Free Confined Space Practice Test (OSHA 1910.146 Quiz)

This practice test pulls questions from all 12 free lessons. It is a study aid, not an exam for a certificate, and your answers are never stored.

Knowledge check

Confined space practice test: 20 random questions

Each attempt draws 20 questions from the 96-question bank built from our free lessons. Score 80% or higher to pass. Select New random test for a fresh set. Nothing you answer is saved or sent.

Question 1 A confined space meets which of the following conditions?

It is large enough to bodily enterIt has limited or restricted means of entry or exitIt is not designed for continuous employee occupancyAll of the above

Question 2 Which of these is most likely a confined space?

An office break roomA storage tank entered through a top hatch for cleaningA warehouse loading dockA parking garage

Question 3 When does entry into a permit space occur under OSHA's definition?

When both feet are inside the spaceWhen the worker reaches the bottom of the ladderAs soon as any part of the entrant's body breaks the plane of an opening into the spaceWhen the entry supervisor signs the permit

Question 4 Which OSHA standard covers permit-required confined spaces in general industry?

29 CFR 1910.14629 CFR 1926.65129 CFR 1910.13429 CFR 1904.39

Question 5 A large tank is big enough to drive a truck into. Can it still be a confined space?

Yes, if it has limited or restricted entry or exit and isn't designed for continuous occupancyNo, confined spaces must be smallOnly if it is undergroundOnly if it contains toxic gas

Question 6 Which condition describes a space not designed for continuous employee occupancy?

A control room staffed on every shiftA space workers enter only occasionally for inspection, cleaning or repairAn office with one doorA shop floor with large roll-up doors

Question 7 A worker leans head and shoulders into a manhole to look at a valve. Has entry occurred?

No, both feet are still outsideYes, part of the body broke the plane of the openingOnly if the manhole is over 5 feet deepOnly if the worker touches the valve

Question 8 What makes a confined space a permit-required confined space?

Its sizeThe number of openingsIt contains or could contain a serious hazard such as a hazardous atmosphere, engulfment material, a trapping configuration or another serious hazardWhether it is indoors

Question 9 Which of these makes a confined space permit-required?

It has two openingsIt contains or has the potential to contain a hazardous atmosphereIt is located outdoorsIt is larger than 100 square feet

Question 10 The bottom of a hopper slopes downward and tapers to a smaller opening. Which permit-space characteristic is this?

Engulfment materialAn internal configuration that could trap or asphyxiate an entrantA hazardous atmosphereNot a hazard

Question 11 Which sign wording satisfies OSHA's requirement to inform employees about a permit space?

AUTHORIZED PERSONNEL ONLYCAUTION: WET FLOORDANGER: PERMIT-REQUIRED CONFINED SPACE, DO NOT ENTERNO SMOKING

Question 12 When can alternate procedures under 1910.146(c)(5) be used?

Whenever the entry will take less than 15 minutesWhen the only hazard is an actual or potential hazardous atmosphere that continuous forced-air ventilation alone can control, supported by dataWhen the space has an engulfment hazardWhenever an attendant is present

Question 13 Which space could be reclassified as a non-permit confined space?

A tank with a potential hazardous atmosphere controlled by ventilationA space with no atmospheric hazard whose only hazard, a mixer, is locked out from outside before entryA sewer with intermittent hydrogen sulfideA grain bin with grain inside

Question 14 An employer decides workers will never enter its permit spaces. What must it do?

NothingPost a sign only if OSHA asksTake effective measures to prevent employees from entering, and inform them of the dangerWrite a full permit program anyway

Question 15 A non-permit space is converted to store a chemical. What must happen?

Nothing, its classification is permanentThe employer must reevaluate the space and reclassify it as a permit space if necessaryThe space must be demolishedOnly the sign needs to change

Question 16 What documentation is required when a permit space is reclassified as non-permit?

A written certification with the date, location and signature of the person making the determination, made available to entrantsA verbal statement from the entrantA note in the maintenance log onlyNo documentation

Question 17 Below what oxygen level is an atmosphere considered oxygen-deficient?

