1. Breathing oxygen in diving. When diving is decompressed, the maximum safe depth of breathing oxygen in cabin resting state is 15 mm.

2. Air diving

A. The maximum depth of air diving is 60 M.

B. The maximum safe depth of air diving with self-propelled diving respirator is 40m.

C. The maximum safe depth of air-saturated diving is 15 mm.

3. Nitrogen-oxygen diving:

A. The maximum safe depth of nitrogen and oxygen diving is 50m.

B. The maximum safe depth of nitrogen and oxygen saturated diving is 36.5m.

C. When nitrogen and oxygen saturated diving, the maximum safe depth of air cycling diving is 70 M.

4. Helium-oxygen diving:

A. The maximum safe depth of diving with jet regenerative helium-oxygen heavy diving equipment is 120m.

B. The maximum depth of helium-oxygen saturated diving and itinerant diving is 300 m.

When the diving depth is more than 50m or the decompression time is more than 20min, the surface pressure chamber and its related equipment must be equipped. When using jet regenerative helium-oxygen heavy diving equipment, diving cages and related equipment must be equipped. When the diving depth is more than 150 m, hot water clothing and breathing gas heating equipment must be equipped.