Guide
Vehicle Emissions Gas Detection
The gases emitted by diesel and gasoline engines, Carbon Monoxide (CO) and Nitrogen Dioxide (NO2), present significant health risks when concentrations become too high. Both national and local codes are enforced to promote safety in structures where these gases can accumulate. Facilities such as parking structures, loading docks, and delivery warehouses can ensure compliance with these codes by installing a gas detection system that monitors gas levels and automatically starts ventilation as needed. This type of system can drastically reduce operating costs by limiting fan running time.
Shop Vehicle Emission Detectors
Where Vehicle Emission Detectors are Required
Distribution Centers
Parking Garages
Vehicle Depots
Loading Docks
Vehicle Maintenance Garages
How to Buy A Vehicle Emission Detection System
CTI published a helpful brochure that explains the best way to design a CO/NO2 detection system for your parking structure, distribution center, or vehicle depot.
Electrochemical Sensor Technology
The CTI DuoSense-M detector uses an electrochemical sensors which are accurate, reliable, and long lasting. Electrochemical cell technology is very specific to only CO and NO2 and will not alarm in the presence of other gases. These cells are housed in a well-vented polycarbonate enclosure which allows for the circulation of air while also protecting the cells from damage. The electrochemical sensor is an outstanding choice for personnel protection throughout most facilities.
The Benefits of Vehicle Emissions Gas Detection
Parking Garages, Vehicle Depots, and Distribution Centers all have the potential to reach dangerously high levels of Carbon Monoxide and/or Nitrogen Dioxide gases. There are numerous institutions, societies, organizations and government agencies such as ASHRAE, IMC, UMC & UBC that have established codes and standards to address the limits of CO and NO2 for parking structures. Most building codes allow for demand-based ventilation in parking structures by monitoring CO & NO2 levels. Proper ventilation and air flow is necessary to protect people, but how often and how much ventilation is needed? Using CO and NO2 detectors to monitor gas levels and to turn on ventilation as needed not only protects people, but also saves on energy costs.
SHOP VEHICLE EMISSIONS GAS DETECTORS
DuoSense Modbus Detector
Duo Sense Controller MVE
CO and NO2 Sensor Elements
Fan Controller
Horn Strobe
Regulatory Concentrations of Interest
There are several CO and NO2 thresholds to consider
CARBON MONOXIDE
OSHA Limits
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- PEL=50ppm
- TWA=25ppm
- Ceiling= 200ppm
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NIOSH Limits
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- REL=35ppm
- Ceiling=200ppm
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NITROGEN DIOXIDE
OSHA Limits
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- STEL=1ppm
- Ceiling=5ppm
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NIOSH Limits
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- STEL=1ppm
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Alarm Levels and Recommended Outputs
See below table for CO an d NO2 detection alarm levels and outputs.
| Gas | Alarm Setpoint | Action |
| CO | 0-200ppm
Exact setpoints can be determined by the owner, but shall not exceed 200ppm. |
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| NO2 | 0-10ppm
Exact setpoints can be determined by the owner, but shall not exceed 10ppm |
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Detector Placement
Based on typical construction, a sensor should be placed on every other support column in an alternating pattern. This will ensure that no area is left unprotected.
Detectors should be mounted approximately 3 – 5 feet above finished floor, in the typical human breathing zone.
Detection Range/Radius
Each DuoSense-M has a detection radius of 50 feet. The sensor element uses the diffusion method to evaluate and monitor the surrounding air quality and measure NO and CO2 levels.
