A confined space is a partially or totally closed structure that has not been designed to be permanently occupied by workers. Operating inside (confined space entry) must remain exceptional: during their construction, their servicing (particularly while cleaning) or their maintenance (periodical checking, repair).
- Waste water treatment : chlorination, ozonation
- Crawl spaces, sewers, drains, pipes
- Mines, long and thin galleries
- Cisterns, tanks, containers
- Wells, sinks, pits, silos and cellars
Confined space entry
Major confined space hazards
The majority of accidents – oftentimes severe or lethal – that occur during confined space entries are due to oxygen deficiency, presence of toxic gas or vapor and explosion or fire. Thus these are the first hazards to monitor while forecasting an intervention on this kind of site.
- Asphyxia, anoxiaor hypoxia : temporary or definitive lack of oxygen that can lead to death
- Intoxication: intoxication is due to inhalation or absorption of a toxic substance (hydrogen sulfide, carbon monoxide, hydrogen cyanide) which can cause death
- Explosion and fire: presence of flammable combustible gas (natural gas, butane, propane, hydrocarbon vapors) or dust can trigger fire and explosion
Risk prevention for confined space entry
It is highly recommended to organize in advance the practicability and the required prevention means before any confined space entry. In addition to classic PPE (helmet, gloves, safety footwear, boots…) it is prescribed to use a 4 gas monitor for confined space (combustible gas, oxygen deficiency, carbon monoxide and hydrogen sulfide) and to have a self-rescuer respirator for emergency evacuation…
Confined space training
Any worker - such as construction workers, HVAC technicians or firefighters – who can potentially work in a confined space environment need to receive proper confined space training, depending on the risk level of their activity.
Confined space awareness courses are elaborated so that learners understand more about safe work practices, suitable gas monitoring equipment use, and to teach what the regulations sates regarding work safety.
Thanks to local training (like OSHA confined space training in the USA, CATEC® training in France, and different confined space certification in other territories), workers evolving in these environments have knowledge of their legal responsibilities under confined spaces regulations and other related legislation. They also understand how to prevent and react to various risks. Once trained, workers are aware of the dangers of working in confined spaces and understand the importance of implementing appropriate control measures and necessary emergency procedures.
Portable gas detectors and area gas monitors for confined spaces
The most commonly used confined space air monitor is the 4 gas confined space meter which simultaneously monitors combustible gas (methane), oxygen (O2), carbon monoxide (CO) and hydrogen sulfide (H2S).
Respiratory protection for confined space entry
For emergency evacuation, the self-rescuer mask is a must have PPE. It is also possible to equip yourself with an SCBA to operate in confined spaces for a longer time.