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16 BioPharm International eBook March 2021 www.biopharminternational.com • Particulate shedding over time during routine operations, • as shown by comparing the performance of two different types of garments • Life cycle of a garment (deter- mined by studying the per- formance of a garment after repeated laundry cycles) • Assessing the overall heat load of the operator during routine cleanroom operations. BACKGROUND The perfor mance of any clean- ro om ga r me nt dep e nd s on it s desig n a nd per for ma nce c ha r- acteristics. Generally, garments are offered in single-use for ms (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 pre- vent 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 influence the selection of spe- cific 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 evaluate the fabric's abil- ity to contain particles that have been generated while in use; the propensit y of the fabric or gar- ment to generate particles or lint; the ability of the gowning pro- cess to control cross-contamina- tion or bacterial transfer; and how comfortable the garment is for the individual operator. Other tests examine the risks posed by aging cleanroom suits, variations in the thermal heat generated within the suits, and other factors. Usef ul as these methods may be, they still cannot determine the garment's ability to prevent any operator-generated particu- late or microbial contamination f rom e nte r i n g t he c le a n ro om atmosphere during actual use. A poorly designed suit or an inade- quate fabric will not provide the required cleanliness and may even pose a risk to the process. The information provided by the fab- ric manufacturers typically does not address the dynamic use of the garment. TESTING UNDER DYNAMIC CONDITIONS Measuring the effectiveness of gar- ment materials under dy namic conditions requires experiments that quantify the amount of partic- ulate contamination released while garments are in use. Aerosol parti- cle counts measured "in-use" can be highly variable if these tests are performed in an open cleanroom with a single particle counter. The conditions in the room (i.e., airflow, temperature, and humid- ity) can interfere with the result- ing data. This can make it difficult to interpret whether the opera- tor or the gown was the primary source of contamination. To m i n i m i z e a nd ove rcome t hese va r iables, t he st ud ies i n this paper were conducted using a "body box" located within an I nter nat iona l Orga n i zat ion for St a nd a rd i z at ion ( I S O) C la ss 5 cleanroom. A body box is a test cha mber const r uc ted of clea n- ro om mate r ia l s w it h a H E PA - f iltered ceiling. Unid irec t iona l airflow is passed over the person inside the chamber during this test ing. T his met hod has been accepted for studying the protec- tive efficacy of clothing systems in use (1). Design T he d e si g n a nd c on s t r uc t ion of a gowning system is covered in g reat detail in the Instit ute of E nv i ron menta l Sc ience a nd Technology's RP-3 guidelines (1). Gowning design elements such as length of zipper, size of the sleeve and leg openings, and the type of sewing used in the seams can have a very large impact on the per- formance of the garments in the cleanroom. Add it ion a l ly, c onc e r n s w i l l include ease of donning and doff- ing of the garment, and the ability of the material to withstand the gowning process without becom- ing comprom ised or da maged. Other elements such as the type of seam, zippers, and threads can be a source of contamination. If these elements are not com- patible with the gowning process, inferior in design, or ill-suited to the level of activity in the clean- room, the garments may be ripped or damaged in the course of nor- mal activities. A torn or damaged gown would require that the oper- ator wearing it leave the cleanroom immediately and that the product being produced be evaluated for any possible contamination. Processing/cleaning In addition, the process used to clean the garments must be considered. Every cleanroom garment, whether it is worn once or many times, must be cleaned before being introduced to the cleanroom. The cleaning process for a garment can include the soil sorting of garments, which g roups like gar ments together; specialized wash processes using appropriate detergent and purified Regulatory Sourcebook Operations