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Variables ImpactingCleanroom Constructionby Blake HodessW H I T E PA P E R

CONTENTSIntroduction. 3How to Select a Cleanroom Development Team. 3What Your Cleanroom Team Should Do. 3How Variables Impact Your Process & the Type of Cleanroom Needed. 3Cleanliness Level. 3Temperature. 4Humidity Control. 4Sound Level. 4Vibration Control. 4Static Dissipation. 4Return on Investment. 4Cover All the Bases. 5For More InformationIf you have questions or want more information,please contact us.Hodess Cleanroom Construction100 John L. Dietsch SquareNorth Attleboro, MA 02763Phone: 508-695-1012Fax: 508-695-3101Email: [email protected] our website at hodesscleanrooms.comAbout Blake HodessPresident of Hodess Construction Corporation, Blake G.Hodess offers over 40 years of construction experience.Blake is highly recognized in the industry for his expertise incleanrooms and advanced technology construction. He hasvast experience in all project responsibilities throughout theconstruction process, as well as cleanroom construction.A published author, Blake has been featured in numeroustrade journals and has guest lectured on the design-build ofcleanroom projects.Hodess Cleanroom Construction has consistently rankedamong the ENR Top 600 Specialty Contractors. It is thecompany’s initiative to create and build successful and highquality facilities for clients and the cleanroom industry.Blake believes that the continuous focus and dedication totheir clients directly relates to the company’s success.

VA R I A B L E S I M PA C T I N GCLEANROOM CONSTRUCTIONBY BLAKE HODESSOnce you’ve made the decision to build a cleanroom,what happens next? Examining variables that are required foryour cleanroom is step one. However, you need to understandhow these variables affect your manufacturing process. Everyprocess is different. Your individual process needs must beexamined thoroughly.This article discusses why and how variables can impactcleanroom construction. The task is to perform an in-depthanalysis of these variables as they relate to your manufacturingprocesses because they will drive your cleanroom design andconstruction decision-making.HOW TO SELECT A CLEANROOM DEVELOPMENT TEAMThe first step is to form a cleanroom development teamcomprised of key internal staff and external consultants thatcan help analyze needs, as well as design and build the typeof cleanroom you need.Internal cleanroom development team members shouldinclude individuals who know your process best and know howthe different variables impact your manufacturing procedures.External cleanroom development team members are oftendesigners, builders, manufacturers of cleanroom systems,and/or a combination of disciplines rolled into one entity.To identify external cleanroom development team membersthat may be helpful to you, contact associates, clientand friendly competitors in your industry. Ask them forreferrals on designers, builders and manufacturers thathave successfully provided cleanroom expertise in yourindustry or similar industries.WHAT YOUR CLEANROOM TEAM SHOULD DOThe first task for the cleanroom development team isdetermining what variables and how each variable impactsyour manufacturing process. Critical variables that should beexamined include: cleanliness level, temperature, humidity,sound level, vibration control and static control. To helpidentify these variables, the amount of work and a potentiallayout of your process work flow need to be communicated tothe development team.A walk-through of existing facilities and a review of theactual process are critical and should be requested by thecleanroom development team initially as an immediate needfor understanding and ensuring that final requirements aremet. Be leery of cleanroom entities that assume they knowyour process. Be cautious in applying standard or pre-manufactured, non-customized technologies. You can end up withmore cleanroom that you require, an inappropriate cleanroomclassification, or a cleanroom layout that is not complementaryto your process. The cleanroom environment is another tool tohelp increase the manufacturing yield. It should be considereda tool and not an end in itself.Full integration of the cleanroom as a tool is the primaryobjective for initial discussions and setting the goals requiredfor the cleanroom development team. The team should usea list of the variables as well as a survey form to review theprimary objectives and utilization of the room.HOW VARIABLES IMPACT YOUR PROCESS AND THE TYPE OFCLEANROOM NEEDEDCleanliness Level. Cleanrooms are classified by cleanlinesslevel. ISO 14644 gives testing and certification procedures andrequirements for designing and classifying a room. This involvesreviewing the types of filtration to be supplied on both outsideand recirculated air and should, in today’s environment, alsoinvolve a review of chemical and airborne biological filtrationrequirements. Some areas of manufacturing will requireextensive re-filtration of outside air and recirculated air andothers will not. Classification of the room should be basedon the potential for contaminate destruction of the end useproduct. An ISO 3 cleanroom at 0.12 microns may be applicableto a process such as submicron semiconductor manufacturing,but may be overkill for the plastic molding industry, filmindustry and others.3

