NORMAL MODE
Daily ventilation
Used to dilute vehicle pollutants and maintain acceptable air quality. Depending on parking geometry, it may be natural, mixed natural/mechanical, or fully mechanical.
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PROFESSIONAL LEARNING · PARKING VENTILATION
Car park smoke exhaust and ventilation overview
A compact engineering-learning page that explains the logic behind daily ventilation, smoke clearance, smoke zoning, ducted exhaust and jet-fan systems for car parks — without going into project-specific calculations.
WHAT THIS PAGE COVERS
01Daily ventilation vs. smoke exhaust
02Ducted exhaust and jet-fan concepts
03Design workflow and coordination checks
01
SYSTEM PURPOSE
Why car park ventilation is designed
Parking ventilation has two different design intentions: normal operation for pollution control, and emergency/smoke operation for smoke clearance, firefighter access and safer evacuation support.
EMERGENCY MODE
Smoke exhaust / smoke clearance
A smoke-exhaust system does not simply mean comfort ventilation. Its role is to remove smoke, reduce post-fire smoke concentration, and help emergency response conditions.
DESIGN INTENT
Firefighter access and escape routes
Smoke-control decisions should protect access routes, avoid pushing smoke toward exits and coordinate with stairs, ramps, shafts, sprinklers and fire alarm activation logic.
02
SYSTEM OPTIONS
Main smoke-exhaust strategies
The correct strategy depends on whether the parking is open or enclosed, the available openings, shaft positions, architectural constraints and fire-safety objectives.
NATURAL
Natural ventilation
Applicable where openings are sufficient and well distributed. It is mainly geometry-driven and should be checked early against code and architectural limitations.
OpeningsCross-flowEarly check
DUCTED
Ducted mechanical exhaust
Uses ducts, grilles, dampers and exhaust/supply shafts to distribute extraction points. It is easier to understand hydraulically, but needs careful coordination for space, pressure loss and fire-rated components.
DuctsDampersPressure loss
JET FAN
Impulse / jet-fan system
Uses impulse fans to push smoke and polluted air toward extraction points. It is layout-sensitive and requires attention to obstacles, ramp areas, slab drops, sprinkler interaction and activation sequence.
Jet fansObstaclesActivation logic
03
DESIGN WORKFLOW
A practical workflow for parking exhaust design
A good design begins with zoning and system intent before equipment selection. The goal is to connect architecture, fire alarm, sprinklers, shafts, fans and duct routing into one coordinated system.
STEP 01
Classify the parking and define the objective
Check whether the parking is open, enclosed or partially open. Then define whether the system is for daily ventilation, smoke clearance or a more performance-based smoke-control objective.
STEP 02
Divide the parking into smoke/ventilation zones
Zoning should respect fire strategy, escape routes, stair/elevator cores, shaft feasibility and similar zone sizes. Smoke zones should be coordinated with possible fire zones.
STEP 03
Estimate exhaust and make-up air
Use area, clear height and the selected air-change strategy to estimate exhaust airflow. Make-up air must be considered early so that extraction does not create poor flow paths or excessive door forces.
STEP 04
Locate shafts and main equipment
Avoid placing supply and exhaust in a way that causes short-circuiting. Keep exhaust discharge, ramps and escape routes in mind, especially where jet fans are used.
STEP 05
Develop duct or jet-fan layout
For ducted systems, distribute grilles and size ducts while checking pressure loss. For jet-fan systems, check fan direction, thrust coverage, slab drops and conflict with other life-safety systems.
STEP 06
Coordinate activation and emergency operation
Smoke exhaust must coordinate with detection, sprinkler flow switch, manual firefighter controls, power supply, damper status and fan start sequence.
04
DESIGN CHECKLIST
What must be checked before calling the design finished
- Daily ventilation and emergency smoke mode are not confused.
- Smoke/ventilation zones are logical and coordinated with fire strategy.
- Supply and exhaust locations avoid short-circuiting and poor airflow.
- Shaft dimensions and duct velocities are realistic for architecture.
- Jet fans do not create major conflicts with sprinklers, beams, slab drops or ramps.
- Fire-rated fans, ducts, dampers, cables and secondary power are considered where required.
- Fire alarm cause-and-effect logic is clear and coordinated.
- The final design is reviewed with architectural, electrical and fire protection drawings.
Important note
This page is an educational overview. Real projects must be designed according to the applicable local code, project fire strategy, AHJ requirements, product certification and coordinated engineering calculations.
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