Chapter 28: Class B Fires

Question 1

Class B Fire:TDG/NFPA & WHIMS defined Flammable Liquid as

Answer 1

TDG: A Flammable Liquid as one that has a flash point 60.5’C

NFPA/WHIMS: Define it as one with a flash point below 37.8’C

Question 2

Class B Fire & Explosion Prevention

5

Answer 2

• Exclusion of Ignition source
• Exclusion of air(O2)
• Storage of liquids in closed containers/systems
• Ventilation to prevent accumulation of vapor with in the flammable range
• Use of inert gas atmospheres

Question 3

Extinguishment of class B

Answer 3

Shutting off fuel supply
Exclusion of air(vapor suppression)
Cooling to stop evaporation
Combination of these

Question 4

Pressurized flammable gases have following characteristics

Answer 4

Pressure
Diffusivity
low boiling points
colorless/odorless
Creates static electricity when flowing

Question 5

Safety release devices

Answer 5

Pressure relief valve
Rupture discs
Fusible Plugs

Question 6

Gas color coding

Answer 6

Silver/Green: O2
Blue: Nitrous oxide
Orange: Cyclopropane 
Brown: Helium
Red: Ethylene
Grey Carbon Dioxide

Question 7

3 types of Container stresses

Answer 7

Thermal, Chemical, Mechanical

Question 8

5 methods of Container Breach: stressed beyond their limits of recovery

Answer 8

Disintegration
Runaway Cracking
Attachments open
Puncture
Split

Question 9

13 gases lighter than air

4H MEDIC ANNA

Answer 9

Hydrogen
Helium
Hydrogen Cyanide
Hydrogen Fluoride

Methane
Diborane
Illuminating gas
Carbon MonOxide

Acetylene
Neon
Nitrogen
Anhydrous Ammonia

Question 10

container release types

Answer 10

Hemispheric
Plume
Cloud
Cone 
Stream
Pool

Question 11

LPG(liquid petroleum Gas)

Answer 11

boiling point -90'C to -1.1'C
Stored in pressurized vessels
-Cylinders(454kgmax)
-Tanks
-Lines

Pressure Range 170-17000kpa

Term LPG =Propane, Propylene, n-Butane, Isobutane, and Butylene

Question 12

BLEVE

Answer 12

Boiling
Liquid
Expanding 
Vapor 
Explosion

Question 13

Bleve warning

Answer 13

Pressure relief device working
pitch or sound gets loader
Pings,pops,snaps
Steam=above 100'C
discoloration of shell & impingement
bulged or bubble

Question 14

if we have flame impinging on tank

Answer 14

Cool tank from top down
Large tanks fail in 10-20 min
use master stream appliance
non survivable area of 500'
water must not turn into steam it must reach container

Question 15

Natural Gas

Answer 15

Explosive range 5-15%

Question 16

Propane

Answer 16

1.5 x as heavy as air so it sinks

low ignition temp. 450”C

Question 17

Foam Ops

Answer 17

• Foam creates a barrier between fuel and fire
• Lowers temp of fuel and adjacent surfaces
• Prevents release of flammable vapors
• Penetrates product to get at hot embers

Question 18

3 steps of generating and applying foam

Answer 18

Proportioning
Foam Generation
Distribution

Question 19

Proportining

Answer 19

Mixing foam concentrate with water
Most concentrates are to be mixed 94%-99.9% water
(6%max concentrate)

4parts foam con. + 96 parts water= 100 foam parts solution

Question 20

We use Niagra A-B foam but there are 4 other types

Answer 20

AFFF: Aqueos film forming Foam: thin layer that covers liquid
Alcohol resistant: barrier against solvents
Fluoroprotein: below ground fuel tank
High-expansion foam: voids

Question 21

Niagra A-B foam

Answer 21

Detergent free
Can be properly discharged through all fog nozzles
 Long shelf life
can be used with other foams
can be used on both A & B fires

Question 22

Class A foam %’s

Answer 22

0. 1%: deep seated fire
1. 1-0.5%: wildland/grass fire
2. 5%: Structural FF w/fog Nozzle, wild land surface w/foam nozzle
3. 0%: exposure protection Barriers for wild land

Question 23

Class B Foam %

Answer 23

1. 0% shallow hydrocarbon spills
2. 0% on sever hydrocarbon spills and polar solvents
3. 0% for Hazmat Vapor suppression

Question 24

4 methods foam is proportioned

Answer 24

Induction:in-line eductor (old pump)
Injection: External pump forces foam into the fire stream
Batch mixing: pour foam directly into pumps water tank
Pre mixing:used in fire extinguishers

Question 25

2 Application Systems

Answer 25

Manual: educator & pipe lay 1400-2100kpa: max 60m of hose from where ever it is set up in line: 65mm hose and add 50 kpa FL max 4 lenths of 44 or 65 (60meters
Automatic: built into new pump

Question 26

3 application techniques

Answer 26

Roll on
Bank down
Rain down

Question 27

Foam works beat

Answer 27

1.7 to 27’C
water is free of detergents
follow manufactures spec.s
minimize loss of suction do to air leaks

Question 28

fire in tanks

Answer 28

slop over
boil over
froth over