The Cleanroom Construction Process

While there are discrete steps in the design and construction of a cleanroom, those projects deemed successful incorporate certain practices that promote flow of the construction process toward completion on time and within budget. Proper front end planning is not completed until it results in appropriate values for design parameters; "buy-in" at all levels of management, and clear direction for the design phase. Engineering the cleanroom in accordance with recognized industry practice would produce construction documents that facilitate clear procurement and construction planning as well as a focused, efficient, construction effort. A full return on the energy expended through the construction phase cannot be realized without a well-executed start-up and certification process that provides baseline data for effective operation and maintenance. This paper describes the steps in the cleanroom design/construction undertaking and offers practical suggestions on how to avoid pitfalls along the way.


One of the truisms of the construction industry is that the greatest impact on cost of a facility can be made at the earliest stages of the process. The construction process can be likened to a snowball rolling down a snow-covered hill. It grows and gains momentum, seemingly taking on a life of its own, until it can only be brought under control with a major effort. So too with cleanroom projects begins on a well directed course and moves to a successful conclusion.

Sometimes the special nature of cleanrooms clouds the fact that building a cleanroom is in fact a construction project. A facility engineering team may be tempted to turn away from such projects due to their perceived uniqueness and leave the key decision making to others. In fact it is the construction experience of that team that is most required to keep the project costs under control. The way to accomplish this is for the team to be involved in the process from its earliest stages.

Procurement will be purchasing furnishings and process equipment for the cleanroom as well as overseeing the contracts let to the design and construction professionals. Operations people should have input regarding design parameters such as temperature, humidity, lighting, vibration, cleanliness class, and energy usage. Materials handling people should participate in order to understand the requirement for storing raw materials as well as retrieving and storing finished goods from the cleanroom.

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Cleanliness Class

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Energy Usage

An integral part of the front end planning team should be the design professionals charged with developing a cleanroom design based on client input in such a way as to satisfy as many requirements developed in Needs Assessment as possible. This team may be assembled internally but frequently is drawn from specialty builders, A&E firms and design/build firms active in the cleanroom industry. The team of design professionals should have cleanroom experience of facilities comparable in size and complexity to that being planned as well as extensive experience in construction projects of all types. The design team may offer design only, design/build, procurement, construction management or combinations of these services. This design team should be considered a resource during the front end-planning phase. It is the wise client who takes advantage of the experience of the design team, permitting them a large role as facilitators of the planning sessions.

An appropriate design team will demonstrate expertise in contamination control philosophies, space planning, code compliance, mechanical and electrical design, and will be familiar with materials of construction currently being used in cleanroom projects. It is frequently helpful to include a member of the construction team in the front end planning effort to advise on constructability of the facility being planned. Unrealistic construction schedules will be avoided and field rework will be minimized if appropriate attention is paid to the construction phase early in the planning process.


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Preliminary Design

Front end planning typically utilizes expertise of client process people to convey the requirements of the clean facility to the design team. With this information in hand the design team begins the facility design process incorporating process needs, code requirements, safety issues, material and personnel flow, work in process storage, utility needs, etc, into a first cut approach.

Client representative have an opportunity to review the effort and begin fine tuning the design to incorporate late breaking process changes. The preliminary design is a target that helps both the design team and the client solidify design goals. Change is encouraged at this stage and buy-in by all concerned is a major objective of this phase of the design effort.

Let us review the steps in cleanroom construction and identify what should occur at each step and the potential for trouble.

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Needs Assessment

It is during this early stage that a requirement for a clean facility is perceived. The need for a cleanroom may be precipitated by a client indicating that its qualified suppliers must manufacture their product in a clean environment. Perhaps a competitor has begun advertising that their products are produced in a cleanroom. New manufacturing technology may show significant yield improvements if certain operations are done in a particle free environment. Perhaps preventable defects previously accepted by customers are now drawing complaints. There is any number of reasons for upgrading to a clean facility.

At this point a study should be undertaken to determine the benefits to be realized by the new facility as well as the costs to be incurred. Costs arise not only from construction but also ongoing operation and maintenance. IN addition the day to day operation of the facility generally requires that special attire be worn. Also special procedure, frequently more time consuming than those presently used, may be required, It is important that this study is complete and accurate in order to prevent any unrealistic expectations on the part of management and cleanroom end users and to permit planning for revised procedures once the cleanroom is in use.

The study should describe the goals of the cleanroom program. Impact on present operations, budget restraints, tentative schedule, and path forward. It will serve as the basis for front end planning and will provide the standard against which the success of the program is measured.

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Front End Planning

To achieve the required environmental conditions, the air in a cleanroom is purified using High Efficiency Particulate Air (HEPA) filters. Air is forced through the filters, which remove particles as small as 0.5 microns. The filtration system depends upon the required level of cleanliness.

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Construction Document Development

The construction documents should convey the intent of the design team and client to the construction team. A good set of construction documents should result in a tight spread of construction bids as there should be little room for varying interpretation on the part of the potential construction contractors. The documents should have sufficient notes to convey the design intent without creating a cluttered appearance. The written specifications should be as brief as possible consistent with clarity.

Complicated documents create the impression that a project may be more involved, and therefore more costly, than it should be. Cautious contractors may unnecessarily inflate their bid to cover perceived contingencies. Specifications that are too wordy may be difficult to follow and similarly result in higher prices as bidders make sure all bases are covered. No one likes surprises.

