Analysis of hazards and risks

• Pages: 23-25

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5. Analysis of hazards and risks

5.1. General

5.1.1. Hazard analyses should be carried out primarily by works management,

but the same technique may also be applied to the evaluation of safety systems by

the competent authorities.

5.1.2. To analyse the safety of a major hazard installation as well as its

potential hazards, a hazard analysis should be carried out covering the following

areas:

(a) which toxic, reactive, explosive or flammable substances in the installation

constitute a major hazard;

(b) which failures or errors could cause abnormal conditions leading to a major

accident;

(c) the consequences of a major accident for the workers, people living or working

outside the installation, or the environment;

(d) prevention measures for accidents;

(e) mitigation of the consequences of an accident.

5.1.3. The hazard analysis should follow a formalised method to ensure

reasonable completeness and comparability.

5.2. Preliminary hazard analysis (PHA)

5.2.1. As a first step in hazard analysis, a PHA should be carried out.

5.2.2. A PHA should be used to identify types of potential accident in the

installation, such as toxic release, fire, explosion or release of flammable material,

and to check the fundamental elements of the safety system.

5.2.3. The PHA should be summarised in documentation covering, for each

accident considered, the relevant component (storage vessel, reaction vessel, etc.),

the events initiating the accident and the corresponding safety devices (safety

valves, pressure gauges, temperature gauges, etc.).

5.2.4. The results of a PHA should indicate which units or procedures within

the installation require further and more detailed examination and which are of less

significance from a major hazard point of view.