Designing smart restrooms

Plumbing engineers should know the code when designing ADA-compliant and green restrooms.


Today’s building design focuses not only on design, constructability, beauty, and functionality, but also on making certain that the buildings are in compliance with model codes and standards. One aspect of design is the provision of environmentally conscious and Americans with Disabilities Act (ADA) compliant restrooms.

This article will review how the ADA standards were developed and how plumbing engineers will be able to assist architects in their designs. Then, the article compares the current and future standards with regard to the selection and layout of plumbing fixtures. The last part will focus on key considerations when trying to achieve green restrooms.

ADA and public restrooms

The U.S. Congress on Jan. 23, 1990, established a clear and comprehensive prohibition of discrimination on the basis of disability, known as the American with Disabilities Act of 1990.  ADA prohibits discrimination in employment, telecommunications, transportation, access to facilities, and programs provided by state and local government entities, and access to the goods and services provided by places of public accommodation. All “new construction,” which includes construction, modification, or alterations, must be fully compliant with the American with Disabilities Act Accessibility Guidelines (ADAAG), found in the Code of Federal Regulations at 28 CFR Part 36, Appendix A. Architects, engineers, and contractors who design and construct facilities are responsible for making them ADA-compliant, that is, accessible to and usable by people with disabilities.

The Architectural Barriers Act (ABA) was passed in 1968 to require all buildings with federal funding to comply with standards for physical accessibility. In 1991, the Dept. of Justice (DOJ) Code of Federal Regulations: Title III (28 CFR Part 36, revised July 1, 1994) was developed and now maintains all the ADA standards for places of public accommodation and commercial facilities (private sector), and state and local government facilities.

Published in 1961, American National Standards Institute (ANSI) A117.1 was based on research conducted by the University of Illinois under a grant from the Easter Seal Research Foundation. It was the first recognized national standard for accessibility whose main focus was wheelchair access. Further development by agencies and organizations like Council of American Building Officials (CABO) and International Code Council (ICC) changed design to an approach based on systematic research, adaptability concepts, and emphasis on accommodating a broader range of disabilities. Though a voluntary standard when it was first published, ANSI A117.1 has been adopted as an enforceable code by many state and local agencies that regulate the design and construction of built facilities. The standard is also referenced in the model building codes and now has become the consensus standard for the building industry, defining the minimum requirements for an accessible environment. Both the ADA standards and the ABA Standards have adopted the ANSI A117.1 section on Plumbing Elements and Facilities.

The DOJ’s 1991 ADA standards are in use currently, but after March 12, 2012, DOJ’s 2010 ADA standards will be mandatory.

Comparison of the current and future ADA codes and ANSI A117.1 is shown in Table 1. While it may seem that a number of items listed in this table fall within the architect’s responsibilities, it is important for plumbing engineers to ensure ADA-compliant placement of fixtures lest significant expense in rework be required.

For instance, grab bar and flush valve coordination: The standard indicates that the maximum height for the installation of the rear grab bar is 33 to 36 in. and the maximum height for the installation of the flush valve is also 36 in. If the hand bar were installed at 33 in., then it could conflict with the flush valve. Additionally, the standard requires that there should at least 1.5 in. space between the grab bar and any projecting object below, so coordination is essential. Another typical example is the P-trap and knee clearance coordination below lavatories, where counter depths and sink selections should be sufficient to maintain the required clearances at knee height. P-trap and valves should also be insulated.

Green codes and standards

Green building codes and standards, covering criteria for water use efficiency, energy efficiency, and so on, have been developed by the International Code Council (ICC) and ASHRAE. The International Green Construction Code (IGCC), National Green Building Standards (NGBS), and ASHRAE Standard 189.1 are available for adoption by state or local agencies.

The plumbing industry is responding to the codes and to today’s growing trend toward sustainable solutions by designing facilities that use less potable water. Manufacturers are also faced with advancing their technologies to respond to these trends. With new technologies come new considerations related to installation procedures and maintenance routines.

Waterless urinal considerations:

  • These fixtures use no water and do not need to be flushed after each use. They have a special liquid seal in the trap that keeps gases from escaping while urine passes through.
  • The lack of water use is a benefit when performing U.S. Green Building Council (USGBC) LEED calculations for water efficiency points.
  • Concerns:

    • Housekeeping staff must be trained to understand the manufacturer’s requirements for trap seal maintenance; otherwise, there will be a problem with odors escaping from the pipe.
    • Because the fixtures are waterless, urine creates a film around the pipe that solidifies and in the long run can cause the pipe to clog.- Some jurisdictions require installation of a water connection for future connections in the event that the owner finds the waterless urinal insufficient to his needs.

Low-flow urinal considerations:

  • The newest technology uses only 0.128 gal/flush (gpf).
  • The reduced water usage is a benefit when performing USGBC LEED calculations for water efficiency points.
  • This is the one of best technologies developed in response to the water efficiency trend that retains user familiarity while still achieving significant water reduction.

Water closet considerations:

  • The design team must decide whether to use a manual flush valve or electronic sensor flush. Electronic sensor flushing is often used in public assembly occupancies.
  • Use of the manual dual flush approach also reduces the amount of water and waste by giving the user the ability to apply judgment in flushing for waste removal.
  • The new 2010 ADA mandate requires 1.28 gpf. The best available model for dual flush has 1.28 gpf/1.1 gpf.
  • Signs are typically installed at the fixture to educate users about the system.
  • Concerns:

    • Very few users take the low flow flush option.
    • Oftentimes, it takes two flushes to evacuate the toilet, which leads to an increased usage as compared to baseline, so educational signs are quite important until this technology is more widely accepted.

Lavatory considerations: 

  • The design team must decide whether to use hand-operated, metering, or electronic sensor type for self-closing faucets. Electronic sensor faucets can either be hard-wired, battery-powered, or solar-powered with battery backup power source. Hand-operated faucets use 0.50 gpm flow restrictors.
  • Self-closing or metering faucets with lower than 0.50 gpm flow are now available in the market. The typical length of flow time is 10 seconds.
  • Concerns:

    • Some users do not use the full 10 seconds worth of water produced by self-closing faucets, thus water is wasted.
    • For metering faucets, there occasionally is difficulty in pushing the lever and most of the time users need two or three pushes to wash their hands.

The benefits of these new water-saving technologies are noted in Table 2. Let’s take an office building, for example, with 200 employees, divided into 100 males and 100 females. For purposes of this illustration, each female employee will use the water closet and lavatory twice a day, and each male employee will use the water closet and urinal once a day and the lavatory twice a day. It is also assumed that there are 250 days of operation per year and that a water-free urinal will be used as the high-efficiency urinal.

As shown in Table 2, substantial savings in water usage can be achieved by using low-flow fixtures. Additionally, plumbing engineers should consider whether further potable water reductions are possible through the use of treated grey water for water closet flushing, as is allowed in some jurisdictions.

The construction industry can expect to see future changes to the ADA standards and green codes. Universal design and water and energy conservation are at the center of a movement to embed our shared values into our design practices, and new technologies will arise to help us achieve these goals.

Enriquez is an associate plumbing and fire protection engineer with Arup. She has more than 30 years of plumbing and fire protection experience on a wide range of projects that include high- and low-rise buildings, mixed-used developments, hotels, schools, universities, health care facilities, theme parks, recreation centers, and museums.

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