Shock tactics...
August 1st 2006

The control of static has always been important to industry in terms of reducing rejects and downtime. While quality remains a key consideration, companies are also recognising that eliminating the risk of static shock is important to avoid injury and to show due care and attention to staff welfare. Alan Chadwick, health and safety expert at Meech International, explains Static electricity is often considered as the hidden enemy of the health and safety professional, particularly in the manufacturing and processing industries. As an invisible force, it is often not identified as a problem until an incident occurs. However, the consequences may be serious for both the personnel involved and the company.

In recent years, we have seen an increase in the number of H&S officers seeking to ensure that their factories and cleanrooms are static-free. This is both to protect the well being of their workforce from the possibility of electric shocks and subsequent injuries and to ensure that the working environment is adequately protected against the risk of fire and explosion due to electrostatic discharge.

Originally, our main focus was to improve productivity and profitability in industry by reducing static charge build-up on processed materials machinery. This resulted in less waste, fewer rejects and reduced downtime. The control of static was seen very much as a quality problem. While the quality issue is still a major focus, we are now seeing health and safety concerns being discussed more openly. We have been working closely with companies and the health and safety departments to help reduce the hazard risk from static discharges and prevent operators from suffering static-related shocks.

Many people have experienced the uncomfortable feeling of an 'electric shock'. Activities as harmless as closing the car door, pushing a trolley around the supermarket or closing the dishwasher door can result in the discharge of more than 10 000 volts. However, as the current flows for such a short time, it is unlikely that any serious harm will occur.

In a factory environment, a machinery operator may receive a shock directly from the product he/she is working with or may become charged through induction. Induction occurs when a person stands in the electric field of a charged object, such as an operator in a converting plant adjacent to a plastic web during the unwinding and rewinding process. The charge builds up until the operator touches an earthed part of the machine and then discharges, resulting in a shock. It is unlikely to cause any serious harm but, if the shock is strong enough to cause a recoil reaction, accidents may occur as the operator collides with a colleague, with a machine frame or stumbles into the path of moving machinery.

In addition to avoiding injury to personnel and showing due care and attention to staff welfare, there are other factors to consider. When someone receives a shock, the machine has to be stopped to investigate the cause. This will result in downtime and lost production. Should the shock be strong enough for the recipient to require medical attention, then the machine cannot be restarted until it has been checked by health and safety experts. Production can be further affected if these shocks are occurring on a regular basis as people, intuitively, will work at a slower pace if they perceive there to be the risk of a shock. No one likes to experience pain and the constant threat of shocks will result in a dissatisfied and unhappy workforce. What's more, a company's failure to 'provide a safe working environment' may result in legal action.

In the past it has been difficult to control static. Special products such as conductive wristbands and floor mats are available but have proved impractical in areas where the workforce needs to move around. Meech provides a range of static control equipment that provides effective ionising solutions for the prevention of shocks. The company's range of ionising blowers is used widely throughout industry for this purpose, including benchtop, worksurface and overhead versions.

At one manufacturing site in Birmingham, for example, installation of a Meech ionising blower over a workstation has resulted in a 50% increase in productivity. Employees are working harder and faster and downtime has reduced as there is no longer the threat of shocks. It's a win-win situation for both the company and its employees.

There are other health and safety aspects to be considered, including the increased risk of fire or explosion, especially in processes using flammable liquids. More sophisticated control/antistatic solutions are required such as those provided by the use of a Pulsed dc and Ex (explosion-proof) system.

Meech International believes it can supply the best possible advice to suit all scenarios.

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