Retrofit 101: Get the balance right
10/01/2001
by Thomas E. Hansz, AIA
TIME, SAFETY AND CONTROL ARE THE KEYS TO SUCCESS
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The key words for cleanroom retrofitting are time, safety and control. Time is of the essence, safety is always a prime concern, but it's the control of the project that's the most difficult to maintain.
Whether it's to increase capacity, improve productivity or to advance to a new level of technology, retrofit construction projects are extremely time sensitive. Short duration design and construction activities may be required to meet one or several of these retrofit objectives: minimize loss of production time; meet a business milestone; minimize the effect upon cleanroom processes; and minimize the effect upon cleanroom employees.
However, the emphasis on time does not diminish other major concerns of cleanroom construction, namely: construction and operational safety; construction and process contamination control; and cost control accuracy.
Reduced time durations force the cleanroom owner, designer and builder to focus on a collective, coordinated and controlled team approach. A collective approach is required because the normal, linear series of design and construction activities—the 1,2,3 process—requires more time from start to finish.
For retrofit projects, however, the process is a dynamic one. Assembling the project team simultaneously will save significant time and may even result in serendipitous benefits. The key is to bring the in-house personnel, architect/ engineer (A/E) and the contractor together at the start of programming.
Fast-track team approach
A fast-track team approach forces owners to understand the critical nature of design and construction-related decisions and how to prioritize them chronologically. Decisions on process equipment and utilities can be scheduled concurrently with the design activities. Quantities can be estimated with certain risk factors applied and modified as the design time allows. The tool list and utility matrix can be developed at the same time that existing conditions are verified and documented.
As the A/E works with the user to develop process flow and utility requirements, the contractor can develop the construction strategy, which in turn becomes a design element. The cleanroom floor plan is developed to accommodate a short-term construction process and helps define changes to the existing systems. The resulting design is both efficient to operate and timely to build. Not only is a possible redesign avoided, but the contractor possesses a working knowledge of the design from the beginning.
Having all team players on board at the start also provides the greatest amount of lead time to plan construction activities that could affect cleanroom operations. This reduces the potential for surprise during the retrofit. Tapping into existing power lines and process utilities will invariably have an impact on operations. If necessary, uninterrupted utilities can be provided with temporary chillers, fans, pumps, generators or temporary systems. Combined planning will allow users to treat the changeovers as scheduled down times so the effect on the process is minimal, or non-existent.
Having the contractor work with the A/E also makes it possible to base the cleanroom design on products and equipment that are available. The A/E establishes the criteria, the contractor determines the availability, and the subsequent trade-offs are discussed with the owner.
Safety is a priority
Whether a cleanroom retrofit is for a life science or microelectronics facility, the production process usually involves hazardous materials, chemicals or gases. Reviewing the HPM inventory and the proposed process changes is a critical step. While the A/E develops the utility matrix, the contractor can be developing the construction safety program. Connections to existing bulk delivery systems or waste systems can be examined and modifications agreed upon before the design is complete.
If new tools or equipment are being installed in the cleanroom it can be tempting to shoe-horn them into tight spaces. Recommended access space and emergency egress space should not be overlooked. The idea of saving on construction costs today at the risk of jeopardizing a worker's safety tomorrow has no place in retrofitting a cleanroom.
The critical elements of a cleanroom retrofit, by their very nature, oppose each other. Short construction durations tend to raise labor and shipping costs. Confined work conditions not only tend to raise labor costs but can present marginal safety conditions. The emphasis on reducing time durations can make short cuts look attractive; however, while it may be tempting to focus on time and costs, safety has to be a priority of equal standing.
Contamination control
It is not unusual for owners to allocate space for the retrofit work and forget the space required for clean construction staging. Before the design begins, the A/E and contractor can determine if there is enough space for construction activities such as clean storage, wipe-down space and construction personnel gowning. Clean construction staging may require 10 to 20 percent additional space depending upon the size and nature of the cleanroom. Unnecessary handling of materials and equipment increases the possibility that materials may become contaminated or possibly damaged.
Having this contamination-controlled staging space is a major element in the clean construction protocol program. Not only will it service the retrofit work, it can also prevent the existing contamination-control level from being compromised. Managing lay-down and storage space for clean construction materials and components will reduce labor costs and the potential for excessive contamination generation.
While temporary clean staging space is not expensive from a construction perspective, it may be expensive from an available space standpoint. Even in facilities where floor space is at a premium, a compromise on this essential space can easily result in devastating compromises to the overall contamination control program.
Along with this temporary clean space, clean construction protocols should be developed during the design process—another good reason for hiring the A/E and the contractor at the same time. The operational protocols will reflect the clean construction protocols. Any unusual requirement can be identified early and the construction budget adjusted accordingly.
Cost control accuracy
Modifying existing, functioning cleanrooms makes retrofit projects the most expensive type of project on a per-unit basis. Having an accurate and thorough budget from the start is essential for project success.
Four of the more common mistakes made in establishing budgets for cleanroom retrofit projects include: relying on unit costs from other cleanroom construction projects, underestimating spare capacities in existing systems, assuming that "as-built" documents are not required, and viewing the retrofit in isolation from the context of the existing facilities.
Unit costs, such as dollars per square foot or per cubic foot per minute (CFM), are not easily transferred from project to project. Retrofit work is process, facility and calendar specific. What may have been true on other retrofits will most likely not be true on your project. Unit costs for systems may vary as much as 80 percent between retrofit projects and new construction.
Too often retrofits are started assuming that existing utilities—electrical power, chilled water, process exhausts—will adequately accommodate the retrofit requirements. Not having accurate "as-built" documents and up-to-date maintenance records can seriously derail a retrofit budget. Before determining how much the retrofit will cost, the current capacities, as well as existing interstitial space conditions, should be examined.
Planning the retrofit project
At the start of planning to retrofit portions of the cleanroom and before the budget has been finalized, ask some of the following questions:
- Do existing architectural, structural, mechanical, electrical and high purity piping drawings accurately document the current conditions of each system?
- Do existing utility loops and equipment meet spec, and/or governmental regulations, or are they outdated and should be replaced?
- Does the lack of interference with existing operations justify the added expense of second shift construction work?
- How will the project team deal with change? (Change in scope; change from unforeseen conditions; or change from equipment availability and lead times.)
- What is included in the project budget and is the contingency amount adequate?
If answers to these questions are not readily available, the questions at least will raise some flags. In turn, having such open issues should result in increasing the contingency within the retrofit budget until the answers are known. Forming questions like these early in the retrofit work will keep the number of surprises low and the budget on target.
Thomas E. Hansz, AIA, is president of Facility Planning & Resources, Inc.(FPR) a cleanroom planning, design and construction firm located in Pittsburgh. Hansz is a member of the Cleanrooms Editorial Advisory Board.