m-2-3 hangers and supports

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Pipe Support Standards

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  • SOUTHERN COMPANY SERVICES M-2-3 ENGINEERING STANDARDS AND GUIDELINES MECHANICAL PIPE HANGERS AND SUPPORTS

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    Pipe Hangers and Supports

    Index

    1.0 INTRODUCTION

    1.1. Purpose 1.2. Scope

    2.0 DEFINITIONS 3.0 CODES AND STANDARDS 4.0 DESIGN CRITERIA AND GUIDELINES

    4.1. Component Designation 4.2. Loads 4.3. Pipe Stress 4.4. Welds 4.5. Support Spacing 4.6. The Pipe Support Contractor and Support Details 4.7. Pipe Support Callout 4.8. Specialty Supports 4.9. Support Placement Tolerance

    5.0 PIPE SUPPORT TYPES AND COMPONENTS RIGID SUPPORTS

    5.1. Rod Hangers and Components 5.1.1 Beam Attachments 5.1.2 Hanger Rods 5.1.3 Turnbuckles 5.1.4 Clamps 5.1.5 Welds 5.1.6 Trapeze Hangers

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    5.1.7 Riser Clamps 5.1.8 Washer Plates

    5.2. Pipe Shoe and Stanchion Supports 5.3. Guides 5.4. Limit Stops 5.5. Anchors 5.6. Welded Pipe Attachments

    6.0 PIPE SUPPORT TYPES AND COMPONENTS ENGINEERED SUPPORTS

    6.1. Variable Spring Hangers 6.2. Constant Supports 6.3. Design of Supplemental Steel

    7.0 REFERENCES

    Appendices

    Appendix A Standard Support Details Appendix B Supplemental Steel Appendix C FRP Standard Support Details Appendix D HDPE Standard Support Details Appendix E Pipe Support Guidelines; FRP & HDPE Pipe

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    REVISION PAGE 1.0 REVISION 1 1.1 Index:

    Added sub section 4.9 in section 4.0 Added Appendix C: FRP Standard Support Details Added Appendix D: HDPE Standard Support Details Added Appendix E: Pipe Support Guidelines; FRP and HDPE Pipe in section 7.0

    1.2 Appendix A:

    Added Rigid Base Support details RBS-10 through RBS-16 in section 2.0 Added Rod Hanger detail RHS-5 in section 3.0 Added Guide Base Support details GBS-12, GBS-13 and GBS-14 in section 4.0 Added Anchor Base Support details ABS-7, ABS-8 and ABS-9 in section 6.0

    1.3 Appendix B:

    Added detail 1D in section 2.0 Added detail 5G in section 6.0 Added details 7F, 7G, 7H, 7J, 7K and 7L in section 8.0 Added details 8H and 8J in section 9.0 Added detail 11B in section 12.0 Added detail 12B in section 13.0

    1.4 Added Appendix C: FRP Standard Support Details 1.5 Added Appendix D: HDPE Standard Support Details 1.6 Added Appendix E: Pipe Support Guidelines; FRP & HDPE Pipe

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    PIPE HANGERS AND SUPPORTS 1.0 INTRODUCTION 1.1 Purpose

    This document provides a guideline for the design of pipe supports. The document is not intended to supersede project specific design criteria but to reflect current SCS practices.

    1.2 Scope

    This standard shall apply to pipe supports for piping systems ranging in size up to 24 inches, unless noted otherwise.

    For the purposes of this standard, pipe supports have been divided into two main categories: Rigid Pipe Supports Application where rigid pipe hangers are acceptable.

    Design Engineering shall be responsible for the location and selection of rigid pipe hangers. Generally, after the engineer has identified the type and location of rigid supports, the detailer shall use the guidelines in section 5.0, Pipe Support Types and Components Rigid Supports, to provide detailed support design.

    Engineered Supports Application where support flexibility must be designed into the piping system by providing variable springs, constant supports and/or rigid hangers, or the support design is critical to the system.

    Design Engineering shall be responsible for the design of engineered pipe hangers and supports. Design criteria and guidelines are given in section 6.0 of this standard. Engineered supports shall be specified after a thorough pipe stress analysis has been performed, unless noted otherwise. See Mechanical Standard M-2-2, Piping Stress Analysis.

