Process and Plant Safety

Protection of humans and the environment from hazards posed by technical plants

Protection of humans and the environment from the hazards posed by technical plants – this is the main aim of Process and Plant Safety (PPS). Technology always comes with a certain amount of risk. What risks are acceptable? What protection measures are adequate for such hazards?

PPS has been in practice for over 100 years. Technologies have become better with time. Today, risks are avoided in a systematic manner. There exists internationally acceptable procedures for this purpose. Risk analysis are done and in doing so, adequate safety measures are derived. All the possible hazards need to be first identified and evaluated. This starts from identifying the hazardous material and hazardous chemical reactions. Such reactions are examined experimentally in laboratories. Pressure, temperature and flow parameters are monitored in a technical plant, in the event of malfunction.

PPS Protection of humans and the environment from hazards posed by technical plants

Some plants are designed in such a manner that there is no possibility of a hazard, even in the event of malfunction – these are the so called inherently safe plants. Sensors with very high reliability (Process Control Technologies) or safety valves and rupture disk devices (End-of-Pipe technologies) are however still applied in most technical plants. Basically, for a technical plant to be deemed as safe, multiple independent protection measures (Layer of Protection) have to be implemented.

Protection measures are selected proportionately based on the existing risk

In general the following is true: the larger the effects of a possible event in a technical plant, the higher the requirements in regard to protection measures. This principle is what is referred to as proportionality of risk.


Whenever a safety valve of a rupture device is activated, the hazardous material in the respective vessel must be collected and disposed safely. Apparatus such as separators, quenchers, absorbers etc. are installed downstream. Hazardous gases may only be released to the surroundings only when the allowable limits are not exceeded – this must be proven to the authorities.

Safety engineers in the PPS especially process the following tasks:

  • Hazard and risk analysis
  • Calculation of effects of events
  • Evaluation of hazardous materials and hazardous chemical reactions
  • Simulation of processes in pressurized apparatus in computation programs
  • Sizing of protection equipment
  • Design of containment equipment
  • Calculation of propagation of hazardous material in the environment
  • Recommendation of protection measures and evaluation of existing measures

The work of a safety engineer is as diverse as the related safety technologies.

Safety engineering as such comes with a high degree of responsibility when it comes to determining the right protection measures, even though most parameters applied in calculations are approximated with high uncertainties due to their nature. One must learn to counter these uncertainties.

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