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Posted by Bob Peterson on 19 April, 2001 - 11:22 am
Just out of curiousity, is there any standard for tropicalization? Even a generally agreed upon method? A client has received a request that a control panel be tropicalized. I seem to recall years ago having to get specially coated circuit boards for such an application. I think we even sent boards out for coating that the manufacturer did not offer that way. Any advice?

Posted by jmGiraud on 19 April, 2001 - 6:45 pm
About special anti fungus coating, yes there was standards. Western european countries had to apply the standard. Is there something in the IEC ? I have no recollection.

Posted by Anthony Kerstens on 20 April, 2001 - 9:30 am
Does this just mean protecting it from heat and humidity??? Look at your environment and specify the appropriate enclosure. Do a heat calculation to size an air conditioner or heat exchanger. You should be able to get all the information and calculations you need from an enclosure supplier. Anthony Kerstens P.Eng.

Posted by Bob Peterson on 20 April, 2001 - 2:22 pm
Usually tropicalization refers to the components themselves rather then enclosure. Tropicalization of the PCBs themselves is to prevent water ingress and fungus growth on the PCBs. You can buy devices such as transformers and motors (even UPS's) that have been "tropicalized". Modicon used to offer a conformal coating for its I/O modules and PLCs.

Posted by Vitor Finkel on 20 April, 2001 - 2:23 pm
Heat and humidity are so often coupled with biological "hazards" to electrical/electronic equipment. Sometime ago I heard about tropicalized contactors. They were easy to recognize, since their body was made with white injected "plastic", instead of the mfg. std brown. I heard they mixed anti-bacterial chemicals in the "plastic" formula to prevent microorganisms growth to attack the very substance used for the contactors body/insulation. I also heard about Printed Circuit Boards to be covered by a translucent plastic coat ( dipped into a polymerizing mixture ), to the same effects. In a different application, tropicalization meant every access hole to the equipment, no matter how small, was covered with a fine mesh screen, to avoid penetration of bugs/ants/flying insects. I don't know about any standards, except vendor's specs about Tropicalization. Vitor Finkel P.O. Box 16061 Tel (+55) 21 285-5641 22221.971 Rio de Janeiro Brazil Fax (+55) 21 205-3339

Posted by Ramer-1, Carl on 20 April, 2001 - 2:38 pm
You may want to check out some vendors/suppliers using a Web search on "conformal coating". One such vendor follows, their Web page quoted because it identifies Mil and ANSI specifications that may also be helpful. From " 1-800-722-1444 Parylene Conformal Coating Specialists Circuit Boards, Keypads, Catheters, Medical Tubing, Hybrids, Integrated Circuits,Transducers, Sensors, Cores, Bobbins, Magnets... Mil-I-46058C, Type XY ANSI/IPC- A-610B ANSI/IPC-CC-830 ISO 9002" I'm not affiliated with that company in any way. Carl Ramer, Engineer Controls & Protective Systems Design Space Gateway Support, Inc Kennedy Space Center, Florida Unsponsored professional posting

Posted by Ed Piper on 3 August, 2001 - 10:49 am
It is my understanding that Tropicalization is intended to inhibit fungus contamination of fungus-nutrient components. This may be accomplished by varnish treating circuit boards with a product such as Humi-Seal Type 1A33 with fluorescent additive, Class A, or Sterling T-394A Fungus Resistant Varnish, Class A. Varnish may be applied by spraying, brushing, dipping or any combination thereof. To determine completeness of varnish coverage, the treated materials can be examined for fluorescence under an ultra-violet lamp. Coated surfaces will show with a light blue hue.

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