Choosing the correct fire extinguisher

Choosing the correct fire extinguisher requires some thought, both  in terms of likely fire hazard and the changing rules regarding fire extinguishers. My notes following will clarify the key considerations.

Phase out of Halon in Portable Fire Extinguishers

Introduction

Halon fire extinguisher manufacturers originally emphasised that Halon 1211 was an all-purpose, efficient medium suitable for any class of fire due to:

  • Its rapid knockdown
  • Its efficiency in terms of the volume and weight of medium required
  • Its safe use in occupied areas and on electrical equipment
  • It being clean in use, with no residues to clean up after the fire was extinguished

Most of these were reasonable claims. However, Halon 1211 was not as good as some other extinguishers in dealing with Class A fires and its use outdoors could be less than effective. But in the right environment and correctly used Halon 1211 was a very useful addition to the armoury of the professional and non-professional firefighter particularly in dealing with aircraft fires, in the computer fires and telecommunications fires. It is also used widely with the military and a whole host of other applications in transport, hospitals and the emergency services.

The Halon 1211 extinguishers quickly gained in popularity under the weight of promotional activity carried out by the manufacturer and the portable extinguisher producers. Since the 1960s, the use of Halon 1211 in portable extinguishers has been promoted as the answer for most fire fighting situations. Why is this now not the case?

Present Situation

When the Montreal Protocol (relating to CFCs) was signed in 1987, many UK manufacturers took the decision to withdraw halon 1211 extinguishers from their product ranges immediately and to concentrate on other products. This action has substantially limited the number of such extinguishers in use and thereby minimised the problem of complying with the Montreal Protocol.

The European Council regulation 2037/2000 has the same implications for halon portable fire extinguishers as for fixed systems: This means that halon portable fire extinguishers extinguishers must not be used in the EC and the only exceptions are for use in some applications in civil aircraft, by the armed forces and by the emergency services for the protection of people.

The Alternatives

There is no single direct replacement for halon 1211 for use in portable extinguishers. In order for an agent to be effective in portable extinguishers, it has to have certain properties, streaming for one, which enables it to be applied to the fire in the right concentrations and without vapourising too quickly.

The halocarbon’s (CFCs) and (HCFCs), were phase-out under the Montreal Protocol. and a number of fire extinguishing halocarbon gases with zero ozone depletion potential (ODP) have been developed. The substitute gases used for firefighting purposes tend to be fluorinated gases belonging to a class of chemicals known as hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs).

These fluorinated gases are not fully acceptable in Europe. HFCs (hydrofluorocarbons) are acceptable in the USA and are not subject to the same restrictions in Europe as HCFC. Fluorinated gases do not damage the ozone layer like (CFCs) and (HCFCs), however they are powerful greenhouse gases, are generally long-lived and are included in the basket of gases under the Kyoto Protocol. The Kyoto Protocol placed legally binding requirements on signatories to reduce their carbon (and equivalent) emissions to below 1990 levels. Reducing fluorinated gas emissions will contribute towards meeting this obligation.

Europe has a policy to strictly control the use of these fluorinated gases and this makes things very difficult for organisations using these gases. They are revising legislation to take account of this problems and this will make thing even more problematic in the future.

The case for economic and viable use of these in portable extinguishers still remains to be proved. Based on test results and ratings so far achieved, it is unlikely that customers will be willing to pay a premium for a product that performs only as well as the one it replaces.

The silver lining of this situation was that the voluntary withdrawal of portable halon extinguishers by most UK manufacturers at the end of the 1980s provided the impetus for a concentrated research and development effort into the more efficient use of existing agents. As a result, we have a whole new range of both water and foam extinguishers on the market which, through the development of chemical additives, are now far more efficient in firefighting terms.

