Difference Process shutdown (PSD) and Emergency Shutdown (ESD)

ESDV ACTUATOR

PSDV ACTUATOR

PSD is defined as the automatic isolation and the activation of all part of a process. During a PSD the process remain pressurized, Basically PSD consist of field mounted sensors. Valves and trip relays, a system logic unit for processing of incoming signals, alarm and MHI units. The system is able to process all input signals and activating output in accordance with the applicable cause and effect matrix chart

Typical action from PSD systems are:

1.       Shutdown the whole process

2.       Shutdown part of the process

3.       Depressurize/Blow down parts of the process

The emergency shutdown (ESD) is shutdown to minimize the consequences during emergency. ESD can be automatically initiated by load shedding functions or manually by the operator through push button on the panel. ESD will shutdown an isolate all designated process related equipment, including inlet and outlet ESD valves. Depends on each project some plant will allow the power generation, utilities and fuel gas system keep running during this condition.

ITEMS SAFETY INSPECTION CHECK FOR GAS TESTING

1. Are personnel trained in the use of gas detector equipment?
2.  Is there a master list on site of the certified authorized gas testers?
3. Are the portable gas detectors kept in a secure location when not in use?
4. Are the portable gas detectors uniquely identified and is the latest calibration date displayed?
5. Is maintenance work on gas detector carried out only by qualified personnel?
6.  Are the portable gas detectors tested prior to issue as per the pre-issue checklist?
7. Has a gas test been completed before any Hot Work commences in classified area?

ITEMS SAFETY INSPECTION CHECK FOR IONIZING RADIATION

1.  Are radioactive isotopes used on site? If so are personnel aware of the dangers?
2.  Are all the required personnel carrying dosimeters?
3.  Is the storage area regularly surveyed and the results below 7.5 uSv /hr.
4.  Is the labeling of the storage area sufficient?
5.  Is the labeling of the source containers clear?
6.  Are sufficient barriers/warnings/flashing lights in place prior to exposing a source?

ITEMS SAFETY INSPECTION CHECK FOR WORKSHOP

1. Is the workshop outside a hazardous area?
2. Does the electrical installations look satisfactory?
3. Are there any temporary electrical installations?
4. Are there 3 means of cutting off the electrical supply to any machine?
5. Is the local stop/emergency button well labelled & in red?
6. Is any "dead man" handle being bypassed?
7. Are all moving parts adequately guarded?

PIPING & INSTRUMENTATION DIAGRAM SYMBOLS

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