When using SCBA, at hazardous materials incident, is important to include a _____________ into the estimated working time that is equal to approximately _____________ of the air cylinders working time.

• A. 1/2
• B. 1/3
• C. 1/4
• D. 2/3

Answer: (B)

Managing air supply in hazmat operations is about keeping a safety margin for a safe exit. The recommended approach is to reserve about one-third of the SCBA’s cylinder time as a safety buffer and base your estimated inside work time on the remaining two-thirds. This reserve accounts for delays, unexpected complications, or heavier than anticipated workload, ensuring you have enough air to retreat to safety.

For example, if a cylinder provides 60 minutes of air, you should plan roughly 40 minutes of actual inside work and keep about 20 minutes as the reserve. By including that buffer, you reduce the risk of running out of air before you can safely exit.