NEBOSH IGC-2 Exam Questions & Answers Part-2 (very very useful and simple )

 

 

Element 5: Electrical safety

1. Identify the possible effects of electricity on the body. (page no: 5-2)
§ Electric shock – severe electric shock can cause involuntary muscle grip, heart fibrillation, respiratory failure and cardiac arrest.
§ Burns – burns can also result from an electric shock, at the point of contact and at the point that the current flows out of the body. There may also be internal burns along the current path.
§ Fire and explosion.
§ Arcing.
§ Secondary effects.
2. Outline four factors that may affect the severity of injury from contact with electricity (page no: 5-3) Several factors influence the severity of injury associated with receiving an electric shock:
Voltage – as Ohm’s law shows there is a simple relationship between voltage and current, the higher the voltage, the greater the current.
Duration – the length of time that a person is exposed to the flow of electricity is critical. For example, a current flow of 60 mA for 30 milliseconds (30 thousandths of a second) is unlikely to cause a severe injury, whereas the same current flow over a period of 2 seconds can induce VF and prove fatal.
Frequency – of the AC current.
Current path – the route that the electricity takes as it flows through the body is also critical. If it runs through the chest it is likely to affect the heart.
Resistance – as Ohm’s law shows there is a simple inverse relationship between current and resistance - the higher the resistance the lower the current. Most of the body’s resistance to the passage of electricity is because of the skin. A person with dry skin has a resistance of about 100,000 ohms, but if their skin is wet or damaged this reduces dramatically to 1000 ohms. Any clothing that the person is wearing will also affect their
resistance to the passage of electricity.
Contact surface area – the more skin that is in contact with the live surface, the lower the resistance and the more severe the injury.
Environment – any environmental factors that reduce resistance will cause an increase in current flow and therefore increase the severity of the shock, e.g. wet surfaces, humid air, metal surfaces, etc.

3. In relation to the use of electrical cables and plugs in the workplace identify four examples of faults and bad practices that could contribute to electrical accidents.
• Using unsuitable equipment, e.g. the use of non-intrinsically safe equipment in a flammable atmosphere.
• Using equipment in wet, damp or humid conditions.
• Misuse, e.g. sticking wires directly into a socket rather than using a plug.
• Physical abuse, e.g. pulling the plug out by tugging at the flex; carrying the tool by the flex; allowing the flex to be pinched, trapped or crushed, driving over the flex, etc.
• Repairs carried out by unauthorized personnel or carried out badly, e.g. split flex taped up with insulating tape.
• Continued use of faulty, defective equipment.
• Chemical damage to the flex, e.g. by corrosive wet cement.
• Lack of routine inspection, testing or maintenance.
4. Explain how earthing can reduce the risk of receiving an electric shock. (page no: 5-8)
Earthing is a way of protecting equipment so that in the event of an electrical fault, current flows safely to earth rather than flowing through a person who might be touching the equipment. The earth wire of an item of electrical equipment is usually connected to the outer metal casing or chassis of the equipment. If a fault develops and the casing or chassis becomes live then a current will flow down this earth wire. Electricity always takes the path of least resistance, and since the earth wire will have very low resistance the majority of fault current will flow safely to earth through the wire. Any person touching the casing will receive a minor shock
5. Outline the emergency actions to take if a person suffers a severe electric shock.
The action of discovering a person having suffered an electric shock should be to make others aware of the situation and, at the same time or immediately afterwards, to turn off the supply. If this is not possible, and the victim is still in contact with, or in close proximity to, the live part, then he/she should be pushed clear using a non-conductive implement (such as a broom). First-aid should then be administered, which, depending on the condition of the person, may include cardio-pulmonary resuscitation. If successful, an airway should be maintained by placing the victim in the recovery position and breathing should be monitored until medical help arrives.
6. Outline the practical measures to reduce the risk of injury from electricity when using a portable electrical appliance on a construction site. (page no: 5-5)
§ Consider the use of battery-powered equipment.
§ Consider the use of reduced and low voltage (110v) equipment centre tapped to earth.
§ Provide increased protection through the use of an RCD.
§ Locate cables carefully, away from hazards, e.g. vehicles which may drive over them.
§ Consider the use of double insulated equipment.
§ Carry out pre-use checks of the equipment for signs of damage.
§ Train operators in safe use of the equipment.
§ Avoid using in wet conditions (unless the equipment and supply cables are suitable for this).
§ Implement a programme of routine visual inspection and thorough testing of electrical equipment and cables.
7. In relation to electrical safety, explain the meaning of the following terms:
(i) ‘isolation’ (2)
it refers to shutting of the electrical supply to an item of equipment or part of an item of equipment or part of an electrical system and preventing inadvertent reconnection in order, for instance, to carry out maintenance work.
(ii) ‘earthing’ (2)
this means whereby electrical equipment and conductive items are connected to earth by a cable or metal pope work such that the route to earth provides the path of least resistance to a current flowing under fault conditions.
(iii) ‘reduced low voltage ‘ (2)
Commonly used on construction sites, involves the reduction of local supply voltage by a transformer to a lower, safer voltage – typically 110 or 55volts.
(iv) ‘overcurrent protection’. (2)
A method of preventing the flow of excess current by cutting the supply under fault conditions by means of a fuse or circuit breaker.
8. Identify the electrical hazards that could be discovered by a visual inspection. (8)
· Worn cable
· Max current capacity exceeded

