follows. {note}
−## Breathing air for respiratory protection (OSHA 29 CFR 1910.134 Grade D) is excluded; it is a distinct safety classification with its own purity, monitoring, and alarm requirements. {note}
+- The compressor, dryer, receiver, and main distribution of a control air system are furnished under this standard, and [[sync/hvac-controls-instrumentation]] begins at the branch that serves a control device
+- Where the same compressors serve a dry-pipe, pre-action, or deluge sprinkler riser together with other services, the compressors, the treatment, and the branch to each riser are furnished under this standard, while the air maintenance device, the check valve, and everything downstream of them are governed by [[sync/dry-pipe-fire-sprinkler-systems]] or [[sync/pre-action-and-deluge-sprinkler-systems]], as is a compressor dedicated to the sprinklers alone
+- Compressed air distribution piping is furnished under this standard and not under [[sync/fuel-gas-piping]], which excludes it
+- Pulse-jet cleaning air is delivered by this standard to the collector; the regulation, dew point, and pulse pressure at the collector are governed by [[sync/dust-and-fume-collection]]
+- General-purpose compressed air for shop and pneumatic tools in a healthcare facility is furnished under this standard, and medical air, dental air, and instrument air serving patient care are furnished under [[sync/medical-gas-systems]]
−## Fuel gas, natural gas, propane, process piping above 200 psig, and air-driven specialty outlets are excluded and are covered by their respective standards. {note}
+## The following are not covered by this standard. {note}
−## See [[sync/natural-gas-piping]], [[sync/fuel-gas-piping]], and [[sync/plumbing-specialties]]. Pneumatic HVAC controls tied into the building automation system are covered by [[sync/hvac-controls-instrumentation]]. {note}
+- Breathing air for respiratory protection under OSHA 29 CFR 1910.134, which has its own Grade D purity, carbon monoxide monitoring, and alarm requirements and is not owned by any standard in this library
+- Dental office air systems below the NFPA 99 category thresholds, laboratory specialty gases, and shop or laboratory vacuum systems, which are not owned by any standard in this library
+- Natural gas, propane, and other fuel gas, which are governed by [[sync/natural-gas-piping]] and [[sync/fuel-gas-piping]]
+- Process air systems operating above 200 psig or designed as part of a process unit, because the receivers, piping materials, joining methods, and test provisions in this standard are written for facility service, and a high-pressure or process system is designed under ASME B31.3 and ASME BPVC Section VIII by the process engineer responsible for that unit
# Referenced Standards {toc}
…5 unchanged lines
| Standard | Title |
|----------|-------|
−| ANSI/CAGI B19.1 | Safety Standard for Air Compressor Systems |
−| ASME B19.3 | Safety Standard for Compressor Inlets |
−| ASME BPVC Section VIII, Div. 1 | Rules for Construction of Pressure Vessels |
+| ANSI/CAGI B19.1 | Safety Standard for Compressor Systems |
+| ASME BPVC Section VIII, Division 1 | Rules for Construction of Pressure Vessels |
+| ASME BPVC Section IX | Welding, Brazing, and Fusing Qualifications |
+| ASME B31.9 | Building Services Piping |
| ASME B31.1 | Power Piping |
| ASME B31.3 | Process Piping |
+| ASME B16.3 | Malleable Iron Threaded Fittings |
+| ASME B16.9 | Factory-Made Wrought Buttwelding Fittings |
+| ASME B16.11 | Forged Fittings, Socket-Welding and Threaded |
+| ASME B16.22 | Wrought Copper and Copper Alloy Solder-Joint Pressure Fittings |
+| ASTM A53/A53M | Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and Seamless |
+| ASTM A312/A312M | Seamless, Welded, and Heavily Cold Worked Austenitic Stainless Steel Pipes |
+| ASTM B88 | Seamless Copper Water Tube |
+| AWS A5.8/A5.8M | Filler Metals for Brazing and Braze Welding |
| ISO 8573-1 | Compressed Air, Part 1: Contaminants and Purity Classes |
−| ISO 8573-2 through 8573-9 | Compressed Air, Test Methods for Contaminant Measurement |
−| NFPA 99 | Health Care Facilities Code |
+| ISO 8573-2 through ISO 8573-9 | Compressed Air, Test Methods for Contaminants |
+| ISO 1217 | Displacement Compressors: Acceptance Tests |
+| ISO 7183 | Compressed-Air Dryers: Specifications and Testing |
+| ISO 12500 | Filters for Compressed Air: Test Methods |
+| ISO 2151 | Acoustics: Noise Test Code for Compressors and Vacuum Pumps |
+| ANSI/ISA-7.0.01 | Quality Standard for Instrument Air |
+| NEMA MG 1 | Motors and Generators |
+| NEMA 250 | Enclosures for Electrical Equipment (1000 Volts Maximum) |
+| UL 508A | Industrial Control Panels |
| NFPA 70 | National Electrical Code (Article 430) |
+| NFPA 99 | Health Care Facilities Code |
| OSHA 29 CFR 1910.169 | Air Receivers |
−| OSHA 29 CFR 1910.134 | Respiratory Protection, Grade D Breathing Air |
−| UFC 3-420-02 | Unified Facilities Criteria: Compressed Air |
−| ASHRAE 15 | Safety Standard for Refrigeration Systems |
−| ASTM A53/A53M | Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and Seamless |
−| ASTM B88 | Seamless Copper Water Tube |
+| OSHA 29 CFR 1910.242 | Hand and Portable Powered Tools and Equipment, General |
+| OSHA 29 CFR 1910.95 | Occupational Noise Exposure |
+| UFC 3-420-02 | Compressed Air |
−## ANSI/CAGI B19.1 governs compressor system safety (controls, guarding, relief sizing) while ASME BPVC Section VIII governs the pressure vessel; the two are complementary and both apply. {note}
+## ANSI/CAGI B19.1 governs the compressor package as a machine, including guarding, relief devices, and controls, while ASME BPVC Section VIII governs the receiver as a pressure vessel; both apply, and neither covers the other's subject. {note}
−## ISO 8573-1 is referenced for purity classification; the latest adopted edition applies, as the standard has been under revision. {note}
+## ISO 8573-1 defines the purity classes by which every air quality requirement in this standard is stated, and the parts of ISO 8573 that follow it define the test methods by which a class is verified. The class designation is written as three numbers in the order particles, water, oil, so that 2.4.2 means particle Class 2, water Class 4, and oil Class 2. {note}
# Submittals {toc}
−## The Contractor shall submit the following action submittals for review before fabrication or ordering:
−- Product data for each compressor, dryer, filter, separator, receiver, and condensate device, including capacity, power, and noise data
−- Shop drawings showing compressor room layout, equipment clearances, piping arrangement, and connection points
−- Receiver tank ASME data report and nameplate information showing MAWP and code stamp
−- Air purity calculation demonstrating the delivered ISO 8573-1 class at each point of use
−- Pipe sizing calculation demonstrating total distribution pressure drop within the specified limit
−- Electrical coordination data: motor full-load amperes, locked-rotor amperes, and starting method
+## Action Submittals {toc}
+### The Contractor shall submit the following for the Engineer of Record's review and return before any compressor, dryer, receiver, or distribution piping is procured:
+
+- Product data for each compressor package, identifying the type, lubrication, number of stages, cooling, drive, capacity control, rated capacity and full-load discharge pressure on the CAGI performance data sheet, motor nameplate data, starter and controller, sound pressure level, and the package relief valve setting
+- Product data for the aftercooler and separator, the dryer, and each filter, identifying the rated capacity at the standard rating conditions and the correction to the project inlet temperature, pressure, and ambient, the outlet pressure dew point, the pressure drop at rated flow, and the ISO 12500 performance basis of each filter element
+- Product data for each receiver, identifying the volume, orientation, interior protection, MAWP, design temperature, relief valve capacity and setting, and the ASME data report
+- Product data for each condensate drain and the oil-water separator, identifying the drain type, the separator capacity, and the oil concentration the separator discharge is rated to
+- A purity statement showing the ISO 8573-1 class delivered at the outlet of the treatment train and at each outlet class indicated in the datasheet, with the component that achieves each contaminant class
+- A pipe sizing calculation showing the design flow, the pipe size and velocity in each main and branch, and the pressure drop from the treatment train outlet to the hydraulically farthest outlet at the design flow
+- Shop drawings of the compressor room showing equipment, service clearances, intake and heat rejection paths, piping, drains, and electrical connections
+- Product data for the distribution piping, fittings, joints, valves, drops, outlets, and couplers, identifying the pressure and temperature rating of each and, for a modular system, the manufacturer's rating of the system for compressed air service
+- Electrical coordination data for each motor, identifying the full-load current, locked-rotor current or inrush under the starting method, and the branch circuit and disconnect required under NFPA 70 Article 430
+
```datasheet
−label: Action submittals required
+label: Action Submittals Required
type: checkbox
options:
− - Product data (compressor, dryer, filter, separator, receiver)
− - Shop drawings (room layout, clearances, piping)
− - Receiver ASME data report and nameplate
− - Air purity calculation per use point
− - Pipe sizing / pressure-drop calculation
− - Electrical coordination data (FLA, LRA, starting method)
+ - "Compressor package product data with CAGI data sheet"
+ - "Air treatment product data"
+ - "Receiver product data and ASME data report"
+ - "Condensate drain and oil-water separator product data"
+ - "Purity statement by outlet class"
+ - "Pipe sizing calculation"
+ - "Compressor room shop drawings"
+ - "Distribution piping and outlet product data"
+ - "Electrical coordination data"
+default:
+ - "Compressor package product data with CAGI data sheet"
+ - "Air treatment product data"
+ - "Receiver product data and ASME data report"
+ - "Condensate drain and oil-water separator product data"
+ - "Purity statement by outlet class"
+ - "Pipe sizing calculation"
+ - "Compressor room shop drawings"
+ - "Distribution piping and outlet product data"
+ - "Electrical coordination data"
```
−## The Contractor shall submit the following closeout submittals before substantial completion:
−- Operation and maintenance manuals for all equipment
−- Manufacturer warranty documentation
−- Record drawings of installed piping and equipment
−- Test and certification reports, including receiver relief valve, leak test, and dew point verification
−- Startup and commissioning report
+### The purity statement is where a mismatch between the compressor and the air quality class is caught before it is bought. A lubricated compressor submitted against an oil Class 0 requirement, or a refrigerated dryer submitted against a water Class 2 requirement, cannot be corrected by anything downstream of the purchase. {note}
+## Informational Submittals {toc}
+
+### The Contractor shall submit the following before the work they concern begins:
+
+- The oil concentration limit and any other condensate discharge limit of the authority that receives the discharge, confirmed in writing by that authority
+- Welder performance qualifications and the welding procedure specifications for welded steel or stainless steel piping, qualified under ASME BPVC Section IX
+- The manufacturer's installation instructions for each compressor, dryer, receiver, and modular piping system
+- The pressure test plan, identifying the test medium, test pressure, hold time, the sections to be tested, and the components to be isolated from the test
+
```datasheet
−label: Closeout submittals required
+label: Informational Submittals Required
type: checkbox
options:
− - Operation and maintenance manuals
− - Warranty documentation
− - Record drawings
− - Test and certification reports
− - Startup and commissioning report
+ - "Condensate discharge limits of the receiving authority"
+ - "Welder qualifications and welding procedures"
+ - "Manufacturer's installation instructions"
+ - "Pressure test plan"
+default:
+ - "Condensate discharge limits of the receiving authority"
+ - "Welder qualifications and welding procedures"
+ - "Manufacturer's installation instructions"
+ - "Pressure test plan"
```
−## The Contractor shall submit the following informational submittals:
−- Manufacturer installation instructions for each major component
−- Welder qualifications and weld procedure specifications where applicable
−- Confirmation of local sewer authority condensate discharge limits
+## Closeout Submittals {toc}
+### The Contractor shall submit the following before the system is accepted:
+
+- Pressure test records for each section tested, recording the test medium, pressure, hold time, ambient temperature, and result
+- The leakage test record, recording the method, the measured leakage rate, and its ratio to the installed capacity
+- The startup report of the manufacturer's representative for each compressor and dryer, recording the as-left control settings, the measured discharge pressure and temperature, the measured outlet pressure dew point, and the motor current under load
+- The purity verification record for each contaminant class tested, identifying the ISO 8573 test method, the sample point, and the result
+- The receiver relief valve certification and the receiver's National Board registration where the vessel is registered
+- Operation and maintenance data covering each compressor, dryer, filter, drain, separator, and modular piping system, the sequencing settings, the filter and lubricant change intervals, and the drain and separator service procedure
+- As-built drawings recording the installed routing, valve locations, outlet locations, and pressure zones
+- The training record identifying the attendees, the date, and the subjects covered
+
```datasheet
−label: Informational submittals required
+label: Closeout Submittals Required
type: checkbox
options:
− - Manufacturer installation instructions
− - Welder qualifications / weld procedures
− - Sewer authority condensate discharge limits
+ - "Pressure test records"
+ - "Leakage test record"
+ - "Manufacturer's startup report"
+ - "Purity verification record"
+ - "Receiver relief valve certification and registration"
+ - "Operation and maintenance data"
+ - "As-built drawings"
+ - "Training record"
+default:
+ - "Pressure test records"
+ - "Leakage test record"
+ - "Manufacturer's startup report"
+ - "Purity verification record"
+ - "Receiver relief valve certification and registration"
+ - "Operation and maintenance data"
+ - "As-built drawings"
+ - "Training record"
```
# Quality Assurance {toc}
−## The compressor manufacturer shall be regularly engaged in the production of facility compressed air equipment.