23.5%20.9%19.5%16%

Question 18 Above what oxygen level is an atmosphere considered oxygen-enriched?

20.9%21.5%23.5%30%

Question 19 At what level does a flammable gas create a hazardous atmosphere under 1910.146?

Any detectable amountMore than 10% of its lower flammable limitMore than 50% of its lower flammable limitAt its upper flammable limit

Question 20 How can combustible dust at its lower flammable limit be approximated visually?

Any visible dustDust that obscures vision at a distance of 5 feet or lessDust that covers surfaces 1 inch deepDust you can smell

Question 21 A worker wants to "freshen" a tank's air by bleeding in pure oxygen. Why is this dangerous?

Oxygen is toxic at any levelIt can create an oxygen-enriched atmosphere where materials ignite and burn violentlyOxygen is heavier than airIt is not dangerous

Question 22 Which gas has a rotten-egg odor at low levels but deadens the sense of smell at higher concentrations?

Carbon monoxideMethaneHydrogen sulfideNitrogen

Question 23 Which is an example of an engulfment hazard?

A noisy pumpGrain or sand in a bin that can flow and bury a workerA ladder in a manholePoor lighting

Question 24 Rusting steel inside a closed tank can create which hazard?

Oxygen deficiency, because rusting consumes oxygenOxygen enrichmentCombustible dustEngulfment

Question 25 In what order must the atmosphere in a permit space be tested?

Toxics, flammables, oxygenFlammables, oxygen, toxicsOxygen, combustible (flammable) gases, then toxic gases and vaporsAny order is acceptable

Question 26 Why is oxygen tested first?

It's the cheapest sensorMany combustible gas sensors need adequate oxygen to read accurately, and low oxygen is immediately dangerousOSHA doesn't explain whyOxygen is the only gas that matters

Question 27 What is a bump test?

A brief exposure of the sensors to a known gas to confirm they respond and alarm, without adjusting the instrumentDropping the monitor to check it's ruggedA full adjustment of sensor readings to match a known gasA test of the battery only

Question 28 A worker tests only at the manhole opening, and the reading is fine. What's the problem?

Nothing, that's all that's requiredGases can stratify, so the space must be tested at several levels, including near the bottom where heavy gases settleThe opening is always the most dangerous pointThe monitor must be placed inside before testing

Question 29 Who may observe pre-entry atmospheric testing?

Only the entry supervisorAuthorized entrants or their authorized representativesOnly OSHA inspectorsNo one

Question 30 What should happen when a gas monitor alarms during entry?

Silence it and finish quicklyEvacuate the space immediately and reevaluate before re-entryMove to a different part of the spaceIncrease the alarm setpoint

Question 31 Under the construction standard, when may an employer use periodic instead of continuous atmospheric monitoring?

Whenever it's more convenientWhen it can show continuous monitoring equipment isn't commercially available or periodic monitoring is sufficientOnly in spaces under 5 feet deepNever

Question 32 Which gas commonly settles near the bottom of a space because it's heavier than air?

MethaneHydrogen sulfideOxygenHydrogen

Question 33 What is purging?

Ventilating a space before entry to remove or dilute contaminants until testing shows acceptable conditionsFilling a space with nitrogen to prevent fireTesting the air at three levelsCleaning a space with water

Question 34 Where should a supply blower's intake be placed?

Next to the generator for convenienceUpwind and away from engine exhaust and other contaminant sourcesInside the confined spaceDownwind of the vehicle exhaust

Question 35 Why should the supply duct reach the work area or bottom of the space?

It's easier to secureSo fresh air sweeps the space and reaches the entrant instead of short-circuiting at the openingOSHA requires the duct to touch the floorTo keep the duct clean

Question 36 Why must a confined space never be ventilated with pure oxygen?

Oxygen is toxicOxygen is too expensiveIt can create an oxygen-enriched atmosphere above 23.5%, a severe fire hazardOxygen sinks to the bottom

Question 37 A space is 500 cubic feet, the blower delivers 500 CFM effective, and the program calls for 7 air changes. What is the estimated purge time?

