20ppm H2S, 60ppm CO, 15%O2, 1.45% vol. CH4, 58L | MSA

This is a 58-liter calibration (or bump-test) gas cylinder containing a quaternary gas blend tailored for multi?gas portable detectors (especially for LEL/combustible, CO, H?S, and O? sensors). The gas mix is:

• Methane (CH?): 1.45% by volume — used to simulate a low-level combustible gas (equivalent to ~58% LEL when expressed as a pentane-simulant). 
• Oxygen (O?): 15.0% — lower than atmospheric (~20.9%) to verify response of oxygen sensors.
• Carbon Monoxide (CO): 60 ppm — for calibrating CO sensors.
• Hydrogen Sulfide (H?S): 20 ppm — to test H?S sensor response.
• Balance gas: Nitrogen (N?). (Used as inert diluent.)

This blend is especially suitable for bump testing or calibrating 4-gas detectors (e.g., those measuring combustible, O?, CO, and H?S), particularly MSA multi-gas detectors (Altair series, etc.). The mix is useful for simulating realistic hazard conditions with moderate levels of methane, CO, and H?S, plus reduced oxygen.

The cylinder is made of aluminum, making it reasonably lightweight and portable for field calibration. It is a non-refillable cylinder (for Gasco’s “58L” line), with a C?10 (5/8″?18 UNF) valve connection, compatible with standard calibration regulators. The service pressure of the cylinder is 500?psi.

Calibration Testing Gas, 58 L, 1.45% CH?, 60?ppm CO, 20?ppm H?S, 15% O?. According to MSA’s catalog, this gas is prepared gravimetrically using NIST-traceable weights, so it's very accurate.

Cylinder Volume

58 L

Cylinder Material

Aluminum alloy

Service Pressure

500 psi (≈ 34.5 bar)

Regulator Compatibility

C10-compatible regulators (e.g., MSA regulators, or 700-series demand-flow) can be used.

Accuracy / Certification

Supplied with a Certificate of Analysis (CoA); MSA indicates gravimetric preparation with NIST-traceable weights for its cylinders.

Intended Use

Bump testing and span calibration of portable multi?gas detectors (especially 4-gas devices: LEL/CH?, O?, CO, H?S)

Safety / Handling Considerations

- Flammable component (CH?): handle with appropriate care and regulators.
- Toxic gases (CO, H?S): use in well-ventilated areas or under controlled gas flow.
- Use proper calibration regulators.
- Store cylinder upright, secured, and according to HAZMAT guidelines

Shelf Life / Storage

Depends on manufacturer / supplier; check certificate / expiration on each cylinder. (Typical calibration gas cylinders have a recommended “use before” or “expiry” date based on gas stability.)

Common Applications

- Calibration of MSA Altair 4X/5X and similar multi-gas detectors.
- Routine bump?tests / functional tests as part of safety maintenance in industrial environments.
- Audit or compliance checks requiring documented calibration gas traceability.

Advantages / Benefits

• Versatile Mix: Contains four important gases (combustible, O?, CO, H?S), so only one cylinder needed for many 4-gas detector calibrations.
• Field-friendly: 58 L aluminum cylinder is reasonably portable yet offers enough gas for multiple calibrations.
• Traceable Accuracy: Gravimetrically prepared with NIST traceability (for MSA variant) ensures reliable calibration.
• Widely Supported: Compatible with standard calibration regulators and commonly used by MSA detectors.
• Safety?Relevant: The specific gas concentrations are such that they simulate realistic hazard conditions without being extreme, making them good for functional / bump checks.

Limitations / Drawbacks

• Limited Gas: Even 58 L will run out if used for a large number of calibrations / bump tests — you need to track usage.
• Hazard Risk: Contains flammable and toxic gases — requires careful handling, correct regulators, and safe environment.
• Shelf Life: Gas stability over time can degrade; older cylinders may yield inaccurate calibration.
• Cost: Premium calibration gas mixes (especially with traceable certification) may be more expensive than simpler blends.