High Pressure Steam Boiler

[Deleted User]

We have a boiler inspector that wants us to test the reliefs on a high pressure steam boiler by jumping out the pressuretrols and taking the boiler up to 150 psi to see the reliefs blow. Has anybody else ever done this test?
We have done hydros and had reliefs bench tested, we also have had to lift the relifs at 80% of the boilers rating,
but have never done this before. This boiler is approx. 50 years old.

db_4

Whoaaa Nellie...

Mike,

Ive worked in the power / process industry for 28 years,
for the most part all PRV's are sent out to rebuild /
testing depots for maintenence.

Here's a link from another site;

http://www.eng-tips.com/viewthread.cfm?qid=15220

I'd ask the inspector "where" in your local mechanical code
that "onsite testing" ( via the boiler ) is a requirement,
or safe or smart to do.

Recertification every 3 years or so I can believe, doing
it inhouse without the proper equipment and safegaurds is,
in my view "not too safe"

Outside shops provide these services, I'd look for one
if the valve needs recertification.

( I did know of one that did live steam testing, they where
an ASME Code stamp shop )

Be Safe, db

Blackoakbob

capacity testing.....

we have been doing it like this for the past couple of years: Close off the non-return to the header,to isolate the boiler being tested from the load, the slowly raise the firing rate 'til the safety lifts and increase the rate to max fire and observe (nervously) that no increase in pressure is noted. Then shut down and observe relief valve seating. This really does two things it first checks the operation of the safety valves and second the actual input rate of the burner. When burners are tested and adjusted, once or twice a year, most of the correction for O2, CO2, and CO is done on the fuel side. This can and has lead to overfiring of boilers and in turn exceeding the rated safety valve capacity. I wouldn't recommend this ype of test on a boiler that was in less the "good" condition and only after having manually lifted the relief valves and observed proper mechanical operation. Also, be prepared to replace these very expensive valves as they often do not close tightly. A simpler and less stressfull way to check input capacity would be to clock the gas meter or check the gpm on the oil meter and leave the live testing of safety valves to the ASME CODE approved valve assembly company/supplier. I am not sure that this type of "live fire" testing is code required or insurance company required ( they are not looking for any claims) so I would discuss the need for it and the reason for the inspectors request. Best Regards.

Tony Conner_2

I...

... believe that there's a requirement now that calls for steam safety valves to actually be tested on steam, both for the set pressure, and capacity. (Valve rebuild shops used to use air for testing.) If you've got a big boiler, it can be hard to have enough steam in a shop to do the safety valves.

don_52

National Board Resource...

Gents,

This link will take you to an online .pdf which is
"hyperlinked" for online viewing.

http://edt.nationalboard.org/icons/printpdf/nb18/NB18ToC.pdf

This link will take you to a downloadable ".exe" (zip)
file of the same about 8meg.

Futher info on regs and specifics may reside at;

http://www.nationalboard.org

Regards, db