Functional Purposes of Pipe and Hanger Supports

Functional Purposes of Pipe and Hanger Supports

LOOSE SUPPORT

This is most commonly used support meant for supporting only the pipe weight vertically. It allows pipe to move in axial as well as transverse direction but restricts only the vertical downward movement.

LONGITUDINAL GUIDE

This type of support is used to restrict the movement of pipe in transverse direction i.e. perpendicular to length of pipe but allow movement in longitudinal direction. This is also a commonly used type of support. Generally it is used along with Loose support.

TRANSVERSE GUIDE

This type of support is used to restrict the movement of pipe in Longitudinal (axial ) direction but allows the pipe to move in transverse direction. This is also referred as 'AXIAL STOP'. This type is less used as compared to above two types. Generally it is used along with Loose support.

FIXED POINT / ANCHOR

FIX POINT type of support is used to restrict movements in all three directions. ANCHOR type of support is used to restrict movement in all three directions and rotation also in these three directions. 

Non-Welded Type (FIX POINT)

This can be considered as a combination of longitudinal and transverse guide. This type resist only the linear movements in all directions but not the rotational movements. This avoids heavy loading of support as well as pipe. Therefore this type of support is preferred over welded type.

Welded Type (ANCHOR)

This type of support prevents total movements i.e. linear as well as rotational. This type of support is used when it is absolutely essential to prevent any moment/force being transferred further. It causes heavy loading on support as well as pipe. 

LIMIT STOP

As name itself indicates it allows pipe movement freely up to a certain limit and restricts any further movement. This is useful when total stops causes excessive loading on piping and support or nozzle. This type of support should be used selectively, because of stringent and complicated requirements of design, erection and operation.

SPECIAL SUPPORTS

When we need a pipe support whose construction or functional details are different from the available details, then a special support detail sketch is prepared. The functions of this support can be any combination of above functions.

SUMMARY OF TYPES OF SUPPORTS

A SUPPORT CAN BE

• Simple Rest

• Rigid support

• Spring support

• Simple Guide
• Simple Axial Stop
• Rest and Guide
• Rest and Axial Stop
• Guide and Axial Stop

Three way restraint, that is, Rest, Guide and an Axial Stop

SELECTION OF SUPPORT UNDER DIFFERENT LOAD CONDITIONS

SHOE CLAMPS

SHOE VENDOR SADDLES

SPRINGS

• Variable Springs
• Constant Springs

SWAY STRUTS

HYDRAULIC SHOCK AND SWAY SUPPRESSOR

SHOES CLAMP

Recommended for suspension of hot insulated lines.

SHOE VENDOR SADDLE

Designed to keep insulation from crushing

VARIABLE SPRINGS

Meant to absorb vertical displacement of pipes caused by thermal expansion

HANGING SPRINGS

COMBINATION OF SPRINGS

CONSTANT SPRINGS

Used to support pipes and equipment subjected to vertical movement due to thermal expansion at locations where transfer of stress to other supports or equipment can be critical.

Used where variability of a variable spring exceeds 25%.

The MSS(SP58) standard provides for a tolerance of 6% in the constant load through the travel range.

CARRY THE SAME LOAD ALONG THEIR TRAVEL.

SWAY STRUTS

SELECTION CRITERION

Used to restrain movement of piping in one direction while providing for movement due to thermal expansion or contraction in another direction.

FEATURES

Effective under either tensile or compressive force. Can be installed in any spatial orientation.

SWAY STRUT IN VERTICAL ORIENTATION

COMBINATION OF STRUTS

HYDRAULIC SHOCK AND SWAY SUPPRESSOR (SNUBBER)

SELECTION CRITERION

For use on piping systems or equipment when unrestrained thermal movement must be allowed, but which must be restrained during impulsive or cyclic disturbance.

Preferred usage, with standard settings, to prevent destructive results due to earthquakes, flow transients, or wind load. For absorbing the continuous thrust resulting from safety valve discharge blow-off.

EXAMPLES OF SNUBBERS

MECHANICAL SNUBBER

HYDRAULIC SNUBBER

Summary

Supports are needed to limit stress and sag in the pipe to acceptable limits.

Dead load, live load, wind, seismic and hydro test loads need to be considered while designing supports.

Rest, guide and axial supports are the three basic schemes of supporting. A combination of any two or all three may be used for supporting.

High temperature, high pressure and associated phenomena make the steam system supporting critical.

Different type of supports are available under different types of loading conditions.

PIPING SUPPORT ELEMENTS

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