Kidde Fire Protection 400 Series, Design, Installation, Operation, And Maintenance Manual

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System Design
06-237518-001 3-19 July 2018
In hazards with a suspended ceiling, consideration shall be given to having nozzles in the
ceiling void performing a simultaneous discharge in order to equalize the pressure during
discharge. This reduces the risk of unnecessary damage to ceiling tiles and such. Nozzles in
ceiling voids can be installed upright directly from a tee or elbow from the branch pipe.
Also, nozzles in room voids shall be installed in such a way that the jets from the nozzles do
not damage the ceiling tiles during discharge (i.e. the nozzles shall be positioned vertically with
the discharge holes free of the ceiling tiles and/or escutcheon plates). For lightweight ceiling
tiles, it is a requirement to securely anchor all tiles within 1.5 m of each discharge nozzle.
In hazards with a raised floor (not gas tight) consideration shall be given for having nozzles
installed in the floor void to perform a simultaneously discharge in order to equalize the
pressure and achieve the extinguishing concentration below the floor.
In hazards such as server rooms, requirements to the release and equipment shut down
sequence may be needed as well as number of nozzles installed sufficient for providing the
design concentration between rows of server cabinets.
A range of nozzles, ½” to 1 ½”, with orifices from 3mm to 26mm can be provided. Nozzles
have a 180° or 360° discharge pattern. Nozzles can be installed pendant or upright.
3-17.1 Nozzle Coverage
In enclosures higher than 5m, nozzles may need to be positioned using a using a two tiered
nozzle arrangement. The nozzles can be mounted in the vertically up or pendant down position.
The maximum area coverage of the installed nozzle is 116 sq m (1250 sq ft). The maximum
area coverage of the installed nozzle will, however, be dependent on the required throughput
and actual nozzle pressure. The nozzle pressure is dependent on the design concentration and
the distribution pipe work layout. A maximum area coverage of 110m2 for a 1½" nozzle may
be achieved at a nozzle height of 2.2m and 60 bar as the nozzle pressure.
The 1½" nozzle fitted with the largest orifice operating at 60 bar pressure is capable of
protecting a volume of 243 m
3
(Class A) Therefore the area a nozzle can protect can be
calculated for each enclosure height using the following equation:
XY = 243/RoomHeight
Example: where RoomHeight is in metres, and XY is the product of the width and length of the
enclosure. Using the equation above, we can see, for example, that:
•
At a height of 3.0m, area coverage may be up to 81m
2
and a maximum nozzle spacing of
9.0m
• At a height of 4.0m, area coverage may be up to 60m
2
and a maximum nozzle spacing of
7.8m