Refrigerant Piping

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−---

−title: Refrigerant Piping

−category: Mechanical / Piping & Pumps

−toc_depth: 3

−description: >

− When to use: Field-installed refrigerant piping (interconnecting tubing, or "line sets") serving split-system air conditioners and heat pumps, variable refrigerant flow (VRF) systems, and direct-expansion (DX) coils in commercial, institutional, and light-industrial buildings. Covers air-conditioning and refrigeration (ACR) copper tube selection by temper and type, brazed and refrigerant-rated mechanical joints, line sizing and routing within manufacturer length and lift limits, oil-return provisions and traps, closed-cell elastomeric insulation, A2L mildly-flammable refrigerant safety provisions under ASHRAE 15 and 15.2 (refrigerant detection, ventilation interlock, charge and concentration limits), penetration sleeving and firestopping, and the complete pressure-test, evacuation, and charging sequence. Applicable to systems using R-410A and the lower-GWP A2L refrigerants (R-32, R-454B) now mandated under the EPA AIM Act Technology Transition Rule.

− Not intended for: Hydronic heating and cooling water piping (see [[sync/hydronic-piping]]); the air-conditioning and heat-pump equipment itself (see [[sync/variable-refrigerant-flow-systems]] and [[sync/split-system-air-conditioners]]); condensate drain piping; ammonia (R-717) industrial refrigeration and other systems governed by IIAR standards; supermarket CO2 (R-744) transcritical racks; or any refrigeration system with design temperatures below the ASME B31.5 scope. Factory-charged, factory-piped packaged equipment with no field refrigerant joints is excluded.

−---

−

−# Scope {toc}

−

−## This specification covers the materials, fabrication, installation, examination, testing, evacuation, and charging of field-installed refrigerant piping that interconnects the components of split-system, variable refrigerant flow (VRF), and direct-expansion (DX) air-conditioning and heat-pump systems. {note}

−

−## Extent of Work {toc}

−

−### The work includes the liquid, suction (vapor), and where applicable discharge and hot-gas lines; refrigerant specialties installed in the field piping; line insulation; pipe supports; sleeves and firestopping at penetrations; and the refrigerant safety provisions required for mildly flammable (A2L) refrigerants.

−

−### All work shall comply with ASME B31.5, Refrigeration Piping and Heat Transfer Components, ASHRAE 15 and ASHRAE 15.2 for refrigeration system safety, the adopted edition of the International Mechanical Code (IMC), and the requirements of the equipment manufacturer whose system the piping serves.

−

−## Why Refrigerant Piping Is Different {toc}

−

−### Refrigerant piping is a sealed, high-pressure system that carries a two-phase fluid and a small but critical quantity of compressor lubricating oil that must circulate with the refrigerant and return to the compressor. {note}

−

−### The interior of the tube is a working surface: any moisture, oxide scale, particulate, or non-condensable gas left inside becomes a permanent contaminant that degrades capacity, attacks the compressor, and shortens equipment life. {note}

−

−### The way the piping is brazed, pressure-tested, evacuated, and charged is as much a part of this standard as the materials themselves; a mechanically perfect installation that was brazed without a nitrogen purge, or charged without a proper evacuation, is a defective installation. {note}

−

−## Boundary of Work {toc}

−

−### The boundary of work under this standard is the refrigerant tubing and field-installed specialties from the service-valve or stub connection at the outdoor (condensing or heat-recovery) unit, through all interconnecting piping, branch joints, and headers, to the service-valve or stub connection at each indoor unit, fan-coil, or DX coil.

−

−### The air-conditioning and heat-pump equipment itself, its factory charge, and its internal piping are covered by the equipment standards [[sync/variable-refrigerant-flow-systems]] and [[sync/split-system-air-conditioners]]. {note}

−

−### Electrical power and control wiring between units is covered by the electrical standards, and condensate drainage from indoor units and coils is not part of this standard. {note}

−

−# Referenced Standards {toc}

−

−## Materials, fabrication, and installation shall comply with the latest adopted editions of the following standards and codes.

−

−| Standard | Title |

−|----------|-------|

−| ASME B31.5 | Refrigeration Piping and Heat Transfer Components |

−| ASME Sec. IX | Boiler and Pressure Vessel Code — Welding, Brazing, and Fusing Qualifications |

−| ASME B16.22 | Wrought Copper and Copper Alloy Solder-Joint Pressure Fittings |

−| ASME B16.50 | Wrought Copper and Copper Alloy Braze-Joint Pressure Fittings |

−| ASHRAE 15 | Safety Standard for Refrigeration Systems |

−| ASHRAE 15.2 | Safety Standard for Refrigeration Systems in Residential and Light-Commercial Applications |

−| ASHRAE 34 | Designation and Safety Classification of Refrigerants |

−| ASTM B280 | Seamless Copper Tube for Air Conditioning and Refrigeration Field Service (ACR) |

−| ASTM B88 | Seamless Copper Water Tube |

−| ASTM B819 | Seamless Copper Tube for Medical Gas Systems (where oxygen-clean tube is referenced) |

−| ASTM C534 | Preformed Flexible Elastomeric Cellular Thermal Insulation in Sheet and Tubular Form |

−| ASTM E84 | Surface Burning Characteristics of Building Materials (flame spread / smoke developed) |

−| AWS A5.8 | Specification for Filler Metals for Brazing and Braze Welding |

−| UL 60335-2-40 | Household and Similar Electrical Appliances — Particular Requirements for Electrical Heat Pumps, Air-Conditioners, and Dehumidifiers |

−| NFPA 70 | National Electrical Code (for refrigerant detection system and interlock wiring) |

−| IMC | International Mechanical Code (Refrigeration) |

−| MSS SP-58 | Pipe Hangers and Supports — Materials, Design, Manufacture, Selection, Application, and Installation |

−| EPA 40 CFR Part 84 | Technology Transition rule under the AIM Act (refrigerant GWP limits) |

−

−## Precedence of Conflicting Requirements {toc}

−

−### Where the contract documents, the adopted building or mechanical code, the equipment manufacturer's installation instructions, or a referenced standard conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.

−

−### The equipment manufacturer's published line-size, length, and elevation (lift) limits are mandatory and shall not be exceeded even where this standard or the drawings would otherwise permit it.

−

−# Submittals {toc}

−

−## Action Submittals {toc}

−

−### The Contractor shall submit the following for the Engineer's review and return before procurement and installation.

−### Submittals shall be complete and internally coordinated with the equipment manufacturer's installation requirements before any item is submitted.

−

−- Product data for ACR copper tube, showing the ASTM B280 designation, temper (hard-drawn or annealed), type, outside diameter and wall thickness by line, and confirmation that the tube is supplied cleaned, dehydrated, nitrogen-charged, and capped

−- Product data for all fittings and joints, including wrought copper braze-joint fittings (ASME B16.50) and any refrigerant-rated mechanical or press fittings proposed, with the manufacturer's pressure rating and refrigerant compatibility (including A2L listing where applicable)

−- Product data for brazing filler metal, showing the AWS A5.8 classification (BCuP or BAg series), composition, and flux requirement

−- Product data for refrigerant-line insulation, showing the ASTM C534 type/grade, wall thickness, thermal conductivity, water-vapor permeability, maximum service temperature, and ASTM E84 flame-spread and smoke-developed indices

−- Product data for field-installed refrigerant specialties (filter-driers, sight glasses, service valves, ball valves, line-set isolation or shutoff valves) where part of the field piping scope

−- Product data for the refrigerant detection system (RDS) sensors and the ventilation/shutoff interlock components where A2L mitigation is required, with the alarm set point relative to the lower flammability limit (LFL) and UL 60335-2-40 listing

−- A refrigerant piping coordination drawing set showing routing, line sizes, equivalent lengths, vertical separations (lifts and drops), oil-trap locations, branch/header locations, support locations, and penetration and firestop locations, coordinated against the manufacturer's maximum allowable pipe lengths and elevation differences

−- The equipment manufacturer's refrigerant piping design tables or selection software output documenting that the proposed line sizes and lengths are within the allowable limits for the specific equipment and refrigerant

−- Brazing procedure specifications (BPS) and procedure qualification records (PQR) per ASME Section IX, and brazer performance qualification records for all personnel who will braze on this project

−- A written pressure-test, evacuation, and charging plan describing the test medium, hold pressures, hold durations, vacuum target, decay-test criteria, charging method, and the sequence relative to insulation and closing of penetrations

−- An A2L refrigerant safety plan (where the system uses an A2L refrigerant) documenting the system refrigerant charge, the smallest occupied space served, the calculated refrigerant concentration limit (RCL) compliance, and the mitigation provisions

−

−```datasheet

−label: Action Submittals Required

−type: checkbox

−options:

− - "ACR copper tube product data (ASTM B280, temper, type, sizes)"

− - "Fitting and joint product data (braze and mechanical)"

− - "Brazing filler metal product data (AWS A5.8)"

− - "Refrigerant line insulation product data (ASTM C534)"

− - "Field refrigerant specialty product data (driers, valves, sight glass)"

− - "Refrigerant detection system / interlock product data (A2L)"

− - "Refrigerant piping coordination drawings"

− - "Manufacturer line-sizing and length/lift verification"

− - "Brazing procedure and brazer qualification records"

− - "Pressure-test, evacuation, and charging plan"

− - "A2L refrigerant safety / RCL compliance plan"

−default: "ACR copper tube product data (ASTM B280, temper, type, sizes)"

−```

−

−## Closeout Submittals {toc}

−

−### At substantial completion, the Contractor shall provide the following before the refrigerant systems are accepted.

−

−- Signed and dated pressure-test reports for each circuit, recording the test medium (dry nitrogen, or nitrogen with trace refrigerant for leak location), the hold pressure on the high and low sides, the hold duration, the temperature-corrected pressure observations, and the pass/fail determination

−- Signed and dated evacuation reports recording the final vacuum achieved (in microns), the micron-rise (decay) test result after isolation from the vacuum pump, and the time held

−- Charging records documenting the refrigerant type, the total charge weighed into the system (factory charge plus field-added charge for line length), and the basis for the line-length charge adjustment per the manufacturer's instructions

−- As-built piping drawings reflecting actual routing, line sizes, equivalent lengths, oil-trap locations, and the location of each field-installed specialty

−- Operation and maintenance data for field-installed specialties and for the refrigerant detection system, including sensor calibration interval and end-of-life replacement date

−- A completed A2L mitigation commissioning record (where applicable) demonstrating that detection, alarm, and ventilation/shutoff interlock function as designed

−

−```datasheet

−label: Required Closeout Submittals

−type: checkbox

−options:

− - Signed and dated pressure-test reports for each circuit

− - Signed and dated evacuation reports (final vacuum and decay test)

− - Charging records (refrigerant type, total weighed charge, line-length basis)

− - As-built piping drawings

− - Operation and maintenance data for specialties and detection system

− - A2L mitigation commissioning record (where applicable)

−default:

− - "Signed and dated pressure-test reports for each circuit"

− - "Signed and dated evacuation reports (final vacuum and decay test)"

− - "Charging records (refrigerant type, total weighed charge, line-length basis)"

− - "As-built piping drawings"

− - "Operation and maintenance data for specialties and detection system"

− - "A2L mitigation commissioning record (where applicable)"

−```

−

−# Quality Assurance {toc}

−

−## Code Compliance {toc}

−

−### All refrigerant piping shall comply with ASME B31.5 for design pressure, materials, joints, fabrication, examination, and testing, and with ASHRAE 15 (or ASHRAE 15.2 for residential and light-commercial applications) for system safety, refrigerant quantity limits, and piping in or through occupied spaces.

−

−### The Contractor shall maintain a copy of ASME B31.5 and the applicable ASHRAE safety standard at the project site throughout installation.

−

−## Brazer Qualifications {toc}

−

−### Personnel performing brazed refrigerant joints shall be qualified under ASME Section IX for the brazing procedure, position, and tube configuration being brazed, and qualification records shall be available at the site.

−

−### The Contractor shall not allow unqualified personnel to make production joints; rework of joints made by unqualified personnel is at the Contractor's expense.

−

−### Where a brazer has not performed qualified brazing within six months, requalification shall be required before production work.

−

−## Examination of Brazed Joints {toc}

−

−### Each completed brazed joint shall be visually examined before it is insulated or otherwise made inaccessible.

−

−### A satisfactory joint shows a continuous, uniform fillet of filler metal completely around the circumference of the socket, with the filler metal visibly wetted to both members. {note}

−

−### Joints showing incomplete fill, voids, blowholes, or evidence of overheating (firescale, eroded base metal) shall be cut out and re-made.

−

−### Visual examination does not replace the pressure test; both are required.

