Fire scene safety

Question 1

Fire scenes are an unstable environment

Answer 1

Fire scenes are without doubt one of the most unstable environments in which to work. The fire scene may be safe initially, however, due to the effects of the fire, may become unsafe during the post fire incident investigation, risk assessments must remain updated and reviewed to ensure staff safety.

Investigators often find themselves:
- searching through an unstable structure
- excavating the scene to identify the cause of a fire.

Question 2

Injuries through hazards

Answer 2

At a fire scene most injuries are received from these hazards:
- Inhalation of toxic substances e.g. car fires emit particularly toxic and harmful gases
- Injestion of particles et.
- Cuts/wounds from sharp objects
- Air borne dusts, particles etc.
- Tripping on fire debris
- Falling down, over, onto or into any obstructions or cavities
- Items from above falling onto you or hitting objects and causing a chain reaction.

To identify the best method of proptection, you must consider:
- an assessment of each of the above
- a strategy to prevent an occurrence or to mitigate its impact.

Question 3

Clothing protection

Answer 3

Protective clothing must be used by the on-scene investigator. These items are required:
- a suitable helmet (that complies with the relevant safety standard)
- a pair of overalls
- nose and mouth filter, a full face respirator or full BA (if required and qualified)
- gloves
- safety glasses
- heavy duty footwear with steel soles and toe caps.

Question 4

Fire scene risks

Answer 4

Timber
This will normally burn and char but in most instances will, if members are thick enough, maintain sufficient integrity. When entering a timber structure, take note of the thickness of structural members, the load it is carrying, and any sound emanating from structural members.

Steel
In the initial stage of a fire, unprotected steel will expand and can cause external and internal walls to be pushed out. However, if there is sufficient fuel available, the unprotected steel will lose strength and collapse, pulling walls inwardly.
When the heated steel is cooled by fire fighting hose lines or the passage of time, it tends to contract and may:
- fall off supports or similar or
- remain intact loosely but may collapse during excavation or movement of items with little or no warning.

Concrete
Concrete, and in particular tilt slab construction, is the most unpredictable as it can be affected by extremely low fire temperatures, and topple like a deck of cards, in all directions. When subjected to fire, concrete can break away at the surface (spalling), and steel reinforcing may be exposed to sufficient heat to lose its tensile strength.
Look for concrete spalling, exposed steel in the concrete, discoloured areas of concrete such as blue or green, and cracking. With tilt slab reinforcing construction, are the fixing cleats exposed or grouted?

Masonry
Masonry and brick structures, when subjected to fire, can be weakened by deterioration of the mortar, expansion of the wall or damage to supporting or connected structural members. Visible signs of damage or weakness include cracking, leaning or bowing or collapse of supporting floors or roof frames.