Gas detection solution for fresh air system

2023-04-03 17:08:27

At present, due to the serious air pollution and frequent haze, everyone has bought air purifiers. However, the air purifier can not improve the indoor oxygen deficiency, so the fresh air system is in use. The fresh air system can establish an air transmission channel for indoor and outdoor without opening doors and windows, and the filter device can intercept outdoor pollutants.

The fresh air system can solve the problem of indoor hypoxia, but the 24-hour fresh air ventilation not only brings about the problem of high energy consumption, but also the excessive loss of fresh air equipment and filtration devices, which is very uneconomical. Therefore, the fresh air system should monitor the indoor oxygen and guide the ventilation time of the system. When the oxygen concentration is not up to the standard, the ventilation should be carried out, and when the concentration is up to the standard, it should be put into standby operation.

Fresh air system is widely used in people’s life at present. Using fresh air system can effectively improve the air quality and other problems in people’s life. But how to detect the fresh air system is a headache for people, so how to detect the fresh air system is correct? We will offer you a detailed explanation.

Detect the room

The representative rooms in charge of the ventilation system to be tested (such as independent offices, meeting rooms, open spaces, etc. in public buildings; living rooms, bedrooms, etc. in residential buildings) shall be sampled for inspection. The number of samples shall not be less than 30% of the total number of rooms, and shall not be less than 3. When the total number of rooms is less than 3, all rooms shall be tested. Interpretation: For example, we have 100 rooms here, and the room for sampling test is no less than 30 rooms, and less than three rooms, so we should test the purification efficiency of the fresh air system in each room.

Detection points

The number of test points in each test room shall be determined according to its area. See When there are two or more detection points in the room, the diagonal, diagonal and quincunx shall be used to evenly distribute the points, and the average value of the detection results of each point shall be taken as the detection value of the room. For example, if your house is 80 square meters, you should find two locations to test (for example, the purification efficiency of the master bedroom and the purification efficiency of the hall), not just one point.

Detection times

Each test point shall be sampled repeatedly for 3 times, each time for 1 min, and the average value of the three times shall be taken as the concentration value of the point. For the case of large deviation of the three sampling values (exceeding the range of ± 20% of the average value), the sampling times shall be increased to reduce the sampling error. Taking the average value as the collection basis, it is necessary to collect more than three times at the same place to prevent the error caused by the parameters.

Sampling location

The on-site detection point of indoor PM2.5 pollutant concentration shall be no less than 0.5m from the inner wall and 0.8m-0.15m from the ground. The detection points shall be evenly distributed, avoiding the opening of air ducts and vents.

The fresh air system mainly detects the important indicators of air quality voc, CO2, oxygen, formaldehyde and PM2.5. The sensor is the core device of gas detection. We are making reference to the parameters and performance characteristics of the oxygen sensor in the gas as follows:





Detection principle

Electrochemical Two electrodes

Detection gas


Detection range


Maximum load concentration


output signal

100±20㎂ in air

Zero drift




Response time


Bias voltage


Load resistance


Load resistance


Load resistance

15%RH to 90%RH(no condensation)


<±2% output signal

  Long-term stability

<5% signal/year


Linearity,regression coefficient R²=0.999

Work pressure

90 to 110 kPa

Shelf life

12 months after delivery

Service life

2 years

Home WhatsApp Mail Inquiry