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Polibrid 700-Resin-A mixed with Polibrid 705-Catalyst-B, a low-VOC elastomeric polyurethane coating system. According to Penni Snodgrass, TIC's Marketing Manager, "The two- or three-coat epoxy coating systems have been the standard of the industry for the past 25 years. Recent additions to the coatings specifer's arsenal are the zinc-primed epoxy and the polyurethane interior coating systems. Metalized coatings, although also available for 25 years or so, are gaining popularity for the interiors of potable water storage tanks." She continues, "A properly applied 100 percent solids coating such as Polibrid/Polyclad has an anticipated service life that exceeds the life expectancy of the more traditional coatings. Although the materials cost for the 100 percent solids coatings are higher than the cost of the traditional interior coatings, the one-coat, multi-pass application process can result in a signifi- cant savings in labor costs." Alpine had to be extremely diligent with noise abatement during the project. In fact, one of the neighboring homes was only about 50 feet from the tank. Scaturro explains, "Sound attenuation was used to prevent noise from permeating into the housing neigh- borhood. We built temporary walls out of insulating blanket material around each piece of equipment that operated 24 hours a day, (the generator and the dehumidifier), to achieve a comfortable level of noise for the neighbors during the project." In addition, they also installed 10-mil poly sheeting around the entire seven-foot high chain link fencing surrounding the project area to help prevent noise and dust. The tank also stands in a residential neighborhood, so to Alpine Painting and Sandblasting, a family-owned business since 1974, with an extensive work history in tank refurbishing. Sam Scaturro, the operations manager and one of three brothers in the business that is headed by their father, Ben Sr. and their uncle, Steve, describes the scope of their business. "We are a very diverse company with a 30 member in-house crew, trained to work on many industrial scenarios and even commercial paint- ing. In order to work on the Chatham Tank project, each of the workers involved in the project had to have a New Jersey license and all supervisors had to have a supervisor license, which required more training." THE INTERIOR REMOVAL PROCESS The first step in the coating removal process was to bring in a welder to complete repairs before the abrasive blasting stage. The welder constructed a new roof vent, two new shell manholes, and rigged couplings in the top of the exterior of the tank. In addition, the welder removed any remaining spider rods, used to keep the interior of the tank round during construction. This process took about two weeks. The welder utilized a confined space procedure and a fire watch (a crewmember standing by with fire equipment) when welding the interior of the shell manways and removing the spider rods. water quality standards. The company even employs water testers to make sure that the users can't taste solvents in the water when the tanks are returned to service. So they elected to use a solvent- free coating on this project. In order to meet these standards, TIC specified the use of a one-coat material called Carboline With the crew in place, attention turned fully to coatings. New Jersey American Water Company has extremely high Once the welding repairs were complete, the abrasive blasting crew moved in. Because they would be working in a confined space, the crews used low-voltage explosion proof lighting and intrinsically safe motors specifically designed for use in confined spaces. Project specifications prepared by TIC required dehumidification during abrasive blasting and the use of heat to maintain proper steel surface temperature (40ºF minimum surface temperature, 25ºF ambient air temperature) during application of the coating. Alpine utilized a one million BTU Maxi heater, manufactured by Allmand Brothers, and a 5000 CFM Dryco dehumidifier to balance the interior air space to keep the appropriate atmospheric conditions in the tank interior. Scaturro explained, "The dehumidifying equipment allowed the crew to abrasive blast straight through and do the January 2009 J www.coatingspromag.com 87