These extinguishers are more effective when measured by their fire ratings, as well as being smaller (6-litre capacity instead of 9-litre), lighter, easier to handle and easier to use than any of the superseded 9 lt water extinguishers, which were the basic tools industry for many years. Meanwhile, the simultaneous advances in nozzle design produce small droplet sizes that mean that such extinguishers can and do pass the 35kV dielectric test of the European Standard EN3 and are thus much safer to use on fires involving electrical equipment (Although no manufacturer has yet gone the final step stating that such extinguishers are safe for use on fires involving electrical ignition sources.)

Evaluation of Alternatives to Halon Portable Fire Extinguishers

Halon 1211 was a universal extinguisher that could be used on a wide range of flammable materials. The alternatives may not be suitable for all hazards in a particular location and it may be necessary to select more than one type. It is, therefore, essential that staff are trained properly to identify different types of extinguisher and to use them.

Professional advice should be sought where metal fires or fires involving gases may be a hazard.

Streaming Water

Straight stream water is suitable for uses on fires of potentially smouldering materials such as wood, paper and fabrics which may leave glowing embers. Water is very efficient at cooling and so re-ignition is unlikely. The extinguishers have a long water jet that can be used to penetrate deep-seated fires.

This type of extinguisher is unsuitable for use on fires involving liquids or gases and in fact could spread a flammable liquid fuel. They should not be used on powered electrical equipment.

Water Fog (spray)

Water spray extinguishers are most suitable for use on fires of potentially smouldering materials such as wood, paper and fabrics. They are particularly effective on burning embers but are less effective than streaming water on deep-seated fires.

Some water spray extinguishers can be used on electrical equipment but users should ensure that the extinguisher has been tested and certified appropriately.

Water spray extinguishers may offer a very limited capability on fires involving combustible liquids, again appropriate testing and certification, coupled with adequate training of the operator, are essential.

Foam Spray

Aqueous Film Forming Foam (AFFF) spray is a general purpose extinguisher which may be used, with appropriate training, on a wide range of flammable liquids and materials.

Foam spray fire extinguishers can be bought by clicking here.

Foam spray extinguishers are relatively light and can be considered as a replacement for halon 1211 extinguishers in vehicles. They are also suitable, with the correct fire rating, for public service vehicles. Depending on the stream pattern, this type of extinguisher may not be safe for use on electrical equipment.

A more modern version of a Halon alternative,  with FM200 or the greener alternative (with NO ozone emissions) has 3M Novec. Just call JBS Group or email contact@jbsgroup.ie if you/your organization have specific requirements.

Carbon Dioxide

Carbon dioxide (CO 2) may be used safely on a wide range of flammable liquids and materials including live electrical equipment. Care must be taken, however, to avoid contact with the discharge tube and horn to avoid frostbite because these parts get extremely cold in operation.

CO 2 is inexpensive but the containers are relatively heavy and the noise of the discharging gas can be alarming to the untrained user. Once the gas has dispersed re-ignition is a possibility.

Use of CO 2 is particularly recommended in telecommunication rooms and similar applications on board ships.   To see/buy a CO2 extinguisher.

Dry Powder

General-purpose (ABC) dry powder is an extremely effective extinguisher giving rapid knockdown on flammable liquids. It may also be used on potentially smouldering materials. The amount of clean up necessary after use is insignificant when compared to the loss and damage due to the fire.

To see/buy a Dry Powder extinguisher, just click here.

Hydrofluorocarbons (HFCs) and Perfluorocarbons (PFCs).

HFC and PFC agents are restricted in Ireland & the UK for use in portable extinguishers. It is not the policy of the fire industry to select fluorinated gases for use in this sector except in special circumstances and none are generally available in the market at present.

Training

Staff must be provided with such training in the use of fire fighting equipment as appears necessary according to the role they may be expected to play in a fire emergency situation. Training should be provided by a competent person.

Maintenance

Portable fire extinguishers should be maintained at regular intervals and in accordance with the requirements of BS/ EN5306 Part 3.

This page is based on an article by David Bonnett chairman of the FETA

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