1 minute5 minutes7 minutes35 minutes

Question 38 Under alternate procedures, how long must continuous forced-air ventilation run?

Until the first test is acceptableFor 10 minutesUntil all employees have left the spaceOnly during lunch breaks

Question 39 Which ventilation method is best for removing welding fumes at the point they're generated?

Supply only, pointed at the ceilingExhaust (local extraction) near the source, often with supply airNo ventilationPure oxygen

Question 40 After calculating purge time and running the blower, what must happen before entry?

Test the atmosphere at all levels to confirm acceptable entry conditionsNothing, the calculation proves it is safeTurn the blower off to get an accurate readingAsk the entrant if it smells OK

Question 41 What does "isolation" mean in OSHA's confined space standard?

Keeping unauthorized people away from the openingRemoving the space from service and protecting it against the release of energy and material into itVentilating the space with fresh airPlacing the attendant at a distance

Question 42 What is blanking or blinding?

Absolute closure of a pipe or line with a solid plate that covers the bore and withstands maximum line pressureTurning off the lights in a spaceClosing one valve and tagging itCovering the entry opening with a tarp

Question 43 Double block and bleed means:

Two people check every valveClosing and locking two in-line valves and opening a drain or vent valve between themBleeding pressure twice from one valveBlocking the space with two barriers

Question 44 Is a single closed and locked valve generally considered isolation for permit-space entry?

Yes, alwaysNo, valves can leak or be opened; use blanking, double block and bleed or line removalOnly for water linesOnly in construction

Question 45 Which standard covers lockout/tagout of hazardous energy in general industry?

29 CFR 1910.13429 CFR 1910.14729 CFR 1926.65229 CFR 1904.39

Question 46 After applying locks to a mixer inside a tank, what is the final step before entry?

Remove the locks so the entrant can test the mixerVerify isolation, for example by trying to start the equipment and testing for zero energyTurn the mixer on briefly to confirm it worksNothing more is needed

Question 47 In a construction sewer entry with possible upstream flows, what does Subpart AA require?

An early-warning system that gives entrants enough time to exit if an engulfment hazard developsA second attendant downstreamNothing, flows are not a hazardEntrants must wear waders

Question 48 Where must isolation measures be recorded?

Only in the maintenance logOn the entry permit, as measures used to isolate the space and eliminate or control hazardsThey don't need to be recordedOn the attendant's timecard

Question 49 Who signs the entry permit to authorize entry?

The attendantAny authorized entrantThe entry supervisorThe rescue service

Question 50 How must the completed permit be made available to entrants?

It must be filed in the officePosted at the entry portal or made available by another equally effective means at the time of entryEmailed to each entrant the next dayIt doesn't need to be shown to entrants

Question 51 How long may an entry permit last?

24 hoursOne weekNo longer than the time required to complete the assigned task or job on the permitUntil it's lost

Question 52 How long must canceled entry permits be kept?

30 days90 daysAt least 1 year30 years

Question 53 Which item must be on the permit?

The entrants' home addressesThe results of initial and periodic atmospheric tests, with tester names or initials and timesThe weather forecast for the weekThe cost of the job

Question 54 When must the entry supervisor cancel the permit?

When entry operations are completed or a condition not allowed under the permit arisesAt the end of each hourOnly if OSHA requests itWhen the attendant takes a break

Question 55 Under the construction standard, what may an entry supervisor do instead of canceling a permit after an unexpected evacuation?

Ignore the eventSuspend the permit, then return the space to the acceptable entry conditions before re-entryExtend the permit by 24 hoursTransfer it to another space

Question 56 Which additional permit must be listed on the entry permit when welding is done inside the space?

A building permitA hot work permitA parking permitNo other permit is listed

Question 57 Authorized entrants must do which of the following?

Know the hazards, including signs, symptoms and consequences of exposureCommunicate with the attendant as necessaryExit as quickly as possible when ordered to evacuateAll of the above

Question 58 An entrant starts to feel dizzy and develops a headache. What should they do?

