Written by RAFFE KHAZADIAN, AIA, NCARB, LEED AP O+M, CDT | Principal/Director of Life Science, Ci Design, Inc.
Manufacturing companies, especially those within the medical industry, sterilize products and equipment before they are distributed for public use. Not only does the FDA require this, but it also has a list of recognized sterilization standards to which a facility must adhere.
Read on to learn more about the components of a sterilization facility and what to consider in the design.
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Sterilization is the process of eliminating all forms of microbial life on a product through physical or chemical methods. This can occur in-house in a dedicated area or in a separate sterilization facility. The most common sterilization method, employed by over 50% of medical device manufacturers, uses the chemical ethylene oxide (EO).
Because EO is a high-risk, highly flammable chemical that can cause negative symptoms in humans if exposed, it is essential that sterilization facilities are designed to ensure the safety of the building’s occupants, the facility itself, and the environment.
DESIGN REQUIREMENTS OF A STERILIZATION FACILITY
EO sterilization facilities have strict requirements and guidelines, many of which relate to fire protection and emissions control.
FIRE PROTECTION
Fire protection is of the utmost importance in a sterilization facility. The electrical systems must be intrinsically safe, which means they must be incapable of releasing enough energy to cause the ignition of atmospheric mixtures, and the devices used must be protected from sparks. Furthermore, deflagration venting must be installed to relieve pressure, if necessary. Finally, the EO liquid must be housed in a building separate from the one in which sterilization occurs.
EMISSIONS CONTROL
To limit the free spread of EO throughout the facility and into the atmosphere, an emissions control system must be installed. These systems are fundamental to the disposal of EO without causing excess harm to the environment.
COMPONENTS
Sterilization facilities, due to the complexity and number of steps in the sterilization process, often have a number of essential components.
PRECONDITIONING CHAMBER
The sterilization process begins when products—in their final packaging—are delivered to the preconditioning chamber. These are closed, insulated chambers that heat and humidify products to specific values to allow the EO to permeate and sterilize the products more efficiently.
STERILIZATION CHAMBER
Once preconditioned, the products are delivered to a sterilization chamber. These are large chambers that often hold 50-100 pallets of product. The chambers are injected with steam and the air is replaced with nitrogen before the EO permeates.
PUMP SYSTEMS
Next, liquid EO is transported from the supply cylinders in an external unit or building, heated, and then pumped as a gas into the sterilization chamber. The systems and infrastructure used in this process must also adhere to strict codes and design regulations.
AERATION ROOMS
Once EO has permeated and sterilized products, the product is moved to an out-parcel building where it can be appropriately aerated with nitrogen. This building often includes a scrubber unit, which is an air pollution control device, to remove residual EO from the air. Product is then transported to a secondary aeration room where it is placed, still under vacuum, to continue to off-gas in the facility.
After off-gassing is complete, the products are loaded back onto trailers and are ready to be shipped.
HOW STERILIZED PRODUCTS ARE HANDLED BY OTHER FACILITIES
When the product reaches its next destination, many organizations require EO sterilized goods to be stored in a separate room under negative pressure in case there is any additional off-gassing. Some facilities even add more air scrubbers in their warehouses to eliminate extra off-gas and ensure the safety of their employees.
DESIGNING THE PROCESS FOR THE PRODUCT
The EO sterilization process can put stress on the products and materials being sterilized, so it is imperative that the sterilization cycle is designed specifically for the product and its packaging. Process engineers and experienced designers should be employed to design appropriate solutions, which can include incorporating additional special equipment and sensors for more sensitive product.
THE WRAP-UP
Organizations that manufacture sterile products must adhere to very strict requirements, which can make the design process complex and the facility construction expensive. It is important to work with experienced architects, engineers, and construction management teams to ensure these sterilization facilities are designed to remain safe for their users and surrounding environments.