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MECHANICAL MES-MDDD-6.5ENGINEERING Rev.: 1

GUIDELINE Rev. Date: 03-28-2003Page 1 of 6

This document contains information that is confidential and proprietary to Sargent & Lundy, L.L.C. (S&L). It shall not bereproduced in whole or in part or released to any third party without the prior written consent of S&L. Copyright Sargent &Lundy, L.L.C. 1996 all rights reserved. Standards located on the Intranet at http://SLWEB.SARGENTLUNDY.COM are to beconsidered as the official version of the Standard.

MES-MDDD6-5-REV1.DOC

COMPONENT SUPPORT DESIGN CRITERIA(Entire Guideline Reformatted)

APPROVED: Signature on File

1. PURPOSE

This guideline defines the design criteria that shall be followed by component support

designers for both fossil and nuclear projects, unless otherwise directed by the Project

Manager.

2. DEFINITIONS

2.1. Components - Pressure - retaining vessels in a power plant, such as concrete reactor vessels,

concrete containments, piping systems, pumps, valves, core support structures, storage

tanks, etc.

2.2. Component Support - The entire range of structural and mechanical elements whose functions

include carrying the weight of components and providing them with structural stability during

any postulated loading conditions. Structural elements whose sole function is to carry

dynamic loads caused by a postulated loss of pressure-retaining integrity (i.e., pipe rupture

restraints) are excluded.

2.3. Anchor - A component support used to prevent any translational or rotational movement of the

component. A is used to designate an anchor.

2.4. Rigid Support - A device used to prevent translation of component in only one axis. R

designates all rigid supports carrying vertical loads. Rigid supports carrying loads other than

vertical are designated by X. X supports are also commonly referred to as rigid restraints.

2.5. Guide - A component support used to prevent translational movement of a pipe in two

directions except axial to the pipe. G designates a guide.

2.6. Constant Support - A spring-type vertical support used to carry weight loads at locations

subject to relatively large vertical thermal movement and at locations where a substantially

uniform supporting force throughout the travel range is required. C designates a constant

support.

2.7. Variable Support - A spring-type vertical support used to carry weight loads at locations

subject to vertical thermal movement and at locations where some variation in the supporting

force may be allowed. V designates variable supports.

2.8. Snubber or Shock Arrestor - A device used as a shock and vibration arrestor that allows

thermal movement of the component but locks and acts as a rigid restraint when subjected to

acceleration motion or force along its axis. S is used to designate a snubber.

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2.9. Load Capacity Data Sheet (LCDS) - Certified document issued by the vendor which includes

load carrying capacities, load directions, and dimensions of component supports. The LCDS

also identifies the file locations of the calculations and test results performed in the

qualification. The LCDS may consist of one or more pages accompanied by a cover sheet

stamped by the Vendors engineer.

2.10. Integral Attachments - Any attachments welded to, cast with, or forged to the pressure-

retaining component, such as lugs, stanchions, ears, rings and skirts, that transmit the loading

induced by the component.

2.11. Nonintegral Attachments - These are support elements that mechanically connect to the

integral attachments or to pressure-retaining components and transmit the loading induced by

the component. Nonintegral attachments include sliding joints, clamps, cradles, saddles, or

straps.

3. PROCEDURES AND INSTRUCTIONS

3.1. General Design

3.1.1. Component supports shall be designed consistently with the results of the piping subsystem

analysis as to the type of support and the magnitude and direction of loads and movements.

3.1.2. Component support design shall be in accordance with governing codes as follows.

For S&L Class A, B, and C (ASME Section III, Classes 1, 2, and 3, respectively)

components, the design shall be per Subsection NF of Section III of the ASME Boiler and

Pressure Vessel Code. Supports for these components are termed safety-related

supports.

For S&L Class D (ANSI/ASME B31.1) components, the design, in general, shall be per

ANSI/ASME B31.l. Supports for these components are termed non-safety-relatedsupports.

For the purpose of defining the jurisdictional boundary between piping supports and the

building structure, the following definition shall apply when Subsection NF is invoked.

