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Live Steam boiler legality and Boilermaker Questions

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James Keen23/01/2018 02:16:25
1 forum posts


I have a few questions that I would like your help with which all involve live steam boilers as I am not entirely familiar with the law surrounding them and I cannot seem to find the answers to my questions clearly written anywhere (unless I'm simply being blind).

Essentially I am in the market for a new vertical boiler that is ready to use in (3-5" diameter, this boiler is to be used in a stationary setup.

At first It will simply be a home based Model however in the future I would like to possibly join a club and take it to model engineering shows. With the further possibility of marketing my design along with a boiler bought from a boilermaker.

My questions are:

1) Is there a requirement that all newly produced boilers have a CE marking?

2) What legislation affects Live steam boilers in this size range (3-5"

One further question that I hope I am allowed to ask (remove if you must)

Has anybody on here had any dealings with Pendle Steam Boilers? and would you would recommend them?

I question the CE markings as I have seen most Model boilers on the market today are being listed as having a CE marking whereas Pendle Steam Boilers does not?

Thank you for your help.

David Jupp23/01/2018 08:34:42
716 forum posts
17 photos

Requirement for CE marking depends on size. If volume is less than 2 litres the steam generator would fall into 'Sound Engineering Practice' in which case it must NOT be CE marked.

Above 2 litres CE marking is required if the item is 'placed on the market'.

Information on the UK implementation of the Pressure Equipment Directive is available at


The link on that page to the full guidelines wasn't working when I tried to follow it, so I haven't posted it.

If the safety valves are designed specifically for the steam generator, they follow the category of it - otherwise they are Safety Devices and are placed in the highest category and are subject to CE marking.

fizzy23/01/2018 09:10:00
1690 forum posts
114 photos

Hi James, the information provided by David id spot on. I dont think anyone on this forum has one of my boilers but to date I have never had a single complaint and would be very happy to put you in touch with an array of very happy customers. Check out an independant test by Roy Burton on Youtube, he has one of my Kingdon boilers, Ive got three to complete in the next few days **LINK**

Edited By JasonB on 23/01/2018 13:12:19

Nigel Bennett23/01/2018 14:31:43
327 forum posts
11 photos

It's not simply a case of volume of the boiler - it's the product of volume and working pressure. My Clayton steam wagon boiler, for example is only about 1 litre, but its working pressure is 5,5Bar. 5,5 Bar litres brings it well within the requirements for CE marking. Even my Tom Rolt in 3.1/2"G is below 2 litres in volume.

James, I'd join a club now. Go along to one of your local clubs as a visitor and see what they're about. They should welcome you with open arms - and you'll have a source of good information to tap. Aske their boiler inspector(s) for advice.

David Jupp23/01/2018 14:59:19
716 forum posts
17 photos

If you refer to Chart 5 - Steam Generators, of PED that shows no pressure limit if V < 2 litres.

There is a special exception for pressure cookers, which are treated more strictly.

The lowest values for product PS.V is given in Chart 1 (for nasty gases) and is 25 bar.litres

I agree with Nigel, that some of the boundaries on the charts (including Chart 5) are set by the product PS.V

If an any doubt refer to the Charts yourself


Technically those notes are outdated, though easier to follow than the full text of the directive. The charts included are still correct, even for the updated 2014 version of the directive (effective 2016).

IanT23/01/2018 15:36:50
1435 forum posts
141 photos


My understanding is that the CE marking is simply one of whether the pressure vessel is above or below 2 litres (e.g. simply volume). So David is correct in his statement.

This confusion arises I believe because of the use of 3 Bar Litre as being the boundary between a "small" (< 3 BL) and "large" (>3BL) boilers as defined in the current 'Green' (soon to be 'Orange' ) book used by Southern Fed, NAME and others when boiler testing/inspecting.

A new (commercial) boiler should therefore be CE marked if above 2 Litres but NOT marked if below. However, you should also received paperwork from the manufacturer to demonstrate that a 'shell' (x 2 working pressure) test has been undertaken by them - and that the materials used are traceable and suitable.




