Occupational Safety and Health - Physical Hazards PDF

DRM2432 OCCUPATIONAL SAFETY AND HEALTH TOPIC 3 PHYSICAL HAZARDS  INTRODUCTION Physical hazards not only cause discomfort but affect safety, health and work efficiency. Although we can feel, see and hear these conditions, they are f...

DRM2432 OCCUPATIONAL SAFETY AND HEALTH TOPIC 3 PHYSICAL HAZARDS  INTRODUCTION Physical hazards not only cause discomfort but affect safety, health and work efficiency. Although we can feel, see and hear these conditions, they are frequently neglected. The nature of manufacturing industries develops many types of physical hazards such as heat, noise, lighting and electricity. To minimize the risk, many standards and guidelines have been developed by international bodies as well as our DOSH. At the same time, employers should provide additional preventive actions to protect their employees by customizing these guidelines to the industry's specific environment This course focuses on 3 most common physical hazards; fire, electricity and noise.  TYPE OF INDUSTRIAL HAZARDS Type of Physical Chemical Biology Ergonomics Psychosocial hazards ▪ Mechanical ▪ Gases ▪ Insect ▪ Posture ▪ Violence / Machinery ▪ Liquid ▪ Fungi ▪ Workflow ▪ Stress ▪ Thermal ▪ Solid ▪ Yeast ▪ Workstation ▪ Harassment ▪ Noise ▪ Vapours ▪ Bacteria design ▪ Bully Example ▪ Vibration ▪ Dust ▪ Viruses ▪ Poor ▪ Threat of of ▪ Fire ▪ Fumes ▪ Animals equipment danger hazards ▪ Electricity ▪ Pesticide ▪ Birds design ▪ Discriminati ▪ Radiation ▪ Mists ▪ Human ▪ Heavy lifting on ▪ Ventilation ▪ smoke ▪ Plants ▪ Repetitive ▪ Intense movement workload Energy form Substances Living Physical over- Mental over- form organisms burden burden 3 FIRE HAZARD  FIRE HAZARDS “Fire Triangle” identifies the 3 components of any fire: i. Oxygen : present in the air that supports combustion ii. Fuel : the substance that burns and exists in various forms of solid, liquids and gases (e.g. paper, wood & flammable gas) iii. Heat : the thermal energy required to cause fuel to ignite (e.g. a lighted match & ignites a piece of paper Removal of any of the 3 elements of the triangle will prevent a fire FIRE TRIANGLE Heat  PREVENTION Required knowledge for prevention; i. Properties of materials ii. Nature of fire and explosion process iii. Procedure to reduce fire hazards iv. Safe equipment approved by recognised international standards Fire prevention methods include: Heat and/or smoke detectors Automatic fire sprinkler systems Kitchen hood systems Building codes and materials Flame-retardant furnishings and materials (e.g. firedoor). Kitchen Hood Systems FIRE DRILLS Conduct fire drills in factory The fire drills should include staff & top management Highlights: Well equipped Emergency Control Centre Assembly sites identified and displayed Likely emergency scenarios identified & rehearsed Observers from senior management to be present (to further improve) Well laid out / written mock drill assessment sheet Review of rehearsal by Executive Director with senior management officials and observers, for identifying improvement areas Review immediately after the rehearsal. METHOD OF EXTINGUISHMENT Putting out a fire means isolating or removing any element of the fire triangle; STARVING Close valve Removal of Remove combustible item fuel supply Heat SMOTHERING Putting a lid Suffocates the Apply foam fire CO2 or dry foam Heat COOLING Water absorbs heat Lowering of readily thus cooling ignition the fuel temperature Heat Cooling is effective for solids fuels only. Water is a good cooling agent and when applied in fine spray can absorb a large amount of heat away from the burning fuel; All fires that have been extinguished by ‘starving’ and ‘smothering’ must be cooled with water. CLASSIFICATION OF FIRE EXTINGUISHMENT Fuels exist in 3 basic forms (solids, liquids & gases), and for this reason the extinguishing medium too differs according to the state of fuel: CLASS TYPES OF FIRE EXTINGUSHING MEDIA A SOLID COMBUSTIBLES Water & dry powder Eg: wood, paper, cloth , plastic etc… B FLAMMABLE LIQUIDS Foam & dry chemical Eg: petrol, alcohol, paint etc.. powder C GASES Carbon dioxide & dry Eg: LPG, LNG, hydrogen etc.. powder D COMBUSTIBLE METALS Special dry powder & Eg: magnesium, titanium etc… salts Most common types of portable fire extinguishers found in work areas are dry chemical powders & carbon dioxide. ELECTRICAL HAZARD  ELECTRICAL HAZARDS The use of electrical equipment and appliances is so common that most people fail to appreciate the hazards involved. Four principal categories of electrical hazards: i. Electric shocks ii. Ignition of combustible materials iii. Overheating or damage burns iv. Explosion i) Electric shocks Source of injuries are; i. Very high current (DC or AC); ii. Current path – e.g : arm to arm, fingers to foot; iii. High frequency value (causes tissue burning) iv. Duration of contact. ELECTRICAL HAZARDS & INJURIES ELECTRIC SHOCK AND BURNS 1 mA = detectable by touch 10 mA = Muscle contraction If the current passing through the chest, may cause: Asphyxia Fibrillation of the heart (vibration of the heart muscle) Disrupt normal rhythm of the heart Cardiac arrest Its depend on the environmental conditions at the time, as well as the