ASME A112.6.9-2005 pdf download

ASME A112.6.9-2005 pdf download.Siphonic Roof Drains.
1 GENERAL 1.1 Scope This Standard establishes minimum requirements and provides guidelines for the proper design, installation, examination, and testing of siphonic roof drains. It includes definitions of terms and parameters involved in the proper design of siphonic drainage systems. This Standard applies to roof drains designed, manu- factured, and installed in piping systems that are intended to operate under depressurized siphonic con- ditions created by the connected piping system. Unless noted otherwise in this Standard, the require- ments and standards for roof drains specified in ASME A112.6.4 do not apply to siphonic roof drains. This Standard does not apply to conventional roof drains covered under ASME A112.6.4. It is not the intent of this Standard to specify that a drain of a given diameter must drain a minimum or maximum amount of water. It is the intent of this Stan- dard to provide standardized test procedures to ensure that drain products are evaluated equally. This Standard does not dictate minimum flow or depth performance criteria for siphonic roof drains. Instead, it specifies standard test procedures to be per- formed on siphonic roof drain products to document their actual performance and physical limits. These data are to be made available in manufacturer literature for use by designers for selecting the drain product and enteringperformance characteristics into designcalcula- tions. 1.2 Units of Measurement Values are stated in U.S. Customary units and in the International System of Units (SI). The U.S. Customary units shall be considered as the standard. 1.3 Reference The following document forms a part of this Standard to the extent specified herein. Unless otherwise indi- cated, the latest edition shall apply. ASME A112.6.4, Roof, Deck, and Balcony Drains Publisher: The American Society of Mechanical Engi- neers (ASME), Three Park Avenue, New York, NY 10016-5990; Order Department: 22 Law Drive, P.O. Box 2300, Fairfield, NJ 07007-2300 1 1.6 Definitions and Nomenclature 1.6.1 Definitions air baffle: a device that limits the flow of air into a drain, causing the connected drainage piping to run at full- bore flow at dimensional rainfall intensity with a limited water depth on the roof surface. depressurized: the condition or state ofbeing below atmo- spheric or ambient pressure. designer: the specifier of a siphonic roof drain product. drain outlet: the drain “neck” of a siphonic roof drain configured to connect to the tailpiece with a standard coupling device. full-bore flow: the flow of water in a pipe where theoreti- cally 100% of the cross-section of the pipe bore is filled. In practical terms, full-bore flow is regarded as achieved at water content greater than 95% by volume. singleresistancevalue, K i : a coefficientthatis characteristic ofa pipe fitting’s or drain’s contribution to energy losses. 1.6.2 Nomenclature cfs p cubic feet per second d i p pipe inner diameter, ft f p friction factor (dimensionless) g p gravitational constant, 32.2 ft/sec 2 gpm p gallons per minute h t p height, ft K i p single resistance value (dimensionless) k 0 p resistance coefficient (dimensionless) L p pipe length, ft L/s p liters (metric liquid) per second P p static pressure, lb f /ft 2 or ft H 2 0 Q p volumetric flow, cfs Re p Reynold’s Number (dimensionless) ? p fluid density, slug/ft 3 V p fluid velocity, ft/sec ? p fluid kinematic viscosity, ft 2 /sec w.c. p water column 2 ACCEPTABLE MATERIALS AND COMPONENTS 2.1 Siphonic Roof Drains The materials of construction, finishes, and hardware components used to manufacture siphonic roof drains shall comply with the requirements of ASME A112.6.4, para. 5.
3 TESTING 3.1 General 3.1.1 Manufacturers of siphonic roof drains may uti- lize existing conventional drain body designs with an air baffle adaptor to achieve siphonic capability when connected to a properly engineered siphonic drainage piping system. This adaptation, however, requires hydraulic analysis in order to ensure the baffle design is stable, will be capable of priming, and will minimize the depth of water on the roof as much as possible. 3.1.2 Siphonic roof drain products shall be verified experimentally and have documented results. 3.1.3 The design of any air baffle and drain shall follow three main principles: (a) It shall be able to prime the test standpipe quickly. Thus, the height of the baffle above the sump bowl should be minimized. This will help achieve a high Reynolds Number beneath the baffle and the necessary turbulence for proper air to water mixing during priming. (b) The baffle shall not introduce a limiting effect with respect to maximum flow. In other words, the drain shall be limited in maximum flow capacity by the fixed spigot drain diameter and not by the introduction of a baffle. (c) The first two goals must be balanced with the desire to have a minimum of water depth on the roof above the baffle, which means that the resistance of the baffle/drain/strainer combination should be mini- mized. 3.2 Design of Siphonic Drains 3.2.1 The design of any siphonic roof drain shall follow the basic principles described in para. 3.1.3. 3.2.2 The materials, spigot connections, compo- nents, and leaf guard designs of siphonic roof drains shall meet with the minimum requirements of ASME A112.6.4, with the exception of the air baffle design. 3.2.3 This Standard is not intended to restrict or prohibit the development or application of new and innovative siphonic roof drainage products provided that such products conform to the spigot connection requirements of ASME A112.6.4. 3.2.3.1 A spigot connection type shall not reduce or increase the flow path in a manner that will alter the drain’s tested single resistance value. 3.3 Testing of Siphonic Roof Drains 3.3.1 The following test procedures shall be applied to siphonic roof drain products. 3.3.2 These tests have three purposes (a) to determine the relationship between the flow rate entering the drain and the depth of water at the 2 approach to the drain (i.e., the flow rating curve for the product) (b) to determine the head loss coefficient (i.e., single resistance value) for the drain for use by the designer for designing the piping system in which the drain will be installed (c) to checkthe effectiveness ofthe drainatpreventing entry of air and for the speed of response to sudden changes in flow rate 3.3.3 The performance characteristics of a siphonic roof drain product are vital in the attainment of full- bore flow in the connected piping system. 3.3.4 The relationship between flow rate and upstream depth of rain water depends on where the drain is to be installed. For a given flow rate, the depth will be less on a flat roof than in a gutter. The narrower the gutter, the greater the upstream depth. Siphonic roof drains shall be tested for the most critical condition in which the drain is intended to be installed. 3.3.5 These test procedures do not include the per- formance and flow capacity of the connected siphonic piping system.