Buildings Bulletin 2017-001 clarifies the required testing extent for alterations to fuel gas piping systems that is already in existence, these alterations may be done to a single branch alone or may affect the whole system. The New York City Fuel Gas code shall also remain in effect and the document does not override NYC Fuel Gas Code requirements and the changes noted herein are effective immediately and are applicable for existing buildings with gas piping systems installed lawfully and has a distribution pressures of 1/2 psig.
The NYC FGC (Fuel Gas Code) denotes that inspections and testing should be completed successfully before allowing the system to come into service and provisions of section FGC 406.1 states that the gas piping system should be tested as a complete unit and should a branch be added to it, a complete unit test should be done regardless if the previous existing system has already been tested. Although a complete unit test need not be the entire system if the affected portions where the new branch was placed can be isolated from the unaffected portion of the pipelines. Any addition, alteration or repair of the system entails testing of the affected piping to ensure safety.
Multi-tenant building require separate shutoff valves for each tenant space. Any alteration or repair to the system of a single tenant space and downstream to the shutoff valve may only require isolated testing on the affected tenant space but for buildings without individual shutoff valves, then a more extensive test is required.
Specifics
For some terms as used in the bulletin, it shall be understood that they will carry the same definition as is used in the New York City FGC. It should also be noted that a Branch is defined as a section the gas piping system going down from a riser and leads to an appliance or equipment. As indicated in Sec. FGC 404.5, no less than 2 elbow swings are required in order to take a branch off a riser.
The NYC FGC makes use of the term isolated and its variations to denote a portion of the gas piping system that is separated by a double block with 2 valves installed in a series with an intermediate bleed valve. A test unit may also be isolated by disconnecting the new/altered pipes from the existing and putting in a temporary coupling and cap. Also, a single valve cannot be used to isolate a test unit regardless of its pressure rating. After a successful test of the new pipes, isolation fittings shall be removed and the new piping will be connected to the existing system and this new connection is subject to leak checks following guidelines set by Sec. FGC 406.6.3
Aside from the testing noted herewith, owner's may be required further testing and/or additional requirements of the gas utility which needs to be fulfilled before having the gas system to be fully functional.