Risk Control Mechanisms Evaluation

In order to evaluate the various potential controls mechanism types the advantages and disadvantages of the different control mechanisms should be taken into account in the process of deciding on the appropriate mechanism.

The following is a summary of the advantages and disadvantages of some of the most popular control mechanisms used by companies.

• Design to eliminate the energy source

This implies that a design or action is introduced to virtually eliminate the risk by removing all the energy.

Examples are the replacement of a potentially carcinogenic chemical with a non-carcinogenic one, and the use of incombustible materials in a fire risk area.

Advantages:

- The risk is reduced to virtually zero.

- A risk reduction measures taken at design stage can be a low-cost method.

Disadvantages:

- The change may introduce other risks that must be identified, assessed and controlled. This can be costly if the system is beyond the design stage.

- It is not possible in many situations to utilize this methodology.

• Design to reduce the energy source.

This approach requires that a design or action to greatly reduce the risk by reducing or controlling the energy be implemented. Examples are the reduction of on site chemical stocks, issuing smaller quantities from stores, and the application of fire retardant coating to materials where fire is a hazard.

Advantages:

- The risk, i.e. likelihood of the event or its consequences, is greatly reduced.

- Risk reduction measures taken at the design stage can be low cost.

Disadvantages:

- The residual or remaining risk may still be unacceptable.

- The change may introduce other risks that must be identified, assessed and controlled and this can be costly if the system is beyond the design stage.

• Installation of a safety device

A design or modification involving a physical barrier or device that does not rely on human action and is intended to protect targets from unwanted energy flows is installed to arrest the energy source when it goes out of control. Examples are the installation of earth leakage devices on electrical equipment, and an automatic fire suppression system.

Advantages:

- The risk can be significantly reduced if the device is reliable.

- It can be a cost effective method of reducing risk at any stage in the life of the system.

Disadvantages:

- The residual or remaining risk may still be intolerable.

- There may be a tendency to rely too much on an automatic safety barrier and not recognize the need for a second effective barrier for the risk.

• Installation of warning devices

The installation of warning devices that alert personnel, and others, of a potential or existing unwanted energy release in time to allow people to take remedial action or escape is another method of instituting controls. Such controls have two components, the warning and the procedure to be followed should the warning be given. Examples are the beeper on a large reversing vehicle that alerts people to stay out of the area, and a fire alarm and an evacuation procedure.

• Advantages:

- The risk is somewhat reduced.

- It can be a low-cost method of reducing risk at any stage in the life of the system.

• Disadvantages:

- The residual or remaining risk will still require further control.

- The likelihood that personnel will respond to the alarm depends on factors such as the complexity of required response, stress and employee perceptions( i.e. if the alarm is often heard it may be consciously or unconsciously ignored).

• Use of personal protective equipment, procedures and training

Procedures and training intended to reduce personnel risks, including actions and equipment intended to protect the person from exposure to an unwanted energy release is normally introduced as the last resort to controlling risk. Examples are respiratory protection equipment such as portable breathing apparatus, and work permit systems.

• Advantages:

- All employees must be trained in the tasks they are perform and in dealing with the risks related to the task.

- It is usually easy to implement and has low costs.

• Disadvantages:

- This is the least effective means of control because of its reliance on human behaviour and work site culture for success.

- The likelihood of effectiveness greatly depends on the quality of the equipment, whether it is used properly and whether the standard work practices are monitored.

- Personal protective equipment imposes restrictions on wearers, e.g. it may also reduce hearing, mobility, peripheral vision, etc.

Conclusion

The extent of the intervention to introduce additional controls will be determined by the gap existing between the current level of risk and the tolerable level for that risk.

The final decision to implement a specified control rests with senior management after quantifying the risk and having conducted a cost benefit analysis.

© 2009 Carl Marx