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COATINGSPRO NOVEMBER 2014 61 Luckily, Longmore had experience with coating that would do this type of job. "Our product, you literally spray it, and a few hours later you can fll the torus with water," he said. Coatings Mixology Tin Film Technology makes a sprayable coating product called BIO-DUR that seemed right for the job. It's a blend of liquid epoxy polymer and curing agents that's solvent-free and uses Kevlar fbers to reinforce and manage viscosity, which means it can be applied easily under water. Tere was just one problem: BIO-DUR was light grey, and the client wanted blue. But this color choice ended up giving Longmore a chance to innovate, with amazing results. "Plural equipment today — the component airless spray — is pretty reliable," he said. "But you have to heat it so it sprays, because it's 100 percent solvent- free, so you have to heat it to make it thin. But once you mix it together, you have about 5 minutes to apply it, because without heat it hardens up too quickly. So you keep the components separate all the way until the spray gun." But there was no way to know if something goes wrong with the mixture, Longmore said, and that's where his innovation comes in. "In the old days, if you had a problem, the operator wouldn't know what was wrong," he said. "In the meantime, he's applied 2,000–3,000 square feet (186–279 m²) of coating that's never cured, because he didn't know what the problem was." So Longmore developed BIO-DUR 560 Blue, a 1/1 volume ratio epoxy. "Te epoxy base is ink blue and the curing agent is snow white, so when mixed in the application equipment, the coating is a light blue," he said. "As the guy was spraying, if it begins to get very light or very dark, he knows it's a problem, and he can stop spraying right then before damage is done." Longmore used the mix on a few other jobs before this one, so he had a chance to refne it. But there were still complica- tions. "Te coating material had to be made under supervision, because we're under strict QA /QC from another company," he said of the quality assurance/quality control. Te coating was made in July 2013, months before the job The crew wore carbon cartridge respiratory protection, impervious protective clothing and gloves, and splash-proof goggles. And the coatings were safe too. They were inspected and sealed before arriving at the site. JOB AT A GLANCE PROJECT: Re-line a pressure vessel under the nuclear reactor in a North American nuclear power plant. COATINGS CONTRACTOR: Williams Specialty Services 100 Crescent Centre Parkway, Suite 1240 Tucker, GA 30084 (866) 851-4077 www.wisgrp.com SIZE OF CONTRACTOR: About 700 SIZE OF CREW: 40 PRIME CLIENT: A North American nuclear power plant that wishes to remain unnamed SUBSTRATE: Internal carbon steel surface of a large pressure vessel CONDITION OF SUBSTRATE: Used; the substrate had remains of worn inorganic zinc-rich coating with some rust and rust staining present. SIZE OF JOB: 32,000 sq. ft. (2,973 m²) DURATION: Less than one week UNUSUAL FACTORS/CHALLENGES: » Pumping equipment had to be situated outside the facility, so coating was applied using heated, plural component airless spray fed by hose packs over 400 feet (122 m) long. » Spraying area accessible only through two 54-inch (137 cm) manholes, so a solvent-free coating was used. » All material had to be quality assurance/quality controlled (QA/QC) certified months before use. Security had to be present during job; coating had to be inspected and delivered in secure trucks. » BIO-DUR 560 Blue 1/1 volume ratio epoxy coating was specifically devel- oped by Thin Film Technology for nuclear service. The epoxy base is ink blue and the curing agent is snow white; when mixed in the application equipment the coating is a light blue, which ensures that the applicator is instantly aware of any "off-ratio" problem by a change in color. MATERIALS/PROCESSES: » Used coating that was supplied in 55-gallon (208 L) open-head drums, which dispensed automatically through large rams into heated auto-level reservoirs on the plural pump equipment » Stripe-coated sharp edges and wells » Spray-applied the coating in one pass at a minimum of 30 mils (762 microns) thickness using custom-manufactured spray equipment SAFETY CONSIDERATIONS: » Almost no volatile organic compounds (VOCs) were emitted by the coating, but carbon cartridge respiratory protection was used to guard against particulates. » Impervious protective clothing and gloves were used to protect against both coating contact and possible slight background radiation. » Splash-proof goggles were used by all applicators.