YQA Fuel Piping Systems in Buildings
17.01 What are common types of piping in buildings?
Fuel piping inside buildings is typically carbon steel piping. Regulations prohibit pipe materials such as plastics that would have a relatively low failure temperature in the event of a fire.
Schedule 40 carbon steel black pipe is typical for primary piping. Schedule 10 carbon steel black pipe is typically used for secondary piping.
Double wall piping in buildings is sometimes provided as pre-engineered piping such as that made by Perma-Pipe and Rovanco. Many mechanical contractor also shop fabricate their own secondary containment systems.
17.02 Should pipe in buildings be threaded or welded?
Aboveground piping may be threaded or welded. We highly recommend welded pipe joints for aboveground piping to minimize the risk of leaks. Either butt weld or socket weld fittings are appropriate.
There are locations where welded joints are not practical and threaded joints are allowed: connection to tanks and equipment, connections to existing fuel system piping, and connection to threaded valves and accessories.
Threaded pipe fittings are commonly malleable iron – not cast iron, and are typically Class 150 or Class 300 rated. Many contractors use forged fittings for unions, because of their superior sealing characteristics, or replace unions with flange connections.
17.03 Is secondary containment required for piping in building?
Aboveground piping is often required to be double contained by State and local regulations – however, requirements vary widely. NFPA 30 requirements for piping allow for single wall piping, however, piping within walls or otherwise inaccessible needs to have welded pipe joints.
In practice, most technical building have double wall piping within buildings for all piping that can contain fuel. Vent piping is typically single wall.
An alternative for piping inside buildings is single wall piping within floor trences designed for fluid containment. This piping arrangement is often used in generator rooms to simplify pipe routing, and to allow for gravity return flow from day tanks.
17.04 Is fire protection required for pipe in buildings and how is it provided?
Local regulations may require fire protection for fuel piping in buildings where it is routed outside special rooms such as generator rooms, boiler rooms, and tank storage rooms. Typically 2 hour fire protection is required.
A typical method of providing the fire protection is by insulating the pipe with fire rated insulation.
A common alternative method is to route the piping through fire rated shafts which are often provided for utility risers in multi-story building.
Either method prevents visual inspection of the piping, so double contained pipe with leak detection is typically used.
17.05 What are requirements for fire-stops for pipe in building?
Where fuel piping passes through building walls the fire rating of the wall must be maintained by using approved fire-stop sealant around the pipe penetration.
17.06 What are emergency valves and where should they be located?
Emergency valves are installed in fuel piping to provide shutoff in the case of a fire event. The most common type of emergency valve is a normally closed valve, held open by a fusible link which fails at 165 degrees F.
Emergency shutoff valves are located immediately inside the wall of a building or room, so that a fire in the room will close and isolate the valve. In some installations an emergency valve is located at each generator, to protect against a fire related failure of the fuel hoses at the generator.
Many common emergency valves are not UL or FM approved. Common brands of approved valves are Jamesbury and Essex. These valves include valves that are fire rated, and a fail-safe close mechanism, held open but a fusible link.