Element 11

Question 1

Which types of fire extinguisher are suitable for Class A (wood, paper) fires?

Answer 1

• Water
• Foam
• Dry powder
• Wet chemical

Question 2

What are the common causes of fires within the construction industry?

Answer 2

• Cooking equipment
• Electrical distribution and lighting equipment
• Heating equipment
• Intentional (Arson)
• Hot work (torch, burner)
• Spontaneous combustion
• Smokers’ materials

Question 3

How can heat be transmitted and fire spread?

Answer 3

• Direct contact
• Conduction
• Radiation
• Convection

Question 4

Compartmentation is a means of minimising fire spread in buildings. True or false?

Answer 4

True. One of the basic techniques in minimising the spread of fire is to separate a building into “compartments”. The aim is to ensure that there is a fire resisting barrier between compartments.

Question 5

Wood possesses certain features that allow it to provide satisfactory performance in most building fires. True or false?

Answer 5

rue. One of these is that it is not easily ignitable, but the most important property of wood is the formation of char after ignition. Charred wood is likely to be found in nearly all structural fires. It is the solid residue (mainly carbon) from the decomposition of wood. It shrinks as it forms and develops cracks and blisters. In combination with a low thermal conductivity, and a protective layer of char, heavy timber sections can provide excellent fire resistance and therefore continue to be used.

Question 6

Give examples of possible (fire) ignition sources on a construction site.

Answer 6

• Smokers’ materials
• Naked flames, e.g. gas or liquid-fuelled open-flame equipment
• Those deliberately introduced (arson)
• Plant and equipment, e.g. fuel and vehicle exhausts
• Electrical - faulty or misused electrical equipment
• Poor electrical installations, e.g. overloads, heating from bunched cables and/or damaged cable
• Hot processes / hot work, e.g. welding
• Light fittings and lighting equipment, e.g. temporary lighting, halogen lamps too close to stored products
• Electrical, gas- or oil-fired heaters (fixed or portable), room heaters in temporary office accommodation or welfare cabins
• Heat sources, such as gas, electric, cooking equipment
• Friction-generated heat and sparks from mechanical equipment such as disc cutters
• Static charge from mechanical equipment
• Spontaneous ignition and self-heating, e.g. oil-soaked rags, paint scrapings
• Lightning and refracted sunlight

Question 7

Heat detectors should never be used in a kitchen. True or false?

Answer 7

False. Heat detectors are preferred to smoke detectors, as smoke detectors would regularly (false) alarm as a result of the smoke produced from cooking.