When it comes to the design of wastewater evacuation networks in buildings, the corresponding plumbing vent design issue is something that must be taken into account as an integral part of the project, given the importance it has in the proper operation of the system.
That is why in version 3 of DESAGÜES (DRAINS), we have included the possibility of creating individual vents networks, as well as soil stack vents.
So you’ll learn in this video the initial settings that you must carry out in the program before to start creating the plumbing vent system for each sanitary installation.
As you know, DESAGÜES requires that you specify the tables that you will find in your country sanitary codes and which define the maximum permissible fixture units for each waste pipe diameter of the sanitary network.
This is done from the Configuration tab, Diameters and Fixture Units button.
Here, the tables in the Sanitary, Pluvial, and Pluvial-Gutters tabs should already be known to you, from which the dimensioning of the horizontal, soil stacks and sanitary sewer networks is carried out.
But now you will see two new tabs.
Individual Vents’ Sizes and LengthTable
The first new tab is the one destined to Individual and branch vents dimensioning.
The Nominal diameters of the drain vent are shown, and which must, to keep consistency in the calculation, correspond to those you have created in the first tab.
Then you will see the column with the maximum fixture units vented through the individual vent pipe.
And finally, you will see the columns where, for each vent size, the maximum allowable development lengths are shown.
In this case, it is essential to note that the zero values indicate that this vent pipe diameter is not available, at least for the pipe diameter to ventilated fixture units combination.
Also, to change the name of the vent pipe diameters, you can double-click on the tables header to enter the new dimension in this dialog.
One factor that you can take into account in your projects is the length reduction factor requested below.
When the program is in the process of searching for the vent size, it will compare the actual length of the ventilation pipe with the length values in the table, multiplied by the reduction factor you have placed here.
As you suppose, it is a way to introduce a safety factor in your calculations, if you deem it necessary.
Finally, and since the individual vent pipe networks are horizontal, and are at a height greater than the overflow level of the highest sanitary fixture, we must specify here what is the corresponding height with respect to the floor’s level.
This value will be used for defining the respective lengths, as well as for isometrics views creation.
Vent Stacks’ Sizes and Lengths Table
Then, for the vent stacks dimensioning, we have the table on this tab.
In this case, you will see that the diameter and vented fixture units of the Soil Stack being ventilated are related to the maximum allowable development lengths for the respective stack vent size.
Analogously to the individual vents table, you can modify the name of these diameters by double-clicking on the corresponding heading.
You can also use here a reduction factor for the lengths entered in this table.
And this is all you need to set-up the program, at the level of calculation and your country’s sanitary codes parameters, and thus be able to start the design of the building’s plumbing vent systems.
Setting up the sanitary networks to receive Individual vents
Then, having already defined the vents sizing tables, we are going to see what changes are required in the horizontal drainage networks created in your projects to be able to “link” them, so to speak, to the respective vents networks.
First, and is what, in our opinion, is recommended, we will propose that each sanitary fixture in the drainage networks be ventilated individually.
This implies, as you know, that from each fixture or, better said, from the corresponding drain pipe, there must be a connection to one vent pipe.
We are going to explain it to you with some of the typical sewage networks we have in this project, which you will find in the program’s installation folder.
Note that here we have seven systems, with different configurations, since they are the ones in which we have tested this new feature of the program.
We will select network four that we see here in the drawing area.
As we will provide its sanitary fixtures with individual vents, the best thing we can do in this case is to propose a Branch Vent that runs along the line defined by this wall and reaches this point.
Here, this branch vent will be connected to the Vent Stack that, in turn, will be connected to the soil stack.
Finally, individual vent pipes required from the fixtures drain pipes will be connected to this branch vent.
We are going to sketch it up manually in the isometric view.
We propose to have a horizontal ventilation pipe, the branch vent, at this level, which, of course, is at a higher elevation than the overflow level of the Lavatory, which is the highest fixture of this sewage drainage network.
With one meter, entered in the configuration dialog at the beginning, it is enough in this case.
Then, to give individual vents to each sanitary fixture, we would have vertical pipes in this way.
So, going back to the plan view, we already know that from the construction’s point of view, new fittings are required at these points.
And that is why we must modify the sanitary network adding at these points new nodes that, since they do not have sanitary fixtures connected, will be considered as Tees, which, in turn, will serve as connection points for the vertical vent pipes.
Note, before we make any changes, the tables, and the values of this network in its original condition.
It handles a total of 14 fixture units.
Maximum drainage pipe diameter: 110 millimeters.
You will also see that in the materials list of there are not yet, and since they are not widely used fittings in horizontal drainage networks, sanitary tees.
Now, let’s make the referred modifications.
First, for the new nodes that I am going to create, I will modify for this installation the node’s prefix to lowercase “v” to highlight that they are sewer vents nodes.
Thus, I activate the node creation tool and click on each pipe section so that the program inserts a new one in each one.
I do the calculation and design again, so you can see that there is no change:
Fourteen fixture units with a maximum diameter of 110 mm.
Of course, now there are more nodes in this network.
But in the materials list you will see now that there are new fittings for the sanitary network:
The 110 and 50 mm tees required for the connection to what will be the vent pipe network of this drainage installation.
Thus, as we will see in the next video in this series, we are ready to create the waste vent network for network 4 of this DRAINS project.
See you there.