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GUIDE FOR SPRING HANGER INSPECTION

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THIS GUIDE PRESENTS GENERAL INFORMATION ABOUT THE SPRING HANGER, ITS TYPES AND HOW TO INSPECT THE SPRING HANGER ACCORDING TO RELATED CODES AND STANDARDS.

PIPE HANGER IS DIVIDED INTO TWO GROUPS, RIGID AND SPRING HANGER, THIS GUIDE WILL FOCUS ON THE SPRING HANGER-TYPE.

MORE DETAILS ABOUT THIS SUBJECT IS AVAILABLE IN THE APPLICABLE REFERENCES.

INTRODUCTION


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Pipe Hanger: Is a device which is suspended from a structure and is used to carry the piping load in tension.

Types of Pipe Hangers

a. Rigid Hanger: A pipe hanger which does not permit vertical movement. b. Spring Hanger: A Pipe Hanger, using a spring or springs to, permit vertical

movement in a piping system.

INTRODUCTION: Spring supports sustain a pipe that has undergone displacement. Simple supports are no longer useful if the pipe rises off and loads are transferred to other supports or fragile equipment nozzles. To ensure support for the pipe as it moves, a support to compensate movement is desired. One very practical device for this is the spring.

Types of spring hangers:

a. Variable- Type Spring Hanger (which is by far the most common): A spring coil device which produce varying supporting effect while permitting vertical pipe movement , Spring supports for this class shall have characteristics so that use at the maximum recommended pipe travel results in a variability factor of not more than 25%.

DEFINITIONS

PIPE HANGERS

SPRING HANGERS


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b. Constant - Type Spring Hanger: A mechanical and spring coil device which produces a relatively constant supporting effect, while permitting vertical pipe movement. This class provides a mean variability (deviation from specified load), including friction, of not more than 6% throughout total travel range.

Cold Setting: The position at which a Spring Hanger indicator is set denoting the proper installation setting of the unit with the piping in the cold position.

Hot Setting: The position at which the indicator on a Spring Hanger should be with the piping in the hot or operating position.

Temporary locking devices / Travel stops: A device which temporarily lock the moveable parts of Spring Hanger in a fixed position, enabling a load to be transferred through the Spring Hanger to the supporting structure while maintaining the piping at a desired elevation during Erection and/or Hydrostatic Testing.)

MISCELLANEOUS


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Each hanger assembly should be verified against the hanger drawing to assure that all components have been installed and are in their proper position.

Temporary locking devices (travel stops) and other locking means furnished with spring units should be properly engaged

Spring locking devices and any temporary hangers and supports required for hydrostatic testing shall be removed

Spring hangers should be checked to insure that their load/travel indicators are approximately in their cold position setting and that the pipe is at the proper elevation.

Inspection of Spring Hangers

Inspection after installation and -prior to hydrostatic testing

Inspection after hydrostatic testing and -prior to heating up


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Piping systems should be inspected in their entirety to verify that no interference exists between the pipe and or the pipe insulation and the building structure or equipment.

Spring hanger loads should be checked under both cold and hot conditions, and the readings obtained should be checked against the original cold and hot readings.

The plant should establish a program to have a periodic 'Inspection of critical piping support system and load travel indicator readings recorded and compared to the base line set of readings.

Spring hangers should be checked to ensure that their load/travel indicators are approximately in their hot position setting and that the pipe is at the proper elevation.

Line temperature and actual hot positions of the load/travel indicators on springs should be noted and recorded in a permanent formal log. See attached record log

Note: Although Load travel indicator may not line up exactly with the base line readings, the hanger may still be considered functional if the reading is close to the base reading.

Inspection of in service spring hangers


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To compensate for pipe elevation discrepancies, Hangers are usually provided with means to permit vertical adjustment during and & after installation. Threaded devices using turnbuckles, clevises, etc. provide this feature or the adjustment is inherently available in the hanger design, No adjustment shall be made that will result in less than full usable thread engagement,

Adjustably features also serve to facilitate pipe load distribution.

Constant type springs have specific load adjustment devices, which can vary the spring effort by plus or minus some percentage from the factory set load.

Variable type springs are usually provided with turnbuckles, threaded collars, or adjustment nuts to enable varying the spring effort.

load travel scale on variable and constraint type spring units are usually marked to show the position of the load/ travel indicator in both the cold and hot positions.

Reference should be made to the particular spring suppliers ‘Catalog for the location and operation of these devices.

Adjustment of spring hangers


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MSS-SP-58: Pipe Hangers and Supports - Materials, Design, and Manufacture

MSS-SP-69: Pipe Hangers and Supports - Selection and Application

MSS-SP-89: Pipe Hangars and Supports - Fabrication and Installation Practices

MSS-SP-90: Guidelines on Terminology for Pipe Hangers and Supports

API 574 : INSPECTION PRACTICES FOR PIPING SYSTEM COMPONENTS

SPRING HANGER CATALOGUES.

RFERENCES


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Figure no 1: Locking Devices / Travel Stop


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Record sheet to be used for spring hanger inspection and recording of readings

procedure for spring hanger inspection

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