Q: Could you provide an overview of standards related to certification testing of controlled environments?
A: “Let’s not be afraid to speak the common sense truth: you can’t have high standards without good discipline.” –William Hague
While controlled environments come in many flavors and cross multiple industries and disciplines, the establishment of set, uniform criteria to test and certify cleanrooms across this platform is critical to ensuring optimal performance in this wide array of facilities. And the master references for these standards are issued by the National Environmental Balancing Bureau (NEBB: www.nebb.org/procedural-standards/)—a nonprofit organization founded in the early 1970s to provide training and further the advancement of the industry and develop standards, some of which are outlined below.
While the NEBB offers guidance and standards across a variety of building components ranging from building enclosure testing to measurement of sound and vibration, as well as whole building systems technical commissioning and fume hoods performance testing, in this column we’ll touch base on the standards associated with certified testing of cleanrooms. The URL listed above will provide access to these and others standards—a handy location to electronically bookmark.
When undertaking cleanroom performance testing (CPT), it’s important to engage a CPT firm certified by the NEBB. The standards laid out in the NEBB guide are promulgated as the minimum requirements one should undertake in cleanroom testing and certification.
NEBB certifies firms, professionals, and technicians through a series of required background, experience, and rigorous examinations—with annual requirements for both firms and individuals to maintain their certification.
The process
Delivering a successful cleanroom testing project requires a team approach: comprised not only of the CPT firm but also the owner, architects and engineers, and key construction team members. While a collaborative approach is necessary for success, it should be clearly established that the owner must be the final decision maker regarding the testing process and components.
The NEBB outlines in detail the responsibilities of each team member in their Procedural Standards for Certified Testing of Cleanrooms, providing a roadmap to project success. Make sure all your team members understand their roles and responsibilities at the outset, and that these requirements are written into the contract documents.
The responsibilities of a certified CPT professional
The NEBB clearly outlines the responsibilities of a CPT professional—underpinned by the ultimate responsibility to control the quality of the work, and satisfying the quality of the project testing, “exclusive of acceptance criteria or guaranteeing performance.”
Thoroughly understanding the role of the CPT professional forms the foundation for testing success. Below are the responsibilities as outlined by the NEBB:
1. Execution of CPT procedures
2. Technician training
3. Cleanroom procedures training
4. Instrument use and maintenance
5. Coordination/supervision
6. Project communication
7. Field work completion
8. Compilation and submission of final cleanroom reports
9. Project completion
Responsibilities of the owner, design, and construction team
The alignment and coordination between the project owner, the design team, and the contractors will largely influence the project’s success. Striving to create a proactive, cooperative team atmosphere—where every problem is owned by all, as are developing every solution—is most productive.
According to the NEBB, clearly delineating the required tests, measurement parameters, and allowable tolerances may be the most critical responsibilities of this team. The more clearly a team can define and outline those systems requiring testing, and clearly delineate the tests on the architecture and engineering plans, the more smoothly the project will run. Don’t leave any systems testing to guesswork.
Accurate instruments
Without accurate instruments, all is lost.
In all testing, it’s critically important that the CPT consultant own, calibrate, and maintain the necessary instruments to successfully complete the cleanroom certification tests. Be sure your CPT firm has the accuracy of their instruments verified by a testing lab that can be traced through the National Institute of Standards and Technology (NIST) for domestic U.S. projects or the NIST’s counterparts in other countries. The NEBB guide outlines calibration requirements for each instrument, including range, accuracy, and resolution where applicable, by testing function—and the schedule under which each piece of equipment should be calibrated.
The NEBB has structured their testing standards and levels of prescription by using the words, “shall, should, may” to delineate those tests that are required, those where sound practice dictates certain tests should be undertaken, and those that the owner and CPT firm determine the benefits of and data from specific tests may be worthwhile.
Key tests
At the end of the day, it’s primarily about particle counts, control, and airflow when considering the baseline requirements of a certified controlled environment. The NEBB outlines the following primary tests, with detailed information in their procedural standards guide:
• Airflow velocity and uniformity tests
• Airflow volume and uniformity tests
• Filter installation leak tests
• Airborne particle count cleanliness classification tests
• Room pressurization tests
Secondary tests
The NEBB outlines the following tests as optional (determined by the user), relating to ancillary cleanroom systems, particle and air movement:
• Airflow parallelism tests
• Recovery tests
• Lighting level and uniformity tests
• Sound level tests
• Vibration level tests
• Temperature and humidity uniformity tests
• Electrostatic tests
• Conductivity tests
• Electromagnetic interference (EMI) test
• Air change rate (ACH) test
• Bench scan filter leak tests
It is wise for the design professional to stipulate cleanroom performance testing requirements in the project contract documents. The NEBB provides a full set of requirements on their website, available in electronic format for ease of customization.
Warning: The design engineer of record is ultimately responsible to tailor the standards to meet the unique aspects of their project. This is not a responsibility that one can pass off—function and performance hang in the balance of undertaking a well-structured testing program.
Finally, the NEBB Procedural Standards for Certified Testing of Cleanrooms provides a very comprehensive appendix of references and reference publications to guide project teams, owners, and the engineer of record detailed information through the intricacies of specific project types. Such a comprehensive guide to this critical process for controlled environments should be bookmarked by every cleanroom facilities engineer.
Richard Bilodeau, PE, is director of engineering at SMRT, architects and engineers (www.smrtinc.com). His 30 year career includes plant engineering positions in clean manufacturing. Richard has engineered, designed, operated, and supervised the construction of numerous controlled environments and labs for advanced technology, life sciences, industrial, healthcare, academic and corporate clients. Dick can be reached at [email protected] or [email protected]
This article appeared in the June 2014 issue of Controlled Environments.
