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Z Gard Sensors |
FAQ – Diesel Vs. Gasoline burning vehicles
Carbon Monoxide (CO) is similar in density to the air we breath. For
this reason, the gas does not tend to migrate. As a result, CO sensors
are recommended to be mounted where human beings will breath. A mounting
height of 3’ – 5’ feet from the floor is typical.
Nitrogen Dioxide (NO2 or NOx) is emitted from diesel burning
vehicles. NO2 is the gas of choice for detection purposes as technology
can react to it at low levels and provide ventilation or alarm
notification very quickly. NO2 is slightly more dense than the air we
breath, but, it is still typically recommended that sensor is mounted in
breathing range to protect inhabitants.
Why mount NO2 at ceiling level? In some cases, NO2 will have a
tendency to collect at the ceiling. This is due to the heat of the
exhaust gas, and, the configuration of vehicle exhaust (stacks that
point up vs tail pipe near ground). In some cases, it has been found
that NO2 will hover at the ceiling for up to hours after a vehicle as
left the dock/garage. If that gas is not detected early, high
concentrations will collect. In addition to NO2, sulphurous orders and
soot concentrate in the air. Once the exhaust gases cool, the NO2 will
migrate toward the floor. When the gas detection technology senses a
higher level of NO2, it will typically start ventilation and activate
audible and visual alarms. It is best to avoid high concentrations of
gas, sulphurous odors and soot. In these cases, an NO2 sensor mounted 12
– 18” from the ceiling will provide a rapid response and activate
ventilation systems as required.
EIP does not recommend CO2 detection for garage ventilation
CO2 is a component of some vehicle exhaust, but, it also results from
direct fired heating systems.
CO2 sensors, although appropriate for demand control ventilation, do
not typically perform well in garage ventilation applications.
It is EIP’s recommendation that CO and NO2 be utilized due to the
excellent performance of the technology available. |