· Overheating
· Defective Equipment
· Exposed electric cable
· Misuse of electrical equipment
· Failure to follow safety instruction
· Incorrect fuse rating
· Poor connections
· Bad circuit connections

Element 6: Fire safety

1. Explain using a suitable sketch, the significance of a ‘fire triangle’.







- Fuel

Any combustible material or substance

- Oxygen

Consumed during combustion when it is chemically combined with the fuel.

- Heat

A heat or ignition source is essential to start the combustion process.
2. Identify four methods of heat transfer and explain how EACH can cause the spread of fire. (In Test book go to page 6-2)

- Conduction:

Where heat is transferred through a conducting material (e.g., metal), without the conductor itself is burning.

- Convection:

As the hot air and gases rise from the fire, cooler air is drawn in which, in turn, his heated and rises. The continuous process of air being drawn in and heated, then rising, cooling and descending, forms circulating currents which enable the fire to spread.

- Radiation:

Heat energy from the fire, in the form of infrared radiation, is transmitted through the air and may be absorbed by other fuel sources causing them to heat up, possibly enough to cause ignition.

- Direct burning:

Combustible materials in direct contact with naked flame.
3. Outline measures that should be taken to minimise the risk of fire from electrical equipment.
(In Test book go to page 6-11)
- Measures such as the proper selection of equipment to ensure its suitability for the task, pre- use inspection by the use, establishing correct fuse ratings, ensuring circuits and sockets are not overloaded, disconnecting or isolating the equipment when it is not in use, and ensuring that electric motors do not overheat (e.g. by checking that vents are uncovered).
- Additional measures include the need to uncoil cables (particularly extension leads) to prevent the buildup of heat and protecting cables from mechanical damage.
- Importantly, electrical equipment and systems should be subject to regular inspection, testing and maintenance by competent persons.
- This should ensure, for instance, that contacts are sound, thereby reducing the likelihood of electrical arcing.
4. List eight ways of reducing the risk of a fire starting in a workplace.(In Test book go to page 6-9)
- Flammable materials are removed from the work area.
- Items that cannot be removed are covered with fire- retardant blankets.
- The floor is swept clean.

- Any wooden floor is damped down.
- A suitable fire extinguisher is at hand.
- A “fire-watcher” is present in the area.
- The work area is visited routinely after the work has finished to check the area for smouldering.
- Ensure that workplace is well ventilated.
- Store and use required minimum volume only.
- Use away from heat and ignition sources.
5. List the five steps in doing an assessment on fire risks. (In Test book go to page 6-5)
- Identify the fire hazards: Sources of fuel, ignition, Oxygen.
- Identify the people who might be harmed (people in the premises and special consideration to vulnerable people).
- Identify and implement the fire precautions that are required,
§ Fire prevention
§ Prevention of the spread of smoke and flames
§ Fire detection and alarm.
§ Means of escape
§ Sign and notice.
§ Lighting.
- Record findings, plan and train
- Review and revise the assessment as necessary.
6. Outline the requirement to ensure the safe evacuation of persons from a building in the event of a fire. (In Test book go to page 6-16)
- The means of raising the alarm
- An acceptable distance to the nearest available exit
- Escape routes of sufficient width
- Clear signing of escape routes
- The provision of emergency lighting
- Escape routes kept clear of obstructions with the fire door closed to prevent the spread of smoke.
- The provision of fire-fighting equipment
- The appointment of fire marshals
- Procedures for the evacuation of those with a physical impairment
- The need to practice the evacuation plant at regular intervals.
7. Outline the general duties of a fire marshal in case of an emergency evacuation in a work place in the event of a fire.(In Test book go to page 6-20)
Fire Marshal might be required to:
- Check all areas in the building to ensure that everyone knows that evacuation is in progress and to help where necessary.
- Give special assistance to the disabled and infirm.
- Fire marshal is responsible for coordinating the fire evacuation plan.
- He should organize fire instruction, training, drills and coordinates the evacuation at the time of the fire.
- He should be made known to workers and they should clearly identifiable at the time of emergency.
- Fire marshal appointment contributes employers’ commitment.
- He is the vocal point to assist authorities.
- By appointing fire marshal, the employer fulfills the legislation requirements.
8. Identify the classification of fires and the associated fuel sources. (In Test book go to page 6-1)
Class A - Solid materials , usually organic, such as paper, wood, coal and textiles.
Class B - Flammable liquids, such as petrol, oil and solvents.
Class C - Gases, such as methane, propane and acetylene.


