West Palm Beach, FL (PRWEB) January 4, 2006
The Nation Fire and Protection Agency's 300 codes and standards influence every building, process, service, design, and installation in the United States. NFPA 68, "Guide for Venting of Deflagrations" is the standard used for explosion venting in North America. The document is currently under revision as trends in the explosion protection industry are continuously changing.
CV Technology is among the many companies that sit on the Technical Committee on Explosion Protection Systems for the NFPA. The Florida based corporation is helping to formulate the latest explosion venting methodology that, upon adoption, will become available with the next edition of NFPA 68. CV Technology is an industry leader in explosion protection and mitigation strategy and devices.
According to the NFPA 68, the current definition of an explosion vent is "An opening in an enclosure to relieve the developing pressure from a deflagration." Other then the abstract, an "explosion vent" can be a physical, passive device requiring little if any routine maintenance. Explosion vents do not prevent an occurrence. Explosion venting is a damage limiting technique involving strategic placement of these venting devices.
Bill Stevenson, VP Engineering for CV Technology, provides the following analogy, "Think of an explosion vent as a window in a room. If an explosion were to occur in the room, the window would blow out first." Stevenson continues to explain, "If the window is large enough and weak enough relative to the walls, floor, and ceiling, the room would still be standing after the blast."
It should be easy to appreciate the elegance of such a simple and effective solution to the problem of providing explosion protection. It is no wonder that explosion venting is so frequently chosen. While simple in concept, it is quite complex in implementation. There are some pitfalls and even unknown factors involving explosion venting that can move from safe protection to complete disaster.
So what are the pitfalls that render this seemingly simple concept so profoundly complex? Well it starts and ends with trying to determine the appropriate size and placement of an explosion venting device. For many years it has been typical that vent sizing was quite conservative. Bigger would be better, or at least safer, or so the thinking went. Unfortunately, there are problems with that approach. If the sizing calculation method results in larger vent areas than can be fit onto the enclosure there is a dilemma.
Stevenson explains, "In a situation where a duct is used to direct a flameball outside of building, a too low pressure discharge from the vent into the duct can result in a large quantity of unburned, suspended dust entering the duct where ignition would result in a far larger and more severe secondary explosion."
In other words, bigger is not necessarily better. There are many vent size modifiers that have to be considered including; ducts, length to diameter ratios, and the properties of combustible materials. Although not yet finalized, the latest edition of the NFPA 68 is expected to contain revised standards for vent sizing. The science of explosion protection, in general, is evolving with more testing and better communication providing a foundation for constant learning and improved safety.
CV Technology combines a legacy of experienced explosion consulting with revolutionary and completely unique explosion prevention and explosion protection technologies to specialize in the prevention, protection, and elimination of dust explosion hazards in all industries which process powders and dry bulk materials.
CV TECHNOLOGY, INC
2580 Metrocentre Boulevard
West Palm Beach, FL 33407
Phone: (561) 683 - 1200
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