| Applies To | |
| Product(s): | AutoPIPE |
| Version(s): | ALL; |
| Area: | Modeling |
| Date Logged & Current Version | Feb. 2022 12.07.00.346 |
Problem:
How to model to tank nozzle opposite one another on the same horizontal plane in AutoPIPE?
Solution:
Before any modeling contemplate all the different techniques currently available in AutoPIPE.
Options:
#1: Model as a Cross component
#2: Model as 2 back to back Tees component
#3: Model Tees using either method #1 or #2, but combine with Nozzle - Rigid elements.
Each method of modeling is technically correct therefore, each of these methods should be thoroughly understood before being used in a given model. One should thoroughly review the 3 different techniques used to model a Tee piping component before continuing below.
#1: Model as a Cross component
Modeling technique:
A. Model Vertical Tank / Vessel
B. Insert new segment starting to the left of the vertical tank / vessel.
C. Insert run, naming a node point on tank / vessel (ex. AM01), automatically turns node point into a tee.
D. Modify the tee, change Tee component from Tee to Cross.
E. Select 4th arrow of the tee and insert new pipe run (ex. HF01)
F. Manually calculate or have someone provide an SIF of the connection. Insert SIF at the intersection of the pipe centerline with the tank / vessel centerline
G. Done
Note: Consider modeling as a 2 point Tee component instead of a single Tee point component as instructed above.
#2: Model Cross as 2 back to back Tee components
A. Repeat Steps A to C from above procedure.
Note: in step C. above when creating the Tee configure the "Type of Tee" setting as needed to represent the nozzle connection (ex. welded, reinforced, etc..).
B. Next, insert new run ( ex. AM04) on vertical tank / vessel a very short distance (ex. 1-2 millimeters) above or below the newly created Tee node point (ex Am01)
C. Convert new node (EX. AM04) point into a Tee using AutoPIPE command Modify > Convert Point To > Tee
D. Again select branch tee arrow, use insert run command and insert new run (ex. HF01)
E Done
+
Note: Consider modeling as a 2 point Tee component instead of a single Tee point component as instructed above.
#3: Model Tees using either method #1 or #2, but combine with Nozzle and Rigid elements.
Reference
i. See AutoPIPE help section:
Help > Contents> Contents Tab> Modeling Approaches> Modeling Approaches> Vessel and Nozzle.
ii: On demand Video - YouTUBE Vessel Modeling - Method 1 / 2 - Presentation
iii. Modeling a 3 point tee.
A. Model pipe to surface of tank / vessel, (ex. GQ03)
B. Insert Nozzle element equal to tank / vessel thickness, and enter other Nozzle settings as needed.
C. Insert pipe to center of tank / vessel and apply Rigid Options Over Range (Insert > Properties > Rigid Options Over Range) to this pipe section.
D. Use Method #1 or #2 above to construct 2nd horizontal branch piping
E. Insert rigid pipe to inside of tank / vessel surface.
F. Insert Nozzle element equal to tank / vessel thickness.
Note: current node point should be located on the surface of the tank / vessel.
G. Continue piping as needed.
H. Done
Conclusion:
While all the methods above are technically correct for modeling a branch on a vessel, each one has their pros and cons with modeling and results. The user should select the modeling approach that best suits their situation of pipe size and vessel size.
#1: Model as a Cross component
Pros:
Easiest modeling approach, enable a single check box on the Tee component dialog to convert to a Cross component, select the 2nd branch, and continue modeling
Cons:
User must find a source to calculate a SIF outside of AutoPIPE and then manually input the value
Stresses are calculated at the center of the vertical vessel where the horizontal pipe is connected
#2: Model as 2 back to back Tee components
Pros:
Program will automatically calculate an SIF for each branch connection based on selected piping code
Cons:
The code SIF calculation does not take into consideration multiple branch connections in close proximity to one another. May want to analyze the connection in another application or hand calculations to get an overall SIF of the junction for both branches simultaneously
#3: Model Tees using either method #1 or #2, but combine with Nozzle and Rigid elements.
Pros:
Most accurate approximation for stresses at the nozzle connection locate on the vessel's surface
Takes credit for flexibility of vessel's wall
Cons:
Most time consuming modeling approach
User will need to select a specific Flexibility Method on the Nozzle element and enter details that may be difficult to answer
Note: See models here.