Class D - Metals such as aluminium or magnesium.
Class K - High temperature fat and oils such cooking fat fire.
9. Identify eight common causes of fires in the workplace. (In Test book go to page 6-3)
- Hot work
- Careless actions and accidents
- Discarded lighted cigarette end or match
- Smoldering waste
- Poor electrical connections
- Overloading electric circuits and using fuse rates too high a rating
- Failure to report and repair faulty equipment promptly
- Defective machinery or equipment
- Deliberate ignition
10) With respect to the design features of a building:
a) Identify TWO types of emergency warning systems that can be installed in the building to help ensure that all workers can be made aware of the need to evacuate the building. (2)
§ Interlinked smoke alarms
§ Automatic fire alarms
§ Smoke detectors
§ Heat detectors
§ Hazard warning lights.
b) Outline SIX structural measures that can help to prevent the spread of fire and smoke. (6)

Compartmentation:

The above scenario is obviously not desirable. If fire prevention does not work and a fire does start in a building, then it should be contained and prevented from spreading. This can be done by designing the building in such a way that it is divided up into separate compartments, each surrounded by fire-resistant materials that can resist the spread of smoke and flame.
This “compartmentation” is done at the initial design and build stage but may also have to be done if a building is changed or modified. This is normally a heavily legislated issue subject to strict control and local standards.

Common Building Materials:

Fire affects different building materials in different ways.
The use of building materials, therefore, has to be tightly controlled to ensure that appropriate materials are used in a structure. For example, fire compartments must be robust enough to withstand the spread of fire for their design time and structural elements in a building should not fail quickly when they are heated in a fire. There will be local regulation and standards to ensure fire safety.
Concrete – is usually very resistant to fire. Does not collapse catastrophically. May “spall” (throw off small chunks).
Steel – is severely affected by high temperatures. Expansion may occur, pushing structural elements apart. Steel may also twist and warp. Can lead to catastrophic building collapse.
Brick – is usually very resistant to fire (bricks are made by exposure to very high temperatures in a kiln).
Timber – thin timber, such as floor boards, will burn, but thick timber, such as structural beams, will not usually burn in a building fire (a layer on the outside of the timber will char and protect the inner core). Thick timber is unlikely to fail suddenly, but will do so slowly.
Insulation (such as wall insulation) can be combustible so fire-retardant versions must be used.

Wall coverings (such as paint and wallpaper) can make a difference to the way fire spreads across surfaces so should also be closely controlled.

Protection of Openings and Voids:

We have already noted that fire doors are used to ensure that door openings are protected in the event of fire. However buildings, and the fire compartments that they are made up of, will inevitably have numerous voids and openings running through them, such as lift shafts, service conduits, air handling ducts, voids between floors, roof voids, etc. and all these need to be protected to ensure that smoke and flame cannot easily travel from one compartment to another.

Element 7: Chemical and Biological health hazards and risk control

1. A factory uses small quantities of various toxic chemicals which re obtained from & returned to a central storeroom.
a) Outline FOUR possible routes of entry of toxic substances into the body & in EACH case, describe a circumstance in which the storeroom staff might be at risk of such exposure.(page no:7-4)
Ingestion – the substance is taken in through the mouth and swallowed down into the stomach and then moves on through the digestive system. This is a less significant route of entry since people are unlikely to deliberately swallow a hazardous substance. Ingestion usually occurs by cross-contamination (of the hands by a toxic substance) or by mistaken ingestion.
Absorption through the skin – the substance passes through the skin and into the tissues beneath and then into the blood stream. Only some substances (e.g. organic solvents) are able to permeate the skin in this way, but when they can this route can be very significant since any skin contact allows absorption. Injection through the skin – the substance passes through the skin barrier either by physical injection (e.g. a needle-stick injury) or through damaged skin (cuts and grazes). This route is significant for many biological agents (e.g. hepatitis).
Inhalation – the substance is breathed in through the nose and mouth and down into the lungs. This is a significant route of entry for many hazardous substances in the gas, vapour, mist, fume or dust form.
People have to breathe; if the hazardous substance is present in the air around them then it will be inhaled. Dust can be inhaled through the nose and mouth in this way, but not all dust will travel down into the lungs. Dust is made up of small particles of various diameters. Large dust particles are filtered out by the lungs’ defence mechanisms before they can travel down into the lungs; smaller particles are not trapped by these defences and will travel deep into the lungs.
b) Identify the factors to consider when assessing the health risk to storeroom staff from handling the chemicals. (page no: 7-7)
§ The hazardous nature of the substance present – is it toxic, corrosive, carcinogenic,etc.?
§ The potential ill-health effects – will the substance cause minor ill-health or very serious disease and will these result from short-term or long-term exposure?
§ The physical forms that the substance takes in the workplace – is it a solid, liquid, vapour, dust, fume, etc.?
§ The routes of entry the substance can take in order to cause harm – is it harmful by inhalation,ingestion, skin absorption, etc.?
§ The quantity of the hazardous substance present in the workplace – including the total quantities stored and the quantities in use or created at any one time.
§ The concentration of the substance – if stored or used neat or diluted, and the concentration in the air if airborne.
§ The number of people potentially exposed and any vulnerable groups or individuals – such as pregnant women or the infirm.
§ The frequency of exposure – will people by exposed once a week, once a day or continuously?
§ The duration of exposure – will exposure be very brief, last for several hours or last all day?
§ The control measures that are already in place - such as ventilation systems and PPE.
c) Identify the control measures that might be required in order to minimize the risk to the health of those working in the store room. (page no:7-14,15)
§ Minimization of emission, release and spread of hazardous substances through design and operation of processes and task activities.
§ Effectiveness and reliability of control options that minimize the escape and spread of hazardous substances.
§ Exposure control to be proportional to health risk.
§ Personal protective equipment (PPE).
§ Other PPE and clothing
§ Personal hygiene and protection regimes.

