Monday 22 March 2010

Forest and Woodland Firefighting

The UK is classed as a low fire risk area, as we have a fairly regular rainfall pattern and no designated dry season unlike many other countries, particularly those in the tropics. However in the event of a prolonged hot dry spell we do have the potential for wildfires and these can have drastic results.

Heather particularly has the potential to be combustible as it dries out rapidly in all seasons and is what is known as a “fine fuel”.

There are three types of fires that can occur in forest and heathland, these are:
  • Surface fires where the fuel burns at or near ground level, these are the most common fires in the UK.
  • Ground fires where in dry conditions the organic soil layers themselves catch fire, these are difficult to detect and extinguish.
  • Crown fires where the surface fires ascend into the tree canopy, which can move very quickly and become very intense, this is often caused where “ladder fuels“ which are vegetation linking the ground to the crown of the trees lets the fire spread upwards. These are not very common in the UK.
There are various ways of tackling the fires including the use of water and or chemical foams to put out the fire and also dampen the surrounding areas preventing the fire spreading. Also fire breaks can be made by using shovels or mechanical diggers to remove the vegetation and make a bare earth barrier across which the fire cannot spread. The oxygen supply can be interrupted by the use of beaters.

Beaters can be broken down into three basic classes; Short handled approximately 1.9m to 2.2 m with a belt head, the head is manufactured from conveyor belt material; Long handled approximately 2.8m with a wire mesh head and Long handled with a flat metal plate sometimes these have additional chains attached. The long handle obviously keeps the person further back from the heat, but can sometimes be difficult to handle and unwieldy to transport.

Fatigue

Firefighting is a strenuous activity which normally takes place in difficult conditions, and can lead to heat stress, heat exhaustion and possibly heat stroke.

Everyone involved should be aware of heat-induced illnesses and know how to treat the symptoms and call for help when necessary.

The symptoms of heat stress are weakness, dizziness and nausea. Where a firefighter is removed from the fire front and given water, rest and shade, recovery will usually take place quite quickly.

Medical treatment may be required for these heat-induced illnesses and the patient should be given water and kept cool. Often firefighters may fail to sufficiently replace body fluids even when they have drunk sufficient to quench their thirst.

The fluid replacement taken in may be only half of what is actually required. Plenty of water should be drunk as soon as sweating occurs, before fire suppression starts and often more than is felt necessary. The recommended amount is 1 litre of cool (not chilled) plain (sugar free) water per hour.

To reduce fatigue carbohydrate foods such as bread, pasta and cakes are recommended.

Managers should ensure that teams have sufficient suitable food and water on site during prolonged fire suppression.

Awareness

When working in these conditions it is absolutely essential for all involved to remain aware of what is happening around them. Be particularly aware of moving around on terrain whilst visibility is reduced because of poor light smoke and water sprays.

Watch out for changes in conditions for example shifts of wind direction and speed, look out for the fire moving onto steep slopes or circling behind you, look out also for changes in the type of vegetation.

Always maintain line of sight and communication with your colleagues.

Remember the following safety aid “WATCH OUT” that can be found on the AFAG leaflet 803
Weather dominates fire behaviour
Actions must be based on current and expected fire behaviour
Try out at least two safe escape routes
Communications must be maintained with your crew leader and adjoining crews
Hazards to watch for are steep slopes and the amount of fuels
Observe changes in wind speed and direction, humidity and cloud
Understand your instructions
Think clearly be alert and act decisively before your situation becomes critical

Personal Protective Equipment

As with any activity where there are safety issues the correct PPE must be worn:
  • A brightly coloured Flame Retardant cotton boiler suit i.e. Proban complying with EN 531, is recommended do not use non FR synthetic clothing particularly nylon.
  • Also recommended is the use of a protective neck cloth.
  • Protective boots with good grip and ankle support complying with EN ISO 20345. It is suggested that these should also be heat resistant.
  • Suitable protective gloves, non-synthetic e.g. leather.
  • Safety helmet complying with EN 397.
  • Eye protection complying with EN 166, to prevent eye damage from particles and embers. Helmet mounted face shields can also protect from radiant heat.
  • Hearing protection complying with EN 352 where the noise level exceeds 85 dB.
  • Respiratory masks where there is a danger of dust or particles.
As well as these essential items each person should carry water for personal consumption and to wash any burns, also a personal first aid kit, not specifically for burns. A specialised burn first aid kit must be available on site.

Granite Workwear offer a number of items that are suitable for use in these conditions including Proban Cotton Overalls in Orange, Sip Protection Firefighters Chainsaw Protective Trousers, Peltor Hearing Protection, Fortec Boots that are Heat Resistant to 300° C, Hard hats, Venitex Respiratory Masks, Bolle Eye Protection, fire retardant neck tubes & balaclavas and Venitex gloves.

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