1. ChemDAQ Inc. • 300 Business Center Drive • Suite 330 • Pittsburgh, PA • 15205 • phone 412.787.0202 • fax 412.788.2526 Continuous Monitoring vs. Badges Badges are designed to provide the Time Weighted Average (TWA) data for the total exposure period. They contain an absorption medium that reacts with or absorbs and holds the target chemical from the air to be analyzed l ater, which indicates the exposure after the fact. Badges, sample tubes and wet chemical methods were the predominant technologies for monitoring workplace exposure to chemicals until the 1970’s and 1980’s when continuous gas monitors became available. Continuous monitors are electronic instruments that use sensors to provide continuous, real time readings of the target gas concentration and also provide instantaneous alarms if the concentration exceeds the pre - set exposure limits. Continuous monitors a re now available for over twenty compounds and growing, because of their vast improvement in safety and reliability and have almost entirely displaced badges, except for a few chemicals for which continuous monitors are yet not available. As a result, badg es are almost never used in industries where a focus on safety is essential. While some gas leaks develop over time, others occur much more suddenly. The main question one must ask is; “Can a badge warn me in the event of a gas leak?” The answer is No! A badge will definitely not warn you if there is a leak and it is not designed to do so. A badge is designed to document TWA exposures after the fact, not to detect short term exposures or unexpected leaks. Continuous monitors are designed to respond to sudden leaks in a few seconds warning employees of a gas leak before they are overly exposed. Continuous monitors have a higher up - front cost than a pack of badges; but once purchased, the on - going costs of calibration etc. are much less. Badges are sing le use devices and must be purchased for each use, but the major cost of a badge is the analysis; whereas a continuous monitor usually lasts for years. If an employer monitors the work environment every day, he or she will soon find the continuous monitor much more economical, and provide s a safer work environment. The industrial hygienists and managers will be happier too. Many continuous monitors log the data which can be downloaded to a computer, providing records. The equipment typically allows the hy gienist or manager to quickly produce gas concentration vs. time reports; so it is easy for them to show OSHA inspectors, employee representatives or interested parties that their people have not been exposed. For the common sterilant chemicals used in he alth care today, why would anyone utilize exposure badges, a technology made obsolete forty years ago, instead of modern continuous monitors which are cost effective and much more efficient thereby improv ing workplace safety far beyond what is possible with badges.