Inspection of Roof Framing 3

[radiocontrolhead]

I'm being asked to come in and to inspect roof framing for a commercial steel framed roof of a 22,000 sq ft roof.

They perform chemical processes that with time evaporate and corrode the roof framing.

They've asked me to come by to inspect the framing and make sure nothing is out of the ordinary and that I prepare a sealed report stating as such. To my knowledge, and to theirs, nothing is damaged or out of serious disrepair but they want to take the necessary measures to have someone with knowledge observe the framing for concerns.

My question is. How much liability am i taking on with something like this and what should I be careful about stating in the report? I clearly cannot assume liability of the structural design of the building but will preparing a report like this switch over that liability? This is where I'm pretty confused and trying to exercise caution.

Another question is: Should engineers even perform inspections of this type or leave it to licensed inspectors?

 

[r13]

Should engineers even perform inspections of this type or leave it to licensed inspectors?

Yes, I would, or bring an expert with you. Unless you are quite familiar with corrosion.

 

[XR250]

Seems like you would have to analyze the framing to determine if any section loss has affected its capacity. It may be undersized from the get go. I typically stay away from these types of jobs.

 

[EdStainless]

I have seen issues with roof, joists, crane rails, and utilities from acid fumes. Get some experienced assistance.

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P.E. Metallurgy

 

[radiocontrolhead]

Thanks all.

I might have to turn this one down.

Can someone point me to who I should turn to or at least refer to for this type of job? Would it be a structural steel inspector?

 

[radiocontrolhead]

Would i need to look for a steel frame inspector? or a metallurgy building inspector?

this is something that has to be tested/investigated in-situ

 

[StructEngBrah]

I'm assuming this is an existing structure that the owner has had for a while and not a brand new building. My firm takes on jobs like this quite a bit, especially in the refining and petrochemical world. The amount of liability you take on is proportional to how you write the report.

Establishing the client’s expectations up front, typically with a detailed proposal stating what you will and will not do is critical. You will not be looking at the building and guaranteeing that it was designed correctly or that the building will perform for an infinite amount of time. You’ll be surprised how many people are expecting you to, but once you explain it, I find clients are receptive. If a client wants that peace of mind, you can propose to analyze the building and see if it meets building code requirements. Once a client sees the cost of that, they typically decide they don’t need that.

We typically do not call our services an “inspection”, because that typically implies a level of detail we are not comfortable with, and lawyers can kind of attack you with that word. We typically call a job like this a visual assessment. For a job like this, I might measure some remaining thickness with either calipers or UT measurements, to get a feel for section loss. So that might kick it to a visual and tactile assessment.

Typically for a job like this, I’ll do a visual and tactile assessment. If I find section loss greater or equal to 10% of the element thickness, I’ll say, hey you might want to look into this more. This could have reduced the as-built capacity of the framing. That would be a separate service potentially involving structural analysis of the framing and maybe even repair drawings if it is warranted. I kick it back to the client to make the decision whether to investigate stuff more. If something is really chewed up and dangerous, I make that clear in the report as well. The 10% rule is a rule of thumb, you have to use judgement on these things. For something like an OWSJ that are designed to the gnats ass, 10% could be a big deal in terms of not meeting code anymore.

We include a paragraph at the end of our reports that limits our exposure. It basically states there could have been hidden conditions we didn’t see, or conditions that develop over time that are not reflected in our report. We reserve the right to change our conclusions if other findings are discovered.

Working for chemical manufacturers or other plant like facilities can be kind of a pain in terms of safety requirements and working around equipment. They might make your come in at odd hours when they aren’t operating or go through a bunch of safety training. Make sure to include potentially headaches working with these types of facilities in your cost estimate.

Sorry for the long post. Hope it was useful!

 

[EdStainless]

The last time that we did a detailed assessment of our pickle bay more than half of the cost was scaffolding and safety related. And yes it had to be done over a weekend.

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P.E. Metallurgy

 

[Forensic74]

I would first consult with an engineer familiar with corrosive environments, or do reasonable research, to determine how much hidden issues can exist. If there's not too much potential for hidden damage, I'd probably move forward.

This is a niche issue so, it could be an engineer or inspector.

You just don't want to give the owner the impression that a visual inspection is good enough.

 

[EdStainless]

One thing being done these days is to do a detailed drone visual in order to get a general idea and identify locations of interest for more investigation. The flight paths are programed from the building drawings and you get video of the entire structure up close.
One issue with this though is that if there are areas that look concerning there really is no option other than proceeding with more detailed investigation. But it does let you break it into stages.

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P.E. Metallurgy

 

[radiocontrolhead]

this would be really more of a visual assessment and a professional opinion . I am trying to remove all liability and simply come in to make observations and note any recommendations that might need to be looked at closer.

I've been considering purchase CASE contract #6 but i'm not sure if it will have what i need to fullfill my objectives in writing this proposal.Anyone have experience with this contract?

CASE #6 - An Agreement Between Client and Structural Engineer for a
Structural Condition Assessment