1、 MSS SP-127-2014a Bracing for Piping Systems: Seismic Wind Dynamic Design, Selection, and Application Standard Practice Developed and Approved by the Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. 127 Park Street, NE Vienna, Virginia 22180-4602 Phone: (703) 281-6613 F
2、ax: (703) 281-6671 E-mail: standardsmss-hq.org www.mss-hq.org Note: This 2014a Edition Replaces the Original 2014 Edition. MSS STANDARD PRACTICE SP-127i This MSS Standard Practice was developed under the consensus of the MSS Technical Committee 403 and the MSS Coordinating Committee. The content of
3、this Standard Practice is the resulting efforts of competent and experienced volunteers to provide an effective, clear, and non-exclusive standard that will benefit the industry as a whole. This MSS Standard Practice describes minimal requirements and is intended as a basis for common practice by th
4、e manufacturer, the user, and the general public. The existence of an MSS Standard Practice does not in itself preclude the manufacture, sale, or use of products not conforming to the Standard Practice. Mandatory conformance to this Standard Practice is established only by reference in other documen
5、ts such as a code, specification, sales contract, or public law, as applicable. MSS has no power, nor does it undertake, to enforce or certify compliance with this document. Any certification or other statement of compliance with the requirements of this Standard Practice shall not be attributable t
6、o MSS and is solely the responsibility of the certifier or maker of the statement. “Unless indicated otherwise within this MSS Standard Practice, other standards documents referenced to herein are identified by the date of issue that was applicable to this Standard Practice at the date of approval o
7、f this MSS Standard Practice (see Annex E). This Standard Practice shall remain silent on the validity of those other standards of prior or subsequent dates of issue even though applicable provisions may not have changed.” By publication of this Standard Practice, no position is taken with respect t
8、o the validity of any potential claim(s) or of any patent rights in connection therewith. MSS shall not be held responsible for identifying any patent rights. Users are expressly advised that determination of patent rights and the risk of infringement of such rights are entirely their responsibility
9、. In this Standard Practice, all text, notes, annexes, tables, figures, and references are construed to be essential to the understanding of the message of the standard, and are considered normative unless indicated as “supplemental”. All appendices, if included, that appear in this document are con
10、strued as “supplemental”. Note that supplemental information does not include mandatory requirements. U.S. customary units in this Standard Practice are the standard; the (SI) metric units are for reference only. This Standard Practice has been substantially revised from the previous 2001 edition. I
11、t is suggested that if the user is interested in knowing what changes have been made, that direct page by page comparison should be made of this document and that of the previous edition. Non-toleranced dimensions in this Standard Practice are nominal unless otherwise specified. Excerpts of this Sta
12、ndard Practice may be quoted with permission. Credit lines should read Extracted from MSS SP-127-2014a with permission of the publisher, Manufacturers Standardization Society of the Valve and Fittings Industry. Reproduction and/or electronic transmission or dissemination is prohibited under copyrigh
13、t convention unless written permission is granted by the Manufacturers Standardization Society of the Valve and Fittings Industry Inc. All rights reserved. Originally Approved: February 2001 Originally Published: May 2001 Current Edition Approved: July 2013 Current Edition Published: February 2014 M
14、SS is a registered trademark of Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. Copyright 2014 by Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. Printed in U.S.A. MSS STANDARD PRACTICE SP-127ii FOREWORD This Standard Practice was develop
15、ed by representatives from pipe hanger manufacturers that are MSS member companies in good standing. It is constructed based on analysis, the current practice at the time, and on the collective feedback and experience of the industry. This Standard Practice is intended for use with non-critical, sta
16、ndard commercial and industrial systems. There is a companion Standard Practice, ANSI/MSS SP-58, which relates to the materials, design, manufacture, selection, application, and installation of pipe hangers and supports. MSS STANDARD PRACTICE SP-127iii TABLE OF CONTENTS SECTION PAGE 1 SCOPE . 1 2 OB
17、JECTIVE 1 3 APPLICATION . 1 4 GENERAL REQUIREMENTS . 2 5 SELECTION PROCEDURE SINGLE PIPES . 4 6 SELECTION PROCEDURE TRAPEZE HANGERS . 4 7 PIPE BRACING DRAWINGS . 5 8 INSTALLATION 6 9 INSPECTION 6 10 SPECIAL BRACE TYPES . 6 TABLE 1 Maximum Span for Lateral Braces and Seismic Design Force . 7 1M Maxim
