CSCS Test Practice

🔥 Fire Prevention & Control

Fire Prevention & Control

Fire on a construction site can spread quickly, threatening lives and property. Under the Regulatory Reform (Fire Safety) Order 2005, fire safety must be managed through a suitable fire risk assessment. The starting point is the fire triangle: a fire needs three elements to burn — heat (a source of ignition), fuel (anything combustible) and oxygen (from the air). Remove any one and the fire goes out. Prevention means keeping these three apart.

Most site fires are avoidable. Common causes include hot works, electrical faults, smoking, and the careless storage of combustible waste. Good housekeeping is the simplest control: remove rubbish and offcuts regularly, keep escape routes clear, store materials tidily and never let waste build up against the building or in stairwells.

Hot works — welding, cutting, grinding and using a blowtorch — are a major ignition source and should be controlled by a hot works permit. The permit sets out precautions, removes nearby combustibles, requires extinguishers to hand, and demands a fire watch kept during the work and for a period after completion, because smouldering materials can ignite long after the work has stopped.

Store flammable liquids and gases carefully. LPG and other flammable gas cylinders should be kept outside in secure, ventilated cages, upright, away from ignition sources and drains. Flammable liquids belong in proper bins or stores, and combustible materials kept to the minimum needed.

Match the extinguisher to the class of fire:

Know your site fire arrangements: detection and alarms, clear escape routes and the assembly point. On discovering a fire, raise the alarm immediately, only tackle a small fire if trained and safe to do so, then evacuate calmly by the nearest route — never use lifts — and report to the assembly point so everyone can be accounted for.

Finally, prevent arson: secure the site at the end of each day, lock away fuels and cylinders, remove waste that could be set alight, and ensure perimeter fencing, lighting and security are maintained.

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Sample questions (35)

1. The 'fire triangle' shows the three things a fire needs to burn. What are they?

  1. Heat, fuel and oxygen
  2. Smoke, sparks and fuel
  3. Heat, water and air
  4. Fuel, foam and pressure

A fire needs heat (a source of ignition), fuel (something to burn) and oxygen; removing any one will put the fire out. Source: Regulatory Reform (Fire Safety) Order 2005; HSE guidance

2. If you remove just one side of the fire triangle, what happens to the fire?

  1. It will go out
  2. It will burn hotter
  3. It will spread faster
  4. Nothing changes

Fire needs all three elements (heat, fuel and oxygen) at once; take any one away and the fire cannot continue to burn. Source: Regulatory Reform (Fire Safety) Order 2005; HSE guidance

3. In the fire triangle, which of these would be classed as the 'fuel'?

  1. Timber off-cuts and packaging
  2. A naked flame
  3. The air around you
  4. A spark from a grinder

Fuel is anything that will burn, such as timber, packaging, paper or solvents; flames and sparks are heat sources and air provides oxygen. Source: Regulatory Reform (Fire Safety) Order 2005; HSE guidance

4. Which side of the fire triangle does a fire blanket mainly remove when it is placed over a small fire?

  1. Oxygen
  2. Fuel
  3. Heat
  4. Smoke

A fire blanket smothers the fire, cutting off the supply of oxygen so the fire cannot continue to burn. Source: Regulatory Reform (Fire Safety) Order 2005; HSE guidance

5. When water is used to put out a fire involving wood and paper, which side of the fire triangle is it mainly removing?

  1. Heat
  2. Oxygen
  3. Fuel
  4. Pressure

Water cools the burning material, removing the heat from the fire triangle so the fire can no longer sustain itself. Source: Regulatory Reform (Fire Safety) Order 2005; HSE guidance

6. You notice flammable solvents and waste packaging building up next to a heater in a site cabin. In fire triangle terms, what is the main problem?

  1. Fuel and a heat source have been brought close together
  2. There is too much oxygen in the cabin
  3. The fuel has been removed from the area
  4. The heat source has been isolated

Storing fuel (solvents and packaging) next to a heat source brings two sides of the fire triangle together, creating a serious fire risk. Source: Regulatory Reform (Fire Safety) Order 2005; HSE guidance

7. Good housekeeping helps prevent fires on site. Which fire triangle element does clearing away timber off-cuts, packaging and other waste mainly reduce?

