Removal of Lubricating Oil from Ammonia Refrigerating Systems
Proposed Rules: Closed to Comments
Statement of Basis and Purpose of Proposed Rule
The Fire Code regulates the manufacturing, storage, handling, use and transportation of hazardous materials in New York City. This includes ammonia, a corrosive liquid.
Ammonia in its pure (anhydrous) form (100% concentration) is used as a refrigerant in a limited number of applications, typically large industrial refrigerating systems. In New York City, 120 to 420 gallons of ammonia circulate under pressure in each ammonia refrigerating system. By way of comparison, common household bleach has a concentration of only 5 to 10 percent ammonia.
The accidental release of such highly concentrated ammonia from such refrigerating systems can pose a public safety threat. Exposure to ammonia can result in severe skin burns and eye damage and, if inhaled, can cause severe lung injury and asphyxiation. Ammonia also has flammable properties. A spark can ignite concentrated ammonia vapors.
The risk of release from ammonia refrigerating systems and other closed systems is generally low. Modern equipment includes various safeguards to prevent accidental refrigerant release. However, recent events in Brooklyn’s Prospect Park have revealed a vulnerability in ammonia refrigerating systems when lubricating oil must be manually removed.
Lubricating oil is used in ammonia refrigerating systems to ensure the proper operation of their mechanical components. Spent lubricating oil collects at various locations in the system and must be removed. Some ammonia refrigerating systems are equipped with automatic removal systems that separate the spent lubricating oil from the ammonia refrigerant and remove it from the system. Such automatic separation and removal prevents accidental refrigerant release.
In other refrigerating systems, the spent lubricating oil is not separated from the refrigerant and must be manually removed from the refrigerant system, in some systems through a simple valve. If the valve is not immediately shut after the spent lubricating oil is removed, ammonia refrigerant is released. If there is a problem shutting the valve, the ammonia refrigerant will continue to be released and in a short time endanger the maintenance or servicing personnel. Such a release occurred in connection with the maintenance of the ammonia refrigerating system serving Prospect Park’s ice skating rink. Fortunately, it occurred when the ice rink was not open to the public and the park was lightly occupied so there were no injuries, but a strong odor of ammonia was detected at a considerable distance from the facility.
A simple remedy, which has been adopted by the latest industry standard, can prevent this scenario: installing two valves in sequence, one self-closing. Personnel performing manual removal of the lubricating oil must continuously hold open the self-closing valve by squeezing the valve. As soon as the self-closing valve is released, it shuts and prevents any further release of lubricating oil or ammonia refrigerant. The main valve can then be closed in a calm, controlled manner.
To address the risk of refrigerant release from ammonia refrigerating systems, the Fire Department proposes a new rule, 3 RCNY 606-01, which would establish requirements and procedures for the removal of lubricating oil from such systems.
Specifically, the proposed rule would require:
· regular servicing for ammonia refrigerating systems that automatically remove the lubricating oil;
· basic safety procedures for ammonia refrigerating systems that require manual removal of lubricating oil and are equipped with dual valves, one self-closing;
· additional safeguards for removal of lubricating oil from ammonia refrigerating systems equipped with a simple valve, including:
o a second Fire Department-certificated person to monitor the removal (the Fire Department encourages the presence of a second person in all oil removal operations);
o conducting the oil removal process outside of regular business hours; and
o notifying the Fire Department; and
· recordkeeping, including documenting the periodic servicing of ammonia refrigerating systems and all removals of lubricating oil from such systems.
The proposed rule is underlined, indicating that it is an entirely new rule.
“Shall” and “must” denote mandatory requirements and may be used interchangeably in the rules of this department, unless otherwise specified or unless the context clearly indicates otherwise.
Guidance with respect to the interpretation of the Fire Code and Fire Department rules may be obtained using the Public Inquiry Form on the Fire Department’s website,http://www1.nyc.gov/site/fdny/about/resources/code-and-rules/nyc-fire-code.page.