PLANT MACHINERY & SITE SAFETY SETTING THE STANDARD
Paul Taylor, Head of Industrial Products (UK) at TÜV SÜD, a global product testing and certification organisation explains the changes behind the BS EN ISO 14118: 2018 standard regarding unexpected machinery start-ups.
As industry innovation has seen greater levels of machinery automation, the probability of hazardous occurrences caused by unexpected start-ups and the resulting potential injuries, or lucky escapes, has grown.
After more than 20 years, BS EN ISO 14118:2018 superseded BS EN 1037:1995+A1:2008. It states what procedures should be followed to ensure that a dangerous area of a machine is entered safely. The overriding guiding principle is to ensure that a machine is in a state of zero energy, ensuring that it is isolated from the power source and that latent energy within the machine has been dissipated.
There are quite a few changes to the standard, but below are some of the key highlights to ensure that you are compliant.
Section 4 (General measures to prevent unexpected start-up) introduced a new element, specifically requiring that a risk assessment is performed and that procedures to prevent unexpected start-up are described in the instruction handbook and/or warnings on the machine.
Sub-section 4.4 (Signalling and warning -delayed start) was also new. It states that an audible and/ or visible warning signal and delayed start shall be provided, if required by the risk assessment, in order to alert a person to the impending start-up, with the delayed start giving them enough time to leave the danger zone.
Section 5 was renamed ‘Isolation and energy dissipation’, and a new sub-section (5.1) now covers unexpected start-up prevention when power supplies are restored. Sub-section 5.2.2 also introduced two new elements when considering the location and number of power supply isolation devices, which must be present to ensure a reliable disconnection or separation from the energy source:
• Note 2 - where it is necessary to have access to individual parts of large machinery, a separate additional isolation device is required.
• Note 3 - the location of the isolating device, must either be at the place of the intervention or along the access route.
Locking isolation devices is essential as they stop anyone being tempted to override safety measures. Both the new and old standard required that: “The isolation devices shall be capable of being locked or otherwise secured in the ‘“isolated” position,’ but the new standard goes into much more detail. It also
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makes a further suggestion about a suitable locking device, in the form of personal keys, which can be released from a trapped key interlocking device and retained by a person, so that no one else outside the machine can accidentally start it up.
Devices for stored-energy dissipation or restraint must now be provided where stored energy can give rise to a hazard. The old standard simply required that the necessary procedures are described in the instruction handbook, or in warnings on the machine itself. However, the newer standard adds the requirement that (section 5.4.1.4): “The machine shall not be able to be started with dissipation devices activated or restraint devices in place if this generates new hazards.”
When considering measures to prevent unintended actuation of manual start controls, the new standard adds some additional detail (section 6.2.1): “Where a control device is designed and constructed to perform several different actions, namely, where there is no one-to-one correspondence, the action to be performed shall be clearly displayed and subject to confirmation, where necessary.” This is intended to ensure a positive understanding of any action taken by that control, and where this may not be clear, that it is displayed and requires confirmation before the action can take place.
Section 6.3 of the new standard covers measures to maintain stop commands, and a key update here is the addition of a note which specifies that the emergency stop function cannot be considered as a measure of prevention of unexpected start-up. This means that the emergency function must be an addition to any systems put in place to prevent unintended start-up when people enter a dangerous area of the machine, essentially ensuring a ‘belt and braces’ approach to machine safety.
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