A brief introduction to ductless parking ventilation system.

1. Mechanical Ventilation System
for Underground Car Parking

2. Ventilation System
 Natural Ventilation
Consist of Civil Ducts, OTS, Windows, Ramps etc with natural supply & exhaust
air.
 Mechanical Ventilation
Consist of civil/metal ducts, Axial Fans, Jet Fans etc with forced supply & exhaust
air.

3. Goals of Mechanical Ventilation System
 Remove Toxic Gases during normal
operation (CO & Nox).
 Circulate Fresh air
 Assist Fire Fighters in case of an
emergency (Control Smoke)

4.  Ducted Ventilation System
 Ductless Ventilation System
Types of Mechanical Ventilation System

5. Disadvantages - Ducted Ventilation System
 Increased Installation & maintenance Cost.
 Higher Operating cost as entire area is ventilated instead of focused area.
 Less ability to control the smoke.
 Aesthetically less pleasing.

6. Advantages - Ductless Ventilation System
 Lower Installation & maintenance Cost.
 Lower operating Cost.
 Reduced maintenance.
 Better smoke control hence enhanced safety.

7. Components - Ductless Ventilation System
 Axial Fans
 Jet Fans.
 Sensors.
 Control Panel.
 Communication Cabling.
 CFD Analysis

9. Purpose of Smoke Control
 Clear the smoke after fire has occurred.
 To create smoke free access point for firefighters.

10. Placement of Jet Fans
 A common size axial jet fan creates 25N thrust
 25N thrust could cover around 300 Sq.Mtr area.
 The distance between 2 jet fans should be 25Mtr.

11. Placement of Sensors
 Range of one sensor is around 500 Sq.mtr.
 The sensor should be installed above 1.8 mtr to avoid
vandalism

12. Need of CFD Analysis
 To optimize the number & placement
of fans.
 Simulate the space in normal & Fire
mode.
 Determine the visibility, smoke &
temperature throughout the space.

13. Contaminant Level (CO)
 NBC – 25ppm.
 ASHRAE---35ppm for 1 hour.
 Most International Standard use 35ppm as low level to balance
cost & safety.

14. Control Sequence
1. 0 ppm – Only supply & Exhaust Fan ON (If required to maintain
minimum ACPH)
2. CO>15ppm – Supply & Exhaust Fan ON.
3. 15<CO<35ppm – Select Jet Fans ON.
4. CO>35ppm --- All Jet Fans ON.
5. CO>100ppm --- All Fans on High Speed (Fire Mode)

15. Product Requirement
 High Temperature fans & cabling required.
 In India fire rating is 250Deg.Celc. to 300 deg.cel..

16. Required Air Changes per hour (ACPH)
 NBC 2005 --- 9 to 12 ACPH under normal operation, 30ACPH in
fire mode.
 MMRDA Standard---15ACPH in normal mode, 30ACPH in fire
mode.
 NBC 2016 --- 6ACPH under normal operation, 12ACPH in fire
mode.

17. BOQs
 As per NBC 2005 --- 12 ACPH & 18 ACPH are Considered.
 As per NBC 2016 --- 6 ACPH & 12 ACPH are Considered.

18. THANK YOU