Consulting-Specifying Engineer - July 2008 - (Page 49) Grounding and bonding practices for hazardous areas BY JEFF HEINEMANN, EIT, Electrical Engineer, and JARON VANDE HOEF, PE, Senior Project Engineer, Interstates Engineering, Sioux Center, Iowa Determining how to classify a hazardous area is a complex, multi-step process. Many factors influence classification, including fuel types within the atmosphere, the probability of the fuel being present and its concentration, temperature, humidity, barometric pressure, ventilation, and distance from the source. W ithin certain industrial facilities, there are areas of atmospheric conditions that may be inherently harmful to humans. If an ignition source is present within those areas, an explosion or fire can take place, causing damage to equipment, and injury or death to personnel. Flammable gases or vapors, combustible dusts, or ignitable fibers and flyings produce hazardous locations and represent distinctly different fire or explosion hazards. Such conditions exist in many places, but the ignitable or combustible mixtures are usually not present in quantities that can create a fire or explosion hazard. These ignitable and combustible materials must exist in concentrations high enough to warrant a hazardous location. In North America, a Class and Division system has been adopted for hazardous locations. Hazardous locations are divided into three Classes with each Class subdivided into two Divisions. The Classes are based on the type of hazard potential and the explosive nature of the materials, while Divisions are based on the probability of an explosion occurring. Hazardous locations Class I locations (defined by National Electric Code [NEC] Articles 500 and 501) have flammable gases or vapors (or have the potential for such gases or vapors) in concentrations within the atmosphere that may create the potential for fire or explosion. Class I subdivides into Division 1 and Division 2 categories based on the probability that a gas or vapor exists in the atmosphere. Division 1 areas are at a much higher risk, whereas Division 2 areas are at a lower risk but still constitute a hazard under abnormal operating conditions or catastrophic failure. Consulting-Specifying Engineer • JULY 2008 49
Table of Contents Feed for the Digital Edition of Consulting-Specifying Engineer - July 2008 Consulting-Specifying Engineer - July 2008 Contents Viewpoint Letters News M/E Roundtable 40 Under 40 Using Demand-Based Reset Strategies VFDs and Motors: Making the Right Match Grounding and Bonding Practices for Hazardous Areas Codes & Standards Case Study New Products Equipment Lifecycles Advertiser Index Green Space Consulting-Specifying Engineer - July 2008 Consulting-Specifying Engineer - July 2008 - Consulting-Specifying Engineer - July 2008 (Page Cover1) Consulting-Specifying Engineer - July 2008 - Consulting-Specifying Engineer - July 2008 (Page Cover2) Consulting-Specifying Engineer - July 2008 - Consulting-Specifying Engineer - July 2008 (Page 1) Consulting-Specifying Engineer - July 2008 - Consulting-Specifying Engineer - July 2008 (Page 2) Consulting-Specifying Engineer - July 2008 - Contents (Page 3) Consulting-Specifying Engineer - July 2008 - Contents (Page 4) Consulting-Specifying Engineer - July 2008 - Contents (Page 5) Consulting-Specifying Engineer - July 2008 - Contents (Page 6) Consulting-Specifying Engineer - July 2008 - Viewpoint (Page 7) Consulting-Specifying Engineer - July 2008 - Letters (Page 8) Consulting-Specifying Engineer - July 2008 - Letters (Page 9) Consulting-Specifying Engineer - July 2008 - News (Page 10) Consulting-Specifying Engineer - July 2008 - News (Page 11) Consulting-Specifying Engineer - July 2008 - M/E Roundtable (Page 12) Consulting-Specifying Engineer - July 2008 - M/E Roundtable (Page 13) Consulting-Specifying Engineer - July 2008 - M/E Roundtable (Page 14) Consulting-Specifying Engineer - July 2008 - M/E Roundtable (Page 15) Consulting-Specifying Engineer - July 2008 - M/E Roundtable (Page 16) Consulting-Specifying Engineer - July 2008 - 40 Under 40 (Page 17) Consulting-Specifying Engineer - July 2008 - 40 Under 40 (Page 18) Consulting-Specifying Engineer - July 2008 - 40 Under 40 (Page 19) Consulting-Specifying Engineer - July 2008 - 40 Under 40 (Page 20) Consulting-Specifying