Technical information

600mm Max.
300mm
Min.
Temperature & pressure
relief valve
Metal discharge pipe (D1) from
temperature & pressure relief valve.
to tundish.
Metal discharge pipe (D2) from tundish
with continuous fall. See Table 2 and worked
example.
Tundish
Fixed grating
Trapped gulley
Discharge below
fixed grating.
(see page 10 for
alternative points
of discharge).

15
Valve outlet size Minimum size of
discharge pipe D1*
Minimum size of
discharge pipe D2*
from tundish
Maximum
resistance allowed,
expressed as a
length of pipe (i.e.
no elbow or bends)
Resistance created
by each elbow or
bend
G 1/2 15mm 22mm
28mm
35mm
Up to 9m
Up to 18m
Up to 27m
0.8m
1.0m
1.4m
G 3/4 22mm 28mm
35mm
42mm
Up to 9m
Up to 18m
Up to 27m
1.0m
1.4m
1.7m
G 1 28mm 35mm
42mm
54mm
Up to 9m
Up to 18m
Up to 27m
1.4m
1.7m
2.3m
&  Sizing of copper discharge pipe “D2” for common temperature valve outlet sizes.