The development of construction documents should be a straightforward process with little involvement by the client except to monitor the process and insure that the original design intent is followed. While changes will always occur during this phase, ("cast in stone" is a euphemism for "let's keep the changes under control") they are certainly less costly at this pint than during the construction phase. It is desirable to minimize such changes. A continuous sequence of changes suggests that the preliminary design phase was not entered into seriously. It demonstrates a lack of preparedness on the part of the client and a lack of ability to communicate and draw out the client's needs on the part of the design team. As a sense of clarity of purpose slips away with ongoing change the possibility for errors in construction documents that can surface as costly construction changes increases.

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A detailed scope of work describing the materials and services required is a vital part of the procurement process. There is no purpose to keeping the project bidders in the dark regarding what is required of them. The role of the procurement function is to obtain maximum value, that is, the best quality and schedule at the lowest price. The clearer the scope of work and construction documents the better will be the chance of this happening. A low price is not a good value if the schedule slips by several months as a result. A poorly built cleanroom that does not maintain design conditions is a poor value even if it was delivered within schedule.

The procurement process should qualify potential bidders by insuring that similar cleanroom projects have been delivered on time, within budget and on schedule. References should be checked. It is expected that references offered by a potential bidder would have good things to say about that bidder, but this is not a certainty and pointed questioning about personnel, schedule, quality, change orders, follow-up, etc. can help develop a warm feeling or an uncertain feeling about potential bidders. If bids are in fat quite close it is the quality of references that might suggest a particular bidder be given preference.

There are number of ways in which the cleanroom project can be procured. Use of in-house engineering and construction expertise may work in special situations. Typically problems arise when facilities departments, stretched to their limit with ongoing plant requirements, must lower the priority of the cleanroom to meet other commitments. The schedules may stretch out unacceptably.

Modular cleanroom manufacturers and specialty contractors have proven over the years to be adept at installing small turnkey facilities of limited complexity in a timely and economical fashion. If extensive engineering is required, if local code compliance becomes an issue, if complex process requirements must be met, or if the client requirements exceed the experience of the supplier there could be cause for concern.

Design/build is a popular approach in that it suggests a single source of responsibility for all phases of the project. Frequently firms billing themselves as "design/build" are strong in either design or build, but not both. The strong design firm can put the essentials on paper but final price and schedule may suffer. The strong design firm can put the essentials on paper but final price and schedule may suffer. The strong construction firm may lack the expertise to create a clean environment, particularly in the Class 10 or cleaner regime. The project may be outstanding in all respects except performance. A good review of references is essential before selecting a firm in this category.

Construction management has been increasingly used on larger projects. A good construction management firm will work closely with the client selected engineering company to review constructibility and adequacy if construction documents. It will assist to qualify bidder, maintain schedule, track costs, administer and oversee, and generally insure that a team incorporating the strongest skills is assembled to complete the project. Cleanroom experience is essential.

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The construction process should proceed smoothly if the remarks presented about are followed. Cost can increase during this phase if changes must be implemented. While change is inevitable a construction change procedure, negotiated during the bidding phase and in place during construction, will keep such change form getting out of control.

The requirement for "building clean" has arisen in recent years as Class 10 and Class 1 cleanrooms have become more popular. Imposing cleanroom construction protocol should be developed during the construction document phase and be an integral part of the bid documents. Once the decision is made to work clean strict protocols should be followed by everyone on the jobsite associated with the clean areas. A poorly conceived and enforced protocol will be a costly and futile exercise. The tendency to "build clean" on every cleanroom project should be resisted as only the most stringent cleanrooms will benefit from such a protocol.

Client cleanroom end users should be encouraged to observe construction as it progresses. They will be more intelligent about how cleanroom components go together and therefore more attuned to maintaining the facility once it is completed and in operation. While suggestions should be welcomed as construction progresses it is important that a chain of command be enforced. Any questions or suggestions or concerns should not be expressed to workers on the site but rather through management channels. In this way good ideas can be implemented and bad ideas shelved without impacting the construction effort in a negative manner. Note the one exception to this practice is in regard to safety. Everyone on the site has safety responsibility. Any unsafe acts should be questioned and supervisors consulted immediately.

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Start-Up & Certification

Subcontractors on the jobsite should be responsible for start-up as well as installation of equipment. If several trades are involved in a particular piece of equipment then one trade should be assigned, by contract, as having coordinating responsibility, for that piece of equipment. This will minimize "finger pointing' when equipment does not start or operate properly. This can be a sensitive issue and a construction manager can set the tone for cooperation in this area.

An independent contractor responsible to the construction manager or owner should do testing and balancing (TAB) of mechanical systems. All start-up should be complete and initial valve or damper settings made by the subcontractor before testing and balancing begins. The TAB contractor should not have to repair equipment or troubleshoot inoperative equipment but rather only adjust and verify performance of equipment.

A separate contractor should certify the cleanroom, possibly the TAB contractor if that firm is suitably qualified. There should be no question of equipment being operative at this stage of the project since start up and testing and balancing are complete. Certification is the verification of facility compliance with cleanroom specifications. If the facility design is well conceived and the construction team has installed a quality project any certification test failure will most likely be corrected through fairly minor adjustments. Failure of the cleanroom to pass certification tests might require redesign, but more frequently requires some equipment adjustment, or perhaps a filter repair, and then a retest. It is important that a clear understanding of responsibility be communicated before problems are encountered. Failure to plan for potential problems could result in extending the schedule and incurring unforeseen costs at a crucial point in the project.

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Recognizing the step by step process involved in even the smallest cleanroom project can help focus attention in a manner that will result in a successful project. The schedule of a well-conceived project will include needs assessment, front-end planning and preliminary design. It is important that project progress is measured against an overall schedule and not just by the speed with which the bricks and mortar are installed.

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