[Plumbing Expert] How to choose between siphonic rainwater drainage and gravity rainwater drainage?

[Plumbing Expert] How to choose between siphonic rainwater drainage and gravity rainwater drainage?

Siphonic rainwater systems are suitable for high-end buildings with large roof areas and high drainage volumes; they use small pipe diameters and require minimal buried piping, but need professional design. Gravity rainwater systems are simple and reliable, with low maintenance costs. For five-star hotels, siphonic systems are recommended.