Five essential requirements for emergency stop devices
August 15, 2022
To protect employees and prevent workplace injuries, emergency stops are a must-have in any safety system.
To protect employees and prevent workplace injuries, emergency stops are a must-have in any safety system.
The expert team at Omron has identified five essential requirements you need when implementing E-stop devices:
1. The E-stop must have ‘positive operation’
Emergency stops must be designed so that when activated, dangerous movements and operations of the machine will be stopped as quickly as possible without creating additional hazards. If they aren’t activated, the machine must stay running by default. This is what’s meant by “positive operation.”
2. The E-stop function must be available and operational at all times
At every operator station, there must be an emergency stop ready to be activated whenever necessary. The effects of an E-stop – namely, the ceasing of hazardous machine motion – must be maintained until the device can be manually reset according to strict safety requirements. This prevents machinery from starting up prematurely during an investigation.
3. There can’t be a padlock on the E-stop
Having a padlock on the emergency stop device gives the impression of lockout/tagout (LOTO), which is a terrible application for an E-stop. Requirements for lockout stipulate that the hazardous energy sources must be physically isolated or blocked, and control systems that include interlocks and emergency stops are unable to meet these requirements in full.
4. The E-stop shouldn’t stand in for other necessary safety measures
Key safeguarding measures and functions such as light curtains, interlock devices and comprehensive safety training for operators must not be overlooked simply because an emergency stop is in place. These measures are just as important and should always be part of the risk reduction strategy for a machine.
5. The E-stop should ideally be activated twice a year
Assuming there’s no need to stop hazardous motion over a 12-month period, the emergency stop should only be activated twice during this period for manual testing.
Some manufacturers set up a device so that operators use the E-stop for routine machine shutdowns, but this is a standards violation and will lead to the early breakdown of the device.
Want to learn more about Omron E-stops?
Check out our latest product range - Click here for AU and click here for NZ.