ASME A112.4.1-2009 pdf download.Water Heater Relief Valve Drain Tubes.
1 GENERAL 1.1 Scope This Standard establishes performance requirements and test methods applicable to water heater relief valve drain (or runoff) tubes for use with relief valves having a steam rating of 105,000 Btu/hr or less. 1.2 Reference Standards The following reference standards shall be used to evaluate the product, and are cited herein. Unless indi- cated, the latest edition of these standards shall be appli- cable for certification to this Standard. ANSI Z21.22, Relief Valves for Hot Water Supply Systems Publisher: International Association of Plumbing and Mechanical Officials (IAPMO), 20001 Walnut Drive, South Walnut, CA 91789-2825 (www.iapmo.org) ASME B1.20.1, Pipe Threads, General Purpose (Inch) Publisher: The American Society of Mechanical Engineers (ASME), Three ParkAvenue, New York, NY 10016-5990; Order Dept: 22 Law Drive, P. O. Box 2900, Fairfield, NJ 07007-2900 (www.asme.org) 2 REQUIREMENTS 2.1 Size The drain tube shall have a minimum inside diameter of 3 ⁄ 4 in. and a minimum length of 48 in. 2.2 Material The material that is used in the composition of the drain tube shall be capable ofwithstanding the tempera- ture tests cited in section 3 without collapse or perma- nent distortion. Materials shall be corrosion resistant. 2.3 Joints Any joints within the tube shall be firmly affixed and shallwithstand thetemperature tests withoutseparation or leakage. Assembly of the drain tube to the relief valve shall be possible by hand-tightening only. Connecting threads shall comply with ASME B1.20.1 for 3 ⁄ 4 in. NPT pipe threads.
2.4 Installation Instructions Installation instructions, including post-installation relief valve testing procedures, shall be provided with the unit. A permanent tag or label relating to the relief valve test procedures shall be provided with the device. 2.5 Marking and Identification 2.5.1 The manufacturer’s name or trademark shall be permanently marked on the drain tube. 2.5.2 For products intended for other than OEM applications, the limitations of installation for the drain tube shall be permanently marked on the tube in let- tering not less than 0.125 in. in height. For example, “HAND-TIGHTEN ONLY,” “USE ONLY ON T & P VALVES WITH 105,000 Btu/hr OR LESS RATING,” or “NO PIPE SEALANTS.” 3 TEST METHODS AND PERFORMANCE REQUIREMENTS 3.1 Temperature Test 3.1.1 Test Equipment. A steam-generating source capable of producing 105,000 Btu/hr at 15 psig pressure and 250°F temperature shall be used to conduct this test. The steam source shall be fitted with instruments that measure pressure and temperature. The steam source shall be connected to a 3 ⁄ 4 -in. relief valve that complies with ANSI Z21.22. The relief valve shall be mounted horizontally and the drain tube shall be installed in a downward position. For drain tubes intended for instal- lationinreliefvalve locations atthe top ofa water heater, the test assembly shall be installed with the relief valve in a vertical position and the drain tube connected and tested accordingly. 3.1.2 Test Method. Prior to conducting this test, the inside diameter and length of the drain tube shall be measured and recorded. A thermocouple shall be attached to the outside surface of the drain tube within 3 in. ± 0.5 in. of the relief valve in order to measure the equilibrium temperature.