- Structural members shown on the civil structural drawings of the plant and analyzed

in the building structural analysis may be designated building structure even though

these members are located in the piping or component support load path.

- Structural members installed and used for the primary purpose of supporting piping

or components shown on mechanical system drawings shall be designated

component supports and shall be constructed according to the defined jurisdictional

boundary for a particular project.

3.1.3. The component support design configuration shall be simple, economical, and constructible

based on coordination of design requirements with the plant and piping specifications.

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3.1.4. In-place embedment plates and structural steel shall be used for attachments whenever

possible; use of expansion anchor plates shall be minimized.

3.1.5. Special consideration shall be given to hydrostatic testing; temporary support shall be

designed if necessary.

3.1.6. Shear lugs shall be used whenever the line of action of the support using pipe clamp makes

an angle greater than 10, or the angle specified by the clamp vendor, whichever is smaller,

from the line drawn at the point of support perpendicular to the axis of the pipe. MES-EMD-

6.2 shall be used for designing shear lugs.

3.1.7. Rigidrisersupports shall be designedsuch that each arm shallcarry the total support load.

Unequal arm risersupports should be avoided.

3.1.8. The type of support or restraint hardware to be used on either leg of an axial support attached

to a risertype supportshall be designed as follows:

If the support is rigid (R or X) or a snubber (S), each leg shall be designed to carry thetotal load.

If the support is variable or constant, each spring shall be selected to carry the actual

load as determined by weight-balance calculations.

3.1.9. Two or more non-safety-related, nonseismic cold lines (temperatures below 150F) may be

supported on one trapeze beam.

3.1.10. Pipes on a trapeze design shall always be held firmly on the trapeze beam (i.e., use of U-bolt,

box-type, etc.).

3.1.11. In trapeze design, each leg shall be designed to support the actual load as determined by load

balance calculations. For a rigid support, both legs may be designed based on the largerreaction. For variable supports, the trapeze beam should be loaded at mid-span to have

identical spring cans on each leg.

3.1.12. Pin-connected vertical supports (e.g., rod-type, variable, constant, sway strut, etc.) shall be

designed:

So that the range of angular movement of the support between the cold and hot positions

does not exceed a 4 cone centered at the vertical axis or as specified by the vendor, or

With an offset on the upper attachment so that the support is vertical in the hot position.

The maximum angular offset from the vertical in any case is 4.

3.1.13. Sufficient clearance, after thermal movements, shall be provided between the support and the

adjacent components or equipment. Between a support and a dynamically supported

component, a minimum clearance of 3 in. shall be provided, and between a support and a

nondynamically supported component a minimum clearance of 6 in, shall be provided.

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3.1.14. When the support cannot be designed in accordance with the piping system analysis as to the

location or direction relative to the pipe, redesign must be coordinated with the Stress Analyst.

3.1.15. When a component support is attached to any part (standard or nonstandard) of another

support, the affected support shall be qualified.

3.2. Pipe Attachments

3.2.1. Pipe clamps used with the rigid-rod-type, variable or constant support shall be selected as

follows:

Single-bolt clamp (sometimes called two-bolt clamp) or adjustable clevis clamps may be

usedon pipes with insulation 1 in. thick or less.

Double-bolt clamp (sometimes called three-bolt clamp) on pipes with insulation thickness

more than 1 in.

The ordinary double-bolt clamp in the preceding item shall not be used with sway strutsor snubbers. Sway strut and snubber clamps are specially designed to withstand tensile

and compressive loads.

3.2.2. Integral pipe attachments shall be of a material that is compatible with the pipe. (Refer to

MES-EMD-6.2 for specifics.)

3.2.3. Support elements directly in contact with the pipe, not integrally attached.

Shall be of the same material as the pipe if the pipe operating temperature is higher than

500F.

Where wet or corrosive environments are expected, and the pipe and clamp or strap are

made of dissimilar materials, an insulating pad of non-conducting material (such asneoprene or red rubber) shall be placed between the pipe and the support clamp. The

insulating pad material shall be suitable for the operating temperature of the pipe, and theload to be supported.

If suitable insulating pads cannot be obtained, then the clamp or strap material shall be

the same as, or have the same electrode potential as the pipe material.

