Confined Space Inspection
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Confined Space Inspection
We go inside manholes, valve chambers, pumping stations, tanks and basins to record the actual condition of the concrete, the equipment and the access points, and we produce a signed and sealed report. A camera lowered from the surface shows what can be seen; it doesn't tell you what the structure can still carry.
We work with municipalities, RCMs, asset managers and industrial owners, in a setting where entry is regulated as strictly as the findings that come out of it.
- ROHS · Division XXVICompliant entry, from gathering information to the rescue plan
- Engineers ActInspecting a structure is a reserved act
- Sealed reportFindings that are located, ranked and defensible
I
Six types of structure inspection assignments
A buried municipal structure deteriorates where no one is looking. Linear pipe has been inspected by camera for years; the individual structures that connect it, much less so. Yet that is where you find corroded concrete, rusted rungs and worn cover slabs.
Manholes and valve chambers
Condition of the concrete and joints, corrosion of the rungs, condition of the base slab and channels, pipe inlets and outlets, signs of infiltration. The level of detail is what requires entering the structure, not what can be coded from the surface.
Pumping stations
Condition of the structure, the wet well, equipment supports, anchors, access points and hatches. Problems that look mechanical often turn out to be structural: a loose anchor, a cracked slab, corrosion under a seal.
Tanks and basins
Drinking water reservoirs, retention basins, diversion chambers. Survey of the condition of the walls, the base slab, the waterproof joints and the internal equipment, with the precautions specific to structures in service.
Concrete structural assessment
Telling a shrinkage crack from an active crack, measuring the depth of attack, assessing the loss of reinforcement section. In a wastewater structure, the dominant cause is biogenic corrosion: hydrogen sulfide turns into sulfuric acid on the concrete surface and eats it away from the top down.
Access upgrades
Since 2023, building a new confined space or renovating an existing one must include the equipment needed to intervene from the outside. In practice: certified anchors, davits, platforms, permanent ventilation, remote instrumentation. This has to be designed and sealed.
Classifying structures
A space is only “confined” under the regulation if it actually presents one of the three named risks. Establishing that a structure presents none of them moves it into the “restricted access” category, with much lighter intervention requirements. This demonstration is technical, and it binds the person who signs it.
II
What is a confined space under the regulation?
Since July 2023, the definition in the Regulation respecting occupational health and safety no longer depends on the shape of the structure but on the risks it presents. A fully or partially enclosed space (tank, vat, chamber, vault, pit, sewer, pipe, access shaft) is a confined space if, because of its confinement, it presents at least one of the following three risks.
The change isn't cosmetic. Under the old definition, a structure was classified on its physical characteristics; it is now classified on an assessment of the actual risks.
Two identical manholes can therefore fall under different regimes depending on what they receive.
- An atmospheric or thermal risk: asphyxiation, poisoning, loss of consciousness or judgment, fire or explosion.
- A risk of engulfment: linked to the presence of free-flowing solids.
- A risk of drowning or being swept away: linked to the level or flow of a liquid.
- None of the three: the structure is then not a confined space within the meaning of Division XXVI, but that has to be demonstrated and owned.
III
The situations that call for an inspection
An owner of structures doesn't send a crew down as a general precaution. Here are the four triggers we see most often.
- Plan
The intervention plan says nothing about individual structures
It focuses mostly on pipes and roadways. Manholes, chambers, stations and reservoirs rarely appear in it with reliable condition data, even though they are the most expensive to replace in an emergency.
- Document
The prevention program has to be up to date
Since October 2025, the permanent occupational health and safety regime has required an updated action plan or prevention program. Documenting an organization's confined spaces (where they are, what risks they present, how they are entered) becomes a required deliverable.
- Correct
A problem keeps coming back in the same place
A recurring backup, a roadway sinking around a manhole, infiltration in a station. A visual check from the surface tells you neither the cause nor the urgency; someone has to go down.
- Rebuild
A structure is being rebuilt or replaced
Rebuilding a pumping station or valve chamber triggers the obligation to fit out the structure so it can be serviced from the outside. Better to build that into the plans from the design stage than to discover it at the final inspection.
IV
Our approach, from preparation to report
Entry is the visible part of the assignment. Preparation determines whether it is safe, and the report determines whether it was worth anything.
- Preparation and information gatheringAtmospheric risks, free-flowing materials, energy sources, access, communications, prevention measures. This information is gathered by a qualified person and available in writing at the work location itself, as section 300 of the regulation requires.
- Making it safeIsolation of energy sources, ventilation, atmosphere readings taken from the surface, an attendant posted outside with two-way communication, accessible rescue equipment and a rescue plan tested through drills.
- Survey inside the structureConcrete, joints, base slab, rungs, anchors, equipment, pipe inlets and outlets, signs of infiltration. Each finding is located and photographed, with the measurements needed to compare it in five years.
- DiagnosisWhat the finding means. Nature and activity of cracks, depth of attack, loss of section, residual capacity of the cover slab, fitness for service. This is the step a coded inspection from the surface never reaches.
- Report and recommendationsRanked findings, causes, intervention options with their consequences, and a prioritization that can be defended before a municipal council or a funding program. Signed and sealed.
V
What you receive
A structure survey has to serve three purposes: deciding on an intervention, financing it, and proving that the entry was done by the rules. The report covers all three.
- A signed and sealed inspection report: every finding located, photographed and ranked by urgency.
- A survey of the structure: dimensions, materials, connections, depths, condition of the access points. It's the record your asset inventory was missing.
- A diagnosis: explaining the cause of the deterioration and its likely progression, not just its existence.
- Recommendations you can price: repair, lining, reinforcement, replacement, in the order to carry them out.
- Compliance documents for the intervention: information and prevention measures recorded, atmosphere readings entered in the register, rescue plan applied.
Reference framework
- Definition of a confined space
- ROHS, s. 1
- Work in a confined space
- ROHS, Division XXVI (ss. 296.1 to 312)
- Construction and renovation
- ROHS, s. 297.1
- Information and prevention
- ROHS, ss. 300 and 301
- Monitoring and rescue
- ROHS, ss. 308 and 309
- Construction sites
- Safety Code for the construction industry, subdivision 3.21
- Inspection of a structure
- Engineers Act, ss. 2 and 3
- Good practice
- CSA Z1006 (voluntary standard)
Requirements vary depending on whether the structure is in an establishment or on a construction site, and on the owner's own procedures. We confirm the exact framework before entry.
VI
FAQ
How does a confined space inspection work?
It is prepared before anyone goes down. Atmosphere readings taken from the surface, ventilation if needed, an attendant posted at the opening, rescue equipment on hand and a written, site-specific procedure. These are the requirements of Division XXVI of the Regulation respecting occupational health and safety, and there is no way around them. Once inside, the survey covers what has engineering value: condition of the concrete and joints, corrosion of equipment and rungs, condition of the base slab, pipe inlets and outlets, signs of infiltration. The report locates each finding and ranks it.
How is this different from a camera inspection?
A CCTV inspection codes what it sees using a standardized system, along linear pipe, without anyone going in. It's efficient, and it's the right tool for pipes. For an individual structure, what matters happens where the camera doesn't go: behind the deposits on the base slab, under the channel, on the underside of the cover slab, inside the depth of corroded concrete. The manhole inspection standard itself provides for two levels, and the more detailed one explicitly requires a person to enter the structure. That is the one we do.
Why an engineer rather than a technician?
Because it isn't just a question of competence, but of law. The Engineers Act reserves for engineers the inspection of a structure as well as the preparation, signing and sealing of the related reports, and it specifically names the structural components of sewer systems, waterworks and retention basins. A structural condition report produced without an engineer is a problem before anyone even discusses its content.
Does the law set a maximum rescue time?
No, and it needs to be said clearly because the opposite is often claimed. The regulation requires a rescue plan for promptly rescuing the worker, with suitable equipment that is inspected and accessible nearby, a call protocol, a person specifically designated to direct operations, and drills to test the plan. It doesn't set any number of minutes. What sets the real time limit is physiology, not the text.
What concentrations are acceptable before entry?
In an establishment, oxygen must be between 19.5% and 23%, flammable gases and vapours below 5% of the lower explosive limit, and contaminants below the standards in Schedule I of the regulation. This oxygen threshold was raised to 20.5% in July 2023, then brought back to 19.5% in June 2025: several documents still in circulation show the intermediate value. On a construction site, the Safety Code applies its own values, and when the two regimes overlap, we apply the stricter one.
Can you have a structure removed from the “confined space” category?
We can assess whether it actually presents one of the three risks named in the regulation, and document the conclusion. When the answer is no, the structure falls into the “restricted access” category and the requirements of Division XXVI no longer apply, which concretely changes the cost of every maintenance intervention. When the answer is yes, we say so too. The demonstration only has value if it can go either way.
Do you work on structures in service?
Yes, and that is the usual case. A pumping station doesn't stop to be inspected; a tank is rarely drained without consequences for the network. The sequence, energy isolation and flow control are planned with the operator before the day of the work, not that morning.
Next step
A structure to inspect, a portfolio to document?
Tell us which structures you have, what you already know about them and what you need to demonstrate. We'll tell you what requires entry, what doesn't, and where to start.
- Firm
- GC4I Inc., structural engineers
- Office
- 8350 Christophe-Colomb Avenue, Suite 18, Montreal
- Service area
- Montreal, South Shore, North Shore and across Quebec
- contact@gc4i.ca
The provisions cited are those applicable in Quebec when this page was last updated. The exact framework depends on the structure's status, the applicable regime and the owner's own procedures.