−

−## Installer Qualifications {toc}

−

−### The Contractor performing refrigerant piping work shall hold a current EPA Section 608 certification for refrigerant handling and shall have documented experience installing field-piped refrigerant systems of comparable type and scope.

−

−### Personnel handling A2L refrigerants shall additionally have completed training on the safe handling, leak mitigation, and tool requirements specific to mildly flammable refrigerants.

−

−# Environmental and Service Conditions {toc}

−

−## Refrigerant and Safety Classification {toc}

−

−### The refrigerant type is determined by the equipment selected and shall be as scheduled.

−### The refrigerant safety classification (ASHRAE 34) governs the safety provisions required under ASHRAE 15 and 15.2 — most significantly whether the refrigerant is A1 (lower toxicity, nonflammable, e.g., R-410A) or A2L (lower toxicity, mildly flammable, e.g., R-32, R-454B). {note}

−

−### The refrigerant safety classification per ASHRAE 34 shall be specified, and the safety provisions of ASHRAE 15 and 15.2 applicable to that classification shall be applied.

−

−```datasheet

−label: Refrigerant Safety Classification (ASHRAE 34)

−type: radio

−options:

− - "A2L — mildly flammable (R-32, R-454B); ASHRAE 15/15.2 A2L provisions apply"

− - "A1 — nonflammable (R-410A); standard provisions apply"

−default: "A2L — mildly flammable (R-32, R-454B); ASHRAE 15/15.2 A2L provisions apply"

−```

−

−```datasheet

−label: Refrigerant

−type: select

−options:

− - "R-454B (A2L) — low-GWP, common in new split and packaged equipment"

− - "R-32 (A2L) — low-GWP, common in VRF and ductless equipment"

− - "R-410A (A1) — legacy nonflammable, existing-system service and replacement only"

−default: "R-454B (A2L) — low-GWP, common in new split and packaged equipment"

−```

−

−### Under the EPA AIM Act Technology Transition Rule, most new comfort-cooling equipment manufactured in or after 2025 uses an A2L refrigerant with a global-warming potential below the regulated limit, so A2L provisions apply to the majority of new systems. {note}

−

−## Design Pressures {toc}

−

−```datasheet

−label: High-Side Design Pressure

−type: range

−unit: psig

−drawing_ref: true

−options:

− min: 400

− max: 700

− setpoints: [400, 450, 500, 550, 600, 650, 700]

−default: 550

−```

−

−### Refrigerant piping shall be designed for the system design pressures established by ASME B31.5 for the refrigerant and the highest temperature the piping will experience on each side.

−

−### The high-side and low-side design pressures shall be not less than the equipment manufacturer's stamped maximum allowable pressures.

−

−### ACR copper tube of the selected type and wall is rated well above these pressures; the design-pressure requirement governs the selection of fittings, valves, and any field-installed specialties, which shall each be rated for the high-side design pressure unless they are isolated to the low side.

−

−# ACR Copper Tube {toc}

−

−```datasheet

−label: Copper Tube Standard

−type: radio

−options:

− - "ASTM B280 ACR copper tube — cleaned, dehydrated, nitrogen-charged, capped (standard)"

− - "ASTM B280 ACR copper tube, oxygen/medical-clean (where specified for critical systems)"

−default: "ASTM B280 ACR copper tube — cleaned, dehydrated, nitrogen-charged, capped (standard)"

−```

−

−```datasheet

−label: Copper Tube Temper and Form

−type: radio

−options:

− - "Hard-drawn straight lengths for runs larger than 7/8 in. OD and all exposed/rigid routing; annealed (soft) coil line set for sizes through 7/8 in. OD where bending is required"

− - "Hard-drawn straight lengths throughout (all sizes), with elbows and offsets made from fittings"

− - "Annealed (soft) coil line set throughout (small split systems, short runs)"

−default: "Hard-drawn straight lengths for runs larger than 7/8 in. OD and all exposed/rigid routing; annealed (soft) coil line set for sizes through 7/8 in. OD where bending is required"

−```

−

−## Refrigerant piping shall be seamless copper tube manufactured for air-conditioning and refrigeration field service in accordance with ASTM B280.

−

−## ACR tube is supplied internally cleaned, dehydrated, charged with a holding pressure of dry nitrogen, and capped at both ends to keep the bore clean and dry until the moment of installation. {note}

−

−## The Contractor shall keep tube capped and pressurized until immediately before brazing and shall cut, ream, and braze each length without leaving the bore open to ambient air any longer than necessary.

−

−## Plumbing-grade Type L tube to ASTM B88 is not interchangeable with ACR tube for this work because it is sized by nominal pipe size rather than actual outside diameter and is not supplied clean, dry, and capped; ACR tube to ASTM B280 (sized by actual OD) shall be used.

−

−## Hard-drawn (drawn-temper) tube is stiffer and stronger and holds a straight line with fewer supports, making it the standard for larger sizes, long mains, risers, and exposed routing; annealed (soft-temper) tube is supplied in coils and suits the short, flexible runs typical of small split systems and the final connections to indoor units. {note}

−

−## Annealed tube shall be bent with a forming tool or spring to avoid kinking; a kinked or flattened tube restricts flow and oil return and shall be cut out and replaced.

−

−## Soft tube shall not be used for long unsupported runs where it would sag and trap oil.

−

−# Joints and Fittings {toc}

−

−```datasheet

−label: Primary Joining Method

−type: radio

−options:

− - "Brazed throughout, with dry-nitrogen purge (standard)"

− - "Brazed mains; refrigerant-rated press/mechanical fittings where open flame is prohibited"

− - "Flare connections at equipment, brazed elsewhere"

−default: "Brazed throughout, with dry-nitrogen purge (standard)"

−```

−

−## Brazed joints shall use wrought copper braze-joint fittings conforming to ASME B16.50 (or solder-joint fittings to ASME B16.22 used in the braze configuration).

−

−## Where the system design and the refrigerant manufacturer's listing permit, refrigerant-rated mechanical or press fittings that are listed for the refrigerant (including A2L where applicable) and rated for the high-side design pressure may be used in lieu of brazing at locations where open-flame work is restricted.

−

−## Flare joints may be used only at equipment service connections that are designed for flare fittings and shall be made with a refrigeration flaring tool to the correct flare angle and torque.

−

−# Brazing Filler Metal {toc}

−

−```datasheet

−label: Brazing Filler Metal

−type: radio

−options:

− - "BCuP series (phosphorus-copper) for copper-to-copper joints, no flux (standard)"

− - "BAg series (silver alloy) with flux for copper-to-brass/bronze joints (service valves)"

−default: "BCuP series (phosphorus-copper) for copper-to-copper joints, no flux (standard)"

−```

−

−## Brazing filler metal shall conform to AWS A5.8.

−

−## For copper-to-copper joints, a phosphorus-bearing copper alloy of the BCuP series (typically BCuP-2 through BCuP-6, with a silver content as required for the joint clearance) shall be used; BCuP filler is self-fluxing on copper-to-copper joints and requires no flux.

−

−## For copper-to-brass or copper-to-bronze joints (such as at service valves), a silver alloy of the BAg series shall be used with the appropriate brazing flux.

−

−## Cadmium-bearing filler metals shall not be used.

−

−## Where flux is used, all flux residue shall be removed after brazing because it is corrosive.

−

−# Refrigerant Line Insulation {toc}

−

−```datasheet

−label: Insulation Material

−type: radio

−options:

− - "Closed-cell flexible elastomeric, ASTM C534 (standard)"

− - "Closed-cell elastomeric with factory-applied protective jacket (exposed/exterior)"

−default: "Closed-cell flexible elastomeric, ASTM C534 (standard)"

−```

−

−```datasheet

−label: Suction Line Insulation Wall Thickness

−type: select

−unit: in.

−options:

− - "1/2 in. — conditioned interior, short runs"

− - "3/4 in. — standard interior, most commercial applications"

− - "1 in. — long runs, high-humidity spaces, or where required by energy code"

−default: "3/4 in. — standard interior, most commercial applications"

−```

−

−```datasheet

−label: Liquid Line Insulation

−type: radio

−options:

− - "Insulate suction line only; liquid line uninsulated (standard)"

− - "Insulate both suction and liquid lines (heat-pump, long runs, or exposed liquid line)"

−default: "Insulate suction line only; liquid line uninsulated (standard)"

−```

−

−## Suction (and where present, any cold) refrigerant lines shall be insulated with preformed flexible elastomeric cellular (closed-cell) insulation conforming to ASTM C534.

−

−## Closed-cell elastomeric insulation is used because it is itself a continuous vapor retarder: a refrigerant suction line runs well below the ambient dew point, and an open-cell or breached insulation will sweat, drip, and corrode. {note}

−

−## The insulation shall have a flame-spread index of 25 or less and a smoke-developed index of 50 or less per ASTM E84 for installation in plenums and concealed spaces, or shall be otherwise listed for the location.

−

−## The suction line is always insulated to prevent condensation and to limit the heat gain that reduces capacity. {note}

−

−## The liquid line is normally left uninsulated because subcooling loss is small, but on heat-pump systems the "liquid" line carries warm vapor in heating mode and shall be insulated, and any liquid line exposed to high ambient or routed where its surface could sweat (or where it is subject to mechanical damage) shall be insulated.

−

−## Insulation seams and butt joints shall be adhered with the manufacturer's contact adhesive to maintain the vapor seal.

−

−## Insulation shall not be stretched at fittings, as stretched elastomeric insulation thins and eventually pulls apart, breaking the vapor seal.

−

−# Pipe Sizing and Routing {toc}

−

−## Line Sizing {toc}

−

−```datasheet

−label: Line Sizing Basis

−type: radio

−drawing_ref: "refrigerant piping drawings"

−options:

− - "Per equipment manufacturer's line-size tables for actual equivalent length and lift (standard)"

−default: "Per equipment manufacturer's line-size tables for actual equivalent length and lift (standard)"

−```

−

−### Refrigerant line sizes shall be [[drawing: as indicated on the refrigerant piping drawings]] and shall conform to the equipment manufacturer's published line-size tables for the actual equivalent length and the lift between units.

−

−### The Contractor shall not substitute line sizes.

−

−### Both undersizing and oversizing cause problems: an undersized line raises pressure drop, lowers capacity, and increases compressor work; an oversized suction or discharge line reduces vapor velocity below what is needed to carry oil up vertical risers, so oil collects in the system and starves the compressor. {note}

−

−### Suction and discharge risers in particular shall be sized to maintain the minimum oil-entrainment velocity at the system's minimum-capacity (part-load) operating condition.

−

−## Maximum Length and Lift {toc}

−

−```datasheet

−label: Maximum Total Refrigerant Pipe Length

−type: range

−unit: ft

−drawing_ref: true

−options:

− min: 50

− max: 3300

− setpoints: [50, 100, 165, 300, 500, 1000, 1640, 3300]

−default: 165

−```

−

−```datasheet

−label: Maximum Vertical Separation (Lift) Between Outdoor and Indoor Units

−type: range

−unit: ft

−drawing_ref: true

−options:

− min: 25

− max: 360

− setpoints: [25, 50, 90, 130, 165, 230, 360]

−default: 90

−```

−

−### Total piping length, equivalent length, and the maximum vertical separation (lift) between the outdoor unit and the farthest or highest indoor unit, and between indoor units, shall not exceed the equipment manufacturer's published limits for the system and refrigerant.

−

−### These limits are absolute; exceeding them voids the equipment warranty and causes loss of capacity, poor oil return, and migration problems. {note}

−

−### Where the layout cannot meet the limits, the Contractor shall notify the Engineer before installation rather than installing piping that exceeds them.

−

−## Oil Return and Traps {toc}

−

−```datasheet

−label: Oil-Return Provisions

−type: checkbox

−options:

− - "Trap at base of each suction/discharge riser"

− - "Intermediate traps on tall risers per manufacturer interval"

− - "Inverted trap at top of riser to prevent drain-back"

− - "Horizontal suction lines pitched toward compressor"

− - "Double riser where required for part-load oil entrainment"

−default: "Trap at base of each suction/discharge riser"

−```

−

−### The piping shall be routed and trapped so that compressor lubricating oil returns reliably to the compressor under all operating conditions.

−

−### On suction and discharge risers, oil P-traps (inverted traps at the top and a trap at the base of long risers) shall be provided where required by the equipment manufacturer's piping guidelines, typically at the base of each riser and at intervals up tall risers, to collect and lift oil in slugs at low load.

−

−### Horizontal suction lines shall be pitched downward in the direction of flow toward the compressor to assist oil return.

−

−### Double risers shall be provided where the manufacturer requires them to maintain oil-carrying velocity across a wide capacity-modulation range.

