Worked Example - Samsung RC090MHXEA Installation Manual

Installation
Examples of acceptable discharge arrangements are:
1. Ideally below the fixed grating and above the water seal in trapped gulley.
2. Downward discharges at a low level: i.e. up to 100mm above the external surfaces such as car parks, hard standings,
grassed area etc are acceptable providing that where children play or otherwise come into contact with discharges, a
wire cage or similar guard is positioned to prevent contact whilst maintaining visibility.
3. Discharges at a high level; e.g. in to metal hopper and metal down pipe with the end of the discharge pipe clearly visible
(tundish visible or not) or onto a roof capable of withstanding high temperature discharges of water and 3m from any
plastic guttering systems that would collect such discharges (tundish available).
4. Where a single pipe serves a number of discharges, such as in blocks of flats, the number served should be limited to
not more than 6 systems so that any installation can be traced reasonably easily. The single common discharge pipe to
be connected. If unvented hot water storage systems are installed where discharges from safety devices may not be
apparent i.e. in dwellings occupied by blind, infirm or disabled people, consideration should be given to the installation
of an electronically operated device to warn when discharge takes place.

Worked Example

The example below is for G1/2 temperature relief valve with a discharge pipe (D2) having 4 elbows and length of 7m from
the tundish to the point of discharge.
From Table 1: Maximum resistance allowed for a straight length of 22mm copper discharge pipe (D2) from a G1/2
temperature relief valve is: 9m subtract the resistance for 4 x 22mm elbows at 0.8m each = 3.2m.
Therefore the maximum permitted length equates to: 5.8m.
5.8m is less than the actual length of 7m therefore calculate the next largest size.
Maximum resistance allowed for a straight length of 28mm pipe (D2) from a G1/2 temperature relief valve equates to: 14m.
As the actual length is 7m, a 28mm (D2) copper pipe will be satisfactory.
Table 1: Sizing of copper discharge pipe 'D2' for a temperature relief valve with a G1/2 outlet size (as supplied)
Size of discharge pipework
22mm
28mm
35mm
54
EHS mono_RC＊＊＊MHXGA_IM_E_34411A(3).indd 54
Maximum length of straight pipe
(no bends or elbows)
Up to 9m
Up to 18m
Up to 27m
Deduct the fi gure below from the
maximum length for each bend or elbow
in the discharge pipe
0.8mm
1mm
1.4mm
2012-11-26 오후 3:02:06