CoatingsPro Magazine

JAN 2017

CoatingsPro offers an in-depth look at coatings based on case studies, successful business operation, new products, industry news, and the safe and profitable use of coatings and equipment.

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Page 22 of 116

22 JANUARY 2017 COATINGSPROMAG.COM Notes From the Blog Editor's Note: Looking for " in the field " information about the latest coating appli- cation techniques? We invite you to join the discussion. e following are excerpts from the NACE Corrosion Network's (NCN) and NACE Coatings Network's email-based discussion groups for corrosion profession- als, with more than 1,000 participants. e following excerpts have been selected for their potential interest to CoatingsPro readers. ey have been edited for clarity and length. Authors are kept anonymous for publication. Please be advised that the items are not peer-reviewed, and opinions and sug ges- tions are entirely those of the inquirers and respondents. CoatingsPro and NACE do not guarantee the accuracy of the technical solutions discussed. You' ll enjoy a variety of opinions in this practical information exchange forum. For information on how to subscribe to these free list servers, click on the "Community" link on the NACE Website: What Temperature to Coat Pipes Q: W hen deciding the coating system of a piping spool based on temperature, should we consider the design temperature or the operating temperature of the pipe in the piping line list? A: You have to consider the working/operating temperature of the piping, and then select the type of paint that is most suitable with that operating temperature. It should be higher than the operating of the pipe. A: Determining the temperature to use for the selection of a coating system can depend on the specific service the pipe will be placed in. e short version: It depends. e design temperature is often selected based on the design code used for the equipment, and it often has little to do with the actual minimum or maximum temperature that the item will see during its expected service life. As an example, for many years, American Society of Mechanical Engineers (ASME) defined a temperature range of -29° C (-20° F) to 343° C (650° F) for plain/mild carbon steel. ose were commonly listed as the design temperature range, as long as the process/operating temperature fell within that range — even though the service temperature might never vary beyond ambient conditions. e process design temperature may or may not be more realistic, depending upon what the process engineer used as a basis. Sometimes the temperature simply duplicated the design and had little to do with the actual process. e exception would be when the temperature variation affects the product or process. In all, you must consider both equipment design and process design. It is also important that minimum and maximum process values under upset conditions are considered. For a brand new process, it may be wise to choose temperatures nearer the design limits, because increasing or decreasing temperature is often the simplest way to increase the process output. And the operating temperature is likely to change with time. Leveling an Irregular Steel Deck Q: We have a steel deck on a new construction ferry, and the deck is constructed of 0.88-in. (2.24 cm) steel. is is new construction, and the deck is irregular. It has a lot of depres- sions in it, which collect rain water. Is there a compound that anyone knows of that could be used to level the deck? e deck would be subject to heav y vehicle traffic. A: You might want to look at products that are approved by the U.S. Nav y for f light deck areas. T hey are ty pically 100 percent solids w ith lots of fillers. At least one of your common coating suppliers sells them. You would not want to follow the actual installation instructions, as I am sure you do not want a surface as rough as they do — unless you are tr y ing to stop a jet plane. I believe they have a spray-on one, as well as the rolled-on ty pe. It w ill fill some depres- sions, if they are small, like pitting might be. But if you have large areas of depression, such as between support beams, I don't think an epox y w ill do it, since you are talking about possible inches of depth to fill! Keep in mind, no matter what anyone tells you, epox y is not as strong as steel. You could overlay it w ith a doubler, just make sure they do a full weld to attach it. I have seen that done on car ferries. However, paint w ill not fi x ever ything. T he reality is the deck may require additional support underneath it; has it been in ser vice? You mentioned new build — I am sur prised it is already bending, especially at 0.88 -in. (2.24 cm) steel! A nother option is a 100 percent solids urethane spray. You can build that as thick as you want, and it stands up well. It is expensive, and it requires special plural spray equipment. It Coating Temps, Deck Leveling, and Bleeding

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