Boiler certificates

Basically, why was 10 years chosen as the optimum length? What restrictions are there (e.g. mileage, no. steamings) which might mean it runs less than 10 years and similarly what factors are considered when a certificate is extended beyond 10 years?

 

I am by a very long way no expert, but I seem to remember being told that for insurance purposes if you wanted to stretch it to the limit the so called annual inspection could run for 14 months and you are allowed 10 of these before you needed to start ripping things apart. You could therefore get a boiler to live for just under 12 years. Perhaps any insurance inspectors out there could clarify the point?

 

Until relatively recently there was no legislation governing examinations of locomotives used on railways and they adopted their own maintenance and examination regime. Boilers in factories were a different matter and they came under the Factories Act. This included any steam locomotive in a factory (and this would include places such as Crewe works because they were regarded as 'factories'). The Factories Act required that no part of a boiler should go unexposed for more than 10 years so all the brickwork, etc on a Lancashire boiler had to be removed as did the cladding on a locomotive. It also requird a hydraulic test to 1.5 times working pressure at 6 years and 10 years. With the growth of the Heritage Railway movement this anomaly was of concern to HMRI as there was no legal requirement to carry out routine examinations of steam locomotives operating on railways. This was well before the Health & Safety at Work Act strarted to bite, with all the later regulations. HMRI therefore produced a guidance note - PM18 I think it was - later superseded by HSG29 on steam locomotive boilers. They took exisitng BR practise into account, along with the Factories Act. BR used to strip boilers at much lesser intervals than 10 years because of their working conditions. HMRI produced a hybrid scheme of examination which suggested that loco boilers should go for 7 years without external examination and allow the Boiler Inspector discretion to give extension up to 10 years. The introduction of thePressure Systems and Transportable Gas Containers Regulations in 1989 (subsequently replaced by the Pressure Systems regulations 2000) removed this anomaly and introduced the concept of a 'Written Scheme' and it is this scheme that lays down the examination requirements. The Written Scheme is approved by the Competent Person (Boiler Inspector in traditional parlance) and it is usual for him to be employed by an Insurance Company. However, legally, you can have your own Competent Person and specify whatever examination routine you wish, so long as it is suitable and sufficient and the Competent Person approves it. The HSC issues an 'Approved Code of Practice' for Pressure Systems and compliance with this is deemed to be compliance with the Regulations. The Code states that: 'When deciding on the periodicity between examinations, the aim should be to ensure that sufficient examinations are carried out to identify at an early stage any deterioration or malfunction which is likely to affect the safe operation....'

There is a strong argument that boilers deteriorate just as quickly if they are not in use, unless rigorous procedures are put in place to prevent internal corrosion, so lack of use is not likely to be good grounds for an extension. The products of combustion and the moisture in the atmosphere combine to produce chemicals that attack the base materials and electrolytic corrosion will happen at steel copper interfaces. It basically just depends on the deterioration that the Inspector can see and a judgement on what will have happened to the bits he can't see, together with the willingnes of Head Office to agree to the increased risk.

The approach to examinations has changed significantly over the years. When I first got involved the Boiler Inspectors weren't bothered about removing boiler tubes to enable a full internal examination and it was common for brass or copper tubes to remain in situ for 20-30 years (Steel never lasted that long but could certainly do more than 10 years!) Even today, on gas or oil fired land boilers, the tubes are not generally removed unless they need replacing and can easily reach 30 years. Hydraulic tests were always to 1.5 times working pressure and corrosion was generally acceptable up to 50% wastage. Any cracking in a copper firebox would, unless it was right through the plate, merely warrant the comment 'to be kept under observation' on the report, as would grooving at foundation ring level where it was commonplace to just put a run of weld along the outside to cure the leakage.

Whilst we're talking about boilers, there is no standard for steam locomotive boilers and never has been. Loco builders evolved their own standards, usually along the lines of 'we always made it this size; the last time we reduced the size, we had problems.' There is a standard for welded boilers (BS2790), a lot of which can be applied to locomotive boilers, whether riveted or not but to apply it retrospectively is a recipe for disaster. As an example there is a section on girder stays in BS2790 but most loco boilers with these would fail to met this standard by a considerable margin. Tubeplate design is also a non-compliant area for exisitng boilers. This is one of the major problems when designing a new all welded boiler and why people generally fight shy of doing so.

 

Further to my original query, a mainline certificate runs for 7 years, is this automatically the first 7 years of a certificate, or can it run two years then be mainline certified for 7 years?

 

Seven years from the date of the first sucessfull complete steam test, following hydraulic test.

 

So, for arguments sake, an engine first steamed in 2004 and was taken mainline next year for the first time could only run for 3 years (until 2011) without more work being done to it

 

Provided that it passes 'muster', yes.

 

what about new build boilers im going to be building one in 7.25 and would like to know the ins and outs as im scaling up a published degsign by 1.45 to get the right one allso does anyone know if i could build a copper one myself using silver solder and for the cheaper version does antone know of a coded welder whom could weld me up a few seams i can weld but im not coded

 

Easiest response is to talk to your local ME society (and become a member).

Stephen

 

i will be doing i was thinking of a stainless steel boiler too

 

Rough-shunter was you thinking of making the stainless boiler steamable? or just for static display?

As I believe (I'll have to double check with my clubs boiler inspecters) Stainless steel boilers in miniature are not allowed to be steamed.

 

on the continent it is the norm for stainless boilers to be used i know that the 7 1/4 socity is looking to get them allowed.

 

I didn't know that, but I thought that as it is a softer material it will start to do things that normal steel wouldn't do,

Like I said I'll have to double check though (it's not that I don't believe you rough-shunter but it's bettter to be on the side of cution)

 

I believe rough shunter is correct - the majority of uk club insurance will only insure copper and steel boilers, however stainless boilers are regularly used in the continent.

Whatever boiler material you go for, it is the boiler management that cause failures (eg not washing the boiler out).

Stephen

 

As Jordans Local Club Boiler Inspector, and a designer of Stainless Pressure Vessels here goes!

Stainless boilers are widely available and used on the continent, and can be used here, if you can get an independant insurance inspector to inspect them. Current Northern and Southern fed rules mean that a club inspector can not test them. This is daft as testing them is no different to a copper or steel one! The big difference is in the manufacture and as any pressure vessel manufactured for sale must conform to PED, it will be considered "fit for purpose"

Craig

 

o hello craig me and marcus disscussed stainless boilers yesterday on the way home and he said asloong as it was CE marked ect it could be used just not examined by the club reminds me i need to talk to you about boilers for dougal

 

Yes it can be used, but it must have an Boiler inspection certificate to prove insurance, so you would need to find someone who could test Stainless and issue one, which is possible but expensive!