Corpus sync: neutrality remakes, note hygiene, datasheet relocation, transformer-split cross-refs
---
title: Common Work Results for Mechanical
…50 unchanged lines
### The mechanical installation shall comply with the edition of the International Mechanical Code adopted by the Authority Having Jurisdiction at the project location, together with all state and local amendments in force.
−### Pressure piping shall comply with the edition of ASME B31.9 (Building Services Piping) adopted or referenced by the Authority Having Jurisdiction.
−
−### The Contractor shall confirm the adopted IMC and ASME B31.9 editions and applicable amendments with the Authority Having Jurisdiction before commencing rough-in, and shall notify the Engineer of Record in writing of any amendment that conflicts with the contract documents.
−
−### The edition assumed in design shall be reconciled against the locally adopted edition before specifications are issued for construction and shall not be presumed to be the most recent publication.
−
−### Many jurisdictions lag the published model codes by one or more cycles; confirming the adopted edition before specifications are finalized prevents code conflicts from surfacing during permit review. {note}
−
```datasheet
label: Governing Mechanical Code Edition
…7 unchanged lines
```
+### Pressure piping shall comply with the edition of ASME B31.9 (Building Services Piping) adopted or referenced by the Authority Having Jurisdiction.
+
```datasheet
label: Governing Pressure Piping Code (ASME B31.9 Edition)
…6 unchanged lines
```
−## Design Fluids and Temperatures {toc}
+### The Contractor shall confirm the adopted IMC and ASME B31.9 editions and applicable amendments with the Authority Having Jurisdiction before commencing rough-in, and shall notify the Engineer of Record in writing of any amendment that conflicts with the contract documents.
−### The basis-of-design fluid type and design supply and return temperatures of each hydronic and steam system shall be declared here and shall govern all downstream sections including boilers, chillers, coils, heat exchangers, and pumps.
+### The edition assumed in design shall be reconciled against the locally adopted edition before specifications are issued for construction and shall not be presumed to be the most recent publication.
−### Where a system uses a glycol solution rather than water, the glycol type and volumetric concentration shall be declared so that downstream sections can apply the correct freeze protection, derating, and fluid properties.
+### Many jurisdictions lag the published model codes by one or more cycles; confirming the adopted edition before specifications are finalized prevents code conflicts from surfacing during permit review. {note}
−### Declaring design supply water temperatures once prevents the common coordination failure in which the boiler section sizes for one supply temperature while the coil section selects for another, and the mismatch is not caught until equipment submittals arrive. {note}
+## Design Fluids and Temperatures {toc}
+### The basis-of-design fluid type and design supply and return temperatures of each hydronic and steam system shall be declared here and shall govern all downstream sections including boilers, chillers, coils, heat exchangers, and pumps.
+
```datasheet
label: Hot Water Heating Supply / Return Temperature
…29 unchanged lines
```
+### Where a system uses a glycol solution rather than water, the glycol type and volumetric concentration shall be declared so that downstream sections can apply the correct freeze protection, derating, and fluid properties.
+
```datasheet
label: Glycol Concentration (where glycol is used)
…7 unchanged lines
```
+### Declaring design supply water temperatures once prevents the common coordination failure in which the boiler section sizes for one supply temperature while the coil section selects for another, and the mismatch is not caught until equipment submittals arrive. {note}
+
## System Operating Pressure {toc}
### The design working pressure of each piping system shall be declared in the basis of design before any valve, gage, or pressure-rated component is procured, and shall govern the pressure class of all components in that system.
−### All valves, fittings, flanges, and specialties in a system shall carry a pressure-temperature rating equal to or greater than the system design working pressure at the system design temperature.
−
−### Systems whose design pressure approaches the ASME B31.9 scope limit of 250 PSI shall be reviewed against the B31.9 applicability criteria before the code basis is fixed.
−
−### Building services piping under ASME B31.9 is limited to water systems not exceeding 250 PSI; systems near this threshold may fall outside B31.9 scope and require a different pressure piping code to govern the installation. {note}
−
```datasheet
label: Hydronic System Design Working Pressure
…6 unchanged lines
```
+### All valves, fittings, flanges, and specialties in a system shall carry a pressure-temperature rating equal to or greater than the system design working pressure at the system design temperature.
