Gas Pipe Sizing - Introduction - Page 1 2 3 4 
Gas
Properties
The Table below lists some of
the more useful properties in building services for natural gas and liquid
petroleum gas (LPG).
|
Properties |
Natural Gas |
Liquid Petroleum Gas (LPG) Propane |
|
Composition & Chemical symbol |
92.6% Methane CH4 3.6% Ethane
C2H6 0.8% Propane C3H8 0.2% Butane C4H10 |
100% C3H8 |
|
Gross Calorific Value (GCV) (MJ/m3)(kJ/litre) |
41.6 |
95 as gas |
|
Gross Calorific Value (GCV) (MJ/litre) |
0.0416 |
25.5 as liquid |
|
Gross Calorific Value (GCV) (MJ/kg) |
53.3 |
50 |
|
Net Calorific Value (NCV) (MJ/m3) |
38.7 |
86 |
|
Density of gas at 15oC (kg/m3) |
0.78 |
1.85 |
|
Density of liquid under pressure (kg/litre) or (kg/m3) |
- |
0.512 kg/litre or 512 kg/m3 |
|
Ignition temperature (oC) |
650 |
510 |
|
Operating pressure (millibars) |
20 |
37 |
|
Volume of gas per volume of liquid (m3/m3) or (m3/litre) |
- |
274 m3gas /m3 liquid or 0.274 m3 gas / litre liquid |
|
Volume of gas per kg mass of liquid (m3/kg) |
- |
0.54 |
LPG (Gas) Pipe Sizing
Notes
Allowable pressure drops
Medium pressure lines - 450 Pa per m run ( 2 P.S.I. per 100 foot )
Low pressure lines - 4.1 Pa per m run ( ½” w.g. /100 ft)
- Maximum
1300 Pa total pressure drop in any run.
Gas Pressures
First stage regulation at tank pressure is reduced from 6 bar to 0.7 bar.
Second stage regulation at building pressure is reduced to 50 mbar
(0.05 bar)
At equipment and appliances - 37 millibar
(0.037 bar)
Natural Gas
Pipe Sizing
Allowable pressure drops
The allowable pressure drop between the outlet of the meter and
appliances must not exceed 1 mbar or 0.001 bar
or 100
Pressure loss is generally
limited to between 75 Pa and 125 Pa from the meter to the point of use.
Gas Pressures
At equipment and appliances - 20 millibar
(0.020 bar)
Gas Pipe Sizing - Introduction - Page 1 2 3 4