Issue link: http://iaqnet.uberflip.com/i/637209
Standard for Measuring Residential Dryer Exhaust Duct Performance The NADCA Standard • 2014 15 Actual Length: The total measured length of the dryer exhaust duct. Adhered Substance: A material that is not removable by direct contact with a brushing device using silicon carbide bristle. Cementitious: Any various building materials which may be mixed with a liquid such as water to form a cement-like substance. Debris: Non-adhered substances not intended to be present within the dryer exhaust duct system. NADCA Dryer Exhaust Duct Performance (DEDP) Test: The testing methodology developed by NADCA to measure dryer vent performance after servicing. Developed Length: The actual length of duct added to the equivalent length of all installed dryer exhaust duct fittings. The virtual lengths are derived from a standardized table on frictional loss within the IMC and IRC Code for hard turns of 90 and 45 degrees. Differential Pressure Gauge: An instrument that is used to show the relative pressure difference. For the purpose of this Standard the gauge shall have a range of 0.0 to 2.0 inches of water column (wc). Dryer: An appliance that removes moisture by forced draught, heating, or centrifuging. Dryer Exhaust Duct Connection: The point at which the transition duct connects to the dryer exhaust duct. Dryer Exhaust Duct: Exhaust ducts that have a smooth interior finish, are constructed of metal, and are 4" (102 mm) nominal in diameter. Dryer Exhaust Duct Testing Device: NADCA- designed device used to connect to a dryer exhaust duct to generate consistent pressure and velocity using a known constant. Equivalent length: The resistance of a flexible transition duct, elbow, bend, fitting, or other obstruction to flow, expressed in the number of feet of straight duct or pipe of the same diameter that would have the same resistance. Exhaust Penetrations: Point at which a dryer exhaust duct passes through a wall or ceiling membrane. Flexible Transition Ducts: Class 0 – Transition ducts and air connectors are those ducts having surface burning characteristics of zero. Class 1 –Transition ducts and air connectors are those having a flame- spread index of not over 25 without evidence of continued progressive combustion and a smoke-developed index of not over 50. Inspection: A gathering of information for use in making determinations and assessments. International Mechanical Code (IMC): The IMC is a model code that regulates the design and installation of mechanical systems, appliances, appliance venting, duct and ventilation systems, combustion air provisions, hydronic systems and solar systems. DEFINITIONS