An Introduction to Pipe Supports
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Contents Introduction Supports are Necessary? Necessary? Why Pipe Supports Codes and Standards of Pipe Supports Design and Selection of Pipe Supports Layout Considerations for Supporting General Support Terminology and basic function Types of Supports Supports Support Span for Rack Rack Piping Typical Support A brief about Spring Hanger Supports Pipe Support Manufacturers
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Introduction :
Piping systems -Major Part of any hydrocarbon industry.
Pipes as irregular space frames –usually not self supporting.
Proper pipe support knowledge during layout stage is advantageous.
Loads to be transmitted from pipe to supporting structures with the help of pipe supports.
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Why Pipe supports are necessary ? To prevent…..
Pipe stresses in excess to allowable.
Leakages in joints.
Line Vibrations.
Failure against Seismic and Wind loading.
Unintentional disengagement of piping from it’s supports. 7/12/2013
Why Pipe supports are necessary (Cont..) ? To prevent… • Excessive pipe sag. • Exposure of elements to temp extremes, outside their design limit. • Undesirable line movements to protect sensitive equipment against overloading.
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Codes and Standards on pipe supports.
MSS-SP-58- Establishes the material, design, and inspection criteria to be used in the manufacturing of standard pipe supports. (USA)
MSS-SP-69- Provides recommendations for the selection and application of pipe supports. (USA)
MSS-SP-89- Provides recommendations for the fabrication and installation of pipe supports. (USA)
BS-3974- Specification of pipe supports 1, 2, 3. (UK)
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Codes and Standards on pipe supports (Cont..)
VGB-R-510 L- Standard supports guidelines. (Germany)
RCC-M- Specifications for pipe supports. (France)
MITI 501- Technical regulations (Japan)
Various Pipe Support Manufacturers Catalogue (PTP/C&P /Lisega/ PSIL/ Sarathi etc)
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Design and selection of pipe supports The complex requirement of today’s support elements:
Reliable functioning
Maintenance free operation
Economic and easy installations
Quick delivery of components and low unit prices
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Design and selection of pipe supports (Cont..) Major Criteria governing support hardware : • Support function, • Magnitude of expected load, • Space limitations, • Design temp of piping system,
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Design and selection of pipe supports (Cont..) Major Criteria governing support hardware ( Cont.. ) :
• Expansion effects of piping systems. • Piping attachment and supporting structure material compatibility. • Piping insulation. • Suitability to environment. • Ease of operation, inspection and installation
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Layout considerations for Supporting.
Group pipe lines to minimize the number of structures needed . Route lines close to the possible point of supports ( i.e. grade or structure which is provided for other purposes.) Supports or braces to be located at or near neutral pts. (thermal null pts) Supports to be located as near as possible to concentrated loads such as valves, flanges, heavy actuators etc. Piping susceptible to vibration such as compressor connected lines to be supported independently. The use of hold down or similar supports offering resistance to motion and providing some damping capacity to be used rather than hanging type supports. 7/12/2013
Layout considerations…..
Piping connected to top of vessel to be advantageously supported from the vessel to minimize relative movement between supports and piping.
Always maintain the distance between supports as per project specification recommended support span table. ( it is applicable to straight run pipe length only.) When change of direction in a horizontal plane occur, it is suggested that the spacing be limited to ¾ times the standard pipe span.
Sufficient space to be provided to facilitate support assembly installation, inspection and maintenance. 7/12/2013
General support terminology and basic function.
Restraint- Any device that prevents, resists, or limits the free thermal movement of piping. Brace- A device primarily intended to resist displacement of piping due to forces other than thermal expansion and gravity. Anchor- A rigid restraint providing substantially full fixation. Stop- A device which permits rotation but prevents translatory movements of piping. Guide- A device which prevents the rotation about one or more axis due to bending moment or torsion. Hanger- A support by which piping is suspended from a structure which functions by carrying piping load in tension/Compression. 7/12/2013
General supports……
Resilient support- A support which includes one or more largely elastic members to carry pipe sustain + thermal loads at the same time allowing pipe thermal movement in the desired direction. Sliding support- A device which is provided below piping to take gravity loads, offering no resistance other than frictional to horizontal motion. Rigid support- A support providing stiffness in at least one direction, comparable to that of the pipe. Damping element- A device which increases damping of a system offering high resistance against rapid displacement, caused by dynamic loading while permitting essentially free movement. 7/12/2013
Types of Supports
Hanger Supports – 1) Variable Hanger 2) Constant Hanger 3) Rigid Hanger. Dynamically Loaded Supports – 1) Struts 2) Snubbers 3) Sway Brace 4) Energy absorbers 5) Pipe Clamps 6) Pipe whip / Hold down restraints. Pipe Bearing Components – 1) Pipe Saddle 2) Pipe Shoe ( welded/ clamped ) 3) Pipe Trunnion 4) Wear Pad. Threaded Members – 1) welding nut 2) welded beam attachment 3) Clevis 4) Turn buckle 5) Tie rod 6) Stud bolt, nut, locknut, spring washers etc. Slide Bearing Plates – Teflon, Stainless steel, graphite. Pipe Supports for Cold Service. 7/12/2013
Typical Support Span for Rack Piping Span table informs maximum support span for rest type supports when running in a Pipe rack.
The Span mainly depends on Material, Material Thickness, Commodity, Insulation thickness, layout, allowable deflection etc.
All span dimensions on the table are in “meter” length.
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Brief About Spring Hangers Variable Spring Hanger Constant Spring Hanger Both the above can be either hanging from top or Mounted from bottom. Main important terms related to Spring Hangers are: Cold Load, Hot Load, Spring Rate, Vertical Travel or Displacement, %Variability, Axial and Lateral Travel, Presetting, Bottoming Out, Elevation Difference etc.
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Pipe Support Manufacturers
18
Piping Technology and Products Ltd (PTP). Carpenter and Paterson Ltd (C&P). Lisega ltd. Binder Group Ltd. Pipe Support India Ltd (PSIL). Sarathi Engg Ent Pvt Ltd.
7/12/2013 Friday, J uly 12, 2013
REAL, J amnagar
Questionnaire
Why pipe supports are required? What is the basic aim of supporting?
List three layout considerations for supporting?
List common types of supports in a piping system?
What do you mean by trunnion support?
As per analysis the nozzle loads on the pump are high due to friction. What is the type of support recommended near the equipment ? 7/12/2013
Questionnaire (Cont..)
For a 10” NB line carrying liquid, Sch std what is the support span if the line is through a rack and having 50mm insulation?
What is the friction co-efficient value between PTFE and polished SS?
What do you mean by hot load and cold load of a Spring Hanger?
Write the equation for Variability? For a variable Spring hanger what is the maximum allowable value of variability as per C&P Catalogue?
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Questionnaire (Cont..)
Which type of support has restraints in all directions and degrees?
A rigid hanger is fixed on a horizontal pipe having 100 mm of travel, the hanger length is 700 mm . Is the design acceptable ?
Spring hangers are basically intended to carry a) Self weight or b) Thermal load?
The heater outlet line is having vibrations. In order to arrest the vibrations which type of restraints are to be used a) Sway Brace b ) Snubbers ? 7/12/2013
Thank You
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