Hi all,

Recently i've been seeing a lot of literature about water mist extinguishers and, other than the comparatively high cost, they seem to be the perfect option for construction sites in that they fight pretty much all classes of fires: class A, B, C, F and electrical.

This flexibility would make providing fire cover to our sites much simpler (only one type of extinguisher to worry about rather than 3 or 4), would make managing our "fleet" of extinguishers much simpler and would also eliminate the risk of people picking up the wrong extinguisher in an emergency situation and potentially making things worse.

My question is, why are these things not everywhere? Is it purely a cost thing (which i appreciate may be an issue in some situations) or is there another issue which i'm not aware of?

Any opinions would be greatly appreciated

Stern

I can buy 3 x 6 litre AFFF extinguishers for less money than 1 x 6 litre water mist.

I will get a total rating of 63A and 432B from the combined output of all three extinguishers, compared with the 13A & 21B of the water mist. So why would I bother changing??




A 6 litre water mist gives a rating of 13A, 21B, 75F for around £107
A 6 litre AFF gives a rating of 21A 144B for about £30
A 3 litre Wet Chemical has a rating of 8A 55B 75F for £80

Source: safelincs.co.uk

Stern, maybe some people simply don't believe water and electrical fires can mix ?

No, I am not missing the point at all

In one on 'my' buildings, we have about 750 extinguishers - for predominantly A & Electrical fires. We also have a number specialist class D extinguishers but only 2 units for class F

So how can I justify spending £1000s on water mist when (like most buildings) we don't have class C & F fire risks in every area?

Our fire points consist of 2 x 6l AFFF and a 2kg CO2 giving a combined rating of 36A & 366B plus electrical coverage at each point, We simply do not need expensive water mists as they bring nothing extra to the party

Hi Mssy,

Thanks again for your response but you've missed the point of my initial post (which may have been my fault for not explaining it properly)

My question was regarding the use of water mist extinguishers on construction sites, not in permanent buildings. In a permanent building its easy to be able to put a specific extinguisher in a specific room and even assess the ability of the specific occupant of the room to use it.
Construction sites are different beast entirely.

- The VAST majority of the people working on site won't be employed directly by the company managing the site and providing and providing the extinguishers. Furthermore, many will not speak English as a first language.

-With the best will in the world, many won't have received formal training in the use of extinguishers and may not know what extinguisher does what. Yes i know they SHOULD have training, but in reality they won't have and we have to base our risk assessments on reality, not an ideal version of it.

-The environment is constantly changing. Whilst a water extinguisher might be appropriate in an area in the morning, by the afternoon something else is going on in that area and the water is now no use or worse, actually becomes a hazard. Of course the response form those behind a desk is to "review your risk assessment" but in reality this is extremely difficult to keep on top of on a busy site. I'd even go as far as saying it's bordering impossible.

Taking the above into consideration, the water mists seem the perfect fit for construction sites and whilst they are becoming more popular, i was just wondering why they haven't seen the overnight success that things like wifi linked fire alarms did. One day we were turning bells, the next day every site in the country seemed to have these magic little red boxes! :-)

You seem to be on top of things at your building and i applaud you for that as with 750 extinguishers i'm sure that was one hell of a job! However, with the age old message being that extinguishers should only be used for small fires, i would question why you actually NEED 366B of fire fighting power at every fire point? Is it not a case of using a sledgehammer to crack a walnut?