Use of SE stamp
Use of SE stamp
(OP)
I have been asked to stamp an agri-business structure with my SE stamp for loads less than the ASCE 7 prescribes. This structure is actually going in an area of the US that does NOT require buildings to follow any code or design standard. So for argument sake, is it wrong, or dangerous to use an SE stamp to give a building owner the confidence that a structural engineer has designed the building for a windspeed of 75mph when all engineers know good and well that the ASCE 7-05 has minimum windspeeds of 90mph? This is what the owner has asked for because he doesn't want to pay for what it would take to design it to a 90-mph wind speed.
Put another way, is it my "right" as a design professional to use my stamp to "certify" whatever I want so long as I state the criteria by which I'm stamping it, or does the mere fact that I obtained the stamp bind me to follow generally accepted documents like ASCE 7 regardless of whether there is an AHJ stating that there is a code or standard to follow?
Thanks
Put another way, is it my "right" as a design professional to use my stamp to "certify" whatever I want so long as I state the criteria by which I'm stamping it, or does the mere fact that I obtained the stamp bind me to follow generally accepted documents like ASCE 7 regardless of whether there is an AHJ stating that there is a code or standard to follow?
Thanks






RE: Use of SE stamp
From a practical standpoint, I find that nobody reads a disclaimer or note anyway, and if you stamp a drawing saying it's good for 10 mph wind speed, the interpretation is that "It's good!".
RE: Use of SE stamp
Anybody with a contrary opinion or is this how the majority of engineers feel out there?
RE: Use of SE stamp
you said agri-business. warehouse? that's how I'd go about it if there are no codes governing.
RE: Use of SE stamp
if it is in a 90mph wind zone, you have to follow 90mph wind speed to do design/checking/sealing. However because it is an agri-business structure, you can use I = 0.87 in the design/checking/sealing, which in the final result will be equivalent to a 83.9mph wind with a occupancy category II building.
RE: Use of SE stamp
Chrislaope............at least the way I understand the ASCE 7, it doesn't matter if I can use an I = .87 because the 10psf wind pressure on the vertical surface ALWAYS trumps and I'm stuck with pressures that are 150% - 250% higher than what I get by calculating with the coefficients. I wish I would find out that I'm looking at that incorrectly, but that minimum stuff controls regardless of the I.
Thanks.
RE: Use of SE stamp
The standard of care is, generally, that level of service ordinarily provided by other competent members of our profession, providing similar services in the same locale and under the same or similar circumstances.
Just because it has "always been done that way" for non-critical agricultural buildings does not necessarily establish a standard of care. If you want to proceed, then document and justify your reasons for either deviating from the code or having your design comply with the code.
RE: Use of SE stamp
Maine Professional and Structural Engineer. www.fepc.us
RE: Use of SE stamp
Who is the owner trying to please in terms of building permits, codes and the like if there is no local bldg. code or AHJ? In many jurisdictions ag. bldgs. do not have to meet the bldg. code, with certain limitations. But, that doesn’t relieve the owner of the potential liability if someone gets hurt by one of his inferior bldgs. Then ask yourself if he would have any qualms about suing you, if and when something went wrong. He doesn’t want to pay the little extra it would cost to build the building to meet min. code criteria which are generally accepted/prevailing in the wider surrounding area. And, he wants you to bless the inferior building. It sounds to me that he has some concern about the building he had built and paid for, and is now looking for an insurer of last resort. And, with owners who look on proper design, engineering and construction that way, you can bet your bottom dollar they will sue you if anything goes wrong, all for a small fee to you, now. Tell him to talk to his insurance agent, you aren’t in the insurance business. I certainly would not stamp any plans for this building, but I would review the design and drawings, and tell the owner, in a signed report form, with plenty of caveats and disclaimers, where it doesn’t meet the min. code which I normally work to, with warnings of the potential problems and consequences.
RE: Use of SE stamp
In one midwestern state it (the state) adopted the IBC 2009 and requires its use for state-owned buildings and:
"in any political subdivision which elects to adopt the state building code".
So you might check the county as they may have adopted the IBC.
But if there is no adopted code, no requirement for a permit, no inspector, etc. it seems that whatever you do will be lawful, but not necessarily in your best interest.
So it really boils down to an ethical issue and a pragmatic risk-control issue for you.