§ Health and medical surveillance
2. Identify possible routes of entry of biological organism into the body.
§ Mother to child
§ Interchanging of body fluids
§ Ingestion
§ Injection
§ Inhalation
§ Absorption
3. Outline control measure that could be used to reduce the risk of infection from biological organisms. (page no:7-23)
Sterilization and disinfection – this process removes the biological agent and therefore the hazard. It is often used to treat wastes to make them safe for disposal, e.g. treatment of used laboratory equipment, contaminated medical supplies, etc. Disinfection of workrooms and benches is an important control to minimise the spread of infectious materials.
PPE can be used to prevent contamination of clothing (e.g. lab coats), or to prevent materials entering the body (e.g. respiratory and eye protection to prevent entry via inhalation or absorption, gloves to prevent contact with broken skin). Those handling biological agents should ensure that open wounds are covered at all times.
The use of microbiological agents can often be restricted to a designated area, e.g. the use of microbiological safety cabinets (similar to laboratory fume hoods in principle but filtered to prevent the escape of agents) is common place; however if the agent is on a host, such as an animal, then quarantine areas may be needed.
Spill containment methods which prevent release of agents are required. Spill trays may be used in laboratories, whilst uncontrolled releases of, for example, body fluids such as blood may be treated with a chemical to contain and disinfect.
High standards of personal hygiene are essential – smoking, drinking, eating and applying cosmetics should all be banned in the workplace, and clothing should be changed (e.g. lab coats removed) before entering uncontaminated areas.
Finally vaccinations may be used to prevent infection in some instances, e.g. the hepatitis B vaccinations for first aiders already mentioned.
4. A worker is engaged in general cleaning a large veterinary Clinic.
a) Identify FOUR specific types of hazard that the cleaner might face when undertaking the cleaning.

Ans: FOUR specific types of hazards can be:

· Cleaning workers are at risk of exposure to zoonoses, infectious diseases that spread from animals to humans. Possible routes of transmission include aerosol, droplet spray, ingestion (oral), direct contact, indirect contact. Sources of exposure include animals, body fluids, contaminated tools, surfaces, or other objects in the environment.
· Cleaning workers are exposed to additional biological hazards especially from the animal droppings which may contain a contagious disease.
· Different chemical hazards including glutaraldehyde and other disinfectants, hazardous drugs, latex , pesticides, and waste anesthetic gases exist in the veterinary clinic. Exposure to these chemicals may occur by dermal contact and/or inhalation (being breathed in)
· Workers may be exposed to blood borne pathogens while cleaning the blood of animals
· Additional hazards may include slip while cleaning the biological and /or chemical spills
b) Outline the precautions that could be taken to minimize the risk of harm from these hazards

Ans: Following precautions can be adopted at a workplace:

· Personal hygiene practices are the best way to protect the workers from exposed hazards
· Hand washing routines and use of hand sanitizers to be made part of workers daily job routines
· Double bag all the chemical waste, partially filled vials, undispensed products, needles and syringes, gloves, gowns, mats and contaminated materials from spill clean ups and animal bodily fluids
· Prohibition of eating, drinking and smoking in the workplace
· Health Surveillance of the workers to be carried out for health monitoring and biological monitoring
· Sterilisation to be carried out to treat wastes to make them safe for disposal
· Disinfection to be carried out immediately for the work room and benches to minimize the spread of infectious materials
· Vaccinations may be used for the workers in some instances e.g. hepatitis B

