IAQschool.Online - Docs

NADCA ACR Standard & Guidelines

Issue link: http://iaqnet.uberflip.com/i/637209

Contents of this Issue


Page 38 of 97

n Saves costly replacement of duct board or lining in ductwork or air handler. n Coatings can isolate non-removable particulate from the airstream. n Coatings can smooth the interior profile of surfaces within HVAC systems to make them easier to clean in the future. n Coatings can yield a smooth film surface when dry that reduces the probability of deposition and accumulation of foreign materials that could support future microbial activity. Cons n Does not replace duct cleaning n Adds an additional stage to an HVAC project after initial duct cleaning which will create additional expense. n Occupants may need to leave the building while coatings are applied or curing. n May affect sound attenuation where lining or fiberboard are used for that purpose. n Some odors may linger after application. n Using EPA-registered coatings (with antimicrobial properties) requires some form of licensing in some states which may add additional costs and burdens to the applicator. n System may need to remain shut down for a period of time to allow sealant to cure. EPA requirements Some coatings may contain antimicrobial ingredients to preserve the integrity of the product, but if the product does not make antimicrobial claims, EPA registration is not required. Coatings and sealants used as resurfacing and repair products that do not claim to kill microorganisms, and which claim only to prevent growth on or in the coating film, do not need to be registered by the EPA for use in ductwork. Such products fall within the scope of the Treated Articles Exemption of the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA). The EPA does not intend to register or regulate resurfacing coatings that do not make pesticidal claims. Best practices n Ductwork, components, and surfaces to be coated should be thoroughly cleaned and evaluated before coating for best results. n Materials must be used in accordance with manufacturer's instructions and in accordance with the label. n Correct protective equipment should be used by employees applying resurfacing materials. n Ensure occupants are not exposed to potentially hazardous fume levels during application and drying time. n Users must comply with EPA, state and local regulations. Building codes and/or engineering specifications may require that coatings have been tested to certain ASTM test methods (such as ASTM E 84 and ASTM C 411) as required by the performance protocols of the National Fire Protection Association (NFPA) 90A/90B. (ASTM International is an organization that establishes test methods, among other things.) Before using any resurfacing coating, copies of this testing should be obtained from the product manufacturer. Coil Cleaning Compounds Product Definition Coil Cleaners are a subset of a broad category that includes all hard-surface cleaning agents. These cleaning compounds differ from general-purpose consumer products in that the soil that accumulates on surfaces of refrigeration and air-conditioning coils tends to be more resistant to removal than soil on walls, floors, counter tops and bathroom fixtures. In addition, coil structure (especially aluminum fins) can be more easily damaged than most environmental surfaces. For example, dried layers of organic debris on an evaporator coil can be almost as difficult to remove as baked-on oven soil, however, while a thin aluminum fin is easily damaged, the porcelain or stainless steel surface of an oven is highly resistant to damage. There are three general formulation strategies that manufacturers follow in manufacturing coil cleaners: n Acid: These products combine an acid (phosphoric, hydrofluoric, etc.) with a detergent. They generally have a pH of 3 or below. They work by creating a chemical reaction with the aluminum of the coil fins that mechanically helps release the soil that is then held in suspension by the detergent until it is rinsed off. n Alkaline: These cleaners are formulated by combining sodium hydroxide, potassium hydroxide or some other caustic with a surfactant (soap). They normally have a pH of 10 or above and work in much the same way as acid cleaners by creating a chemical reaction that mechanically breaks soil free. n Detergent: These are more complex formulations. They combine different detergents and other ingredients to create a strong cleaner. There is a wide variety of these formulations and they vary greatly in effectiveness against the types of soil that are found in coils. Detergent cleaners are sometimes called 'neutral' cleaners. This is an error as a

Articles in this issue

Archives of this issue

view archives of IAQschool.Online - Docs - NADCA ACR Standard & Guidelines