When a data center fire at The Planet took down 700,000 websites most people were pretty shocked. After all, how could something as simple as a fire be so disruptive. Surely these places have fire protection systems, right?

In fact data center fire protection is a difficult business and requires a whole lot of specialist knowledge and investment. One of the reasons it is so hard is that water and servers just don’t mix. There are products to shield cabinets from water but if you have a fire inside a cabinet you really don’t want to shield it.

So, if water in a data processing environment is a bad thing, what’s the solution?

Detection

The first line of defence is a super advanced fire detection system. Server racks are fitted with temperature sensors, rooms are fitted with heat and smoke detectors tied to an early warning system. Getting fire detection right is hugely important as a false alarm can be costly.

Usually detection is cross-zoned using both photoelectric and ionization type spot detectors. This zoning offers protection against false alarms and accidental discharges of the suppression system, by requiring one of each type of detector to be in alarm, prior to the initiation of a discharge.

Supression

There are two types of fire suppression systems - water based and gas based. In general data centers are required to use both systems as fire regulations insist on water based sprinklers being used to protect the buildings.

There are two kinds of water-based systems, wet pipe and dry pipe. Wet pipe has water in the pipes at all times, while dry pipe only has water in the system when the valve is released making it much less likely to leak over the servers.

Halon gas based systems were popular in the 60’s and 70’s but the chemical is harmful to the ozone layer and no systems have been installed since 1987. However existing Halon systems are still legal in the US.

In 2008 the most common waterless agent used in data center fire suppression is a gas called FM200.

The advantage of FM200 is that it’s safe. Technicians can be in the room when it goes off and it’s totally benign to electronic equipment.

The major downsides to FM200 are cost and the fact it isn’t totally friendly to the environment.

Prevention is better than cure

Figuring out the most likely causes of fire and preventing them is a much cheaper option than installing equipment to put out fires after they start. The main causes are electrical faults in old equipment and, amazingly, accidental ignition from discarded cigarettes.

Dave Admirand, chief data center engineer at PTS Data Center Solutions, says in his own experience, electrical fires are the most common types of fires in data centers. He says, “These are typically caused by electronic equipment failures or failures of the branch circuits powering the data center equipment, including UPS and air-conditioning equipment - if located in the data center.”

Joe Ziemba, marketing manager of engineered systems for ANSUL,
says another primary cause of fires is wastebaskets.

“Despite the emergence of nonsmoking facilities globally, apparently there are still some examples of fires caused by accidental ignition,”

Even factors such as the design of the data center are taken into account. Most modern locations are build to extremely high standards but this wasn’t always the case. According to Mark Lillycrop, CEO at Arcati, a company that analyzes data centers, managers should trace potential problems back to the original data center design.

“It’s important that steel is used instead of wood where possible and that no flammable substances are used or stored within the machine room area. This may seem obvious for purpose-built data centers, but if existing buildings are converted into data centers, it can be a significant issue.”

Just because your data center is secured against fires it doesn’t mean the surrounding rooms are. Protecting the entire building is also extremely important.

Backup Systems

The fire at The Planet (caused by a faulty transformer) was made much worse when fire officials refused to allow technicians to start up the backup generator in case this caused further problems. This meant that even though the hosting of 700,000 websites could have continued with minimal interruptions - it didn’t.

Ideally a data center should have the ability to switch seamlessly to an off-site system so that when one site is destroyed or forced to shut down another can start up within minutes.

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This entry was posted on Thursday, July 3rd, 2008 at 12:33 pm and is filed under Fires. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.