Safety systems up to date?

Newer machine guarding requirements emphasize reliability and continuous functioning. PHOTO: THINKSTOCK

Guarding keeps workers safe from moving machinery, yet as standards and systems changed, many plants lagged in the maintenance and upgrading of their safety systems.

It’s the employer’s legal responsibility to make every reasonable effort to ensure machine guards are in place, they function as intended and they’re used according to established procedures.

Machine guarding requirements are more stringent than they were in the past. They focus on preventing access to hazards through elimination, design and engineered controls. There’s much less reliance on workers’ common sense and more emphasis on reliability and continuous functioning. Changes of note to systems and standards include:

• Processes for the evaluation of risks to the worker are detailed and alternate options for solutions are outlined and ranked in CSA Standard Z432-04 – Safeguarding of Machinery.
• Standards for electrical control integrity/reliability such as ISO 13849-1 and EN 62061 have been revised to lead to the type of electrical control system likely to deal safely with the level of risk identified.
• Safety rated control components are more available, reliable, adaptable and affordable.

There are many innovative ways plants have successfully updated their machine guarding without affecting productivity.
A manufacturer of high voltage instrument transformers, bushings and coil products was challenged by limited space in its Toronto facility. Reactors were being tested at high voltages in an area frequently used as an aisle. Procedural measures were taken but the residual risk was still considered unacceptable.

The plant owner considered using a physical barrier to protect staff but that would have limited and interfered with the movement of product within and near the testing area. That would have impeded production.

The speed and operation of lift trucks operating in the vicinity, the length of the tow motor forks, foot traffic, the height and size of the product and the speed at which the hazard could be stopped all had to be considered.

The solution involved a combination of light curtains, warning lights and markings. Physical barriers were used to provide the needed protection and to avoid accidental disruption to the testing. Production was not affected.

At a Mississauga, Ont. plant that produced roll-formed steel products, rollout tables were posing a safety problem. There was a shear hazard created between material and the rollers that created a risk to the operator who had to quickly remove lengths of thin steel from the conveyor.

The company solved the problem with sloped sheet metal inserts that eliminated the shear hazard and allowed the operator to get hands under the panels. The safety issue was addressed without reducing the speed products were removed from the roll.

A Toronto packaging plant built in the 1970s had made various improvements over the years, but its equipment needed safety upgrades.

Machine drawings and electrical diagrams were not available, and areas on the line required different approaches to improve safety. One area needing attention was the coating application section of the packaging line. Since orders requiring the coating were difficult to predict, meeting production targets throughout the upgrading was essential.

There were a number of components that presented risks to workers. Conveyor chains and other moving parts weren’t guarded sufficiently to reduce risk of injury, and safeguards for workers that required frequent access to the machine weren’t adequate.

Necessary action
Upgrades included access doors that opened in two parts. This allowed access through the top to prod sticky product but not through the bottom (where there were hazards).

New safety certified electrical controls were also installed to remove power from the process controls used to start machinery that could be hazardous when operators needed access to certain areas.

The main safety panel was pre-assembled off site and electrical installation was complete in three days.

Upgrades were organized and timed around the plant’s production schedule allowing the machine to be used up to the first day of the install. This approach also got the plant back into production by the afternoon of the third day.

Careful consideration of workflow and changeovers went into the design of the mechanical guarding so it wouldn’t impede the efficiency of the process once changes were made.

Production requirements were met and productivity was not hindered during the installation of the safety upgrades – important deliverables for all the plant projects cited.

Employee safety must always be a plant’s first priority. Overlooking procedural shortcuts and hazards that “have always been there” can result in serious injury or death. Upgrading safety systems seems daunting, but done with the right team and a bit of innovative thinking, they can be done while addressing all the key business priorities.

Ralph Balbaa is president of HITE Engineering, a Mississauga, Ont.-based consulting firm specializing in industrial and construction safety. He has more than 40 years of engineering experience and is a former Ontario Ministry of Labour consultant.

This article appears in the September 2014 issue of PLANT.

Comments? E-mail jterrett@plant.ca.