OTHM Unit 5.pptx

UNIT 5 Maintaining a safe work environment  Learning outcomes Assess a range of factors to consider for safe working environment Assess the hazards, risk and controls applicable to the hazard of Electricity Analyze the hazards, risk and controls applicable to structural integrity Analyze the hazards, risk and controls applicable to Work at height, Confined Space & Lone working Analyze the hazards, risk and controls applicable to Mobile working equipment or vehicles at site Assess the hazards, risk and controls applicable to Noise, Vibration & Radiation Analyze the maintenance of fire safety and protection against explosion Analyze safe storage, handling and management of hazardous substances, including biological agents. Analyze hazards, risk and controls of Work equipment and machinery Welfare Provision ILO C120 - Hygiene (Commerce and Offices), Convention, 1964 (No. 120) ILO C167 - Safety and Health in Construction Convention, 1988 (No. 167) • Drinking water. • Sanitary conveniences. • Washing facilities. • Changing rooms. • Accommodation for clothing. • Rest and eating facilities. Group Exercise What basic welfare facilities would you expect an employer to provide for the following groups of people? • Accident and emergency nurse. • Construction worker. • Office-based accountant. Welfare Provision Minimum standards: Drinking water • Wholesome, labelled if not. Sanitary conveniences • • • • • Washing facilities • • • • Sufficient numbers. Separate for men and women. Protected from weather. Clean, lit and ventilated. Provision for the disabled. Close to toilets and changing rooms. Showers if required. Hot and cold water, soap, towels. Means of drying. Welfare Provision Minimum Changing rooms standards: • For special workwear. • Lit, cleaned and ventilated. • Separate facilities for men and women. Accommodation for clothing • Lockers, etc. • Personal clothing clean and secure. • Separate storage for dirty workwear. Rest and eating facilities • • • • • Sufficient seats and tables. Away from work location. Hygienic environment. Means of preparing hot food and drink. Separate facilities for new and expectant mothers. Work Environment Requirements Minimum standards: Space Seating Ventilation Heating Lighting • Adequate space to allow workers to perform task safely. • Appropriate seating. • Stable, backrest and footrest where appropriate. • Sufficient supply of fresh or purified air. • Reasonable temperature indoors: ○ Sedentary work 16oC (inactive or seated). ○ Manual work 13oC. • Adequate lighting. Work Environment Requirements • Minimum levels achieved (measured in ‘lux’). • Natural light is best. • Lighting adjusted to the level of detail required. • Local lighting may be necessary. • Local lighting on critical areas. • No reflections or glare. • No creation of shadows. • No flickering. • Suitable for the environment. • Emergency lighting should be provided if mains power fails. Group Exercise What are the health issues associated with working in: • Hot environments? • Cold environments? How can these health risks be controlled? Effects of Exposure Hot environments: Cold environments: • Dehydration. • Hypothermia. • Muscle cramps. • Frostbite. • Heat stress. • Heat exhaustion. • Slip injuries (on icy floors). • Heatstroke. • Freeze burn injuries. • Burns/skin damage. Preventive Measures Hot environments: Cold environments: • Ventilation. • Prevent or protect from draughts. • Insulate/shield heat sources. • Provide cool refuges. • Drinking water. • Frequent breaks. • Job rotation. • Appropriate clothing. • Shield/lag cold surfaces. • PPE – insulating. • Provide warm refuges. • Frequent breaks. • Job rotation. • Access to warm food Introduction to Electricity An electrical circuit has three parameters: Voltage (V) or potential difference: • Measured in volts. Current (I) or rate of flow: • Measured in amps. Resistance (R) to the flow: • Measured in ohms. Linked together by Ohm’s Law: V=I×R Introduction to Electricity Alternating Current (AC): Direct Current (DC): • Mains supply is AC. • Battery supply is DC. • Voltage alternates from +ve to -ve and back again. • Therefore current flows backwards and forwards. • UK = 230 volts, 50 Hz. • US = 120 volts, 60 • Current flows in one direction only. The Hazards and Risks of Electricity • Electric shock. • Burns. • Fires and explosion. • Arcing. • Secondary effects. Electric Shock Current (mA) flowing through the body Effect 0.5–2 Threshold of sensation 2–10 Tingling sensations, muscle tremor, painful sensations 10–60 Muscle contractions, inability to let go, inability to breathe 60 and above Ventricular fibrillation, cardiac arrest, extreme muscle contractions, burns at contact points and deep tissues Electric Shock The severity of shock is influenced by: Voltage Higher the voltage, greater the current Duration Current path Resistance Contact surface area Exposure time Environmental factors Clothing and footwear Frequency Metal surfaces, humidity, etc. Route through the body Skin condition, clothing, etc. More skin contact, more severe injury Affects resistance and blocks/reduces current flow AC more harmful than DC at same shock current Electrical Burns Direct electrical burns: • Current flowing through the body. • Entry and exit point. • Internal tissue burns. Indirect electrical burns: • An electrical accident causing something to overheat or explode, e.g. arc flash. Electrical Fires and Explosions Causes: Faulty electrical equipment overheating. Overloaded system. Overheating during charging. Equipment may be misused. Flammable atmosphere: ‒ With wrong type of equipment. ‒ Accidentally created. • Electrical equipment producing heat or sparks in normal use. • Poor internal electrical connections. • • • • • Static Electricity • Build up of potential difference (volts) between surfaces. • Caused by friction. • Surfaces become ‘charged’. • Static shock. • Very short-duration static spark. • Spark caused on contact with earth. • Risk of igniting flammable liquids, etc. Arcing Ability of electricity to ‘jump’ across an air gap: • Usually involves high voltage, e.g. overhead power lines. Main hazards: • • • • Electric shock. Direct burns from the arc. Indirect burns from the radiant heat. Damage to eyes from UV light. Secondary Effects Physical injury caused by an electrical incident, e.g. falling off a ladder causing: • Cuts. • Bruises. • Broken bones. Fixed and Portable Electrical Equipment Conditions and practices likely to lead to accidents: • Unsuitable equipment. • Using equipment in damp conditions. • Misuse. • Physical abuse. • Improper repairs, e.g. taped-up joints. • Use of faulty, defective equipment. • Chemical/abrasion damage to the flex. • Lack of inspection, testing or maintenance. Protection of Conductors • Insulated to prevent contact with live conductor: ‒ Cable coverings unbroken. ‒ Equipment casing intact. • Inspect to ensure protection is in place. • Ensure electrical panels are locked. Strength and Capability of Equipment Electrical equipment must be carefully selected to ensure that it is suitable for