Flammable and Combustible liquids as per NFPA

 

According to NFPA 30 – Flammable and Combustible Liquids Code, liquids are classified based on their flash point (the lowest temperature at which a liquid gives off enough vapor to ignite) and boiling point.

NFPA 30 Classification of Flammable and Combustible Liquids

Class	Flash Point	Boiling Point	Examples
Class IA	Below 22.8°C (73°F)	Below 37.8°C  (100°F)	Diethyl ether,    Pentane
Class IB	Below 22.8°C (73°F)	At or above 37.8°C (100°F)	Acetone, Petrol,    Benzene
Class IC	At or above 22.8°C (73°F)     and below 37.8°C (100°F)	—	Turpentine, Styrene
Class II	At or above 37.8°C (100°F)    and below 60°C (140°F)	—	Diesel Fuel,     Kerosene
Class IIIA	At or above 60°C (140°F) and below 93°C (200°F)	—	Fuel Oil, Mineral Oil
Class IIIB	At or above 93°C (200°F)	—	Lubricating Oil,  Vegetable Oil

Categories

Flammable Liquids

Liquids with a flash point below 37.8°C (100°F):

• Class IA
• Class IB
• Class IC

Examples:

• Gasoline (Petrol)
• Acetone
• Ethanol
• Methanol
• Toluene

Combustible Liquids

Liquids with a flash point at or above 37.8°C (100°F):

• Class II
• Class IIIA
• Class IIIB

Examples:

• Diesel
• Kerosene
• Furnace Oil
• Lubricating Oil
• Hydraulic Oil

Key Definitions

Flash Point

• The lowest temperature at which a liquid produces sufficient vapor to ignite in the presence of an ignition source.

Boiling Point

• The temperature at which a liquid changes into vapor.

Storage Requirements (NFPA 30)

• Store flammable liquids in approved safety containers or tanks.
• Keep away from heat, sparks, open flames, and hot surfaces.
• Provide adequate ventilation to prevent vapor accumulation.
• Bond and ground containers during transfer of flammable liquids.
• Store incompatible chemicals separately.
• Install appropriate fire extinguishers (e.g. Dry Chemical Powder, Foam, or CO₂ depending on the hazard).
• Display "Flammable – No Smoking" warning signs.
• Maintain spill containment and emergency response equipment.

Fire Extinguishing Media

Liquid Type	Recommended Extinguishing Agent
Petrol (Gasoline)	Foam, Dry Chemical Powder (ABC/BC), CO₂
Diesel	Foam, Dry Chemical Powder
Kerosene	Foam, Dry Chemical Powder
Alcohol	Alcohol-Resistant Foam, Dry Chemical, CO₂
Solvents	Foam, Dry Chemical Powder, CO₂

Examples in Industrial Facilities

Material	NFPA Classification
Petrol (Gasoline)	Class IB (Flammable)
Acetone	Class IB (Flammable)
Ethanol	Class IB (Flammable)
Methanol	Class IB (Flammable)
Diesel	Class II (Combustible)
Kerosene	Class II (Combustible)
Furnace Oil	Class IIIA (Combustible)
Hydraulic Oil	Class IIIA or IIIB (depending on flash point)
Lubricating Oil	Class IIIB (Combustible)