+## Each compressor package shall be the product of a manufacturer that has produced compressors of the type furnished for not less than five years and that maintains a service organization able to reach the site within one working day.
−## The compressor manufacturer shall demonstrate a minimum of five years of production of the specified compressor type.
+## Where the parties disagree whether a manufacturer meets that requirement, the Engineer of Record shall make the initial determination.
−## Air receivers shall be constructed, inspected, and stamped in accordance with ASME BPVC Section VIII, Division 1.
+## The compressor package, including its guarding, relief devices, and controls, shall comply with ANSI/CAGI B19.1.
−## OSHA 29 CFR 1910.169 makes ASME compliance a federal requirement for air receivers, and any receiver of 1.5 cubic feet or larger operating above 15 psig must carry the ASME code stamp. {note}
+## The rated capacity and specific power of each compressor shall be stated on the CAGI performance data sheet for the compressor type, tested in accordance with ISO 1217.
−## Welding of steel distribution piping shall be performed by welders qualified under ASME Section IX to the applicable weld procedure specification.
+## The CAGI data sheet is the one document on which compressor capacity is stated at a common set of conditions and by a common test, so that two bids can be compared. A capacity stated without it is stated at whatever inlet condition the manufacturer chose. {note}
−## The compressor and accessories shall comply with ANSI/CAGI B19.1 for safety, guarding, and relief device sizing.
+## The dryer shall be rated in accordance with ISO 7183 or the CAGI standard rating conditions for the dryer type, and the rating shall be corrected to the project inlet temperature, inlet pressure, and ambient temperature in the submittal.
−## Compressor inlets shall be guarded in accordance with ASME B19.3.
+## Each receiver shall be constructed, inspected, and stamped in accordance with ASME BPVC Section VIII, Division 1, and shall comply with OSHA 29 CFR 1910.169.
−# Environmental and Service Conditions {toc}
+## Welding of steel and stainless steel distribution piping shall be performed by welders qualified under ASME BPVC Section IX to the welding procedure specification submitted.
−## The compressor room ambient temperature shall not exceed 100°F (38°C) under any operating condition.
+## The compressor controller, the starter, and any system controller shall be listed under UL 508A or furnished as part of a listed compressor package.
−## Rotary screw and reciprocating compressors derate and the discharge air carries more moisture as inlet and ambient temperature rise. Holding the room below 100°F preserves capacity and keeps the downstream dryer load within its rating. {note}
+## Modular aluminum, polyethylene, and other proprietary piping systems shall be rated by their manufacturer for compressed air service at the design pressure and the maximum operating temperature at the point of installation, and the rating shall be stated in the submittal.
−## Compressor room ventilation shall be provided at a minimum of 1 CFM of room ventilation per 1 CFM of compressor rated intake.
+# Service Conditions {toc}
−## This guidance follows UFC 3-420-02 and removes both the heat of compression rejected to the room and any heat from air-cooled aftercoolers. {note}
+## Compressor Room {toc}
−## The intended installation environment shall be identified so that dryer dew point and piping material are selected for the worst-case exposure.
+### The compressor room shall be ventilated or the package heat shall be ducted so that the room temperature does not exceed the maximum ambient temperature for which the compressors and the dryer are rated, with the outdoor air at [[parameter: site-ambient-temperature-maximum]].
+### Every horsepower of compressor input leaves the room as heat, either through the package cooler or through the aftercooler, and a compressor and a refrigerated dryer in a room that runs above their rated ambient lose capacity, raise the discharge temperature that the dryer has to remove, and trip on high temperature on the hottest day of the year, which is the day the plant is also at its highest demand. {note}
+
+### The path by which compressor package heat is rejected shall be as indicated in the datasheet.
+
```datasheet
−label: Compressor and distribution environment
+label: Compressor Package Heat Rejection
type: radio
options:
− - Indoor, conditioned compressor room; distribution in heated space
− - Indoor compressor room; distribution through unheated or intermittently heated space
− - Outdoor or freeze-exposed compressor and/or distribution
−default: Indoor, conditioned compressor room; distribution in heated space
+ - "Compressor room ventilation"
+ - "Ducted exhaust from the package cooler to outdoors"
+ - "Heat recovery to building heating with relief to outdoors"
+default: "Compressor room ventilation"
```
−## Where any portion of the distribution passes through unheated, outdoor, or freeze-exposed space, a desiccant dryer delivering the specified pressure dew point shall be provided.
+### Room ventilation handles the heat with a fan and a louver sized for it and leaves the package untouched; ducted exhaust takes the hot air directly outdoors and holds the room cooler for the same fan energy, at the cost of a duct the package cooler has to be able to push against; heat recovery puts the heat of compression into the building in winter and needs a damper and a relief path in summer. {note}
−## A refrigerated dryer holding a 35°F to 39°F pressure dew point is adequate only where every foot of pipe stays above freezing. Routing 35°F-dew-point air through an unheated space condenses and then freezes water in the line, blocking flow and damaging tools, which is one of the most common field failures. {note}
+### Where the package cooler discharge is ducted, the duct pressure drop shall not exceed the external static pressure the compressor manufacturer publishes for the package cooler fan.
−## Equipment and piping shall be anchored to resist seismic loads in accordance with the applicable building code where the project is located in a seismic design category that requires it.
+### The compressor room shall be maintained above 40°F (4°C) whenever the system is in service.
+### The compressor intake source shall be as indicated in the datasheet.
+
```datasheet
−label: Seismic anchorage required
+label: Compressor Intake Source
type: radio
options:
− - "Yes, per applicable building code seismic design category"
− - "No, low seismic design category"
−default: "No, low seismic design category"
+ - "Room air through the package intake filter"
+ - "Outdoor air ducted to the package intake"
+default: "Room air through the package intake filter"
```
−# Compressor {toc}
+### Room air is at the room temperature and carries the room's dust; outdoor air is cooler in summer, which raises capacity and lowers the moisture load per cubic foot delivered, and in winter is colder than an oil-injected compressor is designed to take in without a thermostatic intake provision. {note}
−## The compressor type shall be selected to match the facility duty cycle, required air quality, and maximum operating pressure.
+### Ducted intake air shall be filtered at the package, and the intake duct pressure drop shall not exceed the value the compressor manufacturer publishes for the intake.
−## For general facility service (shops, maintenance, light laboratory) the lubricated rotary screw with a refrigerated dryer is the most common selection: it offers continuous-duty capability, good efficiency, and the lowest installed cost for its capacity. Oil-free machines carry a significant cost premium and are justified only where the application genuinely cannot tolerate any oil carryover. Reciprocating machines remain economical for intermittent-duty shops at lower first cost. {note}
+### Compressor capacity, motor rating, and dryer capacity shall be corrected for [[parameter: altitude]] in accordance with the manufacturer's published correction factors.
−## The compressor type and lubrication class shall be as scheduled.
+### A compressor at altitude takes in thinner air and delivers less mass of air per revolution, the motor cooling fan moves less mass of air across the windings, and the dryer sees a smaller absolute pressure for the same gauge pressure, so each component is rated for a sea-level condition that the site does not provide. {note}
+## Freeze Exposure {toc}
+
+### Where any part of the distribution piping is routed outdoors or through space that is not heated, the pressure dew point of the air at the dryer outlet shall be below [[parameter: site-ambient-temperature-minimum]].
+
+### Air at the pressure dew point of a refrigerated dryer holds water that condenses the moment the pipe drops below that temperature, and in an unheated run it freezes where it condenses and closes the pipe from the inside. The dew point has to be below the coldest pipe wall the air passes over, not the coldest room the compressor sits in. {note}
+
+### Outdoor and unheated runs of distribution piping shall be pitched to a drip leg in heated space or to a drain that can be operated from heated space.
+
+## Seismic Restraint and Classified Locations {toc}
+
+### Anchorage of compressors, dryers, and receivers and restraint of the distribution piping shall be as required by [[sync/vibration-isolation-and-seismic-restraint]] for [[parameter: seismic-design-category]].
+
+### Electrical equipment of the system installed in a location classified under NFPA 70 Article 500 shall be rated for the classification indicated on [[drawing: the electrical drawings]].
+
+# Air Quality {toc}
+
+## The air quality delivered at the outlet of the treatment train shall be the ISO 8573-1 class for each contaminant indicated in the datasheet.
+
```datasheet
−label: Compressor type
+label: ISO 8573-1 Particle Class at the Treatment Train Outlet
type: select
+derived: "the most demanding service indicated in the datasheet, applied to the purity classes of ISO 8573-1"
options:
− - Lubricated rotary screw
− - Oil-free rotary screw
− - Lubricated reciprocating
− - Oil-free reciprocating
− - Scroll (oil-free)
− - Centrifugal
−default: Lubricated rotary screw
+ - "Class 1"
+ - "Class 2"
+ - "Class 3"
+ - "Class 4"
+ - "Class 5"
+ - "Class 6"
+default: derived
```
−## Where an oil-free air purity class is required at any point of use, an oil-free compressor shall be provided.
+```datasheet
+label: ISO 8573-1 Water Class at the Treatment Train Outlet
+type: select
+derived: "the most demanding service indicated in the datasheet and the coldest pipe wall the air passes over, applied to the purity classes of ISO 8573-1"
+options:
+ - "Class 1"
+ - "Class 2"
+ - "Class 3"
+ - "Class 4"
+ - "Class 5"
+ - "Class 6"
+default: derived
+```
−## Filtered oil-lubricated machines cannot reliably reach ISO 8573-1 Class 1 oil because oil aerosol and vapor pass through coalescing filters as their efficiency degrades. Specifying a Class 1 oil requirement while scheduling a lubricated machine generates substitution requests and field disputes. The purity requirement and the compressor selection must agree. {note}
+```datasheet
+label: ISO 8573-1 Oil Class at the Treatment Train Outlet
+type: select
+derived: "the most demanding service indicated in the datasheet, applied to the purity classes of ISO 8573-1"
+options:
+ - "Class 0"
+ - "Class 1"
+ - "Class 2"
+ - "Class 3"
+ - "Class 4"
+default: derived
+```
−## The compressor arrangement shall provide the redundancy and turndown the facility requires.
