Saturday, February 8, 2014

Trimming Down Cleanroom Insulation

Ed Sullivan
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In some respects, the insulation traditionally used in cleanroom manufacturing is like those 1980s-era cellular phones—much too clunky and somewhat prone to performance problems. But then, the conventional open-celled polyethylene foam insulation used in cleanrooms dates back to the 1980s or earlier.

The problems with cumbersome insulation designs become very pronounced in the manufacturing cleanroom environment, where thousands of feet of fairly narrow reactor piping form a congested maze of plumbing once the insulation has been installed.

A half-inch line with three-inch insulation becomes 6.5 inches in diameter. When you consider the multitude of lines in the typical manufacturing cleanroom, it’s no wonder the space gets crowded.

“One of the problems with the traditional melamine fiber or foam insulation design used in most cleanrooms is that it severely constricts the space needed by technicians to access the many points in the lines where instruments and controls are located,” explains Mark Ginchereau, vice president of Termar Inc., a Ventura, Calif.-based maintenance contractor and insulation installer.

Ginchereau adds that, until recently, the only alternative to having a cleanroom densely packed with open-celled or polyethylene insulated lines was to build a larger cleanroom and install longer lines so that there would be more elbow room for technicians—an expensive solution.
He mentions other drawbacks to conventional insulation as well. Standard open-celled insulation sheds particulate when cut. This makes it necessary to provide additional protection from cross contamination and exposure. 

Yet, standard open-celled insulation can also shed particulate due to everyday contact from workers who need to gain access through tight spaces. Any uncontrolled particulate shedding can require extensive replacement and unscheduled cleanroom downtime.

Pipe lines can be a maze. Thinner pipe insulation offers more space and easier access for maintenance and repair. 

Ginchereau also mentions that cleanrooms with melamine fiber-filled insulation in some chilled-water applications may be susceptible to condensates forming in fiber, due to chinks or even cracks resulting from impact damage or normal wear and tear from worker contact. Condensate formations can provide a breeding ground for biological growth, a highly undesirable intruder to any cleanroom environment. The condensate problem aside, cracks or other leaks in insulation are detrimental to maintaining exacting temperatures in cleanroom applications.

Another serious concern about the use of bulky traditional insulation is the possibility of serious worker injuries due to contact with superheated or frigid lines. Ginchereau explains that the greater the congestion of plumbing due to the use of insulation, the greater the potential for injury.

A new breed of insulation

One of the newer materials that provides a new option in cleanroom insulation is a PVDF-based, high-purity foam. This specialty plastic material is a closed-cell foam that in a thickness of only one-quarter inch offers chemical and heat resistance as well as other properties that are equivalent to eight times of what conventional foam provides for cleanroom applications. In other words, one-quarter inch of PVDF-based insulation is equivalent to two inches of open-celled insulation.

In recent years UFP Technologies, Georgetown, Mass., a producer of foam, plastic, and composite products, incorporated the new PVDF technology into an advanced tube and pipe insulation system specifically developed for process lines and equipment in cleanroom environments.

“When you consider that instead of six-inch-plus insulation on dozens of reactor lines, you are adding only one half inch in diameter to a one-inch or two-inch pipe, you can save a lot of real estate,” Ginchereau explains. “In the overall, the insulation is taking up only about one-tenth the space of traditional fiberglass.”

This savings of space translates to many benefits, including reduced cleanroom size requirements. When you consider the space requirements of cleanrooms housing multiple reactors connected to thousands of feet of pipeline with “fat” insulation, the amount of space is dramatically reduced with the use of a “slimmer” product. 

Also, with thinner pipe insulation, more space is available for technicians to access reactors and plumbing, resulting in improved worker productivity as well as less exposure to contact with super-heated or super-cooled lines.

This PVDF-based product offers several other features that render important benefits to operators of manufacturing cleanrooms. The system includes custom-molded coverings for fittings, and an overlapping, self-adhering tape that provides a superior seal. This reduces the possibility of condensate, which can saturate ordinary foam insulation, creating leaks and enabling biological contamination.

Unlike traditional open-cell insulation, this technology does not shed when cut. This means fewer impurity problems while cleanrooms are live, and no need for protective bags and hoods or downtime during installation.

The PVDF-based product doesn’t burn or smoke, which is very important to pharmaceutical cleanrooms where millions of dollars’ worth of drugs could become tainted and lost if exposed to smoke; and it is compliant with Factory Mutual Approvals 4910 standard for cleanroom materials. It has also successfully completed FM’s 4924 Pipe Chase Flammability Test and is rated for use by the semiconductor industry.

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