USED RISK ANALYSIS METHOD
Inductive analysis method (Modified Zürich Hazard Analysis, MZHA) of the relative quantification. In other words the risk is assessed by comparative consideration. This method is based on the US Military standard 882, that corresponds to the System-Safety-Concept, which was developed in the 50’s for the aviation and space industry in the USA.
Risk analysis with a semi quantitative character has been in use for a long time and worked satisfactory. An example of such risk assessments, which are based on technical expert knowledge and experiences of many years, is the hazard area classification for explosion protection.
Once all the hazards (e.g., the 13 ignition sources) of each plant component have been identified, an estimation of the impact of the possible harm which can arise and the probability of occurrence of each hazard has to be made in order to rank the risks. The impact is ranked in four categories ranging from "catastrophic" to "insignificant", while the probability of an event occurring is expressed in six stages from “frequent” to “practically impossible”. A risk-profile grid is drawn up in which the safety objective, e.g., the acceptable risk to be established by the risk analysis team in accordance with its management (or in line with the expected safety level) can be illustrated by a stepped line, which is equal to the SAFETY OBJECTIVE.
Used Standards, Technical Reports:
EN-ISO-14121-1: Safety of machinery – Risk Assessment; Part 1: Principles
EN 1127-1: Explosive atmospheres – Explosion prevention and protection - Part 1: Basic concepts and methodology
RASE-Project, Explosive Atmosphere: Risk Assessment of Unit Operations and Equipment (SMT4-CT97-2169)
ESCIS /Expert Commission
for Safety in the Swiss Chemical Industry) Introduction to the Risk
Analysis – Approaches and Methods, Booklet 4