+## Each class number in ISO 8573-1 is a limit on one contaminant, and a lower number is a tighter limit. The water class is a pressure dew point: Class 4 corresponds to +3°C (37°F), which is what a refrigerated dryer delivers; Class 3 to −20°C (−4°F); Class 2 to −40°C (−40°F), which is what a desiccant dryer delivers; and Class 1 to −70°C (−94°F). The oil class is a total oil content by aerosol, liquid, and vapor, with Class 1 at 0.01 mg/m³ and Class 2 at 0.1 mg/m³; Class 0 is not a fixed number but a limit tighter than Class 1 that the user and the supplier agree on and write down. The particle class limits the count of particles in three size bands, and Class 2 is in the range a high-efficiency coalescing filter delivers. {note}
+## The classes are chosen one contaminant at a time, and each one is bought with a different component. A shop air system commonly runs at a class in the range of 3.4.3 or 2.4.2 on a refrigerated dryer and a coalescing filter; an instrument air header needs the water class that keeps the air dry below the coldest tubing it reaches, which is Class 2 or Class 3 on a desiccant dryer; a laboratory or food-contact service pushes the oil class to Class 1 or Class 0 and pays for it in an oil-free compressor, a carbon filter, or both. Specifying a tighter class than a service needs buys pressure drop, purge air, and filter elements for nothing. {note}
+
+## Where oil Class 0 is indicated, the compressor shall be oil-free, and the oil content limit that defines Class 0 for the project shall be stated in the purity statement.
+
+## Where a service indicated in the datasheet requires a tighter class than the treatment train delivers, the additional treatment shall be furnished at the point of use or on a separate header under this standard, and the class delivered at that outlet shall be stated in the purity statement.
+
+## Control air delivered to a branch serving pneumatic control devices shall meet the particle, oil, and pressure dew point requirements of ANSI/ISA-7.0.01.
+
+## ANSI/ISA-7.0.01 sets instrument air by a pressure dew point not less than 18°F (10°C) below the lowest temperature the air is exposed to, a particle limit, and an oil limit. It is the standard [[sync/hvac-controls-instrumentation]] expects at the branch it begins at, so meeting it at the source is what lets that standard start at the branch. {note}
+
+# Compressors {toc}
+
+## Compressor Type {toc}
+
+### The compressor type shall be as indicated in the datasheet.
+
```datasheet
−label: Compressor arrangement
+label: Compressor Type
type: select
options:
− - Single compressor
− - Duplex (lead-lag), shared receiver and dryer
− - Multiple compressors with sequencing controls
−default: Single compressor
+ - "Rotary screw"
+ - "Reciprocating"
+ - "Scroll"
+ - "Rotary vane"
+ - "Centrifugal"
+default: "Rotary screw"
```
−## Where continuous facility operation depends on compressed air, a duplex (lead-lag) arrangement shall be provided so that either unit alone can carry the facility base load.
+### A rotary screw runs continuously, is quiet in its enclosure, and is the type sold as a packaged facility compressor across the widest range of capacities, which is why it carries the default; it is least efficient when it runs unloaded, so it suits a load that keeps it loaded or a control that stops it. A reciprocating compressor costs least at small capacity and tolerates an intermittent duty cycle that would wear a screw, and runs hotter and louder and needs a receiver sized to keep its duty cycle down. A scroll is oil-free by construction, nearly silent, and small, and is built in modules that are ganged for capacity. A rotary vane is compact and direct-driven at low speed. A centrifugal is oil-free in the air path and efficient at large steady loads, and surges below its turndown. {note}
−## Lead-lag control alternates the duty unit to equalize wear and brings the lag unit on for peak demand or as standby. A single compressor leaves the facility without air during any failure or routine service of that one machine. {note}
+### The compressor lubrication shall be as indicated in the datasheet.
−## The compressor staging shall be selected for the required discharge pressure.
+```datasheet
+label: Compressor Lubrication
+type: radio
+options:
+ - "Oil-injected (lubricated)"
+ - "Oil-free"
+```
+### An oil-injected compressor seals and cools its compression element with oil and separates most of it from the air before discharge; what remains is removed downstream by coalescing and carbon filtration to the oil class those filters deliver when their elements are within their service life. An oil-free compressor puts no oil into the air path, so the oil class at its discharge does not depend on a filter element, at a higher first cost and, for a rotary screw, a higher specific power. The choice turns on how much of the oil class the owner is willing to hold with filter maintenance. {note}
+
+### The number of compression stages shall be as indicated in the datasheet.
+
```datasheet
−label: Compressor staging
+label: Compression Stages
type: radio
options:
− - Single-stage
− - Two-stage
−default: Single-stage
+ - "Single-stage"
+ - "Two-stage"
+default: manufacturer
```
−## Two-stage compression shall be provided where discharge pressure exceeds approximately 125 psig or where the efficiency at sustained high pressure justifies it.
+### A single-stage machine is the manufacturer's standard for a rotary screw at facility pressures. A second stage with intercooling lowers the specific power at the same pressure and is the construction by which a reciprocating or an oil-free screw reaches the upper end of the facility pressure range, at a higher first cost. {note}
−## Single-stage machines are efficient and adequate for general 100 to 125 psig service. Two-stage compression with intercooling is more efficient and reaches higher pressures, which suits high-pressure headers and continuous high-load duty. {note}
+### The compressor package cooling shall be as indicated in the datasheet.
−## The compressor control mode shall match the facility load profile.
+```datasheet
+label: Compressor Package Cooling
+type: radio
+options:
+ - "Air-cooled"
+ - "Water-cooled"
+default: "Air-cooled"
+```
+### An air-cooled package rejects its heat to the room and needs only the heat rejection path indicated under Service Conditions. A water-cooled package rejects it to a cooling water circuit, holds its discharge temperature independent of the room, and needs that circuit, its treatment, and its freeze protection. {note}
+
+### Where the package is water-cooled, the cooling water supply, return, and drain connections shall be as indicated on [[drawing: the plumbing piping plans]].
+
+### The compressor drive shall be as indicated in the datasheet.
+
```datasheet
−label: Compressor control mode
+label: Compressor Drive
+type: radio
+options:
+ - "Direct-coupled"
+ - "Gear"
+ - "Belt"
+default: manufacturer
+```
+
+### A direct coupling has no ratio and no wearing part between motor and airend; a gear drive sets the airend speed independent of the motor speed and adds a gearbox with its own oil; a belt drive does the same at lower cost and with a belt that stretches, is retensioned, and is replaced. {note}
+
+## Capacity Control {toc}
+
+### The compressor capacity control shall be as indicated in the datasheet.
+
+```datasheet
+label: Compressor Capacity Control
type: select
options:
− - Start-stop
− - Load-unload
− - Modulation
− - Variable-speed drive (VSD)
−default: Load-unload
+ - "Start-stop"
+ - "Load-unload with automatic shutdown"
+ - "Inlet modulation"
+ - "Variable displacement"
+ - "Variable-speed drive"
```
−## Variable-speed drive control should be provided where facility demand varies widely through the day, to reduce energy consumed at part load.
+### Start-stop runs the compressor at full load or not at all and suits a small machine with a receiver large enough to keep its starts per hour within the motor's limit. Load-unload runs the motor continuously and closes the inlet when the receiver reaches the upper pressure, so the unloaded compressor still draws a fraction of full power, and an automatic shutdown stops it after a set unloaded time. Inlet modulation throttles the inlet to follow demand and keeps the motor near full power across most of its range. Variable displacement shortens the effective rotor length on a screw and holds specific power down to about half load. A variable-speed drive follows demand by speed and draws power in proportion to it across a wide range, at a higher first cost and with a drive that needs a clean, cool place to live. The energy difference between them is largest on a load that spends most of its hours well below installed capacity. {note}
−## A VSD compressor matches motor speed to demand and avoids the unloaded-running and blow-down losses of fixed-speed control. The energy saving is largest where average demand is well below installed capacity; at near-constant full load a fixed-speed load-unload machine is competitive and simpler. {note}
+### Where the capacity control is a variable-speed drive, the drive shall be furnished as part of the compressor package, matched to the motor by the compressor manufacturer, and shall not be furnished separately.
−## Rated capacity and discharge pressure shall be as scheduled.
+### Where the capacity control is load-unload, the pressure band between load and unload and the unloaded shutdown time shall be set at startup in accordance with the compressor manufacturer's instructions and recorded in the startup report.
+## Capacity, Pressure, and Redundancy {toc}
+
+### The number of compressors installed shall be as indicated in the datasheet.
+
```datasheet
−label: Compressor rated capacity (per unit)
+label: Number of Compressors
type: range
−unit: SCFM
−min: 10
−max: 1000
−step: 5
−drawing_ref: true
+unit: units
+drawing_ref: "the compressed air equipment schedule on the plumbing drawings"
+min: 1
+max: 6
+step: 1
+default: deferred
```
+### The rated capacity of each compressor at the full-load discharge pressure shall be as indicated in the datasheet.
+
```datasheet
−label: Compressor rated discharge pressure
+label: Rated Capacity of Each Compressor
type: range
+unit: acfm
+drawing_ref: "the compressed air equipment schedule on the plumbing drawings"
+min: 5
+max: 3000
+step: 1
+default: deferred
+```
+
+### The redundancy basis on which the installed capacity is arranged shall be as indicated in the datasheet.
+
+```datasheet
+label: Compressor Redundancy Basis
+type: radio
+options:
+ - "No standby: the installed compressors together carry the design load"
+ - "N+1: the design load is carried with the largest compressor out of service"
+ - "Full standby: each compressor alone carries the design load"
+```
+
+### No standby costs the least and leaves the facility without air during any service of a single machine, which is the right answer where air is a convenience and the wrong one where a line stops without it. N+1 keeps the design load through the loss of one machine with the smallest added capacity, and spreads the hours across machines that alternate as lead. Full standby is N+1 for a two-compressor plant and is the arrangement a sprinkler supervisory supply, a control air supply, or a continuous process asks for. {note}
+
+### The header operating pressure at the outlet of the treatment train shall be as indicated in the datasheet.
+
+```datasheet
+label: Header Operating Pressure
+type: range
unit: psig
−min: 90
+drawing_ref: "the compressed air equipment schedule on the plumbing drawings"
+min: 30
max: 200
−step: 5
−setpoints: [90, 100, 110, 125, 150, 175, 200]
+setpoints: [30, 40, 50, 60, 70, 80, 90, 100, 110, 125, 150, 175, 200]
+default: deferred
```
−## The compressor drive motor shall be sized and wired in accordance with NEC Article 430.
+### The full-load discharge pressure for which each compressor is rated shall be as indicated in the datasheet.
```datasheet
−label: Compressor motor voltage
+label: Compressor Full-Load Discharge Pressure
+type: range
+unit: psig
+derived: "the header operating pressure indicated in the datasheet, plus the pressure drop through the aftercooler, dryer, and filters at rated flow, plus the compressor control band"
+min: 50
+max: 250
+step: 1
+default: derived
+```
+
+### Every psi of header pressure above what the most demanding outlet needs costs compressor power for the whole plant, and every psi of pressure drop through the treatment train is a psi the compressor has to make and the header never sees. The discharge pressure is set from the header pressure upward through those losses, not chosen from the catalog. {note}
+
+### Where the services indicated in the datasheet need pressures that differ by more than the regulator at an outlet can drop efficiently, the higher pressure shall be carried on a separate header or supplied by a booster at the point of use, as indicated on [[drawing: the compressed air piping plans and riser diagram]].
+
+## Motor, Starter, and Controller {toc}
+
+### Each compressor motor shall comply with [[sync/electric-motors]], and shall be rated for continuous duty at the compressor's full-load power without operation in its service factor.
+
+### The motor voltage shall be as indicated in the datasheet.
