N.Y.C. Admin. Code § MC 1107: Section MC 1107: Refrigerant Piping

1107.1 General.

The design of refrigerant piping shall be in accordance with ASME B31.5. Refrigerant piping shall be installed, tested and placed in operation in accordance with this chapter.

1107.1.1 Protection of refrigerant piping located inside buildings.

All refrigerant piping and fittings installed at a height less than 7 feet 3 inches (2209.8 mm) above the floor shall be concealed or otherwise protected from mechanical damage except at the point of connection to terminal equipment.

1107.2 Piping location.

Refrigerant piping that crosses an open space that affords passageway in any building shall be not less than 7 feet 3 inches (2209.8 mm) above the floor unless the piping is located against the ceiling of such space. Refrigerant piping shall not be placed in any elevator, dumbwaiter or other shaft containing a moving object or in any shaft that has openings to living quarters or to means of egress. Refrigerant piping shall not be installed in an enclosed public stairway, stairway landing or an exit.

1107.2.1 Piping in public corridors.

Refrigerant piping shall not be installed in public corridors.

Exception: Refrigerant piping in public corridors that complies with either of the following conditions:

1. Piping containing Group A1 refrigerant may be located in public corridors provided that the complete discharge of any one refrigerant system into the public corridor will not result in a refrigerant density equal to or greater than 50 percent of the allowable density set forth in Table 1103.1; and

1.1. There is not more than one refrigerant system's piping per tenant; and

1.2. Refrigerant piping and fittings are concealed or otherwise protected from mechanical damage; and either

1.3. Refrigerant piping and fittings are installed with brazed joints; or

1.4. The refrigerant equipment manufacturer provided pre-charged tubing systems installed in accordance with the refrigerant equipment manufacturer's instructions;

2. Piping containing Group A1 refrigerant may be located in public corridors provided that the complete discharge of any one refrigerant system into the public corridor will not result in a refrigerant density of 100 percent of the allowable refrigerant density set forth in Table 1103.1; and

2.1. Such system is provided with fast-acting shutoff valves on both high and low pressure refrigerant line sets, actuated by either local refrigerant monitors in the corridor, or on sensing a drop in pressure on either high or low pressure refrigerant line sets; and

2.2. Upon accidental discharge, actuation of installed refrigerant shutoff valves shall initiate locally installed alarm; and

2.3. Installation of fast-acting shutoff valves, refrigerant detectors, and alarms shall be in accordance with Appendix C; and

2.4. There is not more than one refrigerant system's piping per tenant; and

2.5. Refrigerant piping and fittings are concealed or otherwise protected from mechanical damage; and either

2.6. Refrigerant piping and fittings are installed with brazed joints; or

2.7. The refrigerant equipment manufacturer provided pre-charged tubing systems installed in accordance with the refrigerant equipment manufacturer's instructions.

1107.2.2 Piping in concrete floors.

Refrigerant piping installed in concrete floors shall be encased in pipe ducts. The piping shall be isolated and supported to prevent damaging vibration, stress and corrosion.

1107.2.3 Refrigerant piping penetrations.

Refrigerant piping shall not penetrate floors, ceilings or roofs.

Exceptions:

1. Penetrations connecting the basement and the first floor.

2. Penetrations connecting the top floor and a machinery penthouse or roof installation.

3. Penetrations connecting adjacent floors served by the refrigeration system.

4. Penetrations by piping in a direct system where the refrigerant quantity does not exceed Table 1103.1 for the smallest occupied space through which the piping passes.

5. Penetrations by piping in a direct system complying with Section 1107.2.3.1.

6. In other than industrial occupancies and where the refrigerant quantity exceeds Table 1103.1 for the smallest space, penetrations for piping that connects separate pieces of equipment that are either:

6.1. Enclosed by an approved gas-tight, fire- resistive duct or shaft with openings to those floors served by the refrigeration system or

6.2. Located on the exterior of the building where vented to the outdoors or to the space served by the system and not used as an air shaft, closed court or similar space.

1107.2.3.1 Direct systems.

Piping containing a quantity of Group A1 refrigerants in excess of Table 1103.1 for the smallest occupied space through which the piping passes, shall comply with Section 1107.9.

1107.3 Pipe enclosures.

Rigid or flexible metal enclosures or pipe ducts shall be provided for soft, annealed copper tubing used for refrigerant piping erected on the premises and containing other than Group A1 refrigerant. Enclosures shall not be required for connections between condensing units and the nearest riser box(es), provided such connections do not exceed 6 feet (1828.8 mm) in length.

1107.4 Condensation.

Refrigerating piping and fittings, brine piping and fittings that, during normal operation, will reach a surface temperature below the dew point of the surrounding air, and are located in spaces or areas where condensation will cause a safety hazard to the building occupants, structure, electrical equipment or any other equipment or appliances, shall be protected in an approved manner to prevent such damage.

1107.5 Materials for refrigerant pipe and tubing.

Piping materials shall be as set forth in Sections 1107.5.1 through 1107.5.7.

1107.5.1 Steel pipe.

Carbon steel pipe with a wall thickness not less than Schedule 80 shall be used for Group A2, A3, B2 or B3 refrigerant liquid lines for sizes 1.5 inches (38.1 mm) and smaller. Carbon steel pipe with a wall thickness not less than Schedule 40 shall be used for Group A1 or B 1 refrigerant liquid lines 6 inches (152.4 mm) and smaller, Group A2, A3, B2 or B3 refrigerant liquid lines sizes 2 inches (50.8 mm) through 6 inches (152.4 mm) and all refrigerant suction and discharge lines 6 inches (152.4 mm) and smaller. Type F steel pipe shall not be used for refrigerant lines having an operating temperature less than -20°F (-28.9°C).

