Posted on Leave a comment

Read my lips the SAFETY E.S.D. button is not for LOTO it is for EMERGENCIES!

NO YOU CAN NOT HIT THE COMPANY RED DOOR BELL when you are doing LOTO operations it is for EMERGENCY USE only and it controls a lot more than one function on your site!  Oh by the way did your supervisor on site SHOW YOU THE POLICY and PROCEDURES for using this device?

When using emergency stop buttons and kill switches, are they designed in such a manner in which their role is more physical, such as interrupting a power supply (apparently in some of the models, like the one pictured, the button has to be turned before operation can resume), or are they just basic big red push buttons that are simply coded to wait until they’re pressed. The bottom line is that pressing the button should stop things in a safe way. Sometimes this means that they just cut power. Other times, when just cutting power is not the safe thing to do, they hook up to some type of controller that brings things to a halt in a safe way. What type of controller? Well, that depends on the machine and what is required (and is beyond the scope of this question).

According to government agencies and industry an emergency stop function is a function that is intended:

  • to avert arising or to reduce existing hazards to persons, damage to machinery or to work in progress;
  • to be initiated by a single human action when the normal stopping function is inadequate for this purpose.

Hazards for the purpose of this standard are those which may arise from:

  • functional irregularities (malfunctioning of the machinery, unacceptable properties of the processed material, human errors);
  • normal operation.

Simply put, an emergency stop function is a function that is initiated by a human action and is intended to shut down equipment in the case of an emergency.

Device Definition

The emergency stop device is a manual control device. It is the method of initiating the emergency stop function. The actuator of an emergency stop device is the component that is actuated by a person.

Examples of actuators include – mushroom-type push buttons, ropes, wires, etc.

For the purposes of this paper, however, any further references to an Emergency Stop will mean a mushroom-type push button. Emergency stop buttons are nothing more than a NC (normally closed) push button that has mechanical plastic or metal tabs and grooves internally such that when you push it (interrupting the circuit), it is held in that position until you twist it. They are designed to be large, hard to miss, and easy to push; qualities you want when you have that scary experience of having a powerful machine pulling your tie into the Rollers of Doom

 DO NOT take any unnecessary risks when shutting down utilities, mechanical equipment or technology.

DO NOT subject yourself to a hazardous environment (smoke, gas, electrical voltage, etc.)

DO NOT stand in water or any liquid when shutting down utilities, mechanical equipment or technology.




There are several reasons that a contact block could separate from an ESD button.

  1. Improper Installation – this could be due to any of the following examples:
  • Contact block/latch not re-installed after maintenance
  • Contact block mounting screws over/under tightened
  • Contact block/latch not completely “snapped-on”
  1. Physical damage
  2. Extreme vibration


Emergency stop devices are not a replacement for proper safeguarding or automatic safety devices. Rather, they should be used as a back-up measure. In addition, the activation of the emergency stop should not impair the effectiveness of other safety devices.

Your COMPANY specific steps needed to initiate safe shutdown of utilities, equipment and technology, it is recommended that digital pictures be taken of appropriate valves, switches and equipment to help the user locate and perform necessary actions. These pictures should be inserted as the page immediately following the guidelines for a specific item.

Plus after an emergency shutdown procedure has occurred, the utility, equipment or technology should only be reactivated or turned back on by a qualified technician or staff members who have been authorized by the person in charge of the facility or Incident Commander.

In plants or the oil industry they are:

An emergency shutdown system for a process control system includes an emergency shutdown (ESD) valve and an associated valve actuator. An emergency shutdown (ESD) controller provides output signals to the ESD valve in the event of a failure in the process control system. A solenoid valve responds to the ESD controller to vent the actuator to a fail state.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.