Samsung RC090MHXEA Installation Manual page 54

Discharge Arrangement
P & T Relief
22 mm metal pipe with continuous fall up
to 9m equivalent length (D2).
• The discharge will consist of scalding waterand steam. Asphalt, roofing felt and non-metallic rainwater goods
may be damaged by such discharges. It is not acceptable to discharge straight into a soil pipe.
NOTE
The relief valve should be installed to discharge in accordance with G3 of the Approved Document of the Building
Regulations and should be piped to where it is visible, but will not cause danger to persons or damage to materials.
The following information is taken from Approved Document G3 of the Building Regulations and is provided to assist with
the design and installation of the discharge pipework. However, the information is not exhaustive and reference should
always be made to Approved Document G3 of the Building Regulations. The final decision regarding any arrangements rests
with Building Control and it is recommended that their advice is sought if you have any concerns regarding this aspect of the
installation.
The tundish should be vertical, located in the same space as the unvented hot water storage system and be fitted as close as
possible and within 500mm of the safety device e.g. the temperature relief valve. The discharge pipe (D2) from the tundish
should terminate in a safe place where there is no risk to persons in the vicinity of the discharge, be of metal and:
a Be at least one pipe size larger than the nominal outlet size of the safety devices unless its total equivalent hydraulic
resistance exceeds that of a straight pipe 9m long i.e. discharge pipes between 9m and 18m equivalent resistance
length should be at least two sizes larger than the nominal outlet size of the safety device, between 18 and 27m at least
3 sizes larger, and so on. Bends must be taken into account in calculating the flow resistance. Refer to table 1.7 and the
worked example below. An alternative approach for sizing discharge pipes would be to follow BS6700 Specification for
design and installation, testing and maintenance of services supplying water for domestic use within buildings and their
curtilages.
b Have a vertical section of pipe at least 300mm long, below the tundish before any elbows or bends in the pipework.
c Be installed with a continuous fall.
d It is preferable for the discharge to be visible at both the tundish and the final point of discharge but where this is not
possible or practically difficult there should be clear visibility at one or other of these locations.
EHS mono_RC＊＊＊MHXGA_IM_E_34411A(3).indd 53
Typical Discharge Pipe Arrangement
15 mm discharge pipe
600 mm max.
Valve
300 mm min.
Dotted line showing alternative route
with single tundish being used
Discharge below fixed grating
Fixed Grating
Trapped gully
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2012-11-26 오후 3:02:06