1107.5.2 Copper and brass pipe.

Standard iron-pipe size, copper and red brass (not less than 80-percent copper) pipe shall conform to ASTM B 42 and ASTM B 43.

1107.5.3 Copper tube.

Copper tube used for refrigerant piping erected on the premises shall be seamless copper tube of Type ACR (hard or annealed) complying with ASTM B 280. Where approved, copper tube for refrigerant piping erected on the premises shall be seamless copper tube of Type K or L (drawn or annealed) in accordance with ASTM B 88. Annealed temper copper tube shall not be used in sizes larger than a 2-inch (50.8 mm) nominal size. Mechanical joints shall not be used on annealed temper copper tube in sizes larger than 7/8-inch (22.2 mm) OD size.

1107.5.4 Copper tubing joints.

Copper tubing joints used in refrigerating systems containing Group A2, A3, B1, B2 or B3 refrigerants shall be brazed. Soldered joints shall not be used in such refrigerating systems. Brazed joints shall be made in accordance with ASME Boiler and Pressure Vessel Code, Section IX Welding and Brazing Qualifications or in accordance with American Welding Society AWS B2.2 Standard for Brazing Procedure and Performance Qualification.

1107.5.5 Soldered joints.

Soldered joints shall be made as follows: soldered joint surfaces shall be cleaned, a flux conforming to ASTM B 813 shall be applied, and the joint shall be soldered with a solder conforming to ASTM B 32.

1107.5.6 Aluminum tube.

Type 3003-0 aluminum tubing with high-pressure fittings shall not be used with methyl chloride and other refrigerants known to deteriorate aluminum.

1107.5.7 Insulation.

Pipe and other refrigerant-containing components' insulation shall meet the requirements of Section 1204.1 of this code.

1107.6 Joints and refrigerant-containing parts in air ducts.

Joints and all refrigerant-containing parts of a refrigerating system located in an air duct of an air-conditioning system carrying conditioned air to and from human-occupied space shall be constructed to withstand, without leakage, a pressure of 150 percent of the higher of the design pressure or pressure relief device setting.

1107.7 Exposure of refrigerant pipe joints.

Refrigerant pipe joints erected on the premises shall be exposed for visual inspection prior to being covered or enclosed.

1107.8 Stop valves.

Systems containing more than 6.6 pounds (3 kg) of a refrigerant in systems using positive-displacement compressors shall have stop valves installed as follows:

1. At the inlet of each compressor, compressor unit or condensing unit.

2. At the discharge outlet of each compressor, compressor unit or condensing unit and of each liquid receiver.

Exceptions:

1. Systems that have a refrigerant pumpout function capable of storing the entire refrigerant charge in a receiver or heat exchanger.

2. Systems that are equipped with provisions for pumpout of the refrigerant using either portable or permanently installed recovery equipment.

3. Self-contained systems.

1107.8.1 Liquid receivers.

Systems containing 100 pounds (45.4 kg) or more of a refrigerant, other than systems utilizing nonpositive displacement compressors, shall have stop valves, in addition to those required by Section 1107.8, on each inlet of each liquid receiver. Stop valves shall not be required on the inlet of a receiver in a condensing unit, nor on the inlet of a receiver which is an integral part of the condenser.

1107.8.2 Copper tubing.

Stop valves used with soft annealed copper tubing or hard-drawn copper tubing 7/8-inch (22.2 mm) OD standard size or smaller shall be securely mounted, independent of tubing fastenings or supports.

1107.8.3 Identification.

Stop valves shall be identified where their intended purpose is not obvious. Numbers shall not be used to label the valves, unless a key to the numbers is located near the valves.

1107.9 Alternative refrigerant piping safety.

Where refrigerant piping penetrates floors, ceilings, or roofs pursuant to Section 1107.2.3, it shall comply with the alternative safety requirements of Sections 1107.9.1 through 1107.9.5.

1107.9.1 Nongas tight enclosures.

Where refrigerant piping and fittings pass through public corridors or occupied spaces in shafts or cavities that are not gas tight, such piping and fittings shall comply with the requirements of EN378 Part 1, Section 3.2.3.

1107.9.2 Occupied spaces.

Refrigerant piping systems in occupied spaces shall comply with the requirements of EN378 Part 1, Section C.3.2.1.

1107.9.2.1 Space volume calculations.

Space volume calculations shall comply with EN378 Part 1, Section 7.

1107.9.2.2 Dilution transfer openings.

Where required, dilution transfer openings shall be provided in accordance with EN378 Part 3, Section 6.3.2.

1107.9.3 Refrigerant shutoff valves.

Where required, refrigerant shutoff valves shall comply with the requirements of EN378 Part 3, Sections 6.4.1 through 6.4.3.

1107.9.4 Refrigerant safety alarms.

Where required, refrigerant safety alarms shall comply with the requirements of EN378 Part 3, Sections 8.1 through 8.2.

1107.9.5 Refrigerant detectors.

Where required, refrigerant detectors shall comply with the requirements of EN378 Part 3, Section 9.3.1.