Emergency stop update Plant Assessor wide

Written by Paul Dean | August 2020

There have been a few questions about emergency stops of late.

As always such enquiry prompts the Plant Assessor Intellectual Property department to review the current situation. Whilst we have been providing the appropriate information from Australian Standard 4024:1604 Safety of Machinery – Design of Controls, Interlocks and Guarding – Emergency Stop there is an opportunity to improve the information provided.

There are two important components to the installation of emergency stops on machines –

Compliance with the physical attributes of the emergency stop as prescribed by the Australian standard i.e. colour, location, marking, actuation, resetting
The resulting effect on the machine post actuation i.e. What happens once the emergency stop is actuated, e.g. does the engine stop, does only part of the machine become isolated, how long does it take for danger to be removed etc.

Emergency stops have always posed a challenge for Plant Assessor as the installation of the device is specific to every machine, environment and use combination. The design of the Plant Assessor software does allow us to provide very specific information for individual makes, models and owners however it is impossible for us to know how an emergency stop device is set up for every machine. As a result today we provide information from the Australian Standard regarding all emergency stop installations as per point 1 above but not the actual detailed information regarding the specific installation for an individual machine.

The following additional information has now been incorporated into the Plant Assessor risk assessment process.

The emergency stop function shall –

Not impair the effectiveness of other safety functions
- Note: it can be necessary to ensure the continuing operation of auxiliary equipment such as steering & braking devices

Be so designed, that after actuation of the emergency stop device, hazardous movements and operations of the machine are stopped in an appropriate manner without creating additional hazards and without further intervention
- Note: appropriate manner can include optimal deceleration rate or necessity for predetermined shutdown sequence and so on
- A risk assessment must be conducted to confirm that no additional hazards have been created
- More than one emergency stop may be required

Be a complimentary protective measure and shall not be applied as a substitute for safeguarding measures and other functions or safety measures

Be designed so that a decision to activate the emergency stop device does not require the consideration of the resultant effects

Be designed so as to meet the requirements of AS4024:1604 Design of controls, interlocks and guarding – Emergency stop – Principles for design (ISO 13850:2017 (ED 3.0), MOD)

Additionally all operators should be familiar with the placement and actuation method of the emergency stop device as well as the resulting effect on the machine from actuation of the emergency stop device fitted to an individual machine.

As always if you have any questions regarding the information in this article please contact the friendly team at Plant Assessor.

Disclaimer: This information is intended to provide general information on the subject matter. This is not intended as legal or expert advice for your specific situation. You should seek professional advice before acting or relying on the content of this information.

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