Trigas USA 4-gas calibration gas is the multi-gas mix used to bump test and calibrate confined-space monitors that read carbon monoxide (CO), hydrogen sulfide (H2S), combustible gas (LEL) and oxygen (O2) in one cylinder. Every quad mix is blended in a nitrogen balance, NIST traceable with a Certificate of Analysis (typically ±5% tolerance and a 24-month shelf life — see each product page), and filled in a disposable aluminum cylinder with the standard C-10 connection.

The standard 4-gas blends

Two blends cover most instruments on the market. 50 ppm CO / 25 ppm H2S / 2.5% CH4 (50% LEL) / 18% O2 — 34 L ($120) or 58 L ($160). 100 ppm CO / 25 ppm H2S / 2.5% CH4 (50% LEL) / 18% O2 — 34 L ($130), the direct replacement for BW/Honeywell CG-Q34-4, or 58 L ($150), replacing CG-Q58-4. Pentane-based LEL and propane-based LEL versions of the same mixes are also stocked for instruments calibrated on pentane or propane.

OEM-specific quad mixes

Each monitor manufacturer specifies its own blend, and Trigas stocks them with the OEM part number cross-referenced on the product page: MSA ALTAIR monitors — 60 ppm CO / 20 ppm H2S / 29% LEL pentane / 15% O2 (34 L, MSA 10048280; 58 L, MSA 10045035); Industrial Scientific Ventis and MX6 monitors (1810-2187, 1810-2242, 1810-3937); RKI (81-0154RK); RAE Systems (600-0050-001); Dräger (4594943); Biosystems, Crowcon, GfG, Lumidor, Calgaz, Portagas and Norlab equivalents. Not sure which one your monitor takes? Paste the OEM part number into the part number finder.

Sizes, bump tests and how long a cylinder lasts

34 L cylinders start at $100 and are the right size for a single monitor or a small crew; 58 L (from $136) and 116 L (from $224) suit fleets, docking stations and daily bump testing. Beyond 4-gas, the same collection includes 2- and 3-gas subsets (for example 25 ppm H2S / 50% LEL CH4) and 5- and 6-gas mixes that add CO2, SO2 or NO2 for instruments with extra sensors.

Regulator for 4-gas calibration gas

Because quad mixes carry a reactive component (H2S, and in some blends SO2 or NO2), pair them with a stainless steel regulator: a fixed flow model preset to your monitor's flow rate (commonly 0.5 LPM) for diffusion instruments, or a demand flow regulator for pump-equipped monitors and docking stations.

Frequently asked questions

Which 4-gas calibration gas do I need? The blend printed in your monitor's manual or on the calibration screen. If the manual only gives the OEM part number, search it on the part number finder and the matching Trigas cylinder appears.

Bump test or calibration — do I need different gas? No. The same cylinder is used for both: a bump test only checks that every sensor responds and alarms; a calibration adjusts the reading to the certified concentration.

Can I use 4-gas mix on a single-gas H2S or CO monitor? Yes, if the ppm of that component matches the instrument's calibration value; the other components are simply ignored by the sensor.

Questions about a specific monitor? Email sales@trigas-usa.com with the model and we will confirm the blend.