+
+### Systems whose design pressure approaches the ASME B31.9 scope limit of 250 PSI shall be reviewed against the B31.9 applicability criteria before the code basis is fixed.
+
+### Building services piping under ASME B31.9 is limited to water systems not exceeding 250 PSI; systems near this threshold may fall outside B31.9 scope and require a different pressure piping code to govern the installation. {note}
+
# Submittals {toc}
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### To the greatest extent practicable, each general-duty valve type shall be furnished by a single manufacturer across the project so that trim, operators, and repair parts are interchangeable.
−### Standardizing a valve type to one manufacturer reduces the spare-parts inventory the owner must carry and avoids field confusion between visually similar valves with different internal trim. {note}
+### Standardizing a valve type to one manufacturer reduces the spare-parts inventory the owner must carry and avoids field confusion between visually similar valves with different internal trim.
# Common Motor Requirements {toc}
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### Motors 1/2 horsepower and smaller shall be permitted to be single-phase, 115V or 208–230V.
+```datasheet
+label: Single-Phase Fractional Motor Voltage (≤ 1/2 hp)
+type: radio
+options:
+ - "115V, 1Φ, 60 Hz"
+ - "208–230V, 1Φ, 60 Hz"
+default: "115V, 1Φ, 60 Hz"
+```
+
### Motors larger than 1/2 horsepower shall be three-phase at the project basis-of-design voltage.
### Three-phase motors shall be selected for the declared building distribution voltage, and motors 5 horsepower and larger on a 480V system shall be rated 460V.
−### The motor nameplate voltage shall be a single declared value, not a slash-rated range left to the installer.
−
−### The actual system voltage shall be specified on the motor schedule so that feeders are sized for the operating voltage and not defaulted to the lowest value in a multi-voltage range.
−
−### Leaving the wiring voltage unspecified on a slash-rated motor invites the contractor to default to the lowest value in the range, which can overload feeders and foreclose future voltage upgrades. {note}
−
```datasheet
label: Three-Phase Motor Nameplate Voltage
…7 unchanged lines
```
−```datasheet
−label: Single-Phase Fractional Motor Voltage (≤ 1/2 hp)
−type: radio
−options:
− - "115V, 1Φ, 60 Hz"
− - "208–230V, 1Φ, 60 Hz"
−default: "115V, 1Φ, 60 Hz"
−```
+### The motor nameplate voltage shall be a single declared value, not a slash-rated range left to the installer.
+### The actual system voltage shall be specified on the motor schedule so that feeders are sized for the operating voltage and not defaulted to the lowest value in a multi-voltage range.
+
+### Leaving the wiring voltage unspecified on a slash-rated motor invites the contractor to default to the lowest value in the range, which can overload feeders and foreclose future voltage upgrades. {note}
+
## Efficiency {toc}
### Polyphase motors 1 horsepower and larger shall meet the minimum nominal full-load efficiency of NEMA Premium (IE3) per NEMA MG 1, in compliance with ASHRAE 90.1.
−### Specifying standard-efficiency motors at 1 horsepower and larger is a code violation in jurisdictions that have adopted ASHRAE 90.1; NEMA Premium is the minimum for new HVAC installations. {note}
−
```datasheet
label: Polyphase Motor Efficiency Class (≥ 1 hp)
…4 unchanged lines
```
+### Specifying standard-efficiency motors at 1 horsepower and larger is a code violation in jurisdictions that have adopted ASHRAE 90.1; NEMA Premium is the minimum for new HVAC installations. {note}
+
## Enclosure {toc}
…2 unchanged lines
### All other motors shall be totally enclosed fan-cooled.
−### Motors in spaces classified by the mechanical Engineer as wet or damp locations shall be totally enclosed fan-cooled at minimum, and shall not be open drip-proof.
