3M Scott Fire & Safety 3M Scott Sigma 2 SCBA Air Time Calculator
Select a model, choose your cylinder, enter pressure and breathing rate — duration is calculated instantly.
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ReadyThe 3M Scott Sigma 2 is Scott's marine and industrial SCBA, certified to EN 137 Type 2 and MED (Marine Equipment Directive). It is the lightest unit in the Scott lineup at 2.8 kg and is widely deployed on commercial vessels, in chemical plants, and in industrial emergency response teams.
MED certification: what it means and who needs it
The Marine Equipment Directive (MED / 96/98/EC) certification means the Sigma 2 is qualified for use on EU-flagged vessels where SOLAS safety requirements apply. Vessel operators, port authorities, and coast guard teams using SCBA for shipboard firefighting or confined space response in maritime environments need MED-certified equipment. The Sigma 2 satisfies both EN 137 Type 2 (structural firefighting capability) and MED (marine compliance) in a single unit.
Sigma 2 cylinder comparison: 200 bar steel vs 300 bar carbon
The Sigma 2 is available with two cylinder configurations. The 6.0L 200 bar steel cylinder is common on vessels that fitted out before higher-pressure cylinders became standard — it's heavier and provides less air: 6.0 × 155 (after 45 bar reserve) = 930 L ÷ 30 L/min = 31.0 min. The 6.8L 300 bar carbon provides significantly more: 6.8 × 245 = 1666 L ÷ 30 L/min = 55.5 min at light work. If operations require 30+ minutes of working time, upgrading to the 300 bar carbon option is strongly recommended.
Sigma 2 in industrial hazmat: scope and limitations
The Sigma 2 is EN 137 Type 2 certified and therefore qualified for structural firefighting as well as industrial use. Its simplicity — no HUD, no integrated PASS, lightweight design — makes it practical for industrial facilities that maintain SCBA for emergency egress and response teams. The absence of integrated PASS means standalone PASS devices are required to meet EN 137 requirements. Industrial teams using Sigma 2 in confined space rescue should note that the standard moderate-work RMV presets may underestimate consumption in physically demanding rescue scenarios.
Why the Sigma 2 uses lower RMV presets
The Sigma 2 RMV presets stop at moderate work (45 L/min) rather than extending to heavy or extreme. This reflects the Sigma 2's primary deployment contexts — marine emergency response, industrial hazmat, confined space — where tasks tend toward controlled, lower-intensity work compared to aggressive structural firefighting. If your team uses Sigma 2 in scenarios with high physical demand, manually enter a higher RMV (60–70 L/min) in the custom field to get a conservative planning estimate.
FAQ
3M Scott SCBA Air Time Calculator – ProPak-FX, Air-Pak X3 Pro & Sigma 2
3M Scott Fire & Safety operates two parallel SCBA lines: the ProPak series for EN 137 European markets and the Air-Pak series for NFPA North American markets. These are not interchangeable systems — cylinders, connectors, pressure ratings, and electronics differ between the two lines. The Sigma 2 is Scott's industrial marine model certified to EN 137 Type 2 and MED (Marine Equipment Directive), used in shipping and industrial hazmat. Select the exact model matching your unit for accurate cylinder and pressure options.
Scott ProPak-FX vs Air-Pak X3 Pro: the regulatory split
The Scott ProPak-FX is designed for EN 137 Type 2 markets (Europe, Middle East, export) and operates at 300 bar with 6.8L or 9.0L carbon fibre cylinders and the Tempest demand valve. The Air-Pak X3 Pro is the North American NFPA 1981 flagship, operating at 4500 psi (310 bar) or 5500 psi (379 bar) with Snap-Change cylinders and SEMS II electronics. Choosing the wrong model will give incorrect cylinder pressure and volume defaults.
Snap-Change cylinders: air time per entry vs total carried air
The Scott Air-Pak X3 Pro uses Snap-Change cylinder connections, designed for rapid field cylinder exchange without tools. For air time calculation, each cylinder provides independent air supply — the Snap-Change mechanism does not add capacity. In departments that carry spare cylinders on apparatus and exchange during rehab, effective air time per team member per operational period differs from any single-cylinder estimate. Factor cylinder exchange into your crew rotation planning.
SEMS II electronics: pressure monitoring and air time
The Air-Pak X3 Pro's SEMS II electronics include an electronic pressure gauge, HUD (heads-up display), and PASS device. The HUD displays cylinder pressure in psi to the wearer. For air management, the SEMS II alarm thresholds may not match your department's operational reserve policy. This calculator uses your entered reserve value — make sure it matches your SOP, not the SEMS II alarm point.
Scott Sigma 2 for marine and industrial users
The Sigma 2 is EN 137 Type 2 and MED (Marine Equipment Directive) certified, making it compliant for vessels under SOLAS safety management. It is also used in industrial hazmat response where EN 137 certifications apply. The Sigma 2 is available in 200 bar steel (6.0L) or 300 bar carbon (6.8L) configurations — the difference in air capacity is substantial. The 200 bar steel option is common on older vessels; the 300 bar carbon option provides significantly more usable air.
Vision 3 facepiece and mask seal: impact on air time
The ProPak-FX uses the Scott Vision 3 panoramic facepiece. In positive-pressure mode, a good mask seal prevents bypass flow and ensures full demand-valve efficiency. Poor mask seal — from incorrect sizing, facial hair, or improper fit — can cause air bypass and reduce effective duration. If your training data shows air time consistently shorter than estimates, mask seal and fit should be assessed before assuming higher RMV.
FAQ
Notes & Safety
This is an estimate based on the values you enter. Real-world air consumption changes with workload, stress, temperature, mask seal, leaks, and individual physiology. Always follow your SOPs and monitor your pressure gauge continuously.