Guideline for a Mandatory Code of Practice > Prevention of Fires at Mines > Annexures

(For information purposes)

"FIRE TRIANGLE"

(Oxygen, Heat, Fuel plus Chain Reaction) fires start when a flammable material or liquid, in combination with a sufficient quality of an oxidizer such as oxygen gas or oxygen-risk air is exposed to a source of heat or ambient temperature above the flash point for the fuel /oxidizer mix, and is able to sustain a rate of rapid oxidation that produces a chain reaction.

"Four (4) stages of a fire"

By most standards including IFSTA, there are 4 stages of a fire. These stages are incipient, growth, fully developed, and decay. The following is a brief overview of each stage.

"Incipient"

This first stage begins when heat, oxygen and a fuel source combine and have a chemical reaction resulting in fire. This is also known as "ignition" and is usually represented by a very small fire which often goes out on its own, before the following stages are reached. Recognising a fire at this stage provides the best chance at suppression or escape.

"Growth"

The growth stage is where the structures, fire load and oxygen are used as fuel for the fire. There are numerous factors affecting the growth stage including where the fire started, what combustibles are near it, ceiling height and the potential for "thermal layering". It is during this shortest of the 4 stages when a deadly "flashover" can occur; potentially trapping, injuring or killing fire-fighters.

"Fully Developed"

When the growth stage has reached its maximum and all combustible materials have been ignited, a fire is considered fully developed. This is the hottest phase of a fire and the most dangerous for anyone trapped within.

"Decay"

Usually the longest stage of a fire, the decay stage is characterised a significant decrease in oxygen or fuel, putting an end to the fire. Two common dangers during this stage are firstly - the existence of non-flaming combustibles, which can potentially start a new fire if not fully extinguished. Secondly, there is the danger of a back draft when oxygen is reintroduced to a volatile, confined space.

Flammable liquids are classified in terms of the latest version of SANS 10089-1:

1.1.1

Class 0: liquefied petroleum gases (LPG);

1.1.2

Class 1A/B: liquids with a closed-cup flash point below 23°C:

1.1.3

Class 1C: liquids with a closed-cup flash point between 23 and 38°C;

1.1.4

Class 2: liquids with a closed-cup flash point between 38 and 60, 5°C;

1.1.5

Class 3A: liquids with a closed-cup flash point between 60, 5 and 93°C; and

1.1.6

Class 3B: liquids with a closed-cup flash point of 93°C or above.

Physical and chemical properties of fuel sources properties include flammability, can impact the level of a fire risk. These ignitability, combustibility (fire spread capacity or fire retardant effect), self-extinguishing properties, toxicity of paralysis products and other unique characteristics. Safety Data Sheets (SDSs) from suppliers in compliance with SANS 10234 (2008): Global harmonized system of classification and labelling of chemicals and system or process design specifications from designers should be consulted to identify and categorise fuel sources.

Mine Health and Safety Act, 1996 (Act No. 29 of 1996)

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