BASIS OF SAFETY REGARDING BONDING MIXING UNIT
Process operations where an explosion hazard may exist require a basis of safety to
ensure that the hazard is being controlled such that the overall risk is within an acceptable
range. A basis of safety usually comprises of a primary and secondary basis of safety. The
primary is usually based on prevention methods reducing likelihood of an explosion. The
secondary is based on protection methods, mitigating the consequences of an explosion.
In conjunction, risk is clearly reduced. Clearly, avoidance of an explosion is desirable as
even with well designed protection systems an inherent reliability is present, so they may
not work when required.
The general principle is to try and achieve the highest ‘reasonably practical’ level of risk
reduction. This essentially means that expenditure on risk reduction measures is
reasonably expected up to the point where further risk reduction becomes disproportionate
to the level of expenditure. This principle should be applied when considering the basis of
safety for this process.