Confined Spaces and Excavations Questions
CITB confined spaces and excavations questions test whether you can tell when a space counts as confined and what keeps a trench safe, and the right answer usually avoids entry or stops work until the danger is controlled.
Many questions describe a pit, tank, silo or trench and ask whether it is a confined space, or when a supported excavation must be inspected. Our questions are built on the Confined Spaces Regulations 1997, HSE's L101 guidance and regulation 22 of the Construction (Design and Management) Regulations 2015. A common trap: a large space that is easy to walk into can still be a confined space. Take the timed quiz below, then read the 10 sample questions further down, each with a worked explanation. Practise confined spaces and excavations before your CITB Operatives Test or Specialist test, and check yourself with a free Operatives mock test.
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The timed confined spaces and excavations quiz draws from our full set on this topic and explains every answer. The quiz is free: 1 quiz every 7 days without an account, or 30 a day with a free account. A paid plan gives you unlimited quizzes.
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Confined Spaces and Excavations practice quiz (timed)
- questions
- 20
- questions
- minutes
- 30
- minutes
- to pass (90%)
- 18
- to pass (90%)
- Answers and explanations are shown at the end, with every question to review.
- A fresh set of questions every attempt, drawn across CITB's five core knowledge areas.
- About 90 seconds a question, against about 54 in the real test, so there is time to think.
- Every answer comes with a worked explanation.
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How do CITB confined spaces and excavations questions usually ask it?
These questions usually describe a place on site, such as a tank, a pit or a supported trench, and ask whether the rules apply or what must happen before work starts.
| Question pattern | What it looks like, in our words | What the right answer usually does |
|---|---|---|
| Is it a confined space? | A pit, tank, sewer, silo or trench is described, and you decide if the rules apply | Checks that the place is enclosed and that this creates a specified risk, such as fumes, lack of oxygen, fire, drowning or a free-flowing solid like grain |
| When a trench is inspected | Support has gone in, or earth has fallen from a side, and you choose when work may carry on | Picks an inspection by a competent person at the start of the shift and after anything likely to affect its stability |
| Entry, air testing and rescue | Someone is about to go into a tank or chamber, and you pick what comes first | Avoids entry if the job can be done from outside. Otherwise it uses a safe system of work, tests oxygen first and has a rescue plan ready |
Which law and guidance are confined spaces and excavations questions based on?
Our questions are built mainly on the Confined Spaces Regulations 1997 and CDM 2015, with HSE guidance for air testing, rescue and trench support.
| Law or guidance | What the questions take from it |
|---|---|
| Confined Spaces Regulations 1997 | The definition and its specified risks (regulation 1), avoiding entry and using a safe system of work (regulation 4), and rescue arrangements made before entry (regulation 5) |
| HSE L101, Safe work in confined spaces (third edition, 2014) | Why a large space can still be confined, how oxygen runs short, testing oxygen first, permits to work and protecting rescuers |
| Construction (Design and Management) Regulations 2015 | Preventing collapse and falls into an excavation, not overloading the edge, and inspection by a competent person (regulation 22), plus the report when the inspector is not satisfied (regulation 24) |
| HSE, Excavations (construction safety topic page) | Planning support before digging, battering the sides, keeping plant back from the edge and inspecting at the start of each shift |
| HSE HSG150, Health and safety in construction (third edition, 2006) | Never working ahead of trench support, stop blocks for tipping vehicles, and keeping generators away from the edge |
HSE says excavation work should not start until steps have been taken to identify underground services and prevent any risk from them, and Buried Services Questions covers how they are found and dug around safely.
Confined spaces and excavations sample questions with worked explanations
Here are 10 confined spaces and excavations practice questions, each with the answer and a worked explanation.
Sample question 1 · Excavations & Confined Spaces
Regulation 22(1) protects against three specific outcomes. Which is one of them?
- That the excavation is dug deeper than was shown on the drawings
- That the excavation is left open for longer than a single working shift
- That the excavation fills with rainwater during a period of bad weather
- That no person is buried or trapped by material that falls or is dislodgedCorrect answer
Why D: Regulation 22(1) lists collapse of the excavation, dislodging or falling of material from the walls or roof, and burial or trapping of a person by that material.
Sample question 2 · Excavations & Confined Spaces
What other events trigger an excavation inspection under regulation 22(4)?
- A change in the weather forecast for the following working day
- The arrival of a new operative on the site for the first time
- Any event likely to have affected strength or stability, and any fall of materialCorrect answer
- The completion of another metre of additional depth being excavated
Why C: Regulation 22(4)(a) lists the start of the shift, after any event likely to have affected the strength or stability, and after any material unintentionally falls or is dislodged.
Sample question 3 · Excavations & Confined Spaces
Which of these is a 'specified risk' under the Confined Spaces Regulations?
- A risk of a fall from height into the space from the opening above
- A risk of hearing damage from noise reflecting off the space walls
- A risk of manual handling injury while working inside the space
- Serious injury to a person at work arising from fire or explosionCorrect answer
Why D: The definition lists serious injury from fire or explosion, loss of consciousness from raised body temperature, loss of consciousness or asphyxiation from gas, fume, vapour or lack of oxygen, and drowning.
