Piping Support activity is critical activity done in conjuction with Pipe Stress Analysis. Pipes must be properly and adequately supported to avoid their structural failures. Many types of supports are employed in a typical process plant to take care of various stresses and strains developed in a piping system due to weight, operating conditions, earthquake and wind.
Loads to be Sustained by Piping Supports
The loads to be sustained by piping supports are calculated by taking into account all following components.
- Mass of conveyed fluid, calculated on the basis of following densities : Gas/Steam/Air : 0, Water : 1000Kb/cu.m. Other Liquids : as per density of that liquid.
- Insulation mass as per its density. 120Kg/cu.m. tentative
- All loads due to thermal expansion and resulting from stress analysis calculations.
- Overloads due to any water hammer or slug forces phenomenon.
- Concentrated loads due to opening of safety valves.
- Overloads due to earthquake, assuming a corrective factor in the piping own mass.
- Wind force.
- Overall mass of piping in hydraulic test conditions, i.e. piping full of water. In this case however, the loads due to wind and earthquake should not be considered. The load due to the hydraulic test is not applied to the supports for lines subject to pneumatic test only.
|* Spans limited by stress (all others limited by deflection). + Pipe walls require …Read More..|
|PTFE Slide Plates These are used where supports with low coefficient of friction (0.1) are required …Read More..|
3D Modelling of Pipe Supports
Piping supports are usually represented in 3D Model by one of the two methods as listed below.
- Logical Modelling : Only point of support is represented in model with the help of a X Mark. A Code is attached to X mark complete with dimensions of support, as per Support identification procedure for the project.
- Physical Modelling : The support is completely modeled with all the components and the indication of identifying code complete with characteristics dimensions.
Typical 3D Modelling programs are PDS, PDMS, SP3D, Autodexk Plant 3D etc.
Indentification and tagging of pipe supports
Identification or tagging of supports on piping system is important for Tracking of Supports for Design, MTO and procurement point of view. Generally support tags includes primary function code of support, other auxiliary codes and dimensions. Here is a example tagging system for supports on a typical project.
Sample Support Function Codes
- A : Anchor
- B : Rigid support like saddle or shoe.
- C : Rigid support except saddle and shoe.
- D: Adjustable Support
- E : Adjustable support with low friction sliding plates.
- F : Axial Stop
- G : Guide
- H : Hanger with tie rod.
- S : Spring Support
- P : Post, portal and bracket, connections on reinforced concrete beam.
- SS : Protecting Plate
- R : Rigid support for pipeline valves.
- U : Rigid of saddle or shoe type for pipelines.
Company Standard Supports
Example : X-NN where X is function code as above and NN is support number from support standard for the project.
Example : B-11 : Clamped shoe for pipes NPS 1/2″ to 24″
Company Standard Structural Member Support
E.g. Tee-Post, U Frame, L Frame etc.
Example : P-04B-1200-1000 where P stands for portal, 04 support number in support standard, B stands for structural member size, 1200 is height of T-post, 1000 width of T-Post top member.
Supports standardized for the Project
Some supports are standardized for the particular project if they are not present in company standard but needs to be repeatedly used. Example coding system can be as follows :
JX-NN where J indicates it is project standard support, X is function code, NN is number given to that support.
Some supports are unique to particular line at particular location. They are not repeated anywhere else in project. Example coding can be :
SPS-X-NNN where SPS means special pipe support, X is a funciton code and NNN is number given to that support in support register.
Reinforcement Plates / Protection Plates
Example tagging system can be :
SS-NN where SS means reinforcement plate, NN is number given in company support standard.
Special Items Supports e.g. Springs
Special support items like springs can be given special codes e.g.
XX-NNN where XX can be code as follows :
- VS : Variable Load Spring
- CS : Constant load Spring
- SA : Shock Absorber
- RS : Rigid Strut
Sample coding for support foundations can be as follows :
E-2-1050-200 where E : foundation type, 2 : Plinth Type, 1050 : Plinth height, 200 is height above ground foundation.
Support material takeoff and management
Support material take off and management shall be done as per project standard.