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12 Pharmaceutical Technology REGULATORY SOURCEBOOK MARCH 2021 P h a r mTe c h . c o m Operations Background The performance of any cleanroom garment de- pends on its design and performance characteris- tics. Generally, garments are offered in single-use forms (typically made from nonwoven materials) and as reusable, woven types, which are often made from high-density polyethylene. Regardless of type, cleanroom garment fabrics are engineered to optimize the following properties: • Barrier (i.e., the ability to prevent particles from migrating through the material) • Strength (ability to remain in service) • Cleanliness and inertness, so that they don't generate lint or particles on their own. The most critical process steps can inf luence the selection of specific material. Usually, the final process step dictates that garments made of the cleanest and most durable fabric be used. Several laboratory methods are used to test the effectiveness of cleanroom garments, including tests that evalute the following: • The fabric's ability to contain particles that have been generated while in use • The propensity of the fabric or garment to gen- erate particles or lint • The ability of the gowning process to control cross-contamination or bacterial transfer • How comfortable the garment is for the indi- vidual operator. Other tests examine the risks posed by aging clean- room suits, variations in thermal heat generated within the suits, and other factors. Useful as these methods may be, they still can- not determine the garment's ability to prevent any operator-generated particulate or microbial con- tamination from entering the cleanroom atmo- sphere during actual use. A poorly designed suit or an inadequate fabric will not provide the required cleanliness and may even pose a risk to the process. The information provided by the fabric manufac- turers typically does not address the dynamic use of the garment. Testing under dynamic conditions Measuring the effectiveness of garment materials under dynamic conditions requires experiments that quantify the amount of particulate contamination released while garments are in use. Aerosol particle counts measured "in-use" can be highly variable if these tests are performed in an open cleanroom with a single particle counter. The conditions within the cleanroom (i.e., airflow, temperature, and humidity) can interfere with the resulting data. This can make it difficult to interpret whether the operator or the gown was the primary source of contamination. To minimize and overcome these variables, the studies in this paper were conducted using a "body box" located within an International Organization for Standardization (ISO) Class 5 cleanroom. A body box is a test chamber constructed of clean- room materials with a high-efficiency particulate air (HEPA)-filtered ceiling. During this type of testing, unidirectional air- f low is passed over the person inside the chamber. This testing method has been accepted for study- ing the protective efficacy of cleanroom clothing systems in use (1). Cleanroom garments should be tested dynamically, to assess the impacts of particle shedding, laundering, and changes in heat load.