IT1 U06 - Safety Signs and Fire Extinguishers

CGLI 2330 Certificate in Electrotechnical Technology Level 2 Inst Tech: Unit 201 – Working Effectively & Safely in an Electrotechnical Environment

Unit 06 - Safety Signs and Fire Extinguishers

The College at Clacton Unit 06 Page 1 August 2011

Safety Signs & Fire Extinguishers

Unit Aims

By the end of the unit participants should be able to:

Identify types and meaning of safety signs a) Warning b) Advisory c) Mandatory d) Prohibition

(Syllabus Reference: 1.1.08)

Identify types and applications for fire extinguishers a) Water b) Powder c) Foam d) Gas

(Syllabus Reference: 1.1.11)

Safety Signs

‘The Health and Safety (Safety Signs and Signals) Regulations 1996’ states that all new Health and Safety Signs must contain pictorial symbols in addition to text. Other requirements contained in these regulations include:

if a hazard cannot be adequately controlled by any other means then it must be marked with a safety sign

every employer must ensure that their employees are trained in the meaning of safety signs

any emergency escape route and fire fighting equipment must have their location identified with safety signs

Most workplaces have safety signs and posters to alert you of any dangers. These are grouped into four categories:

warning signs

information signs

mandatory signs

prohibition signs

and in addition there are location signs for fire fighting equipment.

For more information see page 24 of ‘Electrical Installations Level 2 2330 Technical Certificate’ – revised for the 17th Edition IEE Wiring Regulations (ISBN 978 0 435401 09 2).




Warning signs

Warning signs are triangular and yellow with a black border. They mean CAUTION, RISK OF DANGER or HAZARD AHEAD.

Information signs

Safe condition signs are rectangular and white on a green background and indicate the correct place to go or the correct action to be taken in an emergency. They give information about safe conditions.

You are likely to find extra information included with any of the safety signs, such as the type of first aid available, the particular type of eye protection required, the clearance height of an obstacle etc.

Mandatory signs

Mandatory signs are white on a blue background, circular and mean YOU MUST DO.

Prohibition signs

Prohibition signs are circular in shape and have a crossbar through the centre and mean STOP or DO NOT. They are red on a white background and must be obeyed.

Fire Fighting Equipment signs

The Health and Safety (Safety Signs and Signals) Regulations require the location of all fire fighting equipment to be marked in red. Typical signs are shown right.




Fire Extinguishers A fire is a chemical reaction which will continue if fuel, oxygen and heat are present. To eliminate a fire one of these components must be removed. This is often expressed by means of the ‘fire triangle’ shown below; all three sides must be present for a fire to burn.

Fuel

Fuel is found in the construction industry in many forms: petrol and paraffin for portable generators and heaters; bottled gas for heating and soldering. Most solvents are flammable. Rubbish also represents a source of fuel: off-cuts of wood, roofing felt, rags, empty solvent cans and discarded packaging will all provide fuel for a fire.

To eliminate fuel as a source of fire, all flammable liquids and gases should be stored correctly, usually in an outside locked store. The working environment should be kept clean by placing rags in metal bins with a lid. Combustible waste material should be removed from the work site or burned outside under controlled conditions by a competent person.

Oxygen Oxygen is all around us in the air we breathe, but can be eliminated from a small fire by smothering with a fire blanket, sand or foam. Closing doors and windows (but not locking them) will limit the amount of oxygen available to a fire in a building and help to prevent it spreading.

Most substances will burn if they are at a high enough temperature and have a supply of oxygen. The minimum temperature at which a substance will burn is called the ‘minimum ignition temperature’ and for most materials is considerably higher than the surrounding temperature. However, a danger does exist from portable heaters, blow torches and hot air guns which provide heat and can cause a fire by raising the temperature of materials placed in the path above the minimum ignition temperature. A safe distance must be maintained between heat sources and all flammable materials.




Heat

Heat can be removed from a fire by dousing with water, but water must not be used on burning liquids since the water will spread the liquid and the fire. Some fire extinguishers have a cooling action which removes heat from the fire.

Fire Fighting

Fires in industry damage property and materials, injure people and sometimes cause loss of life. Everyone should make an effort to prevent fires, but those which do break out should be extinguished as quickly as possible.

In the event of a fire you should (if possible and safe to do so):

Raise the alarm

Turn off machinery, gas and electricity supplies in the area of the fire

Close windows and doors but without locking or bolting them

Remove combustible material and fuels away from the path of the fire, if the fire is small, and this can be done safely

Attack small fires with correct extinguisher.

Only attack a fire if you can do without endangering your own safety in any way. Those not involved in fighting the fire should walk to a safe area or assembly point.

Classification of Fires

Fires are divided into four classes or categories according to the fuel involved:

Class Fuels Involved

Class A Wood, paper and textiles, etc.

Class B Liquid fires such as paint, petrol and oil.

Class C Fires involving gas or spilled liquefied gas.

Class D Very special types of fire involving burning metal.

Electrical fires do not have a special category because once started, they can be identified as one of the four above types.




Fire Extinguishers

Fire extinguishers are for dealing with small fires and different types of fire must be attacked with a different type of extinguisher. Using the wrong type of extinguisher could make matters worse. For example, water must not be used on a liquid fire or a fire involving electricity. The normal procedure when dealing with electrical fires is to cut off the electricity supply and use an extinguisher which is appropriate to whatever is burning. The chart below shows the correct type of extinguishers to be used on three of the categories of fire:

For more information see pages 32 to 33 of ‘Electrical Installations Level 2 2330 Technical Certificate’ – revised for the 17th Edition IEE Wiring Regulations (ISBN 978 0 435401 09 2).

Documents

IT1 U06 - Safety Signs and Fire Extinguishers