+
+```datasheet
+label: Compressor Motor Voltage
type: select
+drawing_ref: "the electrical drawings"
options:
− - 208 V, 3Φ
− - 230 V, 3Φ
− - 460 V, 3Φ
−default: 460 V, 3Φ
+ - "115 V, 1Φ"
+ - "230 V, 1Φ"
+ - "208 V, 3Φ"
+ - "230 V, 3Φ"
+ - "460 V, 3Φ"
+ - "575 V, 3Φ"
+default: deferred
```
−## Branch circuit conductors for a continuous-duty motor are sized at not less than 125% of full-load current, and direct-on-line starting draws six to eight times full-load current, which governs disconnect and overcurrent selection. The motor full-load and locked-rotor amperes must be confirmed with the electrical engineer. {note}
+### The starting method shall be as indicated in the datasheet.
−# Receiver {toc}
+```datasheet
+label: Compressor Starting Method
+type: select
+options:
+ - "Across-the-line"
+ - "Wye-delta"
+ - "Solid-state soft start"
+ - "Variable-speed drive"
+default: manufacturer
+```
−## An air receiver shall be provided to store compressed air, dampen pressure pulsation, and allow condensate to drop out before distribution.
+### Across-the-line starting draws the full locked-rotor current and is the manufacturer's standard for a small motor; wye-delta and a solid-state soft starter reduce the inrush to a fraction of it, which a serving utility or an on-site generator can require above a motor size the utility sets; a variable-speed drive starts at the drive's current limit and is the starting method whenever it is also the capacity control. {note}
−## The receiver decouples short-duration demand peaks (tool starts, actuator strokes) from compressor output, so the compressor cycles on average demand rather than chasing every transient. It also provides residence time for water and oil to separate from the air and settle to the drain. {note}
+### Where the serving utility or the on-site standby power source limits motor starting current, the starting method shall reduce the inrush to the limit, and the Contractor shall confirm the limit with the utility before the compressor is ordered.
−## Receiver capacity shall be sized for the facility demand profile and compressor output.
+### The starter shall be furnished as part of the compressor package, and where the compressor manufacturer does not furnish it, the starter shall be as required by [[sync/combination-motor-starters]].
+### Each compressor shall be furnished with a microprocessor controller that displays discharge pressure, discharge temperature, run hours, loaded hours, service intervals, and each active alarm, and that shuts the compressor down on high discharge temperature, high discharge pressure, and motor overload.
+
+### The interface between the compressor controllers and the building automation system shall be as indicated in the datasheet.
+
```datasheet
−label: Receiver tank capacity
+label: Building Automation System Interface
+type: select
+options:
+ - "None"
+ - "Dry contacts for run status and common alarm"
+ - "BACnet MS/TP"
+ - "BACnet/IP"
+ - "Modbus RTU"
+ - "Modbus TCP"
+```
+
+### Dry contacts report whether the compressor is running and whether it is in alarm, which is what a building operator needs to know and all the wiring a small plant justifies. A network interface reports the controller's pressures, temperatures, hours, and individual alarms as points, and the protocol is whichever the building automation system under [[sync/building-automation-system]] speaks; the compressor's own network speaks the compressor manufacturer's protocol, and the gateway between them is part of this package. {note}
+
+### The sequencing of more than one compressor shall be as indicated in the datasheet.
+
+```datasheet
+label: Compressor Sequencing
+type: select
+derived: "the number of compressors and the redundancy basis indicated in the datasheet"
+options:
+ - "None: single compressor"
+ - "Lead-lag by the compressor controllers over a controller network"
+ - "Dedicated system controller on a common pressure signal"
+default: derived
+```
+
+### Two compressors with networked controllers alternate lead on run hours and bring the lag unit on at a lower pressure band, which is sequencing enough for a duplex plant. A dedicated system controller reads one header pressure, holds a narrower band than compressors on their own switches can, and chooses which machines to run and at what point to trim with the variable-speed unit, which is where a plant of three or more machines or of mixed sizes recovers the energy that cascaded pressure bands waste. {note}
+
+### Where more than one compressor is installed, the sequencing shall alternate the lead compressor so that run hours are equalized, and shall start a lag compressor before the header pressure falls below the minimum pressure stated in the pipe sizing calculation.
+
+### The sound pressure level of each compressor package at full load shall not exceed the value indicated in the datasheet, measured at 1 m in accordance with ISO 2151.
+
+```datasheet
+label: Maximum Compressor Sound Pressure Level at 1 m
type: range
−unit: gal
+unit: dBA
min: 60
−max: 2000
−step: 20
−drawing_ref: true
+max: 95
+setpoints: [60, 65, 70, 75, 80, 85, 90, 95]
```
−## The receiver shall provide a minimum of 10 minutes of storage at average system demand.
+### A packaged rotary screw in its enclosure is sold in the range of the low to high seventies at 1 m, an open reciprocating compressor well above that, and a scroll below it. OSHA 29 CFR 1910.95 sets an action level of 85 dBA as an eight-hour average, so a package that is louder than that in a room someone works in all day puts the room in a hearing conservation program. A lower limit buys a quieter enclosure or a quieter type, and the limit is what settles whether the compressor can share a space with people. {note}
−## A common first-pass rule for variable-demand systems is roughly 1 gallon of receiver volume per SCFM of compressor output; the larger of the two checks governs. This follows the UFC 3-420-02 guideline. {note}
+### The enclosure rating of the compressor package electrical enclosure, the starter, and any system controller shall be as indicated in the datasheet.
−## The receiver shall be a pressure vessel constructed and stamped in accordance with ASME BPVC Section VIII, Division 1, with the MAWP shown on the nameplate.
+```datasheet
+label: Electrical Enclosure Rating
+type: select
+options:
+ - "NEMA Type 1"
+ - "NEMA Type 2"
+ - "NEMA Type 3R"
+ - "NEMA Type 4"
+ - "NEMA Type 4X"
+ - "NEMA Type 12"
+default: "NEMA Type 1"
+```
−## A pressure-relief device shall be installed on the receiver, set so that receiver pressure cannot exceed the MAWP by more than 10% under any condition.
+### A Type 1 enclosure keeps fingers out of a dry, indoor, conditioned room and is the rating the equipment comes with. Type 12 adds a gasket against the dust a shop or a compressor room raises; Type 3R sheds rain and is the least that an outdoor enclosure needs; Type 4 holds against a hose; Type 4X holds against a hose in a corrosive atmosphere. {note}
−## OSHA 29 CFR 1910.169 requires this as a federal mandate. The relief capacity must exceed the compressor's full delivery so the receiver cannot be over-pressured even with the inlet valve fully open. {note}
+### Electrical enclosures of the system installed outdoors shall be rated NEMA Type 3R or higher.
−## A pressure gauge shall be installed on the receiver.
+### Electrical enclosures of the system installed where equipment is washed down shall be rated NEMA Type 4 or higher.
−## The pressure gauge shall be readable from the operating position.
+### Electrical enclosures of the system installed in a corrosive atmosphere shall be rated NEMA Type 4X.
−## A manual drain valve shall be installed at the lowest point of the receiver.
+# Air Treatment {toc}
−## OSHA 29 CFR 1910.169 requires a drain at the lowest point so accumulated condensate can be removed. An automatic drain may supplement the manual drain but does not replace it for inspection and service purposes. {note}
+## Aftercooler and Separator {toc}
−# Air Treatment {toc}
+### An aftercooler shall be provided at the discharge of each compressor, arranged as indicated in the datasheet.
−## An air treatment train shall be provided to deliver the required purity class at each point of use, addressing particulates, moisture, and oil.
+```datasheet
+label: Aftercooler Arrangement
+type: radio
+options:
+ - "Integral to the compressor package"
+ - "Separate air-cooled aftercooler"
+ - "Separate water-cooled aftercooler"
+default: "Integral to the compressor package"
+```
−## ISO 8573-1 classifies air independently for solid particles, water (dew point), and oil. A complete train typically comprises an aftercooler and moisture separator at the compressor discharge, a dryer sized for the required dew point, and point-of-use coalescing and particulate filtration. Each contaminant is addressed by the component suited to it; one device does not cover all three. {note}
+### A packaged compressor includes its aftercooler, and the air leaves the package within a stated approach to the cooling medium, which is why the integral arrangement carries the default. A separate aftercooler is the arrangement for a compressor sold without one, for an existing compressor, and for a plant where the discharge temperature at the dryer has to be held lower than the package approach allows; air-cooled rejects to the room and water-cooled to a cooling circuit. {note}
−## The required air purity class shall be specified at each point of use per ISO 8573-1.
+### The aftercooler shall deliver air to the dryer at a temperature not exceeding the dryer's rated inlet temperature, corrected for the project ambient, when the compressor is at full load in the room at its design temperature.
+### A moisture separator with an automatic drain shall be provided downstream of each aftercooler, upstream of the receiver or dryer.
+
+### Cooling the discharge air condenses most of the water the compressor took in, and the separator takes that water out as liquid before it reaches the dryer; a dryer that receives it as liquid is being asked to do with refrigeration or desiccant what the aftercooler does with a fan. {note}
+
+## Dryer {toc}
+
+### The dryer type shall be as indicated in the datasheet.
+
```datasheet
−label: Required ISO 8573-1 purity class (particles.water.oil)
+label: Dryer Type
type: select
options:
− - 3.4.3 (general shop / maintenance)
− - 2.2.2 (general laboratory)
− - 2.2.1 (instrument air)
− - 1.2.1 (food-contact / critical)
−default: 3.4.3 (general shop / maintenance)
+ - "Refrigerated, non-cycling"
+ - "Refrigerated, cycling"
+ - "Heatless regenerative desiccant"
+ - "Heated purge regenerative desiccant"
+ - "Blower purge regenerative desiccant"
+ - "Membrane"
+ - "No dryer"
```
−## Typical class assignments by application: general shop and maintenance air at Class 3.4.3 (particles.water.oil); instrument air at Class 2.2.1; general laboratory air at Class 2.2.2; food-contact air at Class 1.2.1 or better. The class drives the dryer dew point and the filtration grades and must be set before the train is selected. {note}
+### A refrigerated dryer cools the air to a few degrees above freezing and drains the condensate, so its pressure dew point is a water Class 4 to Class 6 and no lower; a non-cycling unit runs its refrigeration circuit continuously and a cycling unit stores cold in a thermal mass or varies its compressor speed and draws power in proportion to the load. A regenerative desiccant dryer adsorbs water in one tower while the other regenerates and reaches water Class 2 or Class 1; a heatless unit regenerates with a share of the dried air in the range of a sixth of its rated flow, a heated purge unit with a smaller share heated by an element, and a blower purge unit with ambient air heated and blown through the bed, with little or none of the dried air, so the three are the same dew point bought with purge air, electricity, or first cost. A membrane dryer has no moving parts and no electricity, bleeds a share of the air continuously, and suits a small flow at a point of use. No dryer is the arrangement where the water class the service needs is met by the aftercooler and separator alone. {note}
−## An aftercooler shall be provided downstream of the compressor to reduce discharge air temperature and condense the bulk of the moisture before it enters the dryer.
+### The dryer shall deliver the pressure dew point corresponding to the water class indicated in the datasheet at the full capacity of the compressors that can run at the same time, at the inlet temperature and pressure the aftercooler delivers, and at the compressor room design temperature.
+### The dryer redundancy shall be as indicated in the datasheet.
