COMPLETE HEALTH, ENVIRONMENTAL AND SAFETY SERVICES (C.H.E.S.S.)
Toolin' Around (Part Two) by Janet L. Keyes, CIH and Carol A. Keyes, CSP
Editor’s note: Last month, we went over the first two safety requirements for keeping your technicians, tools and shop safe. Here is part two. Electrical tools must be grounded or double-insulated. Grounded tools have a three-prong plug. If the tool is double-insulated, its plug will have only two blades, but the tool will be marked as double-insulated or will have a box within a box symbol. Grounded tools help prevent their users from getting shocked – they provide a better path to ground than the human body. Double insulated tools have all electrical parts isolated from the outside non-conductive case. If the wiring shorts, the user will not be shocked. Keep guards in place and correctly adjusted. The most common violations we see are on bench grinders. The grinding wheels are usually mounted with the required blotters (compressible washers that go between the wheel and the flanges) and with the guard that goes around 75 percent of the wheel. But work rests are often dropped down or not adjusted to within 1/8-inch of the wheel. And it seems that few people know to adjust the tongue guard at the top of the wheel. That has to be within 1/4-inch of the wheel. The work rest keeps the work piece from being sucked into the wheel. The tongue guard protects the user from sparks and from shrapnel if the wheel explodes. The other common violation we see is lack of guarding on hydraulic shop presses. When a bearing has tons of
20 | April 2021
pressure put on it, it can burst and send fragments out toward the user. People have been killed by that. But these presses usually do not come with guards. That does not let you off the hook. It isn’t difficult to fabricate a guard to protect the user against the ejection of parts. Follow the manufacturer’s instructions. Have you read the manual for your bench grinder? One of the instructions it will give is to ring test a new wheel before it is installed. To do that, tap the wheel about a half inch from the edge with something nonmetallic. If you hear a dull thud, the wheel is damaged and must not be used. Damaged or incorrectly mounted grinding wheels can explode, sending chunks flying out at speeds above 60 miles per hour. The guards, if correctly adjusted, will help contain the shrapnel. But preventing a wheel from exploding is safer than containing it. Minnesota explicitly requires you to follow the manufacturer’s instructions. If you want to use a screwdriver as a crowbar and want to comply with OSHA standards, you either need the manufacturer’s written approval or need the okay of someone who can evaluate that use “in accordance with accepted engineering requirements.” Think that is overreach? In 2017, an employee in St. Paul punctured a car tire with a knife. The tire exploded, sending the knife into the worker’s neck. The worker was injured badly enough to require hospitalization. The company received a $3,000 citation for that.
AASP-MN News
