FSL Low Noise Nozzle quiets more than rumour...

On 12th September 2016, BBC News released an article in which the ING Bank in Romania suffered unexpected damages to its computer servers during a fire drill, which saw the discharge of a gas-based fire suppression system. This has caused an increase in concerns to some regarding noise level generated from inert gas suppression systems as it was reported that the servers were damaged due to the high noise levels generated by the high pressure release of the system.

Some background information on this subject in data centres;

  • Standard fire alarm sounders generate 90dB
  • Although not specified by the disc drive manufacturers the sensitivity range is apparently 500Hz to 10kHz.
  • Not all drives are equally sensitive
  • Some drives may experience reduced performance above 110dB (only during the fire event)
  • Some drives may be temporarily out of order 120d 9only during the fire event)
  • Some drives are not affected by sound levels above 130dB
  • The report on this item does not state the manufacturer of the disc drives

The system in question was subject to a peak pressure actuation where the initial system pressure is much higher during the early stages of discharge.

The FSL Inertech system uses a controlled discharge to alleviate these issues and reduce the discharge rate by 50% over a peak pressure system.

Other alternative measures FSL use are;

• The smallest nozzles possible to minimise the flow rate

• The lowest flow rate possible; this can be achieved using a 120 sec discharge time

• Position the nozzles as far from the disc drives as possible

• Use the Inertech low noise nozzle

• Encourage the use of hard drives less susceptible to vibration and noise; such as solid state drives

Standard Inertech nozzle testing was measured in a 110m3 steel enclosure, providing the worst case scenario as the sound reverberates from the walls, ceiling and floor to multiply the sound level. From tests we would expect our standard nozzles to produce 126dB at 2m (with a 60 second discharge time) in the metal enclosure and be significantly less than in an open data centre filled with racks/cabinets. Considering these circumstance we would expect the sound to be attenuated.

Should the client wish to reduce the sound level further, under the same conditions we would expect the sound level to be 119dB at 2m for a 120 second discharge in a steel enclosure. The 120 second discharge time is permitted in the NFPA 2001 and ISO14520 and is included in the draft of EN15004 to be published next year.

We are pleased to announce the FSL low noise nozzle.

Designed to provide peace of mind to you and your customer, the FSL Low Noise Nozzles are designed to discharge the Inert gases in a uniform configuration and reduce air turbulence and noise in the enclosure to less than 110dB. The low noise nozzles are available in either a ½” (NF351515) or 1” (NF352515) size.

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