Construction work sometimes takes place in confined spaces that aren’t always easy to enter, exit, or work in comfortably. They can include ventilation and exhaust ducts, sewers,tunnels, tanks, storage bins, manholes, pits, and silos. By definition, confined spaces are not actually designed for regular and continuous occupancy. They are usually designed to store a product, enclose materials or processes, or transport products or substances. Sometimes we need to enter these spaces to inspect them, perform maintenance,clean, or complete other tasks. Confined space hazards can include engulfment, suffocation, chemical exposure, electric shock, musculoskeletal injuries, and hazardous atmospheres. Other, simple hazards like heat stress and slips, trips, and falls are also common.
Working in confined spaces can be dangerous. The first consideration is analyzing the space. A confined space is a one that:
1. Is large enough and configured so that an employee can enter and do his or her work; and
2. Has limited or restricted means for entry or exit; and
3. Is not designed for continuous employee occupancy.
A Permit-Required confined space is a confined space that has any of the following characteristics:
1. It contains or has the potential to contain a hazardous atmosphere;
2. It contains a material that has the potential for engulfing a person who enters;
3. It has an internal configuration that could trap or asphyxiate a person, like a space with converging walls or a floor which slopes downward and tapers to a smaller cross-section; or
4. It contains any other recognized serious safety or health hazard.
Some of the most dangerous confined spaces have toxic, oxygen-deficient, or combustible atmospheres. These hazards can exist for a variety of reasons. Bad air circulation can allow combustible or toxic materials to accumulate. There may not be enough oxygen Inside the space to support life. The air may contain so much oxygen that a fire or explosion could occur if any ignition source is present.
Anytime you work in a confined space, follow the rules in the company’s confined space entry procedure. Don’t ever enter a confined space unless you have been trained to do so. Every confined space is different and each one requires careful evaluation to determine the hazards and the necessary controls and precautions. Constant air monitoring is critical and should be performed before and during entry. Remember, you can’t always see or smell toxic gases, and you can’t sense an atmosphere that is oxygen-deficient. Be aware of the risks.
In case of emergency. follow the rescue plan to the letter. Would-be rescuers frequently die in confined spaces.