Ethical
1. You are providing what the owner wanted, but perhaps the owner doesn't understand the ramifications of that decision. A 70 mph wind is only 60% as strong as a 90 mph. Does the owner understand that not being an engineer?
2. If you design and build to 70 mph, other people besides the owner (the owner's family, friends, visitors, the general public, or subsequent building owners) will all be exposed to a less-than-code building - a higher risk that they would not otherwise be exposed to. This reflects back on Ron's standard of care issue.
3. You, as a licensed engineer need to FIRST look out for public safety and welfare. If only cows or pigs inhabit the building that is one thing - but my guess is that others (see the list in item 2 above) will be in the building.
Risk
1. If you design to 70 mph, and a storm comes in and damages the building, you probably have a good defense (notes on the plans, documentation of your agreement with the owner for 70). So some level of risk control there.
2. But - the owner can always claim they didn't know the ramifications of the 70 vs. 90 and still sue you.
3. Will your professional liability insurance carrier cover you if you don't design to the standard of care? You might call them and ask.
4. Research specific wind site data from a local weather station to see how the average 3 sec. gust wind speeds and standard deviation compare with the national average. In the midwest it might be a bit higher than the national average.
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RE: Use of SE stamp
RE: Use of SE stamp
These are not life safety issues, but I want to be able to point to a standard if questioned.
RE: Use of SE stamp
As engineers, sometimes we can be our own worst enemies by being "too truthful" and offer explanation where none was requested, where none was necessary, or where it wouldn't have been in our best interest to offer an explanation. This is a tactic attorneys use in depositions related to forensic engineering, for example. Get the engineer talking, saying a lot of words, and inevitably they will spill something that is useful to them, even if the engineer didn't actually do anything wrong.
For example...
(Bad)
"Mr./Ms. Owner, if I engineer this building to meet the building codes, which require a 90 mph wind speed, here's what will need to be done structurally. That being said, there is no local requirement to follow 'any code or design standard'. If I use 75 mph, this is all that will need to be done structurally. You'll have a substantial cost savings with the 75 mph design."
(Good)
"Mr./Ms. Owner, here are the signed/sealed plans you requested." (designed to the 90 mph wind speed)
A couple of questions I have... how was the 75 mph wind speed arrived at? If there not "any code or design standard", and if 75 mph is better than 90 mph (economically speaking), why not use 65 mph (or even less) for your wind speed? Why was ASCE 7-05 selected as the code for a building where there is not "any code or design standard"? Why not select ANSI A58.1-72, for example?
You reported that you "... have been asked to stamp an agri-business structure with [your] SE stamp for loads less than the ASCE 7 prescribes". This wording struck me as a bit unusual. Did you actually personally complete all of the structural calculations/plans yourself, from scratch, or is this something that was brought to you by the owner, and they asked you to review it and to sign/seal it, for example? Not that there is anything necessarily wrong with that... I was just curious of the history of the project. Stated another way, are you the first engineer (or design professional of any sort) that the owner has worked with on this project?
RE: Use of SE stamp
PostFrameSE (Structural) (OP):
Reading your post, you say:
“…..at least the way I understand the ASCE 7, it doesn't matter if I can use an I = .87 because the 10psf wind pressure on the vertical surface ALWAYS trumps and I'm stuck with pressures that are 150% - 250% higher than what I get by calculating with the coefficients.”
Just curious, is this agri-business structure a round steel tank? If it is a round steel tank, you might pursued in a wrong direction. I mean this agri-business structure might actually meet ASCE7-05 code requirement, but you just under-estimated the actual structure strength. I have several past experiences that my first simplified analysis and calculations always showed the structure is not strong enough, then I did more detailed and accurate analysis and calculations and found the actual structure is far more strong than I first thought. Just some thoughts for your consideration, please ignore it if not relevant.
RE: Use of SE stamp
This is going to sound really loosey-goosey to many of you I'm sure to hear that a salesman can somewhat dictate some of the responsibilities of the engineer. I'm rarely put in a situation like this, but since I find myself here this time we're having this discussion.
RE: Use of SE stamp
But, I would not be sealing the plans. Provide sealed calculations if the owner wants proof that the structure is capable of withstanding 75MPH winds. Inform the owner that you are unable to seal the drawings because the design wind load is not up to code.
I think that's a reasonable middle ground. You're providing proof it can withstand the client requested loading, but you are not taking liability for the building because it doesn't meet minimum accepted code level values from the surrounding area (even though it is in a non-code governed area).
