Developing a safe system of work

The difference between a Risk Assessment and a Safe System of Work

When a risk assessment is completed, developing a safe system of work might be one of the control measures required, but they are very different in use and structure. A safe system of work is a step-by-step procedure taking into account hazards, control measures and the provision of training together with the integration of personnel, equipment, materials and the environment with the ultimate aim of producing an acceptable level of safety.
Suppose the inside of a large underground storage tank is to be manually cleaned before being brought back into service.

risk assessment would need to consider things like the current methods of work, the previous contents of the tank (e.g. toxic, explosive), possible contact with residues, cleaning chemicals or hot cleaning liquids, the interaction between residues and cleaning chemicals, tools and equipment to be used, restricted physical dimensions, means of access and egress, means of isolating the vessel, and the likelihood of oxygen-deficient, explosive and/or toxic atmospheres.

Any safe system of work for the operation would be based on the identification of hazards and assessment of risks already completed. This would include risk controls such as a permit-to-work system, which would detail the precautions to be observed before entry to the tank and while the work is carried out. These precautions would likely include the tank’s ventilation, atmospheric monitoring, the isolation of services to the tank, the provision and use of personal protective equipment, the employment of competent personnel and arrangements for their supervision, and emergency procedures.

Analysing tasks, identifying hazards and assessing risks

A helpful framework for developing a safe system of work is to think about the ‘4 P’s’. These are: place, plant, people, procedures. For each of these, consider what is required at the following stages of the work: before, during and after.

That would give you a ‘grid’ of 12 sections that you can use to structure and broaden your thinking. See below for how this technique can be applied to working in confined spaces.


Introducing controls and formulating procedures

A simple safe system of work may be defined verbally or as a written procedure.

In all cases, the SSW should:

  • Consider the preparations and authorisations necessary before beginning work;
  • Ensure the job sequence is logically and clearly planned;
  • Specify safe methods for undertaking specific activities;
  • Specify safe means of access and egress if relevant; and
  • Consider the end-of-activity tasks such as dismantling and disposal.

Instruction and training in how to use the system

Training should be given in the system of work. This should include details of the hazards and risks involved, methods of work required, equipment to be used together with any pre-use inspections, PPE required. It should also cover what action to take if problems arise and any steps to be taken when the task is complete. Managers and supervisors will also need training to enable the effective implementation and ongoing monitoring of the SSW.

Monitoring the System

Once implemented, the safe system of work will require periodic monitoring to ensure the following:

  • The system is workable, and employees are comfortable following it;
  • The procedures as specified are being followed and are effective; and
  • Changes to the workplace or work practise that would necessitate a review and reiteration of the SSW are identified early.