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incident response unit

Incident Response Units

We have three Incident Response Units (IRU's). They are stationed at Chelston Business Park in Somerset and Okehampton and Bovey Tracey Fire Stations in Devon.


They are supplied by the Government to respond to incidents involving mass decontamination. Mass decontamination is defined as incidents where more than one person can be decontaminated simultaneously using the same equipment.

Each IRU is maintained by a host station with help from other stations which receive training on the equipment.

Vehicle Specification

  • A MAN appliance
  • Vehicle length - 11.2 m
  • Height - 3.3m
  • Width - 2.54m
  • Weight - 21 tonnes

The vehicle is fitted with a differential lock for use in crossing soft or muddy ground. It also has:

  • Rear wheel drive
  • a radio
  • a mobile phone
  • a printer.

Mass decontamination equipment

All equipment is stored in cages on the vehicle, six on each side..

Forklift Truck

A forklift truck is carried on the rear of the IRU and is used to remove the equipment cages. Trained fork lift truck operators are required to carry out this procedure.

Disrobe and re-robe packs

Casualties place all their clothing and belongings into a bag and are given a disrobe pack to wear until they are ready to be decontaminated, by walking through a shower system. Once casualties have showered they will be given a re-robe pack to dress in. This consists of a towel, filter mask, paper underwear, paper suit, jacket and trousers, socks and shoes, and personal hygiene items.

Gas Tight Suits

A one-piece integral suit including gloves and permanently bonded boots with steel toecap covers the firefighter and breathing apparatus set.

They are worn for protection against hazardous substances: chemicals, biological hazards and asbestos.

The suit is made of a high performance multilayer polymer fabric with a semi ridge polyester laminated visor and has a limited life of five years.

Each IRU has 48 suits.

Powered Respirator Protection Suits

A one-piece coverall suit, of similar construction to the gas tight suit. They have an air filtration unit to bring air from atmosphere into the suit. This removes the need for compressed air breathing apparatus and therefore extends the wearing duration of the suit.

The suit is only designed for wearers within the 'warm zone'. Their duties will include handing out dis-robe packs, helping casualties in the warm zone and marshalling casualties through the shower.

Each wearer is also supplied with a Gas Monitor, Radio and internal Camel-Back for re-hydration.

Tent structures

There are three different tent structures, which are used for different roles:

  • dis-robing
  • decontaminating
  • re-robing.

Trained fire crews erect the tents and guide casualties through the decontamination process. Once decontaminated casualties are handed over to the Ambulance crews for assessing and further treatment if required.

Hot water showers

There are two lines of five showers separated by curtains which allows up to ten people to be decontaminated at a time. The water for the shower is delivered at a temperature of 35 degrees centigrade. The shower consists of a two minute wash followed by a one minute rinse.

The system is able to decontaminate up to 200 ambulant casualties or 100 non-ambulant casualties (on stretchers) per hour.

For injured casualties the stretcher is placed on a conveyor system to go through the decontamination process.

Hot air blower

Provides fume free hot air to the tent structure for a comfortable temperature to be maintained.

Diesel generator

Used to heat the water boiler and hot air blower and submersible pump.

Submersible pump

For use only in the mass decontamination structure. The pump is placed in the shower section to discharge 6000 litres of contaminated water per hour into the dam. Powered by a 110-volt generator.

Firefighter Decontamination Shower

A shower with a heavy-duty air inflated frame and integral sump.

Six shower positions, which can be fitted with spray heads or washing brushes. The shower system is provided with an induction facility that allows automatic induction of up to two decontamination solutions.

A small 110V pump is provided to transfer the decontamination waste to a storage receptacle at a rate of 130 litres a minute.


Two 6000 litre capacity dams to contain contaminated water. The dams have inflatable collars to rise with the water level. Removable covers to contain the water are kept afloat by bladders attached to their undersides.

Telescopic lighting unit

Provides an adjustable lighting source up to a height of 6 metres.

Mobile Data Transmission

Provides a satellite navigation system, with GPS mapping and Chemdata chemical retrieval information.

The Chemdata system allows crews to access a database on how to deal with a known chemical, including:

  • Substance identification number or UN number
  • How the substance reacts
  • What form it may appear in
  • Emergency Action Code
  • Additional Personal Protection required
  • Tremcard numbers
  • Extinguishment/decontamination measures
  • Environmental risks/hazards
  • Precautions
  • First Aid
  • Telephone numbers and addresses for specialist advice

The GPS mapping system

Allows the crews to zoom in on a specific location identified by name or six figure grid reference. It can also show the vehicle location and direction it is travelling in relation to the incident location.

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