An over-torqued bolt can bring the whole machine to a grinding halt.
Metal and alloy bolts are meant to stretch. If a bolt is torqued to engineering spec, a small amount of stretch is normal and won’t cause any future problems. Small stretch doesn’t change the physical properties of the bolt and allows it to get back to its original shape for re-torquing. On the other hand, an over-torqued bolt is stretched so much that its physical properties are changed to the point of compromising its strength and durability. An over-torqued bolt is likely to crack, shear, come loose or break off, and cause major equipment damage or even human injury.

Are you safe?
How can you tell whether the noise or level of vibration in your everyday tools is dangerous? Some U.S. manufacturers list tool noise and vibration levels of their products, but it’s not a requirement—yet. And data alone won’t be helpful if you don’t have a frame of reference.

For example, a typical decibel (dB) level (volume) of an impact gun is up to 100dB. It’s not as bad as a hammer drill (nearly 115dB), but it’s significantly over the normal conversation volume of 60dB. It’s important to understand decibel readings—70dB noises are twice as loud as 60dB. Imagine you’re having a conversation in a restaurant (60dB), and suddenly someone starts vacuuming around your table (70dB). Not only would that be annoying, but also you wouldn’t be able to hear what people at your table are saying. Now turn that up to 100 dB (typical impact gun), and the level of noise becomes literally deafening.

Exposure to HAV depends on both the magnitude (intensity) of vibration expressed as acceleration in meters per second squared (m/s2) and the duration of exposure. The daily vibration exposure action value A(8) for a worker carrying out one process or operating one tool can be calculated from magnitude and exposure duration. According to the European Union Manufacturer’s Directive, if a person is exposed to action value over 2.5 m/s2, action should be taken to lessen the exposure. For example, if an impact gun has a declared vibration emission of 16.5 m/s2, using it for longer than 15 minutes at a time, becomes highly hazardous for the worker.

The National Institute for Occupational Safety and Health (NIOSH)—a division of the CDC—offers helpful guidelines on how to estimate safe levels and limit exposure to dangerous noise and vibrations.

Universal Safety Standards
Another helpful source of power tool safety guidelines is the Manufacturer’s Directives, developed by the E.U. lawmakers. This set of rules requires suppliers to disclose vibration emissions of their tools. However, when reading those, keep in mind that the box refers to brand-new tools and doesn’t take into account everyday wear and tear, which may affect a tool’s vibration emissions.

Some manufacturers are more conscientious than others, and at HYTORC, we hope that companies worldwide can find a way to cooperate in setting reliable (and practical) shared safety standards across industries before international governments require them.

Safety is good business.
Investing in safety makes clear business sense. While the costs of workers’ comp vary by industry, state, and type of injury or illness, insurance claims are just the tip of the expenses iceberg for employers. When calculating safety ROI, employers need to take into account not only the cost of insurance claims, but also expenses and headaches associated with finding another worker to finish the job; any wages paid to the injured employee for absences beyond workers’ comp; costs of schedule disruptions; time spent by employees and specialists who have to handle the claim, etc.

The good news is that safety ROI has been proven again and again by various federal, state, and private-sector programs. Not only do the companies who participate in these programs see a decrease in costs of workers’ compensation and lost worktime, but also they often see increased production and improved employee morale.