View Full Version : Valve failure in Ammonia Systems.

01-06-2012, 05:42 PM
Hi Guys.

Follow the link for free guidance as issued by the I.O.R.
Some may well recognise the Valves in question.
Worth reading anyway.

http://www.ior.org.uk/app/images/pdf/GN 22 - update May 2012.pdf


03-06-2012, 10:10 AM
Hi, Grizzly:)

Thanks for sharing this document ....

this is a kind of warning to all serviceman (unfortunately only to those that read this article), but all sounds like article of public relation spokesman, to cover somebody's back ....

I'm sorry about injured serviceman, but in my personal opinion, he was not wearing complete PPE or he was not skilled enough to perform that job .... old ammonia plant, small valve on liquid pipe probably with visible rust/corrosion, installed "maybe" in very wet ambient ... enough to be extra careful

... furthermore there is not mentioned valve manufacturer !?! neither the cross section of that kind of valve with exact marks of questioned valve parts, sounds like complete construction and design of that valve is not good .... to much grey zones (except part with conclusions) in that article, at least for me ....

Best regards, Josip :)

03-06-2012, 11:36 AM
More than a little harsh Josip.
I believe I know the company involved and their engineer are usually very proficient.

It is easy to criticise after the event.

In this guys defence I have worked with this type of kit for years and have never known the failure that occurred happen before.
This style of valve is very common and many of the plants that I have or do work on have been as old or even older.
I agree the report is worded in a "Guarded fashion and the engineer may have contributed.
But is this not what H&S love to do, after all they are professional blame apportioners.
Lots of power and no liability

They even hide behind their job titles nowadays. IE original job description was H&S manager.
The clever guys are now known as Specialists.
Because I am led to believe specialist cannot be held responsible whereas Manager can, at least in the eyes of the law.

I know of one case were a very proficient engineer vented off a liquid level sight glass, having isolated correctly etc with a second site engineer in attendance.
Once satisfied that all had balanced out the vent line was removed from the drain port at the bottom of the liquid level sight glass. With the port left open to further vent.

He and the other engineer continued on with other works when sometime later he realised he Had left his adjustable spanner by the l/l sight glass.
Whilst reaching down to pick up the spanner the previously opened vented port spat out oil and ammonia all over his overall covered arm.
Resulting in frost burns to his lower arm.
The damage was only slight resulting in the engineer being fit enough to complete his repairs.
He did end up having his arm dressed at hospital.

Only later when H&S got involved did the blame start flying and guess who got the blame.

03-06-2012, 08:06 PM
Hi Grizzly,

this valve is an AWA valve, more than 3 accidents occured. On the picture you can see one broken during a job done by 2 very good ingeneers. no one was injured as they were wearing their EPI ( ammonia mask, gloves etc). this valve is not in poor condition, it's 1 year old.9005GEA made also an advertisement about this kind of valve and the risk involved. this valve is on my desk.

monkey spanners
03-06-2012, 09:21 PM
Think i read that article as i'm a IOR member and they send out info like this every now and then.

Seems to me if you can't undo a plastic cap (16Nm if memory serves) without another spanner on the body, the valve is not fit for purpose....

If you work out the Lbs per sq inch and the area of the valve i bet the loading would be over 16Nm. 500psi over 1" pipe cross sectional area is nearly 1/4 ton trying to pull the valve apart, makes you think when you are leaning over cylinder heads etc....