Prior to entering a cleanroom, employees need to get “gowned up” in special clothing designed to trap contaminants that are naturally generated by our bodies. Depending on the room classification or function, personnel gowning may be as limited as hairnets/beard covers and lab coats, or as extensive as being fully enveloped in multiple layered bunny suits with self-contained breathing apparatus.
The Gowning Room
Cleanroom personnel generally “boot up” in dedicated shoes or shoe covers, and in order to make sure they don’t get contaminants on the shoe covers before entering the cleanroom, they typically follow a transition protocol from the “dirty” to the “clean” side of the floor/room. This usually entails a gowning bench or chair placed along a line that has been taped or painted on the floor, or along the line between two different colored floor tiles. While sitting, the employee puts the first shoe cover on, puts that foot down on the “clean” side, then repeats the action for the second foot. Sometimes regular shoe covers tear while being put on, so the employee has to take them off, throw them away, and start the process over again.
A much easier, safer, and faster way of putting shoe covers on is to use a Shoe Inn automatic shoe cover dispenser. These dispensers are similarly placed along the line between the “dirty” and “clean” parts of the floor. In this setup, while standing on the “dirty” side, the employee puts the first shoe cover on, puts that foot down on the “clean” side, then repeats the action with the second foot and proceeds to the next step in the gowning process. Because the employee does not have to go grab precisely two shoe covers, walk to the bench, sit down, put the shoe covers on, and stand back up, not to mention not having to deal with improperly sized and torn shoe covers, the “booting up” process is much more efficient, which can help alleviate gowning room bottlenecks and significantly improve productivity.
While many companies use shoe covers to prevent contamination, many Shoe Inn customers also use sticky mats to maximize contamination prevention. The utilization of multi-layer adhesive mats for cleanrooms is almost universal. However, how the mats are used is unique to each cleanroom. Mats can vary in size, color, number, and placement based on the logistics and characteristics of each individual cleanroom.
Mats should be placed in an area where they will be on clean, hard flooring. They should be placed just before or just after the ingress/egress point for each cleanliness or control change. It is suggested that the placement sites are worked backward from the final clean area or cleanroom.
cleanroom – gowning area
cleanroom – staging area
gowning area – control area
control area – common hallway
common hallway – warehouse or receiving
common hallway – public area
Matting should be placed so that all those passing through that point must step on the mats. Matting should be placed with the longer dimension of the mat in the same direction as the traffic flow for maximum footfalls on each mat. The minimum number of footfalls should be two with each foot for each location.
The proper size mat for each area of placement depends on the width of the opening and the variance and direction of the traffic. Normally the width of the mat should be 2/3rds to 3/4ths of the width of the doorway. It does not normally need to cover the full width because ordinary traffic passes through the middle of the doorway and not along the edge. However, if the traffic enters at a sharp angle or from the side of the entryway, then the width of the mat needs to be wider than the doorway to allow for enough footfalls.
As stated above, the length of the mat should be long enough to provide at least two footfalls with each foot at each location. Usually this is a minimum of 45 inches.
The color of the mats, which has no effect on the function of the mat, can vary from standard blue, white, and grey to custom colors and printed messages. In general, white shows the most dirt and particulates, and is normally preferred to make sure the layers are changed at frequent enough intervals. However, grey and blue work just as well when a maintenance schedule is set.
How often the layers should be removed depends on a number of factors:
How dirty the area the personnel are coming from is.
The number of people or pairs of feet per shift or per hour.
The difference in cleanliness between the areas.
The size of the mats and how many mats or locations are in the series.
In general, areas farther away from the cleanroom will be dirtier. Changing the layers at this point of use every half hour would be a benchmark with which to start. The final entry area into the cleanroom is probably from a clean area to a very clean area and each layer may last 4 to 8 hours.
However, this is just a rough guideline and each point of use will vary greatly. A few days of use and observation will help to determine the optimal mat layer change interval.
Before placing a new mat down or replacing an existing mat, thoroughly clean the surface to remove contamination that may act as a barrier and keep the mat from properly adhering to the floor. Make sure to remove any adhesive residue if you are replacing an existing mat. It is recommended to use a pre-saturated wiper that contains a percentage of isopropyl alcohol. Make sure the surface is completely dry before application.
To apply the mat, remove half of the release liner in the long direction of the mat, which will help with the alignment of the mat.
Once you have the mat properly aligned in the location you want, start smoothing out the half of the mat with the adhesive exposed. Start at one end and work toward the middle making sure you do not trap air under the mat as you go, then remove the rest of the release liner and smooth the rest of the mat out in the same direction in which you removed the release liner.
