Installation Guide

44
Chapter 8: Denitions
A.G.A. American Gas Association
ANSI Z223.1 1988 The 1988 edition of the National Fuel Gas Code published by American
National Standard Institute. Also known as NFPA 54 (National Fire Protection Association).
Appliance (Equipment)
Any device which utilizes natural gas or propane as a fuel or raw
material to produce light, heat, power, refrigeration or air conditioning.
Approved
Acceptable to the authorities having jurisdiction.
Authority Having Jurisdiction The organization, oce or individual responsible for
"approving" equipment, an installation or a procedure.
BTU
Abbreviation for British Thermal Unit, which is the quantity of heat required to raise the
temperature of one pound of water one degree Fahrenheit .
CFH
Gas ow rate stated in cubic feet per hour.
Design Pressure The maximum operating pressure permitted by this document, as deter-
mined by the design procedures applicable to the materials involved.
Drip Leg
The container (dirt trap pocket) placed at a low point in a system of piping to col-
lect and remove foreign material or condensation.
EHD (Eective Hydraulic Diameter)
A relative measure of ow capacity used to compare
individual sizes between dierent manufacturers. The higher the EHD number the greater
ow capacity of the piping.
Full Lockup
The capability of totally stopping the ow of gas if the load goes to zero, thus
preventing the downstream pressure from increasing more than a certain upper limit pres-
sure above the set point.
ID
Inside diameter of pipe or tubing.
Inches (") 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.
1 PSI = 28 in. w.c. ½ PSI = 14 in. W.C. ¼ PSI = 7 in. w.c.
Load The amount of gas in CFH required by an appliance, or group of appliances, per their
rating plate.
LP Gas
Liqueed 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.
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.
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.