How to Perform the Water Supply System Design in Buildings with Plumber


With Plumber we have tried to facilitate the tasks that, even though they are not extremely complex, are often tedious and prone to errors when performing the analysis and the design of water supply systems in buildings.

In this tutorial we present the steps to create the network of nodes and pipes that the program uses for the design of the Water supply system that will supply a residential apartment.


Sections in this Tutorial:


1 Designing Schematic of the Water Supply System

The first step, before starting the Water supply system design with Plumber is to create a sketch that outlines the piping and fixtures in the system.

The definition of the path even though it is part of the Water Supply System design, mainly depends on the judgment of the designer, the architectural configuration of the Building and Plumbing Standards in the country of origin.

Here we have chosen to create the following scheme:

Designing-Schematic-of-the-Water-Supply-System

With this isometric view:

Isometric-View-of-the-Water-Supply-System

Regarding these figures, we highlight various aspects:

  • For the purposes of the program, a node is an element found where two pipes meet (as a Tee fitting, as in the case of nodes N1 and N3 in the cold water network and N2 for both networks). Node is also considered as the point where you have to supply a plumbing fixture in the network (remaining nodes in the scheme). It is not necessary to define a node in the direction changes of horizontal or vertical pipes, unless it is desired to change the diameter in the pipes.
  • The Riser node is the point of connection where it is supposed to be the vertical supply pipe (plumbing riser) of the Building or, if the water network is served by direct supply from the public system, it corresponds to the home downstream water meter point. For purposes of calculation and design, this is where you specify the supply pressure (calculation mode) or where the program will calculate the minimum pressure required to meet the operating pressure of the worst fixture of the water supply network.
  • Each node is assigned a unique name or label. In the example, it was given to nodes with fixtures, abbreviations of these, namely: “La” lavatory, “Lt” for laundry tray, etc.

Although the water supply system to design has a Hot Water network and a Cold Water network is only necessary in the case of fixtures receiving both supplies, specify a unique name for the node.

Similarly, in the points at which two networks overlaps, it is not necessary to generate two nodes as in the case of the nodes N2 and Htr (heater).

2 Specifying Fixtures Design Properties

The basis of the HUNTER’s method in the Water Supply System Design is the definition of the fixture units in each fixture. In Plumber, the available Fixtures already come with predefined values for this parameter, which can be modified by the user from the Fixtures Manager:

Fixtures-Manager-allows-to-assign-Hunter-method-fixture-units

In addition to the description and image columns of the fixture, there are the following columns:

Fixture Units (Total, Cold and Hot Water) Columns.

Corresponds to the Hunter’s method fixture units used in private and public Water Supply Systems. According to the option selected in the Occupancy box at the top, Plumber will use the respective group values.

Note that the values in the Total F.U. column will be used to calculate the probable flow for the pipes in the Plumbing Riser, if one exists in the project. Interior water supply system design will be made using the values of Columns Cold F.U. and Hot F.U. in the corresponding networks.

Minimum Pressure Column

Here you must specify the minimum operating pressure required for operation of each fixture.

Generally, plumbing standards fix a minimum value for all fixtures outlets, depending if they are tank or flush valve fixtures, but in the development of Plumber we have chosen to set different pressures according to the characteristics of each plumbing fixture. In any case, the user can modify these values.

Minimum Diameter Column

Depending on the characteristics of each fixture, the diameter of fixture supply pipe may vary and, therefore, it is in this column where the user must select the diameter for fixture supply pipe. This diameter is assumed to be equal for both the cold and hot water pipes.

In the following figure, it is highlighted, for the case of Kitchen Sink (Ks) in our example, fixture supply pipes:

Fixture-Supply-Pipes

One of the warnings that Plumber will show, in the event that the diameter of the water supply system pipe (blue and red lines in previous image) is less than the minimum diameter specified for the fixture supply pipe, is this:

Warning-message-in-plumbing-design

so the user can make the changes required to remedy the situation.

Geometric Height Column

For purposes of the Water Supply Systems calculations, Plumber will present two pressures at each node:

The pressure at the Node before feeding the fixture (If it has one installed) and the pressure at the outlet (where fixture will be connected), which must be greater than or equal to the specified value in Min. Pressure column in the Fixtures Manager.

In the figure, we relate the pressure values presented in the Node Table, with its position in the Water Supply System:

Pressures-in-water-supply-system-nodes

Pipe Length Column.

This column has added the ability not only to establish the length of the supply pipes to the fixture but it is also possible to specify the fittings that are installed on them (elbows, etc.). The specifications of these fixtures will not only calculate the equivalent length and the respective head losses in these pipe sections but will also be taken into account for the generation of the materials lists.