the: • electrical system that it will become a part of; • task that it will perform; and • environment in which it will be used. No electrical equipment should be put into use where its electrical strength and capability may be exceeded. Strength and Capability of Equipment Consider: •Weather. •Natural hazards, e.g. gnawing by rats. •Extremes of temperature and pressure, e.g. heat from motors. •Dirty conditions. •Corrosive conditions. •Liquids and vapours, e.g. splashing. •Flammable substances. •Foreseeable mechanical damage. Protective Systems and Devices • Fuses and miniature circuit breakers. • Earthing. • Isolation of supply. • Double insulation. • Residual Current Devices (RCDs). • Reduced and low-voltage systems. Fuses and Miniature Circuit Breakers Fuses: • Prevents current overload: ‒ An overcurrent protection device. • Weak link in a circuit. • Overheats and melts if the current exceeds the fuse rating. • Designed to protect equipment, not people. • Advantages? • Disadvantages? Fuses and Miniature Circuit Breakers Miniature circuit breakers: • Similar to a fuse. • Prevents current overload: ‒ An overcurrent protection device. • Electromechanical device. • Trips a switch. • Can be reset. • Tamper-proof. • Designed to protect equipment, not people. • Advantages? • Disadvantages? Earthing • In event of a fault, provides a safe path to earth. • Outer metal casing connected to earth by wire. • Electric shock should be minor. • Advantages? • Disadvantages? Isolation of Supply • Removal of electrical power from a circuit or system. • Switch/isolator or removing the plug. • Circuit ‘dead’ and safe to work on. • Physically secured by lock (lock-out/tag-out). • Should be clearly labelled. • Circuit should be tested. • Advantages? • Disadvantages? Double Insulation • Live parts or parts that might become live under fault conditions cannot be easily touched. • Often achieved by having two layers of insulation between live conductors and any external metal surfaces or external surfaces are non-conducting (plastic). • Called Class II equipment. • No need for earth protection. • Advantages? • Disadvantages? Residual Current Devices • Specifically designed to protect human life. • Constantly compares current in live and neutral. • Sensitive to small current imbalance, i.e. leak to earth: ‒ Very sensitive: 30 mA. ‒ Very fast: 40ms. • Can be used: ‒ As part of a plug. ‒ As standalone device. ‒ Hard-wired into distribution system. • Advantages? • Disadvantages? Reduced and Low-Voltage Systems As voltage is reduced, so the shock current is reduced: • UK voltage 230 V stepped down to 110 V for portable tools. • 50 volts equipment (SELV). Reduced and Low-Voltage Systems Control measures when selecting portable electrical equipment on construction sites: • Use battery-powered, reduced- or low-voltage equipment. • Use RCDs. • Locate cables carefully. • Use double-insulated equipment. • Carry out pre-use checks. • Train operators in correct use. • Avoid using in wet conditions. • Implement routine visual inspection and testing. Competent Persons • Knowledge of electricity. • Experience of electrical work. • Understanding of the system. • Understanding of hazards and precautions. • Ability to recognise whether safe to continue work. Use of Safe Systems of Work • Work ‘dead’ whenever possible. • Work on or near live electrical equipment: ‒ ‒ Only under exceptional circumstances. And if controlled tightly. Working on or Near Live Electrical Systems No live working unless no alternative. If essential, safe system of work to include: • Permit to work. • Competent persons. • Insulating PPE such as boots and gauntlets. • Insulated tools and equipment. • Designated work areas. Isolation Usually requires: • The breaking of the circuit. • Physical securing of the break in the circuit. • Some form of label (or tag). Emergency Procedures Following an Electrical Incident • Don’t touch the casualty. • Call for help and ambulance. • Turn off power supply. • If can’t switch off power, isolate casualty from the supply. • Check for breathing: ‒ Recovery position if breathing. ‒ Start CPR if not breathing. • Treat burns. • Treat for physiological shock. • Ensure medical help is obtained. Inspection and Maintenance Strategies • Applies to: ‒ Fixed wiring systems. ‒ Portable appliance testing. • Combined inspection and testing. User Checks • Body of plug intact and secure. • Outer flex sheath covers all inner wires. • Plug and appliance cable clamp tight. • Flex fully insulated - no splits or kinks. • Body of appliance intact. • No damage to casing of equipment. • No burns/scorch marks. • Not soiled or wet. Formal Visual Inspection User checks plus: • Remove plug cover and check: ‒ Fuse. ‒ Connections are secure. ‒ Terminals are secure. ‒ No signs of internal damage. • Competent person. Combined Inspection and Testing Visual inspection may fail to detect: • Deterioration of insulation. • Defective earth pathway. Inspection and test: • When suspect equipment is defective. • After repair/modification. • At appropriate intervals. • Competent person. What is Structural Integrity? “Structural integrity is an engineering field that helps ensure that either a structure or structural component is fit for purpose under normal operational conditions and is safe even should conditions exceed that of the original design. This includes supporting its own weight, aiming to prevent deformation, breaking and catastrophic failure throughout its predicted lifetime.” Causes of Structural Failure? Structural failure can occur from a range of different sources. The type of failure is often associated with the industry, environment and application of the structure. The primary reasons for failure are as follows: •Weak structures. The structure is not strong enough to withstand the load to which it is subject. This is usually due to inappropriate geometric design or material choice •Structural deterioration. The structure deteriorates due to corrosion, fatigue, wear, rot or creep. Fatigue failures often begin when cracks form at regions of high stress. These cracks grow when subject to cyclic loading, resulting in sudden failure. This is usually due to inappropriate geometric design, material choice or maintenance •Manufacturing errors. This includes using the wrong materials or not following manufacturing procedures or standards. It can also result from poor workmanship or components being out of tolerance, etc. •Defective material. The materials don't conform to standards, resulting in a lower load bearing capacity than designed. •Improper environmental considerations. Engineers may neglect mitigating features for certain environmental conditions, such as natural disasters •Improper operational conditions. The structure is not Temperature and Structural Integrity Structural steels are used in most large construction projects, such as buildings and bridges, in the form of girders etc. The performance of the steel is vital to maintain the required integrity. High temperatures are known to weaken steel, which begins to soften at around 425°C