Kst to cst11/26/2022 ![]() ![]() While “explosion” data can be found for many typical dusts, companies are encouraged to test a sample of their specific dust for its explosive characteristics because the existing data is too general in nature. ![]() St 3 - K St value greater than 300 bar-m/sec St 2 - K St value between 201 and 300 bar-m/sec St 1 - K St value less than/or equal to 200 bar-m/sec and greater than 0 The St class is based on the K St value as follows: The Explosion Severity test will tell you what “St Class” your sample falls within, which is helpful in guiding service providers as they analyze your equipment and your facility. In fact, some of the most famous dust explosions case studies come from St 1 class dusts: such as the Imperial Sugar explosion in 2008 in Georgia, and (historically) the Washburn A Mill explosion in 1876. are typically considered St 1 class dusts. Even a St1 dust generates sufficient power to cause a flash fire, compromise containment on a piece of equipment, or blow out the walls of a building. All other dusts have an explosion hazard. A material that has zero risk (K st = 0) of explosion is an St0 dust. The level of explosion violence increases with the class number. More simply put, these data values tell you how much pressure an explosion will generate and how fast the explosion will travel.Ĭombustible dusts are ranked into one of four classes St0, St1, St2, St3. The K St value determines the normalized rate of pressure rise of a combustible dust and the P max value measures the maximum explosion overpressure generated in the test chamber. To quantify the severity of a dust explosion. The explosion severity test generates the K st and P max values which are the explosive properties measured in the laboratory The buildup of even very small amounts of dust can cause serious damage if an event were to occur. Housekeeping is very important, especially in facilities that generate dust within their processes. The buildup of even a very small amount of dust can cause serious damage.ĭust can collect on surfaces such as rafters, roofs, suspended ceilings, ducts, crevices, dust collectors, and other History equipment. A secondary (often more powerful) explosion can occur when dust accumulated on floors or other surfaces is disrupted and lifted into the air and ignited by the primary explosion. A primary dust explosion can occur when a dust suspended within a container, room or piece of equipment is ignited. ![]() When the dust is disturbed, there is the potential for a serious explosion to occur under the right circumstances. Unlike a dust fire, a dust explosion requires two additional factors such as confinement and dispersion. Removing any one of these elements of the classic fire triangle eliminates the possibility of a fire. Like all fires, a dust fire occurs when fuel (the combustible dust) is exposed to heat (an ignition source) in the presence of oxygen (air) as demonstrated below: Essentially, any workplace that generates or handles dust is potentially at risk. The buildup of dried residue from the processing of wet materials also can generate dusts. OSHA defines combustible dust as "a solid material composed of distinct particles or pieces, regardless of size, shape, or chemical composition, which presents a fire or deflagration hazard when suspended in air or some other oxidizing medium over a range of concentrations." fiberglass, carbon, graphite, etc.)Ĭombustible dust is a particulate solid, traditionally defined as 420 - 500 µm or smaller that presents a fire or deflagration hazard when suspended in air or oxidizing atmosphere over a range of concentrations, regardless of particle morphology. Some nonmetallic inorganic materials (i.e.Per the Canadian Centre for Occupational Health and Safety: Essentially, a combustible dust is any fine material that has the ability to catch fire and explode when mixed with air. Recognized as an industry expert, his work has appeared in numerous journals and publications, has been a featured presenter at more than 23 conferences, serves on the NFPA 664, 61, 484 and 654 technical committees, the ASTM E27.05 technical committee and sits on the editorial advisory board for Powder & Bulk Solids and Journal of Loss Prevention. How to use Kst and Pmax Tests EffectivelyĪshok Ghose Dastidar, PhD MBA is a specialist in the areas of Chemical Process Hazards Analysis, Flammable Dusts, Liquids & Vapors Explosion and Combustion Hazards Analysis and Testing and Electrostatic Hazards Analysis.» Click here for CST to Local Time Conversion. » Click here for Korea Time to Local Time Conversion. ![]()
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