New York City Gas Work Qualification Exam

A leak check is performed to verify the system does not leak and is intended to discover open outlets, defective appliance connections and defects developed since initial installation (normally performed after pressure testing), while a pressure test verifies the gas-tight integrity of piping following installation or modification.

Threaded piping is permitted up to 4 inches (102 mm) only at a pressure no greater than 1/2 psig, while piping over 1/2 psig through 5 psig that is 4 inches or larger must be welded and all piping operating above 5 psig must be welded (manufactured and listed gas trains supplied with the appliance may be threaded).

Piping operating up to 1/2 psig is tested with a nonmercury gauge at 3 psig for a minimum of 30 minutes, while piping over 1/2 psig through 5 psig is tested at 50 psig for a minimum of 30 minutes (over 5 psig through 15 psig is 100 psig for 1 hour).

Outdoor purging provisions apply where design operating gas pressure is greater than 2 psig or the piping meets Table 406.7.1.1 size/length criteria and purging with fuel gas is stopped at 90-percent fuel gas by volume on a combustible gas indicator, while systems at 2 psig or less not meeting those criteria may be purged indoors or outdoors and purging stops when fuel gas is detected by a listed combustible gas detector.

At the 3 psig magnitude the analog gauge must be calibrated in increments not greater than one-tenth of a pound (and have a face not smaller than 2¼ inches with a minimum 270-degree dial arc), while at the 5 psig magnitude increments of one-fifth of a pound apply and a 2¼-inch diameter gauge range shall not exceed 10 psig.

'Labeled' means equipment bears an attached identifying mark of the manufacturer stating the manufacturer's name, function and performance characteristics, and the name/identification of an approved agency indicating a representative sample was tested and evaluated; 'listed' refers to material identified in a published list maintained by an approved agency.

An approved testing agency is approved by the department as qualified to test and evaluate the performance of materials regulated in their use by the code, while an approved inspection agency is approved to perform inspections required by the code; 'approved agency' is the broader parent term.

The department issues a certificate of compliance for fuel-gas-burning equipment, heating systems and boilers upon satisfactory inspection of service equipment and satisfaction of sign-off requirements, while a certificate of approval of gas installation is the separate document that must be filed with the utility company before it may lawfully supply gas where new meters (other than replacements) are required.

Final inspection of gas piping systems must be performed by the department in the presence of the permit holder, registered design professional of record, or superintendent of construction, whereas final inspection of other work not requiring a certificate of occupancy may, at the owner's option, be performed by an approved agency.

For natural gas systems the point of delivery is the outlet of the service meter assembly (separating upstream service piping from the installed system), while the piping system is all fuel piping, valves and fittings from the outlet of the point of delivery to the outlets of the appliance shutoff valves.

The Plumbing Code regulates nonflammable medical gas, inhalation anesthetic, vacuum piping, nonmedical oxygen systems and sanitary/condensate vacuum collection systems, while fuel-gas distribution piping and equipment, fuel gas-fired water heaters and water heater venting systems are regulated by the Fuel Gas Code.

A flame safeguard automatically shuts off fuel to a main burner or group of burners when the means of ignition becomes inoperative and when flame failure occurs, whereas a limit control responds to changes in pressure, temperature or level, a manual reset valve is an automatic shutoff valve set to close on unsafe conditions that must be reopened by hand, and automatic ignition refers to ignition of gas at the burner when the gas controlling device is turned on.

The diagrammatic floor plan shows the location, layout and spacing of plumbing fixtures, summation of plumbing loads, and size, location and material of building sewers/drains and soil, waste, vent, water and gas distribution piping, while riser diagrams cover story heights, stacks and risers.