−
−### Open drip-proof enclosures are not suitable for washdown or high-humidity spaces; defaulting to ODP in any space that may be wet leads to premature motor failure, so TEFC is the minimum where the space classification is anything other than clean and dry. {note}
−
```datasheet
label: Motor Enclosure Type
…6 unchanged lines
```
+### Motors in spaces classified by the mechanical Engineer as wet or damp locations shall be totally enclosed fan-cooled at minimum, and shall not be open drip-proof.
+
+### Open drip-proof enclosures are not suitable for washdown or high-humidity spaces; defaulting to ODP in any space that may be wet leads to premature motor failure, so TEFC is the minimum where the space classification is anything other than clean and dry. {note}
+
## Service Factor and Insulation {toc}
…2 unchanged lines
### General-purpose motors not driven by a variable frequency drive shall have Class F insulation rated for 155°C.
−### Motors intended for operation on a variable frequency drive shall be rated inverter-duty per NEMA MG 1 Part 31, with insulation system suitable for the drive switching frequency.
−
−### Standard motors driven by a VFD can fail prematurely from voltage stress above certain switching frequencies; specifying NEMA MG 1 Part 31 inverter-duty rating for all VFD-driven motors prevents this failure mode. {note}
−
```datasheet
label: Insulation Class
…5 unchanged lines
```
+### Motors intended for operation on a variable frequency drive shall be rated inverter-duty per NEMA MG 1 Part 31, with insulation system suitable for the drive switching frequency.
+
```datasheet
label: Inverter-Duty Rating (for VFD-driven motors)
…5 unchanged lines
```
+### Standard motors driven by a VFD can fail prematurely from voltage stress above certain switching frequencies; specifying NEMA MG 1 Part 31 inverter-duty rating for all VFD-driven motors prevents this failure mode. {note}
+
# General-Duty Valves for HVAC Piping {toc}
…6 unchanged lines
### Isolation valves 2 inches and smaller shall be full-port bronze ball valves, and isolation valves 2-1/2 inches and larger shall be lug- or wafer-pattern butterfly valves with ductile-iron body, EPDM seat, and stainless disc.
−### Butterfly valves 6 inches and smaller shall be furnished with lever handles, and butterfly valves 8 inches and larger shall be furnished with gear operators.
−
−### Cast or ductile iron shall be used for valve bodies above 2 inches; bronze bodies are not permitted at 2-1/2 inches and larger.
−
−### Bronze valves are commonly stocked only through 2 inches; specifying bronze above that size results in substitution requests or long-lead special orders. {note}
−
```datasheet
label: Isolation Valve Type, 2 in. and Smaller
…15 unchanged lines
```
+### Butterfly valves 6 inches and smaller shall be furnished with lever handles, and butterfly valves 8 inches and larger shall be furnished with gear operators.
+
+### Cast or ductile iron shall be used for valve bodies above 2 inches; bronze bodies are not permitted at 2-1/2 inches and larger.
+
+### Bronze valves are commonly stocked only through 2 inches; specifying bronze above that size results in substitution requests or long-lead special orders. {note}
+
## Valve Function {toc}
…30 unchanged lines
# Expansion Fittings and Loops {toc}
−## Thermal growth and contraction of HVAC piping must be accommodated so that the movement is not transmitted to equipment connections, branch takeoffs, or building structure as damaging stress. {note}
+## Thermal growth and contraction of HVAC piping must be accommodated so that the movement is not transmitted to equipment connections, branch takeoffs, or building structure as damaging stress.
## Movement Accommodation Method {toc}
…3 unchanged lines
### Expansion loops and pipe offsets shall be the preferred method where routing and space permit, and packed or bellows expansion joints shall be used where space does not permit a loop.
−### Expansion loops have no packing or bellows to fail and require no maintenance, so they are preferred wherever the routing affords room; expansion joints are reserved for constrained locations and accept a maintenance obligation in exchange for compactness. {note}
−
```datasheet
label: Primary Thermal Movement Accommodation
…7 unchanged lines
```
+### Expansion loops have no packing or bellows to fail and require no maintenance, so they are preferred wherever the routing affords room; expansion joints are reserved for constrained locations and accept a maintenance obligation in exchange for compactness. {note}
+
## Anchors and Guides {toc}
…14 unchanged lines
### Sleeve sizing shall account for the insulation thickness and the modular seal clearance, not the bare-pipe outside diameter shown on structural drawings.
