PPS at the CSE
Process and Plant Safety
How safe are our technical plants – how safe can they be?
Protecting people and the environment from the dangers posed by technical systems – that is what process and plant safety (PPS) is all about. There is no such thing as technology without risks. But which risks are permissible? How do you protect yourself from hazards?
PPS is the protection of people and the environment from hazards caused by technical facilities.
PPS has been around for over 100 years. The techniques have become more and more sophisticated. Today, a very systematic approach is taken to avert dangers. There are internationally recognised procedures. Risk analyses are carried out and protective measures are derived from them. First, all possible hazards must be determined and evaluated. This starts with hazardous substances and dangerous chemical reactions. These are usually investigated experimentally in laboratories. Pressures, temperatures and flows are monitored in case there is a malfunction in the operation.
Some plants are built so safely that there is no danger even in the event of a malfunction. Such systems are inherently safe. However, in most technical systems, additional sensors with a very high reliability must be installed (PCE protective measures) or safety valves or bursting discs (end-of-pipe technology) must be installed to protect the system. In principle, several independent protective measures must be selected (layer-of-protection concept) so that a technical system is considered safe.
Risk proportionality must be taken into account when selecting protective measures.
Basically, the greater the effects of a possible event in a technical plant can be, the higher the requirements for the protective measures. This approach is called risk proportionality.
If a safety valve or rupture disc activates, the hazardous substances must be safely collected and then disposed of. Separators, quenches, immersions, etc. are installed downstream as technical apparatus. Hazardous gases may only be discharged into the environment if the permissible limit values are not exceeded. This must be proven.
It takes a great deal of responsibility to determine the right protective measures, even if many parameters can only be estimated with uncertainty in calculations. One must learn to deal with the uncertainties.
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The work of a safety technician is as wide-ranging as the technology itself.
PPS safety engineers are responsible for:
- Hazard and risk analyses
- the calculation of impacts in the case of events
- they must assess hazardous substances and dangerous chemical reactions
- simulate the processes in pressurised equipment with computer programs
- Design safety devices
- Dimension restraint devices
- calculate the dispersion of hazardous substances in the environment
- Specify protective measures or assess existing ones