Questions and Answers
Following are answers to technical and availability questions about McGill AirFlow's SilverGuard™ ductwork:
What is SilverGuard ductwork?
SilverGuard ductwork was developed as a second line of defense in the fight against bacteria, mold, mildew and other fungi residing in HVAC duct systems. To fabricate SilverGuard ductwork McGill AirFlow uses coil steel pre-coated with an epoxy that includes the antimicrobial compound.
What is the antimicrobial compound?
The antimicrobial compound is a patented zeolite that encapsulates millions of silver ions. Silver, a natural protective element, has been used for over 6,000 years for food and beverage storage. This proven technology is successful in controlling growth of bacteria, mold, mildew and other fungi.
How does the antimicrobial compound work?
Moisture is the trigger. As little moisture as is present on a table top at ambient conditions is all that is needed for microbes to grow and to cause the antimicrobial compound to work. The zeolite acts as an ion pump exchanging silver ions with other ions (Na+, Ca+, etc.) present in moisture. The ion exchange continues until it reaches a state of equilibrium. The silver ions penetrate the microbe membrane and prevent RNA/DNA splitting, thereby inhibit growth.
Where might SilverGuard ductwork be used?
SilverGuard ductwork is recommended for applications where growth of bacteria, mold, mildew and other fungi are a concern and operating temperatures do not exceed 300°F.
What type of coating is on the SilverGuard ductwork?
The antimicrobial compound is incorporated into an epoxy coating which is bonded to the metal surface by heat. Translucent blue pigment is added to the epoxy coating to indicate to what surfaces the compound is applied.
What surfaces of the SilverGuard ductwork are coated?
Both the interior and exterior of the steel ductwork are coated. A clear epoxy coating is applied to the outer surface that offers additional corrosion protection and a more cleanable and paintable surface. Only the coating on the interior surface of the ductwork contains the antimicrobial compound, unless otherwise specified.
Is it necessary to clean SilverGuard ductwork?
Yes, treated articles must still be cleaned to ensure that the surfaces will be free of a build-up of destructive microbes. It is best to view the SilverGuard ductwork as a second line of defense in the fight against bacteria, mold, mildew and fungus in duct systems.
How is the coated steel surface cleaned?
The surface of the SilverGuard ductwork may be cleaned with a mild detergent and a soft sponge or cloth, and then air-dried or dried with a soft cloth. Harsh abrasive cleaners must be avoided in order to prevent damage to the epoxy coating.
How abrasion resistant is the epoxy coating?
The abrasion resistance of the epoxy coating is similar to that of countertop plastic laminates.
If the coating is scratched, will the surface of SilverGuard ductwork still be protected?
Small scratches or weld burns through the epoxy coating will not adversely impact product efficacy. The silver ions contained within the ceramic matrix can still diffuse and migrate to the microbes within the scratch. The active silver ions can "bridge" up to a 1/4-inch gap. Numerous or wide scratch patterns will reduce the efficacy of the product. Contact the McGill AirFlow sales engineering office nearest you to order SilverGuard ductwork epoxy paint for touch-ups.
Won't the epoxy coating separate from the steel when it is formed?
No. Coatings applied to both galvanized and stainless steels have been formulated to allow the metal to be pressed, drawn, bent, roll formed and otherwise fabricated into parts, without loss of the coating or significant effect on the efficacy of the product.
Can SilverGuard ductwork be welded and repaired?
Yes, both spot welded and fully welded joints are possible without the need to remove the epoxy coating. Repairs are easily made using the SilverGuard ductwork epoxy paint.
How long will the antimicrobial compound last?
The durability of the antimicrobial compound will be determined by the environment. Salt spray, water soak and humidity testing has indicated that the antimicrobial benefit will be present as long as the epoxy coating remains on the steel. However, abrasive conditions that cause wear of the epoxy coating will reduce the period of effectiveness.
How do I know that the antimicrobial compound is still inhibiting the growth of microbes?
Controlled laboratory and in-field swab procedures have been developed to show that the antimicrobial compound is still inhibiting the growth of microbes on the interior surfaces of the ductwork. Contact the McGill AirFlow sales engineering office nearest you for more information.
Is anyone using the antimicrobial compound today?
Yes, the antimicrobial compound has been used in Japan for about eight years in paints, flooring, kitchenware and various other consumer products. In the United States, this antimicrobial product is being used in footwear, water bottles, clothing and medical applications. Steel coils with an epoxy coating incorporating the antimicrobial compound are now available. SilverGuard antimicrobial pre-coated steel ductwork from McGill AirFlow is the first such product available in the U.S.
Does the coating on SilverGuard ductwork meet any government or independent standards?
Yes, the antimicrobial compound is EPA registered (No. 71277-1-72854), and the epoxy coating was tested in accordance with UL 723 and found to have NFPA 90A/90B FS/SD ratings of less than 25/50.
Do competitive products exist for SilverGuard ductwork?
Yes. There are several organic post-coating systems available on the market that offer antimicrobial protection. However, the antimicrobial technology is the only one offering the natural protection of silver.
How do I get the SilverGuard ductwork?
McGill AirFlow offers SilverGuard ductwork through all its sales engineering offices nationwide. Please contact the McGill AirFlow sales engineering office nearest you for more information.
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