· Post the sign to warn employees that they are working in an environment where hazardous drugs are being handled
· Train workers to recognize and understand the risks of working with hazardous chemicals used as drugs and the biological hazards they are going to face while cleaning
· Training for the use of spill kits followed by the mock drills for the spills at workplace to make workers trained how to deal with the spill
· Cleaning workers should be part of the dedicated team who carry out the spillage control at the workplace
· Use of proper personal protective equipment which include but not limited to specialized gloves, safety shoes (only for cleaning not to be worn outside), coveralls, safety goggles, hair nets etc.
5. A company produces a range of solid and liquid wastes, both hazardous and non-hazardous. Identify the arrangements that should be in place to ensure the safe storage of the wastes prior to their collection and disposal. (page no:7-29)
• The hazardous nature of the waste – the waste may be inherently hazardous to staff involved in handling it, e.g. toxic or radioactive. This may require the use of PPE.
• The waste may present a manual handling risk.This might be overcome by the use of mechanical handling equipment or handling aids.
• Storage equipment such as skips, bins and compactors may be difficult to access and may require steps or platforms to allow safe use.
• Waste containers/skips should be stored on concrete surfaces and not on unstable or unmade ground (grass or earth) to prevent contamination of ground and groundwater.
• Compactors will have moving parts that must be effectively guarded to prevent access.
• Collection vehicles such as skip lorries present a significant hazard when manoeuvring, especially when reversing (use a banksman).
• The waste may present a temptation to scavengers (e.g. waste metals) and to vandals (unlocked storage tank valves) and so must be secured.
• Stored liquid waste should be contained in either a double-skinned container or the vessel should be contained in a bund.
• Containers should be located away from bund walls.
• Bunds should have the capacity to store 110% of the volume of the largest container in the bund.
• Provision should be made to empty the bund of rainwater if the storage area is outside (or a roof installed to prevent rainwater ingress).
• Where liquids are pumped, transferred or decanted the transfer points or tanker connections should also be contained in a bunded area or the operation carried out over a drip tray.
• Bunds may need to be protected from damage, e.g. by vehicles such as tankers approaching to make deliveries.
• Bunds will need to be checked and maintained to ensure that they do not leak.
• Any escape may have the potential to cause pollution. Adequately securing the waste might control this risk, but emergency spill or release plans may also be required, along with the necessary personnel, equipment and training to put these plans into effect (see Topic Focus).
• Waste types (streams) must be segregated to prevent the mixing and contamination of one type of waste with another. This usually requires separate secure storage for each type of waste and the clear identification of types.
• Appropriate documentation should accompany the waste and the duty of care, to dispose of waste in line with legal requirements, must be fulfilled.
6. Outline the precautions to ensure the health & safety of persons engaged in spray painting activities in a motor vehicle repair shop.
· As proper ventilation is important when working with paint coatings, a spray booth is an excellent way to remove spray paint vapors and debris from a worker’s breathing zone
· To provide maximum protection, the spray booth must be properly maintained, including regular cleaning of filters and overspray
· When painting in an enclosed space (a room),provide outside ventilation air with fans or open windows & turn off ignition sources like wall heaters
· The air-purifying type of respirator should be used only during exposure to those specific chemicals, or groups of chemicals, described on the respirator cartridge. While the atmosphere-supplying type of respirator must be used in some paint spraying operations, particularly with urethane paints or

