System Design
April 2020 3-2 06-237619-001
• For server rooms, consider the duration of the discharge delay from first alarm until all hard
discs have properly parked the head before Agent release to prevent head crashing. Con-
sider the location of nozzle in relations to servers using turning hard discs.
• Determine if total flooding or dedicated protection is the appropriate solution for this hazard
or series of hazards.
• Measure the shape of enclosure or room.
• Take into consideration the layout and type of equipment installed or to be installed in the
protected enclosure/room. Will this impact nozzle placement, add to the fire hazard, or cre-
ate a need for less agent as the volume of the room is reduced.
• Calculate the net volume of enclosure or room.
• Take into consideration any suspended ceiling or elevated floor voids. Determine any im-
pact this will have on the location of discharge nozzles.
• Are there provision for automatically closing doors upon fire detection? Should these be
added? Can the windows be replaced with fixed shut type or would this create its own haz-
ard? If the latter, can there be provisions for automatically closing the windows upon fire
detection?
• Ensure that pressure relief vents to atmosphere or to a room having sufficient volume to
accommodate the increase in pressure. The flow calculation software output includes the
required pressure venting area.
• Take special consideration for pressure relief venting of enclosures or rooms which have
large glass areas (windows) or weak building parts.
• Plan escape routes.
• Plan access routes for moving cylinder to the final installed location.
• Select fire detectors according to the type of fire anticipated (response time).
• Plan what audible and visual alarms are needed for the site and hazard.
Note: In order to avoid excessive pressure, appropriate pressure relief vents shall always be
provided. These should open when pressure builds up at the beginning of the discharge,
and close as soon as the pressure inside/outside has equalized.
After achieving the minimum design concentration, the extinguishing concentration shall be
maintained within the enclosure until the fire department or trained firefighting personnel can
take over (hold time).
Anticipated minimum hold time required is typically 10 minutes. However, local fire brigades
may have a longer traveling time and the Authorities Having Jurisdiction may therefore require
a longer hold time.
CAUTION
Pressure relief vents must conform to the following:
• Pressure relief vents should always vent out to atmosphere.
• Pressure relief vents should not vent out into fire escape routes.
• If “cascade” venting through another room (other than the protected room)
to atmosphere, then the intermediate room should be of a low fire risk.
To Next Page
Loading...