and loses about half of its strength at 650°C. At these temperatures, the steel will begin to buckle and twist if subject to high loads, which will impede structural integrity. Consequently, engineers must take into account the environmental temperature range that a structure will be subject to over its life span Calculate the Integrity of Structures Engineers combine an array of considerations into the design process, such as materials performance, stress analysis and fracture mechanics. Once built, a construction will need inspection and maintenance to maintain its integrity. To do this, an engineer might: • Carry out inspections to identify damage. This might involve the use of non-destructive testing (NDT) • Check that a structure has been built according to the appropriate designs, procedures and standards • Check that a structure is being used appropriately for the environment designed for • Recommend and design modifications to address areas of concern Introduction to Working at Height Work at any height where there is a risk of a fall liable to cause personal injury unless precautions are taken. Workers at risk: Steel workers. Scaffolders. Roofers. Engineers. Welders. Maintenance staff. • Painters. • Windowcleaners. • • • • • • Main risks: Accidents: • Worker falling. • Object falling. • Death. • Neck or spinal injury. • Broken bones. • Brain damage. Vertical Distance • Falls from any height can cause injury. • Vertical distance is only one factor. • Falls of less than two metres can cause death or major injury! Risk Factors for Work at Height • Deterioration of materials. • Unprotected edges. • Unstable access equipment. • Weather. • Falling materials: ‒ ‒ ‒ ‒ ‒ ‒ Crumbling brickwork, loose tiles. Bad storage of materials on scaffolding. Bad housekeeping – accumulation of debris. Gaps in platform surfaces. Open, unprotected edges. Throwing things on and off the roof. Group Exercise What are the hazards of working at height for a window cleaner? Discuss the most effective way(s) to reduce the risk. Controlling the Risks of Work at Height Hierarchy of Controls Avoid work at height Prevent falls Minimise the distance and conseque nces of falls Prioritise collective protection over personal protection when applying the last two controls. Avoiding Work at Height • Modify the work process: ‒ E.g. work from ground level. • Modifying a design: ‒ E.g. change design of structure so that steel is assembled at ground level and craned into place. • May not be possible to achieve. Avoiding Work at Height Factors to consider when selecting control measures: • Nature and duration of • • • • • task. Competence of workers. Training needs. Planning and supervision needed. Means of access and egress. Suitability of equipment and its maintenance and pre-use checks. • PPE requirements, e.g. helmets. • Weather conditions. • Health of workers. • Need for a rescue plan. • Compliance with regulations. Preventing Falls and Falling Materials Proper planning and supervision of work is important to prevent falls from height and falling materials. Those responsible for such work should be experienced and should use their knowledge to ensure: The selection and use of correct access equipment. Correct provision and handling of tools and materials. Adequate information, instruction and training. Regular inspection of the workplace, work equipment and work methods. • Avoiding work in bad weather. • • • • Preventing Falls and Falling Materials Falls hierarchy: • Safe working platform. • Properly installed suspended access equipment. • Equipment to arrest falls. Falling materials: • Fit toe boards and brick guards. • If risk remains, debris netting and covered walkways. Guardrails and Toe Boards Guardrails: • • • • • Fully enclose the unprotected edge. Robust. Securely fixed. High enough. No large gaps. Toe boards: • Toe board fitted at edge. • Brick guards. Work Platforms • Large enough to allow safe use. • Capable to bear required loads. • Fully boarded. Suspended Access Equipment Suspended cradle: • Fully guarded, toe boards. Personal suspended access equipment: • E.g. boatswain's chair: ‒ Light, short-term work. ‒ Similar control to abseiling. Emergency Rescue • Reasonably foreseeable events. • Simple: putting up a ladder. • Mechanical access: Mobile Elevating Work Platform (MEWP). • Trained operatives. Fall Arrest • Collective protection systems – nets, airbags, soft bags: ‒ Best systems. ‒ Protect all workers. • Personal protective systems – fall arrest harness: ‒ ‒ ‒ ‒ Full-body harness. One or two lanyards. Anchor point. Training. Provision of Equipment, Training and Instruction • Workers should be trained to work at height safely. • Content of training depends on the nature of the work. • Workers should have an awareness of the hazards. • Additional training may be required by law for use of some equipment. Ladders Intended for short-duration work. Risks: • Falls from height: ‒ Falling off the ladder. ‒ The ladder toppling sideways. ‒ The ladder base slipping out from the wall. • Objects falling from height. • Contact with live overheads. Group Discussion Suggest the control measures for the safe use of ladders. Ladders • Sited away from live overheads. • Solid, flat base. • Weight supported on stiles, never on rungs. • Correct angle (1:4 rule – 75o). • Top of the ladder against solid support. • Ladder secured at the top; or: ‒ ‒ guy ropes attached or; ladder should be ‘footed’. Ladders • Top of the ladder should extend 1m (five rungs) above stepping off point if used as a means of access. • Only one person on ladder at any one time. • Nothing should be carried in the hands while climbing. • Maintain three points of contact. • Wooden ladders should not be painted. Stepladders Intended for short-duration, light work. Precautions: • Daily inspections before use. • Fully open. • Locking devices in place. • Firm, level ground. • Don’t work off top two steps. • Avoid overreaching. • Avoid side-on working. Inspection of Access Equipment Should be inspected: • When first erected. • After substantial alteration. • After incident affecting stability. Such as? • Periodically - typically every seven days. Inspection of Access Equipment Points to consider: • Condition of tubes (especially standards). • Tying and bracing. • Condition of the work platform. • Edge protection. • Ground conditions. • Safe access. • Safe working load. Prevention of Falling Materials Through Safe Stacking and Storage If housekeeping is not properly managed, it can: • Hinder safe movement around the workplace. • Block light. • Block access to essential services. • Stacks and piles can present danger of collapse. • Lead to stacked materials toppling over. Prevention of Falling Materials Through Safe Stacking and Storage Sufficient space needed for storage of materials: • Storage areas clearly defined. • Separate areas for different items. • Segregation of certain materials and substances, e.g. gas bottles. • Clean and tidy areas routinely inspected. • Appropriate warning signs. • No work activities in storage areas. Prevention of