Fire extinguisher maintenance

[lingmoor]

I have just spoken with a fire extinguisher maintenance engineer who has told me he will not do a 5 yearly water discharge test on extinguishers with plastic caps (the bit that screws off!)as one exploded in the past because it became brittle. He said the British Standard was changed to say that metal caps should be used

anyone else heard of this?

[Tom Sutton]

Yes its in BS 5306-3:2009 for extended service. It says if fitted with a plastic headcap it should be fitted with a new headcap before test.
Also if it show signs of UV degradation and if it is coated or painted over which could hide any defects it should be replaced.

It includes plastic headcaps retained by a metal collar but not not a metal headcap which has a plastic shroud.

You will have to wait for AnthonyB to respond about replacing with metal headcaps as far as I can see it just says new headcaps.

Check out http://fire.org.uk/forum/index.php?topic=3903.0

[lingmoor]

Thanks for that Tom...tis appreciated.

[AnthonyB]

As Tom says.

Really they should change the plastic head, however for some makes they are no longer manufactured.

Thomas Glover Series 2000 and any cartridge extinguisher using the Ceo-Deux headcap (Allied Safety, TOTAL, Gloria/Kidde FPS) still have spares.

Other stuff like TG S2000 small powders, Chubb pre 1992 stuff, etc is discontinued.

Admittedly with the price of new extinguishers to the trade it is quicker, cheaper and simpler to put a new unit in on an exchange basis.

[lingmoor]

Thank you Anthony

[Tadees]

What are the signs of degradation and what are the chances of the end user being injured by a plastic operating valve that has been subject to UV degradation?

[lingmoor]

There are no signs of degradation. He says he advises the client that they should be changed... but wont do a discharge test unless it is changed

He quotes BS 5306-3-2009 (which I now have)  under Extended Service Procedures...

Action 1 (inspection prior to discharge)

 "If a plastic headcap is coated in such a way as to disguise deterioration (eg painting) replace with a new headcap before action 2" (which is discharge)...

Action 5

" Return the extinguisher to operational condition. if the extinguisher was fitted with a plastic headcap, it should be fitted with a new headcap, if this has not already been fitted in Action 1"

So why does the BS waffle about painted plastic headcaps in Action 1 if you have to change it anyway in Action 5?

[AnthonyB]

The risks are genuine as engineers have been seriously injured test discharging plastic headed extinguishers.

I've had plastic spray lances fly off the post 1997 S2000 Foam extinguishers due to degradation.

Because plastic heads are most common on cartridge extinguishers there will always be someone in the close vicinity if there is going to be a failure as it will break upon activation when the pressure jumps from 0-150 psi in a fraction of a second.

The famous range of Fireward plastic bodied powder extinguishers made from the 60's to mid 80's was phased out of production for metal bodies as there was no way of determining the safety of the shell until discharge (& cartridge extinguishers were slowly loosing popularity).

Obvious UV damage is fading & grey of the plastic, mottling and crazing, but I've seen failures in apparently fine plastic components. Impact damage can weaken a part with no external signs either.

We have a rare example of a firm actually servicing properly for once - don't knock them!

[Tadees]

I was not enquiring about the dangers to service engineers. What I wanted to know is whether degradation has any risk (low or high) if the building user was to use it to put out a fire.

[lingmoor]

not knocking him Anthony...just puzzled by the BS

[Tom Sutton]

Tadees I would say it would have the same risk to an operator as to an engineer but the level of risk would be difficult to determine.

IMO the level of risk is not helped by the BS which confuses the issue as commented by Lingmoor. I think Action 1 in the extended service,  "If a plastic headcap is coated in such a way as to disguise deterioration (eg painting) replace with a new headcap" should not be in extend service as the headcap is change anyway, but added to the general basic service action 3 and I can see a case for including a visual inspection for degradation in the RP inspection. I would think the more it is checked, would reduce the risk.

[AnthonyB]

I was not enquiring about the dangers to service engineers. What I wanted to know is whether degradation has any risk (low or high) if the building user was to use it to put out a fire.

Of course it does! If the plastic is degraded & then subject to an instant exponential increase in pressure (by activating the extinguisher) then you at the same risk of failure and injury whether building user or engineer.

In fact a building user is at greater risk as a trained engineer knows not to stand over an extinguisher they are disassembling or discharging.

The current BS is terribly written & wouldn't win any Clear English awards. In practice, obviously plastic damaged heads should be replaced on the annual service, all plastic heads 5 yearly.

[Psuedonym]

It's not just BS that don't win any awards Anthony, the Ansul R102 manual also has oddities within the instructions which contradict each other making a maintenance decision very difficult when you're on nights and knackered.
The brain cells (either of them) are either go to sleep or just panic and hide!

[lingmoor]

Just found this...

The British Fire Consortium, the UK's largest fire trade association, has warned of the serious danger
presented to technicians when servicing extinguishers with degraded plastic heads.
Three years ago, Steve Clark, a service engineer with BFC member company, Anglia Fire, lost a finger and
suffered severe facial injuries when an extinguisher he was decommissioning exploded in his face.
The British Fire Consortium gives an example of a fire extinguisher with a degraded plastic head
Steve explains, "I was lucky it didn't kill me.
I was holding the extinguisher with my left hand, leaning over it ready to remove the head, when it simply
exploded".
"The head shattered into pieces, shooting the cartridge up to the ceiling like a rocket, and breaking my jaw as it
went past".
Incidents such as this led to one of the many recent revisions to BS 5306-3:2009 which relates to the
commissioning and maintenance of portable fire extinguishers.
Graham Newman, president, BFC warns that in spite of the revision, technicians still need to exercise caution.
Plastic heads are subject to degradation and can react as described above when the extinguisher is pressurised.
This situation is even more likely if the service technician tries to dismantle the extinguisher.
The standard was revised to ensure that all plastic heads are replaced with a new plastic head at the extended
service every five years.
Graham said: "There are still a lot of extinguishers with plastic heads older than five years out in the field but,
at least service technicians can be a little more confident as these heads gradually get removed".
"Should a technician come across one, our advice would be, rather than stand over it to remove the head, it
should be laid on its side, with the head facing away from you, before removing it carefully, with gentle use of a rubber mallet if required - ensuring that at all times, you are not in the line of fire from both the head or the
body".
Graham added: "Technicians should be aware that some unscrupulous companies have been known to make the
valve look like new during a basic service using black shoe polish or WD40, but of course this just masks the
fault for next year's engineer".
"

[MonkeyBoy]

In line with the initial question on this topic......

A firm has just serviced the extinguishers, for the Charity I oversee, and condemned our 9ltr water extinguisher for having a plastic valve assembly.

They did, of course, sell us a nice new extinguisher to replace it!!

The staff on duty were told that it was because of the possibility of the valve exploding (or similar) if the extinguisher was operated.
I was going to contact the firm but, thanks to this topic and forum, won't need to now as the reasoning was genuine!


I will, however, be contacting them to ask why they decided to change the discharge horn on our CO2 extinguisher (that they supplied, new, about 2 years ago) without explanation!

Keep up the good work FireNet!