+
```datasheet
−label: Aftercooler type
+label: Dryer Redundancy
type: radio
+derived: "the compressor redundancy basis indicated in the datasheet"
options:
− - Air-cooled
− - Water-cooled
−default: Air-cooled
+ - "Single dryer rated for the plant capacity"
+ - "Duplex dryers, each rated for the plant capacity"
+ - "One dryer per compressor, each rated for its compressor"
+default: derived
```
−## Removing the heat of compression here drops out most of the water as liquid, which the moisture separator captures, so the dryer receives a far smaller moisture load. {note}
+### A single dryer sized for the plant is the least equipment and makes the dryer the one component whose service stops the air; duplex dryers keep the dew point through the service of either; a dryer per compressor follows the compressor redundancy and is the arrangement of a modular plant where each compressor is packaged with its own treatment. A plant with no compressor standby rarely justifies dryer standby, and a plant with full compressor standby has little reason to give it up at the dryer. {note}
−## A moisture separator with automatic drain shall be installed downstream of the aftercooler to remove condensed liquid before the dryer.
+### Whether the dryer is furnished with a valved bypass shall be as indicated in the datasheet.
−## A dryer shall be provided to deliver the pressure dew point required by the application and the distribution environment.
+```datasheet
+label: Dryer Bypass
+type: radio
+options:
+ - "Three-valve bypass around the dryer"
+ - "No bypass"
+```
+### A bypass keeps air flowing while the dryer is serviced, and it is also the path by which wet air reaches the distribution when a valve is left open or opened to get pressure back, which fills the piping with the water the dryer existed to keep out. Duplex dryers remove the reason for a bypass; a single dryer on a service that can tolerate wet air for the length of a repair keeps one. {note}
+
+### Where a bypass is provided, the bypass valve shall be locked closed and tagged, and the as-built drawings shall record its location.
+
+### A refrigerated dryer shall be listed and labeled by a nationally recognized testing laboratory, and its refrigeration circuit shall be factory-charged and sealed.
+
+### A regenerative desiccant dryer shall be furnished with a purge control that reduces purge air in proportion to the moisture load, and with a dew point indicator or transmitter at its outlet.
+
+### A heatless dryer purges on a fixed cycle sized for its rated moisture load, so at half load it is still spending the same purge air; a control that senses the outlet dew point or the bed temperature and extends the cycle recovers most of that air. {note}
+
+## Filtration {toc}
+
+### The filters in the treatment train shall be as indicated in the datasheet.
+
```datasheet
−label: Dryer type
−type: select
+label: Treatment Train Filters
+type: checkbox
options:
− - Refrigerated
− - Desiccant (regenerative)
− - Combination (refrigerated + desiccant polish)
−default: Refrigerated
+ - "Particulate pre-filter upstream of the dryer"
+ - "Coalescing filter upstream of the dryer"
+ - "High-efficiency coalescing filter downstream of the dryer"
+ - "Activated carbon filter for oil vapor"
+ - "Particulate after-filter downstream of a desiccant dryer"
+ - "Point-of-use filters at the outlets"
+default:
+ - "Coalescing filter upstream of the dryer"
```
+### Each filter removes one kind of contaminant and does nothing for the others. A coalescing filter collects oil aerosol and the water the separator missed and drains them; a high-efficiency coalescing element delivers the oil Class 1 aerosol limit and the particle Class 2 count at the cost of a higher pressure drop; an activated carbon element adsorbs oil vapor, which no coalescing filter touches, and is the only way to Class 1 total oil from a lubricated compressor; a particulate after-filter catches the desiccant dust a regenerative dryer sheds. Every element in the train adds pressure drop the compressor pays for, and an element past its life adds more, so the train is as short as the class allows. {note}
+
+### Where a regenerative desiccant dryer is installed, a particulate after-filter shall be installed at its outlet.
+
+### Where the water class indicated in the datasheet is Class 3 or tighter, a coalescing filter shall be installed upstream of the dryer so that liquid water and oil do not reach the desiccant.
+
+### Each filter shall be rated by its manufacturer in accordance with ISO 12500 for the contaminant it removes, and each shall be furnished with a differential pressure indicator and, where the element collects liquid, an automatic drain.
+
+### Filters shall be sized for the full capacity of the compressors that can run at the same time, at a pressure drop at rated flow not exceeding the value stated in the pipe sizing calculation.
+
+# Receivers {toc}
+
+## Receiver Arrangement {toc}
+
+### The receiver arrangement shall be as indicated in the datasheet.
+
```datasheet
−label: Required outlet pressure dew point
−type: select
+label: Receiver Arrangement
+type: radio
options:
− - 35°F to 39°F (refrigerated, indoor heated distribution)
− - −40°F (desiccant, instrument / freeze-exposed)
− - −100°F (desiccant, extreme dry)
−default: 35°F to 39°F (refrigerated, indoor heated distribution)
+ - "Wet receiver upstream of the dryer"
+ - "Dry receiver downstream of the dryer"
+ - "Wet receiver upstream and dry receiver downstream of the dryer"
```
−## A refrigerated dryer shall deliver a pressure dew point of 35°F to 39°F (2°C to 4°C) at operating pressure.
+### A wet receiver sits between the aftercooler and the dryer, takes the pulsation and the surge from the compressor, gives condensate time to fall out before the dryer, and steadies the flow the dryer sees. A dry receiver sits after the treatment train, holds dried air against a demand peak without pulling the compressor on, and is the volume a pressure/flow controller regulates from. One receiver of either kind is the usual plant; both together separate the compressor's control band from the header's and are the arrangement where the plant is controlled by a system controller or a pressure/flow controller. {note}
−## This dew point is adequate for general-service air distributed entirely within heated indoor space and is the usual choice for shop and maintenance systems. It is not adequate where any piping is exposed to freezing temperatures. {note}
+### The volume of each receiver shall be as indicated in the datasheet.
−## A desiccant dryer shall be provided where the application requires a pressure dew point of −40°F (−40°C) or lower, such as instrument air or any freeze-exposed distribution.
+```datasheet
+label: Receiver Volume
+type: range
+unit: gal
+drawing_ref: "the compressed air equipment schedule on the plumbing drawings"
+min: 20
+max: 5000
+step: 10
+default: deferred
+```
−## Refrigerant-circuit refrigerated dryers shall comply with ASHRAE 15.
+### The receiver volume shall be not less than the compressor manufacturer's published minimum for the capacity control and the starts per hour of the compressor it serves.
−## Desiccant dryers reach −40°F pressure dew point routinely and −100°F for extreme cases. {note}
+### The receiver orientation shall be as indicated in the datasheet.
−## Point-of-use coalescing and particulate filtration shall be provided to achieve the specified oil and particle classes at the use point.
+```datasheet
+label: Receiver Orientation
+type: radio
+options:
+ - "Vertical"
+ - "Horizontal"
+ - "Horizontal, tank-mounted beneath the compressor package"
+default: manufacturer
+```
+### A vertical receiver takes the least floor space and drains from a small bottom head; a horizontal receiver fits under a low ceiling and drains along its length; a tank-mounted package puts a small compressor on top of its receiver as one shipped piece, which is the manufacturer's standard offering at the sizes it is made in. {note}
+
+### The receiver interior protection shall be as indicated in the datasheet.
+
```datasheet
−label: Point-of-use filtration grade
+label: Receiver Interior Protection
+type: radio
+options:
+ - "Uncoated steel"
+ - "Hot-dip galvanized"
+ - "Internally coated"
+```
+
+### A wet receiver holds condensate and warm, oxygen-rich air against bare steel, and rusts from the water line down; the rust goes downstream as particles and the wall goes thin at the bottom head. Galvanizing and an internal coating both put a barrier between the water and the steel, at a cost that a dry receiver on dry air has little reason to pay and a wet receiver on an uncoated compressor discharge has every reason to. {note}
+
+## Receiver Construction and Appurtenances {toc}
+
+### Each receiver shall be constructed, inspected, stamped, and registered in accordance with ASME BPVC Section VIII, Division 1, with the MAWP and the design temperature on the nameplate.
+
+### The MAWP of each receiver shall be not less than the setting of the relief valve that protects it, and that setting shall be not less than the maximum discharge pressure the compressors can produce.
+
+### Each receiver shall be fitted with a relief valve, set not higher than the MAWP, whose relieving capacity is not less than the total rated capacity of every compressor that can discharge into it, so that the pressure in the receiver cannot exceed the MAWP by more than 10 percent, in accordance with OSHA 29 CFR 1910.169 and ASME BPVC Section VIII.
+
+### Each receiver shall be fitted with a pressure gauge readable from the floor.
+
+### Each receiver shall be fitted with a drain valve at its lowest point, operable by hand, in addition to any automatic drain furnished under Condensate Management.
+
+### OSHA 29 CFR 1910.169 requires the gauge, the relief valve, and the drain at the low point on every air receiver, so these are federal requirements and not a design choice. The hand drain stays because it is the one that works when the automatic drain has failed, and because it is how the automatic drain is proven. {note}
+
+### Each receiver shall be provided with an inspection opening as required by ASME BPVC Section VIII for its size, and shall be set so that the opening and the drain are accessible.
+
+### Each receiver shall be provided with an isolation valve at its outlet and, where more than one compressor discharges into it, a check valve at each compressor connection.
+
+# Condensate Management {toc}
+
+## Condensate shall be drained automatically from each separator, receiver, dryer, filter that collects liquid, and drip leg, by a drain of the type indicated in the datasheet.
+
+```datasheet
+label: Automatic Condensate Drain Type
type: select
options:
− - General-purpose particulate (5 µm)
− - Coalescing (1 µm, oil aerosol)
− - High-efficiency coalescing (0.01 µm)
− - Coalescing + activated carbon (oil vapor)
−default: Coalescing (1 µm, oil aerosol)
+ - "Mechanical float drain"
+ - "Timed solenoid drain"
+ - "Zero-air-loss level-sensing drain"
```
−## Coalescing filters remove oil aerosol and fine particulate; a particulate after-filter protects against desiccant fines where a desiccant dryer is used. Filtration grade is selected to meet the ISO class, not over-specified, because each filter stage adds pressure drop. {note}
+## A float drain opens on a float and needs no power, and its small orifice is the one that an oily condensate sticks shut; a timed solenoid opens on a schedule whether there is condensate or not, and every opening that finds none vents compressed air the plant paid to make; a level-sensing drain opens only on a sensed level and closes before air escapes, needs power and a sensor, and recovers its cost in the air the timed drain would have spent. {note}
+## Condensate from an oil-injected compressor shall not be discharged to a drain until its oil concentration is below the limit of the authority that receives the discharge, confirmed in the informational submittal.
+
+## The oil-water separation provided shall be as indicated in the datasheet.
+
+```datasheet
+label: Condensate Oil-Water Separation
+type: select
+derived: "the compressor lubrication indicated in the datasheet and the oil concentration limit of the authority that receives the discharge"
+options:
+ - "None: condensate to drain"
+ - "Gravity and adsorption oil-water separator"
+ - "Collection tank for off-site disposal"
+default: derived
+```
+
+## The condensate of an oil-injected compressor is water carrying the oil the air separator and the coalescing filters removed, and a sewer authority limits oil in its influent to a concentration that raw compressor condensate exceeds. A gravity and adsorption separator settles and then adsorbs the oil to the concentration it is rated for and discharges the water; a collection tank holds everything for a hauler and suits a site whose authority accepts no oily discharge or whose condensate is small. An oil-free plant produces condensate that carries only what the intake air carried. {note}
+
+## Condensate drain discharge and separator discharge shall be piped to an indirect waste receptor through an air gap, at the location indicated on [[drawing: the plumbing drainage plans]].
+
+## Drain discharge piping shall be sized and routed so that a drain discharging under full system pressure does not spray, and shall not be manifolded with the discharge of another drain unless the drains are of the level-sensing type and the manifold is sized for them.
+
+## A timed or float drain discharging into a common line pressurizes it each time it opens, and the back pressure holds the other drains on the line shut until the slug passes. {note}
+
# Distribution Piping {toc}
−## Distribution piping shall comply with ASME B31.1 for systems at or below 150 psig in non-process buildings, and with ASME B31.3 where system pressure exceeds 150 psig or where piping is in a process-classified area.
