Technical data

10
600mm maximum
300mm
minimum
Safety device
(e.g. Temperature
relief valve)
Metal discharge pipe (D1) from
Temperature relief valve to tundish
Tundish
Discharge below
xed grating
(Building Regulation
G3 section 3.61 gives
alternative points
of discharge)
Fixed grating
Trapped
gully
Discharge pipe (D2 from tundish,
with continuous fall. See Building
Regulation G3 section 3.56,
Table 4 and worked example)
Valve outlet size Minimum size of
discharge pipe
D1
Minimum size of
discharge pipe
D2 from tundish
Maximum
re sista nce
allow e d,
expre sse d as a
length of straight
pipe (I.E . no
elbow s or bends)
Resista nce
created by each
elbow or bend
G1/2 15mm
22mm
28mm
35mm
up to 9m
up to 18m
up to 27m
0.8m
1.0m
1.4m
G3/4 22mm
28mm
35mm
42mm
up to 9m
up to 18m
up to 27m
1.0m
1.4m
1.7m
G1 28mm
35mm
42mm
54mm
up to 9m
up to 18m
up to 27m
1.4m
1.7m
2.3m
Fig 4 - Typical discharge
Table 4