Flammable and Combustible Liquids
by Environmental, Health and Safety Services
Overview
• Definitions
• Classes of Liquids
• Precautions
• Storage Requirements
• Preventive Measures
Isopropyl alcohol
Toluene
Diethyl ether
Methyl formate
Acetone
Ethyl etherKerosene
Lacquer
thinner
Gasoline
MEK
Flammable Liquids
• Flammable liquids can cause a fire or explosion, and like many other substances, they can also cause serious health effects from overexposure.
Note: On the NFPA diamond label, a fire hazard rating of 3 or 4 denotes a
flammable liquid.
3
Flammable Liquids
• A flammable liquid is any liquid having a flashpoint below 100°F.– Exception: Any mixture having
components with flashpoints of 100°F or higher, the total of which make up 99% or more of the total volume of the mixture.
Note: The flash point is the lowest temperature at which a liquid gives off enough vapor to form a flammable
mixture with air.
Flammable Liquids
• The vapors of flammable liquids often present the most serious hazard.– The vapors can easily
ignite or explode.– Flammable liquid vapors
are heavier than air and may settle in low spots, or move a significant distance from the liquid itself.
Explosive Limits
• The explosive concentration of vapors in air has a lower and upper limit.– The Lower Explosive Limit (LEL) is the
lowest concentration that will ignite.– The Upper Explosive Limit (UEL) is the
highest concentration that will ignite.– If the vapor concentration is between the
LEL and UEL, there is serious risk of fire or explosion.
Explosive Limits
Above the Upper Explosive Limit, the mixture is too rich to burn
UPPER EXPLOSIVE LIMIT
Explosive Range
Below the Lower Explosive Limit, the mixture is too lean to burn
LOWER EXPLOSIVE LIMIT
Classification
• Flammable and combustible liquids are classified according to their flashpoints.
This is important to know because the quantity of
flammable/combustible liquids that can be stored in any one location is determined by the
class of the liquid.
Flammable Liquids
Class 1A Liquids having flashpoints below 73°F and having a boiling point below 100°F.
Class 1B Liquids having flashpoints below 73°F and having a boiling point at or above 100°F.
Class 1C Liquids have flashpoints at or above 73°F and below 100°F.
Combustible Liquids
• A combustible liquid is any liquid having a flashpoint at or above 100°F.
Note: Check your Material Safety Data Sheet (MSDS) sheet for the characteristics or classification
of a particular liquid.
Combustible Liquids
Class II Liquids with flashpoints at or above 100°F and below 140°F.
Class III Liquids with flashpoints at or above 140°F
Class IIIA Those with flashpoints at or above 140°F and below 200°F.
Class IIIB Those with flashpoints at or above 200°F.
Area Exempt Amounts
• There are certain amounts of flammable and combustible liquids stored in each control area that are considered exempt.– If these amounts are exceeded, then the area
or building may have to be reclassified as a Hazardous Use Group under the building code.
Excessive storage is a serious violation of the
fire code!
Contact the EHSS Fire Safety Engineer at 231-9198 for assistance, if necessary.
Storage Areas• Flammables should be stored in an approved
cabinet in a cool, well ventilated area to avoid pressure buildup and vaporization.
Storage Areas
• There should be at least one fire extinguisher in the area.– Large storage areas should
have a fire protection system installed and must be approved for this use.
Storage Cabinets• Use flammable liquid storage cabinets
where greater quantities of liquids are needed.
Contrary to popular belief, these cabinets are not designed to contain a fire, but to prevent an outside fire from reaching the contents for a period of 10 minutes – enough time to evacuate the area.
Flammable Liquid Exempt Amounts (in gallons)Condition IA IB IC
Inside; unprotected by sprinklers or cabinets.
30 60 90
Within approved cabinet; unsprinklered structure.
60 120 180
Not in approved cabinet; sprinklered structure.
60 120 180
In approved cabinet; sprinklered structure.
120 240 360
Outside storage. 60 120 180
Combustible Liquid Exempt Amounts (in gallons)
Condition II IIIA IIIB
Inside; unprotected by sprinklers or cabinets.
120 330 13,200
Within approved cabinet; unsprinklered structure.
240 660 26,400
Not in approved cabinet; sprinklered structure.
240 660 unlimited
In approved cabinet; sprinklered structure.
