Installation Guide
51
Inches (“) Water Column (w.c.) Method of stating pressure measured in inches of water
column by a manometer or pressure gauge. Commonly used in the gas industry when the
pressure is less than one (1) PSI.
¼ PSI = 7 in. w.c. ½ PSI = 14 in. w.c. 1 PSI = 28 in. w.c.
2 PSI = 56 in. w.c. 5 PSI = 139 in. w.c.
Joint A connection between two lengths of tubing or a length of tubing and tting.
Listed Equipment or materials including a list published by an organization acceptable to
the authority having jurisdiction and concerned with product evaluation that maintains peri-
odic inspection of production of listed equipment or materials and whose listing states either
that the equipment or material meets appropriate standards or has been tested and found
suitable for use in a specied manner.
Load The amount of gas in CFH required by an appliance, or group of appliances, per their
rating plate.
Lockup Pressure, Regulator The system pressure, immediately downstream of the regula-
tor, at which the regulator valve will completely close (leak tight) under no-ow conditions to
prevent the downstream pressure from exceeding a predetermined level.
LP Gas Liqueed petroleum. Fuel gas that is stored and transported in a liquid state, i.e.,
propane, butane, and mixtures of these and other heavier hydrocarbons.
MBTU 1,000 BTUs. See BTU above.
Manifold (Header) A pipe or tting to which a number of branch lines are connected.
Meter An instrument installed to measure the volume of gas delivered through a piping
system.
NFPA National Fire Protection Agency
OD Outside Diameter of pipe or tubing.
Piping As used in this document, either pipe or tubing, or both. Pipe is a rigid conduit of
iron, steel, copper, brass or aluminum, while tubing is a semi-rigid conduit of corrugated
stainless steel.
Piping System As used in this manual, an assembly of corrugated stainless steel tubing and
tubing ttings, intended for eld assembly, and installed in residential or commercial build-
ing to distribute fuel gas to gas utilization equipment within the building. The piping system
may also include a gas pressure regulators, shuto valves, tube shielding devices, distribution
manifolds and other approved devices or components.
Pressure Unless otherwise stated, is expressed in pounds per square inch (PSI) above atmo-
spheric pressure (i.e. gauge pressure).
Pressure Drop The loss in static pressure of gas due to friction or obstruction in tubing,
valves, ttings, regulators and burners.
PSIG Pounds per square inch gauge. The pressure, as read from a measurement gage or
device. Gauge pressure is pressure above atmospheric pressure and is sometimes referred
to as PSI.
Purge To displace the original air, or gas, or a mixture of gas and air in a gas conduit with a
new air/gas mixture.
Qualied Installer A qualied installer must meet applicable qualications set forth by the
state and/or local administrative authorities which enforce the plumbing, mechanical, electri-
cal and/or building codes at the locale where the gas piping is to be installed. The installer
must also be certied in the use of the HOME-FLEX® gas piping system.
Regulator A device that reduces and controls pressure. It automatically opens and closes in
response to changing pressure conditions in the downstream piping.