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Quizzes > Science

What to do if a laboratory fire erupts: lab fire safety quiz

Quick, free quiz to check your immediate lab fire actions. Instant results.

Editorial: Review CompletedCreated By: Aurelie MazieresUpdated Aug 27, 2025
Difficulty: Moderate
2-5mins
Learning OutcomesCheat Sheet
Paper art illustration for lab safety quiz on coral background

This quiz helps you practice what to do if a laboratory fire erupts and make quick, safe choices in the first minutes. Use it to spot gaps, handle flammables wisely, and know when to evacuate or suppress a small flame. For broader practice, try the chemistry lab safety quiz, review the fire extinguisher safety quiz, or take a laboratory safety test.

What is the first action you should take if you see a small, controllable fire in the lab?
Call the fire department before doing anything
Attempt to extinguish it using the appropriate fire extinguisher
Evacuate immediately without attempting control
Ignore it and continue working
For a small, contained fire that you are trained to handle, you should use the proper extinguisher following the PASS technique to prevent spread. Always confirm that you have a clear escape path before engaging. Attempting to put it out immediately can protect lives and assets when performed safely.
Which class of fire extinguisher is used for flammable liquid fires?
Class C
Class B
Class D
Class A
Class B extinguishers are specifically designed for fires involving flammable liquids like solvents and oils. They work by interrupting the chemical reaction at the surface of the burning liquid. Using the wrong class can be ineffective or dangerous.
Which type of extinguisher should NOT be used on electrical fires?
Carbon dioxide extinguisher
Dry powder extinguisher
Foam extinguisher
Water-based extinguisher
Water-based extinguishers conduct electricity and can cause electric shock on electrical fires. Carbon dioxide or dry chemical extinguishers are safe choices because they do not conduct electricity. Always use the correct extinguisher type for electrical hazards.
What does the acronym PASS stand for when using a fire extinguisher?
Pull, Adjust, Squeeze, Sweep
Push, Align, Squeeze, Sweep
Pull, Aim, Squeeze, Sweep
Pull, Aim, Shoot, Sweep
PASS (Pull the pin, Aim at the base of the fire, Squeeze the lever, Sweep the nozzle) is the standard method for operating portable fire extinguishers. This method maximizes extinguishing effectiveness and safety. Deviating from this sequence can reduce control over the fire.
If a coworker's clothing catches fire, what is the recommended response?
Use a fire extinguisher on them
Run to the nearest shower
Smother with paper towels
Stop, drop, and roll
Stopping, dropping, and rolling smothers flames by cutting off oxygen. Running can intensify the fire by fanning the flames. A fire extinguisher can cause injury if used on a person without control. Always ensure emergency medical evaluation afterward.
What safety equipment must always be easily accessible in the lab?
Autoclave
Fire extinguisher
Centrifuge
Refrigerator
A fire extinguisher must be within easy reach to tackle small fires quickly. Obstructed extinguishers can delay response time and lead to larger incidents. Regular lab inspections ensure equipment remains accessible.
Flammable liquids should be stored in which type of cabinet?
Acid storage cabinet
General storage cabinet
Flammable storage cabinet
Refrigerated storage cabinet
Flammable storage cabinets are designed to contain spills, resist fire for a period, and vent vapors safely. Using the correct cabinet reduces the risk of fire spread and vapor accumulation. Acids and general chemicals require different storage.
The 'fire triangle' consists of fuel, heat and what third element?
Oxygen
Pressure
Nitrogen
Light
The fire triangle's three elements are fuel, heat, and oxygen. Removing any one component extinguishes the fire. Understanding this helps in selecting suppression strategies.
Before lighting a Bunsen burner, you should always do what?
Use a cell phone flashlight
Check for gas leaks
Wear open-toed shoes
Place flammable solvents nearby
Inspecting hoses and connections for leaks prevents unseen gas buildup that could ignite explosively. Never introduce ignition sources near a leaking burner. Proper pre-checks are a fundamental safety step.
When you hear the fire alarm in the lab, what should you do?
Call your supervisor first
Hide under the bench
Finish your experiment then leave
Immediately evacuate and report to the assembly area
Upon hearing the alarm, you must stop work, turn off equipment if safe, and exit to the assembly point. Delaying evacuation can place you at greater risk. Follow the lab's emergency procedures immediately.
What item is specifically designed to extinguish a small fire on a person?
Safety shower
Eye wash station
Fire blanket
Fire extinguisher
Fire blankets smother flames on clothing by cutting off the oxygen supply. They are safer than extinguishers for use on people. Safety showers are for large-scale decontamination, not immediate flame suppression.
What color band designates a CO2 fire extinguisher?
Blue
Yellow
Black
Red
CO2 extinguishers have a black top band to distinguish them from other types. This visual coding ensures quick identification during an emergency. Using the wrong extinguisher can be ineffective or dangerous.
What is the maximum amount of flammable liquids allowed outside a flammable storage cabinet in a typical lab area?
25 gallons
55 gallons
1 gallon
10 gallons
OSHA and NFPA guidelines limit the amount of flammable liquids outside approved storage cabinets to 10 gallons per control area. This reduces the risk of large-scale fire spread. Exceeding this limit requires special storage provisions.
