Table 4: Sizing of copper discharge pipe “D2” for common temperature relief valve outlet sizes
4.4.2 Worked example
This example is for a G½ temperature
relief valve with a discharge pipe (D2)
(as fitted on 125 to 300L cylinders)
having 4 No. 22mm elbows and length
of 7m from the tundish to the point of
discharge.
From Table 4, the maximum resistance
allowed for a straight length of 22mm
copper discharge pipe
(D2) from a G½ temperature relief
valve is 9.0m. Subtract the resistance
for 4 No. 22mm elbows at 0.8m each
= 3.2m.
Therefore the maximum permitted
length
equates to 5.8m, which is less than the
actual length of 7m, therefore calculate
the next largest size.
Maximum resistance allowed for a
straight length of 28mm copper
discharge pipe (D2) from a G½
temperature relief valve is: 18m
Subtract the resistance for 4 No. 28mm
elbows at 1.0m each = 4m
Therefore the maximum permitted
length equates to 14m.
As the actual length is 7m, a 28mm
(D2) copper pipe will be satisfactory.
To Next Page
Loading...
