The BW CG-Q34-4 is a 34-liter four-gas ("quad gas") calibration cylinder containing 2.5% methane (CH4), 18.0% oxygen (O2), 25 ppm hydrogen sulfide (H2S), and 100 ppm carbon monoxide (CO), with nitrogen as the balance gas. The 2.5% methane equals 50% LEL. Each component is certified to ±5%, and the cylinder holds 34 liters (1.2 cu ft) at about 500 psi.

The BW CG-Q34-4 is used to bump test and calibrate BW/Honeywell (Honeywell Analytics) portable four-gas detectors that monitor combustible gas (LEL/methane), oxygen, hydrogen sulfide, and carbon monoxide — for example the BW GasAlertMax XT II, GasAlert MicroClip XL, and BW Clip4. Applying the known gas confirms each sensor responds correctly and that alarms trigger at the right levels. Always confirm the exact cal-gas mixture your detector requires in its manual before ordering.

Because 2.5% methane by volume equals 50% of methane's Lower Explosive Limit (LEL). Methane's LEL is 5.0% by volume, so 100% LEL = 5.0% and 50% LEL = 2.5%. Calibrating a combustible (LEL) sensor at 50% LEL is a standard midpoint that verifies the sensor reads accurately and that its combustible-gas alarm activates well before a truly explosive atmosphere is reached.

The BW CG-Q34-4 uses 18.0% O2 on purpose. Normal air is about 20.9% oxygen, so a reduced 18% level lets the calibration confirm that the detector's oxygen sensor reads accurately in an oxygen-deficient atmosphere and that its low-O2 alarm (typically set at 19.5%) activates — the exact hazard an O2 sensor exists to catch. Testing only at 20.9% would not prove the sensor can detect a dangerous drop.

Yes. The same BW CG-Q34-4 four-gas mixture works for both a bump test (a quick check that each sensor responds and alarms) and a full span calibration (adjusting the detector's readings to the known gas values). A bump test uses very little gas and is recommended before each day's use; a full calibration uses more and is done on a set interval. Both apply the gas through a compatible flow regulator.

The BW CG-Q34-4 requires a compatible flow regulator that threads onto the cylinder to deliver gas to the detector. BW/Honeywell offers both demand-flow regulators (for pumped instruments that draw gas on demand) and constant-flow regulators; the cylinder label references a 0.25 lpm regulator delivering roughly a 2-minute test/calibration per use. The regulator and calibration cap/tubing are separate accessories, not included with the gas cylinder.

The BW CG-Q34-4 has a 24-month shelf life, with the exact expiration date printed on the cylinder — always check it before use, since expired cal gas can drift out of spec. In service, a 34-liter cylinder supplies many short bump tests and calibrations; the label notes roughly 2 minutes of gas per test at a 0.25 lpm flow rate, so actual number of uses depends on your regulator and detector.

The BW CG-Q34-4 is a compact 34-liter (1.2 cu ft) cylinder pressurized to about 500 psi, measuring roughly 11 in tall by 3 in in diameter and weighing about 1.05 lb. Its small size makes it easy to carry in a field calibration kit or store in a gas-detection service bench while still holding enough gas for numerous bump tests and calibrations.

The BW CG-Q34-4 ships with free shipping from Industrial Safety Products. However, like other compressed-gas cylinders it is not eligible for returns or exchanges, so confirm you are ordering the correct four-gas mixture (2.5% CH4 / 18.0% O2 / 25 ppm H2S / 100 ppm CO) for your BW/Honeywell detector before purchasing.

Choose based on how much gas you use. The BW CG-Q34-4 holds 34 liters, while Honeywell offers the same style of cal gas in volumes up to 103 liters. The 34L size is compact and lighter for occasional bump testing or a small fleet of detectors, while larger cylinders mean fewer changeouts for high-frequency calibration programs. All use the same quad-gas concept; match the mixture (CH4/O2/H2S/CO) and concentrations to your detector.

For BW/Honeywell detectors, yes. The CG-Q34-4 is formulated to BW's standard four-gas specification (2.5% CH4 / 18.0% O2 / 25 ppm H2S / 100 ppm CO), with each component certified to ±5%, so you get a documented, in-spec mixture the manufacturer validates for its instruments. Using the manufacturer-matched cal gas removes guesswork about whether an off-spec mixture could bias your sensor calibration — which matters when the detector is protecting a worker's life in a confined space.