Hazard: A hazard in anything in the work place that has the potential to harm people. It includes objects in the workplace such as machinery or dangerous chemicals.
Types of hazards : 1) Mechanical hazards 2) Electrical hazards 3) Noise hazards 4) Radiation hazards 5) Explosion hazards 6) Toxic hazards 7) Chemical hazards
1.Radiation hazard: The radiation is produced when atoms of natural radio active material decay or split, generating streams of photons vibrating at enormous speeds in wavelike form. Radiation has two basic forms: ionizing and nonionizing. In chemical plants workers may be exposed to various forms of nonionizing radiation. Radiation hazards occurred during testing of nuclear weapons, establishment of nuclear power plants, mining and refining of plutonium and thorium and preparation of radioactive isotope.
Sources of radiation hazard:
1.Natural sources: They are mainly of cosmic radiation received from from the space, and the naturally occurring radioisotopes present in the environment and those contained within the body of the organisms. Another source is the presence of radionuclides in the lithosphere, hydrosphere and atmosphere.
2. Man made sources:
1. Nuclear weapons
2. Atomic reactors and nuclear fuel
3. Radioactive isotopes
4. Hospital (X-ray division)
2.Noise hazard: Un wanted sound is called noise. Sound levels that cause hearing loss begin at 85 db. Hearing loss occurs more quickly with louder noise. High sound levels cause serious health risks. Hearing damage results from an exposure to loud noises over an extended period of time.
Effect of noise on human being : High sound levels pose serious health risk to the people who work long hours around the equipment which generate high noise levels. Hearing damage results from an exposure to loud noises over an extended period of time. Deafness and loss hearing usually occur with the high frequency sound and not be lower frequency sound. Hearing is lost as auditory nerve endings are exposed to the same frequency of sound for extended time periods. The nerves lose their ability to recover from that hostile frequency. The ability to hear that sound frequency is then decreasing forever. Hearing loss accumulates over time and cannot be revers. Hearing aid assistance may be necessary.
Protection of noise hazard: i) Reduction at source: wherever possible it would be advisable to reduce the noise at the source itself.eg change the bearings if it makes noise due to wear. ii) Vibration isolation: In case of machine like reciprocating compressors and power presses, the mechanical vibrations are transmitted through the structures, walls and the floor which increases the noise level at the workplace. Reduction of noise levels can be achieved by, a) Using vibration resilient mounts to fix the machine to foundations. b) Special heavy foundations with a large weight compared to the weight of machine. iii) Vibration Damping:Machine parts, ventilation duct cause noise in this manner. Thenoise in these cases can be reduced by damping- by stiffening the member. iv) Silencers: Where noise due to movement of gases or air is the problem, silencers are the right solution. Silencers can be used at the inlet/outlet of compressors, exhausts, release of steam and gases and pressure relief valves of pneumatic machines. v) Noise insulation:It may be necessary to insulate the source from all the sides although insulating two or three sides also give reduction of a lower degree. vi) Noise absorption: Noise absorption material, normally soft and porous, prevent reflection of noise and also convert some of the noise energy into heat energy.
3.Electrical hazard: The danger of injury through electrical shock is present when ever electrical power is used. All electrical should be adequately insulated, grounded or isolated to prevent bodily contact with any source of dangerous potentials. To prevent electrical shock, ensure that all equipment is properly grounded. To reduce the risk of shock , do not contact any electrical components and keep your work area dry. Check all equipment regularly and wear the proper protective equipment when working with high voltages or currents. Electrical burns occur when the body completes a circuit connecting the power source with the ground. Although the resistance of dry, unbroken skin to electric current is relatively high, the amount of current necessary to kill person is small. Therefore it is easy to exceed lethal levels of current flow, especially if the skin is broken, wet or damp with sweat.
Common sources of electrical hazards : The danger of injury through electrical shock is present whenever electrical power is used. The primary effect of electric shock are due to current actually flowing through the body. Electrical burns occur when the body completes a circuit connecting the power source with the ground.
Potential sources : 5. Voltages between phases and between phases and neutral. 6. Voltages between phases, neutral and earth where there is any conductive surfaces. 7. Voltages across open switch contacts. 8. Voltages across undischarged capacitors. 9. Voltages on disconnected conductors. 10. Voltages caused by static electricity. 11. Incorrect wiring connection. 12. Faulty equipment.
4.Mechanical Hazard: In a chemical plant, welding and cutting are seldom done were mechanical hazards are occurred. The use of or the closeness to, mechanical equipment can present hazards to the welder. Knowledge of the proper use of power tools, such as grindess, chippers, drills and various hand tools, is important to welder safety. Moving parts of machine if not properly guarded can cause mechanical hazards. During handling of sharp heavy, rough and hot materials, suitable hand gloves and pads must be used to avoid mechanical hazards. In chemical plant to avoid mechanical hazards machines must be stopped and locked in stationary position before being oiled, lubricated or adjusted.
5.Explosion Hazard : Explosive substances include any material for making any explosive substance, also any apparatus, machine or material used with any explosive substance.