    NOTE

    Piping systems containing engineered supports shall be designed as an engineered system of supports. Therefore, the engineer and detailer shall refer to section 5.0, Pipe Support Types and Components Rigid Supports, of this standard, when rigid type supports are required as part of the engineered pipe support system.

    2.0 DEFINITIONS

    The following definitions are applicable to new generation, environmental, and retrofit projects.

    2.1 Piping System Category Indicates the piping systems criticalness of service as defined

    in Pipe Class Criteria found in appendix A of Piping Design Standard M-2-1. In general, there are the following three categories:

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    2.1.1 Category 1/Critical Systems - These systems include main steam, hot and cold reheat, boiler feed-water pump suction, and discharge. The failure of any of these systems will result in the loss of generation capability and/or substantially impact the safety of plant personnel.

    2.1.2 Category 2/Intermediate Systems - These systems include extraction steam, high pressure heater drains, or condensate systems. Failure of any of these systems has less impact on the loss of generation capability or personnel safety.

    2.1.3 Category 3/Non-critical Systems - All other systems such as floor drains, cold water

    systems, potable water, plant service water, vents, or circulating water. Failure of any of these systems has no impact on generation capability.

    2.2 Design Load - This is the pipe load used in the design of the pipe support. It is the higher

    of the load cases for the piping system.

    2.3 Operating Load - This is the pipe load that acts on the support when the system is in service. This load is the algebraic sum of weight load and thermal load. Operating load is equal to hot load for spring hangers.

    2.4 Hydrostatic Load - This is the pipe load acting on the support during hydrostatic testing of the piping system. Hydrostatic loads are often much higher than design loads for steam and gas piping systems.

    2.5 Sustained Load - This is the sum of the weight of the pipe, contents, and pipe support attachment components plus the pressure acting on the system.

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    2.6 Minimum Load - The support shall be designed for the minimum load if the design load is less than the minimum load. The table below (reprinted from MSS SP-58 Pipe Hangers and Supports Materials and Fitting Industry) suggests the minimum design loads based upon the pipe size. This minimum load should be used in designing supplemental steel.

    MINIMUM DESIGN LOADS

    (From MSS SP-58 Pipe Hangers and Supports Materials and Fitting Industry)

    Nominal Pipe Size (in) Load (lb) 3/8 150 150 150 1 150 1 150 1 150 2 150 2 150 3 200 3 210 4 250 5 360 6 480 8 760 10 1120 12 1480 14 1710 16 2130 18 2580 20 3060 24 3060

    2.7 Thermal Load - Stresses imposed on the piping system due to expansion or contraction

    (or both) of the components due to a wide range of temperatures. 3.0 CODES AND STANDARDS

    Pipe support design is governed by the codes and standards that apply to the piping system. The piping codes used in new generation, environmental, and retrofit projects have provisions for the design of pipe supports. The designer should be familiar with the support design portions of the applicable codes listed in section 7.0 References.

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    4.0 DESIGN CRITERIA AND GUIDELINES 4.1 Component Designation

    For the purpose of design standardization all support component designations shall be based on the Anvil International, Inc. Pipe Hangers Catalog numbering system.

    4.2 Loads Supports shall be designed for the most severe conditions of coincident pressure, weight, temperature, and any fluid dynamic events. In addition, piping exposed to wind load, snow, ice, earthquake, or other natural phenomena shall be designed for such loading.

    4.3 Pipe Stress

    Critical piping systems, Piping Category 1, 2, or otherwise designated due to piping loads, shall be stress analyzed in accordance with Mechanical Standard M-2-2, Piping Stress Analysis. The pipe support engineer and designer shall base pipe support selection and design on results from the pipe stress analysis.

    4.4 Welds Welding or bolting attachments to the building or pipe rack structural steel shall be done in accordance with the latest edition of the AISC Manual of Steel Construction Allowable Stress Design. Maximum allowable shear stress in welds shall be limited to 80 percent of the maximum allowable stress of the weaker of the base metals being joined. Maximum allowable tension and bending stresses in welds shall be limited to the maximum allowable stress of the weaker of the base metals being joined.

    4.5 Support Spacing Horizontal piping shall be supported such that excessive sag, bending, or shear stress is minimized. Special consideration will be given where components such as flanges and valves impose concentrated loads. Vertical piping shall be supported with riser clamps. See section 5.1.7 Riser Clamps for spacing of vertical restraints. Supports for piping 3 inches or larger shall be designed and detail