1 Scope

NOTE 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. (1.1)

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. (1.2)

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. (1.3)

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. (1.4)

NOTE The following are governed elsewhere and are outside this standard: (1.5)

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

1.6 Refrigerant piping shall be routed as indicated on the mechanical plans.

1.7 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.

1.8 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.

NOTE 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. (1.9)

2 Referenced Standards

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

2.2 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

3 Submittals

3.1 Action Submittals

3.1.1 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

Action Submittal Packagecheckbox

☐ 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

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

3.2 Informational Submittals

3.2.1 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

Informational Submittal Packagecheckbox

☐ 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

3.3 Closeout Submittals

3.3.1 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

Closeout Submittal Packagecheckbox

☐ 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

4 Quality Assurance

4.1 Brazing Qualification

4.1.1 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.

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

4.1.3 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.

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

4.1.5 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.

4.2 Refrigerant Handling Certification

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

4.2.2 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.

4.2.3 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.

4.3 Visual Examination of Brazed Joints

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

NOTE 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. (4.3.2)

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

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

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

5 Refrigerant and Safety Classification

NOTE 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. (5.1)

5.2 The refrigerant shall be as indicated in the datasheet.

Refrigerant Designation (ASHRAE 34)select

R-410A

R-454B

R-32

R-466A

R-407C

R-448A

R-449A

R-513A

R-134a

R-1234ze(E)

R-22

Per drawings — the mechanical equipment schedule (deferred by default)

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

Refrigerant Safety Group (ASHRAE 34)select

A1

A2L

A2

A3

B1

B2L

B2

B3

Derived — the safety classification ASHRAE 34 publishes for the selected refrigerant designation (by default)

NOTE 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. (5.4)

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. (5.5)

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

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

5.8 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.

6 Design Pressure

6.1 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.

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

High-Side Design Pressurerange

psig

150200250300350400450500550600650700750800

Derived — the saturation pressure of the selected refrigerant at the highest temperature the high side will reach, determined in accordance with ASHRAE 15 and taken not lower than the maximum allowable pressure marked on the equipment (by default)

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

Low-Side Design Pressurerange

psig

100150200250300350400450500550600

Derived — the saturation pressure of the selected refrigerant at the highest temperature the low side will reach while the system is idle, determined in accordance with ASHRAE 15 and taken not lower than the maximum allowable pressure marked on the equipment (by default)

NOTE 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. (6.4)

6.5 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.

7 Tube

7.1 Tube Material and Product Standard

7.1.1 Refrigerant tube shall be as indicated in the datasheet.

Tube Material and Product Standardselect

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

NOTE 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. (7.1.2)

7.1.3 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.

7.1.4 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.

7.1.5 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.

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

7.2 Temper and Form

NOTE 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. (7.2.1)

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

Permitted Tube Temperscheckbox

☑ Drawn temper straight length

☑ Annealed temper coil

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

Largest Tube Outside Diameter Permitted in Annealed Temperrange

in.

0.3750.50.6250.750.8751.1251.3751.625

NOTE 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. (7.2.4)

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

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

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

8 Joints and Fittings

8.1 Permitted Joining Methods

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

Permitted Joining Methodscheckbox

☑ Brazed socket joint

☐ Refrigerant-rated press-connect joint

☑ Refrigerant-rated flare joint

☐ Refrigerant-rated bite-type mechanical joint

☐ Refrigerant-rated push-to-connect joint

NOTE 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. (8.1.2)

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

8.1.4 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.

8.1.5 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.

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

8.2 Joints in Concealed and Inaccessible Locations

NOTE 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. (8.2.1)

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

Joining Methods Permitted in Concealed and Inaccessible Locationscheckbox

☑ Brazed socket joint

☐ Refrigerant-rated press-connect joint

☐ Refrigerant-rated flare joint

☐ Refrigerant-rated bite-type mechanical joint

☐ Refrigerant-rated push-to-connect joint

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

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

8.3 Fittings

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

Permitted Braze-Joint Fitting Standardscheckbox

☑ 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

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

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

8.3.4 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.

8.4 Brazing Filler Metal

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

Filler Metal Classification for Copper-to-Copper Jointsselect

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

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

Filler Metal Classification for Copper-to-Brass and Copper-to-Bronze Jointsselect

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

NOTE 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. (8.4.3)

8.4.4 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.

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

8.4.6 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.

8.4.7 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.

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

9 Field-Installed Refrigerant Specialties

NOTE 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. (9.1)

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

Field-Installed Refrigerant Specialtiescheckbox

☑ 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

9.3 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.

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

Filter-Drier Desiccant Configurationselect

Solid molecular sieve core

Loose-fill desiccant bead

Replaceable-core shell

9.5 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.

9.6 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.

