Cleanroom arc thermal & flame-resistant apparel program
January 6, 2008
The task of creating compliance to multiple, divergent standards (cleanroom standards, sterilization standards and safety standards) can be daunting. The implementation and execution of a cleanroom compliant apparel program requires the cleanroom operators to wear a cleanroom compatible apparel system (coveralls, hood, boots and sometimes undergarments) constructed of 100-percent polyester to prevent contamination of the cleanroom and the products and processes in the cleanroom.
However, when ignited, 100-percent polyester will melt and likely cause injury to the cleanroom operator/electrician if exposed to electric arc or flash fire. Traditional flame-resistant (FR) clothing is constructed of flame-retardant treated cottons or an inherently flame-resistant material. These garments will shed particles that will compromise the integrity of the cleanroom and contaminate the products and processes in the cleanroom. The FDA regulated industries mandate that if these garments are worn in a sterile cleanroom environment, they must be validated.
Compliance to NFPA 70E (National Fire Protection Association) in cleanroom environments requires that all personnel working on electrical equipment operating at >50 V wear arc-flash protective apparel to prevent injury. Polyester is specifically prohibited under any circumstances when exposed to live electrical parts operating >50 V. The automotive industry has been using cleanroom FR apparel meeting ASTM F1506 for workers exposed to electric arc for several years in their cleanrooms, and recently the pharmaceutical, semiconductor and other contamination control industries have begun wearing cleanroom arc thermal flame-resistant apparel in their manufacturing cleanrooms.
Cleanroom FR fabric
A certain filament1 is used to create the flame-resistant characteristic in fabrics for cleanroom applications. Normal woven FR yarn generates particles in the cleanroom, however the filament1 used in cleanroom FR fabrics uses the same FR chemical structure but in a filament form to replace the fibrous forms. In most of the FR cleanroom fabrics, filament1 and carbon yarn is combined and woven into fabric. This resulting fabric is flame-resistant, cleanroom compatible, gamma compatible and static dissipative.
Allocation requirements to military apparel and the Department of Defense have created a lower supply for domestic, commercial manufacture of cleanroom FR fabric. Many orders placed today for cleanroom FR apparel may not be completed for six months, but research and development is ongoing to find other compliant materials for cleanroom applications.
Typical cleanroom apparel constructed of cleanroom FR fabric meet NFPA 70E Category1. Seam construction of cleanroom FR apparel must comply with IEST-RP-CC003.3 (e.g., 100% Nomex® filament thread for sewing, serging of all rough edges and flat feld seams, etc.) to assure cleanroom compatibility, durability of the seams and encapsulation of particles. All other components, such as zippers with protective tape, protective snaps, tunnelized neoprene wrist closures, etc., in the garment must also be cleanroom compatible, gamma compatible and flame-resistant. FR cleanroom apparel must meet ASTM F1506 and be labeled as such to meet NFPA 70E.
The validation process
The validation of the cleanroom FR garment system includes all the results of the tests performed to confirm cleanroom compatibility, gamma compatibility and flame resistance. Testing of cleanroom FR apparel must be performed to validate arc-flash resistance per ASTM F 1959 to determine the arc rating. The sterility of the garment per ANSI/AAMI/ISO 11137-2006 over time must be validated in the FDA regulated industries as well as the durability of flame resistance after many exposures of gamma radiation.
Over the past ten years a new generation of fabrics constructed of Nomex® and durable carbon threads, and cleanroom compatible snaps and zippers encased in Nomex® fabric has been developed. These garment systems are cleanroom compatible, gamma compatible and flame-resistant. Fabrics are now specifically designed to meet the arc thermal and flame-resistant requirements of cleanroom operations.
The validation of cleanroom arc thermal and flame-resistant apparel begins with the Master Plan. The Master Plan is the overview of the lifecycle of the validation process. A Master Plan outline is created that defines the steps and benchmarks of developing the validation protocol, the installation qualification, operation qualification, performance qualification and change control.
In all of these phases, Standard Operating Procedures (SOPs) are prepared and serve as the blueprint to perform each of the qualifications. A change control process is used, if any part of these results fails to meet the required specifications, to make a change to either the specification or the system.
