Shop Safety and Practice

Safety questions look like common sense until two sensible answers appear in the same list. What the subtest is actually testing is whether you know which hazard a given situation presents, because the right protection follows from that.

Personal protective equipment

Enlarge

Zoom in

A face shield does not replace safety glasses; it goes over them. A shield can be lifted or knocked aside, and a shield alone leaves the eyes exposed at the edges.

Hearing loss from noise is permanent and it accumulates. That is why the answer to a question about a loud shop is protection rather than tolerance.

A welding arc damages eyes without any sensation at the time. The burn shows up hours later, which is why the helmet goes on before the arc is struck and why bystanders need screening too.

Tool and machine practice

The rules below are all asked, and every one of them has a mechanism behind it.

Use the right tool for the job. Nearly every shop injury question resolves to somebody substituting a tool that was almost right.

Keep tools sharp. A dull tool needs more force, which is what makes it slip. This is the counterintuitive one, and it is asked.

Cut away from yourself, so a slip carries the blade away from your body.

Clamp the work. An unclamped piece caught by a tool becomes a projectile.

Remove the chuck key before starting. A key left in the chuck is thrown at whatever it is pointing at.

Never remove a guard. Guards are removed for a reason that is never good enough.

Disconnect power before changing a blade or bit, not just switch it off.

Do not carry sharp tools in a pocket, and pass them handle first.

Grind a mushroomed head off a chisel or punch before using it, as the striking tools lesson says.

Keep the floor clear and clean spills at once. Slips account for a large share of shop injuries, and an oil spill near a machine is a worse hazard than the machine.

Fire

Enlarge

Zoom in

The class of a fire is set by what is burning, and using the wrong extinguisher can spread it.

Water on a gasoline fire spreads it, because the fuel floats on the water and carries the fire with it. Water on an electrical fire conducts, which puts the person holding the extinguisher into the circuit.

An ABC dry chemical extinguisher covers the three common classes, which is why it is the one on most shop walls.

The acronym is PASS: pull the pin, aim at the base of the fire, squeeze the handle, sweep side to side. Aim at the base, not at the flames, because the fuel is what has to be smothered.

Rags soaked in oil or finish can ignite without a spark. The oil oxidizes and generates heat, and in a pile the heat cannot escape. Spread them out to dry or store them in a sealed metal container - this is spontaneous combustion, and it is a real question.

Lifting and handling

Lift with your legs, not your back. Get close to the load, keep your back straight, bend at the knees and hips, and stand up.

Keep the load close to your body. A load held at arm's length multiplies the force on your spine, which is the lever lesson applied to you: the farther the weight is from the pivot, the larger the moment.

Do not twist while carrying. Turn with your feet.

Get help or a hand truck for anything awkward, and awkward includes anything that blocks your view.

Ventilation and chemicals

Never run an engine in an enclosed space. Carbon monoxide has no color and no smell, and the first symptoms are a headache and confusion - which is to say, the symptoms interfere with recognizing them.

Solvents and fuels give off vapors heavier than air, which pool at floor level where an ignition source is likely to be.

Battery acid is sulfuric acid. Flush with water for a long time, and note that a charging battery gives off hydrogen, which is why sparks near a battery are dangerous.

Read the label. Chemical safety information is required to be available, and "ask someone" is not the exam's answer when a label exists.

Working under a vehicle

A jack lifts; a jack stand holds. A hydraulic jack can leak down or shift without warning, so a raised vehicle is lowered onto rated jack stands before anyone reaches underneath. Both go at the lift points the service manual identifies - a frame rail or reinforced pinch weld - never on sheet metal or a suspension part that can crush or slip. Wheel chocks on the wheels still on the ground keep the vehicle from rolling.

What you can skip

Across the 64 questions on this topic in our bank:

• Regulations and paperwork. OSHA, safety data sheets and lockout procedures never appear by name on Auto and Shop. The questions ask what the safe practice is, not which rule requires it.
• Noise limits in decibels never appear. Know that hearing protection is worn around loud power tools.

Where people lose points

Choosing gloves at a drill press. Loose material near rotating tools is a hazard.

Using water on an oil or electrical fire. Class B and C need the right extinguisher.

Thinking a dull blade is the safer one. It needs more force and slips.

Aiming an extinguisher at the flames. Aim at the base.

Piling oily rags in a corner. They can ignite on their own.

Lifting with a straight-legged bend. Bend the knees and keep the load close.

Work one in under a minute

A small fire starts in a pan of solvent on a workbench. A worker reaches for a water extinguisher. What is wrong with that choice, and what should be used?

Water will spread the fire.

This is a Class B fire, because what is burning is a flammable liquid.

Solvent is lighter than water and does not mix with it. Water sprayed into the pan sinks, the burning solvent floats on top of it, and the whole lot overflows the pan carrying the fire across the bench and onto the floor.

A Class B extinguisher is correct - dry chemical, carbon dioxide or foam - and an ABC dry chemical unit is what most shops have on the wall.

Aim at the base of the fire and sweep, because the point is to cut the burning liquid off from oxygen, and the flames themselves are not the fuel.

Where this leads

This closes Auto and Shop Information. Every tool lesson before it assumed the work was clamped, the eyes were covered, and the right tool was in hand, and this is where those assumptions were written down.