−

−## Routing and Branch Connections {toc}

−

−### Branch connections, headers, and refnet/joint fittings on VRF systems shall be the equipment manufacturer's specified branch components and shall be installed in the orientation the manufacturer requires (typically horizontal or with the branches in the same horizontal plane) so that refrigerant and oil distribute correctly.

−

−### Branch fittings shall not be installed in a vertical orientation unless the manufacturer expressly permits it.

−

−### A minimum straight-pipe length shall be maintained before and after each branch as the manufacturer requires.

−

−# Refrigerant Safety (A2L, RCL, ASHRAE 15) {toc}

−

−## Refrigerant Quantity and Concentration Limits {toc}

−

−```datasheet

−label: Refrigerant Concentration Compliance Basis

−type: radio

−options:

− - "Charge limited so full release stays below RCL / 25% LFL in smallest occupied space (no mitigation)"

− - "Charge exceeds limit — refrigerant detection system with mitigation provided per ASHRAE 15.2"

−default: "Charge limited so full release stays below RCL / 25% LFL in smallest occupied space (no mitigation)"

−```

−

−### Where refrigerant piping passes through or serves an occupied space, the system refrigerant charge shall be limited so that, in the event of a full release into the smallest occupied space served by the system, the resulting concentration does not exceed the refrigerant concentration limit (RCL) for an A1 refrigerant, and for an A2L refrigerant does not exceed 25% of the lower flammability limit (LFL), in accordance with ASHRAE 15 and ASHRAE 15.2.

−

−### The Contractor shall confirm that the as-installed charge (factory charge plus the line-length charge addition for the field piping) is within these limits for the smallest space served.

−

−### Where the charge would exceed the limit, mitigation (a refrigerant detection system with ventilation or circulation) is required, or the system shall be reconfigured.

−

−## Refrigerant Detection and Mitigation (A2L) {toc}

−

−```datasheet

−label: A2L Mitigation Provisions (where required)

−type: checkbox

−options:

− - "Refrigerant detection sensor(s) listed to UL 60335-2-40, located low in space"

− - "Alarm interlock to indoor unit / circulation fan"

− - "Dedicated mechanical ventilation interlock"

− - "Automatic line-set isolation (shutoff) valves to limit released charge"

− - "Audible/visual occupant alarm"

−default: "Refrigerant detection sensor(s) listed to UL 60335-2-40, located low in space"

−```

−

−### For A2L systems where the charge or the served space requires it, a refrigerant detection system (RDS) listed to UL 60335-2-40 shall be provided.

−

−### The detection sensor shall be located low in the space (A2L refrigerants are heavier than air and collect near the floor) at the location the equipment manufacturer specifies, and shall be set to alarm at a concentration below 25% of the LFL.

−

−### On alarm, the system shall initiate the mitigation action specified by the manufacturer — typically energizing the indoor unit fan or a dedicated ventilation fan to disperse the refrigerant, and/or closing line-set isolation valves to limit the released quantity.

−

−### Detection, alarm, and interlock wiring shall comply with NFPA 70.

−

−### Sensors have a finite service life and shall be installed with the manufacturer's end-of-life replacement date recorded in the closeout documents.

−

−## Piping in Occupied and Concealed Spaces {toc}

−

−### Refrigerant piping installed in or through occupied spaces, plenums, shafts, and concealed locations shall be installed and protected so that a release is detected and mitigated as required above, and so that the piping is protected from mechanical damage.

−

−### Joints in concealed and inaccessible spaces shall be minimized; where unavoidable, they shall be brazed (not mechanical or flare joints) to the maximum extent practicable, since brazed joints are the most leak-resistant.

−

−### Tools used on A2L systems (recovery machines, vacuum pumps, gauges) shall be rated for the flammable refrigerant.

−

−# Joining and Brazing {toc}

−

−## Dry-Nitrogen Purge During Brazing {toc}

−

−```datasheet

−label: Dry-Nitrogen Purge During Brazing

−type: radio

−options:

− - "Required on all brazed refrigerant joints, maintained until joint cools (standard)"

−default: "Required on all brazed refrigerant joints, maintained until joint cools (standard)"

−```

−

−### While any joint is being brazed, the interior of the tube shall be continuously purged with a low, positive flow of oil-free dry nitrogen, and the purge shall be maintained until the joint has cooled.

−

−### Without an inert purge, the copper interior oxidizes in the brazing heat and forms a black, flaky cupric/cuprous oxide scale (firescale) inside the tube, which later breaks loose in the refrigerant and oil stream and travels to the metering device and compressor, plugging the expansion valve or capillary, scoring the compressor, and contaminating the oil. {note}

−

−### Dry nitrogen shall be used as the purge gas — never oxygen, CO2, or shop air.

−

−## Brazing Procedure {toc}

−

−### Tube ends shall be cut square with a tube cutter, reamed to remove the inside burr, and cleaned.

−

−### The fitting and tube shall be assembled to the correct insertion depth.

−

−### The joint shall be heated uniformly to brazing temperature and the filler metal applied so that capillary action draws filler completely into and around the socket, producing a continuous fillet.

−

−### The tube shall not be overheated, because localized overheating erodes the base metal and burns the surrounding insulation.

−

−### Burrs, filings, and cut chips shall be kept out of the bore.

−

−### A flow of nitrogen shall be passing through the tube during the entire heating and cooling of each joint.

−

−# Insulation {toc}

−

−## Insulation shall be applied after the piping has passed the pressure test and the leak test, but the Contractor shall plan the work so that joints to be insulated remain accessible for the test.

−

−## Wherever practicable, elastomeric tube insulation shall be slipped over the tube before brazing the last joint (slid back during brazing, then returned and the seam sealed), rather than slit and re-sealed, because an unslit sleeve has no longitudinal seam to fail.

−

−## Where insulation must be slit to install it, the seam and all butt joints shall be adhered continuously with the manufacturer's adhesive to restore the vapor seal.

−

−## Penetrations and Terminations {toc}

−

−### Insulation shall be continuous through sleeves and penetrations and shall be protected where it passes through walls and floors.

−

−### At terminations and at exposed exterior locations, the insulation shall be protected with a UV-resistant jacket or coating, because elastomeric insulation degrades under sunlight.

−

−### Insulation shall not be compressed at pipe supports; insulation protection shields or inserts shall be used so the support load does not crush the insulation and create a condensation point.

−

−# Penetrations, Firestopping, and Support {toc}

−

−## Sleeves {toc}

−

−### Refrigerant piping passing through walls, floors, and roofs shall be installed in sleeves sized to pass the insulated tube without compressing the insulation.

−

−### Sleeves through fire-rated and floor assemblies shall extend as required by code, and the annular space shall be sealed.

−

−## Firestopping {toc}

−

−### Penetrations of fire-rated walls, floors, and ceilings by refrigerant piping shall be sealed with a firestop system tested and listed for the penetrant (insulated copper tube) and the rating of the assembly, in accordance with [[sync/firestopping]].

−

−### The firestop system shall accommodate the combustible elastomeric insulation, which typically requires an intumescent device or wrap sized for the insulated tube.

−

−## Supports {toc}

−

−```datasheet

−label: Maximum Support Spacing — Hard-Drawn Copper Tube

−type: select

−unit: ft (by tube OD)

−drawing_ref: true

−options:

− - "Up to 5/8 in. OD — 6 ft; 3/4 in. to 1-1/8 in. OD — 8 ft; 1-3/8 in. OD and larger — 10 ft"

−default: "Up to 5/8 in. OD — 6 ft; 3/4 in. to 1-1/8 in. OD — 8 ft; 1-3/8 in. OD and larger — 10 ft"

−```

−

−### Piping shall be supported in accordance with MSS SP-58 at intervals appropriate to the tube size and temper, with closer spacing for soft-temper tube, and at every change of direction and at each piece of in-line specialty.

−

−### Supports on insulated lines shall bear on a protection shield or insert so the insulation and its vapor seal are not crushed.

−

−### Tube shall be isolated from dissimilar metal supports to prevent galvanic action and from sources of vibration; the connection to vibrating equipment shall include the manufacturer's vibration provisions so that vibration is not transmitted into brazed joints.

−

−# Pressure Testing, Evacuation, and Charging {toc}

−

−## Pressure and Leak Test {toc}

−

−```datasheet

−label: Pressure Test Medium

−type: radio

−options:

− - "Oil-free dry nitrogen (standard)"

− - "Dry nitrogen with trace refrigerant for electronic leak detection"

−default: "Oil-free dry nitrogen (standard)"

−```

−

−```datasheet

−label: Pressure Test Hold Duration

−type: range

−unit: hours

−options:

− min: 1

− max: 24

− setpoints: [1, 2, 4, 8, 12, 24]

−default: 4

−```

−

−### After brazing is complete and before evacuation, the system field piping shall be pressure-tested with oil-free dry nitrogen (a small trace of refrigerant may be added to permit electronic leak detection, but the test medium shall be predominantly nitrogen); the system shall never be pressure-tested or "blown out" with oxygen or air.

−

−### The high side and low side shall be tested to the test pressure required by ASME B31.5 and the equipment manufacturer, but not exceeding the lowest-rated component in the circuit.

−

−### The pressure shall be held for the specified duration, and the observed pressure shall be corrected for ambient temperature change before judging the result, because a 1°F change in nitrogen temperature shifts the gauge reading independently of any leak.

−

−### A pressure drop not attributable to temperature indicates a leak, which shall be located and repaired and the joint re-tested.

−

−## Evacuation {toc}

−

−```datasheet

−label: Evacuation Target (Final Absolute Pressure)

−type: range

−unit: microns

−options:

− min: 250

− max: 1000

− setpoints: [250, 300, 500, 750, 1000]

−default: 500

−```

−

−```datasheet

−label: Evacuation Method

−type: radio

−options:

− - "Triple evacuation with dry-nitrogen sweep between pulldowns (standard)"

− - "Single deep evacuation to target with extended hold"

−default: "Triple evacuation with dry-nitrogen sweep between pulldowns (standard)"

−```

−

−### After the system passes the pressure test, the nitrogen shall be recovered and the system evacuated with a vacuum pump to remove all air, non-condensable gas, and moisture.

−

−### Evacuation shall be performed through both the high-side and low-side service ports using large-bore hoses or a core-removal tool so the pump can pull the system down efficiently.

−

−### The system shall be evacuated to a final absolute pressure of 500 microns or lower.

−

−### A triple (deep) evacuation shall be performed: evacuate, break the vacuum with dry nitrogen, evacuate again, break again, and evacuate a third time to the final 500-micron target.

−

−### Breaking the vacuum with dry nitrogen between pulldowns dilutes and sweeps out residual moisture far more effectively than a single long pulldown, because water vaporizes slowly at low absolute pressure. {note}

−

−## Decay (Standing Vacuum) Test {toc}

−

−```datasheet

−label: Standing-Vacuum Decay Acceptance

−type: radio

−options:

− - "Hold isolated for 15 minutes; rise to no more than 500 microns and stabilizing (standard)"

− - "Hold isolated for 30 minutes; rise to no more than 500 microns and stabilizing"

−default: "Hold isolated for 15 minutes; rise to no more than 500 microns and stabilizing (standard)"

−```

−

−### After reaching the 500-micron target, the system shall be isolated from the vacuum pump (valve off the pump, leaving the micron gauge reading the system) and held.

−

−### A system that is dry and leak-free will hold a steady vacuum or rise only slightly and stabilize; a rise that continues without stabilizing indicates a leak, and a rise that stabilizes at a higher value indicates remaining moisture (off-gassing). {note}

−

−### The system shall pass a decay test before refrigerant is charged.

−

−## Charging {toc}

−

−```datasheet

−label: Charging Method

−type: radio

−options:

− - "Weighed charge: factory charge plus calculated line-length addition (standard)"

− - "Weighed-in base charge, final trim per manufacturer subcooling/superheat target"

−default: "Weighed charge: factory charge plus calculated line-length addition (standard)"

−```

−

−### Only the refrigerant specified for the equipment shall be charged; refrigerants shall not be mixed or topped off with a different refrigerant.

−

−### Blended (zeotropic) refrigerants such as R-454B shall be charged from the cylinder as liquid (cylinder inverted or with a dip tube) to preserve the blend composition, then metered into the system per the equipment instructions.

−

−### The total charge shall equal the factory charge plus the line-length charge addition calculated from the liquid-line size and length per the manufacturer's table, weighed in with a charging scale and recorded.

−

−### The Contractor shall not charge by pressure or by sight glass alone where the manufacturer specifies a weighed charge.

−

−# Installation {toc}

−

−## The Contractor shall install all refrigerant piping in accordance with this standard, the contract drawings, ASME B31.5, the applicable ASHRAE safety standard, and the equipment manufacturer's installation instructions.

−

−## Where these conflict, the more stringent governs.

