How to Avoid Asphyxiation Due To Hazard in Pits

Posted On: July 30, 2018

Construction workers are exposed to some of the most dangerous health hazards. This includes dangers that come with working in confined spaces one of which is asphyxiation.

Under normal conditions, we can breathe air that is made up of at least 20.9% of oxygen. When that amount drops by even 1%, breathing is a challenge. Overweight or muscular individuals may have more difficulty breathing under such conditions and can get disoriented faster. When the oxygen level drops to less than 10 or 12%, judgment is impaired and the lips turn blue. Death is imminent in 8 minutes if the level drops to 6 or 8% depending on the health, work environment, and physical activity level of the confined space worker.

What are confined spaces?

According to OSHA, a confined space:

  • Is big enough for a worker to enter completely and completed assigned tasks.
  • Is not designed or suitable for long-term/continuous occupancy.
  • Is restricted in terms of exits/entryways.

These spaces have limited oxygen even if these are large enough to accommodate workers. Some of them require permits since the threat of engulfment or asphyxiation is imminent. This includes confined spaces or pits that have floors that taper to smaller points or are sloped. Besides pits, these workspaces include tanks, vaults, storage bins, storage vessels etc.

How to prevent asphyxiation in confined spaces

Permit-required confined spaces and permit spaces refer to workplace that meet the abovementioned definition as proposed by OSHA. This includes the health and safety concerns that are particular to them. However, asphyxiation is the most common hazard in spaces that have limited space. The good news is that the risks can reduced with a few precautions. Here are a few of them:

Purge the confined space before entry

Before workers are allowed to enter a confined space, it should be purged of all sludge and other deposits that can prove hazardous. The deposits can give off toxic vapors, dust or fumes that can not only interrupt operations, but can also cause serious illnesses. If steam cleaning is used for the purge, supervisors should allow the space to cool down first to ensure it is safe to work in.

Check entrance size

Check to see if the entrance of the confined space is large enough for workers to work in. If they can enter with the protective gear and equipment they need without obstruction, the space is safe for limited occupation. Remember, they will need that gear and equipment not only for their job, but to handle emergencies as well. If the entrance is too narrow for this to be possible, workers should be equipped with air-line breathing apparatus rather than self-contained ones which are bulkier. The larger the equipment, the harder it will be for them to enter/work/exit the space.

Ensure adequate ventilation

Since confined spaces are not ventilated, measures should be taken to ensure workers don’t suffocate. This can be done if the number of openings is increased but mechanical measures may be needed for a fresh air supply. By air supply we don’t mean pure oxygen. Fresh oxygen can increase the risks of a fire or explosion from the smallest spark. Normal fresh air should be piped in especially if the space contains compressed gas or burning equipment is used. Engine exhaust can cause an explosion if the workspace has high enough oxygen content.

Test the air

Before workers are allowed to work in a confined space, its air quality should be tested. This will show whether the air is free of toxic/flammable gases and if it has enough oxygen content that is fit to breathe. The test should be carried out by a competent individual with equipment that can be calibrated. If the risk assessment reveals that the conditions of the space may change with time or during the course of the work, the air quality should be tested continuously.

Confined Space Entry Training

Confined spaces in the construction and general industries are inherently hazardous to work in and are therefore not mean for continuous occupation. To understand the safety risks of working in such spaces, workers have to get certified according to OSHA requirements The Confined Space Entry Training course from is designed for professional and entry level workers who need to work in confined spaces. This includes silos, pits, pipelines, bins, manholes, vaults and other spaces that fit OSHA’s description for such work spaces. Sign up today.

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