The design and installation process for a cleanroom is complex, particularly due to the added responsibility to prevent every type of contamination. Clean and careful cable management for electrical and other penetrations is sometimes overlooked during the initial design phase of a cleanroom, which can lead to unintended air leaks in the future. However, this important design factor must be a priority, as it can aid designers in sealing out airborne contaminants that could otherwise leak through improperly sealed wall penetrations.
The sealing solution for a cleanroom needs to be designed, tested, and certified for long-term functionality. The seals must be approved for use in hazardous and potentially explosive environments. Sealing systems must be able to seal all services to high levels of pressure within both negative and positive testing regimes. The system design needs to be resistant to spikes, highpressure fluctuations, and temperature changes, and must be designed to maintain the positive pressure in a cleanroom or the negative pressure level in a contained room. Also, it is crucial that cleanroom seals are able to maintain air-tightness, which reduces validation periods and helps promote a safer operation when utilizing harmful fumigants.
Compact sealing solutions are capable creating an airtight seal with minimal structural alteration, and can work in operation under constant pressure. Certified compact sealing systems can effectively seal services in the most hazardous environments, such as when fumigation takes place. The simplicity and reliability of compact seals allows changes to be made and new services added with great first time validation results.
Efficiently designed and simplified, compact sealing systems are a smart choice for cleanrooms due to their resistance to chemicals. Compact sealing solutions are lightweight, fully mechanical, and have a clean surface finish with excellent resistance to formaldehyde, vapor phase hydrogen peroxide and other fumigants used when cleaning contained rooms.
Compact seals could put an end to the “Swiss cheese methodology” of service routing. Instead of making holes for costly glands, compact sealing units give the option to seal multiple cables in the same opening, eliminating the need for drilling and cutting in live rooms when services are added. Fewer holes in the structure result in fewer possible leak paths. As well, the system combats installer skill variation much better than traditional products such as mastic or compound.
As an added bonus, there are many positive economic benefits to using modular, compact sealing units. These designs have become popular since many cleanrooms have a modular design that is intended to allow future expansion of the original layout without rebuilding from scratch.
Jason Hood is with Roxtec of Tulsa, Okla. www.roxtec.com
This article appeared in the January/February 2015 issue of Controlled Environments.
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