  1. Fuel
  2. Oxygen
  3. Heat
  4. Smoke

Removing combustible waste takes away potential fuel, so even if a heat source occurs there is less for a fire to feed on and spread. Source: Regulatory Reform (Fire Safety) Order 2005; HSE guidance

8. A hot works permit requires the area to be cleared of combustible materials before cutting or grinding begins. Which two sides of the fire triangle does this control mainly address?

  1. The heat from the work and the fuel nearby
  2. The oxygen and the smoke
  3. The fuel and the oxygen only
  4. The heat and the oxygen only

Hot works create a heat/ignition source, so removing nearby combustibles takes away the fuel, leaving the heat without anything to ignite. Source: Regulatory Reform (Fire Safety) Order 2005; HSE guidance

9. Why is simply reducing the oxygen supply often a difficult way to control a fire in an open outdoor work area?

  1. Oxygen is present in the surrounding air everywhere
  2. Oxygen is not part of the fire triangle outdoors
  3. Fuel cannot burn in the open air
  4. Heat sources are not present outdoors

Outdoors, oxygen is freely available from the air all around, so removing heat or fuel is usually the more practical way to control or prevent fire. Source: Regulatory Reform (Fire Safety) Order 2005; HSE guidance

10. Which type of fire extinguisher is best for a fire involving wood, paper and textiles?

  1. Water
  2. Carbon dioxide (CO2)
  3. Dry powder for live electrics only
  4. A fire blanket alone

Wood, paper and textiles are Class A materials, and a water extinguisher cools them effectively to put out the fire. Source: Regulatory Reform (Fire Safety) Order 2005; HSE guidance

11. A small fire breaks out in live electrical equipment in a site office. Which extinguisher should you use?

  1. Carbon dioxide (CO2)
  2. Water
  3. Foam
  4. A bucket of sand and water

Water and foam conduct electricity and could give you a shock, so a CO2 extinguisher is the safe choice for live electrical equipment. Source: Regulatory Reform (Fire Safety) Order 2005; HSE guidance

12. Why must you NEVER use a water extinguisher on a fire involving live electrical equipment?

  1. Water conducts electricity and you could get an electric shock
  2. Water makes electrical fires burn hotter
  3. Water is only for oil fires
  4. Water removes the fuel too slowly

Water conducts electricity, so using it on live equipment risks a serious or fatal electric shock to the person holding the extinguisher. Source: Regulatory Reform (Fire Safety) Order 2005; HSE guidance

13. Which extinguisher is suitable for a fire involving flammable liquids such as petrol, diesel or paint thinners?

  1. Foam
  2. Water
  3. A wet cloth
  4. A jet of plain water

Flammable liquids are Class B fires; foam forms a blanket over the liquid surface to smother the flames, whereas water would spread the burning liquid. Source: Regulatory Reform (Fire Safety) Order 2005; HSE guidance

14. What does the class 'A' of fire refer to?

  1. Fires involving solid materials such as wood, paper and cloth
  2. Fires involving flammable liquids
  3. Fires involving flammable gases
  4. Fires involving cooking oils

Class A fires involve ordinary combustible solids like wood, paper and textiles, which are usually best tackled with water. Source: Regulatory Reform (Fire Safety) Order 2005; HSE guidance

15. A fire involving flammable liquids belongs to which class?

  1. Class B
  2. Class A
  3. Class C
  4. Class D

Class B covers flammable liquids such as petrol, diesel, oils and solvents, which are usually tackled with foam, CO2 or dry powder. Source: Regulatory Reform (Fire Safety) Order 2005; HSE guidance

16. Which type of extinguisher can be used on most classes of fire, including flammable liquids and live electrical equipment, and is often called a 'multi-purpose' extinguisher?

