7.1 Introduction

The Management Regulations 1992 resulted in a variety of risk assessment techniques being developed, many of which involved the use of risk rating or quantitative assessment techniques. However, the ACOPs accompanying both the 1992 and the 1999 Regulations have emphasised that the degree of sophistication of the risk assessment should be determined by the level of risk arising from the work activity. The 1999 ACOP provides further detail on this point:

Small businesses presenting few or simple hazards:

• risk assessment can be a very straightforward process based on informal judgement and reference to appropriate guidance .

Intermediate cases:

• risk assessment will need to be more sophisticated;

• specialised advice may be required in some cases; and

• some specialist analytical techniques may be required, e.g. measuring air quality and assessing its impact.

Large and hazardous sites:

• require the most developed and sophisticated risk assessments, particularly where there are complex or novel processes;

• for sites using or storing bulk hazardous substances, large-scale mineral extraction or nuclear plant, risk assessment will be a significant part of the safety case or report and may incorporate such techniques as quantified risk assessment; and

• the COMAH 1999 and other statutory requirements (e.g. in the nuclear industry) may require more specific and detailed assessment techniques.

7.2 Risk rating matrices

Many different risk rating matrices have been developed as an aid to the risk assessment process. Several examples are put forward below whilst the pros and cons of this type of approach...