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

9.8 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.

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

Refrigerant Line Isolation Valve Provisionselect

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

NOTE 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. (9.10)

9.11 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.

9.12 Isolation valve locations shall be as indicated on the refrigerant piping drawings.

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

10 Line Sizing and Routing

10.1 Line Sizes

10.1.1 Refrigerant line sizes shall be as indicated on the refrigerant piping drawings.

10.1.2 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.

10.1.3 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.

NOTE 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. (10.1.4)

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

10.2 Equivalent Length and Elevation Limits

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

Maximum Total Equivalent Refrigerant Line Lengthrange

ft

25501001652504005507501000164022003300

Derived — the equipment manufacturer's published maximum piping length for the selected system and refrigerant (by default)

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

Maximum Vertical Separation Between the Outdoor Unit and Any Indoor Unitrange

ft

1025506590110130165230300360

Derived — the equipment manufacturer's published maximum elevation difference for the selected system and refrigerant (by default)

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

Maximum Vertical Separation Between Indoor Unitsrange

ft

153040506590110130

Derived — the equipment manufacturer's published maximum elevation difference between indoor units on one refrigerant circuit (by default)

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

NOTE 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. (10.2.5)

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

10.3 Oil Return

NOTE 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. (10.3.1)

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

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

Riser Oil-Return Provisionscheckbox

☐ 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

NOTE 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. (10.3.4)

10.3.5 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.

10.3.6 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.

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

10.4 Branch Fittings and Headers

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

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

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

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

NOTE 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. (10.4.5)

10.4.6 Branch and header locations shall be as indicated on the refrigerant piping drawings.

11 Refrigerant Line Insulation

NOTE 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. (11.1)

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. (11.2)

11.3 Insulation Material

11.3.1 The insulation material shall be as indicated in the datasheet.

Refrigerant Line Insulation Materialselect

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

NOTE 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. (11.3.2)

11.3.3 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.

11.3.4 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.

11.3.5 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.

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

11.4 Insulated Lines and Thickness

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

Lines Requiring Insulationcheckbox

☑ Vapor lines

☐ Liquid lines

☐ Discharge and hot-gas lines

☐ Heat-recovery lines

NOTE 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. (11.4.2)

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

Vapor Line Insulation Wall Thicknessrange

in.

0.3750.50.7511.52

Derived — the minimum thickness Adopted Energy CodeAdopted Energy CodeParameterEach project supplies its own value.adopted-energy-code requires for the operating temperature range of the line and the tube outside diameter (by default)

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

Liquid Line Insulation Wall Thicknessrange

in.

0.3750.50.7511.5

NOTE 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. (11.4.5)

11.4.6 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.

11.5 Vapor Seal and Application

11.5.1 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.

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

11.5.3 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.

11.5.4 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.

11.5.5 Insulation shall be continuous through sleeves, hangers, and penetrations.

11.5.6 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.

11.5.7 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.

11.6 Jacketing and Exterior Protection

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

Exterior and Exposed Insulation Protectionselect

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

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

NOTE 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. (11.6.3)

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

11.6.5 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.

12 Supports, Anchors, and Seismic Restraint

12.1 Support Spacing

12.1.1 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

12.1.2 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.

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

12.2 Support Materials and Isolation

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

12.2.2 The support finish shall be as indicated in the datasheet.

Hanger and Support Finishselect

Electro-galvanized steel

Hot-dip galvanized steel

Type 304 stainless steel

Type 316 stainless steel

Epoxy-coated steel

Copper-plated steel

12.2.3 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.

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

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

12.2.6 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.

NOTE 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. (12.2.7)

12.3 Vibration Isolation

12.3.1 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.

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

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

12.4 Seismic Restraint

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

Seismic Restraint of Refrigerant Pipingselect

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

Derived — Seismic Design CategorySeismic Design CategoryParameterEach project supplies its own value.seismic-design-category applied to the size, weight, and location of each run (by default)

12.4.2 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.

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

13 Penetrations and Firestopping

13.1 Sleeves

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

13.1.2 The sleeve material shall be as indicated in the datasheet.

Sleeve Materialselect

Schedule 40 steel pipe

Galvanized sheet steel

Copper tube

PVC pipe

Molded plastic sleeve

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

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

13.1.5 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.

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

13.2 Firestop Systems

13.2.1 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 FirestoppingFirestoppingResolves to the current edition.sync/firestopping.

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

Firestop System Typeselect

Intumescent wrap strip

Intumescent collar

Firestop sealant over mineral wool packing

Cast-in-place firestop device

Firestop pillow assembly

Derived — the tested and listed system covering insulated copper tube of the installed size through an assembly of the rating being penetrated (by default)

NOTE 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. (13.2.3)

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

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

14 Refrigerant Safety Provisions

14.1 Refrigerant Concentration Limits

14.1.1 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.

