By Maik W. Jornitz, President, G-CON Manufacturing
Lately, the pharmaceutical industry has become increasingly interested in flexible facilities. There are many reasons why such facilities are needed, for example, for new drug development, or to accommodate changes in process technologies, such as the implementation of single-use process equipment. The move to personalized medicine also dictates construction of more flexible facilities. But there are also purely economic reasons for shifting from traditional to flexible facility designs, not the least of which is the need to reduce costs.
As a result, we are seeing a shift from large, single-product-dedicated brick-and-mortar facilities to multiple versatile facilities including single-use process equipment. But flexible facility designs are often discussed in the same breath as modular designs, and the two terms are not interchangeable - in fact, they aren't even always that closely connected.
In addition to traditional brick-and-mortar facilities, there are alternative facility designs -- for example, modular container, modular stick-built, isolator or containment-based, and autonomous cleanroom POD designs. Most of these are inherently modular, offering advantages over the traditionally built, especially the speed with which they can be built. However, most of the modular designs employ the same HVAC superstructure above the cleanroom area as traditional facility designs. A major constraint to facility flexibility is the HVAC system utilized.
The modularity loses its flexibility as soon as the facility is assembled. Each of these designs has its own purpose, benefits, and disadvantages:
Different designs are often combined in a hybrid design approach.
Questions must be asked before choices are made. What is the purpose of the facility? What are the requirements to fulfill the purpose? The type of facility selected should depend on the particular application or end-user need. A “one size fits all” approach will not make a modern facility more viable.
Although these terms are often used interchangeably, it is important to distinguish between modularity and flexibility. Modular facilities designs are excellent concepts, which, as described above, can be deployed faster than traditional facility layouts. Yet most modular facilities, when completed, become inflexible and very much like traditional facilities. 1
So, how should one define a flexible facility? Flexibility of facilities is often related to two major factors; multi-product processing and scalability. Other factors are mobility and achievable product lifecycles. Processing flexibility is often used in conjunction with single-use equipment technologies. 2
Being the first containment barrier is an advantage the single-use systems represent, which creates the potential flexibility of multi-product processing. However, the reliance here is on the robustness of the single-use processes. If there is a breach, containment duty shifts to the surrounding environment.
In order to maintain flexible production, the surrounding environment must be easily cleanable and sanitizable. This includes the HVAC system, which should also be compact to achieve a validated sanitization process, and is only achievable when the cleanroom space has separate, independent HVAC units, as is the case with cleanroom PODs:
An autonomous cleanroom POD with mechanical room, including the redundant HVAC system
The other part of facility flexibility, scalability, means that processes and facility parts must “flex” with the capacity demands. The facility must be able to increase production capacities quickly if product demand soars and, just as easily, ramp down if demand falls. The process and surrounding environment must be robust but duplicable. One type of facility is not better than another. There are situations where a modular approach will work better and more cost effectively than the POD system. But let's distinguish between the words "flexible" and "modular," and remember that they don't always mean the same thing.