Showing posts with label Element 7. Show all posts
Showing posts with label Element 7. Show all posts

Tuesday 15 April 2008

Typical Examination Questions based on Element 7

1.

(a) Explain the methods of heat transfer that can cause the spread of fire.

(b) Outline the main requirements of a safe means of escape from a building.

(8)

(12)

(a) Methods are Conduction (e.g. through a plastic coffee cup), convection (e.g. up a chimney), radiation (e.g. from a fire) and direct burning (e.g. of any fuel such as wood)

(b) Emphasis on fire resistant materials for escape route walls, ceilings and doors. Easy exit provisions with doors opening in direction of travel and self-closing. Notices identifying, and lighting of, escape routes. Good housekeeping on routes to ensure no obstacles and no flammable substances on routes. Distances form workstations into an escape route. A safe assembly point. Fire alarm and extinguisher stations on route towards safe routs.

2.

(a) Outline the main factors to be considered in the siting of fire extinguishers.

(b) Outline the inspection and maintenance requirements for fire extinguishers in a workplace.

(4)

(4)

(a) Accessibility, proximity to exits, travel distances, situated at fire points, protection when required from weather or other sources of damage.

(b)


Inspection should be routinely carried out to ensure extinguishers are in place, have not been discharge, damaged, have pins missing or, because of a change in local conditions or work are unsuitable for the fires they are meant to deal with.

Maintenance is something more extensive and usually involves annual tests by a competent person according to the manufacturer's instructions in order to ensure the integrity of the extinguisher, with the removal and replacement of equipment found faulty.

3.

List EIGHT features of a safe means of escape from a building in the event of a fire.

(8)

Issues include; at least two escape routes available in two directions from work-areas taking account of escape distances from workplace to protected zone. The fire resistant integrity of escape routes. The ability of fire doors to be easily opened in direction of escape and to self close. The need to ensure escape routes are kept free from obstructions. Appropriate siting and marking of assembly points. Fire escape notices of the appropriate type. Lighting of escape routes. Suitability for people with special needs.

4.

(a) Outline TWO advantages and TWO disadvantages of using hose reels as a means of extinguishing fires.

(b) Outline the main factors to consider in the siting of hose reels.

(4)


(4)

(a) Advantages

(i) A continuous supply of water that is of a greater force and quantity than an extinguisher has.

(ii) User does not need to be close to the fire.

Disadvantages

  1. Effort required to position and use a hose,
  2. The hose can compromise smoke barriers by keeping doors ajar and water is not suitable for use on all fires.

(b) Issues are; accessibility (should be on, or adjacent to, an escape route e.g. on a stairwell). Recessing where possible into walls to avoid blocking escape routes. Possible sealed hole from hose to pass from stairwell into offices etc. Positioned to give maximum coverage in terms of the length of hose, where frost will not cause the water to freeze and they will not be subject to misuse or vandalism.

5.

(a)
With reference to the fire triangle, outline TWO methods of extinguishing fires.

(b)
State the ways in which persons can be harmed by fire in work premises.

(4)


(4)

(a) Examples: starvation (removing the fuel). Smothering (Eliminating oxygen). Cooling (pouring water on to the fire) or by interfering chemically with the combustion process.

(b) Harmed by being burnt, inhaling smoke, by depleted oxygen supply, falling parts of a building or by being crushed or suffering some other injury in trying to escape.

6.

(a)
Identify FOUR types of ignition sources that may lead to a fire in the workplace.

(b)
Outline ways of controlling each of the ignition points identified in (a).

(4)


(4)

(a) Ignition sources include: Smoking, hot work and surfaces, electricity, reactive chemicals, and arson.

(b) Control could include:

Smoking - ban or restriction on smoking.

Hot work and surfaces -ensuring no combustible materials are in the vicinity of hot work.

Electricity - ensuring no over-loading of circuits and proper care and maintenance of electrical equipment.

Reactive chemicals - control through work practices and procedures including storage.

Arson - having good security arrangements including restriction of strangers in building and diligent supervision.



Saturday 12 April 2008

Fire & Fire Safety

Legislation

The Regulatory Reform (Fire Safety) Order 2005 is Law.

In Scotland, The Fire (Scotland) Act 2005

In Northern Ireland the Fire Precautions (Workplace) Regulations 1997/1999


The cornerstone of the regulations is fire risk assessment. through this the following need to be considered

* Preventing fire occurring
* Preventing fire spreading (design of premises as well as fire fighting)
* Ensuring people are adequately protected if a fire occurs - includes employees, visitors, neighbours and fire service personnel.

Emphasis is on the employer being responsible for managing risks from fire. To achieve this they need to have competence to assess and control the risks.

Fire - preventing

The main ways of preventing fire are by controlling fuels and ignition sources. In particular, suitable storage for highly flammable materials and selection of equipment in flammable hazardous areas.

Oxidising agents need to be handled carefully and kept away from flammable materials.

The possibility of arson must be considered, and keeping sites secure and free from rubbish and other flammable items is important.

Fire - detection and escape

People need to know there is a fire so that they can escape. Options for detection include:
* Smoke,
* Flame (UV)
* Heat
* Manual (e.g. break glass).

