What are the general principles for the design of very early fire warning system?

1. The standard sampling pipe is a flame-retardant PVC pipe with an outer diameter of 25mm installed in the protected area.

2. In order to ensure that the air flow through the air sampling system is smooth, the air pressure discharged by the suction pump shall be equal to or slightly lower than the air pressure in the detected area. The protection range of a detector is 2000 square meters (H = 3-5 meters), and the limit is 2500 square meters. In places with higher protection level, the protection range shall be reduced to 500-1000 square meters (or 1500 cubic meters).

3. The sampling hole on the sampling pipe is Φ 2.5 - Φ 4.0mm, and the distance between the sampling holes is 1-4m. Generally, each sampling pipe is divided into three sections. If the single pipe is 70m long, the sampling hole in the first 20m is Φ 2.5mm. The middle 30m sampling hole is Φ 3.00mm, and the latter 20m sampling hole is Φ 3.5mm. The sampling holes are enlarged in turn, and the end plug is 4 Φ 4 holes. Each sampling hole is labeled with an indication label.

4. The right angle bend on the sampling pipe shall avoid small radian as far as possible, and manual bending with radius greater than or equal to 20cm can be adopted, so the sampling pipe shall be flame-retardant cold bend.

5. The total length of sampling pipeline is less than 200m, and the limit is 250m (4 × 50m, 3 × 70m, 2 × 100m), while the number of sampling holes on each sampling pipeline is not more than 25. When only one pipeline is used, the length is not more than 100m.

6. Each pipe has less than 10 right angle bends.

7. In practical application, the length of each pipeline should be as close as possible, so that the air flow in the air sampling system can be easily balanced.

8. ABS pipe or other metal pipe can also be used if the environment requires the sampling pipe to bear great bearing capacity or be exposed to strong light and extreme heat for a long time.

10. The spacing of each sampling hole (i.e. protection radius) shall not be more than 8m, and the distance between pipes shall not be more than 8m, and shall not be less than 1m.