Temperature. A review of the effectivetemperature on the end use product iscritical. The HVAC systems involved incleanroom construction can run up to60 percent or greater of the totalconstruction cost. The temperatureand humidity requirements can drivethe operating and initial installationcost. If the project is a renovation oraddition to an existing plant, a surveyshould be conducted regarding theability to reuse features of the existingbuilding to minimize temperature,humidity and HVAC requirements.Under new construction procedures,a review of the various types of systemsavailable should be conducted to makesure that the owner is getting theoptimum operating cost and initialfirst cost systems available to meetthe temperature requirements aspredicated by the process.Humidity Control. There are two sidesto the humidification requirement.Each may affect process and staticcontrol. Humidification can beaccomplished by many means includingsteam, ultrasonic, electronic, cleansteam, cold water vaporization andevaporation. The way humidificationis generated for winter conditions anddry climate conditions needs to beconsidered relative to its potentialcontamination issues and energy use.Often the humidification procedurecan be combined with the heating inone process, or it be may be coupledwith the creation of purified water fora process such as deionized water.Humidification needs to be reviewedto ensure that the humidifiers areselected and installed properly, and thatproper absorption temperatures andspaces are provided in the HVAC systemsto ensure that future maintenance andfallout issues do not occur.Dehumidification is typically a resultof the air conditioning process usedin cleanrooms. Sometimes additioaldehumidification may be requiredabove and beyond what the operatingtemperature will derive during hotand humid times of the year. Thedesign condition and requirementfor operational conditions must bediscussed early in the project.4Dehumidification can involve evenmorestringent and expensive applications ofHVAC equipment if relative humidityneeds to be driven below 38 percentfor normal operations. At this stagedesiccant dehumidification needs tobe reviewed as applicable to theprocess. Desiccant adds to both capitaland operating costs but may increaseyield and may be necessary dependingon your particular process.Sound Level. Sound level can affectboth performance in the fab, workercomfort, and vibration throughairborne sound waves. The review ofthe sound requirements must be doneat an early stage. Effects of processexhaust and process equipment soundlevels should be reviewed thoroughly.There is no sense spending a lot ofmoney to achieve a low sound level,if the background level of processexhaust and process equipmentoperations will be in excess of this.The key is to balance the sound levelprovided by the clean room system.The sound level should not exceedand not add to the sound level providedby the process and/or process exhaustsystems.Vibration Control. Vibration controlcan be a critical issue for somemanufacturing operations and a nonissue for others. In the semiconductorindustry, vibration control can becritical to the photolithographyoperations. In other manufacturingsituations, such as biotechnology,pharmaceutical, plastics, circuit boardsand others, this does not appear to bethe case. Although vibration should beminimized in accordance with standardgood HVAC practices, excessive fundingis not necessary to dampen or removevibration in many facilities. Whenvibration does need to be considered,the cleanroom development teamshould suggest the use of an outsideconsultant.Static Dissipation. Many processesrequire eliminating static due toits disruption of the manufacturingprocedure. In some particularindustries, such as the semiconductorindustry, static dissipation and staticbuildup are extremely important issues.Cleanrooms tend to build up static ifnot properly treated. Treatmentcan occur through the selection ofbuilding materials and through thehumidification process.Discussing how to deal with staticis critical at the beginning of yourcleanroom project to not only ensurethat products selected for constructiondo not increase static, but also toconsider the selection of products thatcan dissipate static.Return on Investment. The discussionof return on investment is a criticalone at the beginning of a project. Manyprojects are designed to increase yield,but some projects are also designed toincrease sales. If your objective is togenerate additional income and salesthen the cleanroom may need to behighlighted and accentuated with theuse of viewing windows and visual aidssuch as computerized pressure readings,particle monitoring systems, andtemperature and humidity trackingsystems. These features can help youverify for your clients the current andcontinuous operations in your facility,demonstrating that your quality controlis as stringent as your clients’ needsrequire.CONTINUED