Proper architectural and engineering design is an art and a science. A professional designer should consider many aspects when specifying how a lavatory should be built. Functionality, esthetics, availability, and feasibility have all been proposed as points of emphasis in lavatory design. Infectious disease design considerations should also be prioritized in order to reduce society’s infectious disease burden. This article will: 1) Identify potentially dangerous pathogens transferred via fecal material; 2) Identify seven frequently contacted “high risk” lavatory surfaces where pathogens may collect; 3) Describe a rating system for evaluating the disease-preventing merits of a public lavatory; and 4) Propose specific lavatory design measures to reduce infectious disease spread.

The bathroom is a vital part of every public building. Unfortunately, public lavatories provide a dangerous medium for the spread of disease.¹ The authors believe that a “lavatory sanitation scale” will help draw attention to the critical need for thoughtfully designed bathrooms, and assist architects and engineers in “designing in” features which minimize the potential of societal infectious disease dissemination through public lavatory use. It is our objective to emphasize the risks of pathogen exposure, and encourage a process, which limits these exposures in the public setting. The ramifications these efforts have the potential to decrease human suffering, lessen the societal cost of healthcare, and limit the loss of human life.

Diseases spread by indirect fecal contact are common, costly, and deadly.² Worm, parasitic, bacterial, and viral pathogens may exist in fecal material and spread to others via direct or indirect contact. The effects of these diseases are staggering. When spread by the fecal-to-hand-to-oral route, these infectious processes may cause the common cold, high-grade fevers, severe gastroenteritis, liver failure, crippling paralysis, and even death.

The CDC (Centers for Disease Control) reports that rotavirus alone costs the United States one billion dollars a year, while causing 410,000 physician visits, 200,000 emergency room visits, 55,000- 70,000 hospitalizations and 20-60 deaths.³ On a global scale, this stool-spread virus kills 440,000 people a year.⁴ It is possible, that some of these deaths could have been prevented by hand washing and/or preventative lavatory design.⁵

Norovirus also causes a significant impact on societal health. Every year, 23 million cases of gastroenteritis are caused by this single-stranded RNA viral infection.⁶ This viral infection can be spread by the fecal-to-oral route, and is extremely contagious, requiring only 10 viral particles for disease transmission.⁶

From an infectious disease standpoint, the purpose of a bathroom should allow an individual to defecate or urinate, sterilize their hands, and exit without re-contaminating their hands on a surface previously contaminated. Lavatory design may benefit by including some of the aseptic features currently used in surgical suites. Pre-operative protocols mandate that a surgeon thoroughly wash their hands and enter an operating suite without touching any objects manually. Doors must be opened with the foot, back side, or by an automated process and water from a sink must be turned off in a fashion that preserves hand sterility. In order for a surgeon to dry their hands, they must use a sterile towel that has not been previously contaminated. Also, any direct hand or glove contact with a non-sterile surface is explicitly avoided. If at any time a physician’s sterile hand or glove touches a surface outside of the sterile field, they must reglove and/or rewash their hands before continuing.

Obviously, such meticulous proceedings cannot (and need not) be implemented at every public restroom; however, strategies for reducing potentially harmful dermal-to-surface-to-dermal contagions can be learned by studying these protocols. Methods designed to limit hand contamination can be implemented through innovative techniques and technology use. Much as a surgeon should be able to approach an anesthetized patient with sterile, gloved hands; an individual should be able to effortlessly escape a public restroom without having to needlessly touch contaminated surfaces.

In order to effectively design lavatories to minimize the chance of contagion spread, one must identify the frequently contacted surfaces where pathogens may predominate. We have identified seven critical points where a lavatory user may unnecessarily risk hand contamination. Of these seven points, faucet handles, soap dispensers, and paper-towel dispensers have been previously shown to have above normal staphylococcal counts.⁷ It is probable that our other identified points also contain increased bacteria and pathogen counts. Details regarding the seven avoidable surfaces of potential lavatory hand contamination are outlined below:

1. After toilet use, most conscientious users flush the toilet. If done manually, a user has contaminated their hand, as prior users of the same toilet have likely also flushed the toilet using a non-washed hand.
2. Once an individual leaves a stall, assuming that there is a latched door, they must open the latch. In doing so, users not only contaminate the latch and the doo,r but also potentially pick up contagions from prior users who touched these same surfaces. In some ways, these two points of contact may be considered less relevant, given that a user’s hands are already “non-sterile” and have yet to be washed. However, given that some users leave the bathroom without washing their hands at all, sanitary conditions at these two points may help to reduce the spread of disease.
3. After leaving a stall, a hand washer will turn on a sink’s faucet. Currently there are many varieties of bathroom faucets. Most of these require a hand to rotate a lever to begin water flow. Some of the more technologically sophisticated faucets use a foot pedal or sensor activation to begin water flow. In faucets, which do not use these technologies, contamination may transfer between a user’s hand and the faucet.
4. Contamination may occur when obtaining soap from a dispenser; particularly those that require direct hand contact.
5. In cases where the flow of sink water is not activated by a foot pedal, non-contact sensor, or time-release flow mechanism, an individual may stop the flow of water by reversing the position of a faucet lever or knob. When turning off a faucet manually, the benefit of the prior hand washing may be negated, as individuals can recontaminate their hands on a faucet previously touched by themselves and others.
6. An individual may contaminate their hands in the hand drying process. Like faucets, drying mechanisms are varied. Some hot air blowers require activation by pushing a button where as some paper dispensers require the turning of a knob or crank for paper acquisition. The most sanitary of these devices are automatic, or do not require the users to touch anything but a non-used paper towel. If any contact to commonly touched surfaces is necessitated in the hand drying process, then contagions may be spread.
7. Lastly, the exit of the bathroom provides the seventh point of possible infectious disease spread. It is here that an individual must place their hand on a handle or bar in order to leave the lavatory. It is here that patrons who wash their hands must touch the same surface, which is touched by people who choose not to wash their hands. Our country’s exact handwashing rate is unknown, but has been shown to be as low as 46 percent in select populations.⁸ This potentially leaves a high percentage of our population contaminating the exit doors of public bathrooms in cases where automatic or “doorless” serpentine exits are not used. Even in the scenario where every bathroom user meticulously washes their hands, a contaminated inward-opening bathroom door could potentially contaminate all users as they open the door. In rare occasions, bathroom users have been noted to use hand towels to open bathroom doors. This is hardly the ideal solution for public use, as it contributes to paper waste and the need for additional bathroom maintenance.

1. Toilet seat covers should be available and accessible. Toilet flushing mechanisms should be initiated though either a foot pedal, or automated device such as one that uses non-contact sensor activation.
2. If a lock is present on a stall door, it should be possible for the user to both unlock the stall door, and open it without use of either hand. This device could be easily implemented with a locking apparatus activated via a foot movement.
3. Ideally, water faucets should not require direct contact by the hand to start water flow. Faucets activated by foot pedals, or non-contact sensors can be utilized to minimize faucet contact.
4. A soap dispenser should dispense soap into the hand of the user without requiring the user to make contact with the soap dispenser. Current dispensers that do not require hand contact include those that use foot pedals or sensor activation.
5. Direct contact with a hand should not be required to stop faucet water flow. A foot pedal or a sensor activated device can be used for this purpose. Even though a time release faucet automatically stops water flow after a period of time, this is not the ideal faucet as the initial activation has the potential to contribute to hand contamination.
6. Hand drying apparatuses should not require a user to touch any surface other than that of a “sterile” hand towel. Paper towel dispensers should not require the turning of a crank or lever, and hot air blowers should be sensor activated. In addition, a bathroom user should not be required to touch a surface (trashcan lid) in order to dispose of a paper towel.
7. One should be able to leave a bathroom without using one’s hand. Possible solutions include a “doorless restroom” with a serpentine entrance, a mechanical door triggered by a foot pedal or sensor, or a latchless outward opening door.

Obviously, the perfectly designed lavatory cannot force individuals to wash their hands; however, it can provide an environment where one can use the restroom, wash their hands, and leave with limited hand contamination. It is possible that a well-designed bathroom will also encourage those who don’t regularly wash their hands to do so. We concede that several of our techniques for minimizing infectious spread require sparing the use of the hand in favor of the foot. We knowingly accept this exchange given that populations are much more at risk of fecal-to-oral infectious diseases when hand contamination occurs. Also, we must emphasize that designers must continue to give proper consideration to the handicapped population as they deserve the same infectious precautions as the general population. It is our hope that ultimately our proposed evaluation instrument will inspire future environmental designers to incorporate infectious disease considerations into their overall design process. Additional scientific and clinical research is required to definitively prove the degree of effectiveness these measures will have on society’s burden of disease.

References

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