The lengths and accessories that are specified in this column (as well as the minimum diameter and the geometric height) will be considered similar for both supply lines to the fixture(cold and hot water).

To access Installed Fittings in Pipe Branches dialog, we will need to place the cursor on the cell for the fixture we want to modify and click in Equivalent Lengths button:

Installed-fittings-in-fixture-supply-pipes

The first row is reserved to specify the length of the pipe in the fixture supply riser. This row may not be removed from the table.

The following rows specify the type and amount of installed fittings in fixture supply riser. For our example, for the kitchen sink (Ks) fixture, we will have only a 90 ° elbow plus the straight length of pipe.

Installed-fittings-in-Kitchen-Sink

To add fittings to the Installed table, it must be selected in the table of Available Fittings and press the Add button:

Adding-fittings-to-pipes-branches

You can also double-click on the selected fitting to add it to the Installed list.

To eliminate or reduce the amount of an accessory installed, the process is similar:

Removing-fittings-from-pipes-branches

This procedure of specifying values in the fixtures table should be an activity that takes place only once (when we begin to use the program), usually because most data involved here are regulated by some plumbing standards.

Saving Changes in Plumber’s Configuration File

To keep the changes made to tables such as Fixtures, Fittings (Equivalent lengths) and diameters, making them available for new projects that we create, you must select the Options Settings menu → Save Configuration, from Start Menu:

Saving-configuration-for-future-projects

By using this option, will be stored in the application the options and Calculation Units specified in the Configuration tab.

So, when creating a new project for Water Supply System Design, tables and configurations will be the ones that adapt to the Standards and Design Criteria of the designer.

In case you wish to restore default options included in Plumber; you can use the Restore tables option (See figure above), whereby all changes that have been made are discarded. This option is only available for new projects.

3 Specifying parameters in Tables of Diameters and Equivalent Lengths of Fittings in the Project

Another aspect prior to the creation of networks in Plumber is to define the properties of the pipes to be used and, if we choose to use the Equivalent Length of fittings method for calculating head losses, their respective values must be specified in the Fittings Manager.

The top priority, because on it depend several factors, is to ensure that the nominal and internal diameters (the latter used for hydraulic calculations), available for the type of pipe used in the project, have been introduced, so that Plumber could make the proper selection in function of the diameters obtained in the calculation.

Regardless of the method for sizing pipes selected by the user in Plumber, the procedure is to obtain a calculated diameter and from that select the nominal diameter value closest above or below, as specified in the project diameters table.

Here we indicate the steps and characteristics of these two options, so we suggest you check it out.

4 Creating a Water Supply System in Plumber

One of the outstanding features of Plumber is the ability to contain several water supply systems with different characteristics on the same project. This makes it possible to perfom the riser design, assigning each of its nodes one or more of the water supply systems in the project, simulating the real situation in buildings with multiple levels.

Once created a New Project in Plumber, the first thing you should do is create a new water supply system:

From the Project tab of the program, click on the Create Water Network button:

Creating-a-new-water-supply-network

At right of the Create Water Network button also we will find the buttons to delete or to edit the actual water supply network properties discussed below.

Pressing the Create Water Network button will present the Water network Properties Editor, which we highlight its properties in the figure:

Water-supply-network-properties-editor

Thus, when assigning the properties and clicking OK to close the editor, new water network will be active in the Project List:

Creating-a-new-Water-supply-network-in plumber

In the Table of Nodes of the Active Water network, there is only one Node: the Riser Node. This is the default name assigned to what will be the source of the system, but in any case you can modify. This node cannot be removed from the project because is around it that will be determined the pressure required in the case of being in the design condition or, if in the case of calculation condition, where the supply pressure will be fixed by the user.

How to Change from the Water Supply System Design Condition to the Calculation Condition?

When you place the cursor in the riser Node row and press the Edit Node Button, you will see the Node Data dialog. In it, in addition to the text box for editing the name of the node, you will find an active checkbox with the text: Pressure Calculation.

When this checkbox is checked, we are telling the program to calculate the necessary pressure in the source node to meet the operating pressure of the most unfavorable fixture of the water supply system. This is the Design Condition.

If it is not selected, you will be presented with a text box in which you must enter the known pressure on that node. This is the Calculation Condition in Plumber:

Setting-Calculation-Condition-in-Plumber

5 Adding Nodes

The Project tab, Networks panel, contains the necessary buttons for the creation, elimination and edition of the components of the Project. At this level, only will be active the New Node and Edit Node buttons.

