Facility Design Issues for Single-Use Processes

Single-use technology is a proven alternative to traditional stainless-steel vessel and pipe bioprocessing. Available for all stages of processing, from media prep and upstream operations to buffers and downstream processing, single-use systems (also known as disposables) are found in licensed biopharmaceutical manufacturing facilities around the world. The most common applications today are hybrid systems combining both disposable and traditional stainless-steel unit operations. Most importantly, single-use connectors, sampling, and transfer systems provide for truly closed processes.  

Cleanroom classification

Being a closed process by itself represents savings over traditional fixed systems. The most obvious is the downgrading that can be achieved in cleanroom classification of the process spaces. An open process that would typically require Grade B space can now be Grade C or perhaps even lower. With each higher grade of classification, a greater number of air changes is required with a corresponding greater operational cost per square foot. As a result, reducing the classification of a space provides operational savings that continues year after year. In addition, downgrading space classifications can reduce or even eliminate the gowning rooms and airlocks that are needed to transition to those higher classifications. Every time gowning and airlocks are removed, savings accrue from a broad range of reductions, including gowning supplies, gowning time and labor, material transfer time and labor, cleaning supplies and labor, and environmental testing. From an operational perspective, these accumulate over time and provide opportunity for greater productivity.

Cleaning requirements

If thoughtfully designed, stainless-steel process trains can also be closed operations. However, non-disposable equipment requires maintenance, especially cleaning between batches. With stainless steel, this is achieved through robust clean-in-place, sanitization-in-place (CIP/SIP) systems. In contrast, single-use technology is simply disposed of. It eliminates the need for CIP/SIP and all that goes with it. The equipment, piping, and space that houses CIP/SIP tanks and pumps are no longer needed. There is a reduced burden on the utilities supporting the system, and the need for purified water, water-for-injection (WFI), or clean steam is eliminated, at least as far as CIP/SIP is concerned. CIP requires a tremendous amount of water. The elimination of its use is environmentally friendly, and there is no need for cleaning chemicals. The elimination of CIP/SIP and its supporting utilities simplifies facility design in many ways, reduces energy use, and has a corresponding reduction in capital and operational costs.

Handling disposables

Although single-use technologies can reduce the amount of cleanroom production space and associated technical support requirements, single-use technologies also increase the amount of consumables that are handled. Single-use bag and tube sets need to be stored before use, and these same items need to be deactivated and staged for disposal after use. Even with sophisticated just-in-time receiving and shipping technologies, the space implications must be addressed. Increased warehousing and space dedicated to deactivating and staging of the used disposables must be accommodated. Although these unique space needs are added requirements, their capital and operational costs are significantly lower than the higher-grade GMP process spaces demanded by stainless steel.

The disposal of single-use technologies raises obvious concerns regarding its environmental impact. The materials are plastic, which the public typically associates with being non-sustainable. This concern, along with the continual waste generated, presents the obvious question regarding sustainability. But sustainability can be a complex question and requires a lifecycle assessment to provide a comprehensive answer. Single-use technology presents pluses and minuses on both sides. The production, distribution, and disposal of components generates potentially significant amounts of waste; however, it also reduces the generation of large quantities of WFI, process water, and steam. In fact, numerous studies have shown some environmentally beneficial aspects of single-use (1–3). In a comprehensive lifecycle assessment study reported in BioPharm International, it was found that “single-use process technology can have less impact on the environment than traditional process technology in a broad range of environmental impact categories … in this study, single-use process technology exhibited lower environmental impact compared to traditional process technology in all midpoint and endpoint damage categories that were considered” (4). The conclusion drawn is that compared to stainless steel, single-use systems are sustainable.

Conclusion

The implementation of single-use technology in a facility has important differences from traditional, fixed stainless-steel installations. These changes, however, are not extreme; overall, they are more about the shifting of space and cost from one area to another. There are shifts in the configuration of spaces as well as shifts in capital and operational costs. Expensive classified cleanroom spaces can be reduced, but inexpensive storage space is increased; there is an increased cost for consumables but reduced turnaround time between batches; and there is an overall increase in production time compared to the labor expended. Despite these realignments, a consistent picture emerges that the savings are many, especially with the elimination of CIP/SIP. The consensus has developed that single-use systems save both capital and operational costs over fixed stainless steel. Although a facility with single-use technology in all its unit operations returns the most savings, savings are possible even with hybrid facilities. As companies experience these unit savings it seems natural that pressure will build for more, and more complete implementation of single-use systems.

References

1. A. Brown, et al. “An Environmental Life Cycle Assessment Comparing Single-Use and Conventional Process Technology” BioPharm Int. (Nov. 2, 2011), www.biopharminternational.com/environmental-life-cycle-assessment-comparing-single-use-and-conventional-process-technology, accessed April 25, 2017.
2. H.L. Levine, et al. “Efficient, Flexible Facilities for the 21st Century” BioProcess Int. (Dec. 1, 2012), www.bioprocessintl.com/manufacturing/facility-design-engineering/efficient-flexible-facilities-for-the-21st-century-337813/, accessed April 25, 2017.
3. C. Scott and W. Whitford. “Single-Use and Sustainability” BioProcess Int. (April 1, 2014), www.bioprocessintl.com/2014/single-use-and-sustainability-351059, accessed April 25, 2017.
4. M. Pietrzykowski, et al. “An Environmental Lifecycle Assessment of Single-Use and Conventional Process Technology: Comprehensive Environmental Impacts” BioPharm Int. (March 1, 2014), www.biopharminternational.com/environmental-lifecycle-assessment-single-use-and-conventional-process-technology-comprehensive-envi, accessed April 25, 2017.

Article DetailsPharmaceutical Technology
Vol. 41, No. 6
Pages: 42–43

Citation:
When referring to this article, please cite it as E. Bohn, "Facility Design Issues for Single-Use Processes," Pharmaceutical Technology 41 (6) 2017.

About the Author
Eric Bohn is partner at JacobsWyper Architects, 1232 Chancellor St., Philadelphia, PA 19107,  tel: 215.985.0400, www.jacobswyper.com.