How to Bump Test Your Draeger Gas Detector: A Quality Inspector's Checklist

Who This Checklist Is For

If you work in industrial safety, hospital boiler rooms, or any facility that relies on Draeger gas detectors, air monitors, or a Draeger bump test station, this checklist is for you. I review about 200+ safety instruments annually in my role as a quality inspector, and I can tell you: the bump test is the single most skipped step. People assume it's a formality. It's not.

This checklist covers the 5 steps you need to run a proper bump test. I've rejected roughly 18% of first-calibration attempts in 2024 because of silly mistakes that could have been caught with a simple checklist. Let's fix that.

Step 1: Verify Your Gas Cylinder

Before you even touch the detector, check the calibration gas cylinder. Honestly, this is where most failures start.

• Check the expiration date — gas does expire. Using expired gas gives you a false pass or fail.
• Confirm the gas concentration matches the detector's settings. A cylinder labeled "100 ppm CO" but your detector expects 50 ppm? That's a mismatch.
• Check the regulator — a loose fitting can leak gas and give you a weak reading.

Rookie Mistake I Made: In my first year, I grabbed a cylinder that looked full. The pressure gauge was fine, but the gas was 18 months past expiry. Cost me a full re-test of 40 units and a call to the supplier. Now every cylinder gets a sticker with the expiry date.

Step 2: Connect the Bump Test Station

If you're using a Draeger bump test station, make sure it's clean and the hoses aren't kinked. A kinked hose restricts flow, and the detector thinks there's no gas. Or rather, it thinks there's less gas than there is.

• Inspect the gas port for debris or corrosion.
• Verify the station is set to the correct gas mixture. Some stations support multiple gases; select the one you're testing.
• Secure the detector properly. If it's loose, the seal won't hold, and gas escapes.

People assume connecting a station is foolproof. The reality is that a dirty port is the #1 cause of failed bump tests in our Q1 2024 audit — and it takes 10 seconds to wipe it down.

Step 3: Run the Bump Test

Start the test according to the manufacturer's instructions. For Draeger detectors, this usually means pressing a button or letting the station auto-start.

• Watch the display — it should show a rapid rise in gas reading, then level off near the expected concentration.
• Timing matters. Most bump tests take 30-60 seconds. If the reading never hits the target, stop and investigate. Actually, don't wait — if it doesn't reach 90% of the expected value within 20 seconds, flag it immediately.
• Listen for the alarm. The whole point of a bump test is to confirm the alarm actually sounds when gas is present. If the detector reads gas but doesn't alarm, that's a fail.

Penny-Wise, Pound-Foolish Example: Saved $50 by buying a no-name calibration gas. It didn't match the required purity. Impurities damaged the sensor, and replacing it cost $300. Net loss: $250, plus downtime.

Step 4: Record the Results

Documentation isn't just paperwork — it's your proof that the equipment is safe to use. I've seen facilities fail OSHA inspections simply because they couldn't produce records.

• Log the date, time, and who performed the test.
• Record the gas reading and alarm status. Pass or fail.
• Note any deviations — e.g., gas cylinder serial number, ambient temperature (extreme temps affect readings).

I'd argue that a proper log is as important as the test itself. If you can't show you did it, you didn't do it.

Step 5: Troubleshoot Failures

If the bump test fails, don't just retest and hope. Troubleshoot systematically:

• Check gas flow — is the cylinder empty? Is the regulator open?
• Check the sensor — is it past its service life? Draeger sensors typically last 2-3 years.
• Check for contamination — oil, moisture, or dust on the sensor can cause drift.

In our facility, about 60% of failed bump tests are due to gas issues, 30% to detector maintenance, and 10% to user error. That said, your numbers might vary if you're in a harsher environment.

Important Notes (Things People Get Wrong)

• A bump test is not a calibration. It only checks that the detector responds to gas, not that it's accurate. Use a full calibration quarterly.
• Temperature and humidity affect results. If your bump test station is in a hot warehouse, readings may be off. Compensate or move to a climate-controlled area.
• Different equipment, different rules. A biosafety cabinet or an anesthesia workstation has its own verification protocols. Don't try to apply this exact checklist to those. For example, how does a fetal monitor work? Completely different principle — ultrasound vs. electrochemical sensor. Know your device's limits. A vendor who says "our procedure works for everything" is not a vendor you should trust. Specialization matters.

Bottom line: A decent bump test routine takes 2 minutes and saves you from false confidence. Use this checklist, adapt it for your gear, and never skip it.