age, gender, body weight and health of the person  Causes of a shock; Contact with a normally bare energised conductor Contact with insulation damaged conductor Equipment failure resulting in short circuit Static electricity discharge Lightning strike. ii) Ignition of combustible materials Commonest means: Spark or arc through a flammable mixture Protection Measures: Containment of discharges using inherently safe devices Encapsulation, embedment, and potting Hermetic sealing, liquid filling Explosion-proof equipment Pressurisation and isolation iii-overheating Effects of overheating: Raises the mixture to its auto-ignition temperature Causes materials to melt, char, or burn Causes rapid vaporization of liquid fuels iv-electrical explosions Causes of Explosion: Inadequate conductor size & heavy current. Short circuits, current surges. Other ways of electrical explosion. Prevention Fuse Improve circuit with fuses & circuit breakers Unit protection using thermal & magnetic relays. Resets: manual or automatic. Mini circuit breaker ELECTRICAL HAZARDS & INJURIES Procedure for treating unconscious person who receive low- voltage electric shock. 1. On finding a person suffering from electric shock, raise the alarm by calling for help from colleagues (including a first aider). 2. Switch off the power if it is possible and/or the position of the emergency isolation switch is known. 3. Call for an ambulance. ELECTRICAL HAZARDS & INJURIES Procedure for treating unconscious person who receive low- voltage electric shock. 4. If it is not possible to switch off the power, then push or pull the person away from the conductor using an object made from good insulator, such as a wooden chair or broom. Remember to stand on dry insulating material, for example, a wooden pallet, rubber mat or wooden box. If these precautions are not taken, then the rescuer will also be electrocuted. ELECTRICAL HAZARDS & INJURIES Procedure for treating unconscious person who receive low- voltage electric shock. 5. If the person is breathing, place him/her in the recovery position so that an open airways is maintained, and the mouth can drain if necessary. 6. If the person not breathing, apply mouth-to-mouth resuscitation and, in the absence of pulse, chest compressions. When the person is breathing normally place them in the recovery position ELECTRICAL HAZARDS & INJURIES Procedure for treating unconscious person who receive low- voltage electric shock. 7. Treat any burns by placing a sterile dressing over the burn and secure with bandage. Any loose skin or blisters should not be touched, nor any lotions or ointments applied to the burn wound. 8. If the person regains consciousness, treat for normal shock. 9. Remain with the person until they are taken to a hospital or local surgery. ELECTRICAL HAZARDS & INJURIES High-voltage electric shock. 1. Electrocution by high-voltage electricity normally instantly fatal. 2. When discovering a person who has been electrocuted by high-voltage, please inform police and electricity supply company. 3. If the person remains in contact with or within 18m of the supply, please do not approach until the supply has been switch off and clearance has been given by the emergency services. 4. High-voltage electricity can ‘arc’ over distances less than 18m, thus electrocuting the rescuer. NOISE HAZARD  NOISE HAZARDS Noise is an Unwanted sound! The commonest injury due to vibration is sound-induced hearing loss. The most important frequencies for speech understanding: 500 to 2,000 Hz. Hearing losses are greater resulting from higher frequencies rather than low frequencies. Safe hearing limit (No damage potential), even with long-term exposure when 80dB Adverse effects: Loss of hearing sensitivity Immediate physical damage (ruptured eardrums) Annoyance, distraction Contributions to other disorders Interference with other sound. Measuring Sound Levels Weighted Sound-Level Meters: Octave-Band Analysers Three weighting types classified as A, B, C are incorporated into the standard sound level meters. Reference : ICOP FOR MANAGEMENT OF OCCUPATIONAL NOISE EXPOSURE AND HEARING CONSERVATION  Noise exposure limit (OSHA Noise Exposure Regulations 2019) Employer to ensure none of his employees is exposed to: Daily noise dose exposure level exceeding 85 dB(A) or daily personal noise dose exceeding 100%, Maximum sound pressure level exceeding 115 dB(A) at any time, or Peak sound pressure level exceeding 140 dB(C) daily personal noise dose - the cumulative noise exposure of an employee corrected for a normal working day of eight hours Prevention i. Ear protection When noise levels exceed the OSHA standards, protection must be provided: eg. wool /cotton plugs, ear plugs & ear muffs ii. Eliminate Vibration & Noise Mount equipment on firm, solid foundation In fluid flow, keep velocity of fluids at lowest speeds possible (e.g. air- conditioning ducting) Avoid using quick-acting valves in liquid system Avoid pipe rattling Locate noise activities/equipment far from other operation iii.Isolate Isolate sources of vibration & noise : eg. using vibration isolators, sound-absorbing enclosures, etc. Isolate personnel: eg. arrange work schedules or check noise levels as often as reasonable. THE END