Edited By IanT on 23/01/2018 15:43:57

Neil Wyatt23/01/2018 15:51:59
17344 forum posts
690 photos
77 articles
Posted by Nigel Bennett on 23/01/2018 14:31:43:

It's not simply a case of volume of the boiler - it's the product of volume and working pressure. My Clayton steam wagon boiler, for example is only about 1 litre, but its working pressure is 5,5Bar. 5,5 Bar litres brings it well within the requirements for CE marking. Even my Tom Rolt in 3.1/2"G is below 2 litres in volume.

That was the situation, but it was simplified a few years ago.


Neil Wyatt23/01/2018 17:26:19
17344 forum posts
690 photos
77 articles

I was mis-remembering - the situation applies to insurance limits and requirements for pressure testing (not CE marking), where the limit was raised from 1.5 to 3 bar-litres.

Full story by Richard Simpson, from our companion site

Boiler Room

Part Ten: Boiler Testing

RICHARD SIMPSON’s series on model steam plants

<excerpt - see link above for the full article>

A bit of history

Prior to 1st January 2006, all relevant bodies concerned with model boat steam plants such as insurance companies, clubs, local councils and even the Health and Safety Executive, had their own set of rules. This was all very difficult to understand and comply with, thus putting a lot of people off this sector of our hobby. A side-effect of this was that there were some who simply ignored the rules in the knowledge that often nobody really knew what was going on, and so no one could really hold them accountable!
As of the 1st January 2006 these organisations all got their heads together and declared a set of rules and regulations for model boilers. These rules have been accepted by the Health and Safety Executive, most of the big insurance providers and most modelling organisations, so it is now far easier for everyone to know just what the rules are and therefore who is not complying with them. These rules were compiled into a single book, now known as the ‘Blue Book’, which was accepted and adopted by many organisations except the Model Power Boat Association (MPBA), who maintain their own set of rules which can be seen on the MPBA website under ‘Technical Notes’.

The unfortunate bottom line with the ‘Blue Book’ rules as of January 2006, was the 1.5 bar-litre requirement, which basically stated that anything above this level required regular pressure testing.

The bar-litre requirement of the Blue Book

If you take the capacity of your boiler as the total internal volume in litres and multiply it by the working pressure in bar as stated by the manufacturer, you will determine the bar-litre figure. For example, a boiler of 500ml capacity with a working pressure of 5 bar is a 2.5 bar-litre boiler.
So, a limit of 1.5 bar-litres unfortunately meant that only Mamod and Wilesco type or other ‘toy’ boilers were exempt, so the vast majority of model boat boilers required pressure testing on a regular basis.

However in 2007, pressure (pun there!) exerted resulted in a reassessment of the requirements and the bar-litre rule was reset to 3.0 bar-litres, which now meant that about 80 to 90% of model boat boilers were below this level. Consequently if your boiler is less than the 3 bar-litre limit you are exempt from the pressure testing regulations. However, it is still recommended that safety valves are tested at least once every 12 months and the boiler and pipe work installation should also be checked at least every 12 months or so. This is not to say however that all insurance companies accept these standards and even some clubs have their own rules for their steam members, so it is still not quite as cut and dried as it may seem. Also of course, any event run under the auspices of the MPBA requires you to comply with their certification process, even though you may be fully certificated under the ‘Blue Book’. The MPBA technical papers on their website as of May 2011 ( also state that:

‘In addition to official MPBA certificates, those issued by the Northern Association of Model Engineers, the Southern Federation of Model Engineering societies and other recognised bodies, including those not residual in the United Kingdom, will be acceptable, providing their test methods and standards are similar to those of the MPBA’.
Bazyle23/01/2018 17:49:08
4989 forum posts
198 photos

It is Neil's last paragraph that is important. Forget government websites and boilermaker's opinions if your boiler is not to become the equivalent of scrap metal it must meet the interpretation of all the rules as laid down by a Federation or MPBA etc otherwise you will never be able to use it at a public meeting or sell it on to another modeller. So join a club and speak to their inspectors an they will tell you what paperwork they need from the commercial builder. If in any doubt don't buy.