+## Governing Piping Code {toc}
−## The piping material shall be selected for the service pressure, air quality, and corrosion environment.
+### Distribution piping shall be designed, fabricated, installed, examined, and tested in accordance with the piping code indicated in the datasheet.
```datasheet
−label: Distribution piping material
+label: Governing Piping Code
type: select
+derived: "the header operating pressure and the pipe sizes indicated, and whether the piping serves a process unit, applied to the scope statements of ASME B31.9, ASME B31.1, and ASME B31.3"
options:
− - Carbon steel, Schedule 40 (ASTM A53 black)
− - Carbon steel, Schedule 80 (ASTM A53 black)
− - Copper, Type L (ASTM B88)
− - Aluminum, modular push-fit
− - Stainless steel
−default: Carbon steel, Schedule 40 (ASTM A53 black)
+ - "ASME B31.9"
+ - "ASME B31.1"
+ - "ASME B31.3"
+default: derived
```
−## Internally galvanized steel pipe shall not be used for compressed air distribution.
+### ASME B31.9 covers building services piping, including compressed air within the pressure and size limits its scope states, and is the code written for the piping this standard describes; ASME B31.1 covers power plant and industrial piping and is the code many existing facility specifications cite; ASME B31.3 covers process piping and is the code a process unit's piping is designed to regardless of pressure. The three differ in the examination and the test pressure they require, so the code is settled before the test plan is written. {note}
−## At compressed air velocities the internal zinc coating flakes off and the particles travel downstream to clog filters, regulators, and tool valves. Black steel (Schedule 40 or 80 per ASTM A53), Type L copper, or modular aluminum are the appropriate choices. {note}
+## Piping Material {toc}
−## Modular aluminum push-fit piping should be considered where leak reduction and reconfigurability are priorities.
+### The distribution piping material shall be as indicated in the datasheet.
−## Aluminum modular systems install quickly, have a smooth bore that minimizes pressure drop, and their sealed joints leak far less than threaded steel, which directly reduces the compressor energy wasted feeding a leaky distribution network. {note}
+```datasheet
+label: Distribution Piping Material
+type: select
+options:
+ - "Black steel, ASTM A53 Schedule 40"
+ - "Galvanized steel, ASTM A53 Schedule 40"
+ - "Stainless steel, ASTM A312 Type 304L"
+ - "Stainless steel, ASTM A312 Type 316L"
+ - "Copper tube, ASTM B88 Type L"
+ - "Aluminum modular piping rated for compressed air"
+ - "High-density polyethylene rated for compressed air"
+```
−## Distribution piping shall be sized so that total pressure drop from the receiver to the worst-case outlet does not exceed the specified limit at full design flow.
+### Black steel is the lowest material cost, is threaded or welded by any pipefitter, and rusts on the inside wherever condensate stands, sending scale downstream to the filters and outlets. Galvanized steel resists that rust with zinc until the zinc is consumed or flakes, and the flakes travel to the same places. Stainless steel neither rusts nor flakes and costs the most to buy and to join, and is the pipe for an oil-free plant whose air class the pipe itself has to protect. Copper tube is clean inside, is brazed or soldered by a plumber, and is limited by its joint temperature at the discharge end. Aluminum modular piping is clean inside, is assembled with push-fit or compression fittings in a fraction of the labor, is reconfigured without hot work, and is rated by its manufacturer to a temperature that keeps it away from the compressor discharge. Polyethylene rated for compressed air is light, corrosion-free, and fused or mechanically joined, and carries the same temperature limit. {note}
+### Thermoplastic pipe that its manufacturer does not rate for compressed air service shall not be used anywhere in the system.
+
+### A thermoplastic pipe fails in compressed gas service by fracture, not by leak, and the stored energy of the gas drives the fragments outward; the manufacturers of plumbing-grade PVC and CPVC state in their own literature that their pipe is not for compressed gases, and OSHA has published a hazard bulletin on that use. {note}
+
+### Piping between the compressor discharge and the aftercooler inlet shall be steel or stainless steel rated for the compressor discharge temperature, and soldered, push-fit, compression, and thermoplastic joints shall not be used in that section.
+
+### Pipe, fittings, valves, and joints throughout the system shall be rated for not less than the relief valve setting of the receiver at the maximum temperature of the air at the point of installation.
+
+### Fittings for steel pipe shall be malleable iron threaded fittings in accordance with ASME B16.3, forged steel fittings in accordance with ASME B16.11, or wrought steel buttwelding fittings in accordance with ASME B16.9, matched to the joining method.
+
+### Fittings for copper tube shall be wrought copper pressure fittings in accordance with ASME B16.22.
+
+### Fittings, valves, and outlets for a modular aluminum or polyethylene system shall be the components of that system furnished by its manufacturer, and a transition to another material shall be made with the transition fitting that manufacturer furnishes.
+
+## Joining {toc}
+
+### The joining method for the distribution piping shall be as indicated in the datasheet.
+
```datasheet
−label: Maximum total distribution pressure drop
+label: Piping Joining Method
type: select
options:
− - 2 psig (general service)
− - 1 psig (instrument air header)
−default: 2 psig (general service)
+ - "Threaded"
+ - "Welded"
+ - "Grooved mechanical couplings"
+ - "Brazed"
+ - "Soldered"
+ - "Press-connect"
+ - "Push-fit or compression fittings of a modular system"
```
−## Pressure at the worst-case outlet shall be verified to remain at or above 90 psig under full design load.
+### A threaded joint is made with hand tools and is the joint that leaks, a little at every thread, for the life of the system; a welded joint leaks nowhere and costs a welder, a procedure, and a hot work permit; a grooved coupling joins steel without either and depends on a gasket. A brazed joint on copper holds at the discharge temperature and a soldered joint does not; a press-connect joint is made with a tool in seconds and depends on its seal element; the push-fit and compression fittings of a modular system are the system's own joints, made and remade without tools, and are what the system's leak rating is based on. Leakage is the operating cost of a joining method, and a plant that runs a compressor to feed its threads has bought the cheapest joint at the highest price. {note}
−## Sizing on average flow alone undersizes the header so that end-of-line tools starve at peak demand. The sizing calculation must check the farthest, highest-demand outlet under simultaneous full load, not just the steady-state condition. {note}
+### Threaded joints shall be made with a sealant compatible with the compressor lubricant and with the air class, applied to the male threads only.
−## A high-pressure header with pressure-reducing stations shall be provided where specialty equipment requires pressure above the general-service level.
+### Brazed joints shall be made with a filler metal in accordance with AWS A5.8/A5.8M, and copper joints between the compressor discharge and the aftercooler and at the dryer inlet shall be brazed, not soldered.
+### Gaskets, seal elements, and O-rings throughout the system shall be of a material compatible with the compressor lubricant where the compressor is oil-injected, and with the air class where the compressor is oil-free.
+
+### An ethylene propylene seal swells in mineral oil and a nitrile seal does not, so a grooved or press system whose standard gasket is EPDM is on the wrong gasket for a lubricated plant unless the oil-resistant gasket is ordered. {note}
+
+## Sizing and Configuration {toc}
+
+### Distribution mains and branches shall be sized for the simultaneous design flow indicated on [[drawing: the compressed air demand and outlet schedule]].
+
+### The pressure drop from the outlet of the treatment train to the hydraulically farthest outlet at the design flow shall not exceed the value indicated in the datasheet.
+
```datasheet
−label: System pressure architecture
+label: Maximum Distribution Pressure Drop
+type: range
+unit: psi
+min: 1
+max: 10
+setpoints: [1, 2, 3, 4, 5, 7.5, 10]
+```
+
+### Every psi of distribution pressure drop is a psi of compressor discharge pressure, and compressor power rises with discharge pressure, so a tighter drop limit buys lower energy for the life of the plant with larger pipe bought once. A limit in the low single digits is the range at which the pipe cost and the energy cost of a facility system usually cross; a looser limit suits a short run or an intermittent load, and a tighter one suits an instrument header whose regulators need a stable upstream pressure. {note}
+
+### The air velocity in mains at the design flow shall not exceed the value indicated in the datasheet.
+
+```datasheet
+label: Maximum Air Velocity in Mains
+type: range
+unit: ft/s
+min: 10
+max: 40
+setpoints: [10, 15, 20, 25, 30, 40]
+```
+
+### Velocity is what carries condensate and scale down the pipe and past the drip legs instead of letting it fall out, and what makes a main audible. A low velocity limit keeps the water in the drip legs and the noise out of the shop and costs pipe size; a high limit is tolerable in a short dry run after a desiccant dryer. {note}
+
+### The spare capacity for which the mains are sized above the design flow shall be as indicated in the datasheet.
+
+```datasheet
+label: Main Sizing Reserve Above Design Flow
+type: range
+unit: '%'
+min: 0
+max: 100
+setpoints: [0, 10, 25, 50, 100]
+```
+
+### A main sized to the design flow and no more is the cheapest main on the day it is installed and the first thing replaced when an outlet is added. Reserve in the main is cheap compared with reserve in the compressor, because the pipe is sized once and the compressor is replaced when it is outgrown, and the reserve a facility carries is a judgment about how it will grow. {note}
+
+### The main configuration shall be as indicated in the datasheet.
+
+```datasheet
+label: Main Configuration
type: radio
options:
− - Single-pressure header (general service)
− - General-service header plus dedicated high-pressure header
−default: Single-pressure header (general service)
+ - "Dead-end main with branches"
+ - "Loop main"
```
−## Where part of the facility needs 150 to 200 psig and the rest needs 100 psig, a dedicated high-pressure header fed by a booster, with regulators dropping to general service at the use points, is more efficient than running the whole facility at the higher pressure. {note}
+### A loop feeds every branch from two directions, halves the effective length the farthest outlet sees, and keeps air at every outlet when one section is valved off for work; it costs the closing run of pipe. A dead-end main is the shorter run and suits a building whose outlets lie along one path from the compressor. {note}
−## Distribution mains should be looped and sized with reserve capacity for future expansion.
+### Where the services indicated in the datasheet include instrument or control air, the arrangement by which it is distributed shall be as indicated in the datasheet.
−## A looped main feeds each branch from two directions, halving the effective length and pressure drop, and reserve capacity built in at construction is far cheaper than retrofitting a larger header later. Calling out a design reserve at the outset is a low-cost hedge against facility growth. {note}
+```datasheet
+label: Instrument and Control Air Distribution
+type: radio
+options:
+ - "Shared header with the general service, treated at the point of use"
+ - "Separate header from the shared treatment train"
+ - "Separate treatment train and header"
+```
−## Instrument-quality air shall be distributed in a header separate from general shop air where instrument accuracy or actuator reliability depends on air quality.
+### Point-of-use treatment on a shared header puts a small dryer and filter at each instrument branch and leaves the whole header at shop air class, which suits a few scattered instrument loads. A separate header from the shared train gives the instruments a pipe that shop air surges, scale, and blow-off demand never enter, which is the usual arrangement where a plant serves both. A separate train and header isolates the instrument air from every shop air failure including the dryer's and is the arrangement where the control air keeps a process or a building running. {note}
−## Shop air carries more particulate, moisture, and oil than instrument loops tolerate. Tapping instruments off a shop header contaminates regulators and positioners and degrades control accuracy, so the two services are kept on separate, independently treated headers. {note}
+## Isolation Valves {toc}
−## Each branch takeoff and terminal outlet shall be located as shown.
+### Isolation valves shall be of the type indicated in the datasheet.
```datasheet
−label: Terminal outlet type
+label: Isolation Valve Type
type: select
options:
− - Quick-connect coupler
− - Filter-regulator-lubricator (FRL) drop
− - Filter-regulator (no lubricator) drop
− - Hose reel station
−default: Filter-regulator (no lubricator) drop
+ - "Full-port ball"
+ - "Butterfly"
+ - "Gate"
+default: "Full-port ball"
```
−## Outlet and branch routing, drop locations, and header extents shall be as shown on the drawings.
