3. Risk Control Hierarchy of Control Measures It is essential for risks to be controlled. This is usually by elimination or reduction “at source”. If a risk cannot be controlled completely by engineering measures, it is necessary to protect the employees by administrative control or personal protection. The control of hazards and reduction of risks can be accomplished by following the hierarchy of controls. These control measures are not usually mutually exclusive e.g. engineering controls can be implemented together with administrative controls like training. Preference Control Measure Examples Very High ELIMINATION Use water based The total removal of the hazards. If the solvents instead of hazards are eliminated, the risk associated of organic based the hazard will be eliminated. solvents. High SUBSTITUTION Use toluene instead This involves replacing the hazard by one that of benzene. presents a lower risk. Preferred ENGINEERING Fume Cupboard Engineering controls are physical means that CONTROLS glove boxes limit the hazard. These include structural changes to the work environment or work processes, erecting a barrier to interrupt the transmission path between the worker and the hazard. Satisfactory ADMINISTRATIVE Work instruction. These reduce or eliminate exposure to a CONTROLS Tight laboratory hazard by adherence to procedures or setup. Training on instructions, including training. hazards of organic Documentation should emphasize all the solvents. steps to be taken and the controls to be used in carrying out the activity safely. Least PPE Use of safety This should be used only as a last resort, after eyewear plus all other control measures have been respiratory considered, or as a short term contingency protection. during emergency / maintenance / repair or as an additional protective measure. Often this is used as secondary protection or general protection to third party users. The success of this control depends critically on the protective equipment being chosen correctly, fitted correctly, worn at all times and maintained properly. Table 5: Hierarchy of Control Measures
3. Risk Control Hierarchy of Control Measures It is essential for risks to be controlled. This is usually by elimination or reduction “at source”. If a risk cannot be controlled completely by engineering measures, it is necessary to protect the employees by administrative control or personal protection. The control of hazards and reduction of risks can be accomplished by following the hierarchy of controls. These control measures are not usually mutually exclusive e.g. engineering controls can be implemented together with administrative controls like training. Preference Control Measure Examples Very High ELIMINATION The total removal of the hazards. If the hazards are eliminated, the risk associated of the hazard will be eliminated. Use water based solvents instead of organic based solvents. High SUBSTITUTION This involves replacing the hazard by one that presents a lower risk. Use toluene instead of benzene. Preferred ENGINEERING CONTROLS Engineering controls are physical means that limit the hazard. These include structural changes to the work environment or work processes, erecting a barrier to interrupt the transmission path between the worker and the hazard. Fume Cupboard glove boxes Satisfactory ADMINISTRATIVE CONTROLS These reduce or eliminate exposure to a hazard by adherence to procedures or instructions, including training. Documentation should emphasize all the steps to be taken and the controls to be used in carrying out the activity safely. Work instruction. Tight laboratory setup. Training on hazards of organic solvents. Least PPE This should be used only as a last resort, after all other control measures have been considered, or as a short term contingency during emergency / maintenance / repair or as an additional protective measure. Often this is used as secondary protection or general protection to third party users. The success of this control depends critically on the protective equipment being chosen correctly, fitted correctly, worn at all times and maintained properly. Use of safety eyewear plus respiratory protection. Table 5: Hierarchy of Control Measures