Refrigerant Piping
Corpus sync: neutrality remakes, note hygiene, datasheet relocation, transformer-split cross-refs
Showing changes from Rev 5
to Rev 6
in Refrigerant Piping.
---
title: Refrigerant Piping
…120 unchanged lines
- 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)]
+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)"
```
…37 unchanged lines
### 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}
−```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"
−```
+### 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
…6 unchanged lines
```
+```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}
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### 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.
−# Materials {toc}
+# ACR Copper Tube {toc}
−## ACR Copper Tube {toc}
−
```datasheet
label: Copper Tube Standard
…15 unchanged lines
```
−### Refrigerant piping shall be seamless copper tube manufactured for air-conditioning and refrigeration field service in accordance with ASTM B280.
+## 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}
+## 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.
+## 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.
+## 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}
+## 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.
+## 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.
+## Soft tube shall not be used for long unsupported runs where it would sag and trap oil.
−## Joints and Fittings {toc}
+# Joints and Fittings {toc}
```datasheet
…7 unchanged lines
```
−### 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).
+## 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.
+## 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.
+## 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}
+# Brazing Filler Metal {toc}
```datasheet
…6 unchanged lines
```
−### Brazing filler metal shall conform to AWS A5.8.
+## 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-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.
+## 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.
+## Cadmium-bearing filler metals shall not be used.
−### Where flux is used, all flux residue shall be removed after brazing because it is corrosive.
+## Where flux is used, all flux residue shall be removed after brazing because it is corrosive.
−## Refrigerant Line Insulation {toc}
+# Refrigerant Line Insulation {toc}
```datasheet
…26 unchanged lines
```
−### Suction (and where present, any cold) refrigerant lines shall be insulated with preformed flexible elastomeric cellular (closed-cell) insulation conforming to ASTM C534.
+## 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}
+## 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 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 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.
+## 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 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.
+## 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}
…165 unchanged lines
# Insulation {toc}
−## Application {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.
−### 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.
−### 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.
−### 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}
…108 unchanged lines
- "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"
+default: "Hold isolated for 15 minutes; rise to no more than 500 microns and stabilizing (standard)"
```
…25 unchanged lines
# Installation {toc}
−## General {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.
−### 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.
−### 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.
−### 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}
…21 unchanged lines
### 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.