In the disposable case, because the demand to operate equipment cleaning and sterilization activities is significantly reduced,
the labor required to support such tasks decreases. The disposables-engineered facility also may reduce labor requirements
in other areas, such as quality. The set-up and turnaround time for disposable systems typically is shorter than for their
stainless steel counterparts. All these factors result in a less labor-intensive facility. There is an overall 21% reduction
in labor headcount in the disposables-based option compared to the traditional stainless steel–equipped facility. The bulk
of the savings in labor headcount is derived from reduced clean-in-place (CIP) activities (Figure 2).
Space
Figure 3
The disposables-engineered facility simplifies hardware installation, design, and storage, leading to more efficient use of
space and thus considerably reducing the square footage of the facility. Figure 3 illustrates the facility footprint in square
meters for the various area classifications. Table 4 lists the amount of floor space needed in each area classification, based
on the types of activities that take place in each. Because the two manufacturing options have the same inoculum preparation
and downstream purification sequences, which take place in Class B and C areas, respectively, the floor spaces required for
those two classes are the same in both instances. The savings in floor space are obtained from Classes D and U, where the
cell culture, solution preparation operations, and utilities equipment are located, with the majority of the space savings
coming from Class D. It can be seen that the facilities footprint of the disposables facility is reduced by 243.19 m2, or 38%, compared to the traditional facility.
Electricity
Table 4. HVAC energy consumption for each class of facility space. The disposables-based facility uses 38% less floor space
in Class D and U areas, and as a result, the total energy consumption for HVAC is 29% lower in that setup. overall in the
disposables facility.
As a result of its smaller facility footprint, the disposables-based facility achieves process electrical savings of about
30%, indicating that such a plant is potentially more energy-efficient. The cubic feet per minute/kilowatt (cfm/kW) values
for each class are listed in Table 4. Because the energy required to operate HVAC systems is directly proportional to the
floor area, the electricity required to operate classes B and C is the same in the stainless-steel and disposables-based facilities.
In the disposables-based facility, however, the total electricity consumed for HVAC operations is reduced by about 29%, which
can be attributed to a smaller facility space required in classes D and U.
Figure 4
Figure 4 shows the electrical energy ratios for the two manufacturing options. In the stainless-steel facility, the bulk of
the energy is needed to operate Class D, where the cell culture and solution preparation operations take place. When the stainless-steel
vessels are replaced with presterilized disposable components, the energy requirement is concentrated in the downstream purification
area (i.e., class B) instead of class D.
Lindsay Leveen is the product management team lead for lytics at Genentech. He also writes a blog about the environmental impact of energy, at www.greenenergyexplained.com.
Articles by Lindsay Leveen
Vice President of marketing and disposables implementation at Biopharm Services. She is also the European chair of ISPE's Community of Practice for Disposable Technologies.
Articles by Miriam Monge
