FireNet Community
FIRE SERVICE AND GENERAL FIRE SAFETY TOPICS => Fire Safety => Topic started by: deaconj999 on November 11, 2010, 07:13:51 PM
-
Can anyone please shed some light on the fact that according to this table for a fire with surface area of 0.4 m2 you would need 2 x 75F Fire extinguishers.
Have I go this right that a 20 cm x 20 cm surface area which just over A4 paper size you would need to have to hand 2 x 6 ltr wet chem extinguishers to put a fire out.
I am missing the point here I know, but I can't discover why, it seems I need 12 lts of extinguishing medium for a cooking oil fire with a surface are about A4 size.
-
Have I go this right that a 20 cm x 20 cm surface area which just over A4 paper size
GFSM I think your calculations may have gone a bit awry 0.4m2 is a bit more than 400cm2 more like 4000cm2.
-
Have I go this right that a 20 cm x 20 cm surface area which just over A4 paper size
GFSM I think your calculations may have gone a bit awry 0.4m2 is a bit more than 400cm2 more like 4000cm2.
.4 of a square metre is nearly half of it. So the surface area is around 1M x 1/2M ish which is around half the size of a desk which is around A1 ish size.
Fire ground calcs you understand.
-
This is where the metres squared and square metres becomes a too complicated for simple minds like mine but as far as I can see from the original post its asking for a fire with a surface area of 0.4m2 - I see that as 40cm x 40 cm?
I obviously don't know about the depth of the tray and contents or if it has been pre-heated but two 6ltr extinguishers doesn't seem excessive - I'd imagine one 6 litres isn't enough and it could be a question that 7 litres would be sufficient rather than the 12 quoted?
-
I see that as 40cm x 40 cm?
Closer to 63.25 cm X 63.25. I think.
-
Have I go this right that a 20 cm x 20 cm surface area which just over A4 paper size
GFSM I think your calculations may have gone a bit awry 0.4m2 is a bit more than 400cm2 more like 4000cm2.
.4 of a square metre is nearly half of it. So the surface area is around 1M x 1/2M ish which is around half the size of a desk which is around A1 ish size.
Fire ground calcs you understand.
NT, you are truly a genius, as I was having a wierd moment, my brain was stuck in reverse gear for a while, i haven't had to use the simple part of my brain for a long time to calculate something so simple. Thankyou for the kick start with your simple description, I'll have to go and see a doctor next time the cogs get stuck
-
Have I go this right that a 20 cm x 20 cm surface area which just over A4 paper size
GFSM I think your calculations may have gone a bit awry 0.4m2 is a bit more than 400cm2 more like 4000cm2.
.4 of a square metre is nearly half of it. So the surface area is around 1M x 1/2M ish which is around half the size of a desk which is around A1 ish size.
Fire ground calcs you understand.
NT, you are truly a genius,
I know.
-
Thanks Tom; I'd read this as 0.4m x 0.4m whereas its (as you rightly point out) 0.4 x 1.0m which is 4000cm2, the square root of 4000 being 63.25. Of course the guidance is written for any shape of container whereas I'd wrongly assumed a square/rectangle so it makes perfect sense now I actually think about it.
-
Good Job I asked then
-
For any single risk that calculates as needing more than a single 75F extinguisher other than for travel distance/access issues I would consider that a fixed system is required.
Although if you look at the size of a 75F test tray you would be hard pressed to find a commercial fryer with a single compartment bigger.
Quite a few smaller establishments could suit the various 2 & 3 litre models available, which being cheaper are more likely to be installed, but whilst a lot of companies only push the mega 6 litre version (or don't do F class at all thinking ABC Powder, CO2 or non aspirated AFFF actually work)
This clip shows why powder extinguishers don't really do the business, using a real situation:
http://www.youtube.com/watch?v=X4GPxV_2vV0
-
They say " A picture is worth a thousand words " how true.