Finish the task quicklySit down and rest inside the spaceAlert the attendant and exit as quickly as possibleRemove their respirator

Question 59 Which is NOT one of the four conditions that require an entrant to exit?

The attendant or entry supervisor orders evacuationAn evacuation alarm is activatedThe entrant detects a prohibited conditionThe entrant's shift is almost over

Question 60 What right does an authorized entrant have regarding atmospheric testing?

To observe pre-entry and subsequent testing, and to request reevaluation of the spaceTo skip testing if experiencedTo set their own alarm limitsNone

Question 61 Why must entrants act on early symptoms rather than wait?

OSHA requires a written report firstMany atmospheric hazards impair judgment and coordination, so delay can make self-rescue impossibleSymptoms always go away on their ownIt isn't important

Question 62 What should happen if communication between the entrant and attendant is lost?

Keep working until contact returnsFollow the communication plan, which usually means evacuatingThe attendant enters to checkNothing

Question 63 Where is the retrieval line typically attached to an entrant's harness?

At the waist beltAt the center of the back near shoulder level, or above the headAt the ankleIt isn't attached

Question 64 Hydrogen sulfide is detected by smell, so an entrant who no longer smells rotten eggs is safe. True or false?

TrueFalse. High H2S concentrations can deaden the sense of smellTrue if the space is ventilatedTrue if the entrant wears gloves

Question 65 Where must the attendant be during entry operations?

Outside the permit space until relieved by another attendantInside, next to the entrantIn the site officeAnywhere within 100 feet

Question 66 An entrant begins slurring words and laughing for no reason. What should the attendant do?

Wait to see if it passesEnter to check on the entrantOrder immediate evacuation, since these may be behavioral effects of hazard exposureCall the entrant's supervisor tomorrow

Question 67 An entrant collapses. What should an untrained attendant do?

Enter immediately to pull them outSummon rescue services and perform non-entry rescue, such as using the retrieval system, from outsideLeave to find the supervisorWait for the entrant to wake up

Question 68 Which is a duty of the attendant?

Signing the entry permitContinuously maintaining an accurate count of authorized entrants in the spaceCalibrating the gas monitorPerforming the work inside the space

Question 69 A worker from another crew starts to climb into the space. What must the attendant do?

Warn them to stay away, tell them to exit if they've entered, and inform the entrants and entry supervisorIgnore it if they look experiencedLet them in if they have a hard hatLeave the opening to escort them away

Question 70 Which situation outside the space should cause the attendant to order evacuation?

A delivery truck arriving at the other end of the siteA vehicle idling near the ventilation blower intakeClouds in the skyA phone call

Question 71 May one attendant monitor more than one permit space?

NeverAlwaysOnly if the employer's program includes the means and procedures to do so safelyOnly on weekends

Question 72 The attendant is asked to also run the pump and fill out timesheets. What's the rule?

That's fine if they have timeThe attendant may perform no duties that might interfere with the primary duty to monitor and protect the entrantsThey can, as long as the entry supervisor agreesOnly paperwork is allowed

Question 73 What must the entry supervisor verify before endorsing the permit?

Only that the entrants are wearing hard hatsThat permit entries are made, specified tests are conducted, and procedures and equipment are in placeThat the weather forecast is clearThat the attendant has a phone

Question 74 Who is responsible for terminating entry and canceling the permit?

The attendantThe rescue teamThe entry supervisorThe last entrant out

Question 75 What must the entry supervisor confirm about rescue services?

That they are available and the means to summon them are operableThat they are on site at all timesThat they have visited the site beforeNothing; that's the attendant's job

Question 76 An unauthorized worker tries to enter the space during an entry. What must the entry supervisor do?

Let them in if the space is safeRemove the unauthorized individualAdd them to the permit without trainingReport it at the end of the week

Question 77 What must happen when entry supervisor responsibility is transferred at a shift change?

NothingThe incoming supervisor determines that operations remain consistent with the permit and acceptable conditions are maintainedAll entrants must leave and a new permit is always requiredThe attendant takes over as supervisor

Question 78 Can the entry supervisor also serve as the attendant?