−### Sleeve sizing shall be reconciled against the insulated pipe outside diameter plus the required seal annular clearance before sleeves are set, not against the bare-pipe size shown on structural drawings.
−
−### Structural drawings commonly show bare-pipe sleeve sizes; once insulation thickness and seal clearance are added the sleeve is undersized if not reviewed before placement. {note}
−
```datasheet
label: Sleeve Clearance Basis
…6 unchanged lines
```
+### Sleeve sizing shall be reconciled against the insulated pipe outside diameter plus the required seal annular clearance before sleeves are set, not against the bare-pipe size shown on structural drawings.
+
+### Structural drawings commonly show bare-pipe sleeve sizes; once insulation thickness and seal clearance are added the sleeve is undersized if not reviewed before placement. {note}
+
## Sleeve Seals {toc}
…17 unchanged lines
### Penetrations of fire-resistance-rated walls, floors, and ceilings shall be firestopped with a listed firestop system tested to ASTM E814 and providing an hourly rating equal to the rating of the assembly penetrated, and not less than 1 hour.
−### The firestop system installed at each rated penetration shall be a listed assembly appropriate to the penetrant, sleeve, and annular dimensions at that condition.
−
−### The listed firestop system shall be identified by penetration condition in the firestop submittal, including penetrant type, sleeve material and inside diameter, and annular dimension, so that the installed assembly matches the tested configuration.
−
−### Omitting firestopping from the common work section leaves firestop submittals uncoordinated across mechanical, electrical, and plumbing trades and invites incompatible product combinations at a shared penetration. {note}
−
```datasheet
label: Floor-to-Floor Penetration Firestop Rating
…7 unchanged lines
```
+### The firestop system installed at each rated penetration shall be a listed assembly appropriate to the penetrant, sleeve, and annular dimensions at that condition.
+
+### The listed firestop system shall be identified by penetration condition in the firestop submittal, including penetrant type, sleeve material and inside diameter, and annular dimension, so that the installed assembly matches the tested configuration.
+
+### Omitting firestopping from the common work section leaves firestop submittals uncoordinated across mechanical, electrical, and plumbing trades and invites incompatible product combinations at a shared penetration. {note}
+
# Meters and Gages {toc}
…6 unchanged lines
### Gage scale range shall be approximately twice the maximum working pressure so that the normal operating pressure falls within the middle third of the scale.
−### A gage whose normal reading sits at the very bottom or top of its scale cannot be read accurately; selecting the range at roughly twice working pressure keeps the operating point in the legible middle third. {note}
−
```datasheet
label: Pressure Gage Range
…8 unchanged lines
```
+### A gage whose normal reading sits at the very bottom or top of its scale cannot be read accurately; selecting the range at roughly twice working pressure keeps the operating point in the legible middle third. {note}
+
+### The pressure gage dial size shall be specified for each application, sized for legibility at the installation location.
+
```datasheet
label: Pressure Gage Dial Size
…11 unchanged lines
### Adjustable-angle bimetal or digital thermometers shall be installed at equipment inlets and outlets and where required to read fluid temperature, with a scale range appropriate to the service.
−### Every thermometer in a piping system shall be installed in a separable thermowell so that it can be removed and replaced without draining the system.
−
−### Thermowells shall be provided at every thermometer location so that thermometers can be removed and replaced without draining the system.
−
−### A thermometer installed without a thermowell cannot be serviced unless the system is drained; specifying the thermowell as part of the common instrument installation prevents this maintenance constraint. {note}
−
```datasheet
label: Thermometer Type
…16 unchanged lines
```
−## Test Plugs {toc}
+### Every thermometer in a piping system shall be installed in a separable thermowell so that it can be removed and replaced without draining the system.
−### Self-sealing test plugs rated for the system pressure and temperature shall be installed at equipment inlets and outlets and at coil connections to provide temperature and pressure access for balancing without draining the system.
