While that may be a practical way of doing some things, it has no place in construction documents. For those, we have a different rule: Say it once in the right place. I think it’s safe to say that specifiers believe this rule, though convincing those who create the drawings is difficult; the result often is that the specifications may state things but once, while it’s common for drawings to repeat things many times, and it’s also common for drawing notes to repeat what is stated in the specifications.
So what’s the big deal? Why not repeat things?
I believe the intent is good, and that everyone working on drawings or specifications simply wants to make sure the contractor knows what is needed. That’s the theory, but what really happens? In the next couple of articles, we’re going to look at unintentional redundancies.
Let’s start with specifications; it’s quite common for a specification section to say the same thing twice. Here’s an example I have used when teaching specification writing classes. It’s from a specification I found online, but the same problems are found in manufacturers’ specifications and in commercial guide specifications.
A. Flat roof board insulation: Extruded polystyrene board to ASTM C578, Type IV, rigid, closed cell type.
1. Thermal resistance (ASTM C518): R-5 per 1 inch of thickness.
2. Board size: 24” x 96”.
3. Board thickness: As indicated on the Drawings.
4. Compressive strength (ASTM D1621): Minimum 25 psi.
5. Water absorption: 0.7% by volume maximum.
6. Edges: Square.
7. Water vapor permeance (ASTM E96): Maximum 1.1 perms.
That looks pretty good, right? Not really. Here’s the problem: Much of the information in the numbered paragraphs is already required by ASTM C578, and is, therefore, redundant.
2.02A. ASTM C578 – Standard Specification for Rigid, Cellular Polystyrene Thermal Insulation, is, as the title states, for rigid polystyrene insulation. The standard states that the insulation shall “have essentially closed cells.” The standard also states the following requirements for Type IV insulation:
- R value: 5 per inch.
- Compressive strength: Minimum 25 psi.
- Water vapor permeance: Maximum 1.1 perms.
The stated water absorption is a bit of a mystery; ASTM C578 allows only 0.3 percent, while the specification allows 0.7 percent. I can’t tell if this is a typo, or if it’s measured by the same standard.
If we remove the redundancies, along with 2.02A.3 – a needless statement – we’re left with this:
A. Flat roof insulation: ASTM C578, Type IV.And that could be further reduced to a single statement by including the subparagraphs in the main paragrah. Instead of 9 paragraphs and 71 words, the insulation can be specified in a single paragraph using 14 words.
1. Board size: 24” x 96”.
2. Edges: Square.
The usual objection I get is, “So what? What’s a few extra words? They’re correct, aren’t they?”
They are, but why are the requirement restated? Doing so adds nothing; more important, one could argue that because only those performance criteria are stated, the specifier doesn’t care about the other things required by ASTM C578, such as density, flexural strength, dimensional stability, oxygen index, the test temperature for the R value test, or acceptable defects. Part of the problem is that specifiers often state requirements that don’t matter, simply because they’re in a manufacturer’s specification.
The usual counter is, “Of course we want all that, too. The contractor has to provide it because it’s part of the standard.” If that’s the argument, then why list any of the properties required by the standard?
Another argument is that specifying those properties makes it easier to review submittals. I suppose that’s true, but again I ask, what about the other properties?
Another problem with restating parts of the reference standard is that doing so introduces another possibility for conflict. In this case, it’s quite possible that the specified water absorption is a typo. Another possible problem arises when a person unfamiliar with the standard changes the Type, say, from Type IV to Type V, and doesn’t change the compressive strength.
Virtually any reference standard contains a multitude of requirement, some stated, some incorporated by reference. Their value lies in the fact that requiring compliance with them automatically makes the entire standard part of the contract documents. Selectively restating selected parts of those standards is not only unnecessary, but it suggests that the few things cited are the only ones that are important.
Another redundancy in specification sections is created when a manufacturer’s instructions are included in the section. A simple “Comply with manufacturer’s instructions” makes those instructions part of the contract documents. It also avoids problems created by incorrect copying, and by changes in the manufacturer’s instructions.
Further complicating the issue is the fact that different manufacturers may well have different instructions. If a specification section is based on Really Great Coatings Super Stuff, which is applied at 30 mils, but you get Coatings-R-Us, which goes on at 60 mils, the specification is simply wrong. You could address the problem by specifying requirement for one product, followed by “Or other as required by manufacturer” but why not take it a step further, and simply require compliance with the manufacturer’s instructions?
Of course, your personal experience may have been that you want something other than what the manufacturer requires. If that’s the case, you may be justified in changing the manufacturer’s instructions. Be aware, though, that if something goes awry, the contractor may well blame the problem on you.
Next time, we’ll look at how specifications frequently repeat requirements stated in Division 00 and in Division 01.
© 2015, Sheldon Wolfe, RA, FCSI, CCS, CCCA, CSC
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