Product Description
4-Gas Calibration Gas – 25 PPM H2S / 90 PPM CO / 2.5% (50% LEL) CH4 / 20.9% O2 – 66L C-10 Cylinder
This H₂S 25 PPM / CO 90 PPM / CH₄ 50% LEL / O₂ 20.9% calibration gas is engineered for routine calibration and bump testing of portable four-gas monitors used in confined space entry and industrial safety applications.
The concentration profile reflects one of the most commonly specified OSHA-aligned 4-gas blends for:
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Confined space entry programs
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Wastewater treatment facilities
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Oil & gas operations
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Utility maintenance crews
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Industrial hygiene monitoring
The 50% LEL methane concentration (2.5%) provides accurate combustible sensor verification while maintaining safe and controlled calibration exposure levels.
Gas Concentrations
| Component | Concentration |
|---|---|
| Hydrogen Sulfide (H₂S) | 25 PPM |
| Carbon Monoxide (CO) | 90 PPM |
| Methane (CH₄) | 2.5% (50% LEL) |
| Oxygen (O₂) | 20.9% |
| Balance | Nitrogen |
Cylinder Specifications
| Property | Value |
|---|---|
| Cylinder Size | 66L (2.3 ft³) |
| Pressure | 1150 psi |
| Cylinder Specification | C-10 |
| Cylinder Material | Aluminum |
| Gas Reactivity | Reactive |
Reactive multi-gas blends require proper storage and regulator compatibility to maintain concentration stability and calibration accuracy.
Application & Compatibility
This 4-gas calibration mixture is suitable for most major portable multi-gas monitors used for toxic, combustible, and oxygen detection, including models from BW, MSA, Industrial Scientific, RAE Systems, and Dräger.
Common uses include:
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Daily bump testing
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Routine sensor calibration
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Compliance documentation
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Safety audits
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Pre-entry confined space verification
The 66L cylinder size provides a strong balance between portability and calibration longevity for field technicians.
Need a Different Blend or Cylinder Size?
If you do not see the exact gas concentration, LEL percentage, or cylinder size you require, contact our calibration gas specialists. We can supply custom multi-gas blends tailored to your detector model, regulatory requirements, or site-specific hazard profile.
Call our calibration gas specialists. We can build custom multi-gas blends tailored to your detector model, regulatory requirements, or site-specific hazards.
