User Manual

A white paper issued by Siemens  September 2015

Why should I protect my data center with an extinguishing system?

There is no question about the need for an gas extinguishing system to protect your valuable

assets: The biggest risk is always the risk of fire. Siemens recommends installing an inert gas ex-

tinguishing system to protect your data center against the risk of fire.

Will solid-state drives solve the problem?

When alternative technologies like solid-state drives replace today’s technologies, the problem of

disruptions to HDDs caused by discharge noise may disappear on its own. However, because our

tests showed variances in the sensitivity of the HDDs tested, Siemens recommends contacting the

manufacturer to check the technology or to obtain additional information.

Is background noise in your data center already disturbing the HDDs?

Strong ventilation and air-conditioning flow rates make data centers, and especially the cabinets

where HDDs are located, a very noisy environment. The background noise level typically reaches

80 to 85dB(A). HDDs are designed to operate in this noisy environment at full performance. A

discharge noise of about 100dB(A) is 15 to 20dB above the background noise (30 to 100 times the

noise energy) which means that the ordinary background noise is a minor factor.

What is the correlation between room size and sound level?

The mass flow needed for a certain protection volume and the sound energy density increase

linearly with the room volume. This means that the noise level is independent of the protection

volume and is instead primarily a function of nozzle acoustics, room acoustics, discharge time and

mass flow. The flow direction may be an additional optimization measure, but it only has a local

effect.

Is it better to use one large nozzle rather than several small ones?

As mentioned above, the noise level generated is primarily dependent on the mass flow. This

means that one nozzle with an orifice of a particular diameter generates the same noise level as

two nozzles with orifices of half that diameter.

Careful placement of the nozzles in relation to the room layout should determine the selection of

the nozzle size and orifice.

Can the Sinorix Silent Nozzle be used in rooms with false floors or ceilings?

False floors and ceilings are typically not acoustically separated from the room. The small version

of Sinorix Silent Nozzle (SDN(S)-S) has a dedicated drilling pattern to limit the gas flow to the

horizontal plane, and is therefore especially appropriate for false floors or ceilings.