General Information
06-237619-001 1-15 April 2020
1-6 NOISE CONSIDERATION
Hard disc drives may fail during release of Kidde IGS due to acoustic noise issues. At specific
frequencies and decibel (dB) levels, vibrations transfer through the flexible stainless steel
cover of a hard drive case transmitting vibration into the inner workings of the drive, causing
the read/write element to misalign and fail. The combination of audible warning alarms and
nozzle sound are currently believed to be the most important factor that may cause hard discs
to “vibrate” and fail. Typical sound level from an Inert gas nozzle is approx. 120 – 130 db
measured in a distance of 6.6 feet (2 meters).
Note: Warning alarms are typically 110 – 120 db or must be a minimum of 10 db above the
ambient sound level during normal operation processes.
To the best of Kidde Fire Systems’s knowledge, the reported failures happened during testing
or from unexpected releases where no fires were involved. As such, normal server shutdown
was not initiated and discharge delays did not operate, thus not permitting sufficient time for
the discs to stop spinning. Therefore, it is important to ensure proper shutdown of computer
systems prior to discharge if possible. Additionally, when testing systems, it is advisable to
initiate a shutdown prior to the test.
Other precautionary measures may also be taken such as housing the drives within sound
proof cabinets or the use of solid state drives. For further information consult your drive
manufacturer and/or Kidde Fire Systems.
1-7 SYSTEM DETECTION AND CONTROL
Detection, actuation, and control systems shall be installed, tested, and maintained in
accordance with the requirements of the authority having jurisdiction, and are not covered
under the scope of this manual.
Automatic detection, alarm and actuation (release) is preferred, provided as a dual stage
detection alarm control system. Selection of detection devices shall involve due consideration
of the involved flammables, the environment, and the response time anticipated.
Means for manual release of the system shall be provided unless not allowed by the AHJ.
Manual releases must be located, installed, or suitably protected so that they are not subject
to mechanical, chemical or other damage that would render them inoperative.
The control equipment shall supervise the actuating and monitoring devices and the associated
wiring and shall indicate / warn of failure of any supervised device.
Alarms or indicators (or both) shall be installed in the protected enclosures to indicate the
operation of the system, first stage alarm, and second stage release alarm. The type (audible,
visual, or olfactory), their quantity, and location shall be such that their purpose is satisfactorily
accomplished.
Audible and visual pre-discharge alarms shall be provided within the protected area to give
positive warning of impending discharge. The operation shall be continued after discharge until
positive action has been taken to acknowledge the alarm and proceed with appropriate action.
A discharge delay between pre-alarm and discharge, sufficient to allow personnel to evacuate
prior to discharge shall, where required, be provided. For hazard areas subject to fast growth
fires, where the provision of a discharge delay would seriously increase the threat to life and
property, a discharge delay may be omitted if agreed by all relevant parties.
Discharge delays shall be used only to safeguard personnel evacuation or to prepare the hazard
area for discharge (by closing of doors or vents, shutting down equipment etc).
Inhibit switches shall be provided for protected enclosures where the concentration after a
release will be hazardous to personnel. Inhibition of a system release will not be possible;
inhibit switches to only be activated between first and second alarm (release).
Care shall always be taken to thoroughly evaluate and correct any factors that could result in
unintended system activation / release.
The release unit used for the Kidde IGS shall be listed with the fire alarm and suppression
control panel.
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