Matting should be stored flat and for several hours in similar climate conditions as the point of use. For ideal results, the mats should be used in a controlled environment setting but may be placed in any area that has a temperature of 54-95 oF (12-35 oC).
Long-term storage of mats should always be on a flat and hard surface. Storage on the original shipping pallet is recommended. Normal warehouse conditions are usually acceptable but extreme temperatures (less than 32 or greater than 105 oF / 0 or 40 oC) should be avoided.
Storage of mats longer than one year from the date of purchase is not recommended. However, under normal storage conditions, matting should not have any variation in performance for a period of up to three years.
The utilization of multi-layer sticky mats for cleanrooms is almost universal. In fact, many customers who use the Shoe Inn automatic shoe cover dispensing system also use these adhesive mats to further help prevent contamination within controlled environments. Depending on various factors such as how dirty the area the personnel are coming from is and the level of cleanliness desired or mandated, this combined approach may be advisable or even required.
An automatic shoe cover dispenser, who needs that? When it comes to putting on shoe covers, you don’t think much about it — you just do what you’ve always done, sitting on a bench or balancing on one leg while trying to put a shoe cover on the other foot (what we call the “bootie hop”). Sounds simple, but for many people it is not. If you find it difficult to bend over and tie your shoes or to balance on one leg, then you know how challenging it can be to put shoe covers on. Quite frankly, most people who have to wear shoe covers despise putting them on. Also consider workplace injuries happening during the process of putting them on — they do happen. In fact, the “bootie hop” is a worker’s comp claim waiting to happen. Last but not least, what about the bottleneck that is created when you have a lot of people who need to put them on at the same time? Shoe Inn can help alleviate all of these issues. Shoe Inn automatic shoe cover dispensers are ideal for use in a variety of environments such as manufacturing and food processing plants, laboratories and clean rooms, medical and healthcare facilities, and anywhere else people need to put shoe covers on faster, easier, safer and cleaner. There is no doubt that you will benefit from the ease of use, time savings, and added safety from using Shoe Inn automatic shoe cover dispensers.
Have you ever considered what is on the bottom of your shoes? Besides things you can see, such as grease, oil, gum, mud, leaves, feces, etc., there are the countless things you cannot see, like germs, bacteria, mold, and viruses. All of these things walk with us everywhere we go, from the house to the car to the parking lot to the building to the lab or production area to the bathroom to the dining area and back again. How many other places do we go, like gas stations and public parks, picking up things on our shoes all along the way and transporting them where they are unwelcome?
As a result, many industries and settings require the use of shoe covers to maintain sanitary or sterile conditions, prevent contamination, limit the spread of infections, comply with health codes, etc. A review of the literature turned up several key findings such as the following:
“In this study, the authors subjected six occupied rodent holding rooms in their animal research facility to three conditions: use of disinfectant mats; use of shoe covers; and no disinfectant mats or shoe covers. The authors took bacterial culture samples from the rooms under each condition. There was no significant difference in the mean number of colony forming units (CFUs) cultured when the disinfectant mats or shoe covers were used. However, the mean number of CFUs obtained was significantly lower when either disinfectant mats or shoe covers were used than when neither was used. These results suggest that using disinfectant mats or disposable shoe covers may reduce the bacterial load on rodent holding room floors.”
“We recommend that gloves and footwear worn by employees who handle RF-RTE foods or who work in areas where RF-RTE are processed or exposed be made of impermeable material, in good repair, easily cleanable or disposable (emphasis added), and used only in RF-RTE areas.”
“Health care workers who handle hazardous drugs are at risk of skin rashes, cancer and reproductive disorders. NIOSH recommends that employers provide appropriate personal protective equipment (PPE) to protect workers who handle hazardous drugs in the workplace…Use hair and shoe covers constructed of coated materials to reduce the possibility of particulate or microbial contamination in clean rooms and other sensitive areas.”
Based on the above, it is clear that using disposable shoe covers is a credible and recommended method in a variety of situations and controlled environments.
 Allen KP, Csida T, Leming J, Murray K, Thulin J. Efficacy of Footwear Disinfection and Shoe Cover Use in an Animal Research Facility, U.S. National Library of Medicine, http://www.ncbi.nlm.nih.gov/pubmed/20305633
 US Food and Drug Administration, Guidance for Industry: Control of Listeria monocytogenes in Refrigerated or Frozen Ready-To-Eat Foods, Section XI, Paragraph IV