tank/boiler ratings

[diesel421]

My boss ordered two tanks that have no plates on them indicating their ratings (MAWP, temps, jacket ratings, etc.). They were purchased used in Nevada and the guy he bought them from doesn't have the paperwork as to where he got them, what they were used for, or what the ratings were on them.

One of them appears to be pressure/vacuum rated, and we need to pull a vacuum of -7 to -4 psig. But I don't want to proceed until I know what the ratings are on that tank, even though it's a fairly low pressure low vacuum application. It is currently used as a mildly heated, vented settling tank.

What legal rights do we have in terms of getting documentation for these used vessels? We bought it in NV but we use it in CA.

Thanks!

 

[metengr]

diesel421;

One of them appears to be pressure/vacuum rated, and we need to pull a vacuum of -7 to -4 psig.

How do you know this if you mentioned in your post

My boss ordered two tanks that have no plates on them indicating their ratings (MAWP, temps, jacket ratings, etc.).

If these are storage tanks and they were purchased with no bid specification as to materials of construction, you have no legal right for anything other than the tanks themselves. You could do your own evaluation for suitability for service or you can convert them into planters.

 

[unclesyd]

It would help if you could post the sizes, material?, and thickness.

Maybe someone from CA will step in as CA did have some very stringent requirements on used process equipment. It isn't any easy task to evaluate any equipment for a specific set of conditions. If you have to use this equipment I would retain someone well versed in the design and evaluation of pressure vessels.

A number of years ago it took almost a year to get a high pressure gas cooler approved for use and we had the paper work.

 

[jte]

Oddly enough, I believe you can meet the letter of the law in California for external pressure service without an ASME code stamped vessel.

http://www.dir.ca.gov/title8/460.html

The (relatively) painless method to get direction on this is to talk to the folks at

http://www.dir.ca.gov/dosh/pressure.html.

I don't work for them - but on occasion I have vigorous discussioins with them and have found them to be well intentioned and intelligent folks. They aren't "out to get you" but are willing to help you work towards a safer workplace and won't come after you for coming to them for guidance on how to resolve this potential issue.

jt

 

[unclesyd]

Since we dealt with them it must be that they have been smoking some of the wacky tobacco from Mendocino County.

That is well and good if they will work with on such a project.

 

[diesel421]

"diesel421;

Quote:
One of them appears to be pressure/vacuum rated, and we need to pull a vacuum of -7 to -4 psig.

How do you know this if you mentioned in your post "

Uh that was the point of the entire post. I want to use this tank to pull this vacuum, but I don't know if I can b/c I don't have the ratings (I said it "appears" to be, not the same thing as know). I want to use this tank for a certain application (low vacuum), but I don't know what the rating of the tank is, and the used salesman would not release information on this. I want to know if he is legally obligated to.

I don't know if you know this or not, but a lot of states require vendors to release boiler and tank properties and I'm trying to find out if NV or CA does this or not.

 

[JStephen]

If your application actually requires that the tank/boiler/vessel be in compliance with ASME or some other code, there's not much you can do. These standards govern how the thing is built in the first place, and there's no way to go back after the fact and certify compliance. On the other hand, it wouldn't be too hard to check if a tank or vessel was adequate for a particular vacuum rating, even though it couldn't be certified as meeting a code for that rating.

I can't imagine why a vendor would have information on a used product and not be willing to pass it along. Most likely, he bought the things for scrap or at a bankruptcy auction or something like that, and doesn't have any information, either. I'm not aware of any law that requires this, though, I would just assume it was prudence on the part of the buyer.

 

[diesel421]

What if we were to hydrostatically test it by pulling a light vacuum on it?

 

[diesel421]

Yeah unfortunately my boss purchased this used a few years ago and they didn't seem to have the information available. It was a "steal" so we ended up buying it, thinking we were just going to use it as an ambient settling tank. I remember I had to sell a tank for scrap for an old company I worked for, but even for scrap I had to submit all the paperwork on the tank with the psig certification details, hydrostatic tests, and everything. And that was just for scrap. But that was NJ so maybe the laws there are different than they are here.

 

[jte]

diesel-

You really need to establish whether your intended application for this equipment qualifies (legally) as a pressure vessel in California or if it is simply a low pressure tank. Huge difference in what your restrictions are depending on how it is classified. I suspect what you intend to do with this equipment would lean towards "not a pressure vessel" which makes your life far easier. Until you know, you are literally wasting your time.

Call the folks I referred you to yesterday and over the phone they will most likely tell you that they are not interested in this tank. At that point you can use good engineering judgement and perhaps consult with an expert on how to establish ratings for the tank.

As far as I'm aware, California has no laws relating to selling used or scrap equipment.

 

[MJCronin]

You could move your business to China....

Problem solved !!!

 

[InspectorJim]

Most states have laws for pressure vessels subject to internal pressure, not under vacuum or external pressure. We often confuse this because many vessels are rated for both (internal and external) pressures as stamped on their Code nameplates. Check with your jurisdiction to find out if vessel under vacuum only is subject to their rules. You may even want to put a safety valve on the tank set at less than 15 psi.

For peace of mind regarding use of these vessels for your intended purpose, you might have a U stamp holder (or even a R stamp holder if they can perform alterations/calculations) perform design calculations on the vessels (if you have enough info on the materials and construction) to determine their Maximum Allowable External Working Pressure (MAEWP) for inormation only.