6 Major Confined Space Hazards

Confined Space Hazards – Confine space poses lots of hazards which should be managed to prevent accidents. The confined space hazards should be properly managed before the commencement of any job inside the confine space.


What Is A Confined Space

Many workplaces contain areas that are considered “confined spaces” because while they are not necessarily designed for people, they are large enough for workers to enter and perform certain jobs. A confined space also has limited or restricted means for entry or exit and is not designed for continuous occupancy. Confined spaces include, but are not limited to, tanks, vessels, silos, storage bins, hoppers, vaults, pits, manholes, tunnels, equipment housings, ductwork, pipelines, etc.

OSHA uses the term “permit-required confined space” (permit space) to describe a confined space that has one or more of the following characteristics: contains or has the potential to contain a hazardous atmosphere; contains material that has the potential to engulf an entrant; has walls that converge inward or floors that slope downward and taper into a smaller area which could trap or asphyxiate an entrant; or contains any other recognized safety or health hazard, such as unguarded machinery, exposed live wires, or heat stress.

In this article, we will highlight main confined space hazards.

Confined Space Hazards

  1. Toxic Atmosphere

Toxic atmosphere occurs due to the presence of hazardous substances in the surrounding air. It may cause various acute effects, including impairment of judgement, unconsciousness and death. A toxic atmosphere may occur due to the presence or ingress of hazardous substances.

2. Oxygen Deficiency

Oxygen deficiency could occur due to
–    Displacement of air by another gas like carbon dioxide
–    Various biological processes or chemical reactions (such as rotting of organic matter, rusting of metals, burning, etc)
–    Absorption of air onto steel surfaces, especially where these are damp.

3. Oxygen Enrichment

An excess of oxygen, in the presence of combustible materials, results in an increased risk of fire and explosion. Some materials, which do not burn in air, may burn vigorously or even spontaneously in an enriched oxygen atmosphere.

4. Flammable Atmospheres

A flammable atmosphere presents a risk of fire or explosion the same way as oxygen enrichment. Such an atmosphere can arise from the presence in the confined space of flammable liquids or gases or of a suspension of combustible dust in air.

5. Flowing Liquid or Free Flowing Solids

Liquids or solids can flow into the confined space causing drowning, suffocation, burns and other injuries.  Solids in powder form may also be disturbed in a confined space resulting in an asphyxiating atmosphere.

6. Excessive Heat

The enclosed nature of a confined space can increase the risk of heat stroke or collapse from heat stress, if conditions are excessively hot. The risk may be exacerbated by the wearing of personal protective equipment or by lack of ventilation


Confined Space Hazard Solution

Confined spaces may be encountered in virtually any occupation; therefore, their recognition is the first step in preventing fatalities. Since deaths in confined spaces often occur because the atmosphere is oxygen-deficient, toxic or combustible, confined spaces that contain or have the potential to contain a serious atmospheric hazard should be classified as Permit-required confined spaces and should be tested prior to entry and continually monitored. The following references aid in recognizing and evaluating hazards and possible solutions related to confined spaces.


Further Reading

Type of fire extinguishing agent that should not be used in a confine space

Confine space rescue plan

Confine space entry hoist

Confine space entry procedures that works

Confined space atmospheric test