+### A full-port ball valve opens a quarter turn, shows its position by its handle, seals bubble-tight, and adds no pressure drop, which is why it is the valve on nearly every compressed air line and carries the default. A butterfly valve is lighter and cheaper in the larger main sizes and leaves its disc in the flow. A gate valve seals well and takes many turns to open, which is what keeps it off a line that is valved often. {note}
−## See [[drawing: compressed air distribution plan]]. {note}
+### Isolation valves shall be installed at the discharge of each compressor, at the inlet and outlet of each dryer and filter that can be serviced in place, at the outlet of each receiver, at the base of each riser, at each branch takeoff from a main, at each drop, and at each connection to a system furnished under another standard.
−# Condensate Management {toc}
+### Each valve shall be rated for the system design pressure and the temperature at its location, and shall be of a construction whose seats and seals comply with the compatibility requirement under Joining.
−## Condensate shall be removed automatically from the receiver, dryer, filters, and drip legs, and managed to comply with the discharge requirements.
+## Drops, Outlets, and Couplers {toc}
−## Compressed air condensate accumulates at every cool point in the system. Left in place it carries downstream as slugs of water and, in lubricated systems, oil. The drain method is selected to remove condensate reliably without wasting compressed air. {note}
+### Each branch and drop shall be taken from the top of the main through a fitting that turns the branch up before it turns down.
−## The condensate drain method shall be selected for reliability and air economy.
+### Condensate runs along the bottom of a main, and a branch taken from the side or the bottom receives it; a branch that leaves the top of the pipe receives only air. {note}
+### Each drop shall terminate below its lowest outlet in a drip leg with a drain, and the outlet shall be taken from the side of the drop above the drip leg.
+
+### The outlet assembly at each drop shall be as indicated in the datasheet.
+
```datasheet
−label: Condensate drain type
+label: Outlet Assembly
type: select
options:
− - Manual drain valve
− - Automatic timed solenoid drain
− - Zero-loss demand (electronic level) drain
−default: Zero-loss demand (electronic level) drain
+ - "Isolation valve and quick-connect coupler"
+ - "Filter and regulator with coupler"
+ - "Filter, regulator, and lubricator with coupler"
+ - "Hose reel with filter and regulator"
+ - "Valved outlet with pipe thread for a hard connection"
```
−## Zero-loss demand drains should be specified to avoid the continuous compressed air loss of timed drains.
+### A bare coupler delivers header pressure and header air class and suits an outlet feeding a tool that has its own regulator or a machine that has its own treatment. A filter and regulator drop sets the outlet pressure and takes out the water and scale the drop collected, which is what most tools and all instruments need. A lubricator adds oil mist for tools that need it and poisons anything downstream that does not, so it belongs only on a drop that serves lubricated tools and never on one that serves a paint line, an instrument, or a laboratory. A hose reel adds the hose and its storage to a filter and regulator drop. A hard connection serves a machine with a fixed demand. {note}
−## A timed solenoid drain opens on a schedule whether or not condensate is present, venting compressed air each cycle. A demand drain opens only when a sensed liquid level requires it, eliminating that loss; the energy saving usually repays the higher device cost. {note}
+### The quick-connect coupler profile shall be as indicated in the datasheet.
−## An oil-water separator shall be provided to treat condensate from all lubricated compressors before discharge to the sanitary drain.
+```datasheet
+label: Quick-Connect Coupler Profile
+type: select
+options:
+ - "Industrial interchange, 1/4 in. body"
+ - "Industrial interchange, 3/8 in. body"
+ - "Automotive interchange"
+ - "High-flow interchange"
+default: "Industrial interchange, 1/4 in. body"
+```
−## Oily condensate discharged to a sanitary drain violates environmental regulations. The separator must reduce oil content below the local sewer authority limit, which is commonly below 15 mg/L; the actual limit must be confirmed with the authority having jurisdiction. {note}
+### The industrial interchange in the 1/4 in. body is the profile most tools in North America are plugged with, which is why it carries the default; the 3/8 in. body and the high-flow profile pass more air to a tool that is starved through a 1/4 in. coupler; the automotive interchange is the profile of many light-duty tools and does not mate with the industrial profile. A facility with two profiles on its walls has tools that reach no outlet. {note}
−## Condensate from lubricated compressors shall not be discharged to the sanitary drain without passing through an oil-water separator that meets the local sewer authority oil-content limit.
+### Whether couplers vent the hose before release shall be as indicated in the datasheet.
−# Cross-Connection Prohibition {toc}
+```datasheet
+label: Coupler Safety Venting
+type: radio
+options:
+ - "Standard coupler"
+ - "Vent-before-release safety coupler"
+default: "Standard coupler"
+```
−## The general-service compressed air system shall not be cross-connected to any medical air, oxygen, vacuum, or other piped gas system.
+### A standard coupler releases the plug with the hose still pressurized, and the hose whips. A safety coupler vents the hose on the first motion and releases the plug on the second, at a higher cost per coupler and a second motion the user has to learn. {note}
−## General-service air is not certified to medical purity and is not monitored or alarmed to NFPA 99 Level 1 requirements. Any physical connection between this system and a medical gas, oxygen, or other piped gas system is prohibited; the prohibition must be stated explicitly on any project touching a healthcare facility so it survives field coordination. See [[sync/medical-gas-systems]]. {note}
+### An outlet or nozzle furnished for blow-off or cleaning shall limit the dead-ended pressure at the nozzle to 30 psi and shall be furnished with chip guarding, in accordance with OSHA 29 CFR 1910.242(b).
−## No connection shall be made between the general-service compressed air system and any medical air, oxygen, or other piped gas system.
+### The location of each drop and outlet shall be as indicated on [[drawing: the compressed air piping plans]].
−# Noise and Vibration Control {toc}
+## Supports, Identification, and Protection {toc}
−## The compressor shall be isolated to limit structure-borne noise and vibration transmitted to adjacent occupied spaces.
+### Distribution piping shall be supported as required by [[sync/hangers-and-supports]], at spacing not greater than the governing piping code or the modular system manufacturer requires for the material and size.
+### A modular aluminum or polyethylene system shall be supported with the hangers and at the spacing its manufacturer publishes, and the piping shall be free to move at its expansion fittings.
+
+### Distribution piping shall be identified with pipe markers and valve tags as required by [[sync/mechanical-identification]].
+
+### Piping between the compressor discharge and the aftercooler that can be touched from a floor, platform, or stair shall be insulated or guarded for personnel protection.
+
+### Penetrations of fire-resistance-rated construction shall be firestopped as required by [[sync/firestopping]].
+
+### Buried distribution piping shall be of a material rated for burial, shall be coated or wrapped where it is steel, and shall be installed below [[parameter: frost-depth]] or pitched to a drain in heated space.
+
+## Connections to Other Systems {toc}
+
+### The branch to each sprinkler riser that the system supplies with supervisory air shall be provided with an isolation valve under this standard, and the air maintenance device, the check valve, and the connection to the riser shall be as required by [[sync/dry-pipe-fire-sprinkler-systems]] or [[sync/pre-action-and-deluge-sprinkler-systems]].
+
+### Where the system supplies sprinkler supervisory air, the branch shall be taken upstream of any valve that is closed to shut down the shop air, and the air delivered at the branch shall meet the drying requirement the sprinkler standard states for the coldest space the sprinkler piping serves.
+
+### Where the system supplies pulse-jet cleaning air, the branch to each collector shall deliver air at the pressure dew point and the pressure that [[sync/dust-and-fume-collection]] requires at the collector, and the regulation at the collector is furnished under that standard.
+
+### The system shall not be connected to any medical gas, medical air, dental air, instrument air serving patient care, oxygen, or medical vacuum system, and no outlet of this system shall be installed in a patient care area with a terminal that accepts a medical gas connector.
+
+### General-service air is not made, monitored, or alarmed to NFPA 99, and a cross-connection between it and a patient system is the failure the NFPA 99 verification protocol exists to find. The source for every patient gas is furnished under [[sync/medical-gas-systems]]. {note}
+
+### No outlet of this system shall be used to supply a respirator or other respiratory protection.
+
+# Monitoring and Alarms {toc}
+
+## Header pressure regulation downstream of the receiver shall be as indicated in the datasheet.
+
```datasheet
−label: Compressor vibration isolation
+label: Header Pressure Regulation
type: radio
options:
− - Spring isolators (over 10 hp)
− - Neoprene pads (10 hp and under)
−default: Spring isolators (over 10 hp)
+ - "None: compressor control band sets the header pressure"
+ - "Pressure/flow controller downstream of a dry receiver"
```
−## Untreated compressors are a chronic source of complaints in occupied buildings because vibration travels through the slab and piping into walls and ceilings. Isolation at the machine and at every pipe connection interrupts that path. {note}
+## Without regulation the header rides the compressor's control band, and every outlet sees the top of the band most of the time, which is pressure every unregulated tool and every leak consumes. A pressure/flow controller holds the header a few psi above what the farthest outlet needs and stores the band above it in the dry receiver, so the plant stores energy instead of spending it; it needs the dry receiver and the band to work with. {note}
−## Spring vibration isolators shall be provided under each compressor rated above 10 hp.
+## The alarms transmitted to the building automation system or annunciated locally shall be as indicated in the datasheet.
−## Flexible pipe connectors not less than 18 in. long shall be installed at all compressor air connections.
+```datasheet
+label: System Alarms
+type: checkbox
+options:
+ - "Compressor common alarm"
+ - "Compressor shutdown"
+ - "Low header pressure"
+ - "High dryer outlet dew point"
+ - "High dryer outlet temperature"
+ - "Filter high differential pressure"
+ - "Condensate drain failure"
+ - "Oil-water separator service required"
+default:
+ - "Compressor common alarm"
+ - "Low header pressure"
+```
−## The flexible connector decouples the rigid distribution piping from the vibrating compressor so that pulsation and vibration are not transmitted into the building piping. {note}
+## A low header pressure alarm is the one that reports the plant has lost the race with demand or a leak, and it is set below the lag compressor's start pressure so that it reports a condition the sequencing could not correct. A dew point alarm is the only way a wet dryer is found before the outlets find it. {note}
−# Testing {toc}
+## Where the sprinkler supervisory air or the control air supplied by this system keeps a life-safety or building system in service, low header pressure shall be transmitted as a supervisory signal to the system that depends on it.
−## The distribution piping shall be pressure-tested after installation and before concealment or insulation.
+## The metering furnished for the plant shall be as indicated in the datasheet.
−## Testing before the piping is buried, insulated, or enclosed allows leaks to be found and corrected while joints are still accessible. {note}
+```datasheet
+label: Plant Metering
+type: checkbox
+options:
+ - "Flow meter at the treatment train outlet"
+ - "Power meter on the compressor feeder"
+ - "Dew point transmitter at the dryer outlet"
+ - "Header pressure transmitter to the building automation system"
+```
−## Steel distribution piping shall be hydrostatically tested at 1.5 times MAWP in accordance with ASME B31.1, or pneumatically leak-tested at 110% of operating pressure with soap-bubble inspection of all joints where a pneumatic test is approved.
+## Compressed air is bought by the kilowatt-hour and used by the cubic foot, and a plant with a flow meter and a power meter knows its specific power and knows when a leak has appeared; a plant without them knows only that the compressor runs. {note}
+# Installation {toc}
+
+## Compressors, dryers, and receivers shall be installed level on a housekeeping pad, with the service clearance the manufacturer publishes on every side that is serviced and with the clearance to remove the airend, the motor, and the cooler.
+
+## A compressor room that is sized to the equipment footprint is serviced by removing the equipment. The clearance that matters is the clearance to pull the motor and the cooler, and it is the clearance the drawings most often omit. {note}
+
+## Each compressor shall be connected to the distribution piping through a flexible connector rated for the discharge pressure and temperature, with the piping independently supported so that no load is carried by the compressor connection.
