Extinguishing Powders

General Principle of Dry Chemical Powders

Operation 

Dry chemical powders extinguish fires in two primary ways:

• Chemically,they disrupt the combustion reaction by blocking free radicals and lowering the temperature.

• Physically,they form a cloud that smothers the flames, cutting off oxygen and creating a solid barrier around the fire.

 

They are particularly effective on flammable liquid and gas fires (Classes B and C).
The most common BC powders are based on sodium bicarbonate (NaHCO₃) or potassium bicarbonate (KHCO₃), the latter providing superior performance, especially in critical environments.

 

Advantages 

Whether used in portable extinguishers or fixed suppression systems, dry chemical powders offer several key benefits: 

• Fast extinguishing: Immediate flame knockdown, even in high-intensity fires (fuel, flare stacks, LNG).

• Electrical safety: Non-conductive, suitable for use on live electrical equipment.

• No thermal shock: Preserves materials sensitive to heat.

• Versatile: Usable in both portable extinguishers and fixed systems.

• Ideal for High-Risk Environments: Including oil facilities, ships, helipads, and offshore platforms.

• Easy to use: Good flowability and moisture resistance in onboard systems.

 

Types of Dry Chemical Powders

There are two main types of BC dry chemical powders, each with specific characteristics:

Sodium bicarbonate-based powders (NaHCO₃): Economical and widely used, effective on flammable liquid and gas fires (Classes B and C).

Potassium bicarbonate-based powders (KHCO₃): Higher performance, especially for intense fires (such as LNG), but more expensive. Recommended for high-risk sites (offshore platforms, refineries, etc.).