Shop Safety & Procedures — ASVAB AS Study Guide

Formula Reference

Eye protection: always wear safety glasses/goggles when grinding, cutting, or working with chemicals

Fire classes: A = ordinary combustibles, B = flammable liquids, C = electrical, D = metals — extinguisher must match

Grounding: always disconnect the negative battery cable first (prevents accidental sparks)

PPE hierarchy: elimination → substitution → engineering controls → PPE — PPE is the last line of defense

Lifting: keep back straight, bend knees, lift with legs — never twist at the waist while holding load

MSDS/SDS: Safety Data Sheet required for every chemical in the shop — lists hazards, handling, and spill response

What the ASVAB is testing

Shop safety questions have definitive answers. The test is checking whether you know established safety protocol — not asking you to weigh trade-offs. If a question seems like a judgment call, it usually isn't: one option is the correct standard procedure, the others are common shortcuts that cause accidents.

The ASVAB covers three safety domains: personal protective equipment (PPE), fire safety, and general shop procedures. Know the rules for each and you can answer these quickly.

Personal protective equipment

Eyes: Safety glasses or goggles are required any time there's flying debris or chemical splash risk — grinding, cutting, welding, battery work. A face shield goes over safety glasses for heavy grinding or splash hazards.

Hands and skin: Gloves protect against cuts, chemicals, and heat. The critical exception is rotating equipment (drills, lathes, grinders) where loose material can be caught and pulled. On those machines, bare hands or fitted gloves only.

Ears: Hearing protection is required when noise exceeds 85 dB. Power tools, air compressors, and pneumatic equipment often exceed this.

Respiratory: Dust masks filter particles; respirators filter chemical vapors. They are not interchangeable — a dust mask doesn't stop paint fumes.

Fire safety

The class system tells you what's burning:

A — wood, paper, cloth (ordinary combustibles)
B — gasoline, oil, solvents (flammable liquids)
C — live electrical equipment
D — combustible metals (magnesium, titanium)

An ABC dry-chemical extinguisher handles most shop fires. Never use water on a Class B or C fire.

Shop procedures

Ventilation is non-negotiable when running engines indoors — CO accumulates in minutes in an enclosed space. Lift heavy objects with your legs, not your back. Keep work surfaces clear so tools don't fall. Store solvents in approved flammable-storage cabinets away from ignition sources.

Test approach

Safety questions reward memorization over reasoning. If you know the PPE for each task and the fire extinguisher class for each fuel type, you'll get these right without calculation.

Common Pitfalls

⚠Using a Class A extinguisher on a flammable-liquid (Class B) fire — water spreads burning fuel

⚠Removing the positive cable first when disconnecting a battery — risk of wrench shorting to chassis

⚠Running an engine indoors without ventilation — carbon monoxide buildup is odorless and lethal

⚠Wearing gloves on a drill press or lathe — rotating equipment can grab loose gloves and pull hands in

⚠Using an air compressor line to blow dust off clothing — high-pressure air can penetrate skin

Worked Examples

Q1: A small fire breaks out in a shop when gasoline spills on a hot surface. Which fire extinguisher class is correct?

Answer: Class B — flammable liquids. A Class A extinguisher uses water, which would spread the burning gasoline. CO2 or dry chemical extinguishers rated for Class B smother the fire by cutting off oxygen or breaking the combustion chain.

Q2: A technician is about to disconnect a car battery to replace it. Which cable should come off first and why?

Answer: The negative (ground) cable first. Removing positive first risks a wrench accidentally bridging from the positive terminal to a grounded part of the body, completing the circuit and causing a spark or short. With negative disconnected first, the circuit is already broken.

Q3: A worker needs to use a bench grinder to smooth a metal edge. Which PPE items are mandatory before starting?

Answer: Safety glasses or a face shield at minimum — sparks and metal fragments travel at high velocity. A leather apron is recommended. Gloves are debated: some shops require them, others prohibit them near rotating equipment. On the ASVAB, eye protection is always the non-negotiable answer for grinding.