MAINTENANCE - 21.06.2018

Bypassing safety devices

What happened?

In October 2016 an employee of a precast concrete products manufacturer, CPM Group Ltd (CPM), was carrying out maintenance work in an area protected by fencing. He was only able to access the area using a special safety key, and this arrangement should have ensured that the dangerous parts of the machine were isolated from power sources. However, while he was in the danger zone a conveyor system began to move unexpectedly and he was fatally crushed. In 2018 the HSE brought a prosecution against CPM. The company pleaded guilty to breaching the Health and Safety at Work etc. Act 1974 . It received a fine of £660,000 with £14,564 in costs.

Where did it go wrong?

The HSE investigation confirmed that the enclosure was normally kept locked, but the safety measures failed because of shortcuts staff were able to take.

The security installation the company used is known as a “captive key” system. A key has to be in place for the machine to fully function, and when it is removed the equipment is put into a safe mode. This simple concept works well as a method to control access to safety-critical areas, but only if there are no spare keys in circulation. In this case the employee had used a spare key to open the gate, leaving the machine fully functional. The HSE discovered that spare keys were readily available and appeared to be regularly used.

Tip 1. If you have implemented access restrictions for safety reasons, make sure that they work in practice. Key copying is a common cause of accidents. Keep spare keys under the strict control of one senior manager.

Tip 2. Inform staff that spare keys must not be cut and that key control procedures will be followed at all times. Treat any contravention as a disciplinary offence.

Permits

Another HSE finding was that the company had a permit to work system in place. Although the permit document had been completed for this job, the supervisor had not followed through to ensure that what was written was fully applied.

The document detailed how the work should be completed safely, including the shutting off and locking of the machine’s power supply. However, the work went unsupervised, with the control measures shown on the permit to ensure the machinery was isolated and safe not being checked.

Note. When issuing permits to work, there is a common misconception that this can be done successfully as a desktop exercise. However, permits are generally only used when the work presents a serious risk of harm, so it’s worth getting off your chair.

Tip. The supervisor should be on site prior to the start of the job to ensure that the actions listed on the permit document have been carried out. Only then should it be signed off (see The next step ).

For a permit to work policy, visit http://tipsandadvice-healthandsafety.co.uk/download (HS 16.20.04).