Baking&Snack - November 2011 - 62

EMPLOYEE SAFETY

Even though OEMs design their equipment with safety in mind, they can’t always catch every little thing, according to Rick Rodarte, director of engineering, Stewart Systems, Inc., Plano, TX. Therefore, when Stewart Systems delivers a piece of equipment, he noted, the bakery’s safety team will ▼ This e-stop, or emergency stop, button is used to halt equipment to help prevent accidents.
READING BAKERY SYSTEMS

generally review it and include its own ideas about safety features that may need revision. “You can look at this as a burden because you might have to redo some things, but it actually only makes the equipment better and more safe,” Mr. Rodarte said. “I’m never opposed to hearing other people’s opinions on how we do things because you have got to protect operators.” In addition to building equipment to meet OSHA standards, Stewart Systems reviews more stringent requirements from Europe that would allow the equipment manufacturer to use the CE mark, according to Mr. Rodarte. “In Europe, they go over the top with safety, but I think a lot of the things they require are pretty nice,” he said. “They really push you

to the limit on safety, but you can see a difference.” CE stands for Conformité Européenne, or “European Conformity,” and this designation is required for all systems sold in the European Economic Area, which includes the 27 member states of the EU as well as European Free Trade Association countries. To meet these stricter standards, Mr. Rodarte said, Stewart Systems includes lockout key systems on ovens and fencing around the entire front of ovens installed in Europe. These measures go above and beyond any US safety requirements. Designing equipment to these standards can be cumbersome, he said. “One of the challenges when you are doing anything with safety is, Are you allowing enough access

Flipping the Switch on Safety
Although Rick Rodarte, director of engineering, Stewart Systems, Inc., Plano, TX, said it’s difficult to say that any new or cutting-edge safety systems have been introduced in recent years, he pointed out that companies are continually coming out with devices that work in parallel with machines’ control systems, and now it’s possible to integrate safety devices and relays with PLCs. “For a long time, safety devices had to be hardwired, and you couldn’t go through any kind of electronic system or a PLC, because if a PLC lost power, the machine was considered unsafe,” he said. Now, safety relays are integrated into PLCs, and plants can put them online either through a local Ethernet or the Internet. “A plant can have a master system to monitor,” Mr. Rodarte said. “If a piece of equipment goes down, they can determine whether it was a safety switch or a motor fault. They can categorize incidents as they monitor them for efficiency or for safety numbers in their working organization.” The fact that processors cannot defeat safety switches as easily as they once could represents the most important change in safety systems, according to Mike Hall, director of engineering, Shaffer, A Bundy Baking Solution, Urbana, OH. Defeating safety switches wasn’t just an issue in the baking industry but in all types of manufacturing plants; operators would commonly defeat safety switches to keep machines operating as they liked. They would use electrical tape or paper clips to defeat switches, Mr. Hall said, adding that he has seen many different methods employed. “Now, they cannot do that, or at least it’s a lot more difficult to do,” he said. It’s more difficult because manufacturers have come out with new switches to meet the latest safety standards. “The technology for the switches has changed, so now you have true safety-rated switches,” Mr. Hall said. Safety switches can provide a key line of defense to protect employees. For example, Stewart Systems uses safety switches on its oven doors that will set off an alarm and shut down the oven should someone open a door. “It goes into full exhaust,” Mr. Rodarte said. “You’re trying to pull heat out of there as much as you can because you can’t have someone walking into a 400°F environment.” Approved safety devices are required when integrating electrical hardware into the safety circuit, according to Travis Getz, director of engineering at Reading Bakery Systems, Robesonia, PA. “The three categories of safety devices are optic, switching and stopping,” he said. “A combination of all three may be required on some machines.” Optic safety devices are also referred to as light curtains, which will cause a piece of equipment to automatically shut down if tripped. Switching devices such as keyed, magnetic or hinged interlocks and limit or RFID switches are used when a device switches states, according to Mr. Getz. “We use all of these devices on our equipment when interlocking guard doors and access points,” he said. “The device is determined by the type of guarding required. Noncontact switches, primarily RFID, have become more popular recenlty due to the ease of integration.”

BAKING & SNACK / November 2011

www.bakingbusiness.com

http://www.bakingbusiness.com

Baking&Snack - November 2011

Table of Contents for the Digital Edition of Baking&Snack - November 2011