New guidance for cloud ceiling fire protection

Under certain conditions, a sprinkler system isn’t needed on both the cloud ceiling and the structural ceiling, a new study finds
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Wednesday, August 28, 2013

QUINCY, Mass.—Cloud ceilings—drop ceilings that don’t extend all the way to perimeter walls—are increasingly popular in commercial and industrial buildings. But for fire protection, is a sprinkler system necessary on both the cloud ceiling and the structural ceiling above it?

That’s the question asked by a newly completed Fire Protection Research Foundation study. The foundation, an affiliate of the National Fire Protection Association, based here, initiated the project. Hughes Associates, a fire protection consulting firm based in Baltimore, conducted the research.

Amanda Kimball, research manager for the foundation, told Security Systems News that the findings of the study, which focused on large, contiguous cloud ceilings, now give “guidance on when you can omit sprinklers from a structural ceiling above a cloud ceiling,” based on such factors as ceiling height and the gap size of the cloud ceiling.

Jason Floyd, a senior engineer at Hughes Associates involved in the study, told SSN that it will benefit end users because they can “avoid the cost of having two sprinkler systems.” But the study also benefits installers and others, he said, because “there will now be some kind of formal guidance available for system designers and system installers on how to design your system for these types of ceilings. Right now, the code is pretty much silent on cloud ceilings.”

NFPA 13, Standard for the Installation of Sprinkler Systems, “does not have definitive guidance on automatic sprinkler installation requirements for these ceilings and in some conditions requires sprinklers at both the structural ceiling and cloud ceiling panel elevations,” according to the NFPA website.

The site also said that “recent NFPA 13 change proposals were rejected based on a lack of validation of modeling results.”

That’s where the foundation came in—to do research that could provide guidance for possible revisions of the code, Kimball said. “There were just a lot of questions on what do you do with these cloud ceiling, so that’s why it came to us,” she said.

Cloud ceilings are growing in popularity, she and Floyd said.

“You see them a lot now in retail spaces and restaurants, even in office buildings,” Floyd said. “It’s just sort of different aesthetic, something more than just the usual drop ceiling above your head.”

Kimball said that the down economy has led commercial businesses to reuse existing spaces instead of having new ones built. When reusing a building, cloud ceilings can be useful to hide heating and cooling ductwork or improve acoustics.

But in the event of a fire, Kimball said, such a ceiling “allows smoke to travel up above that cloud ceiling.” Smoke going above the sprinklers located on the cloud ceiling could cause a delay in the activation of those sprinklers, which is why NFPA 13 currently requires sprinklers on the structural ceiling as well.

So, Floyd said, the research project looked at the question of: “Is there a gap size between clouds where the amount of energy from the fire that goes up through the gap to the structural ceiling is small enough that you still can activate the sprinkler on the cloud in sufficient time to control the fire?”

The answer was “yes,” he said. “What the study determined was that there is a gap size and it’s a function of the height of the clouds above the floor, and as long as your gap is smaller than that then you wouldn’t need sprinklers on the structural ceiling, you could just have sprinklers in the clouds, provided that both the structural ceiling and the clouds were non-combustible.”

The results of the study may lead to changes in NFPA 13, of which a new version will be issued in 2016, Kimball said.

Floyd said, “The hope is now that this study gets picked up by NFPA 13 and then it gets pulled into the code either as new code language or perhaps explanatory material in the back.”

He said that in the meantime, the report is available on the NFPA’s website for installers and others to read. “So you could use it as a basis to ask your local authority having jurisdiction for an exception to the code. So if you’re building a building that met these requirements, you might get your local fire marshal or whoever is doing design review to accept the design without the additional sprinklers based on the results of this report. There’s almost always that discretion,” he said.