+### Thermowells shall be provided at every thermometer location so that thermometers can be removed and replaced without draining the system.
−### Self-sealing test plugs shall be specified at all equipment inlet and outlet connections and at all coil connections.
+### A thermometer installed without a thermowell cannot be serviced unless the system is drained; specifying the thermowell as part of the common instrument installation prevents this maintenance constraint. {note}
−### Omitting test plugs from the common work section leaves the balancing technician without pressure and temperature access ports; adding them during balancing generates change orders. {note}
+## Test Plugs {toc}
+### Self-sealing test plugs rated for the system pressure and temperature shall be installed at equipment inlets and outlets and at coil connections to provide temperature and pressure access for balancing without draining the system.
+
```datasheet
label: Test Plug Service Rating
…6 unchanged lines
```
+### Self-sealing test plugs shall be specified at all equipment inlet and outlet connections and at all coil connections.
+
+### Omitting test plugs from the common work section leaves the balancing technician without pressure and temperature access ports; adding them during balancing generates change orders. {note}
+
# Equipment Supports and Seismic Restraint {toc}
…10 unchanged lines
### The seismic design category of the project shall be declared in the basis of design, and seismic restraint of mechanical equipment shall be provided where required by ASCE 7 Chapter 13 for that category.
−### In Seismic Design Categories D, E, and F, mechanical components shall be braced and anchored per ASCE 7 Chapter 13.
−
−### In Seismic Design Category C, equipment shall be anchored per the importance factor and weight thresholds of ASCE 7.
−
−### The contract documents shall assign responsibility for seismic restraint design, whether to the structural Engineer of Record, to delegated contractor design, or to pre-engineered listed restraint systems.
−
−### The assignment of seismic restraint design responsibility shall be made explicit in the contract documents and shall not be left to be resolved through RFIs in the field.
−
−### Failing to assign seismic restraint design responsibility is a recurrent source of RFIs and schedule delays in Seismic Design Category C and above. {note}
−
−### Vibration isolation bases, inertia pads, and seismic snubbers themselves are governed by [[sync/vibration-isolation-and-seismic-restraint]]; this section sets only the threshold at which restraint is required. {note}
−
```datasheet
label: Seismic Design Category
…10 unchanged lines
```
+### In Seismic Design Categories D, E, and F, mechanical components shall be braced and anchored per ASCE 7 Chapter 13.
+
+### In Seismic Design Category C, equipment shall be anchored per the importance factor and weight thresholds of ASCE 7.
+
```datasheet
label: Component Importance Factor (Ip)
…5 unchanged lines
```
+### The contract documents shall assign responsibility for seismic restraint design, whether to the structural Engineer of Record, to delegated contractor design, or to pre-engineered listed restraint systems.
+
```datasheet
label: Seismic Restraint Design Responsibility
…5 unchanged lines
```
+### The assignment of seismic restraint design responsibility shall be made explicit in the contract documents and shall not be left to be resolved through RFIs in the field.
+
+### Failing to assign seismic restraint design responsibility is a recurrent source of RFIs and schedule delays in Seismic Design Category C and above. {note}
+
+### Vibration isolation bases, inertia pads, and seismic snubbers themselves are governed by [[sync/vibration-isolation-and-seismic-restraint]]; this section sets only the threshold at which restraint is required. {note}
+
# Cutting and Patching {toc}
…14 unchanged lines
## Before systems are handed to the balancing contractor and the owner, the installing contractor must prove the piping holds pressure and the rotating equipment runs correctly. This field acceptance test is distinct from formal balancing. {note}
−## The field acceptance testing in this section is distinct from the testing, adjusting, and balancing governed by [[sync/testing-adjusting-and-balancing]]; both are required and shall not be conflated. {note}
+## The field acceptance testing in this section is distinct from the testing, adjusting, and balancing governed by [[sync/testing-adjusting-and-balancing]]; both are required and shall not be conflated.
## Pressure Testing {toc}
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### Spare parts shall be the products of the same manufacturers as the installed components so that they are interchangeable with the installed work.