when painting in a confined space e.g. inside a tank. Other PPE to be used can be eye googles and coveralls.
· Some of the chemicals you work with can injure skin or cause dermatitis. Coveralls and gloves prevent these chemicals from coming into contact with your skin, reducing the risk of damage. Wear your coveralls and gloves whenever working with chemicals. Clean your gloves and wash your coveralls regularly to prevent chemicals from accumulating, especially around the cuffs where they can easily come into contact with your skin. As an additional protective measure, use BARRIER CREAMS on your hands, face and neck. Check to make use you have the correct barrier cream for the chemicals being used.
· Because of the danger of fire and explosion where paints which contain flammable solvents are being used, care should be taken to remove all potential sources of ignition before starting work. This means naked flames, cutting and welding torches, gas fired heaters and materials which may give off sparks, whether electrical, mechanical, friction or static, and there must be no smoking. Make sure the correct types of fire extinguishers are available at the work site
· Many painting projects require preparation of the materials to be painted. Preparation often involves sanding of the surface which creates a health hazard if dust masks are not worn. Ideally dust collection systems should be used to prevent large amounts of small particulates from entering the air. Sanding and scraping of old paint may hold additional hazards if the old paint contains lead.
· Understand the information given with the material safety data sheet of the paint been used. For most people who work with a material, there are sections of the MSDS that are more important than others. You should always read the name of the material, know the hazards, understand the safe handling and storage requirements, and understand what to do in an emergency.
· Hazard Communication Standard (HAZCOM) needs to be implemented at the work place. The Hazard Communication standard requires employers to; maintain an inventory of hazardous materials, provide employees training on the potential hazards associated with a material, obtain and maintain MSDSs for each material onsite, establish proper methods and types of labels, and inform contractors of the hazards that their employees may be exposed to in their work area
· Step ladders are commonly used for painting. Ladder safety begins with selecting the right ladder for the job and includes inspection, setup, proper climbing or standing, proper use, care, and storage. This combination of safe equipment and its safe use can eliminate most ladder accidents
· One of the most common health hazards associated with exposure to solvents is dermatitis. This can be avoided by use of substitute solvents which are less hazardous to health
· Use of safety signage with no smoking, no welding to be posted
· Grounding of all spraying equipment
7. Identify the sources of information which could be used in the assessment of risk to toxic substances. (page no:7-7)
• The hazardous nature of the substance present – is it toxic, corrosive, carcinogenic,etc.?
• The potential ill-health effects – will the substance cause minor ill-health or very serious disease and will these result from short-term or long-term exposure?
• The physical forms that the substance takes in the workplace – is it a solid, liquid, vapour,dust, fume, etc.?
• The routes of entry the substance can take in order to cause harm – is it harmful by inhalation, ingestion, skin absorption, etc.?
• The quantity of the hazardous substance present in the workplace – including the total quantities stored and the quantities in use or created at any one time.
• The concentration of the substance – if stored or used neat or diluted, and the concentration in the air if airborne.
• The number of people potentially exposed and any vulnerable groups or individuals – such as pregnant women or the infirm.
• The frequency of exposure – will people by exposed once a week, once a day or continuously?
• The duration of exposure – will exposure be very brief, last for several hours or last all day?
• The control measures that are already in place - such as ventilation systems and PPE.
8. Identify the sources of information available in Material Safety Data Sheet. (page no:7-8)
§ Identification of the substance or preparation and supplier – including name, address and emergency contact phone numbers.
§ Composition and information on ingredients – chemical names.
§ Hazard identification – a summary of the most important features, including adverse health effects and symptoms.

§ First aid measures – separated for the various risks, and specific, practical and easily understood.
§ Fire-fighting measures – emphasizing any special requirements.
§ Accidental release measures – covering safety, environmental protection and clean-up.
§ Handling and storage – recommendations for best practice, including any special storage conditions or incompatible materials.
§ Exposure controls and personal protection – any specific recommendations, such as particular ventilation systems and PPE.
§ Physical and chemical properties – physical, stability and solubility properties.
§ Stability and reactivity – conditions and materials to avoid.
§ Toxicological information – acute and chronic effects, routes of exposure and symptoms.
§ Ecological information – environmental effects, which could include effects on aquatic organisms, etc.
§ Disposal considerations – advice on specific dangers and legislation.
§ Transport information – special precautions.
§ Regulatory information – overall classification of the product and any specific legislation that may be applicable.
§ Other information – any additional relevant information (e.g. explanation of abbreviations used).
9. Explain the difference between acute and chronic health effects. (4)
Acute Effect: Is an immediate or rapidly produced, adverse effect, following single or short term exposure to an offending agent which is usually reversible.
Chronic Effect: Is an adverse health effect produced as a result of prolonged or repeated exposure with a gradual or latent, and often irreversible, effect that may often go unrecognized for a number of years.
10. Identify the factors affecting the suitability of Respiratory Protective Equipment. (page no: 7-20)
§ Concentration of the contaminant and its hazardous nature.
§ Physical form of the substance, e.g. dust or vapor.
§ Level of protection offered by the RPE.
§ Presence or absence of normal oxygen concentrations.
§ Duration of time that it must be worn.
§ Compatibility with other items of PPE that must be worn.
§ Shape of the user’s face and influence on fit.
§ Facial hair that might interfere with an effective seal.
§ Physical requirements of the job such as the need to move freely.
§ Physical fitness of the wearer.
11. Identify factors that could reduce the effectiveness of Local Exhaust Ventilation. (page no: 7-16)
§ Poorly positioned intake hoods.
§ Damaged ducts.
§ Excessive amounts of contamination.
§ Ineffective fan due to low speed or lack of maintenance.
§ Blocked filters.
§ Build up of contaminant in the ducts.
§ Sharp bends in ducts.
§ Unauthorised additions to the system.
12. Outline two types of cellular defence mechanisms that the body has as a natural defence system. (page no: 7-12)

Respiratory Defences

The respiratory system is made up of the nose and nasal cavity, windpipe (trachea) and lungs. The air passes down the bronchi and bronchioles to the alveoli. These are small air sacs and are the area where oxygen enters the bloodstream.
The respiratory system is protected by the following defences:
The sneeze reflex:Filtration in the nasal cavity (which has a thick mucus lining that particles stick to). This is very effective at removing large particles; only particles less than 10 microns in diameter pass through.
Ciliary escalator – the bronchioles, bronchi and trachea are lined with small hairs (cilia). Mucus lining these passages is gradually moved by these cilia up out of the lungs. Any particles trapped in this mucus are cleaned out of the lungs by this mechanism. This filtration mechanism is effective at removing all particles larger than 7 microns in diameter.
Macrophages – scavenging white blood cells that attack and destroy particles that lodge in the alveoli (where there are no cilia to extract them).


