Completing the Design
In this chapter some facilities for enhancing the basic HVAC design model are examined. The main features described are:
Replacement of implied ducting by catalogue straights.
Addition of stiffening flanges to ductwork items.
Item numbering of HVAC components.
This will be demonstrated using the duct work that was created in the previous worked examples, SUPPLY_LEVEL02-001.
Filling Ductwork Gaps – A Worked Example
During the creation of the main branch components were specified with specific functions. These include bends, side connection points, silencers and dampers. Most of the gaps between these components were left undefined and were consequently filled by implied ducting to complete the representation shown in the 3D view. To enable the design to be prefabricated, it is necessary to specify the fixed lengths of ductwork (ductwork straights) required between these components. This will also enable a full material take-off to be generated. The HVAC application is able to calculate the optimum combination of standard and non-standard straights needed to fill each gap and then create the corresponding components in the design database automatically.
Clear the 3D view.
Navigate to the main branch SUPPLY_LEVEL02-001 and add it to the 3D view.
To confirm the presence of gaps in the branch, Select Show Gaps from the Tools group located on the HVAC tab to display the Highlight Implied Ductwork (HVAC) form and click the Apply button.
For each gap in the named branch, the scrollable list area of the form shows the:
Location (the preceding component)
Calculated combination of straights to fill the gap.
All corresponding lengths of implied ducting are highlighted simultaneously in the graphical view.
The CE button on the form allows multiple branches to be checked.
If the user is presented with warning stating ‘This Gap will not be filled’ within the form, then the arrangement will need to be modified to allow for this.
Click the Cancel button to close the Highlight Implied Ductwork (HVAC) form. Select Fill with Straights from the Tools group located on the HVAC tab to display the Autofill with Straights (HVAC) form. Click the Apply button on the form.
A list of identified gaps is displayed and the specified straight lengths are created automatically to replace the implied ducting. The Model Explorer shows the new elements.
Exercise 5 – Completing the Design – Filling Ductwork Gaps
1. Using the worked example, show and subsequently fill all gaps with straights for all HVAC branches created during this training.
Adding Stiffening Flanges – A Worked Example
AVEVA E3D provides a utility for calculating the optimum number and positions of stiffening flanges needed to support ductwork items. The configuration of the flanges is tailored to suit the component geometry in each case. The user can then create and position such flanges automatically.
In the branch membership hierarchy, they are treated as sub-components of the straight.
Navigate to the straight shown below (STRT3) from the Circular main branch RETURN_LEVEL02-001 and make it the current element.
From the HVAC form, select Circular from the Categories list and then select Stiffening from the Available Types list to display the Stiffening form.
Based on the selected specification and the dimensions of the selected component, the number of required stiffeners are automatically calculated and displayed as shown. To create the stiffening flange, click the OK button on the form.
Exercise 6 - Completing the Design – Adding Stiffening Flanges
1. Using the worked example, check and add stiffening flanges to all HVAC branches created during this training.
Automatic Item Numbering and Naming – A Worked Example
The item numbering facility automatically allocates sequential item numbers to all HVAC components and gives each item a name of the format:
</PREFIX><number>, where /PREFIX is a user definable string and number is the sequential number. Sub-components, air deflectors, stiffening flanges, etc. are numbered as decimalised subsets of their owning components. Inline equipment items, silencers, fire dampers, etc. which are usually named, remain unchanged.
To auto number all HVAC items in the current design model, navigate to the owning HVAC Branch, SUPPLY_LEVEL02-001/02. Care should be taken if the selected owning element is the system element as opposed to the branch element. This is because the branch order below may not be in sequence. Again, this is important if the itemisation is to be consistent with the branch numbering, i.e., B1, B2, B3 etc.
Select Item Numbering from the Tools group located in the HVAC tab to display the HVAC Itemising form.
Set the Naming Prefix to
SUPP_LEVEL02-001/02/ITEM, leave the Start Number set to
1, and click the Apply button.
The HVAC Command Output form is displayed, listing all HVAC items and their allocated numbers.
Comparing the entries in this itemising list with those in the Model Explorer, it can be seen that each item (with the exception of any inline equipment components) has been named in the Model Explorer using the specified prefix /SUPP_LEVEL02-001/02/ITEM suffixed by the item number. i.e., the straights in the main branch, and their stiffening flange subcomponents, appear as follows:
Finishing Off Design Details
The design details for the ductwork straights can now be completed. This will entail:
Modifying joint types to suit the final design.
Inserting an access panel into the side of a length of ducting.
Modifying Joint Types – A Worked Example
When the lengths of implied ducting leading to the four fire dampers were replaced with straight components, the connecting joints will have been assumed to remain as default flanged joints. In fact, the fire dampers require raw edge joints, such that the ducting simply fits over the damper inlet and outlet.
The inlet joint for the damper is the leave joint for the straight that precedes it. To modify this joint, navigate to the preceding straight element STRT 4 of branch SUPPLY_LEVEL02-001.
Click the Leave Joint Choose button to display the Choose Joint (HVAC) form.
Select Raw Edge Joint, slip over 40mm (RE40) from the Choose Joint list and click the OK button.
Click the Apply button and then click the Cancel button on the Rectangular Straight form.
To modify the outlet joint between the damper and the following straight (the arrive joint of the straight), navigate to the straight.
From the HVAC form, click the Modify CE button to display the Modify Rectangular Straight form.
Click the Arrive Joint Previous button. The Arrive Joint field is set to RE40 by automatic reference to the previous component, namely the fire damper.
Click the Apply button and then click the Cancel button.
Exercise 7 - Completing the Design – Modifying Joint Types
1. Using the worked example, modify the joint types for the remaining Fire Dampers for BRAN SUPPLY_LEVEL02-001. All joint types to be updated to Raw Edge Joint slip over 40mm (RE40) joint.
Inserting an Access Panel – A Worked Example
The final component of the HVAC ducting network is an access panel in the straight before the final Fire Damper (FD4) of the main branch SUPPLY_LEVEL02-001. An access panel will be inserted; whose catalogue definition includes a predefined working volume, into the side of the aforementioned straight.
Navigate to the appropriate straight. From the HVAC form, select Rectangular from the Categories list and then select Access Panel from the Available Types list to display the Access Panel form.
Set the Select Size option to 300x200 and Dist from Leave to 200mm. Click the OK button.
The amount of detail shown in the 3D for different components is controlled by the current graphical representation settings. These can be checked by selecting Graphics from the Settings group on the VIEW tab to display the Graphics Settings form.
On the Representation tab select 50% from the Obstruction Visibility / Translucency dropdown menu. The obstruction volumes on all displayed components are now shown as a 50% translucency..