2 PVC (polyvinyl chloride)
PE (polyethylene)
CPE (chlorinated polyethylene)
IIR (isobutylene-isoprene rubber)
EPDM (ethylene-propylene diene
monomer)
4 Inflatable gasholder, approx. 2.5 m³,
3-fold protection against rupture
6/8/9 - poor, o satisfactory,
10/13 + good, ++ very good
7 Short-term/continuous load
11 Permeability coefficient, P,
for new material
12 HF = high-frequency seam
welding
HW = hot-wedge seam welding
HA = hot-air seam welding
C = cementing
HV = hot vulcanizing
FF = fusion firing
HT = heat-solvent tape sealing
5.4.5 Gas pipe, valves and fittings
Gas pipe
The following types of gas pipes are in use:
- PVC pipes with adhesive joints
- steel pipes (water supply pipes) with screw couplings
- plastic hoses.
Galvanized steel water supply pipes are used most frequently, because the entire piping system
(gas pipe, valves and fittings) can be made of universally applicable English/U.S. Customary
system components, i.e. with all dimensions in inches. Pipes with nominal dimensions of 1/2" or
3/4" are adequate for small-to-midsize plants of simple design and pipe lengths of less than 30 m.
For larger plants, longer gas pipes or low system pressure, a detailed pressure-loss (pipe-sizing)
calculation must be performed (cf. chapter 10.2).
Table 5.13: Gas-pipe pressure losses (Source: OEKOTOP)
Volum
flow, Q
(m³ /h
0.1
0.2
0.4
0.6
0.8
1.0
1.5
2.0
v1
m/s
0.35
0.71
1.4
2.1
2.8
3.5
5.3
7.0
1/2“
dp/l2
cmWG/10m
0.03
0.12
0.47
1.06
1.9
2.9
6.7
11.8
Pipe (galv. steel pipe)
¾”
v1 dp/l2
m/s cmWG/10m
0.16 0.004
0.32 0.02
0.64 0.06
0.94 0.15
1.3 0.27
1.6 0.41
2.3 0.85
3.2 1.6
v1
m/s
0.09
0.18
0.36
0.53
0.72
0.88
1.33
1.8
1”
dp/l2
cm WG/10 m
0.001
0.004
0.016
0.034
0.06
0.09
0.2
0.4
1 Velocity of flow in the pipe
2 Differential pressure (pipe only) stated in cm WG per 10 m pipe
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