SUPPRESS WILDFIRE

Question 1

What are the critical dimensions of a safe area, in relation to flame height?

Answer 1

The size of this ‘safe’ area is proportional to the size of the flames and the fire intensity. The rule is that you need to be able to retreat to somewhere that is, in distance from the flames, four times the flame height

Question 2

Heavy smoke at a bushfire can be a serious threat to your wellbeing. What are the three (3) acceptable ways to minimise this hazard?

Answer 2

• Always carrying your smoke mask and goggles and using them where necessary
• Avoiding unnecessary exposure to heavy smoke
• If trapped in heavy smoke, seeking fresh air pockets close to the ground

Question 3

As a possible witness to an accident and subsequent investigation, when possible, you should take notes to assist. Describe the types of information you should be recording.

Answer 3

• The nature of the event
• The location
• Details of events leading up to the accident
• Personnel involved, including any eye-witnesses
• Initial action taken
• Any subsequent action

Question 4

In implementing a defensive strategy of asset protection, what must be done immediately after the fire front has passed?

Answer 4

After the fire front has passed, check all structures for fire. Continue to check structures − ignition and early fire is often not obvious. Look particularly underneath buildings, under eaves, in roof cavities and in any openings that may have been entered by embers.

Question 5

Machines such as bulldozers, working in a direct attack role on forest fires, should have what support?

Answer 5

If machines are making a direct attack on the head or flank of the fire, they should be closely supported by tankers.

Question 6

What does the term mineral earth mean, in relation to constructing control lines?

Answer 6

When used in the context of fire control refers to a non-flammable surface (either natural or prepared) which provides a break in understorey, litter and humus fuels and hence a barrier (of varied effectiveness depending, among other things, on its width and the intensity of the approaching fire) to fire travelling on or near the ground surface.

Question 7

Under what circumstances are defensive strategies necessary?

Answer 7

• Extreme fire behaviour is occurring (for example, flame height greater than 4 − 5m)
• Limited firefighting resources are available
• The fire is remote and not able to be immediately attacked

Question 8

Why should back burn lighting crews be kept as small as possible?

Answer 8

This avoids confusion and minimises the danger to lighters working in from the control line, particularly in forest fuels.

Question 9

What is a major safety consideration in making a parallel attack on a bushfire?

Answer 9

Crews should always ‘take the black with them’ in parallel attack so that control line construction crews can retreat to burnt ground quickly in the event of a change in flank fire behaviour.

Question 10

Who can authorise back burning?

Answer 10

All backburns must be authorised by the incident controller

Question 11

List three (3) sudden changes in fire behaviour that may affect crew safety while conducting firefighting operations at bushfire incident.

Answer 11

1. Increases its rate of spread
2. Increases its intensity (flame height)
3. Changes its direction of spread

Question 12

How can you minimise the risk of injury from falling limbs and trees?

Answer 12

• Always wearing an approved hard-hat
• Being conscious of overhead hazards − inspect trees above your locality for evidence of broken limbs that may fall
• Being aware of trees in your vicinity with weakened butts or trunks because of the fire − such trees should be identified and felled

Question 13

List three (3) causes of heat illness?

Answer 13

• Radiant heat from the fire
• Environmental heat (the heat of the air around us)
• Dehydration (excessive fluid loss through sweating without adequate fluid replacement)

Question 14

List and briefly describe the three (3) main factors that affect the fire behaviour of a bushfire.

Answer 14

1. Fuel – what type of vegetation is burning, different fuels will cause different intesity
2. Topography - the lay of the land (for example, hills and gullies) and will have considerable
   impact on the way a fire will travel
3. Weather - Weather has a strong effect on fire behaviour. Key weather factors which can influence the behaviour of fire include temperature, humidity, precipitation, wind, atmospheric stability and lightning

Question 15

Before a backburn is lit, the OIC must be satisfied that five (5) conditions are met. What are these conditions?

Answer 15

1. A satisfactory control line has been established from which to light the backburn
2. Weather and fuel conditions mean the backburn will be controllable
3. Adequate resources are present to light the backburn and prevent its escape
4. Adequate communications are established to maintain an appropriate flow of information during the activity
5. Sufficient time exists for the backburn to penetrate far enough so that the junction zone effect will not endanger the control line

Question 16

What are the major advantages of making an indirect attack on a bushfire?

Answer 16

An indirect attack involves falling back some distance from the fire perimeter and backburning from a strong control line
* It is the only offensive strategy that is effective against large, intense fires
* Enables choice in locating control lines
* Allows use of defensible, existing barriers
* Allows greater time for control line construction
* Crews are not affected by heat and smoke (until backburning commences)

Question 17

List three (3) hazards unique to the mop-up and patrol phases of a bushfire incident.

Answer 17

1. Fire may have weakened tree trunks and branches so these may fall. Look up for overhead hazards, and look out for fire-weakened trees
2. The fire may have burnt out fuel that supported rocks or logs on a slope, allowing these to roll downhill. Always look for upslope hazards in hilly terrain
3. Snakes and spiders may be agitated and could pose a greater than normal risk to firefighters. Take care when moving or splitting open logs or stumps

Question 18

In an initial attack at a bushfire, who establishes a Control Point and where?

