ABSTRACT
A safety analysis in accordance with the German Ordinance on Industrial Accidents was produced for an existing plant where liquid natural gas (LNG) can be liquified, stored and revaporised to cover peak demand. The aim is to prove that the necessary technical and organisational measures to prevent accidents and to limit the consequences of an accident have been taken. A major component of this is the analysis of potential hazard sources. Systematic methods have to be employed here.
Three different methods are presented in detail here. These are the methods which, to varying degrees, are used in Germany when it comes to producing safety analyses:
HAZOP/PAAG Method
Failure Mode and Effect Analysis
Fault Tree Analysis
840The HAZOP/PAAG Method, an expensive procedure, is being ever increasingly successfully employed in the search for hazard sources in the operation of chemical and industrial processing plants.
Failure Mode and Effect Analysis is less expensive and is therefore employed more often. To use Fault Tree Analysis, knowledge of failure rates/probabilities is required – information which the chemical plants do not, as a rule, have at hand, due to the operational conditions particular to that industry. This method is therefore seldom used in this technical field and employed only when very detailed studies are undertaken.
Using the three methods as examples on one part of the natural gas storage plant, practical hints for carrying out the methods are given and suggestions made about which additional requirements need to be taken into account. The same hazard sources were uncovered by each of the three methods, leading to concrete alterations in the plant. This confirms the effectiveness of the methods.