480 1,320 unlimited
Outside storage. 240 660 unlimited
Limitations on Storage
The maximum storage of flammables and combustibles
in any one area under the Virginia Fire Prevention Code is 60 gallons of flammables and 120 gallons of combustibles.
These quantities must be in an approved storage area, i.e. a flammables cabinet or other acceptable means.
There are also limitations on quantities stored in individual
containers.
Storage Containers
• Containers should be tightly sealed when not in use.
• Approved safety cans are recommended for smaller quantities.– The spring-loaded safety cap
prevents spillage, prevents vapors from escaping, acts as a pressure vent if engulfed in fire, prevents explosions and rocketing of the can!
Flammable Liquid Limitations(in gallons)
Container IA IB IC
Glass or approved plastic 1 pt. 1 qt. 1
Metal (other than DOT drum) 1 5 5
Safety cans 2 5 5
Metal drums (DOT specifications) 60 60 60
Approved portable tanks 660 660 660
Combustible Liquid Limitations(in gallons)
Container II III
Glass or approved plastic 1 1
Metal (other than DOT drums) 5 5
Safety Cans 5 5
Metal drums (DOT specifications) 60 60
Approved portable tanks 660 660
Precautions
• The unsafe use, storage, dispensing, or disposal of flammable materials can be a prime source of fires and explosions.– Read labels of all spray cans
to identify those with flammable gas-propellants.
Ex. Butane and Propane
Precautions• Some flammable liquids have a
tendency to accumulate a static electric charge, which can release a spark that ignites the liquid.– Always bond metal dispensing and
receiving containers together before pouring.
Precautions• To bond containers, each
container is wired together and one container is connected to a good ground point to allow any charge to drain away safely.– Because there is no easy way to
bond plastic containers, their use should be limited to smaller sizes (no more than 4L).
Precautions
• Overexposure to flammable liquids may present health hazards.
• Consult the Material Safety Data Sheet (MSDS) on the material you will be using to identify health hazards and protective measures to be taken.
Precautions
• Effects of overexposure to flammable liquids includes:– Inhalation: Irritation to respiratory
passages, nausea, headaches, muscle weakness, drowsiness, loss of coordination, disorientation, confusion, unconsciousness, and death.
Precautions
– Skin Contact: irritated, dry, cracked skin, rashes, dermatitis.
– Eye Contact: burning, irritation, eye damage.
– Ingestion: irritated digestive tract, poisoning, death.
Preventive Measures
• Quantities of flammable and combustible liquids located outside of storage cabinets should be restricted to one day’s supply, or to what can be used during a single shift.– If possible, substitute nonflammable, non-
hazardous materials for flammable liquids.
Preventive Measures
• To prevent the accumulation of vapors inside of storage areas, a continuous mechanical ventilation system must be in place.
Preventive Measures• All nonessential ignition sources must
be eliminated where flammable liquids are used or stored.– Common ignition sources include:
• Open flames from cutting and welding• Furnaces, matches, heaters, smoking materials• Static electricity, friction sparks• Motors, switches, circuit breakers
Preventive Measures
• Materials that contribute to a flammable liquid fire should not be stored with flammable liquids. For example,– Oxidizers– Organic peroxides
Preventive Measures• If a spill occurs:
– Limit spread by diking with suitable absorbent material.
– Minimize vapors by covering surface of spill with same absorbent material.
– Ensure all sources of ignition are off or controlled.
– Notify your supervisor immediately and call 911 if necessary.
Preventive Measures• If a spill occurs:
– Begin cleanup right away.• Sweep saturated absorbent material into a
dustpan.• Place material into a metal container with a tight
fitting lid.• Place any saturated rags or cloths into the same
container.• Contact EHSS at 231-2982 for pickup and proper
disposal.
Preventive Measures
• Always check the labels of containers (or the MSDS) for recommended personal protective equipment to be worn.– Lab coats– Splash aprons– Eyewear– Gloves– Overboots
Summary
• Careless mistakes and safety shortcuts lead to serious problems when it comes to flammable liquids.
• Respect flammable liquids and their dangers - their hazards are deadly…
Contact Information
• Environmental, Health and Safety Services– www.ehss.vt.edu– 231-5985
• Fire Safety– [email protected]– 231-9198