What class of fire is characterized by burning metal and requires a Class D extinguisher?
Class D
Class B
Class A
Class C
Class D fires involve combustible metals like sodium and magnesium. They require a specialized dry powder extinguisher that smothers the metal. Other extinguishers can react dangerously with burning metals.
Which agent is best for extinguishing a sodium metal fire?
Carbon dioxide
Water
Foam
Dry powder
Water and CO? react violently with sodium, intensifying the fire. Specialized dry powder for metal fires forms a crust that starves the reaction of oxygen. Always use the correct extinguishing media for metal fires.
By using a dry chemical fire extinguisher, which element of the fire triangle are you primarily removing?
Oxygen
Heat
Pressure
Fuel
Dry chemical agents coat the fuel surface and interrupt the chemical chain reaction by displacing or blocking oxygen. This removal of oxygen stops combustion. Different extinguishers may also cool the fire, but the primary action is oxygen exclusion.
Before leaving the lab, what must you do with any open gas lines?
Leave them open
Turn off the main gas valves
Disconnect the hose completely
Just close the Bunsen burner
Shutting off the main gas supply prevents leaks that could accumulate and ignite. Simply closing the burner may not stop line leaks. Full valve closure is required at the end of operations.
The Lower Explosive Limit (LEL) defines what?
Maximum vapor concentration to burn
Minimum vapor concentration to ignite
Temperature at which a liquid boils
Flash point
LEL is the lowest concentration of vapor in air that can ignite. Concentrations below this are too lean to sustain combustion. Understanding LEL helps design ventilation to keep vapors below flammable levels.
In the event of a fire inside a chemical fume hood, what is the recommended first step?
Remove chemicals quickly
Turn on the hood blower
Close the sash
Open the sash fully
Closing the sash starves the fire of oxygen and contains heat and smoke within the hood. Opening the sash can feed the fire with fresh air. After containment, follow fire response protocols.
The flash point of a liquid is the lowest temperature at which it will produce enough vapor to what?
Freeze solid
Boil violently
Ignite in air
Absorb moisture
Flash point is the lowest temperature where vapors above a liquid can ignite if an ignition source is present. It is a key parameter in handling and storage of flammable liquids. Liquids with lower flash points are more hazardous.
Why might using CO2 extinguishers in a sealed lab room pose an additional hazard?
Increases fire temperature
Risks of asphyxiation
Causes electric shock
CO2 corrodes metal equipment
CO2 displaces oxygen and can create an oxygen-deficient atmosphere, leading to asphyxiation. Proper ventilation and evacuation protocols are critical when using CO? extinguishers in confined spaces. Always assess the risk before deployment.
Which type of chemical should NOT be stored in a flammable storage cabinet?
Alcohols
Ketones
Oxidizers
Paint thinners
Oxidizers can react violently with flammable liquids, increasing fire risk. They must be stored separately in oxidizer cabinets. Flammable cabinets are exclusively for flammable and combustible liquids.
What training should laboratory personnel receive regarding fire extinguishers?
None
Written instructions only
Online video only
Hands-on training in the PASS technique
Effective fire extinguisher training combines hands-on practice with the PASS method. Practical experience builds confidence and ensures proper response under stress. OSHA mandates that employers provide both instruction and demonstration.
What is the safe headspace to leave when filling a flammable solvent waste container?
75%
50%
10%
25%
Leaving about 50% headspace prevents overfilling and allows for pressure changes. Too little headspace can lead to rupture if vapors expand or if the container is heated. Proper headspace is required by safety standards.
Why should you not use water (Class A extinguisher) on a Class B (flammable liquid) fire?
Water cools too slowly
Water reacts chemically with flammable liquids
Water is too expensive
Water can spread the burning liquid
Water can spread flammable liquids, increasing the fire's surface area and intensity. Class B extinguishers displace oxygen or interrupt the chemical reaction without dispersing fuel. Using water on flammable liquids is ineffective and dangerous.
What type of ventilation system helps prevent the buildup of flammable vapors in the lab?
Standard ceiling fan
Portable heater
Open window
Explosion-proof ventilation
Explosion-proof ventilation uses motors and controls designed to prevent ignition of flammable vapors. Ordinary fans or open windows cannot guarantee safe dissipation of vapors. Proper design follows NFPA and OSHA guidelines.
According to NFPA 30, what clearance must be kept between stored flammable liquids and overhead sprinkler deflectors?
6 inches
0 inches
2 inches
12 inches
NFPA 30 requires a minimum 2-inch clearance below sprinkler deflectors to ensure effective water distribution during a fire. Insufficient clearance can impede sprinkler performance. Adhering to this standard maximizes fire suppression capabilities.
What is the proper method to dispose of small quantities of flammable solvent waste?
Evaporate in the fume hood
Mix with bleach in a container
Pour down the sink with water
Use an approved, sealed waste container
Approved waste containers are designed to contain vapors and prevent leaks or spills. Pouring down sinks or evaporating in hoods can release hazardous vapors into the environment. Regulations require sealed, labeled waste cans.