Engineer - July 2008 - 40 Under 40 (Page 21) Consulting-Specifying Engineer - July 2008 - 40 Under 40 (Page 22) Consulting-Specifying Engineer - July 2008 - 40 Under 40 (Page 23) Consulting-Specifying Engineer - July 2008 - 40 Under 40 (Page 24) Consulting-Specifying Engineer - July 2008 - 40 Under 40 (Page 25) Consulting-Specifying Engineer - July 2008 - 40 Under 40 (Page 26) Consulting-Specifying Engineer - July 2008 - 40 Under 40 (Page 27) Consulting-Specifying Engineer - July 2008 - 40 Under 40 (Page 28) Consulting-Specifying Engineer - July 2008 - 40 Under 40 (Page 29) Consulting-Specifying Engineer - July 2008 - 40 Under 40 (Page 30) Consulting-Specifying Engineer - July 2008 - 40 Under 40 (Page 31) Consulting-Specifying Engineer - July 2008 - 40 Under 40 (Page 32) Consulting-Specifying Engineer - July 2008 - Using Demand-Based Reset Strategies (Page 33) Consulting-Specifying Engineer - July 2008 - Using Demand-Based Reset Strategies (Page 34) Consulting-Specifying Engineer - July 2008 - Using Demand-Based Reset Strategies (Page 35) Consulting-Specifying Engineer - July 2008 - Using Demand-Based Reset Strategies (Page 36) Consulting-Specifying Engineer - July 2008 - Using Demand-Based Reset Strategies (Page 37) Consulting-Specifying Engineer - July 2008 - Using Demand-Based Reset Strategies (Page 38) Consulting-Specifying Engineer - July 2008 - Using Demand-Based Reset Strategies (Page 39) Consulting-Specifying Engineer - July 2008 - VFDs and Motors: Making the Right Match (Page 40) Consulting-Specifying Engineer - July 2008 - VFDs and Motors: Making the Right Match (Page 41) Consulting-Specifying Engineer - July 2008 - VFDs and Motors: Making the Right Match (Page 42) Consulting-Specifying Engineer - July 2008 - VFDs and Motors: Making the Right Match (Page 43) Consulting-Specifying Engineer - July 2008 - VFDs and Motors: Making the Right Match (Page 44) Consulting-Specifying Engineer - July 2008 - VFDs and Motors: Making the Right Match (Page 45) Consulting-Specifying Engineer - July 2008 - VFDs and Motors: Making the Right Match (Page 46) Consulting-Specifying Engineer - July 2008 - VFDs and Motors: Making the Right Match (Page 47) Consulting-Specifying Engineer - July 2008 - VFDs and Motors: Making the Right Match (Page 48) Consulting-Specifying Engineer - July 2008 - Grounding and Bonding Practices for Hazardous Areas (Page 49) Consulting-Specifying Engineer - July 2008 - Grounding and Bonding Practices for Hazardous Areas (Page 50) Consulting-Specifying Engineer - July 2008 - Grounding and Bonding Practices for Hazardous Areas (Page 51) Consulting-Specifying Engineer - July 2008 - Grounding and Bonding Practices for Hazardous Areas (Page 52) Consulting-Specifying Engineer - July 2008 - Grounding and Bonding Practices for Hazardous Areas (Page 52A) Consulting-Specifying Engineer - July 2008 - Grounding and Bonding Practices for Hazardous Areas (Page 52B) Consulting-Specifying Engineer - July 2008 - Grounding and Bonding Practices for Hazardous Areas (Page 53) Consulting-Specifying Engineer - July 2008 - Codes & Standards (Page 54) Consulting-Specifying Engineer - July 2008 - Codes & Standards (Page 55) Consulting-Specifying Engineer - July 2008 - Case Study (Page 56) Consulting-Specifying Engineer - July 2008 - Case Study (Page 57) Consulting-Specifying Engineer - July 2008 - New Products (Page 58) Consulting-Specifying Engineer - July 2008 - New Products (Page 59) Consulting-Specifying Engineer - July 2008 - Equipment Lifecycles (Page 60) Consulting-Specifying Engineer - July 2008 - Equipment Lifecycles (Page 61) Consulting-Specifying Engineer - July 2008 - Equipment Lifecycles (Page 62) Consulting-Specifying Engineer - July 2008 - Equipment Lifecycles (Page 63) Consulting-Specifying Engineer - July 2008 - Equipment Lifecycles (Page 64) Consulting-Specifying Engineer - July 2008 - Equipment Lifecycles (Page 65) Consulting-Specifying Engineer - July 2008 - Equipment Lifecycles (Page 66) Consulting-Specifying Engineer - July 2008 - Advertiser Index (Page 67) Consulting-Specifying Engineer - July 2008 - Green Space (Page 68) Consulting-Specifying Engineer - July 2008 - Green Space (Page Cover3) Consulting-Specifying Engineer - July 2008 - Green Space (Page Cover4)
For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.