3.2.4. Insulated piping shall be provided with standard pipe-covering protection saddle except where

special details are indicated or required.

3.2.5. Unless specifically qualified, the standard pipe-covering protection saddle shall not be used as

a sliding element on sliding supports.

3.2.6. U-bolts shall be designed as follows:

If a U-bolt is used as a guide, clearance between the U-bolt and the pipe shall be

provided (usually with the use of jam/hex nuts on both sides of the supporting steel) and

specified, and the combined effect of the tensile and side loads shall be checked.

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If the U-bolt is designed to hold the pipe tight (wrench-tight or torqued) against the

supporting steel (which in turn is rigidly attached to the building structure), the U-bolt is

basically a three-directional support. The combined effect of the tensile, side, and axial

loads shall be checked. Published LCDS for U-bolts with ratings in three directions shall

be checked.

If the U-bolt is used to hold the pipe on the trapeze beam of a pin-connected trapeze

design, it shall be loaded only in tension.

3.3. Standard Support Elements

3.3.1. Standard support elements shall be selected from an approved and qualified manufacturers

catalog or LCDS for nuclear power plant applications.

3.3.2. In no case shall hanger rods smaller than 3/8 in. diameter be used for supporting 2 in.

diameter and smaller pipes, or shall hanger rods smaller than 1/2 in. diameter be used for

supporting 2-1/2 in. diameter or larger pipes.

3.3.3. Rod-type supports shall be used only for vertical downward loads.

3.3.4. Variable spring supports shall be designed for the following maximum variations in supporting

effect for the total vertical travel between hot and cold positions:

+ 6% from the design load for main steam and hot and cold reheat steam piping.

+ 10% from the design load for all other piping having a service temperature of 350F and

higher.

+ 25% from the design load for all other piping.

3.3.5. Constant supports shall be used where the following conditions exist.

Where a large thermal growth cannot be accommodated by a variable spring support.

Where the load variations for a variable spring support exceed + 6% from the design load

or 12% overall.

Constant support shall not be used if the design travel is less than 1/2 inch.

3.3.6. Constant supports shall have a minimum adjustable supporting weight margin of + 10% from

the calculated load and an over-travel margin of not less than 25% but in no case less than

1 in.

3.3.7. Snubbers shall be initially selected such that the stroke or total travel shall be at least 20%

greater than the actual travel. Where the actual travel (caused by pipe thermal movements) is

less than 1/8 inch, a detailed review for applicability shall be made prior to the design.

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3.3.8. Where possible, the cold and hot settings of snubbers shall be equidistant from the middle of

the stroke.

3.3.9. Two lengths of rods shall not be joined by welding. Threaded rod coupling or turnbuckle shall

be used.

3.4. Auxiliary Steel and Structural Attachment

3.4.1. When attaching to the top or bottom flange of in-place beams, welding across the flange is not

allowed. Welds shall be per AISC or Section III of the ASME Boiler and Pressure Vessel

Code.

3.4.2. Cantilever design attached to embedment plate shall always be checked against the pullout

capacity of the embedment plate, as specified by the Responsible Structural Engineer.

3.4.3. For the preliminary selection of auxiliary steel, use SDS- E37, Mechanical Component

Auxiliary Support Steel Framing, if the seismic accelerations do not exceed 4g along the

vertical or 2g along the horizontal.

3.4.4. Welds parallel to the edge of an in-place embedment plate shall not be closer than 1-1/2 in.

from the edge of the embedment plate.

4. REVISIONS

Revisions to the design criteria shall be processed in the same manner as the original.

5. REFERENCES

5.1. AISC Steel Construction Manual.

5.2. ANSI/ASME B31.1, Power Piping Code.

5.3. ASME Boiler and Pressure Vessel Code, Section III, Subsections NF and NCA.

5.4. SDS-E37, Mechanical Component Auxiliary Support Steel Framing.

5.5. MES-EMD-6.2, Evaluation of Welded Attachments.

5.6. MES-4.11, Numbering System for Pipe Supports.

5.7. MES-MDDD-6.13, Preparation of Component Support Design Drawings.

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