Tolerances 1

[haynewp]

I have a project with both a separate quality control company hired by the contractor as well as the owner’s special inspector. Our specs have the references to ACI, AISC etc.

I got an RFI to provide the maximum offset permitted in some vertical rebar. My response was to see the specs and the referenced standards and that the contractor should be familiar with and checking all tolerances. But now I am being asked to list out all the tolerances from the standards referenced in the specs. This is currently for concrete, but I expect it will carry over to the other materials on the project. Has anyone ever gotten this kind of request before or had a project where nobody was familiar with checking tolerances?

 

[phamENG]

Here you go for concrete: ACI 117

What other materials do you have?

I haven't had this happen...sounds like they're either used to working with somebody who does that or they've found it's a good way to put the project engineer off his/her footing. You either send them an exhaustive list that they can turn around and say 'see, they don't know they're talking about - they're just listing everything' or you pick out the stuff you think is applicable but when you miss one and try to enforce it, they scream foul and say that you told them they didn't have to follow it. (Sorry, I've been in residential too long...I have a very jaundiced view of contractors.)

 

[flight7]

Your initial response that the contractor - and the special inspector - should be familiar with the tolerance requirements and where to find them in the specs was a good one. I would never take on the task of listing all tolerances which might apply to all materials on a project. For one, it would take a LOT of hours. And inevitably something will not be included which will turn out to be important, and you'll get the heat for something that should be the contractor's problem.

 

[phamENG]

Hmm...did you check to make sure that the specs do, in fact, identify that tolerance? Because if there's a spec book and it's not in there, and you told them to go look for it there, this could be their not so subtle way of making you admit to not putting it in the spec book.

If you didn't specifically reference ACI 301 or ACI 117 in your specs...then it's probably not in the contract. The building code doesn't reference either of those. It's incumbent on the engineer to either copy and paste them or invoke them in an enforceable manner in the specs/notes, etc.

 

[DrZoidberWoop]

The large standardized industries (concrete, steel, etc.) have established "codes of standard practice" you can refer the RFI author to, in a general manner, without making yourself a scapegoat/target for the site's future non-conformances. Exceptions could be proprietary systems and things like curtain wall or glass fixtures, in which there should be a "shall" type note requiring coordination between subcontractor and the proper responsible party.

 

[haynewp]

Our specs reference the required standards, ACI 117, ACI 336.1 etc..

 

[JStephen]

ACI 318-05 has Section 7.5.2.1 and 7.5.2.2 with some tolerances.
ACI 318-14 lists ACI 117-10 in the "Commentary References", first ACI item. I don't know where it's referred to in the commentary, though.

 

[phamENG]

Our specs reference the required standards, ACI 117, ACI 336.1 etc..

Figured as much. You should be fine then. I'd just refer them to that "and any other relevant tolerances listed in the specifications or drawings" and be done with it.

ACI 318-05 has Section 7.5.2.1 and 7.5.2.2 with some tolerances.
ACI 318-14 lists ACI 117-10 in the "Commentary References", first ACI item. I don't know where it's referred to in the commentary, though.

ACI 318 is a design spec. I got burned by this as a junior engineer working on a big government job. I made a similar reply...'such and such is required by ACI 318'...the owner's engineer (the government reviewer) roasted me alive that response. Contractors are responsible for industry norms/specs (like 301 or 117), the project contract documents (drawings, specs, etc.), and the building code in terms of general knowledge of the primary document. They aren't responsible for an in depth knowledge of every referenced design standard - that's our job. If there's a requirement that needs to be communicated that isn't otherwise communicated by the industry specs, we need to convey it in our own.

 

[JStephen]

"Building Code Requirements for Structural Concrete" is right there on the cover.
"This Code provides minimum requirements for the materials, design, construction, and strength evaluation of structural concrete members", etc. in 1.2.5.