14.1.2 The compliance basis shall be as indicated in the datasheet.

Refrigerant Concentration Compliance Basisselect

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

Derived — the total system refrigerant charge compared against the volume of the smallest occupied space the system serves (by default)

NOTE 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. (14.1.3)

14.1.4 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.

14.1.5 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.

14.2 Refrigerant Detection and Mitigation

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

Refrigerant Detection and Mitigation Componentscheckbox

☐ 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

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

Refrigerant Detection Alarm Set Pointrange

% LFL

510152025

NOTE 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. (14.2.3)

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

NOTE 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. (14.2.5)

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

14.2.7 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.

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

14.2.9 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.

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

14.3 Piping in Occupied and Concealed Spaces

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

14.3.2 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.

14.3.3 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.

15 Piping Identification

15.1 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.

15.2 The identification content shall be as indicated in the datasheet.

Refrigerant Piping Identification Contentcheckbox

☑ Refrigerant designation

☐ Refrigerant safety group

☐ Flammable refrigerant warning marking

☑ Line service designation

☑ Direction of flow

☑ System or circuit identifier

15.3 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.

15.4 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.

16 Installation

16.1 Protection of the Tube Bore

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

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

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

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

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

16.1.6 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.

16.2 Dry-Nitrogen Purge During Brazing

16.2.1 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.

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

Brazing Purge Nitrogen Flow Raterange

cfh

12345810

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

NOTE 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. (16.2.4)

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. (16.2.5)

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

16.2.7 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.

16.3 Brazing Procedure

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

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

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

16.3.4 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.

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

NOTE 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. (16.3.6)

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

16.4 Routing and Clearances

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

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

16.4.3 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.

16.4.4 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.

16.4.5 Coordination of routing, penetrations, and support locations shall be completed on the coordination layout before rough-in, and shall be coordinated with Building Thermal InsulationBuilding Thermal InsulationResolves to the current edition.sync/building-thermal-insulation and FirestoppingFirestoppingResolves to the current edition.sync/firestopping.

17 Testing

17.1 Pressure and Leak Test

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

17.1.2 The test medium shall be as indicated in the datasheet.

Pressure Test Mediumselect

Oil-free dry nitrogen

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

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

NOTE 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. (17.1.4)

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

High-Side Pressure Test Pressurerange

psig

100150200250300350400450500550600650700750800

Derived — the high side design pressure, limited to the lowest pressure rating among the components left in the circuit during the test (by default)

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

Low-Side Pressure Test Pressurerange

psig

100150200250300350400450500550600

Derived — the low side design pressure, limited to the lowest pressure rating among the components left in the circuit during the test (by default)

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

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

Pressure Test Hold Durationrange

hours

1248122448

NOTE 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. (17.1.9)

17.1.10 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.

NOTE 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. (17.1.11)

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

17.2 Leak Location and Repair

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

Permitted Leak Location Methodscheckbox

☑ Electronic refrigerant leak detector

☑ Bubble-forming leak detection solution

☐ Ultrasonic leak detector

☐ Fluorescent tracer dye

NOTE 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. (17.2.2)

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

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

17.2.5 A leak sealant shall not be introduced into the system.

17.2.6 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.

17.3 Evacuation

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

17.3.2 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.

17.3.3 The evacuation target shall be as indicated in the datasheet.

Evacuation Target Absolute Pressurerange

microns

10020025030050075010001500

17.3.4 The evacuation method shall be as indicated in the datasheet.

Evacuation Methodselect

Single evacuation to the target

Double evacuation with one dry-nitrogen break

Triple evacuation with two dry-nitrogen breaks

NOTE 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. (17.3.5)

17.3.6 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.

17.3.7 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.

17.3.8 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.

17.4 Standing Vacuum Decay Test

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

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

Standing Vacuum Decay Hold Durationrange

minutes

5101520304560120

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

Maximum Vacuum Rise Permitted During the Decay Holdrange

microns

501001502002505001000

NOTE 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. (17.4.4)

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

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

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

18 Charging

18.1 The charging method shall be as indicated in the datasheet.

Charging Methodselect

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

18.2 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.

18.3 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.

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

NOTE 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. (18.5)

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

18.7 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.

18.8 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.

19 Delivery, Storage, and Handling

19.1 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.

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

19.3 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.

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

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

19.6 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.

19.7 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.

20 Warranty

20.1 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.

Refrigerant Piping Warranty Periodrange

years

1235

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

20.3 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.

20.4 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.

20.5 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.

20.6 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.

21 Spare Parts

21.1 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.

Spare Parts to Be Furnishedcheckbox

☐ 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

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

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