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Lockout tagout – LOTO for machine safety


LOTO Lockout tagout to stay safe

With today's highly connected world and the approach of introducing smart technology to all things industrial, it's sometimes easy to overlook the simplest of solutions. Lockout tagout is a highly effective solution to delivering machine and user safety. 

The need for visual and physical safety to prevent serious harm to employees and assets is still as true today as it ever was. With the advent of the Industry 4.0 and IIoT ushering in new capabilities for networked solutions, the actual safety aspect may still rest with tried, tested and required procedures to be followed.

The lockout tagout (LOTO) approach is still the most widely deployed and simplest solution. This is where electrical, hydraulic, pneumatic, thermal or mechanical devices are disabled physically or locked into a non-live condition with some form of locking mechanisms, such as a padlock or hasp. Highly visible tags can also be applied to enlighten operators to the lock out status.

However, lock and tag is only part the story, it can be said the general nature of some of the standards and the potential effects of a drawn-out downtime caused by what is sometimes described as an excessively cautious approach, has led business owners to explore ‘workarounds’ which, although still safe, push a little against the basic essence of many safety standards.

BS 7671:2008 states: “Every employer shall ensure that where appropriate, work equipment is provided with a suitable means to isolate it from all its sources of energy. Every employer shall take appropriate measures to ensure that reconnection of any energy source to work equipment does not expose any person using the equipment to any risk to their health or safety”. This is relevant for the UK. EU country standards exist too in the EU, and at an umbrella level the advice contained in EU Guidelines 89/655 (Paragraph 2.14) mentions that: “Every piece of equipment must be fitted with clearly visible devices with which it can be separated from every energy source”. This is complemented by the EN 1037 norm, which covers equipment safety, energy isolation and power dissipation, while European directive CEE 89/655 outlines the minimum regulations for the safety and protection of employees when servicing industrial equipment.

Common with a broad range of standards and guidance notes, there is a degree of interpretation and workarounds may be made in certain cases. (In general, it’s best practice to follow standards and not interpret them). Workarounds must be backed by a stringent due diligence and robust risk assessment process which should stand up to scrutiny. Best practice for LOTO demands precise thinking of all aspects of the operation of a machine and, of course, the potential negative effects of incorrect actions.

A structured, stepped approach to defining LOTO procedures is considered best practice by many safety suppliers. This can be broken down as follows;

  • Explanation of a policy that states the needs and reasoning behind the LOTO application.
  • Identification of the assets and components, especially those used to control the energy requiring isolating to which the policy applies. This will include switches, isolators, valves, and heat sources.
  • Application of the correct tools and equipment to achieve the lock out.
  • The creation of a procedure with the resulting instructions together with training on how this procedure is followed. This would be required per machine or product.

At this stage, those directly and indirectly affected by the application of the lockout are made aware of the procedure and its implications on their day-to-day roles.

There is an abundance of suppliers in terms of basic hardware and users are spoilt for choice when it comes to the essentials, such as hasps, padlocks and tags. However more specialist applications will require specific devices, and it’s likely that bespoke components will be essential in this instance. Many electrical and automation suppliers such as ABB and Siemens offer dedicated safety hardware to complement their ranges. SMC similarly offers effective products for LOTO within the pneumatic arena, such as lockable isolation valves, while RS offers starter kits for valve lockout within its RS Pro range.

This provision of suitable hardware is backed up by consulting services in many instances too, with vendors offering LOTO audits and help to formulate robust LOTO policies. And it is this support that delivers additional peace of mind and enhanced legal conformity (with the usual provisos), backed up by effective due diligence practices should the worst happen.

We mentioned that safety is getting smart and you may think that the provision of padlocks and tags is not exactly fertile ground for an Industry 4.0 approach, but this is actually far from the case. Many LOTO procedures can be managed, defined and delivered using tablets and hand-held devices, with the added benefit of delivering completely up-to-date procedures – served from a central source, as opposed to an out-of-date printed policy folder. Historical data can also be gleaned from these connected devices, where LOTO applications can be monitored, time-stamped and recorded, and then used to define or identify shift or seasonal breakdowns.

LOTO is an incredibly simple and effective approach to what is now a complicated, sometimes over-generalised, very heavily legislated issue. As part of an overall holistic safety regimen, the ultimate aim should be to prevent injuries, damage and errors by providing operators and maintenance engineers with a safe working environment. There will always be situations where it is overkill to isolate an entire machine or line, but as standards and technology evolve this will be, and indeed has been, catered for to a certain extent. In the short term – and for the foreseeable future – a big, brightly coloured padlock and tag is the best possible solution, especially in light of operator errors making up such a high proportion of industrial accidents.

The table below highlights the individual elements to build a working LOTO application. Taking the SMC FRL assembly and adding the relevant shut-off valve and bracket give a LOTO-working solution. Please note that a padlock would also be required to complete the application, such as (862-5155) or similar. 


FRL assembly


Shut off Valve


















































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April 25, 2018 07:10

Interesting stuff Greig, on the subject of locking down those isolation points, I've noticed on my travels this company (amongst others), this company produces Bluetooth controlled padlocks and locks. Being cloud-based too, this kind of functionality could be utilised within a LOTO system, showing exactly when and who applied the lock-down digitally.

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