34.50-5—Classification—TB/ALL.
(a)
Portable and semiportable extinguishers shall be classified by a combination letter and number symbol. The letter indicating the type of fire which the unit could be expected to extinguish, and the number indicating the relative size of the unit.
(1)
“A” for fires in ordinary combustible materials such as mattresses, piles of wood, shavings, canvas, etc., where the quenching and cooling effects of quantities of water, or solutions containing large percentages of water, are of first importance.
(2)
“B” for fires in combustible or flammable liquids such as gasoline, lubricating oil, diesel oil, greases, etc., where a blanketing or smothering effect is essential.
(3)
“C” for fires in electrical equipment where the use of non-conducting extinguishing agent is of first importance so that electrical shock is not experienced by the firefighter.
(c)
The number designations for size will start with “I” for the smallest to “V” for the largest. Extinguishers which have a gross weight of 55 pounds or less when fully charged are considered portable. Extinguishers which have a gross weight of more than 55 pounds when fully charged are considered semiportable and shall be fitted with suitable hose and nozzle or other practicable means so that all portions of the space concerned may be reached. Examples of size graduations for some of the typical portable and semiportable extinguishers are set forth in Table 34.50-5(c).
| Classification type (Size) | Soda-acid and water (Gallons) | Foam (Gallons) | Carbon dioxide (Pounds) | Dry chemical (Pounds) |
|---|---|---|---|---|
| A-II | 21/2 | 21/2 | ||
| B-I | 11/4 | 4 | 2 | |
| B-II | 21/2 | 15 | 10 | |
| B-III | 12 | 35 | 20 | |
| B-IV | 20 | 50 | 30 | |
| B-V | 40 | 1 100 | 1 50 | |
| C-I | 4 | 2 | ||
| CC-II | 15 | 10 | ||
| 1 For outside use, double the amount shall be carried. | ||||