Trane CVHH Installation, Operation And Maintenance Manual page 36

Vent Piping
Figure 23. Rupture disk vent pipe sizing (SI units); for use w ith
10
1
0
10
ASHRAE Standard 15
-15 5 2
7.4381x10 d (P
L =
2
fC
R
Note: This figure, provided as a r efer ence, is based on ASHRAE St andard 15. Vent line size is t ypically dict at ed by st at e or local code which m ay be different
from ASHRAE St andard 15 requirem ent s.
• L = equivalent length of discharge piping, m eters
• C = rated capacity as stam ped on the relief device in
r
SCFM (conversion: kg/s = SCFM * 0.0764 / 132.28)
C = C value from Table 8, p. 35
r
m in for IP; lb/m in = (kg/s) / 132.28)
• f = M oody friction factor in fully turbulent flow
• d = inside diam eter of pipe or tube, m m
• ln = natural logarithm
• P = absolute pressure at outlet of discharge piping,
2
kPa (atm ospheric pressure)
36
Pipe siz e a s a Fu n ct ion of "C" Va lu e a n d Le n gt h of Ru n
100
L = Pipe Le n gt h ( Equ iva le n t M e t e r s)
( M e t e r s x 3 .2 8 1 = Fe e t )
2
- P ) d * ln(P / P
0 2 0 2
-
500f
(convert C in kg/s to lb/
Table 8, p. 35
)
• P = allow ed back pressure (absolute) at the outlet of
0
pressure relief device, kPa
P = (0.15 P) + atm ospheric pressure
0
Pipe Siz e ( I .D .)
fr ict ion fa ct or
150 DN ( 6 NPS)
154 m m ( 6.06 in.)
f = 0.0149
125 DN ( 5 NPS)
128 m m ( 5.05 in.)
f = 0.0155
100 DN ( 4 NPS)
102 m m ( 4.03 in.)
f = 0.0163
80 DN ( 3 NPS)
78 m m ( 3.07 in.)
f = 0.0173
1000
CVHH-SVX001A-EN