pipe support

DESIGN GUIDE FOR PIPE SUPPORT


CONTENTS

1.0 OBJECTIVE 31.1 Design Objective as a Civil/Structural Engineer 31.2 PIPE SUPPORT OBJECTIVE 3

2.0 CODES, STANDARDS AND REFERENCE BOOKS, DOCUMENTS IN THIS GUIDE 4

3.0 ABBREVIATION 44.0 PIPE SUPPORTS DUTY 55.0 PIPE SUPPORTS LOCATION 56.0 TYPES OF PIPE SUPPORTS 5

6.1 Rigid Support 56.2 Spring support (BY PIPING) 96.3 Snubber /shock absorber (BY PIPING) 106.4 SUPPLEMENTARY STEEL 10

7.0 RESPONSIBILITY 117.1 BY PIPING 117.2 BY CIVIL 117.3 PIPE SUPPORT ON PIPERACK 11

8.0 SUPPORTS (RESTRAINT) 129.0 INPUT PIPING DESIGN LOADS TO STAAD-PRO 12

9.1 LOADS ON PIPE SUPPORT MODEL 129.2 HYDROSTATIC TEST LOAD 129.3 SUSTAINED LOAD 129.4 OPERATION LOAD 139.5 OPERATION AND WIND LOAD 139.6 FRICTION LOAD 13

10.0 TYPES OF SUPPORTS (IMAGE) 1511.0 AXIS OF DIFFERENT BETWEEN PIPING & CIVIL (STAAD-PRO) 1712.0 INPUT AND OUTPUT SIGN 1813.0 DESIGN PARARMETER 1814.0 CLIPS LOADING TO VENDOR 19

14.1 CONSTRUCTABILITY EXAMPLE 1915.0 SCOPE OF WORKING RESPONSIBILITY 1916.0 CONNECTION OF PIPE SUPPORT 19


1.0 OBJECTIVE

The design guide for pipe support is to provide the Civil Engineer to consider the

design and construction of the design processes.

(The specification mainly described as on pipe rack and attached on the vessel)*

1.1 Design Objective as a Civil/Structural Engineer

Civil/Structural Engineers need to know how difficult to design pipe support with a safe

& economical design to support the piping loads, especially when final piping drawings

are not available. Civil/Structural Engineers are last to get all the information but the first group required to produce construction drawings to meet the specifications and schedules.

1.2 PIPE SUPPORT OBJECTIVE

The layout and design of piping and its supporting elements shall be directed toward

preventing the following:

a) piping stresses in excess of those permitted in this Code

b) leakage at joints

c) excessive thrusts and moments on connected equipment (such as pumps and

turbines)

d) excessive stresses in the supporting (or restraining) elements

e) resonance with imposed or fluid-induced vibrations

f) excessive interference with thermal expansion and contraction in piping which is

otherwise adequately flexible

g) unintentional disengagement of piping from its supports

h) excessive piping sag in piping requiring drainage slope

i) excessive distortion or sag of piping (e.g., thermoplastics) subject to creep

under conditions of repeated thermal cycling

j) excessive heat flow, exposing supporting elements to temperature extremes

outside their design limits


2.0 CODES, STANDARDS AND REFERENCE BOOKS, DOCUMENTS IN THIS GUIDE

ASME 31.1 & 31.3 Power Piping & Process Piping

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

MSS SP-69 ANSI/MSS Edition Pipe Hangers and Supports - Selection and Application

MSS SP-77 Guidelines for Pipe Support Contractual Relationships

MSS SP-89 Pipe Hangers and Supports -Fabrication and Installation Practices

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

PIPING AND PIPE SUPPORT SYSTEMS

(Paul R.Smith, P.E & Thomas J. Van Lann, P.E)

3.0 ABBREVIATION

SPS - Special Pipe Support

HYD - Hydro test

SUS - Suspension

OPE - Operation

OPE+Wind - Operation with Wind

FRIC - Friction

SW - Self-Weight

DL - Dead Load

LL - Live Load

VDB - Vendor Data Base

VDBC - Vendor Data Base Comment

IDC - Internal Discipline Check

IFR - Issued For Review

IFC - Issued For Construction


4.0 PIPE SUPPORTS DUTY

Support piping system loads Restrain or guide piping system elements Permit movement of our piping system Transmit pipe loads to structural members Prevent heat transfer to the surrounding structure To carry load To ensure that material is not stressed beyond a safe limit Holdup of liquid can occurred due to pipe sagging (allow draining) To permit thermal expansion To withstand and dampen vibrational forces applied to the piping

5.0 PIPE SUPPORTS LOCATION

(On pipe racks & vessel)* Near grade on sleeper In trench Near steelwork or equipment

6.0 TYPES OF PIPE SUPPORTS

1. Rigid Support 2. Spring Support 3. Snubber /shock absorber 4. Supplementary steel

6.1 Rigid Support

Rigid supports are used to restrict pipe in certain direction(s) without any flexibility (in

that direction).

Main function of a rigid support can be Anchor, Rest, Guide or both Rest & Guide. For supporting elements shall be based on the loadings: including the weight of the

fluid transported or the fluid used for testing, whichever is heavier.

