What is a confined space?
It is a place of difficult access with limited means to enter and exit that are accessed usually by means such as ladders, iron steps, polypropylene manhole steps or by lifting systems with harness. They do not have a natural ventilation so the atmosphere is deficient in oxygen and accumulate polluting, toxic and flammable gases.
Types of Confined Spaces
- Tanks and wells.
- Basements and lofts.
- Pits, tunnels.
- Excavations greater than 4 feet-depth.
Works in confined spaces
- Oxygen shortage: In a confined space, there is a given amount of oxygen, respiration increases the carbon dioxide. When oxygen decreases to less than 19.5%, the atmosphere is deficient in oxygen and endangers the life of the occupants.
- Risk of explosion: Fire and explosions are serious hazards in confined spaces. On the other hand, flammable gases or vapors may be present in previous cargoes, tank linings or welding gases. These gases may be ignited by faulty electrical equipment, static electricity, welding sparks or cigarettes.
- Toxic gases in the air from materials previously stored in tanks or because of coatings or cleaning solvents. The often cannot be seen and cannot be smelled and irritate the respiratory or nervous system and can cut off the flow of oxygen.
Accidents caused by inhalation of gases in confined spaces
There have been a lot of accidents related to the inhalation of toxic gases in confined spaces like sewers, septic tanks or register wells. Most of them have not taken the necessary protocol measures before entering these spaces, where after a previous analysis of the gases contained inside, the space should be adequately ventilated to release the area of toxic gases or even unpleasant odors.
One of the most polluting gases is hydrogen sulfide, a very toxic gas, which still causes fewer deaths than other gases, such as hydrocyanic, which is detected quickly due to its bad smell. However, from certain concentrations, it numbs your sense of smell and the affected person no longer perceives the stench. If concentration continues to rise, death can occur. As its density is greater than air, it accumulates in places like wells or septic tanks, where it has caused fatalities. Often there are several affected, a first victim falls unconscious and then faint those who try to rescue without the necessary protective equipment.
As an example, in Spain there were 33 deaths between 2000 and 2007 related to accidents due to falls or inhalation of toxic gases in septic tanks.
Ventilation of confined spaces
Ventilation of confined spaces, perhaps the most intuitive control technique, is a fundamental measure of prevention, both for the relative simplicity of its application and for its effectiveness. This is so, even if indoor environmental assessments give satisfactory results, since there is a possibility that:
- There are unexpected dangerous contaminants hard to detect with standard measuring instruments.
- The environment degrades so quickly that the measuring devices cannot alert sufficiently in advance.
- Errors in measurement due to improper handling of measuring instruments, malfunctioning, incorrect methodologies, etc.
In IVERNA we have specific ventilation technology for urban sanitation networks with equipment such as Pozovent, a versatile equipment running by electricity or gasoline, that connects directly to the shape of the well; CVG- Spark-proof (for explosive gases, methane gas) odor extraction and ventilation booth for different flows and our Motovent with gasoline engine, also for extraction and ventilation of wells.
To neutralize the negative effects of odors coming from holding tanks, specially: inspection chambers, sewage pumping stations and septic tanks, we have our activated carbon filter, Sugarpod.
Find out more about our products here.