Thinking clean
Cleanroom cleaning & maintenance: An enigma wrapped in a riddle

by Mark A. DeSorbo

Click here to enlarge image

Cleanroom cleaning & maintenance:
An enigma wrapped in a riddle

Let's face it: The personnel in charge of grounds keeping or mopping the bathrooms are not going to make a dent in most company revenues, but whoever is responsible for cleaning and maintaining the cleanrooms can make all the difference in the world to a manufacturer that is ultimately trying to stay on par or leave their competitors in the proverbial dust.

The science of cleanroom cleaning and maintenance can indeed be an enigma peppered with formulas, procedures, equipment, chemicals, applications and schedules—all inside a virtual maze of spotless white walls.

It is within these corridors where, perhaps, the greatest concern to those who follow the contamination control creed lies: The effectiveness and the application of the cleaning process.

“The cleanrooms marketplace is really maturing and there is a much greater awareness today than there was even five years ago,” says Ian M. Wallis, president of Microcomplete Inc., a Wilmington, MA-based cleanroom cleaning services provider.

The dirt
Visual inspection for contamination is futile, and questions on what, how and when to clean abound. Despite even the most meticulous efforts to rid the controlled environment of microorganisms or particles, the chosen cleaning method may not be enough.

Click here to enlarge image

“Unless you've worked in a clean space, it's hard to comprehend what's involved,” says Richard Matthews, technical director at Filtration Technology Inc. (Greensboro, NC) and a CleanRooms Editorial Advisory Board member.

Chesapeake Biological Laboratories Inc. (Baltimore), for example, gave itself a clinic when it launched a comprehensive cleaning for its facility near Camden Yards. Although ISO Class 5 and 6 (Class 100 and 1000) as well as ISO Class 7 and 8 (Class 10,000 and 100,000) cleanrooms were broom and vacuum cleaned and chemically washed and rinsed, microorganisms like mold spores were still found in verification tests. To rid the areas of contamination, Chesapeake cleaned again using helpful documentation it collected before the initial disinfection, and then instituted daily and weekly cleaning schedules in order to combat contamination. (See “Bacteria Busters,” CleanRooms, February 2000, p.1.)

The IEST recommends that the horizontal surfaces of lighting units be vacuumed with a soft brush attachment. Wipe surfaces of egg crate light diffusers with a wiper dampened with DI water. Open unit, wipe bulbs and vacuum horizontal surfaces with soft brush attachment. Close unit. Wipe trim pieces.
Click here to enlarge image

Aside from the complexity of the science surrounding it, Matthews says there are many wrenches thrown in the works, from apathetic personnel to cross-contamination that can occur if a maintenance worker happens to use the same tools to work on a machine in an environment where penicillin is prepared as he did to fix a tool in a cleanroom where aspirin is made.

There are even situations where the upper management of a company does not understand the importance of cleaning and maintenance, or there is a complete absence of cleanroom managers to handle the task, observes Janice Baker, an independent cleaning consultant with Creative EnterpriZes, which has offices in Big Fork, MN, and Jackson, TX.

Finding the person or persons in charge of cleanroom maintenance can be difficult these days, for the position, especially in the semiconductor arena, was a casualty of downturns. If such an individual or staff exists, they may not be empowered by upper-level management. “The person who is put in charge of the cleaning may not be enabled by upper management to make a difference,” Baker says.

Plus, a purchasing department may not necessarily understand the ramifications of a specific cleanroom-grade product order. A cleanrooms facilities manager, for example, might ask for “brand-x” wiper, but the purchasing agent may order “brand-z” to save money and end up with a source of contamination that could take months to discover.

“There are so many variables involved in cleaning and maintenance,” Baker says. “I was in an ISO Class 6 cleanroom where someone brought in a box of powdered gloves. It caused problems that took weeks to correct.”

Moreover, establishing a cleaning protocol can be difficult for contract manufacturers with customer needs being ever-changing. “The requirements of the customer are changing faster than the vendors can keep up with,” she adds. “For example, automotive components change annually. It takes months to reconfigure and get a production line up and running. One change can set everything back for months.”

Click here to enlarge image

Walls should first be vacuumed with a soft brush attachment, according to IEST recommended practices. Wipe with a wiper dampened in a solution of DI water and a commercial cleaning detergent. Wipe in one direction only using slight overlapping strokes. Mop entire surface with a commercial wall cleaning system. Mop from top to bottom using slightly overlapping strokes. Use a minimum of liquid to avoid splashing or dripping. Tack roll from top to bottom. Remove spots with a commercial cleaner and woven polyester wipe, and then vacuum with a soft-brush attachment.

Many standards organizations, namely the International Organization for Standardization (ISO; Geneva) as well as the Institute of Environmental Science and Technology (IEST; Mount Prospect, IL) has reached out to those needing guidance in the cleanroom housekeeping arena.

ISO 14644, a global cleanroom protocol that will ultimately sunset Fed-Std 209E, offers cutting-edge guidance. Within it is document ISO 14644-5 “Cleanroom Operations,” which addresses several major areas, one of which deals directly with cleanroom cleaning and maintenance. [See “Maintaining the cleanliness of a cleanroom,” CleanRooms, August 2000, p. 43]

“[The document] is a good baseline and it covers all the aspects of good cleanroom housekeeping. It requires someone who knows what they are doing, to know that you don't clean your house or your desk the same way,” Matthews adds, referring to his August column. “It's how you vacuum. Can you wet-clean? Do you clean overhead? This document would show you how to do the job.”

Management and personnel training
Echoed throughout IEST recommended practices as well as ISO 14644-5, which is in the Draft International Standard vote phase, is the need for management and personnel training, key components in maintaining the cleanliness. Equally important is ensuring cleanroom personnel adhere to the protocol.

