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– Firesafe@vt.edu– 231-9198