Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Chemistry of Hazardous MaterialsFifth Edition • Eugene Meyer
Chapter 3
Flammable Gases and Flammable Liquids
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Liquid Flammability
• Lower explosive limit– Minimum vapor concentration
• Upper explosive limit– Maximum vapor concentration
• Flammable range– Numerical difference between upper, lower
limits
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Liquid Flammability (cont’d)
• Combustible gas monitor– Determines concentration of substance in
air
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Temperature and Flammable Liquids
• Flashpoint– Minimum temp at which there is sufficient
vapor to form ignitable mixture
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Temperature and Flammable Liquids (cont’d)
• Fire point– Temp at which self-sustained combustion
occurs• Auto ignition point
– Temp at which self-sustained combustion occurs without ignition source
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
OSHA/NFPA Definitions
• Flammable liquid (Class I liquid)– Flashpoint < 100° F
• Combustible liquid (Class II liquid)– Flashpoint > 100° F
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
“Emptied” Tanks
• When liquid is removed, some vapor always remains within container or storage tank– Precautions always
should be exercised
Courtesy of GfG Instrumentation, Inc., Ann Arbor, Michigan.
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Accelerants
• Flammable or combustible solids, liquids, gases
• Used to initiate, promote fire spread• Confirmation by lab analysis
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Resource Conservation and Recovery Act
• Wastes classified by ignitability characteristics
• Subject to EPA regulations as it pertains to treatment, storage, disposal
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
RCRA Characteristic of Ignitability
• Waste exhibits ignitability if it is– flammable gas, as defined in DOT
regulations – liquid with flashpoint equal to or less than
140º F (60º C)– material other than liquid capable “of
causing fire by friction, absorption of moisture, or spontaneous chemical”
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
RCRA Characteristic of Ignitability (cont’d)
• Waste exhibits ignitability if it is– flammable solid, as defined in DOT
regulations – oxidizer, as defined in DOT regulations
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Storing and Transporting Compressed Gases
• Compressed gas– Gas confined under
pressure• Liquefied
compressed gas– Under moderate
pressure, gas liquefies
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Compressed Gas Storage
• Avoid damaging cylinder• Secure in upright position• Protect valve using protective cap• When moving cylinders, they should be
secured to appropriate cart
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Compressed Gas Transport
• DOT approves containers for use only upon heating (70° F to 130° F) and where pressure does not exceed five-fourths of container’s service pressure
• Cylinders must be secured for transport
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Compressed Gas Transport
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
General Hazards ofCompressed Gases
• Cylinders that rupture due to rapid increase in pressure may behave as airborne missiles
• Flammable gases can mix with air, ignite
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Transport Vessels
• Compressed gases, liquefied compressed gases routinely transported within cargo tanks, railroad tank cars
• Special concern given to situations where containers are engulfed in fire
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Transport Vessels
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Incidents Involving Release of Compressed Gases
• Vessels exposed to intense heat are likely to rupture
• Contact CHEMTREC• Determine degree of hazard• Use water to cool exposed containers• With small leaks, use water fog to
disperse gas or vapor
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Incidents Involving Release of Compressed Gases (cont’d)
• Don’t try to move cylinder if concentration of escaping gas or vapor is in flammable range
• Use total encapsulating suit, self-contained breathing apparatus when moving slowly leaking cylinder
• Position cylinder so point of leakage becomes uppermost part of cylinder
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Incidents Involving Release of Compressed Gases (cont’d)
• Emergency responders should never approach head or end of tank or cylinder
• Grounding required to transfer substances between vessels
• Firefighters in area of leaking gas should wear total encapsulating suits– Use self-contained breathing apparatus
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Incidents Involving Release of Compressed Gases (cont’d)
• Combating major fire involving flammable compressed gas should not be undertaken unless escape of flammable gas from cylinder or tank can be stopped
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Evacuation
• With cylinders containing flammable or nonflammable gas, personnel should be evacuated to at least 1000 ft in all directions (2000 ft for public)
• Tanks require 2500 ft for firefighters (5000 ft for public)
• Use unmanned monitor to cool tank
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Storing Flammable Liquids
• When not in use, containers and tanks should be sealed to prevent spills or vapor leakage
• Class I flammable liquids should be dispensed only from containers or tanks that have been electrically grounded
• OSHA regulates storage of flammable liquids in workplace
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Storing Flammable Liquids (cont’d)
• Allowable maximum volume varies with – Flashpoint of liquid– Manner by which it is stored– Whether storage is indoors or outdoors
Courtesy of Justrite Manufacturing Company, Des Plaines, Illinois.
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Storing Flammable Liquids (cont’d)
Courtesy of A & A Sheet Metal Products, Inc., SE-Cur-All® Products, LaPorte, Indiana
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Portable Tanks
• Closed container not intended for fixed installation possesses liquid capacity of 60 gallons
• Portable tanks require one or more devices for emergency venting under fire conditions
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Storage Within Stationary Tanks
• Types– Atmospheric tank– Low-pressure tank– Pressure vessel
• Tank farm: collection of tanks– Containment is
provided
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Transporting Flammable Liquids
• DOT authorizes bulk shipments when shipper, carrier have loaded them into transport vessels constructed according to specified requirements that comply with – Certain allowable maximum filling limits– Testing– Maintenance– Marking, placarding– Other requirements
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Transport by Motor Carrier
• Types– Cargo vans
• Liquids contained in steel drums– Cargo tank/semi-trailer combination
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Transport by Railroad Tank Car
• Types– Nonpressure tanks
• Outlets, external heater lines located on bottom• Valves, pressure-relief devices located on top
– Pressure tanks• Internal pressure tested to 100-600 psi
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Thermal Protection
• Thermally “insulated” tank cars: constructed so external heat is transferred to contents very slowly under normal conditions
• Thermally “protected” tank cars: constructed so external heat cannot be transferred to contents under abnormal conditions
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Responding to FlammableLiquid Incidents
• Most serious incident involves release of flammable liquid– And/or ongoing fire impinges vessel
• Boiling liquid expanding vapor explosion (BLEVE)– When external heat is applied to vessel,
contents produce more vapor, increasing internal pressure, causing vessel to rupture
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
Responding to FlammableLiquid Incidents
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
General Procedures
• Determine type, amount of flammable liquid– Chemical nature
• Identify other hazardous materials in immediate vicinity
• Contact CHEMTREC, National Response Center
• Select appropriate extinguishing agent
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
General Procedures (cont’d)
• Use water fog to disperse vapors for small spill or leak
• Cool nearby containers• When vapor has not yet ignited, monitor
concentration of flammable vapor in air– Use fog to disperse vapors, reduce
concentration
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
General Procedures (cont’d)
• Steps to stop leak should be done only when concentration of vapors is outside flammable range
• Foam may be used to confine flammable vapor
• Dikes can be used to prevent spread of liquid
Meyer, Chemistry of Hazardous Materials, Fifth Ed.© 2010 by Pearson Education, Inc., Upper Saddle River, NJ
General Procedures (cont’d)
• Move upright railroad cars from overturned tank cars whenever practical
• Firefighters should wear total-encapsulating suits, self-contained breathing apparatus