Exceptions may be made in the case of supporting elements for large size gas or air

piping, exhaust steam, relief or safety valve relief piping, but only under the conditions

where the possibility of the line becoming full of water or other liquid is very remote.


Stanchion/Pipe Shoe

Rigid support can be provided either from bottom or top. In case of bottom supports generally a stanchion or Pipe Clamp Base is used. It can be simply kept on steel structure for only rest type supports. To simultaneously

restrict in another direction separate plate or Lift up Lug can be used.

A pipe anchor is a rigid support that restricts movement in all three orthogonal directions and all three rotational directions, i.e. restricting all the 6 degrees of freedom. This usually is a welded stanchion that is welded or bolted to steel or concrete. (In case of anchor which is bolted to concrete, a special type of bolt is required called Anchor Bolt, which is used to hold the support with concrete.) Resting

To support the pipe weight & is generally used where little or no pipe movement is anticipated.

Guides

Pipe lines containing expansion joints or other where lateral pipe movement needs to be controlled.

Permits movement along pipe axis Prevents lateral movement May permit pipe rotation Where guides are provided to restrain, direct, or absorb piping movements, their

design shall take into account the forces and moments at these elements

caused by internal pressure and thermal expansion.


Stopper

For pressure testing and stopping all pipework.

Anchor

Full fixation Permits very limited (if any) translation or rotation Where anchors are provided to restrain, direct, or absorb piping movements,

their design shall take into account the forces and moments at these elements

caused by internal pressure and thermal expansion.


Other types of support


Rod Hanger(By Piping)

It is a static restraint i.e. it is designed to withstand tensile load only (no compression load should be exerted on it; in such case buckling may take place). It is rigid vertical type support provide from top only. As it comes with hinge and clamp, no substantial frictional force comes into play.

Rigid Strut(By Piping)

It is a dynamic component i.e. is designed to withstand both tensile and compression load. Strut can be providing in vertical as well as horizontal direction. V-type Strut can be used to restrict 2 degrees of freedom. It consists of stiff clamp, rigid strut,

welding clevis. Selection depends on pipe size, load, temperature, insulation, assembly

length. As it comes with hinge and clamp, no substantial frictional force comes into

play.

6.2 Spring support (BY PIPING)

1. Variable Spring Hanger or Variable Effort Support.

2. Constant Spring Hanger or Constant Effort Support.

Load calculations for variable and constant supports, such as springs or

counterweights, shall be based on the design operating conditions of the piping.

They shall not include the weight of the hydrostatic test fluid. However, the support


shall be capable of carrying the total load under test conditions, unless additional

support is provided during the test period.

6.3 Snubber /shock absorber (BY PIPING)

Dynamic restraint: earthquake, fluid, certain system functions, environmental

influences.

6.4 SUPPLEMENTARY STEEL

Where it is necessary to frame structural members between existing steel members,

such supplementary steel shall be designed in accordance with AISC specifications, or

similar recognized structural design standards. Increases of allowable stress values

shall be in accordance with the structural design standard being used. Additional

increases of allowable stress values, such as allowed stress values are not permitted.


7.0 RESPONSIBILITY

7.1 BY PIPING

Anchors, guide and restraints shall be designed for imposed loading as determined by

the Piping Design Engineer.

For guided systems, in the absence of specified lateral loads, the guide shall be

designed for 20% of the dead weight load based on the spans, with a design load of

50lbs (0.22 kN) as a minimum.

For pressure piping with joints not having a restraining design, other positive restraining

such as clamps, rods and/or thrust blocking shall be used to maintain the integrity of

the joints.

The necessity for, and the location of, shock suppressors and seismic control devices shall be as determined by the Piping Design Engineers scope.

7.2 BY CIVIL

Pipe support is classified as a special pipe support and under the civils responsibility to

design the pipe support when one or more of following criteria are met.

Total vertical load transmitting by piping 3.0MT. Total lateral load transmitting by piping 1.0MT. Height of support 3.0M. All reactions applied to SPS will be provided as a sketch by the Pipe Stress Engineer.

7.3 PIPE SUPPORT ON PIPERACK

A pipe may be supported to resist gravity only, or may have varying degrees of restraint

from guided in a single direction to fully anchored supports.

Pipe stress analysis can be completed for all the pipes located in the pipe rack. This

stress analysis takes into account the support type and location for each support and

provides individual design forces for each pipe at that specific location. These resultant

pipe loads can be used for design. However, application of loads in this manner does

not include additional loads for futures expansion. Therefore, a uniform load at each

level of the rack is typically applied in lieu of actual pipe forces. Local support condition

should also be verified where large anchor forces are present.


8.0 SUPPORTS (RESTRAINT)

Vertical (gravity direction) Axial (parallel to pipe run (longitudinal axis) Lateral (perpendicular to both the vertical & the axial axes(transverse axis)

9.0 INPUT PIPING DESIGN LOADS TO STAAD-PRO

9.1 LOADS ON PIPE SUPPORT MODEL

Dead load (Structure dead load (self-weight)

Live Load (Usually no Live Load on pipe support)

Piping HYD - Hydro test load

SUS - Suspension

OPE - Operation

OPE +Wind - Operation with Wind

9.2 HYDROSTATIC TEST LOAD

The sustained load due to the weight of water required for hydrostatic testing

(especially on large diameter pipes) shall be accounted for in the pipe support and

structural steel designs.

