Pipe System Sizing

Used to compute and based on hydraulic pressure, velocity requirements perform piping sizing algorithms, and rebuild pipe system after resizing by optimizing route path pipe sections.

Accessed from:

Ribbon: Building Design > Analysis > HVAC > Pipe System Sizing

Opens the Pipe Sizing Section Summary dialog, where system sizing settings are done.

The dialog is used to load, set and compute pipe sizing parameters to construct an optimized pipe system by Equal Friction method. The dialog also allows to rebuild the resides pipe system and write to model, and generate various reports.

Setting	Description
Load System	Loads the active piuping system. When selected, and a valid route is loaded by selecting a source or first component in the route in the view, opens the Assign & Analyze Connection dialog, where flow types are mapped to the available connection ends. The Load System button turns , and remains animated until one of the mapped ends is selected to process. The route is then fully loaded with pipe section data populated in the summary table.
	When clicked the pointer highlights the pipe section row corresponding to the currently selected segment in the route geometry. Based on the Sectioning settings in Pipe Sizing - Settings, the pipes expanded in a given section are highlighted.
Number of Sections	Displays the number of sections comprised in the active pipe system.
Group By	The filtering and grouping list options are provided for listing the pipe components. Pipe Section — Displays the pipe components grouped in sections in ascending order. The collapse/expand arrow icons appears in 2nd column. The summary row above each section displays the sort criteria and the section number (Pipe Section:#), where # indicates the section number. The heading also displays the summary of section pressure loss. A single click in Pipe Section column heading will sort pipe sections. Piping Element — Displays the pipe components grouped in element in ascending order. The collapse/expand arrow icon appears in 2nd column applicable for entire element list. The summary row above the elements list displays only heading of the group by criteria (Piping Element:Pipe). A single click in PIping Element column heading will sort piping elements.
Pipe Sizing Table list	The pipe sizing table lists various columns that summarise pipe section numbering, fitting identifications, size and dimensions and physical properties associated with each fitting. Note: Refer to the section Working with Pipe System Sizing dialog for behaviour, functioning and use of various dialog fields. The following are the columns, arranged from left to right. Note: The unit mentioned in the parenthesis against applicable properties is in (unit: Imperial, Metric). Pipe Section — Displays the section number in a sequence for the sections in the pipe system. The letter suffixed with the Pipe Section number (s, e, r or f) indicates the flow types mapped during the load. Note that the pipe sections list appears in ascending order only for the supply flow type, as it's being a forward flow, whereas for the rest of 3 flow types, it is descending. Fitting No. — Displays the fitting number, labelled or numbered in a sequence for the fittings in the section. Piping Element — Displays the piping element labels, e.g. Pipe, Fittings or Fixture. When summary table is viewed using the Group by: Pipe Element, a single click in the column heading toggles the sort order once. Clicking in the cell or simply a mouse hover displays flyover listing the fitting components in the highlighted Fittings group (and Note, if any was added to the Pipe or Opening cell). These sub-fittings are mapped and assigned component types when populated in the Component Loss Coefficient Summary (CLC) table. Flow (unit: gpm, L/s) — Displays the value of air flow for the pipe segment in the section. The value is editable. Prior to calculating, usually the required airflow values are set at the openings like diffusers in the system. When routing, the Air Flow property associated components at outlet (Diffuser, Grilles etc.) can be set via the Parameters in the Place Component dialog. Pipe Inside Diameter (unit: inch, mm) — Displays the calculated size dimension of the pipe. The Diameter for a default round pipes. Double clicking in the field opens a drop-down list of options of alternate dimension, and can be selected that matches the actual size. Right-click and check the Lock option, if needs to keep one of the sides or both sides dimension or the diameter constant in computing. Velocity (unit: ft/s, m/s) — Displays the derived value of velocity of flow in the section. Click to edit the value if required or right-click and check the Lock option, if needs to be kept constant in computing. These values are kept within the moderate velocity for plumbing system and controlling the noise level. Velocity Head (unit: ft, kPa) — Displays the velocity pressure computed for the pipe section fittings for a given velocity. Pipe Length (unit: ft, m) — Displays the actual length of the pipe section. Summary of Coefficients — Lists the value of fitting loss coefficient for the fittings in the section row. Double clicking in the column heading or in the Fittings cell opens the Component Loss Coefficient Summary dialog. The CLC Summary dialog displays the loss coefficient values of pipe component fittings in each section and total loss coefficient value for the section are listed. The CLC summary table also lists Parameters used in the loss calculations. Correction Factor — Displays correction factor for the piping elements. For pipes and openings the correction factor is ideally