What are the requirements for the location of hotel fresh air intakes? How can the intake of polluted air be avoided?
I am an HVAC expert. The location of hotel fresh air intakes is a key part of HVAC system design and directly affects indoor air quality and guest health. If a fresh air intake is improperly located and draws in vehicle exhaust, kitchen fumes, or odors from a refuse station, it will not only violate code requirements but also trigger a large number of guest complaints and O&M problems. Therefore, strict control must be exercised at three levels: codes, engineering practice, and site conditions.
**I. Code Requirements and Key Clauses**
According to Clause 6.3.1 of the Code for Design of Heating Ventilation and Air Conditioning of Civil Buildings (GB50736-2012), the location of fresh air intakes shall meet the following requirements:
- It shall be located in an area with relatively clean outdoor air and on the windward side of exhaust outlets.
- The bottom of the fresh air intake should preferably be no less than 2 m above outdoor ground level; when located in a landscaped area, preferably no less than 1 m.
- Intake of pollutants discharged from restaurants, kitchens, boiler rooms, etc. shall be avoided.
In addition, Clause 6.3.2 of the Code for Design of Heating Ventilation and Air Conditioning of Industrial Buildings (GB50019-2015) emphasizes that the horizontal distance between a fresh air intake and an exhaust outlet shall not be less than 20 m; when the horizontal distance is insufficient, the fresh air intake shall be lower than the exhaust outlet, and the vertical distance shall not be less than 6 m. For hotel projects, the Code for Design of Hotel Buildings (JGJ62-2014) should also be referenced; the fresh air system should be provided independently to avoid crossing with the exhaust system.
**II. Specific Measures to Avoid Intake of Polluted Air**
1. **Select a location away from pollution sources**: Fresh air intakes should avoid parking garage entrances and exits, refuse rooms, kitchen exhaust outlets, cooling towers, boiler room chimneys, etc. In engineering practice, I once handled a case: the fresh air intake of a star-rated hotel was located on the podium platform, adjacent to the kitchen exhaust outlet, causing the fresh air to contain cooking-oil odors. After modification, the fresh air intake was moved to the north side of the roof and an activated carbon filter section was added, and only then was the problem resolved.
2. **Location height and direction**: The bottom of the fresh air intake should be at least 2 m above ground to prevent ground dust or vehicle exhaust. The intake orientation should avoid facing downstream pollution sources in the prevailing wind direction. For example, in coastal areas, salt-spray corrosion brought by sea breezes must be considered; in northern regions, snow accumulation must be avoided.
3. **Provide rain louvers and protective screens**: Fresh air intakes must be equipped with rain louvers to prevent rainwater intrusion, and stainless steel protective screens (mesh size ≤10 mm) should be added to prevent birds or debris from entering. According to Clause 6.3.2 of the Code for Acceptance of Construction Quality of Ventilation and Air Conditioning Works (GB50243-2016), the rain louvers of fresh air intakes should be easy to clean and replace.
4. **Adopt monitoring and interlock control**: In areas with high pollution risk (such as near urban roads), it is recommended to install PM2.5, CO, and NO2 sensors at the fresh air inlet, and automatically close the fresh air damper or switch to internal circulation mode when concentrations exceed limits. In a hotel renovation project, I adopted this intelligent control strategy, which effectively prevented exhaust intrusion during morning and evening peak hours.
**III. Engineering Case**
A five-star hotel is located at the intersection of major urban roads. The original fresh air intake was located on the third-floor podium platform, only 1.5 m above ground, and directly facing the parking lot exit. After operation, frequent guest complaints were received that "the room smells of gasoline." On-site measurement showed that the CO concentration at the fresh air inlet reached 15 ppm (normally should be <9 ppm). We took the following corrective measures:
- Moved the fresh air intake to the main building roof (30 m above ground), away from pollution sources.
- Added a medium-efficiency filter section (F7 grade) in the fresh air shaft.
- Installed an air quality monitor to interlock with variable-frequency operation of the fresh air handling unit.
After the modification, the indoor CO concentration dropped below 2 ppm, and the complaints disappeared.
**Summary**: The core principles for locating hotel fresh air intakes are "avoid pollution, install high, windward, independent," and only by combining monitoring and filtration measures can fresh air quality be ensured. The above are reference opinions. The actual project conditions still need to be further comprehensively evaluated and implemented in combination with specific operating conditions, site conditions, and other factors.