Fire Extinguishers

Do you know the most common one?

The most common, and most practical portable fire extinguisher in the maritime industry is…

…the Dry Chemical Powder is the most common type used in Australia.
They are also known as a DCP fire extinguisher.

DCP fire extinguishers are easily distinguishable by the white band that is around the extinguisher cylinder. They also come in two different types which are ABE (recommend) or BE type.

What fires can dry chemical extinguishers be used on?

DCP extinguishers are extremely effective and versatile and with 2 types they can be used on the following fires:

– ABE Type

• Class A Fires: paper, cardboard, wood, fabrics, etc.
• Class B Fires: flammable liquid fires, petrol, diesel, oil, etc.
• Class E Fires: electrical fires, computers, photocopiers, switchboards, etc.

– BE Type:

• Class B Fires: flammable liquid fires, petrol, diesel, oil, etc.
• Class E Fires: electrical fires, computers, photocopiers, switchboards, etc.

How does a Dry Powder Chemical extinguisher work?

Each type of extinguisher works by attempting to remove one of the elements that are needed for a fire to flourish. Most ABE extinguishers are filled with monoammonium phosphate which has the ability to flow easily and melt so it continues to cover the flames as it moves over the fire.

BE powder does not melt so it is ineffective against class A fires.

ADVANTAGES

• Quick Knockdown – Dry powder, when correctly applied and at the required application rate, has the ability to ensure an initial quick knockdown of the fire.
• Non-Conductor of Electricity – Dry powder can safely be used at incidents where it is known or suspected that ‘live’ electrical equipment is present.
• Good on Running Fuel Fires – Owing to its fire extinguishing action, dry powder, when used in conjunction with foam sprays, can be extremely effective when used on running fuel fires.
• Creates No Thermal Shock – Because the application of dry powder onto hot metal does not cause thermal shock, it is particularly useful for dealing with fires involving undercarriage assemblies.
• Good Heat Shield – The discharge of dry powder creates an effective shield against radiated heat. In cases where large quantities of powder are discharged, this has the potential to shield surrounding structures and personnel from the damaging effects of the fire.
• Wide Range Of Use – Dry powder extinguishers can be used on class A,B and C Fires.
• Wide Temperature Range – Typically can be used between -20ºC to +60ºC.
• Mass for mass the most effective fire-fighting medium.

DISADVANTAGES

• Visibility Problems – The application of dry powder and generation of a dense powder cloud will dramatically reduce the visibility of the operator so they may not be able to use vision to judge the effectiveness of the powder on the fire or may jeopardise escape in a fire.
• Can Cause Breathing Problems – If dry powder is inhaled it can irritate the respiratory organs. Whilst short term exposure is not considered to be harmful, repeated inhalation should be avoided.
• Leaves a Residue – Dry powder is a very messy extinguishing agent that will leave behind a residue that is corrosive to certain materials and because it is a fine powder it can also be abrasive. Thoughtless use may lead to the powder causing more damage than the fire itself, using dry powder fire extinguishers in kitchens or offices as powder can contaminate food and inhibit the use of electrical components such as keyboards if discharged. Because of the properties of powder being very light and easily carried through the atmosphere dry powder extinguishers when discharged can risk contamination over a wide area.
• Poor Post Fire Security – Due to the smothering and chemical interference effect of dry powder, it will only remain effective whilst it is present in the atmosphere above the fuel. Because it is a cloud of fine powder, particles of it can easily be dispersed by the wind, giving a very real danger of rapid re-ignition of fuel.
• Can Break Down Foam Blanket – The use of dry powder close to an area covered by a foam blanket may lead to the foam breaking down more quickly.
• Usage & Location – Because of the disadvantages above dry powder extinguishers should only be found in industrial/residential settings and where no alternative fire extinguisher mediums are suitable.
• Limit of use, not to be used on class D or F fires

Shorlink’s Recommendation

We highly recommended that you remove all DCP extinguishers from the bracket and turn them upside down then give them a shake as the powder can pack down in the base of the extinguisher. If this occurs it may not work properly or at all! Do this every 1 – 2 months with all DCP extinguishers.

DCP extinguishers are recommended for use in all commercial and recreational vessels, on marinas and in offices and factories.

Tip

Number one tip and one that came up in a recent training session was that if used or even tested by pulling the handle/trigger the extinguisher will not work again, even hours after being tested.

If you have to use a DCP extinguisher remove it from its bracket, turn it upside down, give it a quick shake then test it by pilling the handle briefly. It’s not a good look approaching a fire, going to use the extinguisher and it doesn’t work!

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