I
Instrument (andheri)
In my opinion, an Emergency Stop should be accompanied by an audio / visual indication using perhaps a hooter and a beacon especially in a noisy shop floor environement or when large areas are involved. This is necessary so that the others
concerned are aware that some emergency exists. A normal operational stop does not require such indication.
Any emergency stop system should be tested at fixed intervals and this testing should be documented. After all Fire Drills are mandatory in many places? So why should Emergency Stops be
treated differently? Similarly, nobody would sound the fire alarm to announce the end of the day's work, although both may result in the employees leaving the building. So the normal operational stop and Emergency Stop functions should be segregated whenever practical.
Even in chemical plants, though the complete closing of an Emergency Shutdown Valve for testing may not be possible, it is still possible to design a system for 'Partial' Movement of the
valve to test the circuit.
Operating a switch once a month should not wear it out very much. I have known switches to malfunction just because they were not used.
Regards,
Sumeet
concerned are aware that some emergency exists. A normal operational stop does not require such indication.
Any emergency stop system should be tested at fixed intervals and this testing should be documented. After all Fire Drills are mandatory in many places? So why should Emergency Stops be
treated differently? Similarly, nobody would sound the fire alarm to announce the end of the day's work, although both may result in the employees leaving the building. So the normal operational stop and Emergency Stop functions should be segregated whenever practical.
Even in chemical plants, though the complete closing of an Emergency Shutdown Valve for testing may not be possible, it is still possible to design a system for 'Partial' Movement of the
valve to test the circuit.
Operating a switch once a month should not wear it out very much. I have known switches to malfunction just because they were not used.
Regards,
Sumeet