In 1984 a rescuer was killed when an explosion occurred while he and his coworkers were attempting to cut a hole in a toluene tank to retrieve a worker who had died entering the confined space. The accident, captured on video, provides a graphic view of the hazards of performing hot work around confined spaces.
This incident was not unique. Fatalities from welding and hot work are often are associated with confined spaces and the areas adjacent to these confined spaces . The CSB has identified over 60 fatalities since 1990 due to explosions and fires from hot work activities on tanks, which are, of course, confined spaces. The CSB defines hot work as “work involving burning, welding, or a similar operation that is capable of initiating fires or explosions. Hot work also includes other activities with the potential to create a source of ignition such as cutting, brazing, grinding, and soldering.” CSB has released a Hot Work Safety Bulletinthat describes 11 incidents and has concluded that a critical factor in many of the accidents was the lack of continuous gas monitoring prior to or during the hot work activities. CSB noted that in many of the incidents there was inadequate monitoring not only in the confined spaces but also in the spaces adjacent to the confined space.
There are many organizations that have developed welding safety information. Each deals with a particular type of industry or specific work to be performed. For example, The National Fire Protection Association (NFPA) has several standards related to welding including NFPA 51B Standard for Fire Prevention during Welding, Cutting and Other Hot Work, NFPA 306http://www.nfpa.org/aboutthecodes/AboutTheCodes.asp?DocNum=306Standard for the Control of Gas Hazards on Vessels (for the marine industry), andhttp://www.nfpa.org/aboutthecodes/AboutTheCodes.asp?DocNum=326NFPA 326 Standard for the Safeguarding of Tanks and Containers for Entry, Cleaning and Repair . The American Welding Societyhttp://en.wikipedia.org/wiki/American_Welding_Society (AWS) publishes a standard, AWS Z49.1 Safety In Welding and Cutting and Allied Processes, as well as numerous fact sheets and welding safety information. The American Petroleum Institute (API) has numerous standards related to welding on petroleum tanks including API 653 Tank Inspection, Repair, Alteration, and Reconstruction, API RP 2009 Safe Welding and Cutting Practices in Refineries, Gasoline Plants, and Petrochemicals Plants and API Std 2015 Safe Entry and Cleaning of Petroleum Storage Tanks, Planning and Managing Tank Entry From Decommissioning Through Recommissioning. API also publishes a number of other standards for specific processes that may involve welding or other hot work. And Federal OSHA has several welding standards and has a health and safety topic page dedicated specifically to welding.
The inherent hazards associated with welding are complicated when welding is done in or around a confined space. The information available on welding safety is vast, but the connection between welding hazards and confined spaces must be made in order to decrease injuries and fatalities that occur from hot work.