Identifying confined space hazards is very important for almost all construction sites. The confined space entry standards as defined by OSHA, for General Industry and Construction are actively enforced by OSHA. There’s good reason. Confined space incidents have risen in both industries, but is amplified in Construction. Proper training, consistent inspection, documentation and preparation of a safety and rescue plan all are required under OSHA 29 CFR 1910.146 and OSHA 29 CFR 1910.146 Subpart AA.
Identifying Confined Space Hazards as Inherent or Induced Hazards
There are two types of hazards encountered in confined work spaces – inherent and induced. Inherent hazards are related to equipment and the interactions of working with them. Identifying inherent confined space hazards is based around the observation of operations and include hazards such as:
- shock or burn from high voltage electrical equipment
- exposure to radiation generated by certain equipment
- defectively designed equipment
- lack of protective features such as grounding for non-current-carrying conductive parts
- high or low temperatures
- high noise levels
- high-pressure equipment that may rupture.
- Inherent hazards cannot be eliminated from the equipment without affecting their operation, so these hazards must be used employing hazard control methods.
Induced hazards are those caused by incorrect decisions or actions during the construction process. Identifying confined space entry hazards involvingf induced hazards include:
- physical arrangements that might cause accidental contact by a worker with electrical energy sources
- lack of oxygen in areas like the bottom of pits or shafts
- omission of protective features
- lack of safe structural strength of the workspace
- flammable atmospheres such as those where volatile gases may be present.
Identifying confined space hazards may involve both inherent and induced hazards. Examples of such hazardous environments include:
- Vaults in which the atmosphere may be or become oxygen-deficient.
- Electrical vaults which may become filled with explosive gases such as from propane, or toxic fumes that can build-up in a limited atmosphere from welding and soldering in a confined space.
- Electrical shock can occur when working in any confined space with power tools, line cords, and similar equipment, where the contractor has not provided an approved grounding system, ground-fault circuit interrupters, or low-voltage systems.
- In a workspace where purging agents such as nitrogen or argon are being used in an adjacent area, the fumes may displace the oxygen in a vault to the point where workers could suffer immediate asphyxiation.
- Condenser pits are a type of confined space encountered during the construction of nuclear power plants which are fairly large, so that the potential for the hazards associated with a confined workspace may be overlooked. Toxic fumes and gases can accumulate in these areas from the use of argon, freon, and other inert gases, creating oxygen-deficient atmospheres for workers. Another hazard in this type of workspace is caused by workers above accidentally dropping equipment, tools, or other materials into the pit.
- Pipe assemblies are another type of confined space common in construction. Identifying confined space hazards of this type, can involve other types of work spaces, such as oxygen-deficient atmospheres caused by purging with argon or other inert gases. They may contain ungrounded electrical equipment, also. They can also be very restricted spaces where there is little room for workers to move around or find a comfortable position to perform their work. Also, where bends occur in pipes communication can be cut off, and getting a worker out of the area can be extremely difficult. The heat within a pipe may cause workers to suffer heat prostration, as well.
- The same types of hazards are encountered working within ventilation ducts as within pipes. Identifying confined space hazards in narrow spaces are characterized by many bends restricting movement and communication, They can contain toxic or oxygen-deficient atmospheres. In some cases electrical shock, and extreme heat all can occur within this type of space.
- Tanks used for storage of water, chemicals, or other materials often require entry for cleaning or repairs. Identifying confined space hazards in these spaces can include heat, oxygen-deficient atmospheres and electrical shock. They may also contain fall hazards from climbing high ladders on the walls of a tank.
- Manholes are common on construction sites. Manhole covers are sometimes removed and not replaced, or not provided at all, making it a dangerous trap where a worker may fall. Identifying confined space hazards here can many time can be easily fixed.
Other hazardous confined work spaces include sumps, containment cavities, electrical transformers, and heat sinks, all of which carry the risks of the same inherent and induced hazards associated with the spaces described above. Identifying confined space hazards in these potentially hazardous environments is critical
Awareness of the hazards found in these types of confined entry work spaces is an important step in the prevention of injuries and fatalities caused by these hazards.