The seismic categories correspond to the seismic zones referenced by the old building code.

"The vague language of the IBC regarding the requirements for acoustical ceiling installation has presented special challenges to architects, ceiling contractors and building officials," said Mark Fowler, architectural consultant for NWCB.

"NWCB saw an urgent need to provide its members and the larger construction and architectural community and municipalities with an easy-to-read document clarifying the intent of the code," he said.

Fowler collaborated with member contractors, manufacturers, suppliers and building officials to create this document, which is considered the first definite source addressing the requirements of the new code for acoustical ceilings.

"The use of the new NWCB standards outlined in the document will bring uniformity to construction drawings and inspection of suspended ceilings," Fowler said.

The Washington Association of Building Officials supports the document and is encouraging its use. Building officials in other Western states have also expressed interest in NWCB's document.

The bureau has been giving training classes to building officials, architects, contractors, manufacturers and suppliers on its newly published standards. To obtain a copy of NWCB's Field Technical Document #401, "Suspension Systems for Acoustical Lay-in Ceilings," visit www.nwcb.org.