When transferring flammable liquids between containers, what practice helps prevent static discharge?
Wearing rubber gloves
Grounding and bonding the containers
Shaking the containers
Using plastic funnels
Grounding and bonding equalize electrical potential between containers, preventing sparks from static buildup. Static discharge can ignite vapors. This practice is mandatory under NFPA and OSHA standards.
While transporting flammable chemicals on a cart, which is required?
Secondary containment and sealed containers
Containers unsealed
Cart must be metallic
Cart must be left in the hallway
Secondary containment prevents spills from spreading if a container fails. Sealed containers reduce vapor release. This minimizes risk during transport.
What device prevents a flame from traveling back into gas supply lines?
Flash arrestor
Pressure gauge
Check valve
Regulator
A flash arrestor stops flame propagation by quenching the flame front in the gas line. This device is critical for torch and burner safety. Without it, flame can travel back to the supply tank.
Under NFPA definitions, liquids with a flash point below what temperature are classified as highly flammable?
100°F (37.8°C)
32°F (0°C)
73°F (22.8°C)
212°F (100°C)
NFPA classifies liquids with flash points below 73°F as highly flammable due to their low ignition thresholds. Recognizing this helps in storage and handling decisions. Higher flash points pose lower immediate fire risks.
How should compressed gas cylinders be stored relative to flammable solvent cabinets?
Inside the flammable cabinet
In a separate, well-ventilated area
Tied together with solvent containers
On top of the cabinet
Separating gas cylinders from flammable liquids prevents combined hazards and ensures proper ventilation. Storing them inside cabinets is unsafe and against code. Always follow cylinder storage guidelines.
In the NFPA 704 diamond, what hazard does the blue quadrant represent?
Flammability hazard
Health hazard
Reactivity hazard
Special hazard
The blue quadrant of the NFPA 704 diamond indicates health risks posed by the material. Red is flammability, yellow is reactivity, and white is for special hazards. Labels guide emergency responders.
What is the maximum fill level for a safety can used for flammable solvents?
95%
25%
100%
50%
Filling safety cans to 95% allows for vapor expansion and prevents overpressure. Overfilling can cause leakage or container failure. Compliance with this limit reduces spill and fire risks.
Which OSHA regulation requires employers to provide portable fire extinguisher training?
29 CFR 1926.21
29 CFR 1910.1450
29 CFR 1910.157
29 CFR 1910.120
OSHA standard 1910.157(c) mandates training for employees on portable fire extinguisher use. This ensures workers can respond to small fires safely. Other standards address different hazards.
What mechanism does foam use to suppress flammable liquid fires, and why is the foam expansion ratio critical?
It forms an insulating blanket that excludes oxygen; expansion ratio determines blanket thickness and stability
It chemically reacts with fuel; expansion ratio controls reaction rate
It absorbs heat and adds pressure; expansion ratio reduces foam volume
It cools the fire only; expansion ratio affects spray distance
Foam fire suppressants blanket flammable liquid surfaces, cutting off oxygen and cooling the fuel. The expansion ratio determines how much air is entrained, which affects blanket stability, coverage, and resistance to fuel and heat. A proper ratio ensures effective suppression without foam breakdown.
Why must labs using inert gas flooding systems incorporate oxygen deficiency hazard (ODH) monitoring, and which standard governs this requirement?
Inert gases react with nitrogen; NFPA 45 mandates monitoring
ODH is not a concern indoors; ISO 9001 addresses it
It prevents corrosion of sensors; OSHA 1910.157 applies
Inert gases can displace oxygen causing asphyxiation; OSHA 29 CFR 1910.34 governs oxygen deficiency monitoring
Inert gas flooding systems used for fire suppression can reduce oxygen levels below safe thresholds, creating ODHs. OSHA 29 CFR 1910.34 outlines requirements for oxygen monitoring and alarms in confined spaces. Continuous monitoring protects personnel from hidden asphyxiation risks.
How does deflagration differ from detonation in vapor cloud fires, and which lab design feature mitigates the risk of deflagration pressure buildup?
Deflagration is supersonic; stronger walls mitigate risk
Deflagration is chemical only; inerting mitigates risk
Deflagration is subsonic flame propagation; explosion venting mitigates overpressure
Deflagration produces shock waves; thicker benches mitigate risk
Deflagration involves subsonic flame travel through a combustible mixture, generating lower peak pressures than detonation but still posing explosion risks. Laboratory designs often include pressure relief vents to safely release pressure and prevent structural failure. Recognizing this difference guides proper safety engineering.
When designing laboratory ventilation to control flammable vapors, why are both lower explosive limit (LEL) and upper explosive limit (UEL) important?
They define the concentration range in which vapors can ignite; ventilation must keep vapor levels below the LEL and avoid accumulation toward the UEL
They determine the flash point
They indicate temperature thresholds for storage
They measure toxicity of vapors
LEL and UEL mark the concentration bounds in which a flammable vapor - air mixture can ignite. Ventilation systems must maintain concentrations below the LEL; if vapors exceed the UEL, they may not ignite but can create hazardous pockets. Proper design ensures vapors remain outside the flammable range.
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Study Outcomes

