GasAlertQuattro Special Conditions for Measuring Different Gases

Different gases will require different levels of safe measurement. It is for this reason that we should briefly look at the acceptable parameters for each type of hazardous gas that the GasAlertQuattro will detect. This is but a general overview. For more detailed descriptions, please refer to page 32 of the owner's manual.

Oxygen

The maximum levels of oxygen that can be measured are atmospheres of up to 25% oxygen by volume. It is important to note that levels between 20.5 and 21.3% will simply read as 20.9%. The unit will take 32 seconds to warm up and an additional two minutes (120 seconds) to stabilize before it will be safe to use. Values that fall within .2% of the span concentration will simply be listed as a single number.

LEL Measurements

The GasAlertQuattro has the ability to measure levels of methane from 0 to 100%LEL in an atmosphere. Currently, the lower exposure limit (LEL) is defined as no more than 4.4% of methane by volume in an environment. The warm up and stabilization times are the same as oxygen as they are for methane. However, particular attention must be paid that the unit is kept free from all particulates and poisons that may interfere with the sensor. A list of these contaminants can be found in your owner’s manual. Finally, the measurement of other hazardous gases simultaneously in the environment may affect the accuracy of LEL methane readings. This should be taken into account during the calibration process.

Also, there are other gases that will display different readings (depending on the parameters of the measurements). This is specifically in reference to carbon monoxide and hydrogen sulfide. For example, extremely low readings of carbon monoxide will simply read as “0” on the LCD display. Hydrogen sulfide readings are only shown if the gases exists in under 200 parts per million (PPM). Any amount over 200 PPM is displayed as +OL.

Changing from LEL to Volume Percentages

There may be times when a direct volume reading is preferable over a lower explosive limit observation. This will require that the setpoints also be changed to avoid a potentially dangerous misinterpretation of the readings. This process is explained on page 10 of the owner’s manual.

There may be issues with sensor cross-sensitivities. This can impede the accurate measurements of potentially harmful and even fatal gases. Should this be suspected, it is best to contact BW or a qualified technician for further troubleshooting solutions. If an atmosphere is thick with dust or particulate matter, the degree of accuracy may likewise be hampered. This should be considered before using the device.

For a further summary as well as a detailed list of measurement ranges, target gases and other issues, please refer directly to pages 33 and 34 of the owner’s manual.