Can your guard rail take the hit?

They may not be sexy, but they are a vital part of your safety plan.

03/21/2012


Yellow tape is not an effective barrier to vehicle accidents on the plant floor. Courtesy: Wildeck Inc.Guard rail is one of those facility components that typically are not top of mind with companies until it’s too late. Soft federal guidelines for guard rail use have helped contribute to its low awareness within facilities, and have placed the onus for use on individual companies to implement.

When used properly, guard rail can effectively protect equipment, assets, and personnel in and around a facility. The key is to identify areas in need of guard rail, correctly specify it for the application, and take action.

Why guard rail?

While industrial guard rail protects machinery and provides a safe and efficient work environment, its most important role is protecting people. Forklifts, tugger automatic guided vehicles, and other material handling vehicles are commonplace in manufacturing facilities and often operate in close proximity to employees. Sometimes their paths do cross—with deadly results. According to OSHA, there are about 85 fatal forklift accidents per year in the U.S., 34,900 accidents that result in serious injury, and about 61,800 accidents that are classified as nonserious. Additionally, slightly less than half of the estimated 85 annual fatal forklift accidents occur in manufacturing facilities; of that about 10% involve people getting struck or run over by a forklift.

How do forklift accidents happen? OSHA says that most accidents could have been prevented with better operator training. Still, it’s easy to see how an accident can occur. Many manufacturing facilities have tight lanes for forklifts to drive. If a turn isn’t executed properly, the wheels or forks could sway into a designated safe area occupied by employees or equipment. Place an inexperienced driver behind a forklift and the risks increase. Well-positioned guard rail can help reduce the chance of accidents by preventing forklifts and other vehicles from straying into dangerous or off-limits areas.

While there are OSHA guidelines regulating the use of hand rail and other guarding devices in facilities for structures such as stairs, mezzanines, temporary manhole covers, etc., there is no direct guidance for the use of guard rail around machinery or designated vehicle travel paths. As such, many facilities simply mark the floor for off-limit areas, travel paths, and pedestrian walkways with yellow-striped tape—which provides absolutely no protection against vehicle impact.

Differences in guard rail

Although it may look similar in appearance, not all guard rail is made the same. Many manufacturers build guard rail to have an impact rating of 10,000 lbs at 4 mph. An average forklift with a load generally weighs between 8,000 lbs and 10,000 lbs. A 10,000-lb impact rating means a forklift should be prevented from driving through the guard rail at a speed of 4 mph or less. The goal of industrial guard rail is to maintain its integrity and deflect an impact. In contrast, highway guard rail is designed to absorb and disperse an impact, which is why at an accident scene that type of guard rail is typically crumpled up.

Not all industrial guard rail comes with only a 10,000-lb impact rating. Some manufacturers build guard rail to a stronger 13,000-lb impact rating. The added value that a higher-rated guard rail brings to a facility is an increased level of safety and peace of mind. Clearly, a higher-rated guard rail will withstand a more severe impact. Furthermore, 13,000-lb impact rated guard rail has a lower deflection rate than 10,000-lb guard rail.

For example, when a forklift strikes 10,000-lb impact rated guard rail traveling at 4 mph, it can deflect, or push back, up to 12-15 in. When that same forklift strikes 13,000-lb impact rated guard rail, it typically deflects only 10 in. A few inches may not seem that great, but in facilities and distribution centers where space is often at a premium, those few inches mean that equipment and fixtures will be protected and additional manufacturing or storage space can be obtained. It’s important to check the impact rating on any guard rail purchased. That’s because some manufacturers don’t list an impact rating for their guard rail.

The likely reason is that the guard rail was never tested or failed an impact test, and the manufacturer didn’t want to spend the time, money, or resources to redesign it. So the manufacturer goes to market with a product that isn’t rated. These are guard rails to avoid because their impact rating isn’t known.

The testing process

The purpose behind certified testing of guard rail is to demonstrate and prove that it is actually able to handle and deflect the specified amount of weight that it was designed to withstand. Reputable manufacturers will enlist the services of a registered professional engineer or seek an independent, outside firm to oversee the testing process.

In testing 13,000-lb impact rated guard rail, two guard rail assemblies were bolted to a 5 in. by 5 in. by 3/16-in. column. The base plate was 12-in. square and 3/4-in. thick; base plate holes measured 5/8-in. diameter. The column assemblies were properly secured to a concrete floor using 4-in. and 1/2-in. diameter by 4-3/4-in. long Rawl anchor bolts. A 12,700-lb forklift with a 200-lb driver was driven into a marked midpoint on the guard rail at 4 mph.

The resulting impact showed that the guard rail did its job and successfully stopped the forklift’s forward progress. The guard rail was permanently deflected at both the lower and upper rails. The measured permanent deflection was only 5-3/4-in. on the bottom rail and 4-3/4-in. on the upper rail. The anchors on the column remained in place, and there was no damage to the columns in the areas of the holes. While both rails were damaged and would have to be replaced, both maintained their structural integrity and protected everything beyond the deflection of the rails.

Hathaway is a guarding products specialist for Wildeck Inc., a U.S. manufacturer of space enhancement, material handling, and safety guarding products. For more information go to www.wildeck.com.



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