NeverYes, if trained and equipped for that role, while meeting all attendant dutiesOnly in constructionOnly for spaces under 5 feet deep

Question 79 What does "verify by checking" mean for the entry supervisor?

Asking the crew if everything is donePersonally confirming test results, isolation, equipment, people and rescue arrangementsReading yesterday's permitSigning first and checking later

Question 80 When should the entry supervisor recheck conditions during a long entry?

Only at the endAt intervals dictated by the hazards and operations being performedEvery 8 hours exactlyNever, once the permit is signed

Question 81 When must retrieval systems or methods be used?

Only in spaces deeper than 20 feetWhenever an authorized entrant enters a permit space, unless they would increase overall risk or not contribute to rescueOnly when the entrant requests itNever in general industry

Question 82 For what spaces must a mechanical retrieval device be available?

All horizontal spacesVertical-type permit spaces more than 5 feet deepSpaces with two or more openingsOnly spaces with hydrogen sulfide

Question 83 Where should the retrieval line attach to the entrant's harness?

At the front of the waistAt the center of the back near shoulder level, or above the headAt the kneeAt the ankle

Question 84 How often must an in-house rescue team practice permit space rescues?

Every 5 yearsEvery 3 yearsAt least once every 12 monthsOnly after an incident

Question 85 What first aid and CPR requirement applies to rescue teams?

NoneEach member is trained in basic first aid and CPR, and at least one member with current certification is availableOnly the team leader needs CPR trainingCPR is optional

Question 86 What must an employer evaluate before relying on an outside rescue service?

Only the costThe service's ability to respond in a timely manner and its proficiency with rescue tasks and equipmentWhether the service has a websiteNothing, any fire department qualifies

Question 87 Which rescue approach should be the first choice?

Self-rescue, with the entrant getting out on recognizing warning signsEntry rescue by co-workersWaiting for the end of the shiftLowering a second worker on a rope

Question 88 When may wristlets be used instead of a harness for retrieval?

Whenever the entrant prefersOnly if the employer can show a harness is infeasible or creates a greater hazardIn all vertical spacesNever

Question 89 Which OSHA standard covers confined spaces in construction?

29 CFR 1910.14629 CFR 1926 Subpart AA29 CFR 1926 Subpart P29 CFR 1910.147

Question 90 Who must evaluate a construction worksite and identify confined spaces before work begins?

The building owner's insurance agentA competent personThe local fire departmentAny laborer

Question 91 Which employer coordinates entry operations when more than one entry employer is working in or near a permit space?

The host employerThe controlling contractorThe rescue serviceThe entry supervisor's union

Question 92 What does Subpart AA allow the entry supervisor to do with a permit after a temporary unexpected condition?

Extend it by a weekSuspend it instead of canceling, then return the space to acceptable entry conditions before re-entryIgnore the conditionTransfer it to another employer

Question 93 What does Subpart AA require for non-isolated engulfment hazards, such as upstream flows in a sewer?

NothingContinuous monitoring with an early-warning system that gives entrants time to exitOnly a written note on the permitTwo attendants

Question 94 Under Subpart AA, how must training be delivered?

Only in EnglishIn a language and vocabulary the employee understandsOnly onlineOnly by OSHA

Question 95 An employer relies on the local fire department for rescue. What does Subpart AA add?

NothingAn arrangement for the emergency service to give advance notice if it will be unavailable to respondThe fire department must be on site for all entriesThe employer must pay the fire department

Question 96 Which is the host employer's main duty?

Sharing information about known permit spaces, hazards and previous entries with the controlling contractorRunning every entryProviding the attendantCalibrating gas monitors

Last reviewed: October 25, 2026 · Free general education based on OSHA 29 CFR 1910.146 and 29 CFR 1926 Subpart AA. It does not replace the site-specific training, written program and hands-on evaluation your employer must provide, and it does not issue a certificate. Nothing you enter on this page is saved or sent.

Confined Space Practice Test

Confined space practice test: 20 random questions

Need Documented Confined Space Training?