BS5306, part 8 - table 2

[Hi Tower]

It is detailed in table 2 of the above standard that the amount of wet chemical required to extinguish a cooking oil fire increases accordingly with respect to the surface area of the cooking oil vat; e.g. 0.06 square metres = 5F extinguisher, 0.27 square metres = 75F + 25F.  This makes sense until you reach the last example which states  0.40 square metres = 75F.  Why in this case where the surface area increases does the amount of wet chemical media required decrease?  Is it as simple as a misprint or am I missing something?

[deaconj999]

Good Question,

The more I looked, the more confusing it got. It must be a typo and not just one, if I try to reason the calculation regardless of derating it got worse.

Where's my Rubiks Cube.......

[AnthonyB]

no, it refers to 2 x 75F.

Column one is area where two extinguishers are used.

Row 1 is therefore 2 x 5F
Row 2 2 x 15F
Row 3 2 x 25F
Row 4 a 75F + a 15F
Row 5 a 75F + a 25F
Row 6 2 x 75F

[deaconj999]

I get it now, thanks, although it would have been better put in a table like this maybe

Maximum surface area to be extinguished (m2)   Minimum Extinguisher(s) required
0.015                                                                       1 x 5F
0.02                                                                       1 x 15F
0.04                                                                       1 x 25F
0.06                                                                       2 x 5F
0.08                                                                       2 x 15F
0.11                                                                       1 x 75F
0.13                                                                       2 x 25F
0.24                                                                       1 x 75F + 1 x 15F
0.27                                                                       1 x 75F + 1 x 25 F
0.40                                                                       2 x 75F

[Hi Tower]

Thanks AB
Like D999 says the table could be presented better, like shown - but thank you for the explanation