Confined Space Entry Monitoring: A Complete Guide to Safer Workplace Operations

Working in a confined space can present hazards that are not always visible to workers. A tank, vessel, manhole, pit, silo, chamber, or other enclosed area may have limited ventilation and can contain dangerous gases, vapours, fumes, or other hazards. Conditions can also change while work is taking place.

For this reason, confined space entry monitoring is an important part of a well-planned confined-space safety programme. Monitoring helps responsible personnel understand conditions inside a space and identify changes that may require workers to stop work or leave the area.

What Is a Confined Space?

A confined space is generally an enclosed or partially enclosed area that may present particular risks to people who enter it. Examples can include tanks, manholes, silos, pits, vessels, pipes, chambers, and similar structures.

The exact legal definition varies according to the jurisdiction. In Singapore, for example, the Workplace Safety and Health (Confined Spaces) Regulations 2009 cover confined spaces and include requirements relating to entry permits, monitoring, atmospheric testing, training, attendants, and rescue operations.

Why Confined Spaces Can Be Dangerous

One of the biggest concerns with confined spaces is that hazardous conditions may not be obvious from outside.

The atmosphere inside a space can contain insufficient oxygen, combustible gases or vapours, or toxic substances. Some hazardous gases may also be difficult or impossible for a person to detect using their senses.

What Is Confined Space Entry Monitoring?

Confined space entry monitoring involves checking conditions associated with a confined-space operation before and, where required, during entry.

Atmospheric monitoring is an important component. Depending on the hazards identified, monitoring may involve checking oxygen concentration, combustible gases or vapours, and specific toxic gases or other contaminants.

Monitoring can involve portable instruments, personal gas detectors, remote monitoring equipment, or other suitable systems. The equipment selected should match the hazards identified for the particular space.

The Importance of Atmospheric Monitoring

Atmospheric conditions are a major consideration in many confined-space operations.

Before entry, appropriate testing should be performed to determine whether the conditions are suitable for the planned work. The specific testing process should be based on the hazards identified during the assessment.

OSHA guidance, for example, describes testing for oxygen first, followed by combustible gases and vapours and then toxic gases and vapours in relevant permit-space operations. It also recognizes that atmospheric hazards may not be evenly distributed throughout a confined space.

Conclusion

Confined space entry monitoring is an important element of protecting workers during confined-space operations. Atmospheric conditions can change, hazards may not be visible, and a previously safe condition does not necessarily remain safe throughout the entire job.

Effective monitoring begins with proper planning. Organizations need to understand the hazards of the space, select appropriate equipment, establish entry procedures, train workers, maintain communication, and prepare for emergencies.