That's sort of a gray area and depends on the circumstances. If done properly, it's legal but not always prudent.
The seal is taken to mean that you performed the work. Assuming you did perform the work, no problem there.
If the seal is used on a particular project, it is also taken as a certification that the engineering on that project is proper, meets the required codes, etc.
You may analyze the bus shelter for typical snow, wind, seismic loads, and all is well.
Then the contractor gets a contract for bus shelters in the ski area, xeroxes off your calcs, and sends them in as part of his submittal. So maybe your calcs were based on 25 psf and in the ski area, it's supposed to be 250 psf.
Now, technically, you can get around this by being very careful in your design to spell out where it's applicable, the maximum wind, maximum seismic coefficients, maximum snow, what year of which codes it meets, etc. The problem with this is that there is a tendency in the real world not to read a lot of this fine print and just send it in anyway. (Or the contractor may read it and just not understand what some of that means, anyway.)
And of course, different government rules change, so what's adequate now may or may not be adequate 10 years from now.
One of the big rules I learned when getting into stamping odd bits and pieces is that you do not stamp anything without a project title, a date, and an address.
Of course product suppliers want a blanket engineering standard template that is stamped. but its not ok. how would the design of that bus shelter change if it was near a slope, in a high snow load zone, high wind? Next to a truck loading ramp?
what the supplier wants to do is circumvent all future engineering requirements by using your stamped document for all future projects, without your oversight or input. If something goes wrong, or comes up legally, it will be coming back your way - for a project that you've never heard of.
Gus2015.....is this for a government agency of any sort? If so, does your contract provide that you maintain ownership of your documents or did you give that up. If you gave it up, you have a more difficult time with controlling how your signed/sealed plans will be used. If you did not give up ownership of the documents, then you have more control over their re-use.
As a rule, in my company we do not give up ownership of documents.
Gus2015:
That’s good, you engineered it and stamped it. And, as they sell these, you are opened up to 735 different potentials for liability problems (law suits, etc.) on installations which you have no control over. They do whatever they want in terms of installation, local soil conditions, code requirements, and local AHJ, etc. and since you signed the plans, all you get is the liability if anything goes wrong. You better protect yourself against this, because it’s your PE license, stamp and reputation if the company won’t fully protect you.
I'd agree with above posters, your E&O policy might consider that a "product" and may not cover it. In my last re-up, the agent wanted to know if we designed "solar panel frames"....Lot more risk to them with a product then a specific application.
My current company does a decent amount of design for repetitive buildings and installations around the country. Most of them, we have a calculation template, but we create a new calculation package and drawing set for each installation or project. For others, what we've done is take a "worst-case" design and created a calculation package. Then for each new installation, we check that the local loads, code requirements, etc. don't exceed the demands used in the "worst-case" design. Our calculation package indicates the local requirements and compares them to the "worst case" design (ie - design wind speed is 120 mph at the site, wind speed in our "worst-case" design is 130 mph. So we've got enough capacity for the localized wind loads). This works for maybe 80-90% of the projects, but every so often we have to increase capacity somewhere for a localized design condition (higher snow drift, seismic demand, etc.)
This really only works on simple designs. I have yet to encounter an engineer that is willing to admit that they stamp a "Blanket calculation" that can be used anywhere in a specific state. In my opinion, there's no upside to it for an engineer. As others have mentioned, you're getting paid for one installation, but taking liability for as many installations as the client wants to build. It's also my opinion that you can't truly account for every possibility, so to stay within your ethical and legal responsibilities, you have to look at every location or installation individually. In my experience, you can do these repetitive projects efficiently and ethically as long as you are able to explain to your client the reasoning behind your position.
For standard manufactured assemblies like bus shelter, sheds, whatever, a generic drawing and worst case scenario is absolutely acceptable. The point is that you have clearly indicated on the drawing that this is good for up to X size, for up to Y wind load, for up to Z snow load, etc. If the project fits, your design is valid and they are good. If it doesn't fit, you've already said you do not take responsibility for it. How do you think any manufactured product makes it to market? Do you have a furnace in your house? A water pump? Have you ever climbed a scaffold?
For a straightforward item, if you define the loading conditions it's acceptable for, then there's a way to do this reasonably. Basically, don't qualify it for use anywhere in a state, instead decide on the loads and conditions it's acceptable for and qualify it for those with clear design basis notes. Maybe you can select a loading envelope suitable for the entire state, but leave determination of the actual site conditions to an installation specific review (i.e. say it's rated for some wind speed and snow conditions in certain exposure classes with any reasonable limitations you can think of, not that it's suitable for some geographic area). On anything that isn't stupidly basic, you can put a big 2 inch tall note on it saying that the drawing needs to be accompanied by a stamped document from a professional engineer certifying that a particular installation falls within the design conditions on the drawing and any other similar requirements.
It's a reasonable compromise where the client knows that an engineers won't redesign this item every time they use it because they disagree on good detailing practices, or what effective length to use for bracing design, but requires that an engineer actually reviews the site and site conditions.
You should also be charging a larger fee for something like this, spending significantly longer on quality control and brainstorming possible issues, and making sure your insurance is happy.
This is how standard drawings are generally treated. One person engineers them for various conditions, and then it gets verified by the user (engineer or otherwise depending on the type of item) that things fall within the design basis.
