Time Air - online utility on ToolBox.
SCBA usable air usable = V·(P−P_alarm)/P_atm (V in L, P in MPa, P_atm=0.101325 MPa); consumption = breathing rate × tidal volume; service time t = usable/consumption; safe time = 0.75·t.
| Item | Formula / Note | Source / Standard |
|---|---|---|
| Cylinder capacity | 6.8 L @30 MPa ≈ 2040 L | GB/T 16556-2007 |
| Service time | t = VP/(40–60 L/min) | Work physiology |
| Low-air alarm | Alarm at 5.5 MPa (≈1/4) | GB/T 16556-2007 §5 |
| Turn-around time | Rule of thirds: exit ≤ entry | SCBA practice |
| Heavy work factor | 60–70 L/min heavy work | NIOSH studies |
| Temperature factor | P/T correction below 0 °C | Ideal gas law |
根据正压式空气呼吸器气瓶容积、压力与使用者劳动强度,估算可用使用时间与安全作业时间,为火场内攻与救援作业提供安全保障参考。