Factors that affect ease of escape include:
* Number of fire escapes (ideally always more than two independent safe routes from any location);
* Distance to exit
* Clutter on route
* Fire integrity of escape route - fire doors that close automatically
* Ability to open fire doors - must not be locked, open outwards
* Signage
* Emergency lighting
* (Safe) assembly points
* Knowledge of procedures - staff and visitors
In general, do not use lifts. Need to make provision for disabled people including physical, visual and deaf (cannot hear alarms).

Fire - extinguishing

Fires can be extinguished by eliminating any one side of the fire triangle. This usually involves cooling, creating a barrier between fuel and oxygen, using a chemical that interfere with fire process, or replacing oxygen with another non-flammable gas.
Types of extinguishing device include:
* Water from extinguisher, hose, sprinkler, deluge (cools)
* Foam (cools and seals over fuel) - good for liquids
* Power (chemical interference)
* Carbon dioxide (displaces air/oxygen) - good for electrical fires
* Fire blanket (smothers) - chip pans

Fire - spreading

Fire can spread by:
* Conduction - heat moving through solid material;
* Convection - heat moving through a fluid or gas (i.e. hot air rising)
* Radiation - emission of infra-red energy that can then be absorbed and cause items to get hot

Fire - sources of ignition

Include
* Sparks
* Flame
* Hot surfaces
* Friction
* Electricity (including static)
* Smoking material (e.g. cigarettes)

Fire - fuels

Include
* Solids
* Liquids
* Gas and vapour
* Oxidising agents - react with other substances to create flammable conditions, possibly without oxygen being present

Fire - hazards

Include
* Heat - causing burns
* Smoke and fumes
* Oxygen depletion
* Structural damage to buildings etc.

Fire

For a fire to occur you must have all three sides of the fire triangle present, namely

* Fuel
* Oxygen
* Heat

Eliminating any will prevent a fire or extinguish one that is already going.


Source Health and Safety 2008 - Nebosh General Certificate

Element 7, Fire - hazards and control

Element covers:

  • Basic fire principles, hazards and risks in the workplace
  • Fire prevention and prevention of fire spread
  • Fire detection, fire alarm and firefighting equipment
  • Means of escape
  • Evacuation of the workplace

Fire and fire safety which on any construction site is a major concern, The element describes the hazards which can cause fires, such as poor housekeeping, not enforced smoking policies, poor equipment maintenance, and the storage of flammable materials.

It is essential that a construction site has good housekeeping policies in place this effects most activities and can lead to becoming a fire risk if not enforced.

Smoking around flammable materials, and the storage of such couple with bad housekeeping can lead to quite serious fire risks. Flammable materials such as wood paper not just liquids should be stored in a safe and tidy manner, with the appropriate fire fighting equipment near to hand.

The storage of flammable liquids has separate legislation and if you are storing these in any significant quantity, you should look into this further.

Electrical fire are not categorised as a class of fire as others are (see table below) but electricity is a cause of many fires, therefore the correct use and maintenance of supplies and equipment are essential.

Class

Fuel/Heat source

Class A

Ordinary combustibles

Class B

Flammable liquids

Class C

Flammable gases

Class D

Combustible metals

Class E

Electrical equipment

Class F

Cooking oil or fat


Fire Fighting Mediums

Type

Old Code

BS EN 3 Colour Code

Fire Class

Water

Signal Red

Signal Red

A

Foam

Cream

Red with a Cream panel above the operating instructions

A

B

sometimes E

Dry Powder

French Blue

Red with a Blue panel above the operating instructions

A

B

sometimes C

E

Carbon Dioxide CO2

Black

Red with a Black panel above the operating instructions

B

E

Wet Chemical

No F Class

Red with a Canary Yellow panel above the operating instructions

A

F

Class D Powder

French Blue

Red with a Blue panel above the operating instructions

D


The element covers quite extensively the need for a site fire plan, correct and adequate signage.

A detailed fire risk assessment should be carried out and firstly any dangerous items or situations should be eliminated, after which strict control measure as previously described should be implemented along with adequate training for personnel. A culture which encourages operatives to report fires by firstly raising the alarm when a possible fire situation is observed without the risk of ridicule should be embraces.

Fire training into the correct procedures to follow in the event of a fire, fire drills, and responsible persons who can verify buy roll call that all people a present.

Records should be kept of fire induction training courses where personnel are informed of procedures, records should also be kept of the testing of equipment

In the event of a fire

  • Raise the alarm
  • Call the Fire Brigade
  • Close all doors and windows to prevent the spread of fire (only if safe to do so)
  • Leave the building
  • Report to assembly point
  • Roll call

If you are properly trained and only if should you

  • fight the fire with the
    extinguishers provided but do
    not put yourself in danger
  • keep between the fire and the
    way out, so that you can get
    out safely

When planning for work the fire risk assessment must be prepared alongside all other documents, thought should be given to the escape routes, any work place must have at least two exits, any controlled fires must be extinguished at the end of work, other hazardous equipment such as gas bottles should have the appropriate valves fitted and turned off when not in use.