California Green Building Code (CALGreen) – Supermarket refrigerant leak reduction

The ozone layer depletion is caused by the greenhouse gases which mainly constitutes of the refrigerant used in the units. These need to be regulated by strict Environmental Protection Agency. Those refrigerants that are harmful for ozone layer depletion are being completely phased out. Only the refrigerants having low-global warming potential (GWP) with value less than 150 are allowed to be used.

CALGreen Code Section 5.508.2: Supermarket refrigerant leak reduction. 

New commercial refrigeration systems shall comply with the provisions of this section when installed in retail food stores 8,000 square feet or more conditioned area, and that utilize either refrigerated display cases, or walk-in coolers or freezers connected to remote compressor units or condensing units. The leak reduction measures apply to refrigeration systems containing high-global-warming potential (high-GWP) refrigerants with a GWP of 150 or greater. New refrigeration systems include both new facilities and replacement of existing refrigeration systems in existing facilities.

Exception: Refrigeration systems containing low-global warming potential (low-GWP) refrigerant with a GWP value less than 150 are not subject to this section. Low-GWP refrigerants are non-ozone-depleting refrigerants that include ammonia, carbon dioxide (CO2), and potentially other refrigerants.

CALGreen Code Section 5.508.2.1: Refrigerant piping. 

Piping compliant with the California Mechanical Code shall be installed to be accessible for leak protection and repairs. Piping runs using threaded pipe, copper tubing with an outside diameter (OD) less than 1/4 inch, flared tubing connections and short radius elbows shall not be used in refrigerant systems except as noted below.

CALGreen Code Section 5.508.2.1.1: Threaded pipe. 

Threaded connections are permitted at the compressor rack.

CALGreen Code Section 5.508.2.1.2: Copper pipe. 

Copper tubing with an OD less than 1/4 inch may be used in systems with a refrigerant charge of 5 pounds or less.

CALGreen Code Section 5.508.2.1.2.1: Anchorage. 

One-fourth-inch (1/4) OD tubing shall be securely clamped to a rigid base to keep vibration levels below 8 mils.

CALGreen Code Section 5.508.2.1.3: Flared tubing connections. 

Double-flared tubing connections may be used for pressure controls, valve pilot lines and oil.

Exception: Single-flared tubing connections may be used with a multi-ring seal 

coated with industrial sealant suitable for use with refrigerants and tightened in accordance with manufacturer’s recommendations.

CALGreen Code Section 5.508.2.1.4: Elbows. 

Short radius elbows are only permitted where space limitations prohibit use of long radius elbows.

CALGreen Code Section 5.508.2.2: Valves. 

Valves and fittings shall comply with the California Mechanical Code and as follows.

CALGreen Code Section 5.508.2.2.1: Pressure relief valves. 

For vessels containing high GWP refrigerant, a rupture disc shall be installed between the outlet of the vessel and the inlet of the pressure relief valve.

CALGreen Code Section 5.508.2.2.1.1: Pressure detection. 

A pressure gauge, pressure transducer or other device shall be installed in the space between the rupture disc and the relief valve inlet to indicate a disc rupture or discharge of the relief valve.

CALGreen Code Section 5.508.2.2.2: Access valves. 

Only Schrader access valves with a brass or steel body are permitted for use.

CALGreen Code Section 5.508.2.2.2.1: Valve caps. 

For systems with a refrigerant charge of 5 pounds or more, valve caps shall be brass or steel and not plastic.

CALGreen Code Section 5.508.2.2.2.2: Seal caps. 

If designed for it, the cap shall have a neoprene O-ring in place.

CALGreen Code Section 5.508.2.2.2.2.1: Chain tethers. 

Chain tethers to fit over the stem are required for valves designed to have seal caps.

Exception: Valves with seal caps that are not removed from the valve during stem operation.

CALGreen Code Section 5.508.2.3: Refrigerated service cases. 

Refrigerated service cases holding food products containing vinegar and salt shall have evaporator coils of corrosion-resistant material, such as stainless steel; or be coated to prevent corrosion from these substances.

CALGreen Code Section 5.508.2.3.1: Coil coating. 

Consideration shall be given to the heat transfer efficiency of coil coating to maximize energy efficiency.

CALGreen Code Section 5.508.2.4: Refrigerant receivers. 

Refrigerant receivers with capacities greater than 200 pounds shall be fitted with a device that indicates the level of refrigerant in the receiver.

CALGreen Code Section 5.508.2.5: Pressure testing. 

The system shall be pressure tested during installation prior to evacuation and charging.

CALGreen Code Section 5.508.2.5.1: Minimum pressure. 

The system shall be charged with regulated dry nitrogen and appropriate tracer gas to bring system pressure up to 300 psig minimum.

CALGreen Code Section 5.508.2.5.2: Leaks. 

Check the system for leaks, repair any leaks, and retest for pressure using the same gauge.

CALGreen Code Section 5.508.2.5.3: Allowable pressure change. 

The system shall stand, unaltered, for 24 hours with no more than a +/- one pound pressure change from 300 psig, measured with the same gauge.

CALGreen Code Section 5.508.2.6: Evacuation. 

The system shall be evacuated after pressure testing and prior to charging.

CALGreen Code Section 5.508.2.6.1: First vacuum. 

Pull a system down at least 1000 microns (=/- 50 microns), and hold for 30 minutes.

CALGreen Code Section 5.508.2.6.2: Second vacuum. 

Pull a second system vacuum to a minimum of 500 microns and hold for 30 minutes.

CALGreen Code Section 5.508.2.6.3: Third vacuum. 

Pull a third vacuum down to a minimum of 300 microns, and hold for 24 hours with a maximum drift of 100 microns over a 24-hour period.

Intent:

This requirement will assist in meeting statewide requirements for the reduction of greenhouse gas emissions to 1990 levels and to prevent ozone depletion. Currently the refrigerants are regulated at the federal level by the Environmental Protection Agency, and those containing ozone-depleting chemicals are being gradually phased out. In California, the Global Warming Solutions Act of 2006, Assembly Bill 32 (Chapter 488, Statutes of 2006), calls for the reduction of greenhouse gas emissions to 1990 levels by the year 2020. Although these damaging compounds have been widely outlawed for most uses, prior to CALGreen, these issues were not addressed by the Title 24 building standards.

Compliance Method:

Determine if the code section applies. If so, clearly note in the construction documents and specifications that the required leak reduction measures have been incorporated.

Note: The replacement of existing refrigeration systems in existing facilities must comply with this code requirement.

Enforcement:

Plan intake: The plan reviewer should confirm if this code section applies by verifying that the project is a new retail food store with 8,000 square feet or more of conditioned area and utilizes either refrigerated display cases or walk-in coolers or freezers connected to remote compressor units or condensing units.

Note: If the existing system is going to be replaced with a new refrigeration system, then this code system section applies.

On-site enforcement: The inspector should verify within the construction documents that equipment installed complies. Inspection of this equipment may be combined with verification of building commissioning or testing and adjusting.

(Excerpted from ‘Guide to the 2019 California Green Building Standards Code Nonresidential’ – Chapter 5)