By Bob Baker

In last months article, we discussed the role of conventional or Hospital type disinfectants in helping the IAQ professional eliminate sources of microbial contamination in HVAC systems. In this article we will learn about the composition of some popular products and their advantages and disadvantages.

First and foremost, read the label. Many of us often ignore this excellent bit of advice. We rationalize by saying that we know how to use the product. Or we believe the label just contains a bunch of exaggerated claims put there by the manufacturer to better sell the product. Actually, neither of these beliefs is correct, especially with disinfectants.

Incorrect Usage

First, few people use disinfectants correctly. For example, nearly all disinfectant labels say to allow surfaces to remain wet for ten minutes for the best result. In practice, many users, especially those using a spray application, will spray the liquid on and immediately wipe it off. Most, if not all of the germ killing action is lost as a result.

By law, disinfectant manufacturers are prohibited from placing inaccurate or misleading information on their labels. The Environmental Protection Agency (EPA) controls the content of these labels and requires that companies support the information on the labels with scientific facts and tests. Therefore, the information is very useful.

Understanding the Label

The front label of a disinfectant contains the product name and the manufacturer's (or distributor's) name and address. You can always call or write that company to get more information. The front also contains a list of the "Active" Ingredients. That is not to say that other ingredients not listed do not have value in the formula. The so-called actives, are those ingredients that are responsible for the germ killing action of the product. Federal law requires they be listed. Since they are often the most toxic ingredients, the active ingredient listing can help you select the product that offers the best combination of safety and effectiveness for your uses. The front label also usually contains a couple of numbers that are important. The first is the EPA Registration Number. This is your assurance that the product is legally registered with the EPA as required by law. The second (usually proceeded by EPA Est. or establishment) is the number of the manufacturing plant where that product was produced. Part of that number is a two letter abbreviation of the state where the manufacturing plant is located.

The next section is entitled "Directions for Use." This section is normally on the back or side of the container. It not only describes how to use the product correctly, but also the locations and applications it is designed to be used for and the type of organisms it will control. For controlling germs in and around HVAC systems, you want a product that will control a full range of organisms yet is reasonably low in toxicity. You should look for listings for Bacteria, Viruses, Fungi, and Mildew, at a minimum. It is also desirable to find a product that is a combination cleaner/disinfectant and one that is effective against Tuberculosis (TB). All of this information is in the "Directions for Use" section.

The final section of the label outlines certain hazard statements associated with use of the product. All EPA registered products have hazard statements associated with their use. The labeling requirements for disinfectants require that hazard statements be clearly stated. What is important for the IAQ professional are hazard warnings associated with breathing fumes from the product. If the label in any way states that respiratory protection must be used when using the product, you should think twice before using the product in any HVAC application. It is important to also follow all other precautions. Most disinfectants can cause eye and skin irritation so these are the most frequent warnings you will find. The hazard statements are based on the concentration the product is sold in rather than the final dilution. Highly concentrated products will usually have a much lower level of toxicity when they are diluted. For these products, you should refer to the Material Safety Data Sheet (MSDS) for indications of precautions required with the diluted product. For products marketed at full strength, the label precautions should be accurate.

Problem Ingredients

Although there are many different combinations of product ingredients, there are some that should be avoided in air-conditioning applications. Alcohols (Isopropanol, Methanol, Ethanol) are some of the VOC's that have been found to contaminate the indoor environment. You should avoid any product that contains a high level of alcohol. Chlorine (hypochlorites), Glutaraldehyde, Iodine (Iodophors), and phenolics are all compounds that are highly irritating or toxic when breathed. Most formulations that contain these ingredients have the potential for releasing fumes that can add contamination to indoor air. They should be avoided except for applications where they cannot possibly cause indoor air problems.

Acceptable Ingredients

Some chemicals used as preservatives in such things as cosmetics and shampoos (especially the bromonitroalkanols) are very low in toxicity and do not endanger the environment. Therefore, they can be used with confidence within the HVAC system. These, however, are too slow in action for some applications and therefore are classed as sanitizers rather than disinfectants. Almost as low in toxicity are Quaternary Ammonium compounds (such as n-Alkyl dimethyl benzyl ammonium chloride and n-Alkyl dimethyl ethylbenzyl ammonium chloride). They may be used in HVAC applications where they will not easily be drawn into the air-stream such as drain pans and exterior surfaces with little risk. As an added bonus, formulations made from these tend to be excellent cleaners. You get a surface cleaner that also effectively kills germs. Some of these disinfectant/cleaners are effective against the full range of organisms we are concerned about, including TB.

Although disinfectants have long been used in the food preparation and health care industries, today's need for effective control of microorganisms that contaminate indoor air make them an essential tool for the modern HVAC service technician. This series has been written to help you make intelligent choices among the many products available.

Mr. Baker's field of expertise is the control of contamination in air-conditioning and ventilating systems by mold, mildew and bacteria. He writes and speaks frequently about the efficacy, legal risks, and regulatory issues involved in various control strategies. He serves on ASHRAE Technical Committee TC 2.3, TC 2.4, TC 9.8, and Sampling of Airborne Particulate Concentration in Commercial and Residential Buildings GPC 17P. He also serves as a member of ASTM D22.06 (Indoor Air Quality) and is on the Board of Directors of the Indoor Air Quality Association and the Florida Public Health Foundation. Because HVAC applications encompass new uses from an U.S. EPA regulatory standpoint, Mr. Baker works closely with the EPA and industry groups, including serving as the chair of the IAQ committee of the Consumer Specialty Products Association, to help formulate policy in this area.

Bob Baker is Chairman and CEO of BBJ Environmental Solutions, Inc., a company specializing in providing clean air through environmentally responsible products, such as BBJ MicroBiocide , BBJ Micro Coil Clean , "FreshDuct Odor Eliminator ", and BBJ Mold and Mildew Remover™ as well as the revolutionary new Power Coil Clean™. For additional information, Mr. Baker can be reached at (800) 889-2251 or through the company web site at http://www.bbjenviro.com.