Use and misuse of GA numbers

Specification & Product Discussions Specifications Discussions
1

Currently, I am working on a project where the architect has assigned Gypsum Association file numbers to the wall and ceiling assemblies.

I look up the specific assembly numbers and tell the architect there are some issues, namely:

  1. Some of those systems indicated on the drawings have been discontinued and are no longer listed in the current (2024) edition of the GA-600 Fire Resistance and Sound Control Design Manual.

  2. Some of those systems your indicate are proprietary and not generic. No contractor is going to use different manufacturers’ gypsum boards in various locations of the building.

  3. Some of the assemblies you detailed are not precisely the assembly indicated by the GA number.

My comments either fall on deaf ears, or I get the response that is the way they designed the building.

Luckily, I have never heard of a building inspector catching those issues.

What has been your experience?

2

This problem was much more common in the past, the 1990’s and 2000’s, when a single manufacturer had paid for the required testing for a specific wall type, and others had not, or perhaps were quietly trying to sneak by. It was a beloved “gotcha” of OSHPD, the California state authority that reviews and approves hospitals.

3

For fire rated assemblies, I try to advise our clients that the ICC codes allow for prescriptive compliance permitted by IBC Section 721. This is especially important for concrete masonry units since production plants capable of applying UL labels are limited and may preclude using a manufacturer local to the project.

4

  1. The edition of GA-600 is dependent on the IBC edition adopted. For example, the latest published IBC edition, 2024, references the 2021 edition of GA-600. Thus, no IBC edition, yet, has adopted the 2024 GA-600.

  2. Although the IBC only allows those systems identified as “GENERIC,” the systems identified as “PROPRIETARY” typically have UL assemblies associated with them. I advise my clients that if they want to use a proprietary GA-600 assembly, they should use the UL Design Number instead of the GA File Number.

  3. Whether using a GA or UL assembly, there are options permitted in many of those that are not indicated on the accompanying illustrations. Also, GA’s “General Explanatory Notes” and UL’s “Design Information Section” provide options for their respective assemblies (e.g., additional layers of gypsum layers, addition of wood structural panels in an assembly, etc.).

5

Ron,

Thank you for your response. I did not know that the Code references a specific dated GA-600 book. I always thought it was the latest edition per bid date.

Your 1) presents an additional problem. Some of the numbers the architect has indicated on the drawings are new to the GA-600 2024 edition and not in the 2021 edition. (I had to buy the 2024 edition to double-check the architect’s numbers.)