TABLE OF CONTENTS A room 5 m wide, 4 m deep, and 2.5 m high has one vent that is 2 m high and 3 m wide. The fuel load is 10 lb/ft 2. The enclosure is made of gypsum plaster on metal with the following properties:
k = 0.47 W/m C
? = 1440 kg/m3
c = 0.84 kJ/kg C
Find the maximum temperature of the fire and its burning duration.
Law's method is recommended for all roughly cubic compartments and in long, narrow compartments where 
is approximately less than or equal to 18 m -1/2. Since this room is roughly cubic, Law's method is applicable.
Thus,
Where:
| mf = | m ? f A floor |
| m ?f = | 10 lb/ft 2 or 49 kg/m 2 |
| A floor = | 20 m 2 |
| mf = | 49 20 = 980 kg |
and
where W is width of the room and D is depth of the room.
This equation is valid for
and in this case
To ensure that predictions are sufficiently conservative using Law's method, the predicted burning rate should be reduced by a factor of 1.4.
The adjusted burning rate is then
The burning duration can be found by
A room 7 m wide, 28 m deep, and 4 m high has one vent that is 4 m high and 3.5 m wide in one of the small end walls. The fuel...
