Industrial Hazards and Safety Precautions
Syllabus:
Mechanical, Chemical, Electrical, Fire and Dust hazards,
Industrial Dermatitis, Accident records etc.
MECHANICAL HAZARDS
Where Mechanical
Hazards Occur
Mechanical hazards occurs near any moving part of a machine.
(a) The point of
operation: that point where work is performed on the material, such as
cutting, shaping, boring, or forming of stock.
(b) Power transmission
apparatus: all components of the mechanical system that transmit energy to
the part of the machine performing the work. These components include
flywheels, pulleys, belts, connecting rods, couplings, cams, spindles, chains,
cranks, and gears.
(c) Other moving
parts: all parts of the machine which move while the machine is working.
These can include reciprocating, rotating, and transverse moving parts, as well
as feed mechanisms and auxiliary parts of the machine.
Hazardous Mechanical
Motions and Actions
A wide variety of mechanical motions and actions may present
hazards to the worker.
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Motions
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Actions
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Requirements for
Safeguards
Safeguards must meet these minimum requirements:
- Prevent contact: The safeguard must prevent hands, arms, or any part of a worker's body from making contact with dangerous moving parts. A good safeguarding system eliminates the possibility of the operator or another worker placing their hands near hazardous moving parts.
- Secure: Workers should not be able to easily remove or tamper with the safeguard. Guards and safety devices should be made of durable material that will withstand the conditions of normal use. They must be firmly secured to the machine.
- Protect from falling objects: The safeguard should ensure that no objects can fall into moving parts. A small tool which is dropped into a cycling machine could easily become a projectile that could strike and injure someone.
- Create no new hazards: The edges of guards, for instance, should be rolled or rounded in such a way that they eliminate sharp edges to prevent unwanted injuries.
- Create no interference: Proper safeguarding can actually enhance efficiency, since workers will not be afraid of injuries then.
- Allow safe lubrication: If possible, one should be able to lubricate the machine without removing the safeguards. Locating oil reservoirs outside of the guard, with a line leading to the lubrication point, will reduce the need for the operator or maintenance worker to enter the hazardous area.
ELECTRICAL HAZARDS
Electrical injuries consist of four main types:
electrocution (fatal), electric shock, burns, and falls caused as a result of
contact with electrical energy.
An worker will receive a shock when he/she
(i)
Touches two wires at different voltages at the same
time.
(ii)
Touches phase and neutral wire at a time
(iii)
Touches the phase standing on the ground
(iv)
Touches the phase having wet cloth, high humidity and
perspiration.
(v)
Receive a shock from electrical components those are
not grounded properly.
(vi)
Touching another person receiving an electrical shock.
Dangers of electrical shocks
The severity of injury
from electrical shock depends on the amount of electrical current and the
length of time the current passes through the body. For example, 0.1 ampere
(amp) of electricity going through the body for just 2 seconds is enough to
cause death.
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Current (milliampere)
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Effect
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Above 10mA
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Freeze muscle (muscles
become stiff)
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Above 30 mA
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Respiratory paralysis
(muscles those controls breathing cannot move)
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Above 75 mA
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Ventricular
fibrillation (very rapid, ineffective heartbeat)
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Above 5 Ampere
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Burning of tissues
occurs
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N.B. Currents above 10 mA can paralyze or “freeze” muscles. When this “freezing”
happens, a person is no longer able to release a tool, wire or other object.
The electrified object may be held even more tightly, resulting in longer
exposure to the shocking current. Current continues through the body for a
longer time can lead to respiratory
paralysis (the muscles that control breathing cannot move). Breathing will
be stopped for a period of time. Usually, it takes about 30 mA of current to
cause respiratory paralysis.
Currents greater than 75 mA cause ventricular fibrillation (very rapid, ineffective heartbeat). This
condition will cause death within a few minutes unless a special device called
a defibrillator is used to save the victim. Heart paralysis occurs at 4 amps,
which means the heart does not pump at all.
SAFETY
MEASURES
All
workplace has an electrical safety policy created by authority.
Electrical Safety Policy
The following items
should be included in the electrical safety policy:
(i) Power equipment should be plugged into wall
receptacles with power switches in the off position.
(ii) Electrical equipment should be unplugged by
grasping the plug and pulling. Never pull or jerk the cord to unplug the
equipment.
(iii) Frayed, cracked or exposed wiring on equipment
cords must be corrected. Also check for defective cord clamps at locations
where the power cord enters the equipment or the attachment plug.
(iv) Temporary or permanent storage of materials must
not be allowed within 3 feet of an electrical panel or electrical equipment.
(v) Any electrical equipment causing shocks or which
has high leakage potential must be tagged with a DANGER—DO NOT USE label or
equivalent.
Responsibilities of individual employee
(i) Training
and Education: Many accidents
are caused due to lack knowledge of the equipment or its operation. So
employees should be trained in electrical safety work practices and equipment
operation.
(ii) Hazardous
Condition Reporting: Employees
should always report unsafe equipment, conditions or procedures. Under no
condition should defective electrical equipment causing electrical shock be
used immediately.
