Fire Extinguishers and should you believe the label

[eyecatcher]

As part of our annual Health Authority inspection we needed to provide an extra fire extinguisher. One on the upper floors was seemingly adequate for the last 6 years.

Another one the same is all that’s necessary but on the ground floor.

So I was looking for a multi use dry chemical, size 10lbs.

 

After spending some time looking at the ratings and performance in a few different stores I was still bamboozled and you will see why at the end.

 

First the boring bit so stick with it?

 

Fire extinguishers have letters to identify the class of fire so you will see:

A  (“ash”) for wood, paper, textiles,plastics

B (“Barrel”) for oil, kerosene, petrol, diesel

C (“Current”) for electrical equipment

D (“Dynamite”)  for bombs and explosives

K (“Kitchen”) chip pan fires, cooking oil, grease

 

On every extinguisher you will see a rating for example 2A-2B; 6A-14B

2A in simple terms means it is capable of dealing with a fire on a wooden panel 10ftx10ft; 4A is for 14ftx14ft and 6A for 17ftx17ft.

Each A is equivalent to 1.25 gallons of water; 4A should be 5 gallons

 

2B means it is capable of dealing with 6 gallons of petrol and 10B 31 gallons of petrol.

Each B is 1ft2  of liquid fire.

 

Ok so you are now armed like me with all the basic info to go and buy an extinguisher.?

 

Wife had done the pricing research and said Home Pro have the best deals at the moment and after checking Global, TW,Toolmart, she was right.

 

They had about 4 different brands, which upon close inspection were all identical containers, all identical handles only the silver stickers identified the brand.

 

My first head scratch was to question how three containers each 10lb gross weight could claim to be able to extinguish a bigger fire than the previous one, despite the fact that they all said the discharge time was between 13-15 seconds; and the pressures are all set at 13.45kpa.

 

I have a 2A-2B priced at 685bt; the 4A-10B was 699bt, the 6A-20B was 1220bt

 

It seems the extinguishing agent in these medium sized containers is monoammonium phosphate (sodium bicarb in the small kitchen sized ones)

 

I bought the 4A-10B in the end, but I left with little confidence in the labelling and pricing.

 

By the way the famous imported brands(which I forget!!) were circa 1700bt and upwards

 

So; same container with different abilities, possible or dubious?

[Crossy]

Interesting, I've never really looked at the ratings, just the content weight and price, going for mid-range units.

 

Now I look I see in our home:-

• Two x Imperial brand 4.5kg, rated as  6A-20B (one in my workshop, one on the upstairs landing).
• One Mercury brand 6.8kg, rated as 4A-10B (downstairs common area).

So, a bigger weight, apparently less performance.

 

So I too wonder what to believe, and how many people even know what the ratings mean?

 

We have a fire blanket in the kitchen (although a damp towel seems to be the weapon of choice), we may want to eat what Madam has attempted to cremate.

 

EDIT Even more confusing is when I look at a couple of UK sites I see similarly sized units rated at 21A-133B (at twice the price mind).

 

EDIT 2 Maybe UK ratings are different, I see units for sale in the US with ratings of 4A-80B (@ USD 110).

 

[Kwasaki]

12 hours ago, eyecatcher said:

D (“Dynamite”)  for bombs and explosives

Interesting this made me laugh,  scenario  " It's a bomb, hey you grab the 'D' Fire extinguisher I'm off ".

[eyecatcher]

I too checked the uk websites and noted much higher numbers which lead me to believe that you are paying for the extinguishing agent inside the can. Does it vary?

Personally looking at the containers they are all identical, maybe some global player like Chubb is selling cans around the world and they are being filled with water?....so basically fake knock offs

[Maybole]

I have been looking also at fire extinguishers with the same amount of puzzlement. Madam would prefer a proper fire blanket, but I have as yet been unable to find one. Has anybody seen them on sale in the Chiangmai area?

[eyecatcher]

Maybole, yes fire blankets are the modern version of the wet tea towel for the old chip pan fire..

so they are a kitchen aid.

 

Home pro have them in now (you may even see my three bottles still lined up)

You can also get them at the safety centre which is almost next door to the Robinsons entrance on H.D.road.

 

Global dont have but like everything else they often dont have and have no intention of stocking up.

[eyecatcher]

Its not often I would cast aspertions on my own post but........

would you 'king believe it.

