4 Advice to Choose a coil coating technology

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Have you ever heard of coil coatings? In the HVAC business, they&#;re used to prevent corrosion on the important elements of an HVAC system. In this article by Contracting Business, Bob Martinelli, the Director of Corporate Development at RectorSeal, tells us all about coil coatings and how they can protect HVAC units:

&#;Applying aftermarket protective coil coatings is critical to sustaining the full lifecycle of newly-installed HVAC equipment destined for corrosive environments, but many engineers and contractors don&#;t specify this important step.

Coastal areas are the most likely target markets for coil coatings. Salt spray from oceans can prematurely corrode outdoor HVAC coils in as little time as a year if not coated before use. Salt spray can travel as far inland as 10 miles, which creates a huge area of vulnerable equipment on North America&#;s seaboard.

Protecting HVAC equipment with coil coatings isn&#;t a new concept. For many years, HVAC manufacturers have shipped newly-made coils directly to coating specialists as per the specification of engineers and contractors. Sensitive parts, such as electrical components, are masked-off, then coils are sprayed or electro-coated before the unit is shipped and installed in their corrosive environment destination.

What is new today are coatings that have been packaged in game-changing, convenient easy-to-use aerosol cans. Contractors can now coat coils in their shop or onsite before installation. This skips the past time and effort required to send a coil or the entire unit out for factory-applied coatings. Furthermore, contractors can create an entire do-it-yourself (DIY) coating niche that requires minimal experience or training.

When selecting a coil coating it is important to make sure that the product has passed ASTM B117 test standards for salt spray. It also should have multiple marine and industrial ASTM test standard listings for resisting ultraviolet (UV) rays, acid rain, high concentrations of urban vehicle emission air pollutants and other outdoor contaminants. It&#;s also important to choose a brand that with a long history and reputation for providing OEM-approved, factory applied coil coatings.

When To Use A DIY Coating

Deciding when to use a coating specialist versus a contractor with field-applied DIY aerosol applications, usually depends on the project scope. For example, it&#;s more economical to request the manufacturer ship 200 new split system condensers to a factory-coating specialist if the units are destined for a beachfront condo complex. However, a contractor using DIY aerosol protective coatings for a beachfront home&#;s condenser(s) can be very economical and reduce the installation time versus shipping the product(s) to and from a coating specialist. As for unit size, typically any HVAC coil in a system 10-tons or smaller is perfect DIY coating application.

While coastal areas play a large part in coil corrosion, other potential areas where premature coil corrosion can occur are:

• Urban areas, and particularly airports, which have heavy concentrations of airborne vehicle emissions
• Buildings near or located inside properties of waste water treatment plants
• Any heavy industrial area that emits airborne chemicals
• Restaurants where cooking grease particulates are exhausted in  close proximity to the HVAC rooftop system
• Heat Transfer and Static Pressure Considerations

Many engineers and contractors have questions about how the coatings will effect a coil&#;s heat transfer performance. While some coating formulas might be borrowed from other industries, only coatings designed specifically for HVAC coils  should be used, because they&#;re formulated for negligible heat transfer loss. These specialty coil coatings are typically only 1.4-ml thick or less, versus other thicker industrial coatings that can negatively affect heat transfer.

Static pressure is also a consideration, but coatings designed specifically for HVAC coils don&#;t increase the pressure drop through the coil. Instead, they may even lower the pressure drop versus an uncoated coil, because less static pressure-increasing contaminants will reside or adhere to the coil surfaces.

Of course, there&#;s more to consider about corrosion than its effect on static pressure. Corrosion, especially from salt, can create formicary and pitting processes that ultimately lead to leaks.

How DIY Coatings Are Applied

Contractors can apply DIY coil coatings in the field, or in their shop. Obviously, shop-applied coatings are preferred, because of the controlled environment for temperature, humidity with no challenges from wind.

&#;Clean&#; and &#;dry&#; are key to a good coating adhesion. The first step mandates cleaning the coil with a foaming, non-acid, non-caustic coil cleaner and then thoroughly rinsing the coil. Many contractors believe that new coils are clean. However, most new coils have machining oil residue from the manufacturing process that must be fully removed for successful coating adhesion.