−

−## Tube shall be kept capped and under positive nitrogen pressure until the moment of brazing, and open tube ends shall be re-capped whenever work stops.

−

−## Cleanliness {toc}

−

−### The interior of the piping shall be kept clean, dry, and free of oxide, moisture, flux, and debris throughout installation.

−

−### The combination of capped ACR tube, the dry-nitrogen braze purge, the pressure test, and the triple evacuation is the means by which interior cleanliness is achieved and verified; none of these steps may be skipped.

−

−### A filter-drier shall be installed in the liquid line where the equipment manufacturer requires one, and its location shall remain accessible for future replacement.

−

−## Coordination {toc}

−

−### Routing, sizes, lengths, lifts, oil-trap and branch locations, and penetration locations shall be coordinated with the structural, architectural, and other trades on the coordination drawings before rough-in, and with the equipment standards [[sync/variable-refrigerant-flow-systems]] and [[sync/split-system-air-conditioners]].

−

−### Insulation thicknesses and the firestop systems shall be coordinated with [[sync/building-thermal-insulation]] and [[sync/firestopping]].

−

−### Routing shall be coordinated against [[drawing: the reflected ceiling plan and mechanical coordination drawings]].

−

−# Warranty {toc}

−

−## Warranty Period and Remedies {toc}

−

−### The Contractor shall warrant the refrigerant piping installation against leaks and defects in materials and workmanship for a period of not less than one year from substantial completion, or for the period stated in the contract documents if longer.

−

−### Any leak attributable to a field joint, and any compressor or metering-device failure attributable to interior contamination, inadequate evacuation, or moisture in the field piping, shall be corrected at the Contractor's expense, including the cost of recovering and recharging refrigerant and of replacing any contaminated refrigerant or oil.

−

−### The installation shall not void the equipment manufacturer's warranty, and the Contractor shall observe all manufacturer requirements (line sizing, length and lift limits, evacuation, and charge) on which that warranty depends.

+---

+title: Refrigerant Piping

+category: Mechanical / Piping & Pumps

+description: >

+ When to use: Field-installed refrigerant piping that interconnects the components of split-system air conditioners and heat pumps, variable refrigerant flow systems, direct-expansion coils, computer room units, and packaged equipment supplied with a field-piped condensing section. Covers tube material and temper, joining methods and brazing filler metal, braze purge, field-installed specialties, line routing, oil return, insulation and its vapor seal, supports and seismic restraint, penetrations and firestopping, refrigerant concentration limits and the detection and mitigation provisions that go with mildly flammable refrigerants, piping identification, and the pressure test, evacuation, decay test, and charging sequence that puts the system into service.

+ Not intended for: The air conditioning and heat pump equipment itself and its factory charge and factory piping ([[sync/variable-refrigerant-flow-systems]], [[sync/split-system-air-conditioners]], [[sync/computer-room-air-conditioning]]); chilled water, condenser water, and heating water piping ([[sync/chilled-and-condenser-water-piping]]); condensate drainage from indoor units and coils; power and control wiring between units; refrigerating machinery rooms and the ventilation, detection, and pressure relief serving them; ammonia refrigeration systems governed by IIAR standards; carbon dioxide transcritical refrigeration racks; and any system whose design temperature falls below the ASME B31.5 scope.

+---

+# Scope {toc}

+## This standard governs the tube, fittings, joints, specialties, insulation, supports, and field procedures that make up refrigerant piping installed in the field between the components of a refrigeration or air conditioning system. {note}

+## The scope begins at the service valve or stub connection on the outdoor, condensing, or heat recovery unit and ends at the service valve or stub connection at each indoor unit, fan coil, or direct-expansion coil, and it includes every branch fitting, header, and specialty in between. {note}

+## Refrigerant piping is a sealed high-pressure circuit that carries a two-phase fluid together with the compressor lubricating oil that has to travel the whole loop and come back; the bore of the tube is therefore a working surface, and any moisture, oxide scale, particulate, or non-condensable gas sealed inside it stays in the system for the life of the equipment. {note}

+## Because the interior condition of the tube cannot be inspected after the system is closed, the procedures in this standard that establish that condition carry the same weight as the materials, and a system that was brazed without an inert purge or charged without a verified evacuation is a defective installation even where every joint holds pressure. {note}

+## The following are governed elsewhere and are outside this standard: {note}

+- the air conditioning, heat pump, and refrigeration equipment itself, its factory charge, and the piping inside its casing

+- chilled water, condenser water, heating water, and steam piping

+- condensate drainage from indoor units, coils, and drain pans

+- power wiring, control wiring, and communication cabling between units

+- refrigerating machinery rooms and the ventilation, detection, alarm, and pressure relief provisions that serve the room rather than the piping

+- ammonia and carbon dioxide industrial refrigeration systems

+- the structural attachment points to which piping supports are fastened

+## Refrigerant piping shall be routed as indicated on [[drawing: the mechanical plans]].

+## All work under this standard shall comply with ASME B31.5, with ASHRAE 15 or ASHRAE 15.2 as applicable to the system, and with the adopted mechanical code.

+## The equipment manufacturer's published piping requirements shall be treated as mandatory requirements of this standard, and the Contractor shall not exceed a published length, elevation, or line size limit even where this standard or the drawings would otherwise permit it.

+## The equipment warranty is conditioned on the piping being installed within the published limits, so a piping decision that departs from them transfers the cost of any resulting equipment failure to the party that made the departure. {note}

+# Referenced Standards {toc}

+## Materials, fabrication, and installation shall comply with the latest adopted edition of each of the following unless a specific edition is cited.

+## Where the contract documents, the Authority Having Jurisdiction, or two referenced standards impose conflicting requirements, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.

+| Standard | Title |

+|----------|-------|

+| ASME B31.5 | Refrigeration Piping and Heat Transfer Components |

+| ASME BPVC Section IX | Welding, Brazing, and Fusing Qualifications |

+| ASME B16.18 | Cast Copper Alloy Solder Joint Pressure Fittings |

+| ASME B16.22 | Wrought Copper and Copper Alloy Solder Joint Pressure Fittings |

+| ASME B16.50 | Wrought Copper and Copper Alloy Braze Joint Pressure Fittings |

+| ASHRAE 15 | Safety Standard for Refrigeration Systems |

+| ASHRAE 15.2 | Safety Standard for Refrigeration Systems in Residential and Light Commercial Applications |

+| ASHRAE 34 | Designation and Safety Classification of Refrigerants |

+| ASTM B88 | Seamless Copper Water Tube |

+| ASTM A240 | Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications |

+| ASTM B209 | Aluminum and Aluminum-Alloy Sheet and Plate |

+| ASTM B280 | Seamless Copper Tube for Air Conditioning and Refrigeration Field Service |

+| ASTM B819 | Seamless Copper Tube for Medical Gas Systems |

+| ASTM C534 | Preformed Flexible Elastomeric Cellular Thermal Insulation in Sheet and Tubular Form |

+| ASTM C547 | Mineral Fiber Pipe Insulation |

+| ASTM C552 | Cellular Glass Thermal Insulation |

+| ASTM C591 | Unfaced Preformed Rigid Cellular Polyisocyanurate Thermal Insulation |

+| ASTM C1126 | Faced or Unfaced Rigid Cellular Phenolic Thermal Insulation |

+| ASTM C1136 | Flexible, Low Permeance Vapor Retarders for Thermal Insulation |

+| ASTM C1427 | Extruded Preformed Flexible Cellular Polyolefin Thermal Insulation in Sheet and Tubular Form |

+| ASTM E84 | Surface Burning Characteristics of Building Materials |

+| ASTM E814 | Fire Tests of Penetration Firestop Systems |

+| AWS A5.8 | Filler Metals for Brazing and Braze Welding |

+| ASCE 7 | Minimum Design Loads and Associated Criteria for Buildings and Other Structures |

+| MSS SP-58 | Pipe Hangers and Supports: Materials, Design, Manufacture, Selection, Application, and Installation |

+| NFPA 70 | National Electrical Code |

+| UL 60335-2-40 | Electrical Heat Pumps, Air-Conditioners, and Dehumidifiers |

+| IMC | International Mechanical Code |

+| UMC | Uniform Mechanical Code |

+| 40 CFR Part 82 Subpart F | Recycling and Emissions Reduction |

+| 40 CFR Part 84 | Phasedown of Hydrofluorocarbons, Technology Transition |

+# Submittals {toc}

+## Action Submittals {toc}

+### The Contractor shall submit the following for review before refrigerant piping materials are procured:

+- product data for the tube, giving the product standard, temper, outside diameter and wall thickness for each line size, and the packaging condition in which the tube is delivered

+- product data for every fitting and joint type proposed, giving the product standard or listing, the pressure rating, and the refrigerants the joint is listed for

+- product data for the brazing filler metal, giving the AWS A5.8 classification, the nominal composition, the brazing temperature range, and whether flux is required

+- product data for the refrigerant line insulation, giving the product standard, thermal conductivity, water vapor permeance, service temperature range, and the ASTM E84 flame spread and smoke developed indices

+- product data for the insulation jacket, coating, or protective covering proposed for exposed and exterior locations

+- product data for each field-installed specialty, giving the pressure rating, connection type, refrigerant compatibility, and the service access the item requires

+- product data for the refrigerant detection sensors and the mitigation interlock devices, giving the listing, the detectable refrigerants, the alarm set point range, and the published sensor service life

+- product data for pipe supports, hangers, shields, and inserts, identifying the MSS SP-58 component type and finish for each

+- the firestop system listing for each penetration condition, identifying the tested assembly by its listing designation

+- a refrigerant piping layout showing routing, line sizes, equivalent lengths, elevation changes, branch and header locations, specialty locations, support locations, and penetration locations

+- the piping design output from the equipment manufacturer's selection method, demonstrating that the proposed line sizes, equivalent lengths, and elevation differences fall within the published limits for the selected system and refrigerant

+```datasheet

+label: Action Submittal Package

+type: checkbox

+options:

+ - "Tube product data"

+ - "Fitting and joint product data"

+ - "Brazing filler metal product data"

+ - "Insulation product data"

+ - "Insulation jacket and coating product data"

+ - "Field-installed specialty product data"

+ - "Refrigerant detection and mitigation product data"

+ - "Pipe support and hanger product data"

+ - "Firestop system listings"

+ - "Refrigerant piping layout"

+ - "Piping design output from the equipment selection method"

+```

+### Refrigerant piping shall not be fabricated or installed until the corresponding action submittals have been reviewed and returned.

+## Informational Submittals {toc}

+### The Contractor shall submit the following qualifications, calculations, and plans with or before the action submittals:

+- the brazing procedure specification and the supporting procedure qualification record for each joint configuration to be brazed

+- the brazer performance qualification record for every individual who will make a production joint, with the date of the qualifying test and the date of the most recent qualified brazing performed

+- refrigerant handling certification under 40 CFR Part 82 Subpart F for every individual who will open, evacuate, charge, or recover a refrigerant circuit

+- evidence of training in mildly flammable refrigerant handling for every individual who will work on a system carrying a refrigerant classified in a flammable safety group

+- the refrigerant concentration calculation for each system, identifying the total system charge, the smallest occupied space the system serves, the volume used for that space, and the limit the calculation is checked against

+- the mitigation design for each system whose charge exceeds the limit without mitigation, identifying the sensor locations, the alarm set point, the mitigation action, and the airflow or shutoff provision that carries it out

+- the pressure test, evacuation, and charging plan, identifying the test medium, test pressures, hold duration, leak location method, vacuum target, decay acceptance criterion, charging method, and the point in the construction sequence at which each step occurs

+- seismic restraint calculations or the pre-approved restraint detail the Contractor intends to use, with the listing or approval identified

+```datasheet

+label: Informational Submittal Package

+type: checkbox

+options:

+ - "Brazing procedure specification and qualification record"

+ - "Brazer performance qualification records"

+ - "Refrigerant handling certifications"

+ - "Flammable refrigerant training records"

+ - "Refrigerant concentration calculation"

+ - "Mitigation design"

+ - "Pressure test, evacuation, and charging plan"

+ - "Seismic restraint calculations or pre-approved detail"

+```

+## Closeout Submittals {toc}

+### The Contractor shall submit the following before the refrigerant systems are accepted:

+- a signed and dated pressure test report for each circuit, recording the test medium, the high side and low side test pressures, the hold duration, the ambient temperature and gauge pressure at the start and at the end of the hold, the temperature-corrected result, and the acceptance determination

+- a signed and dated evacuation report for each circuit, recording the vacuum target, the final absolute pressure reached, the number of pulldowns, the decay hold duration, the pressure at the end of the hold, and the acceptance determination

+- a charging record for each circuit, recording the refrigerant designation, the cylinder lot identification, the base charge, the calculated line-length addition and the liquid line size and length it was computed from, and the total weight charged

+- an as-built refrigerant piping layout recording the installed routing, line sizes, equivalent lengths, elevation changes, specialty locations, and penetration locations

+- operation and maintenance data for the field-installed specialties and for the refrigerant detection system, including the replacement interval and the calculated end-of-service date for each detection sensor

+- a commissioning record for the mitigation provisions, demonstrating that detection, alarm, and the mitigation action operated as designed on a simulated or introduced signal

+- warranty documentation for the piping installation and for each field-installed specialty

+- a signed receipt from the Owner for the spare parts delivered

+```datasheet

+label: Closeout Submittal Package

+type: checkbox

+options:

+ - "Signed pressure test reports"

+ - "Signed evacuation and decay test reports"

+ - "Charging records"

+ - "As-built refrigerant piping layout"

+ - "Operation and maintenance data"

+ - "Mitigation commissioning record"

+ - "Warranty documentation"

+ - "Spare parts receipt"

+```

+# Quality Assurance {toc}

+## Brazing Qualification {toc}

+### Brazing procedures shall be qualified in accordance with ASME BPVC Section IX for the base metals, filler metal, joint configuration, and position to be used in production.

