ASME B31.9:2016 pdf free download.Building Services Piping.
920.2.2 Test Loads on Spring Hangers. Load condilions for calculated operation of spring hangers should not take test loads into account. The hanger assembly, however, shall be capable of supporting the test load unless additional supports are provided during testing.
921 DESIGN OF PIPE-SUPPORTiNG ELEMENTS
921.1 General
Pipe-supporting elements shall be designed to carry the sum of all concurrently acting loads described in para, 920. Unless designed to anchor or restrain line movements by withstanding the resultant forces and moments, they shall permit free movement of the piping resulting from thermal expansion or other causes.
In addition, supports shall be so located and spaced as to protect the supported piping from excessive stress and distortion.
921.1.1 MaterIals and Stresses. Except as permitted herein, materials for pipe-supporting elements shall be listed in Mandatory Appendix I. Allowable stresses for pipe-supporting elements shall be one-fourth of the minimum tensile strength shown in Mandatory Appendix I. For carbon steel of unknown specification, the allowable stress shall not exceed 9,500 psi (65.5 MPa).
(a) Threaded Parts. The maximum safe loads shall be calculated on the root area of the threads of threaded parts.
(b) An increase in allowable stress is permitted up to 80% of specified minimum yield strength during hydrostatic testing, not to exceed 24,000 psi (165.5 MI’a) for carbon steel of unknown specification.
(c) Selection of Material. Hanger and support materials shall be compatible with the characteristics of the piping materials, so that neither shall adversely affect the other.
921.1.2 Hanger Mjustments. Hangers supporting piping NPS 2 (UN 65) and larger shall be designed to permit adjustment after erection while supporting the load. Threaded parts for adjustment shall be in accordance with ASME B1.1.
Tumbuckles and adjusting nuts shall have full thread engagement. Threaded adjustments shall be provided with suitable locking devices.
921.1.3 Support Spacing
(a) Piping Stresses. Stresses in the piping due to support spacing shall not exceed the basic allowable stress S when computed on the basis of a support span twice as great as the actual span.
(b) Limitations on Charts. The spans in Figs. 921.1.3-1and 921.1.3-2 are based on limitations in paras. 921.1.3(a)and (b) and are not applicable where there are concen-trated loads,i.e., valves, special fittings, etc. Spans anddeflections are based on the simple beam formulas lim-iting the combined pressure and bending stress to thebasic allowable stress for the material.
921.1.4 Springs. Springs used in spring hangersshall be designed and manufactured in accordance withMSS SP-58.
921.2 Fixtures
921.2.1 Anchors and Guides
(a) Requirements. Anchors, guides, pivots, and otherrestraints shall be designed to secure the piping at theirrespective locations against movement in specifiedplanes or directions,while permitting free movementelsewhere. They shall be structurally suitable to with-stand the thrusts,moments, and other imposed loads.
(b)Required Guides. Where bellows or slip-typeexpansion joints are used, anchors and guides shall beprovided to direct expansion movement along the axisof the joint.
ASME B31.9:2016 pdf free download
