Water versus gas-based data center fire suppression

Don't let a water-only fire suppression system in your data center leave you all wet. Experts say a combined approach of sprinklers and gas is needed to keep your servers safe.

No one believes it could happen to them -- a fire in the data center. But all it takes is a malfunctioning power supply or an improperly maintained AC unit and your job and your data center is literally up in smoke.

Belts disintegrate, components burn out, and the only thing between you and disaster is your fire suppression system.

At the recent Data Center Decisions conference in New York, panelists and attendees weighed in on the best methods for fire suppression in the data center -- sprinklers versus clean agent, a fire suppressing gas. The consensus was equally mixed -- both approaches had pros and cons.

But follow-up discussions with fire suppression experts determined one method is not enough to keep your facility safe and equipment functioning. You need both.

Bob Opkins, senior safety representative at JM Family Enterprises Inc., is responsible for data center fire suppression at the Deerfield Beach, Fla.-based automotive services company. He uses clean agent with sprinklers as a backup.

"The dry system acts a lot quicker than water. It's activated by smoke," Opkins said. "The sprinklers are activated by heat. It kicks on when the dry system doesn't work."

It's obvious, IT pros don't want water on their equipment. But Opkins said about seven years ago, experts determined that if you cleaned up the water right away, the equipment would be fine. But most people wouldn't want to take the chance.

Bob Burkland, president of Orion, Mich.-based Healey Fire Protection Inc., agreed. Sprinklers save foundations and outer walls, but not contents.

"That's a false sense of security when a data center manager looks up and sees only sprinklers. When those go off, you've got a whole lot of problems," Burkland said. "If you've ever seen a sprinkler discharge that has been installed for a while, it's not clean water. It's sewer water."

So what are your options for fire suppression in the data center?

Water-based sprinklers

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. Preaction is an approach that combines dry-pipe water suppression with smoke detection.

According to fire suppression expert Lance Harry, business development manager at Clifton, N.J.-based Kidde Fenwal Protection Systems, the upshot of water-based systems is familiarity.

"Local authorities are very familiar with those systems, and it's easier for local inspectors or fire marshals to sign off on them," Harry said. "People understand that water is a good fire suppressant. It's a known element."

Also, cost is an issue, since it's generally the least expensive option.

What's the downside? Water and servers don't mix. Though there are products available to shield the cabinets from water.

But Harry warned, "If you have a fire in a cabinet, you wouldn't want to shield it."

Waterless agents

Halon, a chemical suppressant, popular in the 1970s and 1980s, was banned in 1987 as an ozone depleting substance.

Today, Halon systems are grandfathered in. You couldn't buy a new Halon system, but existing systems are legal in the U.S., and they can be recharged, although it is getting harder. Many manufacturers are no longer supporting Halon systems and the cost of maintaining and recharging Halon systems is getting harder to predict, according to Harry.

"I would recommend replacing a Halon system today, or start budgeting for it," Harry said. "You don't want to replace a $100,000 system. But what if you have a discharge and can't recharge it? Then you have to replace [the Halon system]. You want to be able to do it on your own terms."

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Today, the most common waterless agent used is a gas called FM200.

The major pro of FM200 is that it's safe. People can be in the room when it goes off and it's totally benign to electronic equipment, according to Harry. Also, nothing can get inside and around components like a gas.

The downside to FM200 is cost. It's more expensive than a sprinkler system and a little more expensive than Halon. Also, it doesn't have a totally clean environmental profile. While FM200 does not deplete the ozone, it is a greenhouse gas producer that contributes to global warming.

Regardless of the system, data center managers need to have some kind of plan in place, and should test discharge sequences, batteries, pull testing and the rest of the system, according to National Fire Protection Association code and the local fire department.

According to Burkland, the loss history in the data center space is very good, meaning the risk of fire is fairly low. But many fires aren't reported and that can lead to a false sense of security.

"What is your downtime worth?" Burkland asked. "What's going to happen to you if you're down a minute, an hour or a week?"

Let us know what you think about the story; e-mail: Matt Stansberry, News Editor

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