+### Every individual who makes a production brazed joint shall hold a current brazer performance qualification for the procedure and position being used.

+### A brazer whose qualification has lapsed because no qualified brazing was performed within the preceding six months shall be requalified before making a production joint.

+### Qualification records for the procedure and for every brazer working on the project shall be kept at the site and made available on request.

+### Joints made by an individual whose qualification was not current at the time of brazing shall be cut out and remade, and the cost of the removal, the replacement material, the remade joint, and any repeated testing shall be borne by the Contractor.

+## Refrigerant Handling Certification {toc}

+### Refrigerant circuits shall be opened, evacuated, charged, and recovered only by an individual certified under 40 CFR Part 82 Subpart F.

+### Where the system carries a refrigerant classified in a flammable safety group under ASHRAE 34, the individuals working on it shall have completed training covering the handling, storage, leak response, and tool requirements that apply to that refrigerant.

+### Recovery machines, vacuum pumps, manifolds, leak detectors, and charging equipment used on a system carrying a refrigerant classified in a flammable safety group shall be rated by their makers for that service.

+## Visual Examination of Brazed Joints {toc}

+### Each completed brazed joint shall be visually examined before it is insulated, enclosed, or otherwise made inaccessible.

+### An acceptable joint shows a continuous fillet of filler metal around the full circumference of the socket with the filler visibly wetted to both members, and shows no firescale, no eroded base metal, and no melted or scorched adjacent insulation. {note}

+### A joint that does not meet the acceptance description in this article shall be cut out and remade.

+### Where the parties disagree whether a joint meets the acceptance description, the Engineer of Record shall make the initial determination.

+### Visual examination shall not be substituted for the pressure test, and both shall be performed on every circuit.

+# Refrigerant and Safety Classification {toc}

+## The refrigerant a system carries sets the design pressure the piping must hold, whether the charge is limited by an occupied-space concentration rule, whether detection and mitigation are required, and how the charge is metered into the system, so it is the first fact this standard needs. {note}

+## The refrigerant shall be as indicated in the datasheet.

+```datasheet

+label: Refrigerant Designation (ASHRAE 34)

+type: select

+drawing_ref: "the mechanical equipment schedule"

+options:

+ - "R-410A"

+ - "R-454B"

+ - "R-32"

+ - "R-466A"

+ - "R-407C"

+ - "R-448A"

+ - "R-449A"

+ - "R-513A"

+ - "R-134a"

+ - "R-1234ze(E)"

+ - "R-22"

+default: deferred

+```

+## The refrigerant safety group shall be as indicated in the datasheet.

+```datasheet

+label: Refrigerant Safety Group (ASHRAE 34)

+type: select

+derived: "the safety classification ASHRAE 34 publishes for the selected refrigerant designation"

+options:

+ - "A1"

+ - "A2L"

+ - "A2"

+ - "A3"

+ - "B1"

+ - "B2L"

+ - "B2"

+ - "B3"

+default: derived

+```

+## The safety group is the switch that turns the concentration limit, detection, and mitigation articles of this standard on or off, and it follows from the refrigerant rather than from any project decision. {note}

+## Under the technology transition rule at 40 CFR Part 84, comfort cooling equipment manufactured after the compliance date for its class is restricted to refrigerants below a stated global warming potential, and the refrigerants that meet that limit at the pressures this equipment runs at are largely classified A2L. {note}

+## Only the refrigerant the equipment is listed and charged for shall be introduced into the system.

+## Refrigerants shall not be mixed, and a system shall not be topped off with a refrigerant other than the one it was charged with.

+## Where an existing system is extended or altered under this standard, the Contractor shall confirm the refrigerant present in the existing circuit before any new material is connected to it.

+# Design Pressure {toc}

+## Piping, fittings, valves, and specialties shall be rated for the design pressures established under this article, and no component shall be installed in a circuit whose design pressure exceeds the component's own rating.

+## The high side design pressure shall be as indicated in the datasheet.

+```datasheet

+label: High-Side Design Pressure

+type: range

+unit: psig

+derived: "the saturation pressure of the selected refrigerant at the highest temperature the high side will reach, taken not lower than the maximum allowable pressure marked on the equipment"

+options:

+ min: 150

+ max: 800

+ setpoints: [150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800]

+default: derived

+```

+## The low side design pressure shall be as indicated in the datasheet.

+```datasheet

+label: Low-Side Design Pressure

+type: range

+unit: psig

+derived: "the saturation pressure of the selected refrigerant at the highest temperature the low side will reach while the system is idle, taken not lower than the maximum allowable pressure marked on the equipment"

+options:

+ min: 100

+ max: 600

+ setpoints: [100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600]

+default: derived

+```

+## The low side of a system that sits idle in a warm space equalizes toward the ambient saturation pressure rather than the operating suction pressure, which is why the low side design pressure is set from a standing condition and not from the running one. {note}

+## A component isolated on the low side by a valve that can be closed while the high side is pressurized shall be rated for the high side design pressure unless a pressure relief device protects it.

+# Tube {toc}

+## Tube Material and Product Standard {toc}

+### Refrigerant tube shall be as indicated in the datasheet.

+```datasheet

+label: Tube Material and Product Standard

+type: select

+options:

+ - "ASTM B280 copper tube for air conditioning and refrigeration field service"

+ - "ASTM B819 copper tube for medical gas systems"

+ - "ASTM B88 copper water tube"

+ - "Aluminum tube furnished as part of a listed line set assembly"

+default: "ASTM B280 copper tube for air conditioning and refrigeration field service"

+```

+### Tube furnished under ASTM B280 or ASTM B819 is sized by actual outside diameter, is cleaned and dehydrated in manufacture, and is delivered under a holding charge of dry nitrogen with both ends capped; tube furnished under ASTM B88 is sized by nominal water tube size and carries no equivalent cleanliness or packaging requirement. {note}

+### Where the datasheet selects ASTM B88 tube, the Contractor shall confirm that the adopted mechanical code permits water tube in refrigerant service for the selected refrigerant, and shall clean, dehydrate, and cap the tube to the condition described in this article before it is brought to the site.

+### Where the datasheet selects aluminum tube, it shall be furnished only as part of a line set assembly listed with the equipment for the selected refrigerant, and it shall be joined only by the method that listing covers.

+### Tube wall thickness shall be not less than the thickness ASME B31.5 requires at the high side design pressure for the outside diameter installed, and not less than the wall the selected product standard publishes for that outside diameter.

+### Tube shall not be selected in a size other than the size established for the line under this standard.

+## Temper and Form {toc}

+### Drawn temper tube is stiffer, holds a straight line between widely spaced supports, and is furnished in straight lengths; annealed temper tube is furnished in coils, can be bent without fittings, and needs closer support to keep from sagging into a low point that traps oil. {note}

+### The tempers permitted on the project shall be as indicated in the datasheet.

+```datasheet

+label: Permitted Tube Tempers

+type: checkbox

+options:

+ - "Drawn temper straight length"

+ - "Annealed temper coil"

+default:

+ - "Drawn temper straight length"

+ - "Annealed temper coil"

+```

+### The largest outside diameter that may be furnished in annealed temper shall be as indicated in the datasheet.

+```datasheet

+label: Largest Tube Outside Diameter Permitted in Annealed Temper

+type: range

+unit: in.

+options:

+ min: 0

+ max: 1.625

+ setpoints: [0, 0.375, 0.5, 0.625, 0.75, 0.875, 1.125, 1.375, 1.625]

+default: 0.875

+```

+### Setting this diameter to zero withholds annealed temper from the project entirely, which is the arrangement used where every run is to be made up from straight lengths and fittings. {note}

+### Annealed tube shall be bent with a bending tool or spring sized for the tube.

+### A tube that has been kinked, flattened, or reduced in bore at a bend shall be cut out and replaced rather than straightened.

+### Annealed tube shall not be used on a run whose support spacing would allow it to sag between supports.

+# Joints and Fittings {toc}

+## Permitted Joining Methods {toc}

+### The joining methods permitted on the project shall be as indicated in the datasheet.

+```datasheet

+label: Permitted Joining Methods

+type: checkbox

+options:

+ - "Brazed socket joint"

+ - "Refrigerant-rated press-connect joint"

+ - "Refrigerant-rated flare joint"

+ - "Refrigerant-rated bite-type mechanical joint"

+ - "Refrigerant-rated push-to-connect joint"

+default:

+ - "Brazed socket joint"

+ - "Refrigerant-rated flare joint"

+```

+### A brazed socket joint has no elastomeric seal and no mechanical preload to relax, which is why it remains the reference against which the other methods are judged; the mechanical and press methods trade some of that permanence for the ability to make a joint where an open flame is not allowed or where the work must be done without a hot work permit. {note}

+### Every joint shall be rated by its maker for the high side design pressure and listed for the refrigerant the system carries.

+### A joining method not selected in the datasheet shall not be used, and a joint made by an unselected method shall be removed and remade by a selected method at the Contractor's expense.

+### Flare joints shall be made only at a connection designed to receive a flare, using a flaring tool that produces the flare angle the connection requires, and shall be tightened to the published torque with a torque wrench.

+### Press-connect, bite-type, and push-to-connect joints shall be made with the tool, jaw, depth mark, and preparation the joint listing requires.

+## Joints in Concealed and Inaccessible Locations {toc}

+### A joint that cannot be reached is a joint that cannot be re-torqued, re-tested, or repaired without opening construction, and every joining method behaves differently under that condition. {note}

+### The joining methods permitted in concealed and inaccessible locations shall be as indicated in the datasheet.

+```datasheet

+label: Joining Methods Permitted in Concealed and Inaccessible Locations

+type: checkbox

+options:

+ - "Brazed socket joint"

+ - "Refrigerant-rated press-connect joint"

+ - "Refrigerant-rated flare joint"

+ - "Refrigerant-rated bite-type mechanical joint"

+ - "Refrigerant-rated push-to-connect joint"

+default:

+ - "Brazed socket joint"

+```

+### The number of joints located in concealed and inaccessible spaces shall be held to the number the routing requires.

+### A joint shall not be concealed until the circuit containing it has passed the pressure test required by this standard.

+## Fittings {toc}

+### The braze-joint fitting standards permitted on the project shall be as indicated in the datasheet.

+```datasheet

+label: Permitted Braze-Joint Fitting Standards

+type: checkbox

+options:

+ - "ASME B16.50 wrought copper braze-joint pressure fittings"

+ - "ASME B16.22 wrought copper solder-joint pressure fittings"

+ - "ASME B16.18 cast copper alloy solder-joint pressure fittings"

+default:

+ - "ASME B16.50 wrought copper braze-joint pressure fittings"

+ - "ASME B16.22 wrought copper solder-joint pressure fittings"

+```

+### Fittings shall be furnished clean, dry, and capped or bagged, and shall be kept that way until the moment of assembly.

+### Reducing bushings shall not be used where a reducing fitting of the required configuration is manufactured in the sizes being joined.

+### Branch connections shall be made with manufactured fittings, and a branch shall not be formed by drilling or extruding a hole in the run tube.

+## Brazing Filler Metal {toc}

+### The filler metal for copper-to-copper joints shall be as indicated in the datasheet.

+```datasheet

+label: Filler Metal Classification for Copper-to-Copper Joints

+type: select

+options:

+ - "AWS A5.8 BCuP-2"

+ - "AWS A5.8 BCuP-3"

+ - "AWS A5.8 BCuP-4"

+ - "AWS A5.8 BCuP-5"

+ - "AWS A5.8 BCuP-6"

+ - "AWS A5.8 BAg-5"

+ - "AWS A5.8 BAg-7"

+ - "AWS A5.8 BAg-24"

+```

+### The filler metal for joints between copper and a copper alloy shall be as indicated in the datasheet.