 

Global had two(2) fire blankets.440bt mind'.....but maybe reusable I dont know

 

[Maybole]

Thank

4 hours ago, eyecatcher said:

Maybole, yes fire blankets are the modern version of the wet tea towel for the old chip pan fire..

so they are a kitchen aid.

 

Home pro have them in now (you may even see my three bottles still lined up)

You can also get them at the safety centre which is almost next door to the Robinsons entrance on H.D.road.

 

Global dont have but like everything else they often dont have and have no intention of stocking up.

Thank you, I will be there tomorrow.

[Dazinoz]

The best extinguishers for their size used to be the BCF. They were banned in Australia due to their ozone depleting chemicals. They were a powder like dry chemical extinguishers but so much more effective. I had a couple a long time after they were banned because they don't deplete the ozone layer if not used and if I needed to use them I would not have cared at that time.

[DGS1244]

Some where you have got confused with the classifications, D for dynamite never happened. What about electrical circuits?? The subject is too large to make any sense here but a few words of advice from a long standing fire engineer. Powder works well but gives major cleanup problems for small fires, particularly on electrical circuits. Also cannot be used in any moving vehicle and anywhere where there is a constant vibration, the vibration causes compaction of the power and then they fail to discharge. CO2 on electrical OK but try on a fat fire and you can blow the ignited oil everywhere spreading the fire. Plain water extinguishers can be fine on some fires and foam on oil and fat fires. As far as size goes buy the largest you  and any ladies or children in the premises can handle, too large and they become too awkward to handle and you need practice to be effective and that can be difficult to obtain.

 

The are many publications on the subject and Thailand has some reasonable regulations regarding types and numbers etc.

[Crossy]

52 minutes ago, DGS1244 said:

The subject is too large to make any sense here but a few words of advice from a long standing fire engineer.

Any idea why seemingly similarly sized units have radically different fire ratings?

 

[DGS1244]

3 minutes ago, Crossy said:

Any idea why seemingly similarly sized units have radically different fire ratings?

 

Yes Different sources of ignition require different extinguishing agents. Some products extinguish certain types of fire much easier than others, water on paper, foam on oil, etc. That is why you have to be careful in your selection especially if there are electrical supplies present. Unfortunately the days of using Halon for everything for us mortals has gone, still can be used in satellites etc. though. Although dry chemical powder works well on most things there are some limitations and the clean can be horrendous for a very small fire. There are also many on the market in Thailand that still have an ozone depletion potential and should not be used, they all quote fancy names and numbers which actually means very little, just a sales ploy

[Crossy]

7 minutes ago, DGS1244 said:

Yes Different sources of ignition require different extinguishing agents.

Understood, but our OP has three extinguishers of the same physical size and indicated weight which have very different A and B ratings (and prices). Different active ingredient or something else?

 

Quote

I have a 2A-2B priced at 685bt; the 4A-10B was 699bt, the 6A-20B was 1220bt

 

Also, are the quoted weights nett or gross? 

If gross then less active element and more sand(?) in the tank could be thre reason, which immediately causes me some worry.

[DGS1244]

2 minutes ago, Crossy said:

Understood, but our OP has three extinguishers of the same physical size and indicated weight which have very different A and B ratings. Different active ingredient or something else?

 

Yep you got it, different ingredients, which can get very confusing . There are a few good simple guides on the market but if I publish them here I might be in contravention of some regulation unfortunately.

[Crossy]

11 minutes ago, DGS1244 said:

I publish them here I might be in contravention of some regulation unfortunately

Understood, anything that's on the net is fair game for at least a link.

[DGS1244]

5 minutes ago, Crossy said:

Understood, anything that's on the net is fair game for at least a link.

For Info try

 

Fire Protection Association

https://www.thefpa.co.uk/

1.  

[eyecatcher]

Well, for sure on every container I have inspected there is no list of ingredients.

The intrrnet will tell you about the ammo..phosphate in medium sizes and sodium carb in the kitchen handy sizes but yet the discharge time is the same circa 13-15seconds for a 10lbs.

And whoopee, for your extra 800bt to jump to a 15lbs bottle you get maybe an extra 3seconds.

 

I am long past the days of paying 800bt for 3 seconds but i suppose its still worth it for some.

[TigerGuardian]

A Class D extinguisher is for use on combustible metals such as magnesium.