set to 1, however can be overwritten to alter the pressure loss. Correction factors for fittings are maintained in CLC summary table. Pipe Pressure Drop (unit: in ft/100ft. kPa/m) — Displays pressure loss value. Applicable only for pipes. It can be altered to suit optimum pipe sizing. Right-click and check the Lock option, if needs to keep the pressure loss value for the pipe section be unchanged in the calculation. The friction resistance in flow accounts in pressure loss and the system is ideally aimed to control these values at a minimum throughout the flow paths. Total Pressure Drop (unit: in psi, kPa) — Displays the value of pressure loss in the total pipes and fittings in the section. For pipes, the default value is computed as the value of 1/100th Pipe length times the Pipe Pressure Loss. The mouse hover for pipes reads it as : "Total Pressure Drop = Pipe length / 100 * Pipe Pressure Drop * Correction Factor". For Fittings, it is based on Loss Coefficient value managed in CLC Summary table. Usually, it is read as: "Total Pressure Drop = Velocity Head * Summary of Coefficient". For terminals it is the Outlet Pressure property value set for the Parameters in the Place Component dialog. Note: For a more exact calculation using Pipe Sizing, all loss coefficients should be entered. This includes loss coefficient values for Opening type components (sprinklers, taps, etc.) that can be found in manufacturer's catalog data sheets. This value should be entered in the corresponding Datagroup property Outlet Pressure of the opening type component. Section Pressure Drop (unit: in psi, kPa) — Displays the value of pressure loss in each pipe element. The cumulative pressure loss for a pipe section is displayed as Summary of Section Pressure Loss when viewed Group By: Pipe Section. Details — For each row the Details column opens a pull up panel detailing the values of Viscosities, Reynolds Number for the selected pipe section/element and additionally the Limiting by Velocity/ Holding Constant Pressure drop pipe and fittings. In case of fixture details, the Fixture Units is displayed in place of limiting velocity or constant pressure. The Fixture Units is corresponding value of weighted unit of fixture on Hunter Curve of Flow Chart, taken internally in computing. This is read only data handy for a quick review. Clicking [x] closes the panel.
Calculate	Calculates the pipe sizing by internally computing the flow rate, velocity parameters against the physical dimension of pipe and pipe fittings lay in the system. Values altered in CLC Summary table and overrides, if any are reflected in the calculation. The critical route path report pops up indicating the path numbers of critical path and the value of pressure drop. The number in the left side indicates the path numbers and the numbers in the right side indicate section numbers and the resultant pressure drop. The pressure drop value is significant for paths having considerable resistance to flow. Clicking OK dismisses the pop up dialog and the critical path is highlighted in the geometry. The corresponding section rows in the table also highlighted in different color shade. Activated Calculate button turns , and remains animated until you click OK on the Critical Route Path pop up. When any velocity constraints is encountered, the message prompt alters `Pipe Velocity Limiting occurring`. Note: Ensure a non-zero air flow values are set to all Openings prior to calculate or generating any reports.
Rebuild	Enabled after Calculation. Rebuilds the active system for altered parameters set in the pipe system, including dimensions of pipe fittings in the pipe sections. This is done to achieve a desired Flow Loss Coefficient value. The geometry and properties associated with the pipe system are subjected to change in the rebuild. Write to Model — Alterations to pipe elements after the calculations are written back to respective pipe fittings in the loaded system. This will help to construct an ideal prototype of standard fittings of desired values that can be shared across designs in different projects. Activated Rebuild button turns , and remains animated until the rebuild (Write to Model) command is executing. Mismatch in the resized fittings, if any, may cause disconnects and you will be alerted with the View Disconnects dialog. You can locate and delete disconnected center lines and revise the route for reloading the system.
Settings	Opens Pipe Sizing - Settings dialog where design data, size criteria, and reporting options are set.
Reports	Provides options to generate pipe sizing reports of various needs: Check List — Generates a report that lists all piping elements in the system, their sizes and values of flow parameters. This type of report is helpful in process where computed values and intermediate result of pipe sizing in the form of report can be shared with expert authority for approval or advice. Sections: All — Generates the pipe sizing report showing the effect of critical path along the sections in the model. The list of path pressure drop is shown in descending order of route path. Critical Path — Generates the pipe sizing report specific to the critical section needing revaluation. This option adds a suggestive note in the footer of the report (e.g. suggested Minimum pressure required value) that hints in resolving the critical pressure loss. Reports are compiled and printed in a predefined style (as defined in Pipe Size Settings, Reporting Options). Generated reports can be viewed online, and using the report toolbar manipulated interactively or exported to a different format.

Key-in: MDL LOAD Bentley.Building.Mechanical.HydraulicDesign.dll