Perforated Ceiling Tiles

By Brad Keyes…

Q: My facility is installing perforated ceiling tiles because it looks “modern” and does not look like the old healthcare setting. With the perforation in the ceiling tiles, does this mean I have to install sprinklers and fire alarm smoke detectors above and below the ceiling since the dropped ceiling is no longer a smoke-resistant barrier? I believe I have to also take the smoke compartment barrier walls to the deck… is that correct?

A: First of all, do you need smoke detectors in the area where the new ceiling tiles are being installed? If yes, then we need to address this issue, but the NFPA codes and standards do not require that many smoke detectors in a hospital. Unless you are employing Specialized Protective Measure locks (see section 19.2.2.2.5.2 of the 2012 Life Safety Code), or have specific requirements from a state or local authority that exceed what NFPA requires, smoke detectors are only mandatory in the following locations of a hospital:

  • In areas open to the corridor that are not directly supervised by a person (see section 19.3.6.1 of the 2012 LSC)
  • Near doors that are held open by devices that release on a fire alarm activation (see section 17.7.5.6.5.1 of NFPA 72-2010)
  • In elevator lobbies and elevator equipment rooms (see section 9.4.3.2 of the 2012 LSC)
  • In rooms where fire alarm panels (including NAC panels and off-premises monitoring transmission equipment) are located without direct supervision by a person (see section 9.6.1.8.1 of the 2012 LSC)

You may want to revisit why the smoke detectors are there in the first place. Check with your state and local authorities to see if they have requirements for smoke detectors to be there.

But assuming you do want to maintain the smoke detection level in this area where the new ceiling tiles are located, NFPA 72-2010 does address this issue. Let’s look at section 17.5.3.1.3 which discusses the requirements for an open grid ceiling. It says smoke detectors are not required below an open grid ceiling if the openings in the ceiling are ¼-inch or larger in the least dimension, and the openings constitute at least 70% of the surface area of the ceiling. So, what this means, smoke detectors are not required above the ceiling if the openings are less than ¼-inch and the accumulative area of the openings is 30% of the total surface area of the ceiling. But this section only applies if smoke detectors are required in the general area where these new ceiling tiles are being installed. But keep in mind, if you install smoke detectors where they are not required, they still must be installed in compliance with NFPA 72-2010.

Here are the requirements found in NFPA 13-2010, at section 8.15.13 for an approved open-grid ceiling. Open-grid ceiling must be installed below the sprinklers where all of the following apply:

  1. The openings of the open-grid ceiling must be at least ¼ inch or larger in the least dimension.
  2. The thickness or the depth of the material does not exceed the least dimension of the opening.
  3. The openings must constitute 70 percent of the area of the ceiling material.

If your ceiling tile openings are less than ¼-inch and the openings in the ceiling tile equal less than 70% of the ceiling area, then I conclude sprinklers would not be required above the ceiling.

There is one issue you need to be aware of… Most surveyors will cite you for having gaps in ceiling tiles greater than 1/8-inch as that would allow heat and smoke to filter up through the ceiling and would cause the sprinklers or smoke detectors to delay activation. Make sure these ceiling tiles do not have openings greater than 1/8-inch.

Smoke compartment barrier walls always have to extend from the floor to the deck above regardless whether or not the ceiling tiles have openings in them.

Gaps in Ceilings

Q: I am looking for the 1/8-inch gap reference for ceiling tiles. If the ceiling has broken tiles, or misaligned tiles, or gaps greater than 1/8-inch caused by anything (such as data cables temporarily run up through the ceiling), then I see that the surveyors will cite this. Is that actually written in the NFPA codes and standards anywhere? Is the 1/8-inch gap rule “real”? Does it use the 1/8-inch measurement anywhere? If so, where? If not, where does it come from?

A: No, there is no direct statement in the LSC that says gaps greater than 1/8-inch are prohibited, but ceilings containing smoke detectors and sprinklers must form a continuous membrane and any sizable gap in this membrane would allow smoke and heat to rise above the ceiling which would delay the activation of the detector or sprinkler, thereby causing an impairment.

Since the size of the gap must be quantifiable, and NFPA does not say how big the gap has to be before it is a problem, authorities having jurisdiction have ‘borrowed’ the 1/8-inch gap concept from NFPA 80 regarding the gap between a fire door and the frame. Authorities having jurisdiction are permitted to do this as section 4.6.1.1 of the 2012 Life Safety Code says the authority shall determine whether the provisions of the LSC are met. This means, when the Life Safety Code is not clear on a subject, the authorities have to make interpretations in order to determine compliance.

Strange Observations – Ceiling Penetrations

Continuing in a series of strange things that I have seen while consulting at hospitals…

This picture was taken in an electrical room. Where the conduits extend upwards and penetrate the suspended ceiling, the gaps around the conduits are too large.

Most surveyors will use the NFPA 80 maximum 1/8-inch gap rule fire door clearance to frames as a standard for the maximum gap around conduit penetrations, where the ceiling is required to act as a membrane for smoke detectors or sprinkler heads.

In situations like this, the easiest and best solution is to remove the suspended ceiling from the electrical room, and relocate the lights in the ceiling to the deck above.