+```datasheet

+label: Filler Metal Classification for Copper-to-Brass and Copper-to-Bronze Joints

+type: select

+options:

+ - "AWS A5.8 BAg-5"

+ - "AWS A5.8 BAg-7"

+ - "AWS A5.8 BAg-24"

+ - "AWS A5.8 BAg-34"

+ - "AWS A5.8 BAg-36"

+```

+### Silver content buys flow and ductility: a low-silver phosphorus-copper filler is stiffer and needs a tighter joint clearance to fill by capillary action, while a higher-silver filler flows into a wider clearance and tolerates more vibration once cold. {note}

+### A phosphorus-bearing filler metal shall not be used on a joint in which either member is ferrous, because the phosphide layer that forms at such a joint is brittle.

+### Brazing flux shall not be applied to a joint between two copper members made with a phosphorus-bearing filler metal.

+### Brazing flux shall be applied to a joint in which either member is a copper alloy, and shall be applied to the tube surface rather than being packed into the socket.

+### Flux residue shall be removed from the outside of the completed joint before the joint is insulated, because the residue is corrosive to copper in the presence of moisture.

+### Cadmium-bearing brazing filler metal shall not be used on this project.

+# Field-Installed Refrigerant Specialties {toc}

+## Every device inserted into the refrigerant circuit is a potential leak path and a pressure drop, so the specialties installed in the field piping are a deliberate selection rather than a default inventory. {note}

+## The specialties installed in the field piping shall be as indicated in the datasheet.

+```datasheet

+label: Field-Installed Refrigerant Specialties

+type: checkbox

+options:

+ - "Liquid line filter-drier"

+ - "Suction line filter-drier"

+ - "Moisture-indicating sight glass"

+ - "Liquid line solenoid valve"

+ - "Access ports at each unit connection"

+ - "Line isolation ball valves"

+ - "Pressure relief device on isolatable sections"

+ - "Vibration absorber at each compressor connection"

+ - "Strainer upstream of each metering device"

+default:

+ - "Liquid line filter-drier"

+ - "Access ports at each unit connection"

+```

+## Where the equipment listing prohibits a field-installed drier, sight glass, or valve in the circuit, that item shall not be installed even if the datasheet selects it, and the Contractor shall report the conflict to the Engineer of Record before the piping is closed.

+## The filter-drier configuration shall be as indicated in the datasheet.

+```datasheet

+label: Filter-Drier Desiccant Configuration

+type: select

+options:

+ - "Solid molecular sieve core"

+ - "Loose-fill desiccant bead"

+ - "Replaceable-core shell"

+default: "Solid molecular sieve core"

+```

+## A drier installed in a circuit that reverses flow shall be bidirectional, or a pair of driers with check valves shall be arranged so that flow passes through a drier in the same direction in both modes.

+## Each filter-drier shall be installed so that it can be replaced without cutting into adjacent piping, and the space required to withdraw or replace it shall be kept clear.

+## Each filter-drier shall be installed with its flow arrow oriented in the direction of flow through that line.

+## A filter-drier shall not be uncapped until the joint that receives it is ready to be made, because the desiccant adsorbs moisture from room air on contact.

+## The line isolation valve arrangement shall be as indicated in the datasheet.

+```datasheet

+label: Refrigerant Line Isolation Valve Provision

+type: select

+options:

+ - "No field isolation valves"

+ - "Isolation valves at the outdoor unit connections"

+ - "Isolation valves at each indoor unit connection"

+ - "Isolation valves at every unit connection"

+ - "Isolation valves at each floor takeoff"

+```

+## Isolation valves reduce the quantity of refrigerant that has to be recovered to service one component and reduce the quantity released by a leak downstream of them, at the cost of additional joints and additional pressure drop. {note}

+## Isolation valves shall be ball or diaphragm valves rated for the design pressure of the section they serve, listed for the refrigerant, and provided with a seal cap over the stem.

+## Isolation valve locations shall be as indicated on [[drawing: the refrigerant piping drawings]].

+## Access ports shall be provided with a seal cap and a valve core rated for the design pressure of the section they serve.

+# Line Sizing and Routing {toc}

+## Line Sizes {toc}

+### Refrigerant line sizes shall be as indicated on [[drawing: the refrigerant piping drawings]].

+### Line sizes shall be confirmed against the equipment manufacturer's published sizing method for the actual equivalent length and elevation difference of each run before any tube is cut.

+### The Contractor shall not substitute a line size, and shall report a conflict between the drawings and the published sizing method to the Engineer of Record before installing the affected run.

+### Undersizing raises pressure drop and lowers capacity; oversizing a vapor line drops the velocity below what carries oil up a riser, so the oil collects at the bottom of the riser instead of returning to the compressor. {note}

+### Vapor risers shall be sized to maintain oil-carrying velocity at the lowest capacity the circuit will run at, not only at design capacity.

+## Equivalent Length and Elevation Limits {toc}

+### The maximum total equivalent line length shall be as indicated in the datasheet.

+```datasheet

+label: Maximum Total Equivalent Refrigerant Line Length

+type: range

+unit: ft

+derived: "the equipment manufacturer's published maximum piping length for the selected system and refrigerant"

+options:

+ min: 25

+ max: 3300

+ setpoints: [25, 50, 100, 165, 250, 400, 550, 750, 1000, 1640, 2200, 3300]

+default: derived

+```

+### The maximum elevation difference between the outdoor unit and any indoor unit shall be as indicated in the datasheet.

+```datasheet

+label: Maximum Vertical Separation Between the Outdoor Unit and Any Indoor Unit

+type: range

+unit: ft

+derived: "the equipment manufacturer's published maximum elevation difference for the selected system and refrigerant"

+options:

+ min: 10

+ max: 360

+ setpoints: [10, 25, 50, 65, 90, 110, 130, 165, 230, 300, 360]

+default: derived

+```

+### The maximum elevation difference between indoor units on one circuit shall be as indicated in the datasheet.

+```datasheet

+label: Maximum Vertical Separation Between Indoor Units

+type: range

+unit: ft

+derived: "the equipment manufacturer's published maximum elevation difference between indoor units on one refrigerant circuit"

+options:

+ min: 0

+ max: 130

+ setpoints: [0, 15, 30, 40, 50, 65, 90, 110, 130]

+default: derived

+```

+### The piping layout shall satisfy every limit stated in this article.

+### These three limits are independent of one another: a run can fall well inside the length limit and still exceed the elevation limit, and a circuit can meet both outdoor-to-indoor limits while separating two indoor units by more than that circuit allows. {note}

+### Where the layout as drawn cannot satisfy every applicable limit, the Contractor shall notify the Engineer of Record before installing the affected piping.

+## Oil Return {toc}

+### The compressor lubricating oil circulates with the refrigerant and depends on vapor velocity to carry it back; wherever the piping gives the oil somewhere to settle and the velocity to leave it there, oil leaves the compressor faster than it returns. {note}

+### The piping shall be arranged so that the oil returns to the compressor at every capacity the circuit is controlled to operate at.

+### The oil-return provisions in the field piping shall be as indicated in the datasheet.

+```datasheet

+label: Riser Oil-Return Provisions

+type: checkbox

+options:

+ - "Trap at the base of each vapor riser"

+ - "Intermediate traps at intervals up tall vapor risers"

+ - "Inverted trap at the top of each vapor riser"

+ - "Double riser on circuits with modulating capacity"

+ - "Horizontal lines pitched in the direction of flow"

+ - "No traps in the field piping"

+```

+### Systems that reclaim oil on a scheduled cycle rather than by continuous entrainment can be harmed by field traps, which hold oil the reclaim cycle was designed to sweep back; systems without such a cycle depend on traps to lift oil up a tall riser in slugs at low load. {note}

+### The Contractor shall confirm the selected oil-return provisions against the equipment manufacturer's published piping arrangement before fabricating any riser, and shall report a conflict to the Engineer of Record before installing it.

+### Where traps are selected, each trap shall be formed from fittings and shall be as short as the fittings allow, so that the trap holds the least oil that still seals.

+### Where horizontal lines are pitched, the pitch shall be continuous and free of intermediate low points.

+## Branch Fittings and Headers {toc}

+### Branch fittings and headers shall be the components published for the system they serve, in the sizes that publication assigns to the connected capacity.

+### Branch fittings shall be installed in the orientation their published installation data requires.

+### A branch fitting shall not be installed in an orientation the published data does not cover.

+### The straight length of tube ahead of and behind each branch fitting shall be not less than the published minimum for that fitting.

+### A branch fitting distributes both refrigerant and the oil traveling with it, and an orientation the fitting was not characterized in sends the liquid and the oil down whichever leg gravity favors instead of splitting them by capacity. {note}

+### Branch and header locations shall be as indicated on [[drawing: the refrigerant piping drawings]].

+# Refrigerant Line Insulation {toc}

+## A vapor line runs below the dew point of the space around it for most of the operating year, so its insulation is doing two jobs at once: limiting heat gain into the refrigerant, and keeping room air away from a cold surface it would condense on. {note}

+## The second job is the one that fails destructively. Heat gain costs capacity; a broken vapor seal drips onto ceilings and equipment and corrodes the tube under the insulation where nobody sees it. {note}

+## Insulation Material {toc}

+### The insulation material shall be as indicated in the datasheet.

+```datasheet

+label: Refrigerant Line Insulation Material

+type: select

+options:

+ - "Flexible elastomeric cellular insulation to ASTM C534"

+ - "Flexible polyolefin cellular insulation to ASTM C1427"

+ - "Rigid phenolic foam insulation to ASTM C1126"

+ - "Cellular glass insulation to ASTM C552"

+ - "Rigid polyisocyanurate insulation to ASTM C591"

+ - "Mineral fiber pipe insulation to ASTM C547"

+default: "Flexible elastomeric cellular insulation to ASTM C534"

+```

+### Closed-cell materials act as their own vapor retarder through the body of the insulation, so the vapor seal on a closed-cell system reduces to the seams and terminations; an open-cell or fibrous material carries no vapor resistance of its own and depends entirely on a continuous applied jacket. {note}

+### Where the datasheet selects a material that is not closed-cell, a vapor retarder jacket conforming to ASTM C1136 shall be applied continuously over the insulation and sealed at every seam, joint, fitting, and termination.

+### Insulation on a line whose surface runs below the dew point shall be installed with a continuous vapor seal from one termination to the other, regardless of the material selected.

+### Insulation shall have a flame spread index of 25 or less and a smoke developed index of 50 or less when tested to ASTM E84, or shall carry a listing for the location it is installed in.

+### Insulation exposed within an air plenum shall carry a listing for plenum use.

+## Insulated Lines and Thickness {toc}

+### The lines to be insulated shall be as indicated in the datasheet.

+```datasheet

+label: Lines Requiring Insulation

+type: checkbox

+options:

+ - "Vapor lines"

+ - "Liquid lines"

+ - "Discharge and hot-gas lines"

+ - "Heat-recovery lines"

+default:

+ - "Vapor lines"

+```

+### On a heat pump the line that carries liquid in cooling carries hot vapor in heating, and on a heat-recovery system a single line carries different conditions at different hours, so the choice of which lines to insulate follows from what each line actually carries across the full operating range rather than from its name. {note}

+### The vapor line insulation wall thickness shall be as indicated in the datasheet.

+```datasheet

+label: Vapor Line Insulation Wall Thickness

+type: range

+unit: in.

+derived: "the minimum thickness [[parameter: adopted-energy-code]] requires for the operating temperature range of the line and the tube outside diameter"

+options:

+ min: 0.375

+ max: 2

+ setpoints: [0.375, 0.5, 0.75, 1, 1.5, 2]

+default: derived

+```

+### The liquid line insulation wall thickness shall be as indicated in the datasheet.

+```datasheet

+label: Liquid Line Insulation Wall Thickness

+type: range

+unit: in.

+options:

+ min: 0

+ max: 1.5

+ setpoints: [0, 0.375, 0.5, 0.75, 1, 1.5]

+```

+### The energy code thickness is a floor and not a design value; a line routed through a space held at a high dew point, or a long run where the accumulated heat gain matters, needs the thickness that keeps the outer surface above the dew point of that space rather than the tabulated minimum. {note}

+### Insulation shall be thickened above the datasheet value wherever the surface temperature at the installed thickness would fall below the dew point of the space the line passes through.

+## Vapor Seal and Application {toc}

+### Insulation shall be slipped over the tube ahead of the final joint wherever the sequence permits, so that the finished sleeve has no longitudinal seam.