Skin Defences

The skin forms a waterproof barrier between the body and the outside world. It is made of two layers, the outer epidermis and the inner, thicker dermis. Defence mechanisms include:
• A thick layer of dead cells at the surface of the epidermis that are constantly being replenished as they wear off.
• Sebum – an oily fluid secreted onto the surface of the skin that has biocidal properties.
13. Give the meaning of the term ‘Maximum allowable concentration’. (In Test book go to page 7-13)
The maximum exposure to a biologically active physical or chemical agent that is allowed during an 8-hour period (a workday) in a population of workers, or during a 24-hour period in the general population, which does not appear to cause appreciable harm, whether immediate or delayed for any period, in the target population. (OR) Exposure concentration not to be exceeded under any circumstances.
14.(a) Explain the health risks associated with exposure to the leptospira bacteria. (page no:7-26)
The disease leptospirosis starts with flu-like symptoms (fever, headache, and muscle pain) and then progresses to a more serious phase involving jaundice. At this stage the disease is causing liver damage and may be known as Weil’s disease. If diagnosed early the disease is usually treated successfully. It can prove fatal, especially if diagnosed late.
(b) Identify the workplace circumstances where leptospira bacteria may be present. (page no:7-26)
§ Leptospira bacteria commonly infect animals such as rats,mice, cattle and horses.
§ Infected rats pass the bacteria in their urine, perhaps onto wet surfaces or into water where the bacteria can stay alive.
§ If contaminated water comes into contact with cuts or grazes, or is ingested, then infection may occur.
§ Occupations at risk are those who work with potentially infected animals (e.g. dairy farmers) or in wet areas where there may be rats (e.g. sewer workers, water sports instructors)
(c) Identify precautions that will reduce the risks from exposure to leptospira bacteria. (page no:7-26)
§ Preventing rat infestation, by good housekeeping and pest control.
§ Good personal hygiene (e.g. hand-washing).
§ PPE (especially gloves).
§ Covering cuts and grazes.
§ Issuing workers with an “at risk” card to be shown to the worker’s doctor (physician) to allow early diagnosis.
16. A dust produced during a work process contains a substance that is classified as toxic and has been assigned a workplace exposure limit.
a) Give the meaning of the term ‘Toxic’. (page no:7-2) (2)
Toxic – small doses cause death or serious illhealth when inhaled, swallowed or absorbed via the skin (e.g. potassium cyanide (KCN)).
b) Give the meaning of the term ‘Workplace Exposure Limit’. (page no:7-12) (2)
Maximum concentrations of airborne contaminants, normally measured across particular reference period of time, to which employees may be exposed.
c) Identify the Limitations of WEL. (6)
· Whenever exposure to the hazardous substances is such that an identifiable disease or adverse health effect may be linked to the exposure
· Whenever there is an increase in registration of occupational illness and health cases at a work place with a probability that the work is affecting the health of employees
· After there is a change in the work activities and these activities pose additional hazards to health of employees working in the hazardous environment
· Whenever the Local Exhaust Ventilation Systems installed is working effectively
· After a major accident which has caused the employees to be exposed to hazardous environment above the permissible limit
· After the independent third party carrying out health surveillance at the workplace and shows that the exposure limits are above maximum allowable concentrations
17) Asbestos is to be removed from a building used as a workplace.
a) Outline the difference between acute AND Chronic health effects (4)

Acute Effect: an irreversible and immediate or rapidly produced adverse effect, when exposed to single or short term exposure.
Chronic Effect: An exposure which is usually prolonged and repeated which can lead to various health effects like Noise Induced hearing loss is known as chronic effect.
b) Identify the possible chronic health risks from exposure to asbestos. (page no:7-24) (2)
§ Asbestosis
§ Lung cancer
§ Mesothelomia
c) Outline where asbestos may be found within the building (page no: 7-24) (4)
§ Roofs (asbestos cement)
§ Ceilings (ceiling tiles)
§ Floors (floor tiles)
§ Pipes (downpipes)
§ Decorative plasters (artex)
§ Insulation (pipe lagging)
d) Outline control measures that should be considered before and during the
removal of asbestos. (page no: 7-24) (10)
§ Provide Personnel protective equipment and respiratory protective equipment.
§ Information to given to appropriate legal and other interested agencies.
§ Ensure adequate supervision is maintained at all times.
§ Contaminated air needs to be collected without allowing it to escape to outer air.
§ Monitoring of work exposure limit as per standard.
§ Ensure appropriate Local Exhaust Ventillation is provided throughout the job.
§ Regular monitoring of air quality to be done.
§ Only competent and trained personnel to do the job.
§ All workers are subjected to health surveillance at regular intervals and recorded.
§ Accumulated wastes are to be collected only in the designated waste bags with correct identification.