While contractor-applied coatings are designed for new units, if an older unit that has already been exposed to corrosion is being coated, it should be treated first with a purposely-formulated salt and oil removing coil cleaner.

Once the coil has been cleaned and is completely dry, the electrical contacts, moving parts, valves, compressors and other parts not to be coated, are masked off with blue painter&#;s tape, which doesn&#;t leave a residue and is easily removed. It might also be beneficial to coat the unit&#;s compressors and accumulator to minimize the corrosive environment&#;s effect on these key components.

The coating stream is sprayed approximately 4-inches away from the coil in similar movements to spray painting. Some coatings are clear, which allow the coil to appear aesthetically uncoated. Other coatings are blue, for when the applicator prefers to visibly track even coverage of the sprayed area. Drying times for touching is 10 minutes; handling is 20 minutes; recoating is 30 minutes; and a full cure typically requires 48 hours.

During use, the corrosive elements in the air will attack the coil&#;s coating instead of the copper and aluminum surfaces. For this reason, coatings may need a re-application every five to 10 years depending on the environment&#;s corrosiveness.

Coatings are essential for coastal areas, however engineers and contractors should also consider the prospect of coating coils in high air pollution areas such as urban centers and airports also. In any corrosive situation, coatings will help improve the efficiency of the unit and maximize the unit&#;s useful life.&#;

Have a question about coil coatings? Contact our HVAC business for more information.

If you are looking for more details, kindly visit coil coating technology.

*Photo courtesy of crttipster.com

PPGI Coils are available in a wide variety of colors, how to choose the right color for you among the many PPGI Coils ? Avoid its color difference, let's come together to understand it.

Color Coated Plate Coating Color Selection:

the choice of color is mainly to consider the match with the surrounding environment and the user's hobby, but from the point of view of the use of technology, light-colored coatings of pigments to choose a large margin of choice, you can choose superior durability of the inorganic pigments (such as titanium dioxide, etc.), and coatings with a strong thermal reflectivity (reflectivity coefficient of the darker coatings up to double the summer coatings) the temperature of the coatings themselves are relatively low, which is beneficial to the extension of the life of the coatings This is beneficial to the coating life extension.

In addition,

I remind even if the color coated coil coating discoloration or chalking, light color coating film changes with the original color of the contrast is small, the impact on the appearance is not big. The dark color (especially the more bright colors) using organic colors mostly, easy to fade when exposed to ultraviolet radiation, short of 3 months to change color. For color coated steel, usually coating and steel plate thermal expansion rate is different, especially the metal substrate and organic coating of the coefficient of linear expansion of the difference is large, when the ambient temperature changes, the substrate and the coating interface will be combined with the expansion or contraction of the stress, if not properly release the coating cracking will occur.

Here To Illustrate Two Points Of The Current Domestic Market Selection Of Misunderstanding:

1.A Large Number Of White Primers Currently Exist In China.

The purpose of using white primer is that the thickness of the topcoat can be reduced, because normal corrosion-resistant primer for construction is yellowish-green in color (hence the strontium chromate pigment), and there must be a sufficient thickness of topcoat.

2.the same project of color coated steel plate for construction project using different vendors,

different batches of color coated steel plate, in the construction of seemingly the same color, but after a few years of sunlight, different coatings of different vendors of different color change trend is different, resulting in a serious color difference, there are too many examples of this. Even if the products of the same supplier, it is strongly recommended to order for the same project at one time, because it is possible to use the products of different coating suppliers for different batches, which increases the possibility of color difference.

Author: Bella Niu

The Introduction Of Author I am a very very enthusiastic person and I am very very glad to help you if I have any chance. If you have GI, PPGI, GL, PPGL , Roofingsheet steel industry confusion, or If you have steel internet marketing questions, or a direction, or you have ideas to make investments in , or you are making adjustments, you're not quite clear, welcome to come to Jianhui Steel Bella for advice as soon as possible. If you need steel welcome to contact us! :

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