Falling Materials Through Safe Stacking and Storage When stacking: • Each stack for one material only. • Set maximum stack height. • Stacks should be vertical. • Use pallets to keep materials off the ground. • Allow space between stacks for safe movement. • Protect stacks from being struck by vehicles. Introduction to Confined Spaces “any place, including any chamber, tank, vat, silo, pit, trench, pipe, sewer, flue, well or other similar space in which, by virtue of its enclosed nature, there arises a reasonably foreseeable specified risk”…. Introduction to Confined Spaces …the foreseeable specified risks are: • Fire or explosion. • Loss of consciousness from gas, fumes, vapour, lack of oxygen. • Drowning. • Asphyxiation/ entrapment in free-flowing solid. • Loss of consciousness from increased body temperature. Factors to be Assessed • General condition of the confined space ‒ ‒ ‒ ‒ ‒ Previous contents . Residues. Contamination. Oxygen deficiency and oxygen enrichment. Physical dimensions. • Hazards arising from the work ‒ ‒ ‒ Cleaning chemicals. Sources of ignition. Increasing temperature. • Hazards from outside the space ‒ Ingress of substances. ‒ Emergency rescue. Safe System of Work for Entry • Do not work inside a confined space if possible. • Carry out a risk assessment. • Develop safe system of work. • Develop emergency arrangements. • Use permit to work. • Use only trained, competent personnel. Safe System of Work for Entry • • • • Supervision. Competency. Communication. Atmospheric testing/monitoring. • Ventilation. • Removal of residues. • Isolation, lock-off of in-feeds and outfeeds. • Isolation, lock-off of electrical/mechanical hazards. • PPE. • Access/egress. • Fire prevention. • Lighting. • Suitability of individuals. • Emergency/rescue procedures. Risk Assessment Factors for Lone Working Workers who are separated from their work colleagues. Lack assistance if things go wrong. Communication with colleagues more difficult, i.e.: • Out of eyesight. • Out of earshot. Safe System of Work for Lone Working • No lone working for high-risk activities, e.g. confined spaces. • Remote supervision. • Logging workers’ locations. • Mobile phones or radios. • Lone worker alarm systems. • Procedures for lone workers. • Emergency procedures. • Training for workers. Typical Risks Relating to Vehicle Movements • Loss of control: Due to driver error, environmental or mechanical reasons. • Overturning: Laterally or longitudinally. • Collisions: With other vehicles, pedestrians or fixed objects. Loss of Control and Overturning Factors that can cause a forklift truck to overturn: • Cornering while being driven too fast. • Uneven loading of the forks. • Driving over potholes. • Driving with the load elevated, especially cornering. • Uneven tyre pressures. • Driving across a slope (rather than straight up/down the fall line). • Excessive braking. • Collisions, especially with kerbs. Risk Factors Factors that can increase the risk of collisions: • Driving too fast. • Inadequate lighting. • Reversing without the help of a banksman. • Blind spots, such as corners and entrances. • Bad weather conditions (e.g. rain). • Obstructed visibility (e.g. overloaded forklift truck). • Poor design of pedestrian walkways and crossing points. • Lack of vehicle maintenance. Non-Movement-Related Hazards Typical non-movement-related hazards arise from: • Loading: manual and mechanical. • Overloading: exceeding the safe working load of the vehicle. • Unloading: tipping operations, etc. • Securing: to sheet a lorry. • Coupling: attaching trailers. • Maintenance work: working at height. Workplace Transport Control Measures • Eliminate the hazard. • Create a safe place. • Create a safe person. • Risk assessment: ‒ ‒ ‒ ‒ ‒ Identify the hazards. Identify the groups at risk. Evaluate the risk. Record and implement. Review. Risk Assessment Measures necessary to control risks created by vehicle operations can be grouped under: • Workplace environment. • Vehicle. • Driver. The Workplace Environment • • • • • Vehicle-free zones. Pedestrian-free zones. Traffic route layout. Segregation. Marked walkways and crossings • Separate access points. • Speed limits. • Vehicle movements managed. • Good visibility. • Signage. • Well lit, maintained roads/pathways. • Avoid gradients. • Barriers at changes in levels, e.g. loading docks. Group Exercise What controls could reduce the risks in areas where vehicles are reversing? The Workplace Environment Site rules for safe vehicle parking of a forklift truck: • Apply the handbrake. • Lower the forks and tip the mast forwards. • Remove the key. • Do not obstruct a traffic route. • Do not obstruct a pedestrian route. • Do not obstruct emergency escape routes. The Workplace Environment Control measures to reduce risk of accident from reversing vehicles: • Avoid reversing by using one-way systems. • High-visibility clothing. • Segregate pedestrians • Good lighting. and vehicles. • Banksmen. • Good visibility from • Training for drivers and vehicles. pedestrians. • Reversing alarms and beacons. • Mirrors to reduce blind spots. Risk Assessment Factors 1.Identify the hazards: ‐ ‐ ‐ ‐ ‐ Journey distance. Driving hours. Work schedule. Stress. Weather conditions. 2.Identify who may be harmed. 3.Evaluate the risks: ‐ ‐ ‐ Eliminate the need to travel. Travel by a safer means. If road travel take sensible precautions. 4.Record the findings. 5.Review. Evaluating the Risks If road travel is the preferred option then look at: • The driver. • The vehicle. • The journey. And base controls around these factors. The Driver Competency: • Drivers’ licences checked. • Experience and ability. Training: • Advanced or defensive driving courses. • Vehicle safety, pre-use inspection. Fitness and health: • Medical examination. • Eyesight checks. • Drugs policy. The Vehicle Suitability: • Minimum requirements, standards. • Insurance and valid regulatory certificate if private vehicles used. Condition: • Maintained. • Pre-use inspections. • Defect reporting. The Vehicle • Safety equipment: ‒ Seat belts, airbags, head restraints. ‒ Emergency triangles, first-aid kit, spare tyre. ‒ Fire extinguisher. • Safety-critical information: ‒ Tyre pressures, headlight and restraint adjustments, etc. • Ergonomic: ‒ Adjustability of seat position and posture. • Mobile phone use The Journey Routes Scheduling • Avoid hazards, e.g. town centres. • Avoid peak times. • Avoid fatigue times, e.g. 2–6am, 2–4pm. • Select low-risk roads, e.g. motorways. • Avoid roadworks. • Flexible deadlines. The Journey Time: • Realistic, e.g. route, weather, breaks. • Rest breaks. • Statutory requirements, e.g. lorry drivers (HGV). Distance: • Use other transport. • Not excessive. Weather conditions: • Reliable weather forecasts. • No driving/additional safety advice in bad weather. The Effects of Exposure to Noise • Construction workers: ‒ Plant, machinery, e.g. concrete breakers. • Uniformed services: ‒ Small arms and artillery. • Entertainment sector workers: ‒ Loud music. • Manufacturing sector workers: ‒ Industrial machinery. • Call centre staff: ‒ Acoustic shock from headsets. The Effects of Exposure to Noise Physical effects: • Temporary: ‒ ‒ Reduction in hearing ‒ Tinnitus. Noise-induced hearing loss (permanent threshold shift). ‒ • Stress. • Concentration problems. (temporary threshold shift). Ringing in ears (temporary tinnitus). • Permanent: ‒ Psychological effects: Inability to hear vehicles, Terminologies Terminology • Sound pressure: ‒ The number of pressure waves per ‒ The air pressure of second sound waves moving through the air. • A-weighting: Expressed in decibels ‒ Sound pressure level (dB). corrected to match • Decibel (dB): human hearing sensitivity. ‒ The unit of sound pressure level; • C-weighting: subjectively the ‒ Sound pressure level ‘loudness’. corrected for impulse • Frequency: noise. Decibel Levels Measurement in dB(A) 0 Sound Faintest audible sounds 20-30 Quiet library 50-60 Conversation 65-75 Loud radio 90-100 Power drill 140 Jet aircraft taking off 25m away Noise Exposure Standards The two factors which determine the degree of harm are: • Noise level. • Duration of exposure. A noise assessment is undertaken to measure noise levels and durations of exposure. This is then used to make an estimate of workers’ personal exposure to noise. Personal exposure is then compared to the legal standards. Measurements and assessment must be undertaken by a competent person. Noise Exposure Standards Personal noise exposure: ● The daily personal noise exposure (LEP,d) is a worker’s calculated 8-hour noise exposure. ● Worker’s exposure to single peaks of exposure (impulse noise) is also measured - this is the peak sound pressure. Noise Exposure Standards • Subject to national laws around the world. • No harmonised standards. • In the UK, these are laid out in the Control of Noise at Work Regulations 2005. • Follow EU directive. Noise Exposure Standards • Lower exposure action values: ‒ ‒ a daily or weekly personal noise exposure of 80 dB(A); and a peak sound pressure of 135 dB (C) for impulse noise. • Upper exposure action values: ‒ ‒ a daily or weekly personal noise exposure of 85 dB(A); and a peak sound pressure of 137 dB(C) for impulse noise. • Limit values: ‒ ‒ a daily or weekly personal noise exposure of 87 dB(A); and a peak sound pressure of 140 dB(C) for impulse Noise Exposure Standards: Actions Triggered Lower Exposure Action Value: 80 dB(A) LEP,d ● Carry out noise assessment. ● Provide information, instruction and training. ● Make hearing protection available. Noise Exposure Standards: Actions Triggered Upper Exposure Action Value: 85dB(A) LEP,d ● Carry out a noise assessment. ● Reduce noise exposure by engineering means, ALARP. If noise is still above 85dB(A): ● Mandatory hearing-protection zone. ● Information, instruction and training. ● Provide hearing protection and enforce use. ● Health surveillance. Noise Exposure Standards: Actions Triggered Exposure Limit Value: 87 dB(A) LEP,d ● Immediately prevent exposure and reduce below the limit value. The ELV is an absolute ceiling above which exposure must not go. Group Exercise A noise survey has been carried out and there are two work areas of concern: • Machine shop - noise levels 83 dB(A) throughout the shift. • Wood-working area - noise levels 90 dB(A) throughout the shift. Discuss the actions that would need to be taken in each area. Basic Noise Control Measures How Noise Travels from Source to Receiver Basic Noise Control Measures Reduce noise at source • Eliminate. • Substitute. • Modify the process. • Maintenance. • Damping. • Silencing. Interrupting the pathway • Insulation. • Isolation. • Absorption. Protect the receiver • Acoustic haven. • Hearing protection. Hearing Protection Ear defenders (muffs): • Encase the ear and bones surrounding the ear. Ear plugs: • Fit into the ear canal. Group Exercise Discuss the relative advantages and limitations of ear defenders (muff type) and ear plugs as forms of hearing protection. Hearing Protection Whichever type of hearing protection is chosen, arrangements should be made for: • Information, instruction, training. • Safe storage. • Cleaning. • Maintenance. • Replacement. Group Exercise Identify occupations at risk from noiseinduced hearing loss and the potential causes. Health Effects of Exposure to Vibration Hand-Arm Vibration effects: Hand-Arm Vibration Syndrome (HAVS) • • • • Vibration white finger (blanching). Nerve damage. Muscle weakening. Joint damage. Carpal tunnel syndrome. Typical vibration white finger (Source: HSE Guidance L140) (Reproduced under the terms of the Open Government Licence) Health Effects of Exposure to Vibration • Whole-body vibration effects: ‒ Back pain. • Occupations: ‒ Drivers. ‒ E.g. dumper truck driving. The Assessment of Vibration Exposure Control of Vibration at Work Regulations 2005 • Vibration ‘dose’ determined by: ‒ Vibration magnitude. ‒ Duration of exposure. • Personal exposure is estimated. • Called ‘eight-hour energy equivalent vibration magnitude’ or ‘A(8)’. • This is compared to legal standards. Vibration Exposure Standards The daily exposure action value is: • 2.5 m.s-2 A(8) for hand-arm vibration. • 0.5 m.s-2 A(8) for whole-body vibration. The daily exposure limit value is: • 5.0 m.s-2 A(8) for hand-arm vibration. • 1.15 m.s-2 A(8) for whole-body vibration. Vibration Exposure Standards At or above the daily exposure action value: At or above the daily exposure limit value: • 2.5 m.s-2 for HAVS, • 0.5 m.s-2 for WBV: • 5 m.s-2 for HAVS, • 1.15 m.s-2 for WBV: ‒ ‒ ‒ ‒ Vibration risk assessment. Reduce exposure level. Training. Health surveillance. ‒ ‒ Vibration risk assessment. Reduce exposure below the ELV. Basic Vibration Control Measures • Reduce vibration at source: ‒ ‒ ‒ ‒ Eliminate. Substitute. Change work technique. Maintenance. • Duration: ‒ ‒ • Person: ‒ • Interrupt the pathway: ‒ Isolate. Limit time exposed. Job rotation. PPE. Role of Health Surveillance At or above the exposure action value. Health surveillance allows: • Identification of workers with: ‒ Pre-existing vibration damage. ‒ New vibration damage. • Removal/exclusion of such workers from vibration sources. • Investigation of vibration sources to rectify problems. The Types of Radiation and their Health Effects Two types: • Non-ionising: ‒ Does not cause ionisation in the material that absorbs it. ‒ E.g. visible light. • Ionising: ‒ Does cause ionisation in the material that absorbs it. ‒ E.g. X-rays. Types of Non-Ionizing Radiation • Ultraviolet (UV): ‒ high-frequency, electromagnetic radiation (light) emitted by white-hot materials, such as the arc produced during arcwelding. • Visible light: ‒ electromagnetic radiation between the UV and IR frequencies and visible to the human eye. • Infrared (IR): ‒ lower-frequency, electromagnetic radiation (light) emitted by red-hot materials, such as molten metal being poured into castings. • Microwaves: ‒ lower-frequency, electromagnetic radiation emitted by a microwave generator. • Radiowaves: ‒ lower-frequency, electromagnetic radiation emitted by an Typical Occupational Sources of NonIonising Radiation Types Sources Health Effects Ultraviolet (UV) Sunlight