Issue



Setting the Standard: Proper personnel practices remain critical to cleanroom operations


07/01/2005







By Gary W. Knoth, Western Digital Corporation


The Institute of Environmental Sciences and Technology (IEST) is responsible for the origination, publishing and revision of approximately 35 Recommended Practices (RPs) on topics of interest and of value to the contamination-control industry. Several years ago, the need for an RP covering basic cleanroom operation and personnel practices was identified as one of these topics. The resulting document (IEST Recommended Practice CC027.1-Personnel Practices and Procedures in Cleanrooms and Controlled Environments) contains a wealth of valuable information not available elsewhere and certainly not within a single document. The RP Working Group is currently revising the document, and anyone interested in the proper way to operate and control the personnel in a cleanroom operation should be sure to obtain a copy.

In creating the original document, the aim was to approach the subject of cleanroom operations from the viewpoint of a novice user-one needing both basic as well as detailed information on how to control personnel operations with respect to cleanroom requirements. As stated in the RP, “this (document) serves as a guide for developing a program to manage contamination caused by, or associated with, the people, processes, and tooling in the cleanroom. Contamination may be generated by the people or the activities they perform, or may be transported into the clean environment with the materials brought into it...”

The RP provides a general description of the elements essential to a contamination-control program as well as specific procedures for minimizing human-sourced contamination. The rationale behind the procedures and elements is also discussed. Finally, the document specifies commonly accepted procedures and recommendations, and also points out considerations that should be made for a thorough and successful program.

The following sections are covered in detail (the words shown in Bold Type indicate subsections under the main topic headings within the RP):

    HIRING: Implementation of a hiring program will typically be done through an HR organization. However, the CC organization should provide input on specific requirements of cleanroom jobs. Physical characteristics to be considered are things such as the policy regarding hiring smokers. The prohibition of facial hair may also be necessary. Large or small personnel may have difficulties with certain aspects of cleanroom work and that should be part of the job description. Heat sensitivity and medical disorders are also discussed. Mental characteristics to be considered are things such as claustrophobia or other conditions that may make working in a cleanroom impossible for some individuals. Basic Job skills such as personal abilities and language skills should also be well-defined to avoid communication and functional issues. Follow-up should be done to ensure that any changing requirements are communicated to HR to avoid hiring incompatible individuals.

      TRAINING/COMPLIANCE: Responsibility for training must be assigned to a responsible group or individual to ensure that all employees are given the proper training and that adequate records are kept. A list of Subjects to be covered by the training course is included as a framework for the training Program design and Program objectives. The use of various types of Research for the development of information specific to company or job requirements is also covered. Available Training methods are listed and Program development is touched upon. Physical arrangements for the training environment as well as Presentation methods, Training aids and learning performance Assessment are discussed.

        • HYGIENE/HEALTH: Personnel considerations such as bathing, hair care, fingernail maintenance and cosmetics are covered. In addition, Illnesses, such as coughs and colds, that can affect the ability to perform a cleanroom operation are defined. Certain Skin conditions and Respiratory concerns, such as smoking, that could have an effect on cleanroom performance are addressed.

          • GOWNING: Gowning is a subject that is typically not covered in detail by most cleanroom operations manuals. In this RP, gowning is covered in detail by addressing three gowning phases: 1) At-home preparation, 2) Pregowning at the workplace, and 3) Gowning in the change room. The details provided in this section are quite valuable to anyone who is starting a new cleanroom operation or wants to improve a current operation.

            • CLEANROOM ENTRY: Cleanroom entry can be done with or without Air showers. The advantages and disadvantages of air showers are discussed, which is valuable because the use of air showers is somewhat controversial. The use of Air locks as an alternative to air showers is also discussed in detail. The possible Configurations for either air showers or air locks are discussed, as is the Cleaning that is required to keep the entrance configuration from being a contamination source instead of a contamination barrier.

