2. Downward discharges at a low level: i.e. up to 100mm above external
surfaces such as car parks, hard standings, grassed areas etc. are
acceptable providing that where children may 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 high level: e.g. into 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 system that would collect such discharges
(tundish visible).
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 should be at least one pipe size larger than the largest
individual discharge pipe to be connected. If unvented hot water storage
systems are installed where discharges from safety devices may not be
apparent e.g. 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.
Note:
The discharge will consist of scalding water and steam. Asphalt, roofing
felt and non-metallic rainwater goods may be damaged by such discharges.
Typical discharge pipe arrangement
Safety device
(e.g. temperature relief valve)
500mm maximum
Tundish
300mm
minimum
Metal discharge pipe (D1) from
temperature relief valve to tundish
Discharge below
fixed grating (3.9d
gives alternative
points of discharge)
Fixed grating
Trapped gulley
Metal discharge pipe (D2) from tundish,
with continuous fall. See 3.9d i-iv.
Table 1 and worked example
8
Zip Varipoint III Installation, Maintenance and User Instructions - August 2008
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