flammability limits problem (fire)

[moquiton]

hellos i am working this the gases produced by a fire. i need to know how to know when this mixture of unburn and burn gas + air is flammable?

thank a lot

Christian.Perez@ulg.ac.be

 

[25362]

Since apparently the mix components, the temperatures, and proportions in the mix, are all unknowns, the advisable procedure is to take samples and do lab-bench checking of their flammability.

If you are after proper ventilating methods to prevent fires and explosions, at ambient temperatures, there are empirically determined design criteria for ventilation systems for flammables inside storage and process areas. Published guidelines are:

For storage areas.

Rate: complete room air change at least six times
per hour.
Conditions:
=>Control switch and lights must be outside the storage
area.
=>Vent control and lights must be operated by same switch.
=>A pilot light must be installed next to switch if Class I
flammables are dispensed in area.

For processing areas inside buildings.

Rate: 1ft³/min/ft<sup>2[/sub] of solid
floor area.
Conditions:
=>Make-up air must not short circuit ventilation system.
=>Ventilation must limit flammable concentration not more
than five feet from equipment exposing Class I liquids
to air.

Please note that although ventilation may bring flammables below the LFL, their concentration may still exceed their TLV.</sup>