This month’s query comes from a member in Ohio and concerns the seismic requirements in the International Building Code now being adopted by many states. In many cases, as in Ohio, seismic requirements are a new requirement. In this particular case the architect specified seismic restraints on the acoustical lay-in tile ceiling being installed in accordance with ASTM C636, Standard Practice for Installation of Metal Ceiling Suspension Systems for Acoustical Tile and Lay-In Panels. This is not good: ASTM C636 does not address seismic installation requirements. Bear in mind that some of the legacy codes did in fact contain details for specific items, including seismic restraints for many type of materials and installations. The International Building Code almost always references an industry standard (ASTM, AISI, etc.) and does not contain specific details.
Some resources available are two publications from the Ceilings & Interior Systems Construction Association: Guidelines for Seismic Restraint for Direct-hung Ceiling Assemblies (zones 3 and 4) and Recommendations for Direct-hung Acoustical Tile and Lay-In Panel Ceilings (zones 0–2). And the Northwest Wall and Ceiling Bureau has information on their Web site, www.nwcb.org, in the form of Field Technical Information document number 401 addressing seismic restraints for acoustical lay-in ceilings.
Also have a closer look at the interior cold-formed non-structural steel framing and get a copy of the referenced documents for your library to aid in putting together your estimate so there are no surprises downstream. And take a look at the amendments the IBC has adopted by the building code authority having jurisdiction in the areas where you conduct business to ascertain what if any seismic requirements apply—just to be on the safe side.
Another area of concern resulting in many questions has to do with fire-rated assemblies. There are several resources available for interior partitions and ceiling assemblies: UL, Warnock Hersey and the Gypsum Association. The assemblies are the results of tests performed on the actual materials specified in the assembly and usually conducted by the manufacturer of the prime material used. In some cases the materials are generic, but proprietary materials were used in other tests. Depending on how the local fire marshal interprets these tests, he or she might require the exact materials and not allow substitution. This recently came to light from an AWCI member who wanted to use screwed fasteners in lieu of wire ties for securing furring channels to the bottom of bar joists. While, on the surface, the use of screwed fasteners appears to provide a stronger connection, the rated assembly used wire ties in the test assembly. The only avenue of relief for the contractor was to approach the local fire marshal and request a variance on the rated assembly for use of a different method of securing the furring channel. In some cases, an Engineering Report conducted by one of the legacy codes is available to substantiate the use of different materials and methods in construction these assemblies.
It always amazes me the number of calls I get looking for a specific rating on a material. While a given material may have an Underwriters Laboratories Fire Classification, ratings are given only for assemblies, not individual materials.
Another area of concern is dealing with an old building. Some of the materials that were used then are no longer in production, and even if a rated assembly were available when the building was constructed, that may no longer be the case. A fire marshal may or may not accept an old and dated fire rating test, but it does no harm to ask.
For many years the Underwriters Laboratories Fire Directory consisted of a single volume; today it is three volumes consisting of four separate books. A search for a particular assembly requires a manual search for a specific rating containing specific materials and methods. Maybe in the future UL will provide a searchable database for fire-rated assemblies. In the meantime, if you are a member of the Steel Framing Alliance, you can go to their Web site and use a searchable database for fire-rated assemblies containing cold-formed steel framing members.
About the Author
Donald E. Smith, CCS, is AWCI’s director of technical services. Send your questions to him at email@example.com.