IanT23/01/2018 20:30:24
1435 forum posts
141 photos

Mmmn - trying to post something that Word says is only 448 chars - but this site thinks is 1600 chars too long...


Edited By IanT on 23/01/2018 20:35:48

IanT23/01/2018 20:51:50
1435 forum posts
141 photos
OK - Let's try again James.
1) Is there a requirement that all newly produced boilers have a CE marking?

Only if that boiler is commercially produced and has a total volume of 2 Litres or more - otherwise it should NOT be marked.
Should you take a CE marked boiler to a Boiler Inspector - he will apply this guidance:

"A Boiler Inspector shall check that any CE Markings (where required by the Pressure Equipment Regulations 1999 No 2001 and The Pressure Equipment (Amendment) Regulation 2002 N0 1267). Boilers built commercially after 30 May 2002 which do not bear the appropriate CE marking shall not be tested" [Green Book - Revised Edition 2012) - Paragraph 6.4]
2) What legislation affects Live steam boilers in this size range (3-5" )
"Legal requirements, such as the Pressure Systems Safety Regulations 2000 (PSSR), do not normally apply to persons operating pressure equipment as a hobby activity. However the H&SE considers it good practice for persons using such equipment to provide the same level of health and safety protection as they would if they were duty holders under the regulations. To aid this process the principles of PSSR have been followed in drafting this document, which has been prepared after consultation with... (too many organisations to type here) " Quoted from the current Green Book - Para 1.2
3) "With the further possibility of marketing my design along with a boiler bought from a boilermaker."
You seem to be suggesting that you would like to sell your own boiler 'design' (or finished boiler?). A "design" (for others to build privately) would fall under Section 5 in the Green Book titled "Design Verification" and if not previously published (e.g. well proven ) would need to have clear drawings, adequate strength (by calculation) and a clearly stated working pressure - for the Boiler Inspector to examine and check.
I have no idea of what would be required to obtain a 'CE' mark - as that lies outside of a Boiler Inspectors remit.
Finally - as Bazyle has already stated, you do not need any boiler certification to use a boiler privately - although you will need the appropriate documentation should you wish to attend any public event (not because of legislation - but because of insurance requirements). In my view it makes great sense to regularly inspect any boiler in use (even privately) - as I assume that your personal safety and that of your family and friends is also important to you.

The current 'Green' book is about to be replaced by a new revision (the 'Orange' Book) which will probably be released in March 2018.

I hope this helps.
PS Solved the 'paste' problem by using Notepad to strip out any invisible formatting ...  seemed to work.

Edited By IanT on 23/01/2018 20:57:27

richardandtracy23/01/2018 21:08:31
938 forum posts
10 photos

Interesting. The last time I looked, those very regulations (or maybe their predecessors, but I don't think so due to the dates) specifically excluded fired boilers from their scope. Had to go into them very thoroughly to design & build a container for a Mars probe (Beagle 2) so it could cover a cocktail of small hazards for air transport. The only way to guarantee to get it approved quickly for flights over Europe to the launch site was to make a pressure vessel that would contain all hazards if everything failed catastrophically at the same time.

It was a while ago, but the regs seem to have familiar dates - but I wasn't looking at them with regard to a steam boiler at the time.



IanT23/01/2018 22:27:46
1435 forum posts
141 photos

Apologies - in my quote from the Green Book above - paragraph 6.4 somehow got corrupted (probably in my cutting and pasting too and fro to find the reason it wouldn't post).

It should correctly read;

6.4 The Inspector shall check that in the case of commercially made boilers these are CE marked (where required by The Pressure Equipment Regulations etc ........ )

Hope that makes more sense...




Edited By IanT on 23/01/2018 22:29:37

fizzy29/01/2018 19:35:12
1690 forum posts
114 photos

For anyone who likes looking at photos of stationary or marine model boilers ive uploaded some photos onto my profile.

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