SCBA Cylinder Work Time
Time to low-air alarm and to empty from rated scf, current pressure, alarm pressure, and consumption rate. NFPA 1981 governs cylinder ratings; exit at the alarm, not at empty.
Formula and source
available_scf_to_alarm = (P_start - P_alarm) / P_rated * V_rated. time_to_alarm_min = available_scf / consumption_scfm. Time-to-empty is a math aid only; exit at the low-air alarm.
NFPA 1981-2019; NIOSH 42 CFR 84.
Audience
This tile is built for fire-ground and the adjacent professions in the Fire-Ground Engineering group. The interactive calculator runs entirely in your browser. No account, no fee, no advertising, no tracking.
Related tools
Posture
Rough Logic answers the math question the working professional asks on the job. The site is a calm, fast, ad-free, account-free, ever-free reference. It does not interpret code. It does not replace the licensed professional. It does not store your inputs. The Authority Having Jurisdiction governs all installations and inspections.