The schematic mainline layout mentioned earlier in this section was useful in locating the valves and positioning the schematic mainline piping layout to them and the quick couplers.
When you select the Draw Mainline Pipe function, the lateral lines will be turned off to better visualize where the mainline is going. When you are finished with this function, the lateral lines will automatically turn back on. As you will not see the lateral lines when you pipe the mainline, the schematic mainline layout is important to help the Designer avoid drawing the mainline directly over a lateral line or other similar situation.
Imagine the Draw Mainline Pipe function as placing actual pipe in the field.
When you select the Draw Mainline Pipe function, the command line will read:
This indicates you may:
F Remember: The AutoCAD Ortho function, either F8 or the Ortho Button, can be activated and the mainline will be drawn in a ortho relationship to the crosshairs. This can be freely toggled on and off while drawing the mainline.
Select the Draw Mainline Pipe function and start at the water meter (or other P.O.C. if the situation is non-metered), and connect the meter to the backflow device. You will notice that when an item is selected, it will be highlighted as heads are in lateral piping. This, as with lateral piping, allows the End User to know that an item is selected and piped to.
It would be fine to draw the mainline to the valves and quick couplers, then add the connection to the water meter or P.O.C. at a later date. This would be the case if your were not sure where the water meter will actually be located, but need to continue with the Irrigation Plan at the moment.
Now draw the mainline in a similar location to the schematic mainline layout. The schematic layout is for general direction only, and you don’t necessarily have to follow it carefully, but it is there for a reason. It is often useful to keep the Ortho function on, with F8 or the Ortho Button.
Draw the mainline and connect to valves and quick couplers as required. While it is best not to draw a mainline directly over and parallel to a lateral pipe, it is OK to draw over heads and cross where lateral pipe will be. You will be given the opportunity to clean up mainline conflicts after you have drawn it. You can use the Pipe Arc function on the mainline as well as on the lateral lines.
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Before sizing the mainline, you will want to verify that all of the valves and quick couplers (or hose bibs) have been piped to. The Verify Mainline function verifies that all valves and quick couplers are piped.
Verify Mainline will first check to confirm that all valves have had their lateral lines sized. If any have not, the valves will be highlighted, and a dialog box will notify you that the circled valves need their lateral lines sized.
If any valves or quick couplers are not connected to the mainline when you select the Verify Mainline function, a dialog box will appear to inform you that unconnected items are circled in Yellow.
If all of the valves and quick couplers are properly connected to the mainline, and at least one valve is called out, the dialog box will instead indicate which valves have yet to be called out. If all valves are connected to a water source and called out, it will simply indicate that all valves are correctly labeled and connected.
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Select the Size Mainline function and click on the water meter, or the P.O.C. if that applies.
A dialog box will appear to see if you are designing for a Single Valve Operating at a Time, or Multiple Valves Operating at a Time.
In this example, select Single Valve Operating at a Time, and the mainline will be sized and a Critical Analysis Report will be displayed.
Note that the Flow Velocity used in sizing the Mainline is indicated on the dialog box, allowing easy access to changing this value. It is also replicated on the Pipe Data dialog box. It is replicated here, as when a mainline cannot be sized, due to having pressure requirements greater than the P.O.C. can provide, often simply reducing the velocity of the flow can result in lower pressure needs. Also, for a looped mainline, particularly if it is a large system over long distances, a flow velocity of three or four fps would be more appropriate than five or more.
This report will list all valves in the drawing, with columns for the types of heads connected to them, their size, GPM, PSI, and Precipitation Rate.
After selecting the function, you will be prompted with the following dialog box:
You can send the schedule into the drawing, or to a spreadsheet.
An example of the generated schedule looks like the following:
This report will determine if there is adequate flow and pressure for the system as designed. Various factors will be listed that effect the mainline for the P.O.C. selected. This includes:
When the mainline is sized, the mainline pipes are color coded for the different sizes, but the sizes are not called out. This is purposely done to allow the Designer to add the mainline sizes manually where he/she thinks it is best to communicate the design.
Use the Pipe Label function to label the mainline at transition points and other locations as desired. Use the Pipe Label Cleanup function to move the labels as required to the best locations. The font used for the mainline size is slightly larger than the font used for lateral line size for clarity.
The mainline will be plotted as a heavy dashed line. As the mainline was laid out in the drawing, it crossed over heads, lateral lines, lateral size callouts, site objects, etc. Now is the time to clean up any graphic conflicts.
Select the Mainline Break function and break the mainline wherever it interferes with other piping or heads. This is similar in control and effect to the AutoCAD Break command for breaking lines.
F Remember: You should always break the mainline with the Land F/X Mainline Break function and not the AutoCAD Break function. The Land F/X Mainline Break function appears to break the line, but in actuality, it inserts an invisible pipe length between the break points. Using the Land F/X Mainline Break function allows you to change and re-size the mainline at a latter date, and does not disrupt the connections to the valves and quick couplers.