18、um Span for Lateral Braces and Seismic Design Force (SI) Metric Units . 8 2 Maximum Span for Lateral Braces and Wind Design Force . 9 2M Maximum Span for Lateral Braces and Wind Design Force (SI) Metric Units . 10 3 Fasteners: Load Data for Bolts 11 3M Fasteners: Load Data for (SI) Metric Bolts . 11
19、 3.1 Fasteners: Load Data for Expansion Bolts in Concrete . 12 3.2 Fasteners: Load Data for Embedded Bolts Cast in Concrete 12 3.3 Fasteners: Load Data for Lag Bolts or Lag Screws in Wood 13 4 Minimum Design Load Ratings for Brace Assemblies . 13 FIGURE 1 Cable (Wire Rope) Brace Requirements 14 2 Ty
20、pical Brace Members and Allowable Loads 15 2M Typical Brace Members and Allowable Loads (SI) Metric Units . 16 3 Typical Brace and Pipe Hanger Attachments . 17 4 Typical Structural Attachments 18 5 Typical Rod Stiffener Components 19 6 Pipe Supports that Also Act as Braces . 20 ANNEX A Calculating L
21、oads on Rods and Braces for Braced Hangers 21 B Example of Brace Assembly Drawing 26 C Graphical Solution Maximum Span for Lateral Braces and Wind Design Force 27 CM Graphical Solution Maximum Span for Lateral Braces and Wind Design Force (SI) Metric 28 D Examples of Determining Lateral Brace Requir
22、ements for Seismic and Wind Loads . 29 E Referenced Standards and Applicable Dates 32 MSS STANDARD PRACTICE SP-127iv This Page Intentionally Left Blank Manufacturers Standardization Society of the Valve and Fittings Industry MSS STANDARD PRACTICE SP-1271 1. SCOPE 1.1 This Standard Practice establish
23、es the material, design, fabrication, and inspection criteria to be used in the manufacture, selection, and application of standard types of bracing assemblies. 1.2 This Standard Practice presents recommended guidelines for providing stability in piping systems for protection against seismic, wind,
24、and other dynamic forces. 1.3 This Standard Practice is intended for use on piping systems where formal engineered bracing design may not have been performed. Note that local and/or national building codes or regulations may supersede or augment these requirements. 1.4 This Standard Practice applies
25、 to rigidly connected metallic pipe only (welded, flanged, mechanical-jointed, etc.). For other types of pipe and pipe connections, contact the applicable pipe manufacturer for information. 2. OBJECTIVE 2.1 To serve as a bracing standard, that includes selection and application, for seismic, wind, a
26、nd other dynamic forces. This Standard Practice can be referenced in whole or in part if so designated. 2.2 To serve as a guide to proven industry practice during engineering design and writing of job specifications covering seismic, wind, and other dynamic bracing of piping systems. 2.3 To provide
27、the erector with information on types of seismic, wind, and other dynamic bracing to be used for specific applications and installations, where such information is not already provided. 2.4 To serve as a companion document to ANSI/MSS SP-58. ANSI/MSS SP-58 also provides definitions used in this Stan
28、dard Practice. 3. APPLICATION 3.1 All piping systems subjected to seismic loading shall be braced for seismic forces in accordance with the requirements of this Standard Practice, unless otherwise defined in local and/or national building codes or regulations. 3.1.1 The charts below identify which s
29、ize pipes require bracing for designated seismic design categories and importance factors. Pipe Bracing Seismic Design Category (SDC) IpA, B C D, E, F 1.0Not Required Not Required NPS 3 and Larger 1.5Not Required NPS 2 and Larger NPS 1 and Larger (Source: ASCE 7, Section 13.6.8; with additional exem
30、ptions from Section 13.1.4) Trapeze Supported Pipe Bracing Seismic Design Category (SDC) IpA, B C D, E, F 1.0Not Required Not Required *10 lbs./ft. and Greater 1.5Not Required *10 lbs./ft. and Greater *10 lbs./ft. and Greater (Source: ASCE 7, Section 13.6.8; with additional exemptions from Section 1
31、3.1.4) NOTES: * Required if any pipe is NPS 2 and larger. * Required if any pipe is NPS 3 and larger. * Required if any pipe is NPS 1 and larger. 3.1.2 The Seismic Design Category (SDC) and Component Importance Factor (Ip) are typically found on the project structural drawings or the project specifi
32、cations. In general, the Engineer of Record determines these parameters. 3.1.3 Seismic Design Category (SDC) is a classification assigned to a structure based on its Occupancy Category and the severity of the design earthquake ground motion at the site, as defined in Chapter 11 of ASCE 7. BRACING FO
33、R PIPING SYSTEMS: SEISMIC WIND DYNAMIC DESIGN, SELECTION, AND APPLICATION MSS STANDARD PRACTICE SP-1272 3.1.4 All non-structural components are assigned a Component Importance Factor (Ip) of 1.0 or 1.5 based on their function. The default value is 1.0, but is increased to 1.5 if the component is req
