| 100% LEL | Maximum Instrument Reading |
| 50% LEL | 1/2 Amount Needed to Ignite Natural or Propane Gas |
| 20% LEL | Begin to Smell Gas Odorants |
| 10,000 PPM | Begin to Smell Gas Odorants |
| 500 PPM | Visible Bubbles from Leak Detection Solution |
| 100 PPM | Strong Instrument Tick |
