Weak in Faith, part 2 - Specifiers vs. Master Guide Specs

by Sheldon Wolfe, RA, CSI, CCS, CCCA



it is difficult to enforce the requirement that "The window shall feel solid"

part 1:  master guide specs vs. the MOP

part 2: specifiers vs. master guide specs

part 3: specifiers vs. the MOP

 part 4: specifiers vs. themselves

 

Product manufacturers have an understandable tendency to offer guide specifications that favor their products; they typically write specifications that require products to be identical to their own. The manufacturer of nine ply doors will specify that doors be constructed with nine plies, even if that construction is irrelevant to the performance, appearance, or quality of the door. There will likely be no mention of five ply or seven ply construction, even if they work equally well.

The same guide specification might also specify a minimum face veneer thickness of 0.005 inch if that is what the manufacturer uses; there would be nothing to indicate that even the lightest sanding would wear through the face veneer. Similarly, the manufacturer who uses only 1/2 inch face veneers would specify that as a minimum thickness, even though there is ample evidence that thinner veneers perform adequately.

Obviously, a specifier has to have some idea of what works, what affects performance, and what is unimportant, and specify exactly what is needed - no more, no less. Otherwise, it will often be impossible for more than one product to comply with the specifications. Granted, there are times when only one product will do exactly what is needed, but the vast majority of products are not sufficiently unique to justify sole-source specifications.

Compliance is a black and white issue. A given product either does or does not comply with the specifications; "almost complies" is not acceptable. If a thickness is specified as 0.125 inch minimum, then 0.120 is non-compliant, and so is 0.125 inch nominal. It is or it ain't.

It often happens that non-compliant products are accepted after award of contract. There is nothing inherently wrong with acceptance of substitutions; certainly, it is in the owner's best interest to accept substitutions that offer the same performance at lower cost or better products at the same cost. When the specifier does find that a product is acceptable but does not comply with the specifications, it is time to change those specifications.

The absolute requirement for compliance is an excellent reason to use performance rather than descriptive specifications. If a window's deflection under specified conditions is acceptable, does it matter if the wall thickness is 0.09 or 0.125 inch? If a condensation resistance factor of 60 is specified, does it matter if frame members are poured and debridged with a minimum separation of 1/4 inch? If the manufacturer can meet the performance criteria with 0.05 inch wall thickness and no thermal break at all, why is the product not acceptable? It may indeed fail to meet some other requirement, but that requirement should be quantified. It is difficult to enforce "The window shall feel solid."

The specifier who has the owner's best interest in mind will not slavishly copy a manufacturer's guide specifications, but will examine each requirement and modify it as required by the needs of the project.

2000 Sheldon Wolfe, RA, CSI, CCS, CCCA, swolfe@bwbr.com
on the web at www.CSI-MSP.org 

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