Plant Safety:

Selection and classification of safety devices and safety Instrumented systems

Selection and assessment of safety equipment

For the protection of persons, of the environment and of plants the risks of every system need to be assessed and appropriate safety systems installed. It is, in many cases, not possible to achieve a system which is safe in itself (inherent safety). Complementary safety measures are needed for a required minimum safety level. These can include systems acting purely mechanically such as e.g. pressure relief devices, but also safety instrument functions which lead to a safe state of the plant on demand.

The methods for selecting and assessing these measures range from qualitative classification through risk graphs to semi-quantitative assessment in the Layer of Protection Analysis (LOPA) and fully quantitative methods (quantitative event tree). It is advisable for all these methods to consider the entire system first in a systematic risk analysis (e.g. HAZOP, check lists).

For the process industry, the quality of a safety instrumented function shall be determined acc. to IEC 61511. This includes determination of the required SIL as well as verification of the required PFD- and HFT-values.

Requirements of safety systems

minimisation of the risk of plants with major danger potential
reliable prevention of dangers for persons, the environment and the equipment itself
achievement of a safety level of the entire plant acceptable to the public and to authorities
high availability of the plant due to avoidance of malfunctions of safety systems

Scope of services

selection of methods according to the specific situation determination of the required safety integrity level
input of know-how of international regulations regarding the required and recommended safety equipment
assessment of existing safety systems
moderation of the discussions and preparing of the documentation.

Contact
Dr. Reinhard Preiss
Krugerstrasse 16
1015 Vienna, Austria
Tel.: +43/1/514 07 ext. 6136
Mobile: +43/664/827 18 27
Fax: +43/1/514 07-6145
e-mail: prr@tuv.at