Issue link: https://www.e-digitaleditions.com/i/1302781
November 2020 / 25 passageways for tank entry located on the silo's roof. Stored or previously stored material sitting on the roof is indicative of a spill or leak. If there is material pres- ent on the silo's roof, can you tell where the material is coming from? Connection points. You should familiarize yourself with how your storage system operates in relation to the equipment that interacts with the silo. Are the pneumatic conveying system fill lines, tubes, and elbows intact and in good working condition? Are the baghouses or dust collectors connected to the silo clean and functional? If there are gaskets present, do they need replacing? Inspecting the interior Body and roof. Examining an empty silo is also neces- sary for proper service and maintenance. With the silo empty, note the interior condition. If there are coatings on the interior, do the coatings appear to be intact? Are any areas of the coating peeling or are bare spots pres- ent? Check the top few feet of coating below the roof, as condensation will accumulate there and can some- times cause coating damage. Signs of coating damage edge to the dent's center. A general length-by-width measurement should be taken as well. If there is a dent present in the silo, do you know what caused it or when it occurred? Dents can originate externally from something impacting the silo or internally due to vacuum pressure from flow-related issues. Are there penetrations in the skirt for piping or wiring? Are those penetrations sealed completely against water? While insulation is used in many industries to help limit condensation, mold, and spoilage, insulated silos create challenges for inspection, as one side of the silo wall is typically hidden from view. If your silo has high-density spray foam, mineral wool, or fiberglass insulation, look for unsealed areas that might have let water in behind the insulation, as pockets of corrosion can occur in locations where water can become trapped. If there's a ladder system on your silo, what style is it? Does the ladder have a full cage or is it equipped with a safety-climb cable system, as shown in Figure 1? Look at the connection points between the ladder and the silo, checking for cracks or corrosion. If your silo has columns and cross-bracing, are there any sections missing? Oftentimes, installers will remove bracing to accommodate equipment and sometimes forget to reinstall the bracing. Make note of any columns and cross-bracing that are seemingly absent or damaged. Roof. Inspect the silo roof. If there is nonskid coat- ing or self-adhesive nonskid strips present, are they intact and functional? Are any present guardrails sturdy? Do all pressure-relieving devices operate as designed? Is there stored material present on the silo's roof? Often, there are pressure-relieving devices or FIGURE 1 Silo ladder systems exist to keep personnel safe when inspecting a silo but these ladder systems need to be inspected as well. WWW.POWDERBULK.COM/SUBSCRIBE