Glossary

What is a Confined Space?

A confined space is an area with three characteristics at once: limited means of entry and exit, not designed for continuous human occupancy, and capable of developing a dangerous atmosphere — oxygen deficiency, toxic gas, or a flammable mixture. Tanks, silos, tunnels and inspection chambers are common examples.

Glossary Published September 15, 2026 3 min read

01Why it matters

Why it is among the most dangerous work

The danger in a confined space is that the atmosphere inside can change without any sign the person inside would notice. Oxygen deficiency has no smell and no colour, and its first effect is impaired judgement — meaning the first thing a person loses is the ability to recognise they are in danger. Safety here is therefore not measured by how it feels, but by testing the atmosphere before entry and during the work.

The deadliest pattern in confined space incidents is that most fatalities happen among rescuers rather than among those who entered first. A colleague sees someone collapse inside and rushes in unequipped, and is exposed to the same atmosphere within seconds. This is why a trained attendant who stays outside and never enters is a fundamental condition rather than a formality.

02Examples

Examples of confined spaces

Storage and process tanks once emptied.
Silos and mixing vessels.
Tunnels, service ducts and underground inspection chambers.
Boilers and heat exchangers during internal maintenance.
Ship holds and cargo tanks at port facilities.

03Before entry

What must happen before entry

Permit

A written entry permit defining the space, the work, the duration and the crew.
Isolation of sources

Shutting off anything that could feed the space with liquid, gas or energy, and securing that isolation.
Ventilation and testing

Ventilating the space, testing the atmosphere before entry, and retesting periodically during the work.
An attendant

A dedicated person who stays outside for the whole duration, monitors those inside, and does not follow them in.
A ready evacuation plan

A means of extraction and an agreed means of communication, both in place before anyone enters.

04In a Saudi context

In a Saudi context

Oil and gas, petrochemicals and port operations here all involve frequent entries into tanks, vessels and enclosed spaces, most of them inside scheduled maintenance windows where time pressure is at its highest. That intersection — high-hazard work inside a narrow window — is exactly what makes following the pre-entry sequence both harder and more important.

06The product connection

How this relates to SquintPRO

The entry point to a confined space is the clearest thing to monitor: who went in, when, and whether the attendant stayed in position. Defining that point as a zone in SquintPRO means any entry outside the permitted window, or without an attendant present, becomes a case someone is alerted to at the time, with a documented record of every entry. Read about the platform.

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