Carbon Monoxide detection in parking garages

Nowadays parking garages have become widespread with increase of the population and vehicle usage. Parking garages are common in shopping malls and residances where population density is high. Carbon monoxide in the exhaust gases of the vehicles in parking garages lead to severe health risks for people.

Although many toxic gases are released within the exhaust gas of the vehicles, carbon monoxide is the primary gas requiring detection and control. Vehicles operating with gasoline and diesel fuels produce toxic gases like carbon monoxide and nitrogen dioxide. North America, UK, Europe and other countries which have regulations for toxic gases in parking garages focus on carbon monoxide detection.

What is Carbon Monoxide?

Carbon monoxide is a tasteless and odorless toxic gas. Carbon monoxide gas occurs when substances that have carbon atoms like methane, benzine, wood and coal can not burn properly due to the lack of oxygen. When carbon monoxide gas is inhaled, it passes through lungs and dissolves in the blood.

There are proteins called hemoglobin in red blood cells, and the main function of hemoglobin is to carry oxygen for respiration. When carbon monoxide gas dissolves into the blood, it immediately bonds with hemoglobin proteins. Carbon monoxide’s bonding tendency to hemoglobin is 200-250 higher than oxygen. So once a person inhales carbon monoxide, the oxygen level in their blood starts decreasing. Inhaling carbon monoxide has severe effects like headache, nausea, vomitting, and fainting. Exposure to carbon monoxide for long durations and high concentrations may lead to intoxication and death.

Carbon monoxide concentration is measured by ppm ( particles per million). For example; 50 ppm of carbon monoxide means that there are 50 molecules of carbonmonoxide in every 1.000.000 molecules in the air.

Also another method for measurement of carbonmonoxide is TWA (time weighted average). For example, if a person is exposed to 15 ppm carbon monoxide during a day, TWA will be 15 ppm.

Exposure limit of carbon monoxide

The exposure limit of carbon monoxide is determined by different authorities in the world.* Each authority determines different limits. Limits that Health and Safety Executive’s (HSE) publication EH40/2013, OSHA, NIOSH, and ACGIH are stated below:

Carbon monoxide detection systems should be designed and applied according to the exposure limits that relevant authority determined.

Carbon monoxide gas detectors should have two alarm levels with two separate relays for each alarm level. These alarm levels should be adjusted according to LTEL (Long Term Exposure Limit) and STEL (Short Term Exposure Limit) levels. A CO gas detection system should be integrated into the ventilation system of the parking garage. When the carbon monoxide level in the garage exceeds alarm level of the gas detection system, the ventilation system starts to evacuate carbon monoxide and lets fresh air come into the parking garage. By the help of this application, people in the parking garage will not be poisoned.

Another important issue is the location of gas detector. Since the density of carbon monoxide is similar as air, CO detectors should be mounted at a height of 150 cm on the wall. Also the detector should be mounted 150 cm away from the gas source.

Carbon monoxide is a very toxic gas that causes severe effects on health. If the necessary precautions are not taken, carbon monoxide exposure may lead to intoxication and death. For this reason, carbon monoxide gas detection systems should be applied in all places that has an exposure risk.

*Authorities and technical terms:

OSHA: Occupational Safety and Health Administration

NIOSH: The National Institute for Occupational Safety and Health

ACGIH: American Conference of Governmental Industrial Hygienists

HSE: Health&Safety Executive

COSHH: Control of Substances Hazardous to Health Regulations

EH40/2013: Document which is published by Health and Safety Executive, due to European Commission Directives 80/1107/EEC and COSHH

TWA: Time Weighted Average

LTEL: Long Term Exposure Limit- 8 hours

STEL: Short Term Exposure Limit- 15 minutes

PEL: Permissible Exposure Limit

REL: Recommended Exposure Limit