HK Confined Space Certified Worker key terms

An enclosed or partly enclosed place where foreseeable dangers include fire, explosion, harmful gas, fume or vapour, oxygen deficiency or enrichment, or engulfment, and where entry and exit are limited or the space is not designed for continuous work.

Under the Factories and Industrial Undertakings (Confined Spaces) Regulation, a confined space declared by the Commissioner for Labour as specified because of its high risk, carrying extra duties such as certification and a prescribed entry procedure.

A worker who holds a valid certificate issued after completing a recognised confined space training course and passing the assessment, and who may therefore work inside a confined space under the required supervision.

A person with the training, experience and knowledge to assess confined space hazards and carry out the required tests, such as atmospheric testing and risk assessment, before and during entry work.

A documented process of identifying all foreseeable hazards in and around a confined space, evaluating how severe and likely each harm is, and deciding control measures before any entry is allowed.

Systematically listing every potential source of harm associated with a confined space, including atmospheric, physical, biological, electrical and mechanical hazards, and the work to be performed inside.

An atmosphere containing less than 19.5 percent oxygen by volume, which can cause impaired judgement, unconsciousness and death, and which must trigger evacuation and no entry without breathing apparatus.

An atmosphere containing more than 23.5 percent oxygen by volume, which sharply increases fire and explosion severity, makes clothing and hair burn readily, and must be corrected before entry.

A gas or vapour that can ignite when mixed with air in certain proportions, detected by a combustible gas meter and measured as a percentage of its lower explosive limit.

The lowest concentration of a flammable gas or vapour in air at which the mixture can ignite; readings are commonly expressed as a percentage of this limit, with entry refused above a set fraction.

A gas or vapour that harms health when inhaled even at low concentration, such as hydrogen sulphide, carbon monoxide or chlorine, requiring detection by a suitable sensor before and during entry.

The use of calibrated instruments to measure oxygen, flammable gas and toxic gas concentrations in a confined space before entry and at intervals during occupancy, with results recorded and acted upon.

A portable instrument, often multi-sensor, that samples the confined space atmosphere and alarms when oxygen, flammable gas or toxic gas readings pass preset warning thresholds.

Checking and adjusting a gas detector against a known reference gas so its readings remain accurate, usually with a bump test before use and full calibration at stated intervals.

Displacing contaminated air, gas or vapour from a confined space by forcing in clean air or an inert gas, so that the atmosphere becomes safe or suitable for the next planned step.

Supplying fresh air into and removing stale air from a confined space, by natural or mechanical means, to keep the atmosphere breathable and below flammable and toxic limits during work.

Mechanical movement of air into a confined space using a blower and ducting, sized and positioned so that fresh air reaches the breathing zone and contaminated air is pushed out.

Replacing air in a confined space with a non-reactive gas such as nitrogen to prevent fire or explosion, which creates an oxygen-deficient atmosphere that is lethal and requires breathing apparatus for any entry.

Physically separating a confined space from every energy source and material supply, using methods such as blanking, disconnection, double block and bleed, or lockout, so nothing can enter unexpectedly.

A procedure in which energy-isolating devices are locked in the safe position and tagged with the owner's details, so equipment cannot be re-energised while workers are inside the space.

Inserting a solid plate or spade into a pipe flange, or otherwise closing off a line, to stop liquid, gas or vapour entering a confined space from connected plant.

Equipment worn to protect the wearer's airways, ranging from filtering masks for known contaminants at safe oxygen levels to supplied-air or self-contained breathing apparatus for unknown or oxygen-deficient atmospheres.

A breathing set worn by the entrant that carries its own compressed air supply, independent of the surrounding atmosphere, and is required where the air is or may be immediately dangerous to life or health.

A small, short-duration breathing device carried by a worker so they can leave a confined space safely if the atmosphere suddenly deteriorates or the main air supply fails.

A strap assembly worn around the body that spreads fall-arrest and retrieval forces, fitted with a lifeline attachment so an unconscious worker can be lifted out of a confined space.

A portable retrieval system set over a vertical entry point, combining an anchorage frame, lifeline and lifting device so a worker can be raised without rescuers entering the space.

A formal written authorisation stating the space, the work, the hazards, the control measures, the test results and the validity period, signed by the authorised issuer before entry and closed on completion.

A person appointed by the employer or contractor to issue, control and cancel confined space entry permits and to verify that the stated precautions are in place before work starts.

The person in charge at the confined space who confirms the permit conditions are met, controls who enters, and orders evacuation when conditions change or an alarm sounds.

A trained worker stationed outside the confined space who maintains communication with entrants, keeps unauthorised people out, watches for change, and raises the alarm without entering to attempt rescue.

A reliable agreed means of exchanging signals between entrants and the standby person, such as radio, lifeline signals or voice, tested before entry and maintained throughout the work.

A pre-planned procedure and equipped team able to reach and remove an injured worker from a confined space quickly, without unprotected rescuers entering and becoming further casualties.

Emergency life support given to a casualty who is not breathing or has no heartbeat, typically cardiopulmonary resuscitation with oxygen and an AED, started as soon as the person is out of the space.

Being buried or smothered by a flowing or collapsing material such as grain, sand, slurry or powder inside a space, which can trap and suffocate a worker within seconds.

A written, site-specific sequence of steps describing how the confined space work is done safely, including preparation, testing, entry, monitoring, exit and emergency arrangements.

A log of each atmospheric test showing date, time, location, instrument used, readings for oxygen, flammable and toxic gas, and the name of the person who performed the test.

A short briefing before work in which the supervisor explains the hazards, control measures, permit conditions, communication arrangements and emergency plan to everyone involved in the entry.