Once the validation protocol is developed, the SOPs written, and training and responsibility assigned, the validation process is initiated.
The installation qualification (IQ) documents that the arc thermal flame-resistant cleanroom garment compares, at minimum, equally in fabric, construction and barrier specifications, if not better than the currently used reusable cleanroom apparel. All of this supporting data (i.e. tear tensile strength, static decay, surface resistivity, pore size, moisture vapor transition rate) and documented evidence is usually provided by the supplier of the fabric and components and the manufacturer of the apparel and is reviewed during a vendor audit.
The operation qualification (OQ) documents that the arc thermal flame-resistant garment system compares equally during normal processing operations, if not better than the currently used reusable cleanroom apparel. Typical monitoring test results of both viable and non-viable particles of the apparel system (i.e. Helmke Tumble test, Body Box and Bacterial Filtration Efficiency) should provide the required documented evidence to compare the arc thermal flame-resistant apparel system versus the reusable apparel system.
The performance qualification (PQ) documents that the arc thermal flame-resistant apparel system compares equally over an extended period of time, if not better than the currently used reusable apparel. The same monitoring test results of both viable and non-viable particles of the apparel system and the same fabric testing performed initially before the laundering process began (i.e. tear tensile strength, static decay, surface resistivity, pore size, moisture vapor transition rate) as well as gamma compatibility should provide the required documented evidence to prove the arc thermal flame-resistant cleanroom apparel are as robust and reproducible as the reusable cleanroom apparel.
Once all the documentation is accumulated from the installation qualification, operation qualification and performance qualification, a summary report is prepared. This completes the validation process and completes the execution of the Master Plan. The summary consists of a summation of the lifecycle that has been outlined in the validation protocol, documentation of the testing and verification of test data. Once data is compiled and verified, statistical analysis is performed on the data and included in the summary report.
Cleanroom protocol meets FR protection
If cleanroom operations require compliance to NFPA 70E Hazard/Risk Category (HRC) 2, a compromise of the two specifications must be weighed (increased contamination of the cleanroom versus protection of cleanroom operators/electricians). Some companies have chosen to provide flame-resistant undergarments (FR cotton protective apparel or undergarments constructed of Nomex®) to wear under cleanroom FR apparel. However, the same undergarments constructed of Nomex® may be worn alone in ISO Class 6, 7 or 8 cleanroom operations and meet HSC 1 level.
Constant research and development of the construction of arc thermal flame-resistant cleanroom garments and of meeting the compromises of wearer comfort, cleanroom compatibility, gamma compatibility and flame resistance (both Category 1 and 2) characteristics is being conducted by fabric and garment manufacturers worldwide, and new dual-layer systems are available now that offer cleanroom compatibility and HRC 2 compliance.
SIDEBAR: Change controlDuring the validation process of the cleanroom FR garment system, changes may be required. Change control is the process of providing documented evidence of any change that has been performed, for any reason. Once it is determined that change is required, the change is documented and implemented. After implementation of the change, the changed process must be revalidated.
SIDEBAR: The right apparel helps keep the cleanroom cleanThe cleanroom industry is acutely aware of the many possible sources of contamination that threaten cleanroom operations. The most significant threat is also the threat that is easiest to control â€” the humans working in the cleanroom.
One of the most significant methods for reducing human contamination in the cleanroom is through a complete cleanroom uniform program. Cleanroom apparel is designed to capture and entrain particles and not allow contaminants to be dispersed into the cleanroom environment. Apparel protects the environment from numerous contaminants that are generated from the human body, including:
• Viable particles such as bacteria and yeasts;
• Non-viable particles such as hair, dead skin cells and dandruff;
• Elements such as sodium, potassium, chloride and magnesium.
The Institute of Environmental Sciences and Technology (IEST) published the latest revision of the recommended practice for garments, IEST-RP-CC003.3, “Garment Considerations for Cleanrooms and Other Controlled Environments.” This document is a tremendous resource for determining the fabric, garment system and garment configuration for your cleanroom application. This recommended practice provides guidance for the selection of fabric, garment construction, cleaning and maintenance of cleanroom garments, as well as for the testing of cleanroom apparel and components for use in aseptic and non-aseptic cleanroom environments.
â€” Jan Eudy, Cintas Corp.