  1. Dry powder
  2. Water
  3. Foam
  4. Wet chemical

Dry powder is a multi-purpose extinguisher effective on solids, liquids, gases and live electrics, though it leaves a messy residue and reduces visibility. Source: Regulatory Reform (Fire Safety) Order 2005; HSE guidance

17. How is a CO2 (carbon dioxide) extinguisher usually identified?

  1. By a black label or band
  2. By a blue label or band
  3. By a cream label or band
  4. By a red label or band

Under the UK colour-coding system extinguisher bodies are red, with a black panel indicating a CO2 extinguisher. Source: BS EN 3 extinguisher colour coding; HSE guidance

18. Under the UK colour-coding system, what colour panel or label identifies a foam extinguisher?

  1. Cream
  2. Black
  3. Blue
  4. Green

All extinguisher bodies are red, with a coloured panel showing the type; cream indicates foam. Source: BS EN 3 extinguisher colour coding; HSE guidance

19. What colour panel or label is used to identify a dry powder extinguisher?

  1. Blue
  2. Cream
  3. Black
  4. Green

Dry powder extinguishers are identified by a blue panel on the red body under the UK colour-coding system. Source: BS EN 3 extinguisher colour coding; HSE guidance

20. You discover a small fire in a waste skip full of wood and cardboard. Which extinguisher is the most suitable first choice?

  1. Water
  2. Carbon dioxide (CO2)
  3. Wet chemical
  4. A foam extinguisher kept for fuel stores

Wood and cardboard are Class A materials, so a water extinguisher is the most suitable and effective first choice for cooling the fire. Source: Regulatory Reform (Fire Safety) Order 2005; HSE guidance

21. A CO2 extinguisher has just been used on a fire in live electrical equipment, but the equipment is still hot. Why might the fire re-ignite?

  1. CO2 has no cooling effect, so hot material can reignite once the gas disperses
  2. CO2 adds fuel to the fire
  3. CO2 increases the oxygen around the fire
  4. CO2 makes the metal conduct electricity

CO2 works by removing oxygen but does little to cool the fuel, so if hot material remains the fire can re-ignite once the gas clears. Source: Regulatory Reform (Fire Safety) Order 2005; HSE guidance

22. Which extinguishers are generally suitable for a fire involving flammable gases such as propane or butane (a Class C fire)?

  1. Dry powder, after isolating the gas supply if it is safe to do so
  2. Water only
  3. Foam only
  4. Wet chemical only

Dry powder can tackle Class C flammable gas fires, but the priority is to isolate the gas supply where it is safe, as burning gas left flowing can lead to an explosion. Source: Regulatory Reform (Fire Safety) Order 2005; HSE guidance

23. Why is a CO2 extinguisher often preferred over foam for live electrical equipment?

  1. CO2 does not conduct electricity and leaves no residue on the equipment
  2. CO2 cools the equipment far better than foam
  3. CO2 is the only extinguisher allowed indoors
  4. CO2 adds oxygen to help the fire burn out safely

CO2 is non-conductive and leaves no residue, making it safer for live electrical equipment than foam, which conducts electricity and causes damage. Source: Regulatory Reform (Fire Safety) Order 2005; HSE guidance

24. You try to tackle a small fire with an extinguisher but it is not going out and smoke is building up. What should you do?

  1. Stop, leave the area, raise the alarm and get out to the assembly point
  2. Keep trying with the same extinguisher until it is empty
  3. Open windows to let more air in
  4. Go and look for a bigger extinguisher on your own

If a fire is not quickly controlled you should not put yourself at risk; raise the alarm, leave by the escape route and go to the assembly point. Source: Regulatory Reform (Fire Safety) Order 2005; HSE guidance

25. Before using any fire extinguisher on a fire, what is the most important thing to do first?

  1. Raise the alarm so others know about the fire
  2. Open all the doors and windows
  3. Find out who started the fire
  4. Move the extinguisher to a safe store

Raising the alarm first ensures everyone can evacuate and the fire service can be called, even if your attempt to use the extinguisher fails. Source: Regulatory Reform (Fire Safety) Order 2005; HSE guidance

26. A fire needs three things to start and keep burning. Which combination makes up the 'fire triangle'?

  1. Heat, fuel and oxygen
  2. Water, fuel and smoke
  3. Heat, water and oxygen
  4. Fuel, smoke and sparks

The fire triangle is heat (a source of ignition), fuel and oxygen; removing any one of the three will put the fire out. Source: Regulatory Reform (Fire Safety) Order 2005

