The International Residential Code (IRC) is a model code published by the International Code Council. Although this model code is considered a benchmark in the building industry, it does not have the force of law until adopted by a state or municipal code agency. In 2012, the IRC incorporated the Residential Provisions of the International Energy Conservation Code into the sections on Energy Efficiency. The IRC model code requirements represent important standards for energy efficiency in building design and construction. Although not all parts of the energy efficiency code are applicable to bathroom design, it is necessary for a designer to have an overall understanding of an energy-efficient building as represented by the IRC. This understanding prepares you for applying relevant parts of the code to your particular design project.
The 2012 IRC divides the United States and Canada into eight climate zones. Many code requirements are then specific to each climate zone, which is designated by state, province, county, and
territory. The energy-efficiency section of the code emphasizes creating a building structure that has a thermal envelope and air barrier that minimizes heat loss in winter, heat gain in summer, and air leakage year-round. This is done with construction standards that are appropriate and cost effective to the climate.
Of interest to the bathroom designer are the following requirements for windows, doors, and walls:
• U-factors for windows, skylights, and exterior doors. U-factor is a measurement of heat conductivity or thermal transfer. The lower the U-factor, the more energy efficient the window or door.
• Solar heat gain coefficient (SHGC) for windows. SHGC and other window characteristics are detailed in chapter 2, "Infrastructure Considerations."
• R-value of insulation in floors, walls, and ceilings. R-value is a measure of the resistance to heat conductivity. The higher the R-value, the better the insulation.
The code provides detailed information about sealing the structure to limit air infiltration as well as where to locate insulation. In addition, there are requirements related to ventilation, which are further discussed in chapter 7, "Mechanical Planning." Of particular note is the requirement for whole house mechanical ventilation to provide adequate fresh air.
From the beginning of the design process, it is important to be aware of the influence of energy-efficiency codes on potential design and space solutions. Issues such as wall thickness and floor area; selection and placement of doors, windows, and lighting fixtures; placement of plumbing pipes and fixtures; and installation of venting systems are examples of design and construction decisions that can be influenced by requirements of the energy code.
A bathroom is a wet place. Water is used for many purposes, both utilitarian and luxurious. In the process of using a bathroom, people may swallow, inhale, and absorb water. For these reasons, the water used in a bathroom should be safe and healthy, as well as smell, taste, and look good. Clients need water that works well for all bathroom uses and does not contribute to maintenance problems. At the same time, water is a finite resource, and we have a responsibility to use it wisely and efficiently. The designer is an important influence in sustainable use of water in the bathroom.
Chapter 2, "Infrastructure Considerations," of this book discusses issues of an adequate water supply, water pressure, and the plumbing infrastructure necessary for a well-designed bathroom. This chapter first discusses issues of water quality—water that is safe, healthy, and functional for use in the bathroom. Next, efficient and sustainable use of water in the bathroom, especially in the choice of water-efficient fixtures, is presented.