When pressing the New (Node) button, Node Data Editor will show up with two properties to assign:

Creating-a-new-node-for-water-supply-network

In Nodes Creation a default Label will be assigned, made up by the prefix that has been defined in the Creation of the Water Network (Water network Properties Editor) plus a correlative number.

In the example, after adding the Nodes according to our sketch, we would have the following Table of Nodes:

Nodes-in-water-supply-network

Eliminating and Editing Nodes

With nodes created in our project, it is possible to access to nodes editing options so, click on the corresponding row and press the Edit button or, by selecting the row (clicking on its header), to the Erase option. Both options in Networks panel, group Nodes, Project tab.

Editing-and-deleting-nodes-from-project

It should be had in account that, eliminating a Node from actual Water Supply System in the project, it will eliminate also pipes, if it is the case, connected to that node.

6 Creating Pipes of the Water Supply System

Plumber is configured to handle separately the Network of cold water from the hot water, although in the end, they are the same water supply network. It is possible to carry out the design of water networks that supply only cold water; therefore it is not mandatory to generate piping for hot water in the project.

The particularity of this separation is that the source of the cold water supply system, it is the Node that we define previously as Riser. And, in the case of the Hot Water supply system, the source will be the respective heater.

It is necessary that the user bears in mind the following aspects:

  • When there are hot water pipes in the project (lower right table in the Nodes and Pipes tab of the Plumber’s main window), there must be at least one node with a heater associated in the nodes table.
  • At least one of the pipes in the hot water network must have as upstream node a node with a water heater assigned (as it is the source of this system).
  • In the cold water network must also be a pipe whose Final node feed to the node with the associated water heater (to be able to supply the hot water network).
  • The program will calculate, in terms of the length and diameter assigned in the Fixtures Manager to the Water Heater, the head losses generated by the passage of water from the cold-water side of the heater to the entrance of hot water network.
Before accomplishing the calculation of the Water Supply System, Plumber will validate the introduced data to ensure that most of previous prerequisites are satisfied. If not it will present to the user the corresponding message and stop the calculation.

Addition of new pipes will be made through the buttons in the Networks panel of the Project tab:

Adding-pipes-to-the-project

When you select this option (New cold or hot water pipe), the Pipe Data dialog will be presented, in which it is necessary to establish which, from the previously created nodes in the project, will be the starting node and what the End node of this section of pipe.

It is important, at the time of the specification of the starting and ending nodes of each section of pipe, take into account that the initial node is upstream of the pipe (taking into account, of course, the direction of flow in the network) and the End Node which is downstream. This ensures that the results are that correspond to an open or branched network, which is the case for the majority of the Plumbing Water Supply Systems in buildings.

In this editor, we will find the option Diameter Calculation which, by default, is active (checked) in order to the diameter of the pipe section will be calculated automatically. If, for some reason or user’s criterion, it is necessary to specify the diameter, preventing that the program modifies it, this option must be deactivated (unchecked) to present the list of available nominal diameters in the project to select the desired diameter:

Setting-diameters-in-pipe-data-dialog

The most significant part in this editor (not only if you are in the option of calculating losses by equivalent length method, but also to establish the lists of materials of the project), it is the Lengths button, in which we can specify, as we saw previously, the fittings to install in this section of pipe:

Adding-pipes-and-setting-fittings-for-equivalent-length-calculation

Let’s notice of the previous figure that, by default, a fitting in each section of pipe is created: a Tee, assuming that most of the created branches will be supplying a Plumbing Fixture.

In relation to the above, it is important that the user, in those sections that correspond to terminal branches (as in the case of the section N3-Gh2 of our Water Supply System example) change this Tee to a 90° Elbow.

In addition, in Pipe Data dialog, you will find a check box with the ‘Supplies Fixtures With Flush Valve’ text, which by default is disabled. The purpose of this option is allowing the user to define what pipes supply fixtures with flush valve, in which case Plumber will determine the probable flow using the respective values from the method of HUNTER.

In our example there are not fixtures with flush valve and, therefore, we will hold the option deactivated for all the pipes.

At last, we will have the following tables of pipes:

Pipes-tables-Water-supply-system-example

Deleting and Editing Pipes

Similarly to the case of the nodes, we can edit lines, placing cursor in any cell in the respective row and pressing the Edit button.

To delete a pipe, taking into account that it will remove all pipes that are supplied by it, select the row (by clicking in its header) and click the Erase button:

Editing-and-deleting-pipes-from-water-supply-system

In the group of buttons associated with pipelines in each water supply system (cold or hot water), will find a button that allows us to directly access information of pipe lengths and fittings installed on it:

Editing-lengths-in-pipe-sections

7 Results of the Design of Water Supply System

At this level we have all the information that Plumber needs to carry out the calculation or the design of water supply system. Only need to make sure:

  • If you are designing, that is: If you want to determine the minimum pressure required in the water supply system source (Riser Node), the Pressure Calculation option in aforementioned node must be enabled (checked).
  • If you want to calculate the network, that is: know what real pressures at Nodes and Plumbing Fixtures are, you must specify a pressure in the Riser node, to which you must disable the option Pressure Calculation of this node.