Sample question 4 · Excavations & Confined Spaces
Rescue arrangements are not suitable and sufficient unless they do what?
- Reduce the risks to the people who have to carry out the rescueCorrect answer
- Involve the local fire and rescue service as the first responder
- Guarantee that any casualty will be recovered within ten minutes
- Include a stretcher stored within twenty metres of the entrance
Why A: Regulation 5(2)(a) requires the arrangements to reduce, so far as is reasonably practicable, the risks to the health and safety of any person required to put them into operation.
Sample question 5 · Excavations & Confined Spaces
Why is a lack of oxygen a specified risk?
- Because it causes loss of consciousness or asphyxiation at workCorrect answer
- Because it makes any fire in the space burn more fiercely than usual
- Because it reduces the working life of the tools used in the space
- Because it is the only hazard that gas detection can identify at all
Why A: The specified risk definition covers the loss of consciousness or asphyxiation of any person at work arising from gas, fume, vapour or the lack of oxygen.
Sample question 6 · Excavations & Confined Spaces
Who must be informed if an excavation inspection reveals a problem?
- The enforcing authority, within three days of the inspection
- The designer who specified the depth of the excavation works
- The operatives on the site, at the next daily briefing session
- The person on whose behalf the inspection was carried outCorrect answer
Why D: Regulation 22(5) refers to the inspector informing the person on whose behalf the inspection is carried out, under regulation 24(1), and work stopping until the matter is remedied.
Sample question 7 · Excavations & Confined Spaces
Regulation 22(1) of CDM 2015 requires steps to be taken to prevent danger from an excavation collapsing or material falling. Who does that duty protect?
- The employees of the contractor that dug it, but not other trades
- Any person, whether or not they are working in the excavationCorrect answer
- People working in it, once it is deeper than 1.2 metres
- Members of the public, because workers are covered by other law
Why B: Regulation 22(1) of CDM 2015 requires all practicable steps to be taken to prevent danger to any person, so the duty is not limited to the digging contractor's employees, to deeper excavations or to the public. HSE's guidance puts it the same way: the law says you must prevent danger to workers in or near excavations.
Sample question 8 · Excavations & Confined Spaces
What must the competent person be satisfied about after inspecting?
- That the excavation matches the dimensions shown on the drawings
- That construction work can be safely carried out in the excavationCorrect answer
- That the excavation will not need any further support installing later
- That the excavation can be backfilled at the end of the works there
Why B: Regulation 22(4)(b) requires the person who carried out the inspection to be satisfied that construction work can be safely carried out there.
Sample question 9 · Excavations & Confined Spaces
Heavy rain has fallen overnight on an open excavation. What does the law require?
- Nothing extra, provided the excavation was inspected the previous day
- Inspection, as an event likely to have affected strength or stabilityCorrect answer
- That the excavation is immediately backfilled for safety reasons
- That the excavation is pumped out fully before anyone approaches it
Why B: Regulation 22(4)(a)(ii) requires inspection after any event likely to have affected the strength or stability of the excavation, and rain is a classic example.
Sample question 10 · Excavations & Confined Spaces
A silo is being cleaned out. Which Regulations are most directly engaged?
- The Work at Height Regulations, because the silo is a tall structure
- The Confined Spaces Regulations, since a silo is a listed exampleCorrect answer
- The Manual Handling Regulations, because material must be moved
- The Electricity at Work Regulations, because lighting is required
Why B: Silo is one of the places named in the confined space definition, and a free flowing solid such as grain creates the engulfment and asphyxiation risks the Regulations target.
Which confined spaces and excavations answers catch people out?
The traps are answers that judge a space by its size, trust air that has been shut in, or restart work in a trench before it is inspected.
A confined space is defined by its risk. The Regulations call a place confined when its enclosed nature creates a reasonably foreseeable specified risk, such as fumes or lack of oxygen. HSE's L101 adds that grain silos and ships' holds can be very large and still be confined spaces.
Shut-in air can lose its oxygen with nobody inside. L101 says a steel vessel left closed or poorly ventilated for some time can run short of oxygen as rust forms on the inside. It also says low oxygen acts very fast and usually gives no warning.
A supported trench is inspected at the start of every shift in which work is done in it, after any event likely to affect its strength or stability, and after material falls or is dislodged by accident. Work waits until the competent person who inspected it is satisfied it is safe.
Where does confined spaces and excavations sit in the CITB test?
Confined spaces and excavations are part of the core knowledge you practise for the CITB Operatives test. The Specialist tests include the core questions too, so the same knowledge counts there.
Confined spaces and excavations FAQs
When must an excavation be inspected?
Where supports or battering have been provided, a competent person must inspect it at the start of each shift in which work is done, after any event likely to affect its strength or stability, and after any material falls or is dislodged by accident. Work waits until that person is satisfied it is safe.
Are these the real CITB test questions?
No. These are practice questions written for this site, each tied to the law or HSE guidance it tests; CITB does not publish its test questions.