Confined spaces are potentially hazardous spaces. They are places that you could be trapped such as pipes, vaults, manholes, tunnels, silos, sewer, storage tanks, pits etc. Confined spaces may have hazards such as lack of breathable air, extreme temperatures, hazardous gases, dust or loose powders or liquids that might engulf you. Before entering you must know what the hazards are and how they can be prevented. You also need authorization before working in a confined space. Effective hazard warnings and barricades must be put in place to notify everyone of potential hazards and to restrict unauthorised entry. Rescue operations must be carried out only by trained and designated personnel.  This well designed OSHA standard confined space entry training will certify you competent to work in confined spaces. REGULATORY REFERENCE 29 CFR 1910.146 (OSHA’s standard)