Apr 11 2012

Radiant Ceiling Fire Dampers

Category: BlogBKeyes @ 5:00 am

I recently received a message from an old friend in regards to the testing requirements for ceiling mounted fire dampers. It was his contention that the ceiling was just a simple acoustical tile and grid suspended ceiling and by itself was not 2-hour fire rated and therefore the ceiling mounted fire dampers were not required, nor did they have to be tested.

What he actually had was radiant ceiling fire dampers mounted in the supply and return HVAC diffusers in the ceiling. These devices are part of an UL listed floor/ceiling assembly such as G-235 or G-227, which brought back lots of bad memories for me.

The hospital were I spent most of my development career years had an addition they wanted to have built in the early 1970′s, and the succesful contractor offered millions $$$ in savings to the hospital if they could install a UL listed (approved by building codes and state regulations) G-235 floor/ceiling assembly, rather than the heavy-duty poured concrete beams and floors and decks that were specified. The hospital leaders at the time could only see $$$ saved in construction costs, and approved the bid.

The floor/ceiling assembly consists of unprotected steel bar-joists supporting a poured light-weight concrete floor that is thinner and has less psi density than a regular 2-hour fire rated concrete floor. The UL standard G-235 makes up the fire rating by having a special suspended ceiling consisting of a particular acoustical tile and grid system, complete with radiant fire dampers mounted inside the HVAC supply and return (or exhaust) diffusers, and all openings in the ceiling grid (such as light fixtures, PA speakers, etc.) had to be tented with a special insulating materials that resembled mineral wool. And, all the lay-in ceiling tiles had to be clipped.

It wasn’t long after the addition was opened for business that the hospital maintenance staff was either poorly trained or poorly supervised, but within 15 years or so, many of the special requirements of UL G-235 (such as the radiant ceiling fire dampers, the tenting and the special ceiling tiles) were removed and replaced with hospital standard materials, that did not comply with the UL listing. And most of the tiles were never re-clipped after lifting them out of the grid. Enter the state survey agency for HCFA (that’s CMS before it was called CMS) and they found all of the problems that 15 years of neglect created. The hospital wanted to restore the ceiling to UL G-235 standards, but soon found that UL withdrew the listing on G-235 and the state survey agency made the hospital adhere to UL G-227 which was similar, but more difficult.