Hydrostatic test loads and stresses are considered short term design conditions. An

extended allowable test stress is permissible unless otherwise noted.

9.3 SUSTAINED LOAD

Sustained load is caused by mechanical forces which are present throughout the

abnormal operation of the piping system. Include both weight & pressure loadings.

(All piping systems must be designed for weight loading)

Many piping systems are under internal pressure loadings from the fluid they transport.

Calculated stresses are due to sustained load by

(a) Internal Pressure Stresses.

(b) External Pressure Stresses.

(c) External Loading Stresses.


9.4 OPERATION LOAD

The sum of the stresses produced by internal and external pressure, live and dead

loads during operation.

9.5 OPERATION AND WIND LOAD

The sum of the stresses produced by internal and external pressure, live and dead

loads during operation and wind.

9.6 FRICTION LOAD

Caused by hot lines sliding across the pipe support are assumed to be partially resisted

by nearby cold lines.

Friction forces can be estimated based on the coefficient of friction between the pipe

shoe and support beam.

Friction loads are cause by expansion and contraction of pipes.

Based on the expansion and contraction of pipes, friction loads are typically seen in the

longitudinal direction of the pipe support.

(When a pipe expands due to increase in temperature from the installed condition,

some friction forces will be transferred to the line-stops and rest supports tending to

move them in the same or opposite direction of the thermal expansion. It is advisable

that the pipe stress analyst do not list the friction forces in the load table on the stress isometric.

The reason is that this has led to that the friction load has been misunderstood by the

pipe supporter or structural department, and hence a line-stop has been installed

where the pipes were to move freely in the axial direction. Guidance should be given to the pipe support department on how to handle friction

forces not listed on the stress isometric. Typical is to add an axial friction load of 1/3 of the reported vertical loads.)1 Note1 RECOMMENDED PRACTICE DET NORSKE VERITAS DNV-RP-D101

STRUCTURAL ANALYSIS OF PIPING SYSTEMS

So, we have to consider additional friction load which is need to consider for local

strength check and this load is acting along longitudinal axis of the pipe.

Friction load need to consider when pipe support is rest, or guide or rest +guide.

Friction load is calculated as:

Friction Load (FRIC) = Static Friction Coefficient x Operating Load (OPE)


Where static friction coefficient between steel to steel

= 0.3 and Operating load acting vertically (gravity direction).

Friction has been described from each. Detailed Engineering Design Data for Civil and

Structure" Project specification


10.0 TYPES OF SUPPORTS (IMAGE)


11.0 AXIS OF DIFFERENT BETWEEN PIPING & CIVIL (STAAD-PRO)

Axis from Pipe Stress Engineer

Designing from Civil Engineer

Note

So there need to convert the load axis when putting the piping load to pipe support

model.

And then we need to change axis for giving the clip loading to the Vendor.


12.0 INPUT AND OUTPUT SIGN

There need to do the model for of horizontal loadings to be safe side.

There also need to give the result of horizontal clip loadings to be safe side.

13.0 DESIGN PARARMETER

Actually need to design parameter as the project specification.

Generally the basic of design parameter are as under described.

CODE - CODE as under project

ALPHA - Factor for combined bending and axial force checks BEAM - Number of selections to be checked per beam

BETA - Factor for combined bending and axial force checks CMM - Loading Type

CMN - End Restraint

FU - Ultimate tensile strength of steel

PY - Yield stress of steel

SBLT - Select type of section

TORSION - Method to be used for a specific member or group of

members

RATIO - Permissible ratio of applied loading to section capacity

KY - K value in local Y axis for slenderness value KL/r

KZ - K value in local Z axis for slenderness value KL/r

LY - Length in local Y axis for slenderness value KL/r

LZ - Length in local Z axis for slenderness value KL/r

UNL - Unrestrained member length in lateral torsion buckling

checks


14.0 CLIPS LOADING TO VENDOR

14.1 CONSTRUCTABILITY EXAMPLE

Especially difference of beam depth is less than 100mm, it will bring narrow space not be able to able to work welding grinding coating and inspection.

Same depth could be selected provided that; The difference of depth (h) shall be kept over minimum 100mm for ease

connection from constructability point of view.

Any narrow spaces shall be avoided as much as possible.

15.0 SCOPE OF WORKING RESPONSIBILITY

Only beam and bracing from Vessel and Pipe rack are under Civil Scope.

Unless noted otherwise, other parts are under Piping Scope.

16.0 CONNECTION OF PIPE SUPPORT

The connection of pipe-support to Vessel is under vendor responsibility.

We need to give the clips loading to Vendor by VDB.

And after checking the clip load and give us comment from VDB.

pipe support

Documents

design of piping

pipe support design

pipe support objective

pipe support model

pipe support contents

connection of pipe support

types of pipe

pipe rack