+### Insulation slid back to clear a joint being brazed shall be returned into position only after the joint has cooled.

+### Where insulation must be slit to install it, the slit seam and every butt joint shall be adhered continuously with the adhesive published for the material.

+### Insulation shall not be stretched over a fitting or a bend, because stretched material thins at the point of greatest heat gain and pulls open at the seam as it relaxes.

+### Insulation shall be continuous through sleeves, hangers, and penetrations.

+### The vapor seal shall be closed at every termination, including at equipment connections, valves, and access ports, so that no cold tube surface is left exposed to room air.

+### Fittings, valves, and specialties on an insulated line shall be insulated to the same thickness as the adjoining line and sealed into the same vapor seal.

+## Jacketing and Exterior Protection {toc}

+### The protection applied to exposed and exterior insulation shall be as indicated in the datasheet.

+```datasheet

+label: Exterior and Exposed Insulation Protection

+type: select

+options:

+ - "Factory-applied ultraviolet-resistant jacket"

+ - "Field-applied ultraviolet-resistant coating"

+ - "Field-applied aluminum jacket to ASTM B209"

+ - "Field-applied stainless steel jacket to ASTM A240"

+ - "Field-applied PVC jacket"

+```

+### Insulation exposed to sunlight shall be protected by the selected jacket or coating within the time the insulation manufacturer publishes for unprotected exposure.

+### Elastomeric and polyolefin insulations chalk, harden, and crack under ultraviolet exposure, and once the surface cracks the vapor seal is gone even though the insulation is still on the pipe. {note}

+### Jacketing on horizontal exterior runs shall be lapped so that water sheds over the joint rather than into it.

+### Insulation exposed where it can be struck, walked on, or leaned against shall be protected by a jacket or guard that carries the impact without transmitting it to the insulation.

+# Supports, Anchors, and Seismic Restraint {toc}

+## Support Spacing {toc}

+### Piping shall be supported at intervals not exceeding the values in the following table, and shall in addition be supported at every change of direction and within 12 in. of each in-line specialty:

+| Tube | Maximum horizontal spacing | Maximum vertical spacing |

+|------|---------------------------|--------------------------|

+| Drawn temper, 1-3/8 in. OD and smaller | 6 ft | 10 ft |

+| Drawn temper, larger than 1-3/8 in. OD | 10 ft | 10 ft |

+| Annealed temper, all sizes | 4 ft | 8 ft |

+### Support spacing shall be reduced below the tabulated value wherever the run carries a concentrated load or where the deflection between supports would create a low point in a line that has to drain.

+### Vertical runs shall be supported at each floor penetrated and at the tabulated interval within a single-story rise.

+## Support Materials and Isolation {toc}

+### Supports, hangers, and attachments shall be MSS SP-58 components selected for the load, the tube size, and the exposure.

+### The support finish shall be as indicated in the datasheet.

+```datasheet

+label: Hanger and Support Finish

+type: select

+options:

+ - "Electro-galvanized steel"

+ - "Hot-dip galvanized steel"

+ - "Type 304 stainless steel"

+ - "Type 316 stainless steel"

+ - "Epoxy-coated steel"

+ - "Copper-plated steel"

+```

+### Supports in exterior, high-humidity, and chemically aggressive locations shall be furnished in a finish rated for that exposure, and an electro-galvanized finish shall not be used in those locations.

+### Copper tube shall be separated from a support of dissimilar metal by a dielectric isolator, a coated hanger, or a non-metallic insert.

+### Supports on an insulated line shall bear on a rigid insert or a protection shield sized for the insulation thickness.

+### An insert or shield shall carry the load across the full arc it bears on, so that the insulation is not compressed and the vapor seal is not broken at the support.

+### A support that pinches insulation creates a cold bridge exactly where the insulation is thinnest, and that point condenses first and corrodes the tube under the hanger. {note}

+## Vibration Isolation {toc}

+### The connection between the field piping and each compressor-bearing unit shall include the vibration provision the equipment requires, so that compressor vibration is not carried into the field joints.

+### Piping shall not be rigidly anchored to a structure in a way that transfers building movement or equipment vibration into a joint.

+### Piping shall be supported so that no part of the weight of the field piping bears on an equipment connection.

+## Seismic Restraint {toc}

+### The seismic restraint of refrigerant piping shall be as indicated in the datasheet.

+```datasheet

+label: Seismic Restraint of Refrigerant Piping

+type: select

+derived: "[[parameter: seismic-design-category]] applied to the size, weight, and location of each run"

+options:

+ - "No seismic restraint required"

+ - "Transverse and longitudinal bracing in accordance with ASCE 7 Chapter 13"

+ - "Bracing in accordance with a pre-approved seismic restraint guideline listed for the piping"

+default: derived

+```

+### Where restraint is required, the restraint spacing, the attachment to structure, and the flexibility provided at seismic joints and at equipment connections shall be shown on the coordination layout before installation begins.

+### Seismic restraint shall not be attached to a support that also serves as a thermal anchor unless the combined load has been accounted for.

+# Penetrations and Firestopping {toc}

+## Sleeves {toc}

+### Piping passing through a wall, floor, or roof shall pass through a sleeve.

+### The sleeve material shall be as indicated in the datasheet.

+```datasheet

+label: Sleeve Material

+type: select

+options:

+ - "Schedule 40 steel pipe"

+ - "Galvanized sheet steel"

+ - "Copper tube"

+ - "PVC pipe"

+ - "Molded plastic sleeve"

+```

+### Sleeves shall be sized to pass the insulated tube without compressing the insulation and without transferring the weight of the tube to the sleeve.

+### Sleeves in a fire-rated assembly shall be the material and configuration the tested firestop system requires, regardless of the datasheet selection.

+### Sleeves through a floor shall extend above the finished floor by the height the adopted code requires, and the annular space shall be sealed against the passage of water.

+### Sleeves in an exterior wall or roof shall be sealed and flashed so that water is kept out of the assembly.

+## Firestop Systems {toc}

+### Penetrations of fire-rated walls, floors, and ceilings shall be sealed with a firestop system tested to ASTM E814 and listed for insulated copper tube through an assembly of the rating being penetrated, in accordance with [[sync/firestopping]].

+### The firestop system type shall be as indicated in the datasheet.

+```datasheet

+label: Firestop System Type

+type: select

+derived: "the tested and listed system covering insulated copper tube of the installed size through an assembly of the rating being penetrated"

+options:

+ - "Intumescent wrap strip"

+ - "Intumescent collar"

+ - "Firestop sealant over mineral wool packing"

+ - "Cast-in-place firestop device"

+ - "Firestop pillow assembly"

+default: derived

+```

+### Combustible insulation left continuous through a rated penetration burns out of the opening and leaves an unobstructed hole, which is why the listed system for an insulated tube almost always includes an intumescent element sized for the insulation rather than for the tube. {note}

+### Insulation shall not be interrupted at a rated penetration except where the tested system being used requires the interruption.

+### The listing designation of the system installed at each rated penetration shall be recorded and submitted with the closeout documents.

+# Refrigerant Safety Provisions {toc}

+## Refrigerant Concentration Limits {toc}

+### Where any part of the system serves or passes through an occupied space, the system charge shall be limited so that a release of the full charge into the smallest occupied space the system serves stays within the limit ASHRAE 15 or ASHRAE 15.2 establishes for the refrigerant safety group, or mitigation shall be provided in accordance with that standard.

+### The compliance basis shall be as indicated in the datasheet.

+```datasheet

+label: Refrigerant Concentration Compliance Basis

+type: select

+derived: "the total system refrigerant charge compared against the volume of the smallest occupied space the system serves"

+options:

+ - "Charge limited so a full release stays within the applicable limit"

+ - "Charge above the applicable limit with detection and mitigation provided"

+ - "No part of the system serves or passes through an occupied space"

+default: derived

+```

+### For a refrigerant in a nonflammable safety group the governing number is a toxicity-based concentration limit; for a refrigerant in a mildly flammable safety group it is a fraction of the lower flammability limit, and the two are arrived at differently even though both are expressed as a concentration. {note}

+### The field piping adds refrigerant to the circuit, so the Contractor shall compute the compliance check using the total charge actually weighed in rather than the base charge alone.

+### The Contractor shall report a computed charge that exceeds the applicable limit to the Engineer of Record before charging, so that the mitigation or the reconfiguration can be resolved before refrigerant is in the system.

+## Refrigerant Detection and Mitigation {toc}

+### The detection and mitigation components shall be as indicated in the datasheet.

+```datasheet

+label: Refrigerant Detection and Mitigation Components

+type: checkbox

+options:

+ - "Refrigerant detection sensors listed to UL 60335-2-40"

+ - "Interlock to the indoor unit circulation fan"

+ - "Interlock to a dedicated mechanical ventilation fan"

+ - "Automatic shutoff valves that isolate the released charge"

+ - "Audible and visual occupant alarm"

+ - "Alarm annunciation to the building automation system"

+```

+### The detection alarm set point shall be as indicated in the datasheet.

+```datasheet

+label: Refrigerant Detection Alarm Set Point

+type: range

+unit: '% LFL'

+options:

+ min: 5

+ max: 25

+ setpoints: [5, 10, 15, 20, 25]

+default: 25

+```

+### A set point at the ceiling the safety standard permits gives the longest interval before a nuisance alarm; a lower set point starts the mitigation earlier in a release and is used where the space is hard to evacuate or the ventilation takes time to establish flow. {note}

+### Detection sensors shall be located near the floor of the space they monitor and at the position within the space the equipment listing requires.

+### The refrigerants this standard covers are heavier than air at room conditions and collect at floor level, so a sensor mounted at ceiling height reports a release only after the space below it has already filled. {note}

+### On alarm, the mitigation action shall start automatically without any manual step.

+### The mitigation action shall continue until the measured concentration falls below the set point and shall not be capable of being defeated at the device.

+### Detection, alarm, interlock, and shutoff wiring shall comply with NFPA 70.

+### Sensors shall be installed with the date of installation recorded on the device and the end of the published service life recorded in the closeout documents.

+### Detection and mitigation shall be demonstrated to operate as designed before the system is accepted, and the demonstration shall be witnessed and recorded.

+## Piping in Occupied and Concealed Spaces {toc}

+### Piping routed through an occupied space shall be protected from mechanical damage over its full exposed length.

+### Piping routed through a shaft, plenum, or concealed space shall be arranged so that a release in that space is carried to where it is detected rather than accumulating out of reach.

+### A refrigerant line shall not be routed through an exit stair enclosure, an exit passageway, or an elevator hoistway except where the adopted code expressly permits it.

+# Piping Identification {toc}

+## Refrigerant piping shall be identified at each side of every wall, floor, and ceiling penetration, at each unit connection, at each valve, and at intervals not exceeding 20 ft along every exposed and accessible run.

+## The identification content shall be as indicated in the datasheet.

+```datasheet

+label: Refrigerant Piping Identification Content

+type: checkbox

+options:

+ - "Refrigerant designation"

+ - "Refrigerant safety group"

+ - "Flammable refrigerant warning marking"

+ - "Line service designation"

+ - "Direction of flow"

+ - "System or circuit identifier"

+default:

+ - "Refrigerant designation"

+ - "Line service designation"

+ - "Direction of flow"

+ - "System or circuit identifier"

+```

+## Where the system carries a refrigerant in a flammable safety group, the flammable refrigerant marking required by the adopted code and by ASHRAE 15 or 15.2 shall be applied in addition to whatever the datasheet selects.

+## Markers shall be applied to the outside of the insulation jacket where the line is insulated, and shall be legible from the position from which the line is normally approached.

+# Installation {toc}

+## Protection of the Tube Bore {toc}

+### Tube shall be kept capped and under its nitrogen holding charge until the moment the end is prepared for a joint.

+### An open tube end shall be recapped or plugged whenever work on that run stops.

+### Tube ends shall be cut square with a tube cutter and reamed to remove the inside burr.

+### Tube shall be cut, reamed, and cleaned so that no filings, chips, or abrasive residue enter the bore.

+### Tube shall not be cut with an abrasive wheel or a saw that leaves particulate in the bore.

+### A run that has been left open to ambient air long enough to admit visible moisture, dust, or construction debris shall be cleaned or replaced before it is joined into the circuit, and the Engineer of Record shall make the initial determination where the parties disagree whether cleaning is sufficient.

+## Dry-Nitrogen Purge During Brazing {toc}

+### The interior of the tube shall be purged with a low positive flow of oil-free dry nitrogen throughout the heating of every brazed joint and until that joint has cooled.

+### The purge flow rate shall be as indicated in the datasheet.

