Risk Assessment for Confined Space Entry: What Irish Contractors Must Include

Confined space entry is one of the highest-risk activities on Irish construction sites.

What Is a Confined Space?

A confined space is any place that is substantially enclosed, where there is a reasonably foreseeable risk of serious injury from hazardous substances or conditions within the space or nearby. On Irish construction sites, confined spaces include manholes, sewers, inspection chambers, storage tanks, vaults, tunnels, excavations, and any enclosed area where the atmosphere may be deficient in oxygen or contaminated with toxic or flammable gases.

The key characteristic of a confined space is not its size but the nature of the hazards it presents. A large underground chamber can be a confined space if it contains a hazardous atmosphere. A small manhole can be a confined space even if it appears to be well ventilated, because the atmosphere can change rapidly.

The Legal Framework

Confined space entry on Irish construction sites is governed by the Safety, Health and Welfare at Work (General Application) Regulations 2007, Part 2 Chapter 5 (Work in Confined Spaces), and the Safety, Health and Welfare at Work Act 2005. The Regulations require employers to avoid entry into confined spaces where possible, and where entry is unavoidable, to carry out a risk assessment and implement a safe system of work.

The Risk Assessment for Confined Space Entry

A risk assessment for confined space entry must be carried out before any entry takes place. The risk assessment must identify the hazards present in the confined space, assess the level of risk, and specify the controls required to manage that risk. The key hazards to consider are:

Oxygen deficiency. The atmosphere in a confined space may be deficient in oxygen due to biological processes (such as the decomposition of organic matter in sewers), chemical reactions (such as the rusting of steel in a tank), or displacement by other gases. An atmosphere with less than 19.5% oxygen is considered oxygen-deficient and can cause loss of consciousness and death within minutes.

Toxic gases and vapours. Confined spaces may contain toxic gases including hydrogen sulphide (in sewers and drainage systems), carbon monoxide (from internal combustion engines or fires), and methane (in sewers and near landfills). Toxic gases can cause rapid incapacitation and death at concentrations that may not be detectable by smell.

Flammable gases and vapours. Methane and other flammable gases can accumulate in confined spaces and create an explosive atmosphere. Any ignition source, including electrical equipment, tools, or static electricity, can trigger an explosion.

Engulfment. In some confined spaces, there is a risk of engulfment by free-flowing solids such as grain, sand, or sludge. On construction sites, this hazard is most relevant in excavations and storage silos.

Restricted access and egress. The restricted access and egress of a confined space means that rescue is difficult and time-consuming. If a worker becomes incapacitated inside a confined space, the time available for rescue may be very short.

The Permit-to-Work System

A permit-to-work system is a formal control that requires written authorisation before entry into a confined space. The permit must specify the confined space to be entered, the work to be carried out, the hazards identified in the risk assessment, the controls required, the atmospheric testing results, the names of the entrants and the standby person, and the duration of the permit.

Atmospheric testing must be carried out immediately before entry and continuously during entry where there is a risk of atmospheric change. Testing must be carried out by a competent person using calibrated gas detection equipment.

Rescue Arrangements

Rescue arrangements must be in place before any entry into a confined space. The rescue arrangements must be specific to the confined space and must not rely on the emergency services as the primary means of rescue, because the time taken for the emergency services to arrive may be too long to prevent a fatality.

The rescue arrangements must include a trained standby person outside the confined space at all times during entry, rescue equipment appropriate to the confined space (including a harness and lifeline for the entrant where the geometry of the space permits), and a means of raising the alarm and summoning additional help if needed.

Conclusion

Confined space entry is one of the highest-risk activities on Irish construction sites. The risk assessment must be thorough, the permit-to-work system must be rigorously applied, and the rescue arrangements must be in place before any entry takes place. The consequences of inadequate preparation for confined space entry can be fatal, and multiple fatalities have occurred in Ireland when would-be rescuers have entered confined spaces without adequate preparation.