Webinar Q&A

Gypsum resources for better design

Attendee questions

Gypsum Resources for Better Design webinar on November 29, 2022

Where are the third-party testing references found in The SoundBook and how can I access the testing reports? I am looking for the details, like fastener spacing.

The third-party test for each assembly included in The SoundBook® is noted to the right of the Sound Transmission Class (STC) value designation and under the assembly image. The test report will start with the letter combinations NGC, OL or RAL. The letters designations refer to the independent testing lab where the test was conducted. You can also contact your regional construction design manager to get a copy of the test.

Some local code officials do not accept the rated assemblies provided in the Gypsum Association’s GA-600 “Fire Resistance and Sound Control Design Manual” stating that only UL (Underwriters Laboratories) designs or IBC (International Building Code) assemblies are acceptable. Is there documentation available that shows GA-600 assemblies are code compliant?

In Chapter 7, Section 722 “Calculated Fire Resistance” of the International Building Code (IBC) there is a footnote Tables 721.1(1)(2)(3) that says: Generic fire-resistance ratings (those not designated as PROPRIETARY in the listing) in the GA-600 shall be acceptable as if herein listed.

Do you have guidance on adding a door in an area separation wall used as a fire wall in multistory apartment buildings?

Yes, we do. Refer to the “Area Separation Fire Walls” section in The Wood Book™ for more information.

In a fire-rated assembly with gypsum board on one side only, can I assume that the fire exposure is only on the gypsum board side of the assembly?

All UL fire-rated systems are rated from both sides unless noted otherwise in the design. UL design V497, which has gypsum board on only one side, is rated from both sides. UL design U356 is specifically labeled as rated from the interior face only. Section “VI. Walls and Partitions” of the UL General Information for Fire-resistance Ratings - ANSI/UL 263 Certified for United States Design Criteria and Allowable Variances notes: “The ratings for walls and partitions apply when either face of the assembly is exposed to the fire unless indicated otherwise on a specific design.”

I am working on an existing building that has a 1-hour rated wall that needs to be a 2-hour rated wall in the new design but can only access the wall from one side. Is there a 2-hour rated assembly that can be built from one side?

UL design V449 is an unbalanced wall assembly that achieves a 2-hour rating by adding two additional layers of 5/8” Type X on one side of the existing 1-hour rated wall.