BOSH

• Engineering Controls


  • Eliminate the hazard by considering safety and health provisions, substitution, modification of process/equipment, isolation, wet methods and industrial ventilation
  • Most effective in preventing or reducing work environment factors or stresses
• Proper design and planning


  1. Initial consideration regarding safety and health aspects must be made in the planning and construction stage

  2. Correct identification of the problem and careful evaluation should be ensured

  3. Intervention or control measure to be employed must be the most cost effective
• Substitution/replacement of materials


  Substitution of non-toxic chemicals for the highly toxic ones
• Substitution of materials


  • Paints containing toxic chemicals like benzene, toluene di isocyanate (TDI) and other toxic organic solvents replaced by safer non-toxic substitutes (from solvent based to water based paints)
• Modification in the process/equipment


  1. Change in the process to improve working conditions

  2. Automation to lessen worker's exposure to the contaminant

  3. Use of lids to prevent dispersion of dust during mixing
• Isolation


  • Hazardous operations should be isolated to minimize exposure of workers
  • Physical barrier, such as acoustic panels, to minimize noise transmission
  • Worker may be isolated or enclosed in a soundproof control booth with a clean source of air supplied
• Wet methods


  • Applying water or other suitable liquids to minimize airborne dust hazards
  • Dampening powder materials or suppressing dust generation through misting or spraying of water
• Industrial ventilation


  • Supplies fresh air and/or removes contaminant laden air by natural or mechanical means
  • Provides workers with a comfortable working condition
  • Renews the air in the workplace, diluting eventual air contaminants to acceptable levels
  • Prevents hazardous air contaminants from reaching the workers breathing zone
• Types of Ventilation

  • General Ventilation (Mechanical and Natural)
  • General Exhaust Ventilation
  • Dilution Ventilation
  • Local Exhaust Ventilation (LEV)
• General Ventilation


  Used when: only small quantities of air contaminants are released, sufficient distance between worker and contaminant source, no air cleaning device, no corrosion or damage to equipment
• General Exhaust Ventilation


  A system normally used to remove hot air and other airborne contaminants in a general work area
• Dilution Ventilation


  Using fresh air supply, a fraction of air is introduced into the workroom such that airborne contaminants or heat are diluted to levels not harmful to health
• Local Exhaust Ventilation (LEV)


  • Removes air contaminants generated or dispersed from the work process before they can reach the breathing zone of the workers in harmful concentration
  • Most efficient engineering control measure for airborne chemical agents and particulates
• Principles of LEV

  • Enclose the contaminant
  • Capture contaminant with adequate air velocities
  • Keep contaminant out of the worker' breathing zone
  • Discharge exhausted air outdoors
• Basic Elements of LEV

  • Hoods
  • Duct work
  • Fan and motor
  • Air cleaning device
  • Exhaust stack
• Classifications/Types of hood

  • Enclosure-type
  • Exterior type
  • Receiving type
• Administrative Controls


  • Control employees' exposure by scheduling hazardous work process, reduced working hours, assigning workers to other less hazardous work areas, training of workers
• Administrative Control Measures

  • Reduction of work periods
  • Adjusting work schedules
  • Job Rotation
  • Education of supervisors
  • Employee information and training
  • Emergency response training and education
  • Housekeeping and maintenance
• Personal Protective Equipment (PPE)


  • Should be considered as the last resort when engineering controls are not feasible or are not sufficient
  • PPEs protective devices have one serious drawback - they do nothing to reduce or eliminate the hazard
• Situations where PPE should be used

  • Temporary control measures before engineering controls installed
  • Where engineering controls are not practicable
  • To supplement engineering controls in reducing exposure during maintenance and repair
  • During emergencies
• Types of Respirators

  • Air-purifying respirators (Mechanical Filter, Chemical Cartridge, Combination, Gas Masks, Powered Air-Purifying)
  • Air-supplying respirators (Self-Contained Breathing Apparatus)
• Selection of respirators

  • Identification of contaminants
  • Maximum possible concentration of contaminants
  • Acceptability in terms of comfort
  • Compatibility with the nature of the job
  • Proper fit to the face of the user to prevent leakage