Module 4: Safety & Emergency Procedures Assessment Quiz

Module: U5M4 - Safety & Emergency Procedures Duration: 25 minutes Passing Score: 70% Format: Multiple choice and scenario-based

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What is the minimum shade number for a welding helmet when plasma cutting at 40-80 amps?

Shade 9 minimum, Shade 9-12 recommended

Shade 3-5

Shade 5-7

No shade required — safety glasses are sufficient

Submit

Explanation: Plasma arcs at 40-80A produce intense UV and visible light requiring shade 9-12 protection. Lower shades provide inadequate UV filtering and will result in arc eye (photokeratitis). Safety glasses alone offer no protection against the plasma arc intensity. Always wear ANSI Z87.1 safety glasses UNDER the welding helmet.

A student working near the plasma cutter is wearing a polyester t-shirt. What is the immediate safety concern?

Polyester melts into the skin when exposed to sparks or radiant heat, causing severe burns

Polyester generates static electricity that may interfere with the arc

Polyester blocks UV radiation too effectively, causing vitamin D deficiency

There is no concern — polyester is acceptable for plasma cutting

Submit

Explanation: Synthetic fabrics (polyester, nylon, rayon) melt at relatively low temperatures and fuse into the skin when ignited by sparks or exposed to radiant heat. This creates compound thermal + chemical burns that are extremely painful and difficult to treat. Only natural fibers (cotton) or FR-rated clothing should be worn in plasma cutting areas.

How long should fire watch be maintained after plasma cutting operations cease?

A minimum of 30 minutes

5 minutes

Until the metal cools to room temperature

Fire watch is only needed during cutting, not after

Submit

Explanation: Per OSHA and NFPA 51B guidelines, fire watch must continue for at least 30 minutes after hot work (including plasma cutting) is completed. Sparks and molten metal can ignite combustible materials that may smolder for extended periods before producing visible flames. The fire watch person must have a fire extinguisher and know its operation.

During plasma cutting, a student experiences a brief flash of arc light without their welding helmet in position. What should they do?

Stop cutting, report the exposure, and monitor for symptoms of arc eye over the next 6-12 hours

Continue cutting — brief exposure is harmless

Apply sunscreen to their face and continue

Rinse eyes with cold water for 1 minute and resume

Submit

Explanation: Arc eye (photokeratitis) symptoms are delayed — they typically appear 6-12 hours after exposure and include pain, tearing, sensitivity to light, and a gritty feeling. Even brief exposure can cause damage. The student should report the exposure, apply cool compresses if discomfort develops, and seek medical attention if symptoms are moderate or severe.

What is the minimum clearance radius from the plasma cutting area that must be kept free of combustible materials?

35 feet (per NFPA 51B)

5 feet

10 feet

15 feet

Submit

Explanation: NFPA 51B (Standard for Fire Prevention During Welding, Cutting, and Other Hot Work) requires a 35-foot clearance from hot work operations. Sparks and molten metal from plasma cutting can travel significant distances and maintain enough heat to ignite paper, wood, fabric, solvents, and other combustibles.

A coworker receives an electrical shock from the plasma cutter and is still in contact with the circuit. What is the correct first response?

Disconnect power at the main breaker or use a non-conductive object to separate them from the circuit — do NOT touch them directly

Grab them and pull them away from the machine immediately

Throw water on them to break the circuit

Wait for the shock to stop on its own

Submit

Explanation: Touching a person who is in contact with an electrical circuit will cause the rescuer to also receive a shock (the human body conducts electricity). Disconnect power at the main switch/breaker, or use a dry non-conductive object (wood board, dry rope, rubber mat) to separate the victim from the circuit. Call 911, then begin CPR if the victim is not breathing.

Why must containers that previously held flammable materials never be plasma cut without proper purging?

Residual vapors inside the container can be ignited by the plasma arc, causing an explosion

The container walls are too thin for plasma cutting

The previous contents will contaminate the plasma consumables

The container material is not compatible with plasma cutting

Submit

Explanation: Even "empty" containers that held flammable liquids (gasoline, solvents, oils) contain residual vapors that can be in the explosive range. The plasma arc provides more than enough energy to ignite these vapors, causing a container explosion. Containers must be certified purged and gas-free (using CO₂, nitrogen, or water-fill method) by a qualified person before any hot work.

What type of fire extinguisher should be available near the plasma cutting area?

ABC dry chemical or CO₂ — suitable for ordinary, flammable liquid, and electrical fires

Water-based extinguisher only

Foam extinguisher only

No extinguisher is needed if a water table is used

Submit

Explanation: ABC dry chemical extinguishers cover ordinary combustibles (A), flammable liquids (B), and electrical equipment (C) — all of which may be present in a plasma cutting area. CO₂ extinguishers are also appropriate and leave no residue. Water-based extinguishers must NEVER be used on electrical fires. The extinguisher must be within 15 feet of the cutting operation.

A student cuts galvanized steel and develops flu-like symptoms (chills, fever, body aches) 8 hours later. What is the most likely diagnosis?

Metal fume fever from inhaling zinc oxide fumes

Seasonal influenza unrelated to cutting

Electrical shock aftereffects

Heat exhaustion from the plasma arc radiation

Submit

Explanation: Metal fume fever is caused by inhaling zinc oxide fumes produced when the zinc coating on galvanized steel is vaporized by the plasma arc. Symptoms appear 4-12 hours after exposure and include chills, fever, body aches, headache, and nausea. Treatment is supportive (rest, hydration). Prevention requires P100+OV respiratory protection and maximum ventilation when cutting galvanized materials.

What is the proper way to handle metal that has just been plasma cut?

Use pliers or tongs — never bare hands. Mark the metal "HOT" if leaving it unattended. Wait 5+ minutes before handling

Use leather gloves to pick it up immediately

Dip it in the water table to cool it

Blow on it with compressed air to cool it faster

Submit

Explanation: Plasma-cut metal can be 300-800°F for several minutes after cutting. Even leather gloves may not provide sufficient protection against these temperatures. Use pliers or tongs for handling, and mark any hot metal left on the table with soapstone "HOT" to warn others. Quenching in water can cause steam burns and may warp the part. Compressed air does not cool effectively and creates a burn/flying debris hazard.

What must be done if the plasma cutter's E-stop is pressed during a cut?

Wait for all motion to stop, diagnose the cause, verify clear path and consumable condition, then resume or restart as appropriate

Immediately press the start button to resume cutting

Power cycle the entire system and reload the G-code

Nothing — the machine will resume automatically after 30 seconds

Submit

Explanation: After an E-stop, the machine may have lost its position reference. The operator must wait for complete stop, identify why the E-stop was pressed, verify the torch is not touching the workpiece, check consumables for damage (arc interruption can damage the electrode), and verify the path is clear before resuming. Most controllers support "resume from line" to continue the program without re-cutting completed features.

Which of the following is the MOST effective method for reducing plasma cutting fume exposure?

Local exhaust ventilation at the cutting point combined with a water table

General room ventilation (opening doors and windows)

Wearing a dust mask

Cutting at higher speeds to reduce exposure time

Submit

Explanation: Local exhaust ventilation (downdraft table or fume arm positioned at the cutting point) captures fumes at the source before they disperse into the workspace. Combined with a water table (which captures ~90% of particulates), this provides the most effective fume control. General ventilation alone is insufficient. A dust mask (not rated for metal fumes) provides minimal protection. Speed changes do not significantly reduce fume generation.

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Last Updated: 2026-03-19