Selected Answers

From Michael Halliwell of Thurber Engineering Ltd. on December 8, 2014:
I know that there can be a lot of ambiguity in “or ...read more I know that there can be a lot of ambiguity in “or equivalent,” but as to the “who decides” I think it depends on what is being specified and how it is specified. I know that for environmental liners, we usually give 3-4 performance parameters for which several products would meet the requirement. Sometimes, a specific product is mentioned, but the performance numbers are the bigger part of the spec. If their preferred brand meets the performance parameters, it's equivalent. If a client wants to specify "Brand X,  Product Y or equivalent," I know a lot of contractors will look at spec sheets, find the competitor's product that is cheaper and close to the same specs, and then ask the question to the Owner, "is this okay?"

From Philip Kabza of SpecGuy Specifications Consultants on December 5, 2014:
The key to applying the term “equivalent” or “comp ...read more The key to applying the term “equivalent” or “comparable” (which I prefer) is evaluating the proposed product with respect to the Owner’s design requirements. Two products may not be identical. The basis-of-design product may have several characteristics that significantly exceed the proposed product; however, if the Owner does not require that excessive a level of performance, the design professional is not inappropriate in approving the substitution. Obviously, the more closely the basis-of-design product represents the Owner's requirements, the better the original specification. But this system of specifying is intended to allow the Owner to maximize value, and when handled properly, it does.

From Michael Quaranta of OPERATIONS 40 on December 2, 2014:
Two great selected answers. What would the world ...read more Two great selected answers. What would the world of construction materials be like if there was a true sustainability certified documentation for a given product listing, say exterior building wrap, both fabric and liquid. Which one would qualify as the equivalent? Under a certified sustainability specifics documentation, the "differences" and commonality of performance would be in verified test data and MSDS/SDS reports for a meaningful decision to substitute as an equivalent. However, this documentation does not exist. The question is faulty when asking to locate a given equivalent- there aren't any except in the specification writer's mind and the contractor's opinion. And the last part of the question points to the age-old consensus/marketing product "standards" with the hope you made the right replacement selection that will meet the meaningless stated authorization for an equivalent, with a suitable warranty.

From Sarah Geary of RockTred on December 2, 2014:
To follow up on Jeffrey’s comment: Many times “or ...read more To follow up on Jeffrey’s comment: Many times “or equivalent” may mean “I’m sure there’s another system out there that is capable of performing similarly, but I do not have the money, time or interest to find and qualify any more product systems." Testing a system's compatibility can be very time consuming and costly. I guess it loosely follows the saying "If it isn't broken, don't fix it.Why look for another solution when I know this specific one works?"

From Jeffrey Stewart of Avalotis Corp on December 1, 2014:
What “or equivalent” should mean is similar chemis ...read more What “or equivalent” should mean is similar chemistry and performance properties. The true answer lies in the second part of your question. Only the specification writer can truly answer what he meant by "or equivalent." Some other possible interpretations are, "I'm not really sure, so I'm open to suggestions," or "I'm only going to use the named product but I'm not allowed to officially sole source any product." Because the "or equivalent" is by its nature so ambiguous, it is best practice to prequalify any alternative with the specifier and/or purchaser prior to submitting.