Arc welding Skin burns Arc eye (photokeratitis) Skin cancer Visible light Lasers Temporary blindness Infrared (IR) Red-hot steel Glass manufacture Redness and skin burns, retinal burns, cataracts Microwaves Food preparation Telecommunication s Internal heating Organ damage Radiowaves Radio, TV Radar Internal heating Organ damage Group Exercise You are going on holiday to a hot country with long hours of sunshine. Discuss how you will protect yourself from sunburn from the UV light. Controlling Exposure to NonIonising Radiation Types Protection Ultraviolet (UV) ● Cover exposed skin ● Protect eyes Visible light, lasers ● Low class: avoid shining in eyes ● High class: eye protection, shielding, non-reflective surfaces Infrared (IR) ● Cover exposed skin ● Protect eyes Microwaves ● Safe distance ● Isolate and lock off Radiowaves ● Safe distance ● Isolate and lock off Types of Ionising Radiation • Alpha Particles ‒ Smoke detectors and science labs. • Beta Particles ‒ Science labs and thickness gauges. • X-rays ‒ Medical radiography and baggage security scanners. • Gamma-rays ‒ Industrial radiography for non-destructive testing of metal and welds. • Neutrons ‒ Nuclear power stations. Health Effects • Acute Health Effects ‒ ‒ ‒ ‒ Radiation sickness and diarrhoea. Hair loss. Anaemia (red blood cell damage). Reduced immune system (white blood cell damage). • Chronic Health Effects ‒ ‒ ‒ Cancer. Genetic mutations. Birth defects. Basic Means of Controlling Exposure to Ionising Radiation • Time ‒ ‒ Minimise exposure. Dose proportional to time. • Distance ‒ ‒ Alpha and beta can’t travel long distances through air. Other forms obey the inverse square law: double the distance = quarter the dose. • Shielding ‒ Using material such as lead. Group Exercise A pregnant woman is in need of an X-ray for a suspected broken bone. Discuss the control measures in the X-ray department of a hospital using: • time, • distance, • shielding, to structure your answer. Basic Means of Controlling Exposure to Ionising Radiation Ionising Radiations Regulations 2017 Dose limits on exposure: • General public < 1mSv per year. • Workers < 20mSv per year. The Regulations require that a risk assessment be carried out. This should be done by a competent person. A Radiation Protection Adviser and Radiation Protection Supervisors may need to be appointed. Basic Radiation Protection Strategies Basic protection strategies that apply in all cases: • Eliminate exposure so far as is reasonably practicable. • Reduce exposure to the lowest level reasonably practicable. • Do not exceed the relevant radiation dose limits. • Risk-assessed by a competent person. • Training and information. • Health surveillance. Role of Monitoring and Health Surveillance Types of examination include: • Skin checks. • Respiratory checks. • Exposure records. • Sickness records. Principles of Fire Fuel: A combustible material or substance consumed during the combustion process. Oxygen: From the air (which is 21% oxygen) or oxygen-rich substances (oxidising agents). Heat or ignition source: Energy to start the combustion process. Principles of Fire Fire is a rapid chemical process in which oxygen combines with another substance (‘fuel’) in the presence of a source of heat. This reaction is called combustion. During this reaction, heat, flames and smoke are produced. Classification of Fire This is the EU system. There is no formal Class E. ‘Electrical fires’ is used for electrical equipment. Principles of Heat Transmission and Fire Spread • Direct burning. • Convection: ‒ Inside. ‒ Outside. • Conduction. • Radiation. Principles of Heat Transmission and Fire Spread Convection Radiation Conducti on Group Exercise Suggest common causes of fire in the workplace. Causes • Electrical equipment. • Deliberate ignition (arson). • Hot work. • Smoking. • Cooking appliances. • Heating appliances. • Unsafe use and storage of flammable liquids and gases. • Mechanical heat. • Chemical reactions. Consequences • People killed and injured. • Damage to buildings and contents including smoke damage. • Environmental damage, e.g. water runoff. Control Measures to Minimise the Risk of Fire in a Workplace Control combustible and flammable materials: • Solids, liquids, gases. Control ignition sources: • Systems of work, smoking, arson. Use of electrical equipment in flammable atmospheres: • Hazardous area classification. Systems of work: • Hot processes, machinery, electrical equipment. Good housekeeping: • General tidiness, waste control and disposal. Control of Ignition Sources • Electrical equipment. • Hot work. • Smoking. • Cooking and heating appliances. • Mechanical heat. • Deliberate ignition. Systems of Work Permit to work for control of hot work: • Remove flammable materials from the area. • Cover items that can’t be removed. • Sweep the floor. • Damp down wooden floors. • Provide suitable fire extinguishers. • Ensure ‘fire-watcher’ present in the area. • Check area after work has finished. Good Housekeeping • Waste-free. • Tidy. • Well-ordered. • Pedestrian routes clear. Group Exercise Consider the storage of flammable liquids, e.g. acetone, petrol, etc. Discuss safe storage arrangements if such substances were used at work. Properties of Common Building Materials Concret e: Steel: Brick: Timber: Usually performs well in a fire. Severely affected by high temperatures. Usually very resistant. Thin timber will burn quite quickly; thick timber will survive for longer. Surface treatment can improve fire performance: • Encasing steel in concrete. • Intumescent paint. • Insulation. • Wall coverings. Properties of Common Building Materials Insulation: • Must be fire retardant. Wall coverings: • Can be flammable so need to be carefully selected. Protection of Openings and Voids Openings: • e.g. service conduits, air handling ducts. Voids: • e.g. stairwells, voids between floors, roof voids. Protection: • Self-closing shutters. • Fire break walls. • Procedure to seal any new openings, e.g. with fire-retardant foam. • Fire Detection and Alarm Systems Simplest system: ‒ Someone shouts ‘Fire!’ • Simple with more noise: ‒ Hand bell, whistle or air horn. • Manually operated fire alarm: ‒ Manual call points. • Interlinked smoke alarm: ‒ Links normally unoccupied rooms to interlinked smoke alarms. • Automatic fire detection and alarm: ‒ Automatic detectors, manual call points, linked to sounders/lights. The sophistication will depend on the complexity of Fire Detection and Alarm Systems Smoke detectors: • Detect small smoke particles. • Very sensitive, early warning. • Two main types: ionising and optical. • Can give rise to false alarms. Heat detectors: • Detect excess heat generated by a fire. • Less sensitive, later warning. • Two main types: rate of rise and fixed temperature. • May not detect fires that are giving off smoke but not much heat. Portable Fire-Fighting Equipment • Fire extinguisher. • Fire blankets: ‒ Physically smother fires, e.g. fat fires in kitchens. • Hose reels: ‒ Used in large buildings for fire teams. • Sprinkler systems: ‒ Sited in buildings and warehouses. ‒ Automatically dowses the fire. Extinguishing Media Siting, Maintenance and Training • On fire exit routes. • Close to exit doors. • Close to specific hazards. • Fixed to the wall or on stand/trolley. • Clearly visible. • Signed. • Unobstructed access. Siting, Maintenance and Training Inspection: • Regular and frequent to ensure they are: ‒ In place (firing pin). ‒ In good working order. Maintenance: • Ensure they remain in safe working order. • Once a year. • Certificated engineer. • Inspection, testing, dismantling. Siting, Maintenance and Training • Theory training. • Types of extinguisher. • Hands-on experience. • Records kept in line with local regulations. Access for Fire and Rescue Services The requirements for vehicle access differ depending on the: • Presence of fire mains. • Size of the building. • Type of fire appliance to be used. • For small buildings without a fire main, access for a pump appliance should be provided to 15% of the perimeter. • For large, high-rise buildings, the entire perimeter will need to be accessible. • Site should have an emergency plan including liaison with fire service. • Familiarisation visits may be carried out. Means of Escape • Available to every person in the workplace. • Does not require use of lifts (expect in special cases). • Must take person to a place of safety. • Two or more separate routes may be required. • Travel distance should be short. • Adequate width. • Clearly signed. • Appropriately lit. • Emergency lighting. • No obstructions. Travel Distances Depends on: • Number of people occupying a room. • Travel distance to nearest available: ‒ Final exit - to a place of total safety. ‒ Storey exit - into protected stairway. ‒ Separate fire compartment - containing final exit. • Fire risk. • Number of alternative escape routes available. Stairs and Passageways • Fire-resistant protection. • Adequate width: ‒ Consider wheelchair users. • Unobstructed. • No storage of materials or equipment. Doors • • • • Easy to operate. Adequate width. Open in direction of travel. Not locked. Emergency (Escape) Lighting • At night or where there is no natural light. • To indicate escape routes. • To indicate call points and fire-fighting equipment. • Regular maintenance. • Routine inspection/testing. Exit and Directional Signs • Standard shape. • Standard colour. • Pictogram. • Easy to interpret. • Clearly visible. Assembly Points • Safe distance from building. • Safe location. • Further escape possible if needed. • Must not impede fire-fighters. • Clearly signed. • 'Refuges' for disabled workers. Group Exercise Under your tutor’s direction, take a tour of an area of the building you are in. Note: • Fire compartment, e.g. stairwells, fire doors, etc. • Travel distances. • Fire detection and alarms. • Fire extinguishers, etc. • Emergency lighting, signage. Emergency Evacuation Procedures Emphasis is on personal safety: • Sound the alarm. • Get out of the building. • Stay out of the building. More complex procedures needed for some workplaces, e.g. hospitals. Fire Marshals Typical duties: • Check all areas are evacuated. • Assist disabled/infirm workers. • Ensure fire escape routes are kept clear. • Ensure windows and doors are closed. • Conduct roll call at assembly point. Roll Call • Ensure all persons accounted for. • May not be practical, e.g. supermarkets. • Provision for the Infirm and Disabled Staff with disabilities may need personal evacuation plans: ‒ Assist with travel downstairs. ‒ Alert those with hearing impairment. • May need to consider temporary disabilities, e.g. use of crutches. • Consider also evacuation of young/elderly. Building Plans and Emergency Escapes Fire plans should include: • Who is likely to be in premises. • Action to be taken on discovering fire. • Escape routes. • Fire-fighting equipment. • Action to be taken after evacuation. • Training. Training and Information Information on fire safety procedures for: • Employees. • Contractors. • Visitors and the public. Training for staff: • • • • Who use portable extinguishers. Fire marshals. Assist disabled or infirm people. Members of the fire team. Fire Drills • Usually once or twice a year. • Allows staff to practise procedures. • Allows for testing of those procedures. • Records kept. Forms of Chemical Agents • Solid. • Dust. • Fumes. • Gas. • Mist. • Vapour. • Liquid. • Fibres. The physical form greatly affects the hazard presented and the route of entry into the body. Forms of Biological Agents • Fungi: ‒ e.g. farmer’s lung. • Bacteria: ‒ e.g. Legionnaires’ disease, leptospirosis. • Viruses: ‒ e.g. HIV, hepatitis B. Acute and Chronic Health Effects Acute: Chronic: • Short-term effect. • Long-term effect. • High levels of • Lower levels of exposure. exposure. • Short exposure time. • Long exposure time, • Quick effect, e.g. e.g. multiple exposure to high exposures to concentration of asbestos. chlorine gas. Both acute and chronic effects: e.g. organic solvent, alcohol Classification of Chemicals Hazardous to Health • Physico-chemical effects: ‒ e.g. highly flammable, explosive or oxidising. • Health effects: ‒ e.g. toxic, carcinogenic. • Environmental effects: ‒ e.g. harmful to aquatic life. European Regulation (EC) No 1272/2008 on Classification, Labelling and Packaging of Substances and Mixtures (CLP Regulation). Classification of Chemicals Hazardous to Health • Acute Toxicity − Small doses cause death or serious illness. • Skin Corrosion/Irritation − Destroys living skin tissue or causes inflammation. • Serious Eye Damage/Eye Irritation − Destroys eye tissue or causes inflammation. • Respiratory or Skin Sensitisation − Causes asthma or allergic dermatitis. Classification of Chemicals Hazardous to Health • Germ Cell Mutagenicity − Causes hereditary genetic mutation. • Carcinogenicity − Causes cancer. • Reproductive Toxicity − Causes sterility or is harmful to unborn child. • Specific Target Organ Toxicity − Causes damage to specific body organs. • Aspiration Hazard − Harmful if inhaled into the lungs. Classification of Chemicals Hazardous to Health Sensitising agents (chemicals): • Respiratory sensitisers: ‒ Causes occupational asthma, e.g. flour dust, isocyanates. • Skin sensitisers: ‒ Cause allergic dermatitis, e.g. epoxy resin. Dermatitis: Non-infectious skin condition where the skin becomes dry, flaky, cracked and painful. • Primary Contact Dermatitis: ‒ Skin reacts at point of contact only, remove agent and skin recovers. • Allergic or Secondary Contact Dermatitis: ‒ Sensitisation reaction; dermatitis all over skin. Group Exercise How can a chemical or biological organism enter the body? Which is the highest risk route of entry and why? Routes of Entry • Inhalation: ‒ Inhalable dust (all particles). ‒ Respirable dust (only smaller particles). • Ingestion. • Absorption through the skin. • Injection through the skin: ‒ Needle-stick. ‒ Cuts and grazes. ‒ Bites. Defence Mechanisms The body has two main defence mechanisms to combat attack by biological agents and damage by chemicals: • Cellular (internal) defence – cells fight bacteria and other toxins from blood, respiratory and ingestion entry routes. • Superficial (external) defence – protects against toxins that enter through the skin and contaminants in the nose and throat. Assessment of Health Risks 1.Identify the hazardous substances present and the people who might potentially be exposed. 