11
The discharge pipework from the tundish:-
1. Shall fall continuously through its length.
2. Shall be of a heat resistant material, e.g. metal.
3. Shall not be fitted with any valves or taps.
4. Shall discharge to a safe visible position, e.g. onto the surface of an external wall or into a gulley.
5. Shall have a minimum of 300 mm straight pipework directly from the tundish.
Note: Where children may play or otherwise come into contact with discharges, a wire cage or similar guard must be
positioned to prevent contact whilst maintaining visibility.
Refer to Fig. 9 for suggested methods of terminating the discharge pipe safely.
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 the system is 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.
Alpha 500E - General Boiler Information
Fig. 9
TERMINATION INTO A HOPPER
At high level, discharge onto a roof is acceptable providing
the roof is capable of withstanding high temperatures and
there is a distance of 3 m from any plastic guttering systems
that would collect such discharge.
Note: The discharge will consist of scalding water and
steam. Asphalt, roofing felt and non-metallic rainwater
goods may be damaged by such discharges.
HIGH LEVEL TERMINATION
Tundish
D1
D2
300 mm
minimum
D1
D2
300 mm
minimum
Tundish
Type 'A' air gap
End of pipe to be
clearly visible
300 mm
minimum
Tundish
500 mm max.
from temp/press
relief valve
Metal discharge pipe (D2) from
tundish with continuous fall
Metal discharge pipe (D1)
from relief valve to tundish
Temperature/pressure
relief valve
300 mm
minimum
100 mm max.
70 mm min.
Gulley if
available
Pipe close to wall to
allow water to fan out
safely
Ground level
D2
D1
LOW LEVEL TERMINATION
To expansion
relief valve
