Designing mechanical ventilation installations

Product	InstalSystem 5
Type of article	DESIGNING LESSON
Source for translation	2025-11-10

Scope of lesson

This article presents the basic design path for the Ventilation systems for residential buildings based on off-the-shelf components.

Modules and program configuration

InstalSystem 5 with the module:

Mechanical ventilation for residential buildings.

Project file

The project file used in this lesson: Mechanical ventilation installation in residential building (example for the lesson).

Initial state

The project contains complete default data configured in the template file. The building structure has been elaborated on the basis of DWG layouts.

Steps to perform - Scenario I - сomplete design with air duct routing

Opening the project file

When creating a new design, select from the list the template that contains the default data for the ventilation system or,
Upload project file with existing building structure - minimum content is correct ordinates, slab thicknesses and manually created Rooms.

Editing the general project data

Fill in the default data in the General data window:

Project scope - determine project scope: Ventilation systems.
1. Project scope.
Catalogues – select and move necessary catalogues to the Catalogues in project: table. To speed up the selection, the filters can be used. For more information, see: Using catalogues and catalogues data in the project.
2. Catalogues.
General data editing:
- Storeys management:
  - Create the appropriate number of Storeys / sub-levels (by interpreting from IFC or manually);
  - Set storey data for Ventilation systems:
    - Choose the manner of Distribution of ventilation system:
      - Under upper slab,
      - On lower slab;
    - Improve the Default distance for ventilation elements.
      3. Storey data for Ventilation systems.
- (Optionally) Room data - for each / selected Room type, used in the project, set the values of:
  - Exhaust air volume flux (V̇_ex), Supplied air volume flux (V̇_su) or Min. vent. air change rate (n_min);
    4. Room data General data.
- Ventilation systems / Types and default data – append default types:
  - Default pipe types and insulation: Rigid duct;
  - Default pipe types and insulation: Flexible duct;
  - Default types: Other components:
    - Air handling unit / Recuperator,
    - Supply ventilation manifold / Exhaust ventilation manifold,
    - Wall air diffuser / Wall air extractor, Ceiling air diffuser / Ceiling air extractor, Floor air diffuser / Floor air extractor,
    - Duct silencer,
    - Air intake & exhaust;
  - Heat recovery efficiency: According to catalogue data, According to data for heat losses or User specified;
  - (Optionally) control and adjustment of the default value of v_max, m/s in the specified locations of the installation.
    5. Types and default data.
- Ventilation systems / Calculation options:
  - Select the Method of determining the amount of ventilation air;
  - (Optionally) enable the function Check the minimum amount of ventilation air per resident;
  - (Optionally) improve the value of θ_e - External temperature, design taken by the Air intake unit;
  - (Optionally) set Permissible excess/deficiency of static pressure before the supply/exhaust air vent (Δp_stat);
  - (Optionally) adjust the value of Required minimum static positive pressure behind the air diffuser;
  - (Optionally) adjust the value of Required minimum negative static pressure before the air extractor;
  - (Optionally) turn on the function Allow fan gear selection outside the recommended range.
    6. Calculation options.

Editing on the drawings

Editing the data

Set or modify the values of Exhaust air volume flux (V̇_ex), Supplied air volume flux (V̇_su) or Min. vent. air change rate (n_min) for each particular Room in the Data table in the Construction project scope.

Editing the installation

Carry out inserting and graphic editing operations using the AUTO and ORTO modes.

Select editing scope Ventilation.
Insert Ventilation elements:
- Recuperator,
- Manifold (supply) and Manifold (exhaust);
  8. Insert Recuperator and Manifold (supply).
Insert Ventilation terminals and indicate the Rotation angle, if necessary:
- Air intake,
- Air exhaust,
- Fresh air diffuser (grille, supply diffuser).,
- Return air inlet (grille, exhaust diffuser),
- Air intake & exhaust;
  9. Insert Ventilation terminals and indicate the Rotation angle.
Insert Vertical vent. duct;
Insert other elements of ventilation installation;
10. Insert other elements of ventilation installation.
Connect installation elements using Rigid duct or Flexible duct.

Editing the element data

In the case of necessity modify the Ventilation elements data in the Data table window, in particular:

Type of the Ventilation terminal;
Type of the Air diffuser / Air extractor;
V̇_su / V̇_ex for the Ventilation terminal;
Distance from ceiling (slab) / Elevation for the Ventilation elements;
Pipe type / Size for the Ventilation ducts;
Type of Insulation and Location for insulation purposes. Note: During Calculations the thickness of the Insulation is automatically determined taking into account the Location of the the duct in a heated or unheated space.

Verifying the correctness of the installation structure.

Verify the correctness of the connections of the installation components using the Check connections function (Shortcut: Shift + F2);
Verify the correctness of the installation structure using the 3D view;
Adjust the layout of the Ventilation ducts according to external factors, e.g. passages through walls, overlaps with other installations.

Running the calculations

Start the calculation of the Ventilation systems by clicking in the Calculations section of the toolbar;
Сheck messages the Diagnostics window;
In the case of necessity verify and adjust the installation:
- the error Fan does not provide the required air flow. V̇=%s [m³/h], V̇_min=%s [m³/h], V̇_max=%s [m³/h] is indicated:
  - choose other type of Air handling unit / Recuperator with appropriate parameters;
- the warning Fan pressure (%s) smaller than required in the installation (%s) is detected:
  - choose other type of Air handling unit / Recuperator with appropriate parameters;
- the warning Maximum air flow velocity exceeded (%s m/s > %s m/s) appears:
  - increase the Diameters / Sizes of the Ventilation ducts,
  - select other types of Air diffuser / Air extractor with the opportunity of connecting and placing additional air ducts,
  - add and connect more Air diffuser / Air extractor,
  - modify v_max, m/s;
- the warning Unbalanced ventilation air flow (ΣV̇_su <> ΣV̇_ex) is displayed:
  - correct the values of V̇_su and V̇_ex.

Verification of results

After calculations, the system layout should be verified visually by means of the 3D view;
If the calculations end with at least one error, the layout may be unreliable;
The data of each Ventilation element can be verified directly in the drawings by means of component labeling and hints containing tables with basic parameters.
11. Visual verification in the 3D view window.

Results tables

Use the tables presented in the Results window to verify the parameters of the installation:

Ventilation ducts;
12. Ventilation ducts.
Recuperators / ventilation units;
13. Recuperators / ventilation units.
Ventilation terminals;
14. Ventilation terminals.
Fresh air flow routes and Exhaust air flow routes - the tables show airflow routes, values of airflow and pressure losses for each particular installation element.
15. Results - ventilation.
Room list - Ventilation;
16. Room list - Ventilation.
Bill of materials - Ventilation systems;
17. Bill of materials - Ventilation systems.

Every item of the installation presented in the Results tables can be found in active windows by using icon.
For more information, see: Presentation of the calculations result.

Preparing drawings for export/printing

To have the results for Ventilation installation elements included in the printout of a drawing, appropriate labels must be inserted For more information, see: Preparation of drawings for export / printing.
Completed drawings can be printed and/or exported For more information, see: Export / print results and drawings.