Chapter 11 – Exposures

Protecting exposures will vary on many factors. Fire Officers should be able to identify exposures; and understand how tactical operations can affect, create and eliminate exposure problems.

Types of Exposures

Internal: fire extends from one area to another within a structure

External: fire extends from the fire building to surrounding buildings/property

Internal Exposures

Fire can travel through natural pathways like concealed spaces, stairs, chutes and shafts. It can also extend vertically up the exterior from building windows or other openings

The concept of protecting interior exposures is to keep fire away from areas that can become involved with fire. These areas can be divided by firewalls. The greater the fire rating, the more protection the exposure has from being involved. Protecting valuables such as computer equipment, company/personal records, stock and machinery can have very favourable outcomes.

External Exposures

Protection of external exposures is critical

Should be prioritized in terms of

Life safety

Extinguishment

Property Conservations

Adjacent Buildings

Improper Ventilation can expose buildings

Consider fire apparatus and equipment parked near the fire building

Separate buildings, whether attached to the fire building or not, are classified as exterior exposures

General exposure distances:

A building up to 30 feet from the fire is classified as an exposure

A building 30-100 feet from the fire may be classified as an exposure

A building more than 100 feet from the fire is not an exposure

These are not definite rules due to:

What is burning

Radiant heat being produced

Weather conditions

Wind and direction of travel

Protecting Exposures

Dependant on available staffing and apparatus resources

Using water on the exposure is the most effective way of protection

Directing a stream between buildings is less effective

Radiant heat travels through transparent materials such as water

Tactics for Protecting Exposures

Coordinated attack on the fire with an adequate flow is the best way to protect exposures

Wash the face of exposed buildings with water to prevent ignition of exposed surface areas by reducing the amount of heat absorbed

Push the fire back into the original area to prevent extension to exposures

Reduce the intensity or extinguish the fire at the points where heat transfer is threatening exposures

Place ventilation holes where the change in convection currents will draw fire away from exposures

Stretch lines to the inside of exposures to cover the possible outbreak of fire

Charge sprinkler system of exposure, if available so that the system is not overwhelmed if fire extends into the exposure

Radiant Heat Considerations

Involves the distance of the exposure and the heat output of the fire

The closer a building is to the fire building = the greater the radiant heat being absorbed

Exposures above/higher than the fire are also at a greater risk

Wind direction

Life hazard in the exposure

Hazard presented by the exposed occupancy

Prioritizing Exposure

Distance between exposed structures

Volume and location of fire