              • BEHAVIOR: The Movements and actions of personnel in the cleanroom can have a significant effect on the airborne cleanliness of the area. Proper movement and ways to shield the product from the effects of personnel movement are detailed. Personnel Discipline is discussed with respect to variations from standard procedures. Also a fairly comprehensive list of Restricted materials is provided as a guide to planning the way the cleanroom will be operated and the consumable materials that cannot be used within the cleanroom. Most of these kinds of materials have a clean equivalent that can be used in the cleanroom.

                • STORAGE/CHANGE ROOM: A generic Change room design is provided as an ideal that the facility designer/layout planner should strive to emulate. There is also a discussion of change room Cleanliness classes as they relate to the class of cleanroom being supported. Garment storage is discussed in detail and the reason and justification for using hanging garment storage under vertical unidirectional airflow is provided. The Stocking/Restocking/Disposal of consumables and garments is discussed and a strategy for conducting these operations with the least disruption to change room access is provided. The requirement of and desirable location for a Janitorial support area within the cleanroom/change room area is also covered. In addition, the provision of a Wipe-down station and procedures for the wipe-down of nonproduction materials entering the cleanroom through the change room are detailed.

                  • MONITORING/AUDITING: The Purpose of monitoring and auditing is to ensure that documented practices and procedures are followed so that products produced or procedures performed in the cleanroom can be carried out without being adversely affected by the presence of personnel. The Requirements and Methods of auditing are defined and the Implementation of formal auditing programs is detailed. In addition, ways to confirm Evidence of effective auditing are provided, and the necessary elements of a Quantitative monitoring program are defined.

                    • GOWNING SYSTEM MANAGEMENT: The gowning system definition should begin with Function management, which simply stated means having the correct garment for the requirement. The gowning system and Garment selection considerations are discussed in great detail. Facility requirements for changing areas, lockers, in-use garment storage, soiled garment storage, garment inventory storage and internal inventory transit are defined. Garment sourcing and laundry service considerations are addressed, and the overall Management and administration of a cleanroom garment management system is outlined.

                      • EXITING/EVACUATION: The correct procedure and order of Garment doffing (removal) is covered in detail. Garment storage procedures are addressed, as is the Disposition of used garments that are to be sent for laundering. Damage inspection of the garments by operators is discussed, as is Behavior that can result in garment damage. Exit routes for emergencies and Evacuation garment handling are also covered.

                    The Working Group is currently revising this important RP. The major format changes-particularly the use of metric units as primary measurements with English equivalents in parentheses-will bring the document in line with current IEST guidelines. In addition, all references to Fed. Std. 209 cleanliness classes will be replaced by the equivalent ISO 14644-1 cleanliness classes. Minor changes to content will also be made, along with one fairly major change-the separation of normal exiting procedures from emergency exiting procedures and expansion of both topics. III

                    Gary W. Knoth is a senior principal contamination-control engineer with Western Digital Corporation (WD) in San Jose, California. He is responsible for specification, development and certification of new cleanrooms as well as CC development for new products at WD. Prior to joining WD, he was the Chairman of the IBM Worldwide Corporate Contamination Council where he was responsible for worldwide coordination and communication of IBM CC activities and organized and chaired an IBM worldwide contamination-control conference for ten consecutive years. He has been a member of IEST since 1978 and has chaired Working Group CC027 since its inception and throughout the development of IEST-RP-CC027.1. He currently chairs the reconvened Working Group CC027, which is working on a revision of the existing RP that is expected to be issued before the end of 2005. He also serves as a voting member on five other IEST working groups.

                    ABOUT IEST

                    IEST is an international technical society of engineers, scientists, and educators that serves its members and the industries they represent (simulating, testing, controlling and teaching the environments of earth and space) through education and the development of recommended practices and standards. IEST is the Secretariat for ISO Technical Committee 209, Cleanrooms and associated controlled environments, charged with writing a family of international cleanroom standards. IEST is also an ANSI-accredited standards-development organization. For more information, contact IEST at iest@iest.org or visit the IEST website at www.iest.org.