Thus, there remains only to press the button Actual Water network at Calculate panel (Project tab) and, in case no problems with supplied data are detected, will be shown the following warning box:

Calculating-Water-supply-system

With which we will know that a solution has been achieved in the calculation.

Let’s look at the results:

Required Pressure at Water Supply System Source (Riser Node)

The pressures calculated both on the node and on the outlet of the supplied fixture, if applicable, will be presented in the table of nodes. We will see a warning symbol in the form of a flag, which tells us that design (i.e. the pressure calculated for the source node) has been made according to the minimum working pressure of the fixture attached to it (as assigned in Fixtures Manager):

Water-supply-network-design

Reviewing the rest of the outlet pressures in nodes with Plumbing Fixtures connected (both in the cold and hot water networks), you will see that it is satisfied that its value is greater than the specified value in the table of fixtures of the Water Supply Network (Fixtures Manager). In the following figure this comparison is done for Kitchen Sink (Ks) and shower (Sh):

Comparing-calculated-pressures-with-fixtures-minimum-operating-pressure

Diameters in Pipes Branches.

Once the calculation is finished, we will be able to see that a nominal diameter has been assigned to pipes (those in which was kept the option Diameter Calculation enabled), according to what’s specified in the Diameters Manager of the project.

In addition, pipes tables are updated to present the results of each of the parameters of hydraulic calculation. In our example, having kept all the pipes with the option Diameter Calculation enabled, we have the following output:

Results-Tables-of-pipes

It is noted that there is consistency with the decrease of the diameters as we move away from the Riser, with the only exception that shows up, for pipes N3-GH2 and Sh-Gh2, warning icons. In order to have details about these warnings, you must double click on them to view the message:

Warning-message-in-water-plumbing-design

In this case it is indicated us that the diameter of the fixture supply pipe for the garden hose is greater than the branch that feeds it from the water network, situation that contravenes the general recommendations of the hydraulic design.

To eliminate this warning we could set, editing referred pipes, the diameter in 19.05 mm, equal to the garden hose supply pipe. In the case of the N3-GH2 branch:

Modifying-pipe-diameter

Once modification was made we must press the button Calculate Actual Water Network again to update results.

When performing the aforementioned change we will see the adjustment in Water Supply Network pressures (and other parameters).

Thus, not presenting any additional error or warning message, we are ready to visualize the remaining results of the calculation.

Table of Fixture Units, Probable Flow and Diameters Calculation

This table, which is not editable directly, is is the one that shows up when we select the Diameters tab of the Plumber’s main window:

Table-of-Fixture-Units-Probable-Flow-and-Diameters-Calculation

Here we will see, among other parameters, the calculated diameter obtained by the program, the nominal diameter selected and the velocity of the flow for the inner diameter associated with that nominal diameter.

When the calculated flow velocity for the selected nominal diameter for any pipe is out of the range between 0.6 and 3 m/s, will be presented in this branch a warning icon to notify the user of this situation. This range, generally speaking, is set as ‘recommended’ in the design of water supply systems in buildings.

This is the case of the branches Gh2-N3 and Gh1-Sh, which have velocities below 0.60 m/s, due to the modification that we accomplish previously in the Tables of pipes.

Table of Calculation of Equivalent Lengths in Pipes

The third tab in the Plumber’s main window contains the calculation of the equivalent lengths in each section of pipe, presenting for each section the fitting, quantity, partial equivalent length and, finally, total equivalent length:

Equivalent-lengths-table

This table, just as the previous one, is not directly editable and presents the last two columns only if selected method for head losses calculation (Configuration tab→ Head Losses calculation panel) corresponds to the Equivalent Length.

In regards to hydraulic design that is all! With only a few clicks we have made the Water Supply System Design with Plumber.

Finally let’s look at the list of materials by selecting the Materials Lists button in Results tab→ Materials panel:

Materials-list-easily-created-in-Plumber

Here shows up, in separate groups, the Plumbing Fixtures, pipes and fittings for Cold water and the corresponding items to Hot Water system.

From the List of materials Table, as well as with other calculation and results tables of the design of water supply system with Plumber, it is possible to print, and also export to Microsoft® Excel, in the same way as we would with any other program for Windows®.