It is safe to say that cleanability is one of the most important aspects of cleanroom design. Being able to efficiently sanitize your space cuts down on the risks of spore growth and decreases downtime. By surface area alone, the floor tends to be the largest part of the room that needs regular cleaning. This blog will cover a few different options available for how flooring can be installed and how it affects cleanability.
Below is the section of USP <797> that addresses the installation of flooring (as of 01/14/2021):
USP General Chapter <797> – Section 4.3 - Creating Areas to Achieve Easily Cleanable Conditions
“Floors must include coving to the sidewall, or the juncture between the floor and the wall must be caulked. Classified areas should minimize dust-collecting overhangs such as utility pipes and ledges such as windowsills. If overhangs or ledges are present, they must be easily cleanable.”
In this example, a wallcovering is used. The wallcovering typically begins 4-6 inches from the floor, extending to the ceiling. Seamless flooring is then rolled up the wall to butt up against the bottom of the wallcovering. The seam is then caulked to prevent moisture from seeping behind the wallcovering or flooring during cleaning.
By eliminating ledges and sharp corners that collect dust and other contaminants, this method provides the best overall cleanability. The downside to this method is that it is often the most expensive due to the cost of wallcoverings and their installation.
This method is often used on walls without wall coverings, such as epoxy-painted walls or aluminum and glass walls. Similar to Option A, the rolled flooring is retained. However, since there is no wallcovering a cove cap is required. The cap needs to be caulked to the wall at the top and the bottom where it meets the flooring. Caulking these gaps will prevent moisture from getting behind or inside the cap and avoid spore growth.
This method retains the cleanability of the rolled flooring and is less expensive than using wall coverings. The drawback to this method is that the cove cap creates a small ledge that will collect dust. This can be minimized by using a sloping cap, but it will still need to be cleaned regularly.
This method allows the flooring to be terminated at the base of the wall, with caulk sealing the seam.
Losing some of the cleanability provided by the rolled flooring, this method creates sharp corners where the wall meets the floor, especially at the inside corners of the room. Special care or equipment may be required to assure this space is properly cleaned. Conversely, there is no need to worry about cleaning a cove cap. In addition, the absence of rolled flooring simplifies the installation process reducing install time and required coordination.
All viable options, each method has a place in the cleanroom. When selecting a flooring method, other cleanroom choices and preferences should be considered; the types of wall, wall protection, and doors to be used. Costs and schedule will also need to be accounted for.