“Training is key, but rather than just train them, they need to understand the sensitivity of the cleanroom, the product and the contamination that hurts the product,” says Wallis, a member of the IEST Working Group 18, “Cleanroom Housekeeping—Operating and Monitoring Procedures.” “They need to understand they are an important part in the production of successful, clean, quality products.”

And that means cleanroom personnel must adhere to the house rules, and even the not-so-cleanroom-saavy know at least some of them: Don't unzip your gown if you're warm; Don't wear larger garments so you'll be more comfortable; Don't wear make-up in the cleanroom.

Whether it is a maintenance staff or a single auditor, Wallis recommends using a Parado chart. The auditing device enables a cleanroom manager to observe functions and identify breeches in the protocol. “It's a useful tool in helping to label a particular job function that you want to assess for training effectiveness and quantify required protocols,” he says, adding that a Parado chart is not meant to be a vehicle to hand out slaps on the wrist.

But sometimes, the end-user just doesn't understand the importance or even care what the rules are. “One person not following rules and regulations is the rotten apple in the barrel. He or she can kill everything you're trying to do with sloppy habits,” Matthews adds.

The precepts of IEST recommended practices, ISO standards as well as current good manufacturing practices (cGMPs) are excellent tools to carry forward and apply to any cleanroom, says Neil Kindness, president of Critical Cleaning Technology (Crofton, MD), which, like Microcomplete, has recently become a division of Crothall Specialty Services.

While recommended practices and standards are used to draft standard operating procedures (SOPs), some SOPs fall short of meeting the goals.

“Often, we encounter poorly written SOPs or poorly written clauses within them. It's very easy for us to identify them because they are typically not specific enough,” Kindness says. “One customer's SOP said 'The room shall be cleaned on a regular basis.' Another's says 'Use the appropriate disinfectant when cleaning.'”

Therein lies the conundrum of the SOP, it can be too general and too specific.

Furthermore, Kindness says aesthetics are important. “If the windows are streaked and the walls are streaked, the personnel will begin to think they no longer need to be careful.”

Getting with the program
As a preventative measure to maintain cleanliness and market viability, contamination control managers must be in place, and serve ultimately as librarians of an established cleaning program, says Larry Mainers, vice president of Pentagon Technologies (Freemont, CA) and founder and president of TEC International, which has been providing contamination control services for cleanrooms since 1985.

An ideal program, he says, should include effective cleaning procedures; a list of approved cleaning equipment, tools, wipers and chemicals with designated dilution rates; safety procedures; protocol instructions; product production information; shift schedules; and specific certifications for certain duties.

“Our people have determined the best ways to clean and how often from our internal database,” Mainers says of Pentagon, a recently formed conglomerate of five contamination control companies.

Effective cleaning, he explains, does depend on surface cleaning with wipers, all the while not limiting movement within airflow path. Equally important is proper mixture of chemicals and deionized water to the wiper, the basis of absorption.

Not enough liquid and particulate absorption will be hindered and also cause abrasion from one dry surface to another. Too much liquid will leave residue that store contamination.

Click here to enlarge image

Mainers likens typical cleanroom cleaning to running a car through an automated washer. What comes out at the end of the garage bay looks like a shiny new car, but upon closer inspection, the paint has taken a beating.

The same can be said, he explains, for cleanroom cleaning. The wiping, the vacuuming, and the chemicals can take their toll on the cleanroom walls and surfaces.

“People who have been trained to clean what is visible do not understand the other intricacies. Inappropriate action can damage the environment,” Mainers says. “What is also important is cleanliness of the facility around the tool, cleanliness of the air and then the actual cleanliness of the parts inside the tool. The combination of those three will have a predictable result, which [the tool] will not go down due to particle contamination.”

The nitty gritty
When, where and what to clean all depend on the application. Wallis, whose knowledge has been recorded in the pages of CleanRooms magazine, notes that the IEST preferred cleanroom-cleaning protocol is summed up in three words: vacuum, wipe, vacuum.

Vacuuming captures loose particles, and wiping scours contamination rooted to surfaces. Subsequent vacuuming picks up the remaining contamination and residue from cleaning solutions.

The IEST recommends that floors be vacuumed first, and then mopped with a solution of DI water and a commercial floor cleanser with a clean, non-contaminating mop head. Rinse with DI water. The rinse water should be left on long enough to saturate any film build-up and then mopped with a new, clean, non-contaminating mop head.
Click here to enlarge image

The basic tools of the trade are not hard to figure out: Vacuums, wipers, mops and cleaning solutions, namely isopropyl rubbing alcohol and deionized water that are coupled with multipurpose cleaning solutions. [See “Decontaminating the cleanroom requires good science,” CleanRooms, July 1997].

Like Wallis, Mainers has also written articles on cleanroom cleaning. Before actual cleaning starts, he says another key to the process is inspecting and auditing before and after the cleaning process. “Unlike the case with the IRS, you will be glad to have this regular update to keep you informed, honestly, as to the effectiveness of your contamination control program,” he writes. [See “There's more to cleaning cleanrooms than meets the eye,” CleanRooms, July 1999].

Other writers, like CleanRooms Columnist Matthews stress the common sense of it all. While discussing the parameters of ISO 14544-5 and the housekeeping baseline it provides, he had this to say: “The irony is there are companies that spend upwards of $500 a square foot for ISO 5 clean space, and jeopardize it with untrained personnel. It's suicidal.”

Photos courtesy of Pentagon Technologies (Fremont, CA).


Easily post a comment below using your Linkedin, Twitter, Google or Facebook account. Comments won't automatically be posted to your social media accounts unless you select to share.