Please enable JavaScript.

Coggle requires JavaScript to display documents.

Lab WS - Coggle Diagram

- - - - higher pitch harder to hear than lower pitch
      - hard to differentitate s,ch,sh,th sounds
      - often hear people mumbling
      - degree of hearing loss is the same for both ears
      - equivalent sound pressure
        
        the constant level of sound that cause same hearing damage risks as a varying sound
    - - eliminate(completely remove noisy process)
        
        difficult due to technical constraints
      - substitute(sub noisy process with less noisy one)
        
        idk
      - engineering
        
        noise barriers
        
        noise enclosure (15dB)
        
        noise curtain (5dB)
        
        noise panel (10dB)
        
        modify source of noise
        
        reduce vibration
        
        Reduce driving force
        
        maintain dynamic balance
        
        reduce velocity of rotating device
        
        reduce response
        
        add dampings(water/foam)
        
        work on stiffer surface
        
        reduce surface area of work surface
        
        Reduce veolicty and turbulence
        
        laminar flow is quieter than turbulent flow
        
        buy quieter equipment
      - Adminsitrative
        
        workers that are exposed to over the limit will go to area that is lower than initial noise level(safer one)
        
        Do not operate machine at full capacity
        
        commence noisy process at a time period when workers at minimum number(e.g at night)
      - reduce exposure time
      - Reduce noise level
      - PPE
        
        ear bands/plug and muffs
  - - - Fuel
        
        solid
        
        textile, plastic, dust, flour, sugar, paper, metal
        
        liquid
        
        petrol, diesel, alcohol, cleaning agents, solvents
        
        gas
        
        hydrogen gas, natural gas, liquefied petroleum gas
      - Oxidiser
        
        oxygen, oxidising agents
      - Ignition source
        
        wielding archs, frictional sparks, hot surfaces, open flames, lighted cigarettes, static electricity, electrical equipment
    - - the minimum temperature in which sufficient vapour is given off and mixed with air to sustain ignition (ignition source may not be near in order to ignite)
      - Flammable liquid(very low flash point)
        
        can ignite as vapour is easily given off and mixed with the air to sustain or start a fire
      - Combustible liquid (low flash point)
        
        capable to ignite but requires a higher temperature than flammable liquid
      - Flammable limit(aka explosive limit)
        
        shows the range of the minimum or maximum concentration of vapor needed to ignite a fire (must be within range)
        
        above UFL
        
        Too rich to burn( gas push O2 molecules away, thus insufficient O2 to ignite)
        
        Below UFL
        
        Too diluted to burn(insufficient fuel to burn)
    - - A(flammable solid)
        
        dry chemical/powder fire extinguisher
        
        Common materials (monoammonium, sodium, phosphate bicarbonate)
        
        Function
        
        Blanket effect: form a physical barrier and cover combustible materials to prevent spreading and cut off O2 supply
        
        Pros
        
        Versatile
        
        Fast fire-extinguishing ability
        
        Forms a screen between person and fire, thus allowinh person to approach closer to fire, more effective fire fighting
        
        Cons
        
        corrsosive and sticky residue which can damage electrical equipment, difficult to clean
        
        breathing in powder can cause health problems
        
        water fire extinguisher
        
        Cooling effect- reduce heat and decrease temperature of the surrounding to below ignition point, thus cannot sustain ignition
        
        Cons
        
        conductive- not suitable for electrical fires(can cause damage to equipment and shock hazard)
        
        Not suitable for combustible metals as it can react violently with water and cause an explosion
        
        not suitable for B fires as water is denser than gas and oil, thus cannot form a barrier to cut off O2
        
        Pros
        
        High fire extinguishing capacity( by reducing heat specific capacity and latent heat of vaporisation)
        
        Easy to refill
        
        Foam fire extinguisher
        
        provides surfactant that generates water based foams.(blanket and minor cooling effect
        
        Pros
        
        higher fire extinguishing capacity than water
        
        useful for oil based fires as it can float to the top of oil and cover the oil, thus cutting off O2 supply
        
        Cons
        
        contains water which can cause damage to electrical equipment(not suitable for electrical fires0
        
        common is aqueous film-foaming foam fire extinguisher-> contains fluorine compounds which pose health and environmental problems
      - B(flammable liquid)
        
        Carbon dioxide fire extinguisher
        
        Cooling effect- discharge ino vapors which boils and reduce heat to below its ignition point and thus cannot sustain ignition
        
        reduce O2 by dilution or displacement, thus reduce O2 supply to point that it cannot sustain ignition
        
        Pros
        
        spread over fire and extinguish it
        
        is inert and thus suitable for electrical fires
        
        easily liquefied and bottled under pressure which can be stored for weeks
        
        Cons
        
        when leak, can cause asphyxiating environment
        
        it has a short range(need to go closer to extinguish fire)
        
        short fire extinguishing capability and low cooling capacity-> not useful for large fires and not economical for A fires
      - C(flammable gas)
      - D(combustible metal)
      - E(fire involving cooking appliances)
      - VICES to prevent fire
        