  1. Apply Fire Emergency Procedures -

    Describe the immediate steps to take if a laboratory fire erupts immediately, including alarm activation, evacuation routes, and use of fire extinguishers.

  2. Demonstrate Safe Handling of Flammable Materials -

    Show correct practices for storing, transferring, and disposing of flammables like alcohol to minimize fire and spill risks.

  3. Explain Responsible Burner Operation -

    Clarify why you should never leave a lit burner unattended and how to monitor heat sources throughout an experiment.

  4. Maintain Proper Personal Protective Equipment -

    Recognize the necessity of wearing laboratory aprons during all lab activities and selecting proper eye protection to guard against splashes and sparks.

  5. Outline Procedures for Incomplete Experiments -

    Detail the steps to follow if a lab experiment is not completed you should, including safe shutdown, labeling, and cleanup processes.

  6. Secure Long Hair in the Laboratory -

    Identify hazards posed by loose hair and demonstrate how long hair in the laboratory must be tied back to prevent contact with flames and chemicals.

Cheat Sheet

  1. PASS Fire Extinguisher Technique -

    If a laboratory fire erupts immediately, use the PASS method (Pull, Aim, Squeeze, Sweep) endorsed by NFPA for effective extinguisher use. This clear framework helps you respond calmly and efficiently to contain small fires. A handy mnemonic - "Pull and Aim, then Squeeze out Flame" - locks in each step under stress.

  2. Safe Burner Practices -

    Never leave a lit burner unattended; OSHA studies highlight that unattended Bunsen burners are a leading cause of lab fires. Always stay within arm's reach and adjust the flame to a gentle blue cone to minimize flare-ups. Label a "Done?" zone on your bench so you remember to turn off heat sources before stepping away.

  3. Mandatory PPE: Aprons and Eye Protection -

    Laboratory aprons should be worn during all lab activities to shield skin and clothing from chemical splashes and heat. Pair aprons with ANSI-approved goggles or face shields - CDC lab safety guides note that eye injuries drop by 90% with consistent eye protection. Store PPE in a dedicated clean zone to encourage regular use.

  4. Securing Hair and Loose Clothing -

    Long hair in the laboratory must be tied back to prevent it from igniting or dipping into chemicals; NIH protocols emphasize secure buns or low ponytails. Use a simple mnemonic like "HAIR - Hold Away In Restricted zones" to recall the rule every time you enter the bench area. Tuck in loose sleeves, and avoid scarves or lanyards near open flames.

  5. Proper Shutdown for Incomplete Experiments -

    If a lab experiment is not completed you should follow shutdown protocols: turn off electrical and gas sources, lock up reagents, and label your workspace with hazard details. According to ACS guidelines, this prevents accidental reactions overnight and ensures colleagues can safely restart. Keep a log of completed steps and pending actions for quick handoff.

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