34、uired to function for life-safety purposes after an earthquake, contains hazardous materials, or is in or attached to an Occupancy Category IV structure (essential facility as defined in ASCE 7) and is needed for the continued operation of the facility or its failure could impair the continued opera
35、tion of the facility. 3.2 All piping systems subject to wind loading shall be braced for wind forces in accordance with the requirements contained in this Standard Practice unless otherwise defined in the local building codes or other regulations. 3.3 Bracing of fire sprinkler systems shall be in ac
36、cordance with NFPA 13, and as required by the applicable building code. 3.4 All piping systems subject to other dynamic loading shall be braced as required (see Section 4.25.3). 3.5 Bracing shall not be required for the following conditions: a) Where piping is supported by individual hangers and eac
37、h hanger in the piping run is 12 in. (305 mm) or less in length from the top of the pipe to the supporting structure. Where rod hangers are used they shall be equipped with swivels, eye nuts, or other devices to prevent bending in the rod. b) Where piping is supported on a trapeze and the trapeze is
38、 supported by hangers having a length of 12 in. (305 mm) or less. Where rod hangers are used they shall be equipped with swivels, eye nuts, or other devices to prevent bending in the rod. 4. GENERAL REQUIREMENTS 4.1 Piping systems shall be braced to resist both lateral and longitudinal horizontal fo
39、rces. 4.2 Lateral seismic bracing shall be spaced at a maximum span (Lmax) between lateral braces as provided in Tables 1 and 1M for the expected seismic short period spectral acceleration (SDS). 4.3 Lateral wind bracing shall be spaced at a maximum span (Lmax) between lateral braces as provided in
40、Tables 2 and 2M, or Annexes C and CM for expected basic wind speed (V). 4.4 Each run of pipe shall require longitudinal bracing. Lateral braces shall be allowed to act as longitudinal braces if the bracing is installed within the greater of two (2) ft. (610 mm) or three (3) times the pipe diameter o
41、f a change in direction, provided the lateral brace has the capacity to handle the additional longitudinal load. 4.5 Expansion and contraction of piping systems shall be considered when designing and locating braces. Bracing shall not adversely affect the thermal movement of the piping system. 4.6 E
42、ach offset in a pipe run that is greater than 1/16 of the maximum brace spacing shall be braced. 4.7 The longitudinal bracing requirement for an individual location may be more severe than those addressed in Sections 4.4 and 4.5, as in the case of water hammer or sudden stoppage of flow. 4.8 Braces,
43、 where required, shall be installed at or as close as practical to a hanger location. 4.9 Where practical, bracing should be concentric. All parts and fittings making up the bracing assembly should act in a straight line to avoid eccentric loading on component parts and fasteners. 4.10 Because a bra
44、ce may act in compression as well as tension, it is necessary to size the brace to prevent buckling. This does not apply to cable braces, which act in tension only. 4.11 For individual braces, the slenderness ratio (l/r) shall not exceed 200, where “l” is the effective length of the brace and “r” is
45、 the least radius of gyration. 4.12 Piping systems incorporating vibration-isolation and control devices may not be braced with rigid braces that would transmit the vibration to the building structure. MSS STANDARD PRACTICE SP-1273 The use of slip fittings or isolation grommets/washers, may be used
46、in the design of the bracing assemblies to interrupt the vibration path. 4.13 Cable bracing shall be in accordance with Figure 1. 4.14 Steel cables/wire rope assemblies shall be in accordance with ASTM A1023/A1023M. Stainless steel cables shall comply with ASTM A492. 4.15 When cables are used for br
47、aces, they shall oppose each other in order to provide bracing for forces acting 180 degrees apart. Cables shall be tightened to remove slack, except as provided in Section 4.12. 4.16 A cable seismic brace should have independent cables attached from structure to the braced service (e.g., piping, et
48、c.) to resist the opposing seismic force created during an event. In the case of a lateral or longitudinal (traverse) only seismic brace, this will be two (2) independent cables. In the case of a four-way brace, this will be four (4) independent cables. A continuous cable simply wrapped around the p
49、ipe and attached to two structural attachment points is not an acceptable method of bracing. 4.17 A length of pipe shall not be braced to parts of a building (e.g., walls, ceilings, floors, etc.) that may respond differently during dynamic loading (seismic or other). For example, a length of pipe shall not be braced across building or structure seismic joints. 4.18 The last length of braced pipe shall be provided with a lateral brace at the end of the run. 4.19 C-type clamps, including top beam clamps such as ANSI/MSS SP-58 Types 19 and