Answer 18

On arrival at the fire, the IC must establish a Control Point. The CP must be set up in a location that is capable of accepting and staging the requested recourses, not in the path of the fire, nor creating a hazard to traffic or the public and must be able to maintain comms with COMCEN and RDC.

Question 19

LACES is a safety check before fighting or lighting a fire, which must be continually re-evaluated as conditions change. Provide a brief explanation of each component of the LACES bushfire safety acronym.

Answer 19

L LOOKOUTS
* Competent firefighter/s?
* Safe vantage point?
* Map and good communications?
* Everybody ‘looks out’ for the safety of everybody on the fire ground

A AWARENESS
* Terrain, weather, fire behaviour?
* Do you understand your assignment?
* Do you know what other crews are doing?
* Is everybody aware of the fire’s current and anticipated behaviour and of other fire ground hazards?

C COMMUNICATION
* Map and radio, reliable contact?
* Everybody speaks up and everybody listens, about what is happening and their concerns at the fire.

E ESCAPE ROUTES
* Suitable? Checked?
* Known to everyone?
* Everybody has an agreed ‘out’ plan, just in case things turn bad.

S SAFETY ZONES
* Suitable?
* Big enough? Close enough? Free of hazards?
* Everybody helps everybody else to survive; everybody supports the

Question 20

List four (4) precautions that you (or residents) can take before the fire front arrives, to help avoid ignition of structures?

Answer 20

• Ensure all doors and windows are closed and secured
• Block down pipes and fill gutters with water if possible
• Remove doormats, move outdoor furniture off timber decks and away from the building
• Wet down structures and surroundings (preferably with foam)

Question 21

Backburning is a strategy used throughout Western Australia in fire suppression. It can be dangerous if carried out under the wrong conditions. List two (2) disadvantages of using a back burn?

Answer 21

• The backburn may escape and create a new fire front ahead of the main Fire
• If the wind changes, a backburn may become an active front and threaten the proposed control line at another location where a backburn may not yet be established
• Erratic fire behaviour may occur at the junction zone between the spreading edge of the bushfire and the backburn, leading to spotting across the control line if the junction zone is not a sufficient distance in from the control line

Question 22

How far should you keep from a bulldozer working in the forest?

Answer 22

When bulldozers are pushing over trees, keep two tree lengths clear (due to the ‘domino’ effect of one tree knocking down another)

Question 23

Describe the Dead Man Zone and its potential consequences.

Answer 23

The Dead Man Zone is an area near the fire edge which could be consumed by a moving fire within five minutes

Question 24

Why is direct attack on grass fires most often effective from the burnt side of the fire edge?

Answer 24

• Is easier to manoeuvre on the burnt ground (obstacles are more obvious)
• Is safer in the event of a sudden change in fire behaviour − because fuel has been consumed
• Allows better application of water to the base of burning material

Question 25

As a rule, what is the maximum flame height that may allow a direct attack?

Answer 25

Flame heights are about 1.5 m or less

Question 26

Give a brief description of the three (3) basic types of fires? (Ground, Surface, Crown)

Answer 26

Ground fires generally burn below the ground in fuels such as peat, coal, sawdust, humus (fuel on ground), underground dead roots or sub-surface logs. Ground fires burn slowly and can be a problem as they can burn unnoticed.

Surface fires are the most common type of fire that firefighters encounter. Surface fires include grass, scrub, heathland and forest fires. Surface fires can have extreme rates of spread depending on the type of fuel and its loading. These fires may involve extreme spotting distances.

A crown fire burns on the tops of trees above and in front of a strong surface fire. Radiant heat and direct flame rising from the surface fire ignites the treetops.

Question 27

Summarise acceptable fuel and weather conditions for backburning?

Answer 27

• Wind, relative humidity and fuel moisture content. If winds are too strong, humidity too low, and fuels too dry, control of the backburn will probably be lost. It is essential to take actual weather readings on site, and know trends in the weather pattern (local forecasts). As a general rule, the McArthur fire danger index should not exceed 12
• Possible changes in wind direction must not be able to threaten the backburn. If possible delay lighting the backburn until evening or overnight when the fire danger is moderating
• Fuel adjacent to the control line. In forested areas, stringybark trees close to the control line provide a big risk of spotting. If possible rake around them prior to lighting the backburn, or wet them with foam. Dangerous fuels on the non-fire side of the control line can be wetted with foam or other retardants prior to lighting the backburn

Question 28

When would a spot ignition pattern be used to light a backburn along the edge of a control line rather than using a line ignition pattern?

Answer 28

Where it is essential that fire intensity be minimised, spot fire ignition is preferable to ignition with lines of fire.

Question 29

What is the blackout distance as per SOP 3.5.1 – Bushfire Response for the following fuel distribution types -

Answer 29

• Ground Fuels (grass, mulch, logs etc.) 25m
• Vertical Fuels (trees, structures, fencing etc.) 100m