What is special about stitching of cleanroom garments with respect to seam type and construction, thread selection, and other sewing parameters?

I always recommend turning to Institute of Environmental Sciences and Technology (IEST) documentation on a cleanroom subject. The IEST recently published the latest revision of IEST-RP-CC003.3, "Garment Considerations for Cleanrooms and Other Controlled Environments." It outlines all aspects of cleanroom garment systems including the recommended components and construction of cleanroom garments. This recommended practice may be ordered from the Institute of Environmental Sciences and Technology website www.iest.org.

In Section 5.2., "Material Properties and Testing," specifications and evaluation of fabric characteristics are reviewed and evaluated. Section 5.3., "Design of Apparel," reviews specifications and evaluation of the apparel design. In Section 5.4., "Construction of Apparel," the IEST provides specifications of sewing thread (5.4.1.) as follows:

"Sewing thread should be synthetic, continuous, multifilament, and compatible with the fabric cleaning and sterilization process. Silicone and other lubricants or bonding agents, often used in the sewing process, should be assessed for compatibility with end user's contamination requirements."

Contamination control consultants typically specify the use of durable, 100% polyester, silicone-free thread. This thread is compatible with the fabric and seams of cleanroom apparel.

Section 5.4.2. addresses specifications of seam construction. Typically all cut seams are overstitched or serged prior to assembly of the garments. A minimum number of seams are recommended. The seams should be double-needled and flat-felled to enclose all fabric edges and provide durability. This section contains helpful diagrams showing exactly how the fabric should be joined and sewn.

Additionally, the number of needle holes required by stitching of the seams should be minimized and these needle holes generated by the stitching of seams should be comparable to the thread diameter to limit the permeation of particles.

How do I qualify a cleanroom garment supplier for my aseptic cleanroom?

I again recommend checking with the Institute of Environmental Sciences and Technology (IEST) documentation on this subject, and IEST-RP-CC003.3, "Gar-ment Considerations for Cleanrooms and Other Controlled Environments" is the point of reference for this topic. It outlines all aspects of cleanroom garment systems including the servicing of cleanroom garments.

Listed below are the topics that should be addressed during the qualification process. There are hundreds of questions that can and should be asked of the supplier. In addition to asking the questions, the garment supplier should review with you the appropriate documentation to prove processes are being followed. A complete list of questions may be obtained by contacting me directly at eudyj@cintas.com.

Topics to Address When Qualifying a Garment Supplier for an Aseptic Cleanroom

• Recommended Reusable Apparel
• Sterilization
• Process Controls
• Validation
• Process Water System
• Wash Process
• Cleanroom Monitoring and Control
• Customer Service
• Quality Management
• Contract Review
• Organization and Personnel
• Equipment/Facility
• Additional Charges
• Additional Services

If you have questions for Jan, please send them to Chief Editor, Paul Nesdore, at pnesdore@a2c2.com.