27. Which of these is one of the most common causes of fires on construction sites?

  1. Build-up of combustible waste and rubbish
  2. Storing tools in a locked container
  3. Wearing a hard hat in a high-risk area
  4. Using 110V power tools

Accumulations of combustible waste, packaging and rubbish provide ready fuel and are a leading cause of site fires, which is why good housekeeping is essential. Source: HSE guidance / Fire prevention on construction sites (HSG168)

28. Why does good housekeeping help to prevent fires on site?

  1. It removes the build-up of fuel such as waste and packaging
  2. It increases the amount of oxygen in the air
  3. It makes alarms louder
  4. It keeps fire extinguishers cooler

Keeping the site tidy and clearing combustible waste removes the fuel side of the fire triangle, reducing both the chance of a fire and how fast it can spread. Source: HSE guidance / Regulatory Reform (Fire Safety) Order 2005

29. You are about to carry out 'hot work' such as cutting, grinding or welding. What document should normally be in place before you start?

  1. A hot work permit
  2. A holiday request form
  3. A delivery note
  4. A timesheet

Hot work is a major ignition source, so it should only be done under a hot work permit that sets out the precautions, fire watch and checks needed. Source: HSE guidance / Regulatory Reform (Fire Safety) Order 2005

30. After finishing hot work such as grinding or welding, what is the best practice to reduce the risk of a delayed fire?

  1. Keep a fire watch on the area for a period after the work finishes
  2. Leave site immediately to save time
  3. Cover the hot area with combustible sheeting
  4. Switch off the alarm so it does not sound by accident

Hot work can leave smouldering materials that catch fire later, so a fire watch should continue for a set time after the work to spot and deal with any smouldering before leaving. Source: HSE guidance / Regulatory Reform (Fire Safety) Order 2005

31. Where should flammable liquids such as petrol, thinners and solvents be kept on site?

  1. In a properly marked, secure store away from ignition sources
  2. Next to the welding bay for convenience
  3. In an open skip with other waste
  4. Inside the site canteen

Flammable liquids give off vapours that ignite easily, so they must be stored in a suitable, well-ventilated and secure store kept away from any ignition sources. Source: HSE guidance / Dangerous Substances and Explosive Atmospheres Regulations 2002

32. Which of the following is the safest way to deal with flammable rubbish and offcuts during the working day?

  1. Remove it regularly to a designated waste area away from the work
  2. Pile it up in the corner of the room until the job is finished
  3. Burn it on site whenever it builds up
  4. Store it under the temporary electrical supply

Frequently clearing combustible waste to a designated area away from work activities prevents a large build-up of fuel and keeps escape routes clear. Source: HSE guidance / Fire prevention on construction sites (HSG168)

33. You notice that an electrical extension lead is damaged with the inner wires showing. What should you do?

  1. Take it out of use and report it so it can be repaired or replaced
  2. Wrap it in tape and carry on using it
  3. Leave it for the next shift to deal with
  4. Coil it up and put it back in the store for someone else to use

Damaged leads can cause sparks, short circuits and fires, so they must be taken out of use and reported; only a competent person should repair electrical equipment. Source: Electricity at Work Regulations 1989

34. Why are LPG (liquefied petroleum gas) cylinders treated as a serious fire and explosion risk on site?

  1. The gas is highly flammable and heavier than air, so leaks can collect at low level
  2. The cylinders are too heavy to move safely
  3. The gas is completely harmless but the cylinders are expensive
  4. LPG cools the air and prevents fires

LPG is highly flammable and its vapour is heavier than air, so any leak can pool in low areas such as trenches and basements and ignite, which is why cylinders must be stored and used carefully. Source: HSE guidance / Dangerous Substances and Explosive Atmospheres Regulations 2002

35. How should LPG and other gas cylinders normally be stored when not in use?

  1. Upright, secured and in a well-ventilated outdoor area
  2. Lying flat inside a closed cabin
  3. In the bottom of a deep excavation
  4. Stacked next to the hot works area

Gas cylinders should be stored upright, secured against falling and in a well-ventilated outdoor area away from ignition sources to prevent leaks collecting and igniting. Source: HSE guidance / Dangerous Substances and Explosive Atmospheres Regulations 2002

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