2.Gather information about the substance. 3.Evaluate the health risk. 4.Identify any controls needed and implement them. 5.Record the assessment and action taken. 6.Review. Assessment of Health Risks • Hazardous nature of substance. • Potential ill-health effects. • Physical forms. • Routes of entry. • Quantity. • Concentration. • Number of people. • Frequency of exposure. • Duration of exposure. • Control measures. Product Labels Set requirements: • Name of substance/mixture. • Hazardous components. • Risk phrases indicating danger. • Precautions. • Details of supplier. Group Exercise Safety Data Sheets Outline the type of information you would need to know about a domestic weed killer in order to assess the risks. Safety Data Sheets 1. Identification of substance and supplier. 9. Physical/chemical properties. 2. Hazard identification. 10.Stability and reactivity. 3. Composition of ingredients. 11.Toxicological information. 4. First-aid measures. 12.Ecological information. 5. Fire-fighting measures. 6. Accidental release measures. 7. Handling and storage. 8. Exposure controls/PPE. 13.Disposal considerations. 14.Transport information. 15.Regulatory information. Limitations of Information • Information sources provide general information only. • Don’t consider the specific conditions of use. • Individual susceptibility. • Mixed exposures. • Based on current knowledge. Occupational Exposure Limits • Around the world, there are different Occupational Exposure Limits (OELs) for hazardous substances: ‒ There is no global standard. • In the UK, they are called Workplace Exposure Limits (WELs). • They set a maximum limit of exposure that can’t be exceeded over a given time period. • WELs have legal status under the COSHH Regulations. Occupational Exposure Limits Definition of WEL: “The maximum concentration of an airborne substance, averaged over a reference period, to which employees may be exposed by inhalation” Short-Term and Long-Term Limits Term Short-Term Exposure Limits (STELs) Long-Term Exposure Limits (LTELs) Time period Reasons for limits 15 minutes Combat acute effects Very high exposure for a short time 8 hours Combat chronic effects Lower exposure over longer period The Purpose of Time-Weighted Averages A worker might be exposed to different levels of a hazardous substance throughout the working day. The STELs prevent them being exposed to harmful levels of the substance over short periods of time where this would cause acute effects. The LTELs prevent them being exposed to harmful levels over the full working day where this would cause chronic effects. Limitations of Exposure Limits Being below a limit does not prove it is safe: • Only concerned with inhalation. • No account of individual sensitivity or susceptibility. • No account of synergistic or combined effects. • Invalid if normal environmental conditions change. • Some limits do not consider all possible health effects of a substance. End of Module Exercise 1. What are OELs? What are they known as in the UK? 2. What is the difference between: • An 8-hour TWA? • A 15-minute STEL? Group Exercise A gardener is spraying a weed killer in a domestic garden in windy conditions. The gardener has no means of washing his hands, etc., and the house owners have children and a dog. The weed killer is an organophosphate labelled ‘toxic’. Using the ‘hierarchy of control’, discuss how the risk may be reduced. The Practical Control of Exposure • Elimination or substitution. • Process change. • Reduce exposure times. • Enclosure and segregation. • Local Exhaust Ventilation (LEV). • Dilution ventilation. • Respiratory protective equipment. • Other PPE. • Personal hygiene and protection regimes. • Health surveillance. Elimination or Substitution and Process Change • Elimination or substitution: ‒ Eliminate process, e.g. outsource painting. ‒ Change work, e.g. screw rather than glue. ‒ Dispose of unwanted stock. ‒ Substitute hazardous for non-hazardous, e.g. irritant to non-hazardous floor cleaner, or corrosive to irritant. ‒ Change physical form of substance to one that’s less harmful. • Process change: ‒ Apply solvent by brush instead of spraying. ‒ Vacuum rather than sweep. Reduce Exposure Times ● Double the time, double the dose; half the time, half the dose. ● Minimise the time period over which people are working with hazardous substances. ● Link to OELs. Enclosure and Segregation Enclosure: Segregation: • Totally enclose the substance. • Prevent access to it. • Keep people away. • Designated areas. Local Exhaust Ventilation Group Exercise Discuss how the effectiveness of LEV may be reduced. Effectiveness of Local Exhaust Ventilation Will be reduced by: • Poorly positioned intake hoods. • Damaged ducts. • Excessive amounts of contamination. • Ineffective fan. • Blocked filters. • Build-up of contaminant in the ducts. • Sharp bends in ducts. • Unauthorised additions to the system. Inspection of Local Exhaust Ventilation • Routine visual inspection: ‒ Integrity checks, e.g. filters, contaminant build-up, etc. • Planned preventive maintenance: ‒ e.g. replacing filters, lubricating fan bearings, etc. • Periodic testing: ‒ ‒ Ensure air velocities are adequate. COSHH requirement every 14 months. Dilution Ventilation • Diluting the contaminant. • Changes the air. • Passive dilution – vents. • Active dilution – powered fans. • Used where: – WEL is high. – Formation of gas or vapour is slow. – Operators are not close to contamination. • Important to know whether contaminant is lighter or heavier than air. Dilution Ventilation Passive Dilution Ventilation Dilution Ventilation Limitations are: • Not suitable for highly toxic substances. • Compromised by sudden release of large quantities of contaminant. • Do not work well: ‒ For dust. ‒ For point sources. • Dead areas may exist: ‒ Where there is little air movement. Respiratory Protective Equipment Two types: • Respirators: ‒ Filter contaminated air from the atmosphere around the wearer. • Breathing Apparatus (BA): ‒ Provide breathable air from a separate source. Selection, Use and Maintenance of Respiratory Protective Equipment Factors to consider: • Concentration of the contaminant and its hazards. • Physical form of the substance. • Compatibility with other items of PPE. • Shape of the user’s face. • Facial hair. • Level of protection offered by the RPE. • Physical requirements of the job. • Presence or absence of oxygen. • Physical fitness of the wearer. • Duration of time that it Selection, Use and Maintenance of Respiratory Protective Equipment Users should understand: • How to fit the RPE. • How to test it to ensure that it is working effectively. • The limitations of the item. • Any cleaning requirements. • Any maintenance requirements (e.g. how to

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