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2015 INTERNATIONAL RESIDENTIAL CODE <br />NOTE: Tables M1507.3.3(1) and M150713.3(2) are adopted <br />as published in the 2015 IRC, and are not duplicated here. <br />M1507.1 General. Local exhaust and whole -house mechanical <br />ventilation systems and equipment shall be designed in <br />accordance with this section. <br />M1507.2 Recirculation of air. Exhaust air from bathrooms <br />and toilet rooms shall not be recirculated within a residence or <br />to another dwelling unit and shall be exhausted directly to the <br />outdoors. Exhaust air from bathrooms and toilet rooms shall <br />not discharge into an attic, crawl space or other areas of the <br />building. <br />M1507.3 Whole -house mechanical ventilation system. <br />Whole -house mechanical ventilation systems shall be designed <br />in accordance with Sections M1507.3.1 through M1507.3.3. <br />M1507.3.1 System design. Each dwelling unit or guestroom <br />shall be equipped with a ventilation system complying with <br />Section M1507.3.4, MI507.3.5, M1507.3.6 or M1507.3.7. <br />Compliance is also permitted to be demonstrated through <br />compliance with the International Mechanical Code or <br />ASHRAE Standard 62.2. <br />M1507.3.2 Control and operation. <br />1. Location of controls. Controls for all ventilation <br />systems shall be readily accessible by the occupant. <br />2. Instructions. Operating instructions for whole -house <br />ventilation systems shall be provided to the occupant <br />by the installer of the system. <br />3. Local exhaust systems. Local exhaust systems shall <br />be controlled by manual switches, dehumidistats, <br />timers, or other approved means <br />4. Continuous whole -house ventilation systems. <br />Continuous whole -house ventilation systems shall <br />operate continuously and be equipped with an <br />override control. A "fan on" switch shall be permitted <br />as an override control. Controls shall be capable of <br />operating the ventilation system without energizing <br />other energy -consuming appliances. A clearly visible <br />label shall be affixed to the controls that reads <br />"Whole House Ventilation (see operating <br />instructions)." <br />5. Intermittent whole -house ventilation systems. <br />Intermittent whole -house ventilation systems shall <br />comply with the following: <br />5.1. They shall be capable of operating <br />intermittently and continuously. <br />5.2. They shall have controls capable of operating <br />the exhaust fans, forced -air system fans, or <br />supply fans without energizing other energy - <br />consuming appliances.5.3 <br />5.3. The system shall be designed so that it can <br />operate automatically based on the type of <br />control timer installed. <br />5.4. The intermittent mechanical ventilation system <br />shall operate at least one hour out of every <br />four. <br />5.5. The system shall have a manual control and <br />automatic control, such as a 24-hour clock <br />timer. <br />(Insert Facing Page 487) <br />5.6. <br />5.7. At the time of final inspection, the automatic <br />control shall be set to operate the whole -house <br />fan according to the schedule used to calculate <br />the whole -house fan sizing. <br />5.8. A label shall be affixed to the control that reads <br />"Whole House Ventilation (see operating <br />instructions)." <br />M1507.3.2.1 Operating instructions. Installers shall <br />provide the manufacturer's installation, operating <br />instructions, and a whole -house ventilation system <br />operation description. <br />M1507.3.3 Mechanical ventilation rate. The whole - <br />house mechanical ventilation system shall provide <br />outdoor air to each dwelling unit at a continuous rate of <br />not less than that determined in accordance with Table <br />M1507.3.3(1). <br />Exception: The whole -house mechanical ventilation <br />system is permitted to operate intermittently where the <br />system has controls that enable operation for not less <br />than 25 percent of each 4-hour segment and the <br />ventilation rate prescribed in Table MI507.3.3(1) is <br />multiplied by the factor determined in accordance with <br />Table MI507.3.3(2). <br />M1507.3.4 Whole -house ventilation using exhaust fans. <br />This section establishes minimum prescriptive requirements <br />for whole -house ventilation systems using exhaust fans. A <br />system which meets all the requirements of this section shall <br />be deemed to satisfy the requirements for a whole -house <br />ventilation system. <br />M1507.3.4.1 Whole -house ventilation fans. Exhaust <br />fans providing whole -house ventilation shall have a flow <br />rating at 0.25 inches water gauge as specified in Table <br />M1507.3.3(1). Manufacturers' fan flow ratings shall be <br />determined according to HVI 916 or AMCA 210. <br />M1507.3.4.2 Fan noise. Whole -house fans located 4 feet <br />or less from the interior grille shall have a cone rating of <br />1.0 or less measured at 0.1 inches water gauge. <br />Manufacturer's noise ratings shall be determined as per <br />HVI 915 (March 2009). Remotely mounted fans shall be <br />acoustically isolated from the structural elements of the <br />building and from attached duct work using insulated <br />flexible duct or other approved material. <br />M1507.3.4.3 Fan controls. The whole -house ventilation <br />fan shall meet the requirements of Section M1507.3.2 and <br />M1507.3.2.1. <br />M1507.3.4.4 Ventilation openings. Each habitable space <br />shall be provided with outdoor air inlets or operable <br />windows with an openable area not less than 4 square <br />inches of net free area of opening for each 10 cfm of <br />outdoor air required by Table M1507.3.3(1). Where <br />outdoor air supplies are separated from exhaust points by <br />doors, provisions shall be made to ensure air flow by <br />installation of distribution ducts, undercutting doors, <br />installation of grilles, transoms, or similar means. Doors <br />shall be undercut to a minimum of 1 /2 inch above the <br />surface of the finish floor covering. <br />r <br />Effective July 1, 2016 <br />i <br />