(iii) Work
Practices: Employees are
responsible for following their employer’s safe work practices, procedures and
policy.
(iv) Housekeeping: Good housekeeping requires all employees to
observe activities that could cause electrical shock hazards. For example using
electrical equipment that is not properly grounded in areas that have water on
the floor can create shock hazards. Cleaning tools and electrical equipment
with solvents can create health and physical safety problems. Discarding rags
containing solvents into trash receptacles can create fire hazards as well.
CHEMICAL HAZARDS
Source of chemical hazards
1. Solvents used in extraction plants, purification of
synthetic drugs and in chemical analysis may produce vapors. This vapors or
gases may produce:
(i) Breathing
problem and suffocation to worker.
(ii) Irritation
or burn to eye or skin of the worker.
(iii) Explosion
in the work place.
(iv) General
anaesthesia or death e.g. chloroform and ether vapor.
2. Liquid chemicals if spilled on workers may produce
(i)
Dehydration by strong dehydrating agents e.g. concentrated
sulfuric acid.
(ii)
Burning by strong acid or alkalis.
(iii)
Oxidation by strong oxidizing agents.
3. Dusts of chemicals produced from different equipment may
produce
(i)
Dermatitis or dust allergies to the workers.
(ii)
Skin and eye irritations.
(iii)
Resistance to certain antibiotics e.g. resistant to
chloroform if the same worker is exposed to it regularly.
(iv)
Some dusts may be carcinogenic (producing cancers).
SAFETY MEASURES
1. Before
starting work with a chemical a “chemical hazard pocket guide” should be
consulted for necessary information about the chemical. It will give the type
of reaction the chemical may produce, its inflammability, carcinogenicity,
prevention and treatment procedures etc.
2. No
eating, drinking, or smoking where chemicals are used.
3. Skin
should be covered with protective clothing.
4. Clothing
should be removed immediately it gets wet or contaminated with a chemical.
5. Eyes
or skins should be washed with plenty of water after an accident.
6. Face
mask may be used in toxic dust or gases.
7. Workers
working in antibiotic related products must be changed routinely so that an
individual is not exposed to a certain antibiotic for a long period of time.
8. Whenever
a dust allergy or respiratory problem precipitates the worker should
immediately be removed from the work place and put under proper health care.
9. In
case of inflammable gas or solvent leakage the exhaust fans should be started
and all the source of fire should be extinguished.
DUST HAZARDS
Source of dust hazards in pharmaceutical industries
1. Grinding
or milling of drugs, excipients, or herbal products.
2. During
weighing dusts may float on air.
3. During
powder mixing dust s may be generated.
4. During
coating operation dusts are generated.
5. During
capsule filling and tablet punching operation dusts may be generated.
Methods of controlling dust
1. Filtration: Air is sucked through a
suitable filter medium (like paper, felt, wool, cotton-wool and nylon). Filter
bags can be attached with machines where dust is produced.
2. Inertial separator: In cyclone separator the air is circulated at
high speed in a spiral manner. Due to centrifugal force the dust particles are
thrown outward and the particles are collected at the bottom and the clean air
comes out through the top.
3. Electrostatic separator: It consists of
metal tubes though which a conductor wire is passed. Several thousand volts of
DC current is applied on the metal wire. When air is passed through the pipes
the dust particles becomes charged and precipitates on the inner wall of the
tube and clean air passes out. Periodically the dust is collected.
FIRE HAZARDS
Types of fire
Class A Fires: These are fires in
ordinary combustible materials such as wood, cloth, paper etc. those produce
glowing ember.
Class B Fires: These are fires of
flammable petroleum products, liquids, gases and greases etc.
Class C Fires: These fires involve
energized electrical equipment.
Class D Fires: These are fires in
combustible metals.
Fire Extinguishers:
Fire
extinguishing agents work by:
1. removal
of fuel e.g. blanketing with foam or interposing a layer of gas between the
fuel and the flames, or
2. by
removal of oxygen e.g. by dilution with inert gases or vapors, or
3. by
removal of heat by cooling with water or other extinguishing agents
Water based fire
extinguishers: They produce CO2 by reaction with acid and
carbonates, or CO2 is kept under pressure. E.g. Portable fire
extinguisher, Soda-Ash Extinguisher, Antifreeze Extinguisher.
Water
based foams: Two types of foams are available. Chemical foams and Mechanical foams. Chemical
foams are bubbles filled with CO2 produced by chemical reaction in
an aqueous solution mixed with a foaming agent. The reacting chemicals are
usually of sodium carbonate and ammonium sulfate. Mechanical foams are bubbles
filled with air. Foams forms barrier and prevents contact between fuel and air.
Dry
chemicals: These are finely divided solid particles usually discharged
through a hose pipe. Usually they contain sodium bicarbonate, potassium
bicarbonate and ammonium sulfate.
Halon
1301: It is Bromotrifluoromethane, which is liquefied compressed gas. It
produces cooling action and dilution of fuel vapors and air.