Bump Test Gas — Complete Guide for Gas Detector Safety Programs
Bump testing is one of the most important — and most commonly neglected — procedures for portable gas detector programs. This guide covers what bump test gas is, how often to do it, which gas to use for your detector, and how to set up an automatic supply program so you never run out. The gas we supply is produced in ISO/IEC 17025:2017-accredited laboratories, ships with a NIST-traceable CoA, and is available in all standard mixtures and sizes.
What is a bump test?
A bump test (function check) briefly exposes a detector to a known concentration of calibration gas to verify that each sensor responds and that the detector triggers its alarms. It does not adjust the sensor readings — it only confirms the detector responds. A detector that fails a bump test must be removed from service for full calibration or repair.
How often should you bump test?
| Standard / requirement | Frequency |
|---|---|
| OSHA 29 CFR 1910.146 (confined space) | Before each use |
| OSHA 29 CFR 1910.120 (HAZWOPER) | Before each use |
| MSA / BW / Industrial Scientific manuals | Before each use |
| ANSI/ISEA 104-2016 (IDLH) | Before each use |
Bottom line: for confined space entry, HAZWOPER, or any IDLH environment, bump test before every single use.
Bump test vs. calibration
| Bump test | Full calibration | |
|---|---|---|
| Purpose | Verify sensor responds and alarms | Adjust sensor to known concentration |
| Duration | 30–60 seconds | 2–5 minutes per sensor |
| Adjusts detector? | No | Yes |
| Frequency | Before each use | Every 30–180 days |
| Gas used per event | ~0.1–0.2 L | ~0.5–1 L |
Which bump test gas do I need?
| Detector configuration | Recommended gas | Part # |
|---|---|---|
| CO + H₂S + O₂ + LEL (standard) | 25ppm H₂S / 100ppm CO / 50% LEL / 18% O₂ | 34L-380 |
| MSA Altair 4X | 25ppm H₂S / 100ppm CO / 1.45% CH₄ / 15% O₂ | 34L-421 / 58L-421 |
| CO only | 100 ppm CO / N₂ | 34L-CO-100 |
| H₂S only | 25 ppm H₂S / N₂ | 34L-H2S-25 |
| O₂ only | 18% O₂ / N₂ | 34L-O2-18 |
| NO₂ sensor | 400 ppm NO₂ / N₂ | 34L-NO2-400 |
| SO₂ sensor | 20 ppm SO₂ / N₂ | 34L-SO2-20 |
| NH₃ sensor | 25 ppm NH₃ / Air | 34L-NH3-25 |
| Cl₂ sensor | 10 ppm Cl₂ / N₂ | 34L-CL2-10 |
Set up an Auto-Replenish program
Running out of bump test gas creates a compliance gap. To size a subscription: count your detectors × bump test frequency, at ~0.1–0.2 L per test, divided by cylinder volume. Rough guide: 17L for 1–2 detectors, 34L for 3–5, 58L for 6–10, 103L for 10+. Then choose a 30/60/90-day interval at trigas-usa.com for 8% off plus free shipping, with a reminder before each delivery and CoA/SDS included.
Bump test documentation — what to record
For confined space and HAZWOPER programs, record: date/time, instrument serial and model, calibration gas cylinder lot and part number, pass/fail per sensor, who performed the test, and the action taken on failure. Every Trigas USA cylinder includes a CoA whose lot number links back to the ISO 17025-accredited laboratory that produced the gas — a complete, auditable traceability chain to NIST standards.
Questions or help sizing a program? Call (786) 609-3221 or email sales@trigas-usa.com.