pressure vessel testing

Hi guys, i have made several air vessels, 300mm x 34mm x 28mm wp 200 bar

i have tried to get thes tested but have been knocked back several times,

how do i go about getting them tested, certed, etc.?

any help apreciated, thanks Garry.

For what purpose are these vessels?

What standard do they comply with?

Who did you enquire with?

Garry, if your cylinder holds under 500cc of air,under current uk laws it does not require testing, i have been making pcp airguns over 25 years,but i test each of my cylinders to a third above the working pressure,.i can assure you the vast majority of british pcps manufacturers dont test each rifle.

When i made my first cylinder i hydrostatically tested it, then i took it to Lloyds british, and got them to test it, to make sure what i was doing was safe and correct.

Hi Garry

Well cleared Shaun

In a former life I did lots of hydraulic as a norm 1.5 x wp (hydrostatic at various temperatures) testing on hp steam lines on power stations, refineries etc, however over the years some less than safe activities involving pneumatic testing world wide has caused a great deal of fear amongst companies, due to the explosive forces should ruptures occur, I myself have witnessed poorly methodized companies have some quite catastrophic equipment failures where only by the grace of god no serious injuries or fatalities have resulted, however a search on the net will show you that not all companies are so lucky and I'm sure your aware of ballistics and it's affects on people, the US military tent to undertake tests in with the vessel in large tank of water to limit the shock wave when failures occur.

The fittings, gauges and appropriate rated hoses can be attained from hydraulic suppliers who would probably make you up test rig which would be more than adequate for self testing, however the cert is a bit more complexed and would need to be witnessed by a competent person familiar with testing processes and acceptable outcomes and usage of test item.

If for PCP air rifles why not buy from air rifle makers as they have made bottles ready?

thanks guys for your replies,

i have made and tested these cylinders up to 400bar over night hydraulicaly and 300 bar pneumaticaly without failure

i think that would be adaquate, i still have one on my a/rifle for over a year now i would say that is a good test,

several people have asked me if i would supply them one but i was concerned about the laws.

It seems likely that in the UK the Pressure Equipment Regulations (UK enactment of the Pressure Equipment Directive) would apply (if supplying these for beyond your own use).

The classification of the vessel described by the OP when used for compressed air would be 'Sound Engineering Practice' (the lowest category) - there is no specific requirement to involve any third party in review/witnessing of either design or manufacture/testing for SEP items.

There are requirements regarding marking, and provision of adequate instructions.

A Technical File should be prepared to cover the design, materials used, inspection & test - this would be a significant part of the manufacturer's defence if an incident did occur.

PED generally expects a pressure test, but does accept (justified) alternatives.

Don't forget to consider the potential for fatigue failure in this application.

It might be worth having a look at **LINK**

Russell.

Russell - The Simple Pressure Vessel Directive relates to series produced welded vessels for use up to 30 bar, so is not applicable in this particular case.

Edited By David Jupp on 14/01/2016 09:52:03

As this pressure vessel is intended to be part of a weapon, it is exempt from PER. Still wants testing tho'

The exemption from PER is for items specifically designed and constructed for military purposes.

I'm honestly not clear if weapons automatically fall under this exemption, or if the exemption only covers use within the armed forces. Happy to be enlightened by those with specific knowledge.

Either way the approach required by PER would be a good place to start and isn't particularly onerous. I suspect materials certification/traceability might well be a stumbling block for some though.

I've just read schedule 1 which deals with exemptions, it doesn't mention military, just weapons. It might have been intended for the military, but it doesn't say so. The regulations for vessels of less than 250 bar.litres also differ from larger ones. This vessel is 36 bar.litres. It's all very clearly laid out in

**LINK**

another excellent publication from the HSE

We are obviously looking at different legislation - PER and PSSR.

I think pressure vessels or items that are pressurised under normal operation but are not covered by the PED due to exemptions are usually covered by other regulations. Boilers and gas turbine casings are examples.

Martin

thanks for all your replys guys. ive been checking the links& reading up,

as you can see it is a bit complicated and confusing, rules regulations conflicting, this is the problem, finding which rules apply to me.

Cheers Garry.

This is a very confusing area. My interest is as a small steam loco maker. Reference is still being made to the "3Bar/litre" rule which as far as I am able to establish,was revoked by the PSSR Regs 2000. This piece of legislation is most uncompromising and even Mamod models are caught by it. I did read somewhere that in view of the difficulties this would cause an exception was to be made for small models which would formerly have been included in the 3Bar/litre catchment. Has anyone anything definitive to add to this?

Mick

Mick,

I am not qualified to advise, but: The HSE guidance contains this fairly explicit statement:

MichaelG.

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Edit: Free download of PSSR 2000 available here.

Edited By Michael Gilligan on 15/01/2016 10:12:58

Edited By Michael Gilligan on 15/01/2016 10:25:07