CSCS Test – Powder and Foam Extinguishers
Other types of extinguishers which you may be questioned about in the cscs test are Powder and foam. in order to pass your test and get your card you will need to understand and be able to answer questions on the different uses of each.
CSCS Revision Dry Powder Extinguishers
The following cscs revision notes are well worth remembering. There is a very good chance that there will be questions in your cscs test fire safety section about them.
Dry powder extinquishers are coloured Blue (remember powder blue)
They are safe to use on solids and liquids like paint, petrol, oil and electrical fires.
They are not safe on chip pan fires as there is a danger of blowing burning fat or oil about. It quickly extinguishes the fire but does not soak in or penetrate, so it is possible that the fire could reignite. An example of where re-ignition could occur is in electrical or furniture fires.
How to use: Point at the bottom of the flames and move rapidly across to the other side in a sweeping motion to put the fire out. Repeat if the flames come back.
The powder acts as a buffer to the heat and cause the flames to die out and stopping the fire continuing.
CSCS Revision – Special Powder Extinguishers
These are used for burning metals and you must be trained to use them.
Metal fires are different from other fires. Metals like aluminium, lithium and magnesium will burn, especially when in powder form. Water MUST NOT be used on these fires.
Special powder extinguishers can be used on metal fires and three powders are used for these fires, copper, Sodium Chloride, and graphite. The sodium chloride powder extinguisher is not recommended to be used on lithium fires.
The powder is sprayed at low speed through an extended spray lance to smother the fire. This stops the metal powder from being spread. The powder will form a layer which keeps and oxygen out and stops the fire.
CSCS Revision – Foam Fire Extinguishers
These are coloured CREAM. ( Think of spray whipped cream to remember, its a bit like foam)
There are two types of foam extinguisher, standard and AFFF (Aqueous Film Forming Foam)
These are mainly for use on liquid fires for example paint and oil and work by floating on top of the liquid and cutting off the flames from their source of fuel.
They are also prevent the heat of the flames from evaporating off more of the liquid to burn. Foam extinguishers are not to be used on electrical fires.
Although they are not recommended, Foam Extinguishers can also be used on Class A fires (wood rubber plastic etc.)
If you use this type of extinguisher on a container fire you must not point the extinguisher directly at the liquid.
The best method is to point it at the side of the container and let the foam run down and float over the surface. You can also aim it at something overhanging the fire and let the foam run down.
Important CSCS Revision Note
Remember that a fire needs 3 things to burn, OXYGEN + FUEL + HEAT. All extinguishers work by removing one or more of these requirements. Foam and powders tend to work mainly by excluding oxygen and in the case of the foam extinguisher mentioned above, by preventing the liquids from evaporating and producing more fuel for the fire.
Try to remember the colours for each of the extinguishers, when you take your CSCS Test you will definitely be asked one or more questions on Fire extinguishers. Check out the rest of the site for more free online CSCS Revision and CSCS Revision questions.