6 Tips for Writing the Perfect In-House Specifications

As the data requirements on construction projects become more complex, it’s crucial that everyone in the value chain, including architects and structural engineers, operate under the same set of project requirements — the project specifications.

Your project specifications serve as the field guide for the construction team. Here are 6 details that can reduce the need for field clarification, eliminate change-order requests, and help avoid cost overruns.

Help your framing contractor to have the most flexibility on the job site by including AISI S220 and AISI S240 standards in your in-house specifications.

6 Details to Note

1. Flange Sizes

Product innovations are part of the industry’s evolution. But, such changes can hinder projects if your specifications related to CFS framing are out of date. Here is an example.

Minimum flange sizes: The latest code — the 2018 IBC which references AISI — allows for structural track with a 3/4” flange (AISI S240). That differs from the ASTM C955 standard which requires a minimum 1-1/4” flange for structural track. The standard for nonstructural track is a 1” minimum for both ASTM C645 and AISI S220.

• If an architect specifies ASTM, then the structural track will be required to have 1-1/4” flanges
• On structural track, a 3/4” flange (AISI) vs. a 1-1/4” flange (ASTM) is a relatively large variance that could raise the framing contractor’s costs and slow down its work

2. EQ (Equivalent) Studs

In the past, CFS framing manufactured in the United States came in standard thicknesses, tensile strengths, and profiles. But, some CFS manufacturers began engineering products known as “EQ” or equivalent studs.

• EQ studs are nonstructural CFS framing members with performance similar to traditional CFS members. They have a reduced base metal thickness, but a higher strength steel
• Framing contractors can build a quality wall using EQ studs
• The 2018 IBC has no issue with the use of EQ stud products, because AISI, the sole standard referenced by the 2018 IBC, is performance-based and sets no minimum thickness for CFS studs
• This contrasts with ASTM, which sets a minimum thickness for nonstructural steel framing at 0.0179 inches, or the equivalent of a 25-gauge stud. ASTM C645, however, allows for equivalent thickness with testing

What if your specifications list only ASTM standards for CFS framing? Then, based on the above points, your framing contractor will have less flexibility in choosing studs.

3. Other Industries

Other industry’s set standards that affect steel framing. Here are two examples:

• Tile Council of North America calls for a 33 mil minimum CFS steel thickness spaced no more than 16” o.c. for walls covered with tile
• Gypsum Association recommends CFS framing with a base metal thickness of 30 mil (0.0296”) when using cement boards, tile backer panels, and high-performance gypsum panels designed for increased abuse-resistance construction
• GA makes some allowances for thinner steel studs — down to a 0.019” thickness — on certain designs, so long as they are fastened with sharp-point, fine-thread screws (or sharp-point, high-low thread screws) using a screw gun set to 2500 RPMs

4. Costly Details

Some specification details can be a challenge to execute in the field. For example:

• While zinc coatings protect against corrosion, a specification may state, for example, “G90 for a nonstructural wall,” when the minimum code requirement is far less strict. Since zinc is expensive, this small error can result in significantly higher costs

5. Out-of-Date References

Some specifications reference publications that are hard to find or no longer exist.

• One specification stated, “Comply with LGSEA Research Note.” This publication would be hard to find, because LGSEA became CFSEI 15 years ago

Anyway, it’s better to reference manufacturers’ product data sheets for their superior reliability.

6. Out-of-Date Lists

Architects issue lists of approved manufacturers for their projects. Normally, this is helpful,  but …

• Many steel framing manufacturers have merged, gone out of business, changed names, or operate far from a given project

More Information

Check out these additional articles on specifying CFS framing:

• Complying with New Codes and Standards for Cold-Formed Steel Framing
• Cold-Formed Steel Framing Quality Assurance and Quality Control