Heatrae Sadia PremierPlus Installation And User Manual page 17

Valve Minimum Size Of
Outlet Size Discharge Pipe D1
G1/2 15mm
G3/4 22mm
G1 28mm
Table 5: Sizing of copper discharge pipe (D2) for common temperature relief valve outlet sizes
Safety device
(e.g. Temperature
relief valve)
600mm maximum
Discharge pipe (D2) from tundish,
with continuous fall. See Building
Regulation G3 section 3.56,
Table 5 and worked example
Figure 10: Typical discharge pipe arrangement (extract from Building Regulation G3 Guidance Section 3.50)
Minimum Size Of
Discharge Pipe D2 From
Tundish
22mm
28mm
35mm
28mm
35mm
42mm
35mm
42mm
54mm
Metal discharge pipe (D1) from
Temperature relief valve to tundish
Tundish
300mm
minimum
Maximum Resistance
Allowed, Expressed As A
Length Of Straight Pipe (I.E.
No Elbows Or Bends)
up to 9m
up to 18m
up to 27m
up to 9m
up to 18m
up to 27m
up to 9m
up to 18m
up to 27m
Discharge below
(Building Regulation
G3 section 3.61 gives
alternative points
Resistance Created
By Each Elbow Or
Bend
0.8m
1.0m
1.4m
1.0m
1.4m
1.7m
1.4m
1.7m
2.3m
fixed grating
of discharge)
Fixed grating
Trapped
gully
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