Issue link: https://www.e-digitaleditions.com/i/1192126
32 I ICT TODAY Because many of the criteria are difficult to measure accurately, this leads some designers to use their own experience and judgement. With that in mind, it is important to rate the described area with the highest rating in all categories (M 3 I 3 C 3 E 3 ) (Figure 2) for the following reasons: • Mechanical: The area is subject to constant vibration while the furnace is in operation with susceptibility to shock each time the furnace is loaded. The entire process area requires the use of heavy mobile equipment. • Ingress: Dust is always present while the factory is in operation. Visual inspection of existing electrical enclosures and equipment indicate that the dust mounds atop any upward facing surface. The dust is metallic in nature and therefore an enemy to electronic equipment. • Climatic/Chemical: The ambient and radiant heat created from the process, combined especially with the summer heat and humidity, creates a severe envi- ronment. The transition from the environmentally controlled operator control room and the surrounding factory floor must be considered when planning pathways and media since this is a prime location for water problems due to condensate. Industrial networks are designed to control time sensitive processes that, if compromised, can have a significant negative impact on both safety and production. Increased Environmental Severity Office Mechanical • Shock • Vibration M 1 M 2 M 3 I 1 I 2 I 3 C 1 C 2 C 3 E 1 E 2 E 3 Ingress • Water • Dust Climatic Chemical Electromagnetic Industrial FIGURE 2: This chart aptly depicts the MICE rating criteria that are detailed further in the TIA-1005-A standard. • Electromagnetic: With an 8 MW electric arc furnace as the primary piece of equipment in this operation, it is inevitable that there will be intense electromag- netic fields present. Combine this with the metallic dust suspended in the air (and a blanket of it covering everything else), and the resulting EMI potential is significant. Now that the information harvesting process is com- pleted, the designer can proceed to media selection. The compilation of knowledge acquired through information harvesting helps to facilitate the selection of appropriate pathways, components, and media with far greater certainty of long term functional success. The media selection results based on the information harvesting process is as follows: