Procedure for Hydrostatically Testing Pressure Vessel

[sraesttam]

I recently purchased a 240 gallon pressure vessel that I plan to utilize as a compressed air storage receiver in my shop. The vessel was manufactured in 2002 and is rated for 200 PSI MAWP @ 400 degrees F. The vessel is designed to be installed vertically. I plan to operate this vessel at 175 psig. I would like to hydrotest this vessel to ensure that it can be operated safely. I am doing this solely for peace of mind and therefore I do not need any type of certification. A picture of the vessel nameplate is uploaded.

I am planning to leave the vessel on the trailer horizontally, fill it all of the way up with water using a garden hose, pressure up to 30 PSI using a hydrostatic test pump, hold the pressure for 5 minutes, pressure up to 300 PSI (1.5 x MAWP) using a hydrostatic test pump, hold the pressure for 5 minutes, bleed off pressure, drain, set in place, and then put into service.

Do you have any recommendations regarding my procedure? Is there anything that I am forgetting?

I have no experience hydrostatically testing pressure vessels. I own a 10,000 psi hydrostatic test pump that I use for pressure testing oilfield equipment that I will be utilizing for this.


Vessel Nameplate

 

[Dhurjati Sen]

Dear sraesttam,

The following is required for your peace of mind.

1. Carry out a visual inspection of the vessel internally if possible, else externally.

2. Look for physical damage, dents etc.

3. Carry out LPI of all nozzles.

4. Use potable water with a chloride content less than 250 ppm for hydro-test. Else dry the vessel completely using hot air, etc. after hydro-test and complete drain out of water.

5. Install a pressure relief valve on the discharge of the hydro-test pump. Set it at 110% of test pressure, i.e. 330 psi.

6. Use original gaskets.

7. The test presure is to be held for at least 10 minutes or as long as you need to complete the inspection.

Regards.



DHURJATI SEN

https://www.nace.org/people/dhurjatisen

 

[r6155]

First you need
1)Documentation: drawings, calculations, material test reports, etc.
2)Check actual thickness of pressure parts
3)See API 510, pressure test may be waived

Regards
r6155

 

[EdStainless]

The first thing that I would do is grab a fiberscope and look at the inside , bottom welds.
If they look heavily rusted then I would clean the tank before testing.
If after cleaning they look pitted then I would look for another tank.
Your procedure is sound.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[MJCronin]

If the vessel has a MAWP of 200 psig and you intend to operate it below that pressure, why are you performing this test ?

Air receivers are notorious for internal corrosion as drainage of water always becomes a problem. Put your time, effort and money into assuring that you will not be operating a corroded vessel ........IMHO

MJCronin
Sr. Process Engineer

 

[LittleInch]

Difficult to see without some dimensions / pictures etc, but I would be a little wary of doing this with the vessel on its side. This could concentrate stresses if not completely flat and is much better if you can lift it up. apart from anything else where are the connection points? There is often one in the top dome so it's easy to completely vent the vessel.

Weight of this full of water will be a lot more than normal so the legs might need some support or re-inforcement.

Pressure tests often go up in stages 25/50/75/100%.

A 16 year old vessel eh? Agree totally with above - a very good internal check for corrosion is a primary requirement before you start.

External UT might be required in some locations.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[sraesttam]

All, thank you for your recommendations.
Dhurjati Sen:I will carry out a visual inspection, look for damage, and will be using city treated drinking water for the testing. I will hold the max pressure for 10 minutes.

r6155: Thanks for the information.

EdStainless: I will see about using a scope to visually inspect the bottom welds and bottom part of the vessel. Maybe this is the excuse I need to buy a scope.


MJCronin: I am performing the test based on two assumptions (please let me know if they are incorrect). 1) I would rather have a vessel fail while filled with water than when filled with air. 2) If the vessel passes a hydrotest at 1.5 x MAWP, then operating at 0.875 x MAWP should be fine for a couple of years as long as the tank does not experience major corrosion. I am planning to install an autodrain on this vessel to ensure that it stays as dry as possible. I am also considering installing a refrigerated air dryer before this tank.

LittleInch: The vessel is approximately 3 feet in diameter by 8 feet tall. The vessel will be holding approximately 240 gallons / 2000 pounds of water. I do not believe that there is an opening on the top of the vessel. (I have not had a chance to actually go inspect this yet.) I think that there is one opening on the bottom and four on the shell. There are 2 x 2 inch openings on the "east" and "west" side of the tank. I am planning to lay the vessel down where it is completely flat and not rest on any tank openings, plugs, etc. If it test upright, I think that I will still have a couple of foot of air "head" at the top of the tank, hence my thought to keep it on its side so that the tank will be entirely full of water. I will stage up the test in 25/50/75/100% increments.

It will probably be a couple of months before I get around to this, but I will post the results of the test.

Thank you again.

 

[zeusfaber]

1) I would rather have a vessel fail while filled with water than when filled with air.

Absolutely. We've burst vessels both ways, and it's the difference between watching a concrete megablock being tossed thirty feet into the air or wrecking the blockhouse completely and picking large cylinder fragments up off the beach three quarters of a mile away.

 

[r6155]

sraesttam, you are working in a wrong way

1)Hydrostatic pressure test for a PV made in year 2002 is 1.3 x MAWP ( not 1.5)
2)Water temperature during test shall be controlled
3)Be careful of notch toughness of pressure components before pressure test
4)Be careful: in nameplate you can see RT-NO
5)Visual inspection shall be at MAWP after pressure test 1.3 x MAWP
6)More informaion in ASME PCC-2 Repair of Pressure Equipment and Piping
7)There is an opening on the top of the PV.

Regards
r6155

 

[SnTMan]

Just noticed the NB #. sraesttam if you will supply this number to the National Board they should, for a small fee, be able to supply you with the U-1, telling you more about what you've got.


The problem with sloppy work is that the supply FAR EXCEEDS the demand