+```datasheet

+label: Brazing Purge Nitrogen Flow Rate

+type: range

+unit: cfh

+options:

+ min: 1

+ max: 10

+ setpoints: [1, 2, 3, 4, 5, 8, 10]

+default: 3

+```

+### The purge shall be regulated to a flow that displaces the air in the tube without pressurizing the joint being made.

+### A purge strong enough to raise pressure behind the joint blows through the molten filler metal and leaves a void in place of the fillet, so the flow that protects the bore and the flow that ruins the joint are separated by a fairly narrow margin. {note}

+### Copper heated to brazing temperature in the presence of air grows a black flaky oxide on the inside of the tube; that scale breaks loose once refrigerant and oil are flowing, travels to the metering device and the compressor, and does damage that no later cleaning of the system reverses. {note}

+### Oxygen, carbon dioxide, and compressed shop air shall not be used as the purge gas.

+### A purge point and a vent point shall be established on each run being brazed so that the nitrogen flows past every joint being made rather than dead-ending at one of them.

+## Brazing Procedure {toc}

+### Joint members shall be cleaned of oxide and handling residue immediately before assembly.

+### The tube shall be inserted into the fitting socket to the full depth the fitting provides.

+### The joint shall be heated uniformly around its circumference to the brazing temperature of the filler metal being used.

+### Filler metal shall be applied at the mouth of the socket and drawn into the joint by capillary action rather than being deposited as a bead on the outside.

+### Heat shall be removed as soon as the fillet is complete, and the joint shall not be overheated.

+### Overheating erodes the base metal at the socket mouth, burns the phosphorus out of the filler, and scorches insulation and adjacent construction; the joint that results looks finished and fails under vibration. {note}

+### Combustible surfaces near a joint being brazed shall be shielded, and hot work shall be conducted under the site hot work procedure in force.

+## Routing and Clearances {toc}

+### Piping shall be routed so that every valve, access port, filter-drier, and detection sensor remains reachable for service without removing permanent construction.

+### Piping shall be routed clear of the service access the connected equipment requires.

+### Piping shall not be routed where it would be exposed to a heat source that raises the surface temperature of an uninsulated line above the temperature the system was designed around.

+### Piping shall not be routed in contact with another pipe, duct, conduit, or structural member in a way that prevents the insulation from being continuous.

+### Coordination of routing, penetrations, and support locations shall be completed on the coordination layout before rough-in, and shall be coordinated with [[sync/building-thermal-insulation]] and [[sync/firestopping]].

+# Testing {toc}

+## Pressure and Leak Test {toc}

+### The field piping shall be pressure-tested after brazing is complete and before evacuation, insulation, and the closing of penetrations.

+### The test medium shall be as indicated in the datasheet.

+```datasheet

+label: Pressure Test Medium

+type: select

+options:

+ - "Oil-free dry nitrogen"

+ - "Oil-free dry nitrogen with a trace charge of the system refrigerant"

+default: "Oil-free dry nitrogen"

+```

+### Oxygen and compressed shop air shall not be used as a test medium, and the system shall not be blown out with either.

+### Oxygen in contact with the residual oil in a refrigerant circuit under pressure is an ignition hazard, and shop air carries both moisture and compressor oil into the bore the rest of this standard exists to keep clean. {note}

+### The high side test pressure shall be as indicated in the datasheet.

+```datasheet

+label: High-Side Pressure Test Pressure

+type: range

+unit: psig

+derived: "the high side design pressure, limited to the lowest pressure rating among the components left in the circuit during the test"

+options:

+ min: 100

+ max: 800

+ setpoints: [100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800]

+default: derived

+```

+### The low side test pressure shall be as indicated in the datasheet.

+```datasheet

+label: Low-Side Pressure Test Pressure

+type: range

+unit: psig

+derived: "the low side design pressure, limited to the lowest pressure rating among the components left in the circuit during the test"

+options:

+ min: 100

+ max: 600

+ setpoints: [100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600]

+default: derived

+```

+### Equipment and specialties whose rating is below the test pressure shall be isolated or removed before the test rather than being exposed to it.

+### The pressure test hold duration shall be as indicated in the datasheet.

+```datasheet

+label: Pressure Test Hold Duration

+type: range

+unit: hours

+options:

+ min: 1

+ max: 48

+ setpoints: [1, 2, 4, 8, 12, 24, 48]

+```

+### A short hold finds a leak large enough to move the gauge quickly and lets the sequence continue the same day; a long hold finds a slow leak that a short hold cannot separate from instrument error, at the cost of a day in the schedule and a wider ambient temperature swing to correct for. {note}

+### The gauge pressure and the ambient temperature at the tube shall be recorded at the start and at the end of the hold, and the observed pressure change shall be corrected for the temperature change before the result is judged.

+### Nitrogen pressure moves with temperature independently of any leak, so an uncorrected reading on a system that cooled overnight reports a leak that is not there, and one that warmed overnight hides a leak that is. {note}

+### A pressure change that remains after temperature correction shall be treated as a leak.

+## Leak Location and Repair {toc}

+### The leak location methods permitted on the project shall be as indicated in the datasheet.

+```datasheet

+label: Permitted Leak Location Methods

+type: checkbox

+options:

+ - "Electronic refrigerant leak detector"

+ - "Bubble-forming leak detection solution"

+ - "Ultrasonic leak detector"

+ - "Fluorescent tracer dye"

+default:

+ - "Electronic refrigerant leak detector"

+ - "Bubble-forming leak detection solution"

+```

+### An electronic detector requires a detectable gas in the circuit, so where the datasheet selects nitrogen alone as the test medium a bubble solution or an ultrasonic detector is the method that applies to that test. {note}

+### Fluorescent tracer dye shall not be introduced into a circuit whose equipment listing prohibits it.

+### A leaking joint shall be depressurized, cut out, and remade, and shall not be repaired by adding filler metal to a joint under pressure.

+### A leak sealant shall not be introduced into the system.

+### The circuit shall be retested in full after a repair, and the cost of the repair and of every repeated test shall be borne by the Contractor.

+## Evacuation {toc}

+### The test medium shall be recovered or vented in accordance with 40 CFR Part 82 Subpart F before evacuation begins.

+### The system shall be evacuated through both the high side and the low side service connections, using large-bore hoses or a core removal tool so that the service valve cores do not throttle the pump.

+### The evacuation target shall be as indicated in the datasheet.

+```datasheet

+label: Evacuation Target Absolute Pressure

+type: range

+unit: microns

+options:

+ min: 100

+ max: 1500

+ setpoints: [100, 200, 250, 300, 500, 750, 1000, 1500]

+default: 500

+```

+### The evacuation method shall be as indicated in the datasheet.

+```datasheet

+label: Evacuation Method

+type: select

+options:

+ - "Single evacuation to the target"

+ - "Double evacuation with one dry-nitrogen break"

+ - "Triple evacuation with two dry-nitrogen breaks"

+default: "Triple evacuation with two dry-nitrogen breaks"

+```

+### Water boils slowly at low absolute pressure, so a single long pulldown removes free moisture far less effectively than breaking the vacuum with dry nitrogen and pulling down again, which dilutes and sweeps the vapor out with each cycle. {note}

+### Each vacuum break shall be made with oil-free dry nitrogen and shall raise the system to a positive pressure before the next pulldown begins.

+### The absolute pressure shall be read with a micron gauge connected to the system rather than to the pump, so that the reading is of the system and not of the pump inlet.

+### Evacuation shall not be used to remove a leak, and a system that will not reach the target shall be returned to the pressure test rather than being evacuated for a longer period.

+## Standing Vacuum Decay Test {toc}

+### After the target is reached, the system shall be isolated from the vacuum pump with the micron gauge left reading the system, and held.

+### The decay hold duration shall be as indicated in the datasheet.

+```datasheet

+label: Standing Vacuum Decay Hold Duration

+type: range

+unit: minutes

+options:

+ min: 5

+ max: 120

+ setpoints: [5, 10, 15, 20, 30, 45, 60, 120]

+default: 15

+```

+### The maximum rise permitted during the hold shall be as indicated in the datasheet.

+```datasheet

+label: Maximum Vacuum Rise Permitted During the Decay Hold

+type: range

+unit: microns

+options:

+ min: 0

+ max: 1000

+ setpoints: [0, 50, 100, 150, 200, 250, 500, 1000]

+default: 500

+```

+### A rise that climbs steadily and does not level off indicates a leak; a rise that levels off at a higher value indicates moisture still off-gassing inside the system, and the two call for different corrections. {note}

+### A system that fails the decay test because the rise did not stabilize shall be returned to the pressure test.

+### A system that fails the decay test because the rise stabilized above the permitted value shall be evacuated again.

+### Refrigerant shall not be introduced into a system that has not passed the decay test.

+# Charging {toc}

+## The charging method shall be as indicated in the datasheet.

+```datasheet

+label: Charging Method

+type: select

+options:

+ - "Weighed charge computed from the base charge and the line-length addition"

+ - "Weighed base charge trimmed to the published subcooling target"

+ - "Weighed base charge trimmed to the published superheat target"

+ - "Automatic charge determination by the equipment control"

+default: "Weighed charge computed from the base charge and the line-length addition"

+```

+## The line-length addition shall be computed from the installed liquid line size and length using the equipment manufacturer's published charge table, and the computation shall be recorded with its inputs.

+## Charge shall be weighed in with a charging scale and the weight recorded, and the system shall not be charged by gauge pressure or by sight glass appearance alone where a weighed charge applies.

+## A blended refrigerant shall be drawn from the cylinder as liquid, so that the composition entering the system matches the composition in the cylinder.

+## The components of a zeotropic blend boil off at different rates, so drawing vapor from the cylinder removes the lighter component first and leaves both the cylinder and the system holding something other than the refrigerant on the label. {note}

+## Charging shall not begin until the pressure test and the decay test have been passed and the results recorded.

+## Refrigerant cylinders shall be weighed before and after charging, and the net weight from the cylinder shall be reconciled against the weight recorded as charged into the system.

+## Refrigerant recovered during the work shall be recovered into a recovery cylinder rated for that refrigerant and shall be disposed of or reclaimed in accordance with 40 CFR Part 82 Subpart F.

+# Delivery, Storage, and Handling {toc}

+## Tube shall be delivered with both ends capped and with the nitrogen holding charge intact, and a length delivered with a cap missing or a holding charge lost shall be rejected or restored to that condition before use.

+## Tube, fittings, filter-driers, and specialties shall be stored under cover, off the ground, and clear of standing water.

+## Insulation shall be stored under cover and shall be kept dry, because a material that has absorbed water carries that water into the vapor seal when it is installed.

+## Insulation adhesives and coatings shall be stored within the temperature range published for the product.

+## Refrigerant cylinders shall be stored upright, secured against falling, protected from direct sunlight, and kept below the maximum storage temperature marked on the cylinder.

+## Cylinders of a refrigerant in a flammable safety group shall be stored in a ventilated location away from ignition sources and shall not be stored in an exit path or an unventilated interior room.

+## Materials damaged in transit, in storage, or in handling shall be replaced rather than repaired, unless the Engineer of Record accepts a specific repair in writing.

+# Warranty {toc}

+## The Contractor shall warrant the refrigerant piping installation against leaks and against defects in materials and workmanship for the period indicated in the datasheet, measured from the date of substantial completion.

+```datasheet

+label: Refrigerant Piping Warranty Period

+type: range

+unit: years

+options:

+ min: 1

+ max: 5

+ setpoints: [1, 2, 3, 5]

+default: 1

+```

+## Where the contract documents state a longer warranty period than the datasheet, the longer period shall govern.

+## A leak at a field joint, and an equipment failure attributable to contamination, moisture, incorrect charge, or a piping arrangement outside the published limits, shall be corrected at the Contractor's expense.

+## The Contractor's cost of a warranty correction shall include recovery and replacement of the refrigerant, replacement of contaminated refrigerant and oil, removal and replacement of insulation and of any firestop system disturbed, and repair of finishes damaged in gaining access.

+## Work performed under this warranty shall itself be warranted for a full new term equal to the original period measured from the date the correction is completed, or for the remainder of the original period, whichever ends later.

+## The Contractor shall not take an action under this standard that voids the equipment manufacturer's warranty, and shall observe the published sizing, length, elevation, evacuation, and charging requirements on which that warranty depends.

+# Spare Parts {toc}

+## 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

+type: checkbox

+options:

+ - "One replacement filter-drier core for each installed replaceable-core shell"

+ - "One replacement refrigerant detection sensor for each system"

+ - "One unopened container of insulation seam adhesive"

+ - "One replacement seal cap for each access port and isolation valve"

+```

+## Spare parts shall be the same make and model as the installed items and shall be delivered in their original unopened packaging.

+## Spare parts shall be labeled with the item they serve and with the system or circuit identifier used on the piping identification markers.

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