New boiler testing regulations.

Once again, that time of the year is approaching! Loco owners everywhere will soon be queuing up for their regular boiler test.

You probably know that this year (from January 2006), the rules have changed. Existing certificates are valid up to the expiry date shown. Then they must be tested as described below.

This is a summary of some of the changes and how we test previously tested boilers at Coate. The tests depend on the size of the boiler, the material (copper or mild steel) and whether it is new or has been previously tested. We will not test stainless steel boilers.

There are currently three authorised Boiler Testers for the club, Reg Barrett, Mike Fox and Dave Jenner, and we will test in accordance with the SFMES “The Examination & Testing of Miniature Steam Boilers”, a copy of which is kept in the Clubhouse.

We do our best to accommodate people, but obviously that if you turn up on spec; a tester is not always available. Even with advance arrangements, things don't always go according to plan! You should understand that you are responsible for preparing the boiler, making the connections, etc., not the Boiler Tester.

The Tester has the right to decide how he is going to conduct the test - no use arguing, the Boiler Tester’s decision is final - and all tests must be witnessed by a Club member (not the owner or builder).

Bar-litres

This is the water/steam volume of the boiler (in litres) multiplied by the working pressure in bars (1 bar = 14.5 psi). This must be stated on the Test Certificate. So get that measuring jug out now!

Boilers below 1.5 bar-litres do not need to be tested (but we will be happy to do so). We will normally test up to 500 bar-litres and, exceptionally, up to 1100 bar-litres.

Examination

The new rules place more emphasis on visual examinations than the previous rules did. In particular, the Inspector may require the cladding to be taken off or the boiler removed from the frames, not more often than 10 years, to check the condition of the outside. For steel boilers above 500 bar-litres, the frequency is reduced to seven years.

Don’t forget to bring a torch and inspection mirror for the Tester to use to examine inside the smoke box and firebox.

The Hydraulic Test

For the test, the safety valves should be removed and the bush plugged off. It is not a good idea to screw down the safety valve, the setting is then lost. The club pressure gauge must be connected, it has a 1/4" x 40 female fitting, so you must provide the male connection on the boiler. It’s up to you to provide the correct connections; the Club’s fittings always seem to go walkies! You will also need to connect the Club pump, using a similar fitting, unless there is one already on the loco.

The reading of the boiler pressure gauge will be checked against the test gauge during this test. In particular, the working pressure of the boiler must be marked, as indicated by the test gauge.

The test pressure shall be 1.5 x the working pressure, held for a minimum of ten minutes.

The Steam Test

There are three things to check, that: -
at least two methods of feeding water to the boiler are working
the water gauge gauge(s) can be blown down and can recover its level without delay
the safety valves are correctly set and can relieve the boiler pressure with the blower fully open (a pressure build-up of not more than 10% is allowed).

This part of the test arguably causes most failures and is one that owners can easily check for themselves beforehand.

Frequency of Examination

The hydraulic test is required every four years for copper boilers, two years for steel boilers.

The cold examination and steam test is required at least every fourteen months. Note that this really means annually, it just gives a little latitude on the re-test date.

The above applies to boilers, which have previously been tested. If you are building or buying a new boiler, the rules are different. The details are given in the Rule Book. There is also advice on boiler maintenance. If you’re not sure what’s required, have a read and feel free to ask about anything you don’t understand.

Finally, the style of Certificate has changed. We have bought enough of the new Certificates to keep us going for some time. Don’t forget to bring the old Certificate to the test, though.