Testing small gauge loco gas tanks.

[Les RileyParticipant @lesriley75593]

Our Club has been building a Gauge 1 and Garden gauge track for the last couple of years. We are almost ready to let folks use it. We are starting to get new members, and some old ones turning up with various locos that have not been tested for some time or have no provenance.

Boiler testing we can handle OK but the issue of gas tank tests has appeared. The tanks in question are commercial products but come with no paperwork because the engines were inherited. According to the suppliers info, they were tested at the factory to 500psi but we have no individual certs.

We now need to test these to 400PSI to issue a certificate for them.

The question is how? Do we test via the filler valve hole which is tiny or do we test them via the outlet pipe  by removing the isolating valve? Once we have filled it with water, how do we drain it out ready for use again?

Anyone have any experience of testing these engines please?

Les

[bernard towersParticipant @bernardtowers37738]

Doesn’t the boiler code say that commercially made ones are ready to use and only need to have a five yearly check. I think if you look at the Faq’s on gas tank testing it might be made clearer. I am in the process of making a gas tank for my steam boat at the moment to bring it up to current standards so I hope I have read the rules correctly.

[Les RileyParticipant @lesriley75593]

Our problem is that although the tanks are commercially made, they did not come with a test certificate like the rules say they should so we are back to square one as though they are new, untested tanks.

The code says the tanks must be tested to 400PSI initially and checked visually and with soap solution every 5 years.

I can’t find anything about whether to leave the filling valve in place or to blank it off.

[BazyleParticipant @bazyle]

I’m not saying this is the code but Valves etc are not part of the tank so not under test. They might not be able to take the stress of the hydraulic test however you might want to confirm their integrity at something above operational levels as even a small ‘drip’ can be problematic especially with ‘heavy’ butane.

Which club? We at St Albans commissioned our G1 & G0 track a couple of years ago and it is proving popular.

[Bazyle]

On Bazyle Said:

I’m not saying this is the code but Valves etc are not part of the tank so not under test. They might not be able to take the stress of the hydraulic test however you might want to confirm their integrity at something above operational levels as even a small ‘drip’ can be problematic especially with ‘heavy’ butane.

Which club? We at St Albans commissioned our G1 & G0 track a couple of years ago and it is proving popular.

That is what I would have thought. The valve gets a check with the soap solution afterwards when you fill it with gas.

We are South Cheshire, based in Nantwich. We are hoping our new track will become popular. We have had lots of interest but not many new members yet. We think folks are waiting for all the heavy work to be done!

 

[bernard towersParticipant @bernardtowers37738]

Surely if they are commercially made tanks they came with a cert, the fact that you dont have it i admit is not good but is it ok to test again at the full pressure. we do not do this to boilers.. Also if the tanks are commercial they should be marked with the relevant info.

[bernard towers]

On bernard towers Said:

Surely if they are commercially made tanks they came with a cert, the fact that you dont have it i admit is not good but is it ok to test again at the full pressure. we do not do this to boilers.. Also if the tanks are commercial they should be marked with the relevant info.

According to the gas tank code, if you have no provenance with the tank, it must be re-tested.

In this particular case we have now discovered the original supplier and found instructions which show a serial number hidden from view when fitted to the loco. We are going to check this out and just maybe get a replacement cert. Otherwise it will be a re-test.

[bernard towersParticipant @bernardtowers37738]

I cannot find in the test code where it says the comm tank has to have a cert, it just says comm made and offered for sale. Certification is mentioned later but doesn’t say its mandatory to have one.

[Les RileyParticipant @lesriley75593]

Bernard, have a look at para 9.7 here:-

Boiler Test Code 2018 – Volume 3 LPG Tanks below 250ml

[bernard towersParticipant @bernardtowers37738]

Yes i get it Les but why is it ok to hydraulically test these to the max more than once when they have not had any structural alterations? Bit of a can of worms i think.

[duncan webster 1Participant @duncanwebster1]

I think if a boiler came for test with no paperwork it would have to be tested to twice WP. Otherwise how do you know it has ever been tested?

There should still be a small factor of safety against yield at test pressure, if it has held once, it will hold again. Doing it time and time again would not be good, you could get low cycle fatigue, but twice shouldn’t be an issue.

 

[noel shelleyParticipant @noelshelley55608]

This thread illustrates the importance of keeping ALL paperwork for any pressure vessel safe and with the vessel to which it applies. It matters not whether the vessel is commercially made & marked or not – with out the paperwork it should not be used and must be certified as a new unit. Since safety factors of 6, 8, or even10 are used in designing boilers a second X2 WP test will do no harm – if it does then the vessel was unfit for use anyway. To test to twice working is not “The Max” one could go to 3 or4 times WP, or even test one unit to destruction to show that the calculations were sound. Volume 3 of the 2018 code lays down the rules and procedure, it is clear that a tank may have a second test to 2xWp if altered or repaired. This code ONLY applies to vessels made of copper or brass and no greater capacity than 250ml. Noel.

[noel shelley]

On noel shelley Said:

This thread illustrates the importance of keeping ALL paperwork for any pressure vessel safe and with the vessel to which it applies.

I quite agree Noel. One of the two engines presented for test had it’s cert tucked in the box, so it is fine but the other didn’t so we are at square one.

Sadly these engines came to our club member from a deceased friend so we are checking all avenues.

[noel shelleyParticipant @noelshelley55608]

Les, is testing them a problem ? You have to conduct a hydraulic shell test, can I take it the gas tanks are detachable from the loco ? IF so them remove and plug all holes bar one and make up an adapter  to fit this hole so that it can be connected to your test pump – proceed as for a boiler. Test pressure to be 400PSI.  The safeguard test requires that the tank has the fittings added then filled with gas, raised to a temp of 20C and checked for leaks using soapy water or by immersion in a tank of water. Safety checks must be carried out every 5 years or less in the form of a leak test. As I have said V3 of the 2018 code tells all. Good luck. Noel.

[Les RileyParticipant @lesriley75593]

Our member has now removed the tank and we will test it from scratch. Had to hunt around for a 400psi gauge but we now have one!

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