Element 8: Physical and Psychological health hazards and risk control

1. Explain the following terms in relation to noise exposure at work.
a) Noise-induced hearing loss.
b) Tinnitus
(In Test book go to page 8-1)
a) Noise-induced hearing loss
- Noise induced hearing loss is normally caused by prolonged exposure to high noise levels causing damage to the hair cells and leading to a permanent threshold shift at particular frequencies, which worsens with continued exposure both in terms of the extent of the threshold shift and of the frequencies affected.
b) Tinnitus
- Tinnitus on the other hand is typified by a ringing or similar sound in the ears caused by over- stimulation of the hair cells. It can be acute or chronic, permanent or intermittent.
2. Identify four limitations of personnel hearing protection as a means of protecting against the effects of noise or identify the factors that are likely to affect the performance of personnel hearing protection.
(In Test book go to page 8-4)
Ear Muffs
- Uncomfortable when worn for long time.
- Must be routinely inspected, cleaned and maintained.
- Efficiency may be by long hair, spectacles or earrings.
- Incompatible with some other items worn (e.g. spectacles)

- Needs dedicated storage facility. Ear Plug
- Difficult to see when fitted, so supervision and enforcement difficult.
- Risk of infection if dirty or if cross-contaminated when inserted.
- Interface with communication.
- Effectiveness decreases with usage.
- Need to be correctly sized to fit the individual.
3. Outline four types of engineering control that may be used to reduce noise in the workplace giving an example of each.
(In Test book go to page 8-4)
- Source:
Eliminating or reducing noise at the design stage e.g. nylon bearings instead of metal.
- Substitute the source:
Change the noise source for something else that does the same job but generates less noise (e.g. change a petrol-driven machine for an electric version).
- Silencing:
An attachment is fitted to the exhaust of a machine the baffles reduce the noise.
- Damping:
Reduction in structure born noise by use of rubber/cork, springs etc in noise path e.g. panels, motors etc or by reducing vibration.
- Isolation:
Protection of persons from noise source by distance or sound proofed rooms.
- Lagging:
On pipes carrying steam or hot mud’s insulation of pipes to reduce sound transmission.
- Absorption:
Absorbing sound in the work area by means of acoustic absorbent panels on walls or ceilings
- Enclosure:
Placing a sound-proof cover over the noise source.
4. In relation to ill-health effects from the use of vibrating hand held tools identify the typical symptoms that might be shown by affected individuals.
(In Test book go to page 8-7)
- Hand-Arm Vibrating syndrome (HAVS)
- Vibration White Finger (VWF)
- Nerve Damage
- Muscle weakening
- Joint damage
5. Outline the control measures that may be used to minimize the risk of health effects caused by using the vibrating hand held tools.
(In Test book go to page 8-8)
- Reduce the vibration at source.
- Substitute the source.
- Changing work techniques.
- Periodical Maintenance
- Interrupt the pathway from source to receiver.
- Isolation of vibrating parts.
- Limit the duration of exposure.
- Job rotation
6. For each of the following types of non-ionizing radiation, identify a source and state the possible ill-health effects on exposed individuals.
a) Infrared Radiation.
b) Ultraviolet Radiation (In Test book go to page 8-12)

a) Infrared Radiation
- Red hot steel in a rolling mill, Fire or furnaces and glass manufacture.
b) Ultraviolet Radiation
- welding operations, Sun.
8. Identify the general methods for protecting people against exposure to non-ionizing radiation. (In Test book go to page 8-13)
- Shielding
- Increasing the distance between source and person
- Reducing the duration of exposure
- Appropriate personal protective equipment
- The use of barrier cream.
- By following Safe system work / permit to work system.
- Change the competent person often to reduce the impact.
9. Outline the factors that may lead to unacceptable levels of occupational stress amongst worker. (In Test book go to page 8-15)
- Excessive demands of the job in terms of workload, speed of work and deadlines
- Frequent changes in the working pattern (e.g. changing shift patterns)
- Exposure to noise & vibration
- Extremes of temperature and or humidity
- Cramped conditions
- Dirty or untidy working conditions
- Workplace layout resulting in a lack of privacy or security
- Poor lighting
- Problems with glare
- Inadequate ventilation resulting in stale air
- Inadequate welfare facilities
- Those working outside, inclement weather conditions