KBB - April 2009 - (Page 56)

Education Vent for Success Clear the air on bathroom ventilation and IAQ Homes today are being built with more attention to air leakage and insulation than ever before. The homes of tomorrow will continue this trend, saving even more energy and further increasing comfort for their occupants. The result of this effort to decrease energy consumption creates an opportunity to manage indoor air quality (IAQ) effectively through the careful selection of materials and the proper use of mechanical ventilation. The wide variety of ventilation products available on the market today makes it possible to control air quality in every area of every home. Whether the need is to exhaust moisture from bathrooms or cooking odors from kitchens, or to improve overall air quality throughout the entire dwelling, quiet, energy-efﬁcient solutions are readily available. However, without an appropriately designed, installed and maintained ventilation system, the beneﬁts of these better-built homes can become liabilities. out to one cubic foot per minute (cfm) per square foot of bathroom area (e.g., 70 cfm for a 7-ft. x 10-ft. bathroom), but a minimum of 50 cfm is required even for small bathrooms. Additionally, bathroom fans should be able to operate at 50 cfm intermittently or 20 cfm continuously. When used to meet the intermittent ventilation requirements, it is recommended that bathroom fans be HVI-Certified at no more than 3.0 sones. RATINGS AND GUIDELINES Ventilation products have differing capacities for moving air, making it important to ensure that the selected product has ample capacity for the application. HVI’s Certiﬁed airﬂow rating appears on the product or on the HVI label displayed on each unit, in the manufacturer’s literature describing the fan and in the HVI Certiﬁed Home Ventilating Products HVI recommends the following intermittent ventilation rates for bathrooms: HEALTH AND HOME Bathroom size During a bath or shower, the humidity level in a bathroom can be like that of a tropical rain Smaller than 100 sq. ft. forest—uncomfortable, hot and damaging—a Larger than 100 sq. ft. perfect breeding ground for mold, mildew and microorganisms that can impact a person’s health. In addition, excess moisture has tremendous potential for damaging the home. It cracks and peels paint, ruins gypsum wallboard, warps doors and rusts cabinets and ﬁxtures. Without control, it can even cause deterioration of joists and framing above the bathroom. As it condenses on windows, walls, ceilings and cabinets, it attracts dirt and makes more frequent cleaning and decorating necessary. It encourages mildew on tile grout and generally provides an environment for increased bacterial growth. Bathroom exhaust fans, when correctly installed and ducted to the outside, remove moisture and prevent these types of problems in bathrooms and spa areas, providing much better IAQ than windows. Not only will occupants be more comfortable after a bath, shower or spa, but the room will also be rid of odors, potentially hazardous aerosol vapors and other pollutants. In addition to fostering healthier air, this minimizes the potential for home damage, saving the homeowner the cost of making repairs to correct preventable problems. The Home Ventilating Institute (HVI) recommends ventilation rates based on eight air changes per hour. For most bathrooms, this works Calculation formula 1 cfm per sq. ft. of ﬂoor area Add the cfm requirement for each ﬁxture Ventilation rate required A minimum of 50 cfm Toilet: 50 cfm Shower: 50 cfm Bathtub: 50 cfm Jetted tub: 100 cfm Directory, a link to which is found on the HVI home page at www.hvi.org. In addition, the following guidelines should also be met: • An enclosed toilet compartment should have its own exhaust fan. • Fans approved for installation in wet areas should be located over the shower or tub whenever possible (requires a GFCI-protected circuit). • Bathroom doors need to have at least 3/4 in. of clearance to the ﬁnished ﬂoor to allow proper entry of makeup air. • For steam rooms, HVI recommends a separate fan located in the steam room that can be turned on after use to clear the heat and humidity. • The bathroom exhaust fan should have a control that will allow the fan to run at least 20 to 30 minutes after each shower to ensure that moisture levels are reduced. It is also possible to vent bathrooms with a central exhaust system using inline fans or heat or energy recovery ventilators (HRV/ERV). When a continuous ventilation system, such as an HRV or ERV, is installed, a 56 + K BB April 2009 / www.kbbonline.com / The Ofﬁcial Sponsor of K/BIS www.kbis.com Jully2004 http://www.hvi.org http://www.kbbonline.com http://www.kbis.com

Table of Contents for the Digital Edition of KBB - April 2009

KBB - April 2009
Contents
Online Contents
Online News
Editorial
Focus
Trends
Products
Options
Profile
Abroad
Design
On the Hill
Mixed Message
Green
Tech
Additions
Education
Editorial Index
Ad Index
Favorites

KBB - April 2009