+
+## External vibration isolation of compressors shall be as required by [[sync/vibration-isolation-and-seismic-restraint]], and the manufacturer's internal isolation of a packaged compressor shall not be taken as satisfying that requirement.
+
+## Mains shall be pitched in the direction of flow, with a drip leg and drain at each low point and at the end of each main.
+
+## Pipe ends shall be capped whenever work stops, and the piping shall be kept free of cutting debris, thread chips, and sealant before it is closed.
+
+## Piping shall be blown clear with dry compressed air before the treatment train, the outlets, and any connected system are connected.
+
+## Scale and debris left in the pipe arrive at the first orifice downstream on the first day of service, and the orifices downstream are the regulators, the drains, the instruments, and the dust collector valves. {note}
+
+## Modular piping shall be cut, deburred, and assembled with the tools and to the insertion depth the system manufacturer requires, and each joint shall be marked to show full insertion.
+
+## Each compressor, dryer, receiver, and separator shall be labeled with its equipment designation from the equipment schedule, and each isolation valve shall be tagged as required by [[sync/mechanical-identification]].
+
+# Testing and Startup {toc}
+
+## Pressure Test {toc}
+
+### Each section of distribution piping shall be pressure tested after installation and before it is concealed, insulated, or connected to equipment, by the method indicated in the datasheet.
+
```datasheet
−label: Piping test method
+label: Piping Pressure Test Method
type: radio
options:
− - Hydrostatic at 1.5× MAWP (ASME B31.1)
− - Pneumatic at 110% operating pressure, soap-bubble inspection
−default: Pneumatic at 110% operating pressure, soap-bubble inspection
+ - "Pneumatic test with air or nitrogen"
+ - "Hydrostatic test"
+default: "Pneumatic test with air or nitrogen"
```
−## The receiver pressure-relief device shall be tested and certified to relieve at its set pressure before the system is placed in service.
+### A pneumatic test uses the fluid the pipe will carry, leaves nothing to dry out, and stores energy in the test medium, so the governing code limits its pressure and its rate of pressurization and the test area is cleared while it is held; it is the test nearly every compressed air system gets, which is why it carries the default. A hydrostatic test stores little energy and leaves water in piping that then has to be dried before the dryer can hold its dew point, and it is the test for a system whose stored energy under a pneumatic test the code or the Owner will not accept. {note}
−## The delivered air dew point shall be verified at the dryer outlet to confirm it meets the specified pressure dew point.
+### The test pressure shall be the multiple of the system design pressure indicated in the datasheet.
−## Dew point is the single most common air-quality shortfall and is easily measured at startup with an inline hygrometer; verifying it confirms the dryer is performing to specification. {note}
+```datasheet
+label: Test Pressure as a Multiple of Design Pressure
+type: range
+unit: '× design pressure'
+derived: "the governing piping code indicated in the datasheet and the test method"
+min: 1.1
+max: 1.5
+setpoints: [1.1, 1.2, 1.25, 1.5]
+default: derived
+```
−## The delivered air purity shall be verified against the specified ISO 8573-1 class using the test methods of ISO 8573-2 through 8573-9 where the application requires documented purity.
+### The test shall be held for not less than the time indicated in the datasheet, with no loss of pressure other than that attributable to a change in temperature.
−# Installation {toc}
+```datasheet
+label: Pressure Test Hold Time
+type: range
+unit: hours
+min: 0.5
+max: 24
+setpoints: [0.5, 1, 2, 4, 8, 24]
+```
−## Equipment shall be installed level, anchored, and with the manufacturer's required service clearances.
+### The governing code sets the shortest hold at which a joint is examined under pressure, and a longer hold is what finds the slow leak that a short hold reads as a temperature change. Twenty-four hours with the temperature recorded at both ends is the hold that finds the leaks a plant would otherwise spend its life feeding. {note}
−## Adequate clearance around compressors, dryers, and filters is required for filter changes, oil service, and coil cleaning; crowding the equipment guarantees deferred maintenance. {note}
+### Compressors, dryers, filters, receivers, regulators, and gauges shall be isolated from the pressure test, and the test pressure shall not be applied to any component whose rating it exceeds.
−## Distribution piping shall be installed with a uniform slope toward drip legs so that condensate drains to a collection point and does not pool in the line.
+### Joints found leaking shall be remade, not sealed from the outside, and the section shall be retested in full at the Contractor's cost.
−## Mains are pitched in the direction of flow and branch takeoffs are taken from the top of the main, so condensate runs to drip legs rather than being carried into the branch. {note}
+## Leakage Survey {toc}
−## Branch connections shall be taken from the top of the distribution main.
+### After the system is placed under its operating pressure and before the outlets are put into service, the leakage of the whole system shall be measured by timing the pressure decay with the outlets closed or by the compressor loaded-time method, and shall not exceed the share of installed capacity indicated in the datasheet.
−## Drip legs with drain valves shall be installed at the low points of the distribution system and at the base of risers.
+```datasheet
+label: Maximum System Leakage
+type: range
+unit: '% of installed capacity'
+min: 0
+max: 25
+setpoints: [0, 2, 5, 10, 15, 20, 25]
+```
−## Pipe supports shall be spaced in accordance with the applicable piping code for the pipe material and size.
+### A new system on welded or modular joints measures in the low single digits, and a threaded system in the range of five to ten; a plant whose leakage is above a tenth of its capacity is running a compressor for its leaks. The limit is the acceptance criterion for the joining method the plant bought. {note}
−## Each piece of equipment and each isolation valve shall be labeled to identify its service and the equipment it serves.
+### Leaks shall be located with an ultrasonic detector or a leak-detection solution, and each leak found shall be repaired and the survey repeated until the limit is met.
−# Delivery, Storage, and Handling {toc}
+## Startup and Purity Verification {toc}
−## Equipment and piping shall be delivered in the manufacturer's packaging and protected from weather, dust, and physical damage until installation.
+### Each compressor and dryer shall be started by the manufacturer's authorized representative, who shall set the controls, confirm the rotation, lubricant, and cooling, record the as-left settings, and issue the startup report.
−## Pipe ends and equipment connections capped at the factory must stay capped until connected, because debris that enters open piping migrates to filters and valves during startup.
+### The pressure dew point at the outlet of each dryer shall be measured at startup with the plant at not less than half its design flow, and shall meet the water class indicated in the datasheet.
−## Pipe and fitting openings shall remain capped or plugged until the piping is connected.
+### The purity verification tests performed shall be as indicated in the datasheet.
−## Compressors and receivers shall be stored upright.
+```datasheet
+label: Purity Verification Tests
+type: checkbox
+options:
+ - "Pressure dew point at the dryer outlet by ISO 8573-3"
+ - "Particle count by ISO 8573-4"
+ - "Oil aerosol by ISO 8573-2"
+ - "Oil vapor by ISO 8573-5"
+ - "Viable microbiological content by ISO 8573-7"
+default:
+ - "Pressure dew point at the dryer outlet by ISO 8573-3"
+```
−## Compressors and receivers shall not be subjected to loads or impacts that could damage the pressure vessel or rotating assembly.
+### Dew point is measured in minutes with an instrument the startup technician carries and is the one contaminant that is verified on nearly every plant. A particle count and an oil measurement take a laboratory or a specialist, and are verified where the class was tight enough to have cost something to reach, which is the oil Class 1 and Class 0 and the particle Class 1 and Class 2 that a laboratory, a food-contact, or a paint service asked for. {note}
+### Where a purity test fails, the Contractor shall correct the cause and repeat the test, and the cost of the correction and the retest shall be borne by the Contractor.
+
+### The sequencing, the alarms, and the building automation system interface shall be demonstrated by producing each condition and recording its receipt.
+
+### The Contractor shall provide instruction to the Owner's operating staff for not less than the time indicated in the datasheet, covering the compressor controls, the dryer and filter service, the drains and separator, and the sequencing.
+
+```datasheet
+label: Operator Instruction Duration
+type: range
+unit: hours
+min: 0
+max: 16
+setpoints: [0, 2, 4, 8, 16]
+default: 4
+```
+
+# Delivery, Storage, and Handling {toc}
+
+## Compressors, dryers, and receivers shall be delivered in the manufacturer's packaging, stored upright under cover, and protected from weather, dust, and impact until installed.
+
+## Pipe, fittings, and modular piping components shall be delivered with their ends capped and stored off the ground under cover, and the caps shall remain in place until the joint is made.
+
+## A refrigerated dryer shall be stored and moved upright, and shall not be started until it has stood upright for the time its manufacturer requires after transport.
+
# Warranty {toc}
−## The compressor and air treatment equipment shall be warranted against defects in materials and workmanship for the period specified.
+## Each compressor package, dryer, and receiver shall be warranted against defects in materials and workmanship for the period indicated in the datasheet, beginning at substantial completion.
```datasheet
−label: Equipment warranty period
−type: select
+label: Equipment Warranty Period
+type: range
unit: years
−options:
− - "1"
− - "2"
− - "5"
−default: "2"
+min: 1
+max: 10
+setpoints: [1, 2, 3, 5, 10]
+default: 1
```
−## Extended airend or compression-element warranties offered by the manufacturer should be obtained where available.
+## The extended warranty on the compression element shall be for not less than the period indicated in the datasheet.
−## The compression element (airend on a rotary screw, pump on a reciprocating machine) is the highest-value component and many manufacturers offer extended coverage on it; capturing that coverage at purchase protects the largest replacement cost. {note}
+```datasheet
+label: Compression Element Extended Warranty
+type: range
+unit: years
+min: 0
+max: 10
+setpoints: [0, 2, 5, 10]
+```
−# Spare Parts {toc}
+## One year is the base warranty a compressor package is sold with, which is why it carries the default. The airend of a rotary screw and the pump of a reciprocating compressor are the costliest parts to replace, and manufacturers sell extended coverage on them, usually conditioned on the use of their lubricant and filters at their intervals; the extended term is bought at purchase and is not available afterward. {note}
−## A complete set of consumable spare parts shall be furnished for first-year maintenance.
+## Where a warranty repair is made, the repaired component shall be warranted for the remainder of the original term or for one year from the repair, whichever is longer.
−## Compressors and dryers consume filters, separators, and lubricant on a regular schedule. Delivering a first-year set with the equipment prevents the system from running on degraded consumables while replacements are procured. {note}
+# Spare Parts {toc}
−## The following spare parts shall be furnished with the equipment:
−- One complete set of intake and oil filters per compressor
−- One complete set of coalescing and particulate filter elements
−- One oil-water separator cartridge where applicable
−- One set of compressor lubricant for the first oil change
+## The Contractor shall deliver the spare parts indicated in the datasheet to the Owner before the system is accepted, and shall obtain a signed receipt for them.
```datasheet
−label: Spare parts to be furnished
+label: Spare Parts to Be Furnished
type: checkbox
options:
− - Intake and oil filter set (per compressor)
− - Coalescing and particulate filter elements
− - Oil-water separator cartridge
− - Compressor lubricant (first change)
+ - "Intake filter element for each compressor"
+ - "Lubricant and oil filter for the first change of each oil-injected compressor"
+ - "Air-oil separator element for each oil-injected rotary screw compressor"
+ - "One set of filter elements for each treatment train filter"
+ - "Oil-water separator cartridge"
+ - "One spare condensate drain of each type installed"
+ - "Desiccant charge for one refill of each regenerative dryer"
+ - "Coupler plugs, one per outlet"
+default:
+ - "Intake filter element for each compressor"
+ - "Lubricant and oil filter for the first change of each oil-injected compressor"
+ - "One set of filter elements for each treatment train filter"
```
+
+## Spare parts shall be the same make and model as the installed items, delivered in their original packaging, and labeled with the equipment they serve.