by İpek Yavuz Konak
on 20 March 2018

Nowadays parking garages become widespread with increase of the population and vehicle usage. Parking garages are common in shopping malls and residances where population density is high. Carbonmonoxide 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 for detection and control. Vehicles operating with gasoline and diesel fuels exhaust toxic gases like carbonmonoxide and nitrogen dioxide. North America, England, Europe and other countries whcih have regulations about toxic gases in parking garages focus on carbon monoxide detection.

What is Carbonmonoxide?

Carbonmonoxide is a tasteless and odorless toxic gas. Carbonmonoxide gas occurs when substances that have carbon atoms like methane, benzine, wood and coal can not burn properly due to lack of oxygen. When carbonmonoxide gas is inhaled, it passes through lungs and dissolves in blood. There are proteins called hemoglobin in red blood cells, and the main function of hemoglobin is to carry oxygen for respiration. When carbonmonoxide gas dissolves in blood, it immediately bonds with hemoglobin proteins. Carbonmonoxide’s bonding tendency to hemoglobin is 200-250 higher than oxygen. So once a person inhales carbonmonoxide, his/her oxygen level in blood starts decreasing. Inhaling carbonmonoxide has severe effects like headache, nausea, vomitting, and fainting. Exposure to carbonmonoxide for long durations and high concentrations may lead to intoxication and death.

Carbonmonoxide concentration is measured by ppm ( particles per million). For example; 50 ppm of carbonmonoxide 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 carbonmonoxide during a day, TWA will be 15 ppm.

Exposure limit of carbonmonoxide

Exposure limit of carbonmonoxide 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:

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

Carbonmonoxide 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. CO gas detection system should be integrated to ventilation system of the parking garage. When carbonmonoxide level in the garage exceeds alarm level of the gas detection system, ventilation system starts to evacuate carbonmonoxide and lets fresh air come into parking garage. By the help of this application, people in the parking garage will not be poisoned.