GrayWolf Sensing Solutions - 1260GSS Four Function Probe
Temperature, Humidity, Dewpoint,
Carbon Dioxide (CO2), Carbon Monoxide (CO)

The 1260GSS Four Function Probe is designed for use with the GrayWolf IAQ Surveyor multifunctional datalogger instruments. The probe has fast response sensors, which reduces the time needed to conduct spot checks and walk- through surveys, minimizing the wait for sensors to stabilize when moving from zone to zone.

The probe monitors temperature and relative humidity, from which the IAQ Surveyor instrument calculates the dewpoint temperature, and the concentration levels of carbon dioxide (CO₂) and carbon monoxide (CO). A dedicated temperature sensor, fitted close to the CO₂ sensor body is used for temperature compensation for the CO₂ sensor. Temperature compensation calculations are carried out within the IAQ Surveyor so that, in practice, a total of five sets of data are multiplexed to the Surveyor. It will not function with the Zephyr series of instruments.

Indoor Air Quality is a function of several factors of which temperature is the most important thermal comfort measurement. It is typically controlled between 68°F to 70°F and (20°C to 25°C), and sudden temperature changes can cause discomfort, and indirectly affect other comfort parameters such as relative humidity. By following the air temperature for a week, it is possible to follow a building’s air handling behavior.

Relative Humidity (Rh) and dewpoint (absolute humidity) measurements verify conditions are within a comfortable range for occupants. They also provide data ensuring the environment is not conducive to microbial growth or verify that laboratories, computer rooms, storage areas, etc. have acceptable moisture levels. A low % Rh is not an answer to all IAQ problems since if the % Rh is too low, eye irritation, skin irritation and respiratory tract problems may arise. Dust is generally more of a problem in low humidity situations. Most viruses grow best in low temperature/high humidity conditions. Formaldehyde emissions also increase when both temperature and Rh increase. Hence, Rh limits for IAQ purposes are usually specified as being between 30% and 60%.

The Carbon Dioxide (CO₂) concentration level is an important parameter to measure as it provides a practical basic indicator of ventilation, and accurately calculates outdoor air ventilation and air dilution rates. As a surrogate indicator of air quality, CO₂ provides a natural tracer through the building’s ventilation system.

Carbon Monoxide (CO) levels provide an indication of improperly ventilated combustion processes to verify occupants are not at risk from this potentially lethal specific pollutant. This is particularly important where direct-fired heat exchangers are used. Mechanical damage or corrosion to the heat exchanger causes mixing of the combustion gas with the return air, resulting in a buildup of CO inside the building. Inhalation of CO is highly toxic even at relatively low concentrations, and in high concentrations can cause immediate collapse and death. Any concentration in excess of a few ppm should be investigated.

The IAQ Surveyor instruments can be used for quick spot-checks, walk-through surveys, or left to monitor over time; storing days, weeks, or even months of data.