        Ventilation
        
        Good ventilation rapidly disperse dangerous flammable vapours given of by leak, spill or any process
        
        To ensure that vapour concentration is not on the flammable limit range which is capable of ignite
        
        Install fans/ local exhaust ventilation systems (used when handling flammable items
        
        Ignition
        
        Remove any sources of ignition, especially during handling or storage
        
        To help break fire triangle
        
        Containment
        
        Contain flammable substances or its spills in a suitable manner
        
        use lidded containment or spillage trays to prevent spillage spreading to prevent flammable vapours to be given off
        
        Exchange
        
        Completely remove flammable process(elimination)
        
        Substitute flammable material/substances to a less flammable substances/materials(substitution)
        
        Consider other ways to make proccess more safe(engineering, administrative/PPE)
        
        Separation
        
        separate flammable processes/substances by the use of a physical barrier, practitioners, walls, container
        
        Storage of fire cabinet(1Hr fire cabinet) away from general cabinet)
  - - - laceration wound
    - - amputation/severe injuries
    - - Machine guards
        
        rigid physical barriers that enclose dangerous areas and restrict operators access to dangerous areas
        
        Fixed
        
        Adjustable
        
        Interlocking
      - Safety presence devices
        
        Anti-fatigue
        
        pressure sensor device
        
        When machine detect weight, switch closes and sent a signal to stop the machine
        
        safety camera
        
        monitors surrounding of dangerous areas
        
        warning zone
        
        If person step into warning zone, camera detects and sent a signal to system to set an alarm and slow/shut down machine
        
        danger zone
        
        Emergency stop
        
        for imminent/hazardous incidents
        
        When button is pressed, the power source will shut down->machine to shut down and thus prevent escalation of serious accidents
        
        Need to reset to normal in order for normal procedures to resume
        
        2 handed-control device
        
        requires both hands to touch in order for machine to work to prevent hand from entering the machine
    - - Announce lock down
        
        Commence lockdown
        
        Apply lockout, tag out
        
        Verify isolation and lock out
        
        Turn the switch on and check if machine still opeates, if not, turn off switch and procede with maintainence
        
        isolate energy sources with energy isolation device. ensure that any stored energy is dissipated
        
        affix double tag of the identities of people doing the lock out
        
        warning that activity related to machinism going to occur
        
        Procede with normal lock down measures
        
        Notify workers of lock down
  - - - defective electrical equipment
      - wire laying on wet floor
      - overloaded plug/circuit
      - damaged electrical cords
      - Reversed polarity
        
        when live and neutral wire position is switched
        
        machine will still run even when switch is turned off
        
        can be a shock hazard without melting the fuse
      - improper wiring of cord gripper
      - short circuit
        
        the unintended resistance between 2 electrical points of a circuit which bypass the normal load or circuit
        
        occurs when
        
        exposed live and netural wire touch before current can pass through the equipment
        
        when exposed live wire touch the metal casing of the equipment, causing the current to flow to the earth wire(if have)
        
        which can cause
        
        damage to power source
        
        fires and explosions
        
        electroceution and electric shock hazard
      - Earth wire
        
        When there is no earth wire, the current will flow to the worker when his hand or body part touches the equipment(complete circuit)
    - - ensure surface of work and hands are dry before electrical work
      - place rubber mat below metal ladder to stop current
      - wear electrical insulated gloves
    - - live (brown)
        
        supply current from source to equipment
      - neutral(blue)
        
        supply current from equipment to source
      - earth(green/yellow)
        
        transport current to the ground when short circuit occurs (safety feature
  - - - Keep at easy reach
        
        Work at proper heights
        
        Work at proper posture
        
        Minimise fatigue
        
        Reduce excessive force
        
        Reduce excessive movement
        
        2 more items...
        
        Excessive and unnecessary force can cause fatigue and injury
        
        1 more item...
        
        do not overload people's capacity and watch out for static load
        
        take breaks and stretch body from time to time to release stress
        
        awkward or contorted posture can increase physical stress and reduce strength
        
        Sit upright, follow the natural s curve of the spinal column, do not twist body or neck for extended period of time, no forward head position
        
        Mismatch heights between worker and table can cause awkward or contorted positions which can cause fatigue.
        
        adjust table/ chair to a comfortable height
        
        long stretches can strain the body
        
        keep frequently used items at easy reach
    - - aching feet, calluses, corns, blisters, malformation of toes, fallen archs(flat feet), strains and sprains.
      - Cause by
        
        long periods of standing
        
        Misfit shoes
        
        Hard flooring
        
        Wrong type of footwear
      - Solutions
        
        Stee-toed hard safety boots
        
        anti-fatigue mat(provides cushion to feet)
    - - monitor at arms length away
      - adjustable chair
      - Lower back supported by chair or cushion
      - eye leveled at upper part of the monitor
      - minimise bend at wrists
      - minimise obstructions below desk to allow postural change
      - Sit at an upright position, head aligned to the torso