RE: Use of SE stamp
Have other engineers done that before? That seems to make a lot of sense.
RE: Use of SE stamp
CYA.
I can appreciate that the client doesn't want to pay for a cadillac, just a pinto. But don't give him the impression that it is code compliant.
When I am working on a problem, I never think about beauty but when I have finished, if the solution is not beautiful, I know it is wrong.
-R. Buckminster Fuller
RE: Use of SE stamp
I would be very reluctant to design below standard code requirements - even if the owner wrote me an indemnification letter.
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RE: Use of SE stamp
RE: Use of SE stamp
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RE: Use of SE stamp
Ask you state board for their opinion. Will take a bit longer to get a response of course
RE: Use of SE stamp
If someone came to me and asked to design a stud wall for a 75 MPH wind speed and 20 feet of roof load at 36psf and 15 psf for snow and dead respectively I can do that. It's a design check, it's not accepting liability for the wall that is built in a specific location. It is accepting liability that your calculations for a stud wall subjected to that specific design loading proves it is adequate.
I'm sure if you tried hard enough on any timber framed building you could find enough deviations in construction from the design drawings to render yourself non-liable.
Maybe we're too nice up here in the north. Although we also aren't litigation happy like everyone south of the border.
RE: Use of SE stamp
RE: Use of SE stamp
I wouldn't be stamping a design I'd done for an arbitrary design condition unless the design spec I was passed was stamped by someone taking responsibility for it, or I had some sort of contractual assurance that what I was doing would be only used as a detail to be applied by a knowledgeable engineer. If I didn't have that, I'd be doing my own sanity check on any design conditions I'm given. We're not supposed to be calculation monkeys, we're supposed to exercise our judgement to ensure the safety of the public.
RE: Use of SE stamp
I don't see providing calculations the same as providing sealed plans in certain cases.
A good point is manufacturing equipment supports. I'm not designing to code level values, I'm designing to client dictated values for equipment.
I'm likely off-base, and if it were me in Postframe's position my mentality might be different. However,I see the owner wanting some assurance that his building has been designed to 75MPH regardless of what the code level values are. How else, besides an engineer providing calculations, is he supposed to have that assurance.
So many of you are scared by litigation that you aren't willing to look outside the box.
RE: Use of SE stamp
RE: Use of SE stamp
I suppose if on the first page of the calcs in 70 point font says "This design does not meet code and is approximately adequate to support only 70% of the required wind load", it could work. Weird and pointless to stamp it, and nothing but a potential headache for the stamper, but to each his own.
RE: Use of SE stamp
I do all sorts of industrial stuff and strange installations with my own invented or client invented design requirements, but in those cases you have a couple of things:
1) There isn't a code or widely adopted standard that explicitly covers the scenario. That means there isn't a documented practice that a reasonable engineer would follow.
2) Often your client is knowledgeable and sophisticated. They are either engineers themselves or experienced in industry. They understand the design basis and consequences.
3) There is no access for the public in general.
4) There's generally a good basis for the loads and, if anything, conservative safety factors on the unusual loading. Low safety factors are justified and defined when they're used.
5) If the property changes ownership, there's likely records and the person who would be involved in operating the equipment will likely understand (1) and (2).
Number 3 might be true for an agricultural building, but 1, 2, 4 and 5 likely aren't.
For a building type structure in the US, ASCE-7 is the practice that a reasonable engineer would follow. You can certainly have reasons to deviate from it, but you've got to have a reason. Stamping something with an inadequate design basis seems like it's ignoring the most fundamental part of the structural engineering process. Developing the applied loads has the largest effect of anything in the design process (except possibly establishing the basic load path). Not establishing that those meet a reasonable level of safety seems like it would be bad practice. A stamp doesn't certify that the math is right. It means that what's been designed meets some reasonable level of safety and engineering practice. If I deviate from standard industry practice I need to explain why and then I own that deviation.
If designing an agricultural building to a lower windspeed seems reasonable, I can go ahead and stamp it, but by stamping it I'm certifying that I think it's a reasonable design practice. If something happens later on, I own that choice morally and legally. Pointing at a salesman and a layman owner because they gave me a design basis doesn't work.
I'm not saying that a lowered windspeed isn't defensible somehow, but determining and justifying that needs to be done by the engineer involved in the project.
RE: Use of SE stamp
RE: Use of SE stamp
RE: Use of SE stamp
TTFN
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