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electrical Issue

Gas Detection Alarm

A gas detection alarm means potential explosive atmosphere. Take it seriously—here's what to do.

Emergency: (877) 489-3727Start Diagnosis

What You're Experiencing

The LEL (Lower Explosive Limit) gas detection system has alarmed, indicating solvent vapor concentration has reached a potentially dangerous level.

Visual Signs:

  • LEL detector display showing elevated reading
  • Gas detection panel showing ALARM
  • Booth control panel showing LEL fault/alarm
  • Paint operation automatically shut down
  • Warning lights activated

Sound Signs:

  • LEL alarm horn or siren
  • Control panel alarm buzzer
  • Possible ventilation system sounds changing

Safety Risks — Read Before Proceeding

critical(NFPA 33 Section 15.3, OSHA 1910.107)

Explosive atmosphere

Action: LEL alarm indicates potential explosion risk. Do not create ignition sources.

high(OSHA 1910.134)

Worker solvent exposure

Action: Elevated vapor concentrations mean worker exposure. Evacuate if necessary.

Immediate Steps to Take

  1. 1

    STOP all painting immediately

  2. 2

    Do NOT create ignition sources (sparks, flames, switches)

  3. 3

    Evacuate personnel from booth and immediate area

  4. 4

    Check if exhaust fans are running at full speed

  5. 5

    Allow booth to purge for several minutes

  6. 6

    Check LEL detector reading—is it dropping?

  7. 7

    Do NOT assume it's a false alarm without investigation

  8. 8

    Check for spills, excessive solvent, or unusual conditions

Common Causes

Here are the most likely reasons you're experiencing this problem, ranked by how often we see them.

Inadequate Ventilation

common

Exhaust airflow has dropped, allowing solvent vapor concentration to rise above safe levels.

Excessive Solvent Use

common

More solvent is being released (heavy spraying, flushing, spills) than ventilation can handle.

Sensor Contamination

occasional

The LEL sensor is contaminated with paint overspray, affecting its accuracy.

Sensor Calibration Drift

occasional

The sensor has drifted out of calibration and is giving false readings.

Actual Dangerous Condition

occasional

There IS an actual elevated solvent vapor concentration—the system is working correctly.

Sensor Failure

rare

The sensor has failed and is alarming falsely.

Interactive Diagnostic Tool

LEL Alarm Response

Step 1 of 6

Are exhaust fans running at normal speed?

If unsafe at any point: If LEL reading is very high or not dropping, evacuate area completely. Call WERCS emergency line at (877) 489-3727. Do not re-enter until safe.

When to Call WERCS

While some issues can be resolved with basic troubleshooting, these situations require professional service:

  • LEL alarm and you cannot identify cause
  • Repeated or frequent LEL alarms
  • Sensor needs calibration
  • Sensor appears contaminated or failed
  • Ventilation issues causing vapor buildup
  • Need LEL system inspection

Priority Service Available

(877) 489-3727

Expert technicians nationwide

Gas Detection Alarm FAQ

Common questions about this issue

LEL (Lower Explosive Limit) is the minimum concentration of vapor in air that can ignite. Below LEL, there's not enough fuel. Above UEL (Upper Explosive Limit), there's not enough oxygen. The danger zone is between LEL and UEL. Paint booth ventilation keeps concentration well below LEL (typically alarm at 25% of LEL).
NO. Never ignore an LEL alarm based on smell. Some solvents have little odor at dangerous concentrations. The sensor is more reliable than your nose. Always treat LEL alarms as real until proven otherwise.
LEL sensors should be calibrated quarterly at minimum, and more frequently in harsh environments. NFPA 33 requires regular calibration verification. Most sensors also need periodic replacement (typically every 2-5 years depending on type).
False alarms can be caused by: sensor contamination (paint overspray), sensor drift (needs calibration), environmental interference (certain cleaning chemicals), or sensor failure. However, always assume the alarm is real until you investigate and confirm otherwise.

Have a question not answered here?

Call us at (877) 489-3727

Related Problems

Lel Calibration ErrorGas Detection FaultC1d1 Gas Sensor AlarmLow Airflow

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