Would it really be so bad to inhale your exhaust fumes?
What is VET?
Vehicle Emissions Testing (VET) determines the opacity (darkness) of the exhaust fumes emitted by diesel powered engines. The emitted smoke’s opacity is an indicator of the engine’s condition. The higher the opacity of the smoke, the higher the carbon black particulates being emitted and the higher the likelihood that there is an existing internal problem, or a problem is developing. Such issues can result in the engine lifespan being shortened or result in unnecessary costs unless remedial action is taken. More importantly for your business’s bottom line, Dark Smoke emanating from a diesel engine is an indication of incomplete combustion, belying unquantified fuel loss and furthermore increasing an engine’s running cost. Opacity monitoring can assist fleet managers (as a type of spot check) in monitoring unnecessary fuel loss and downstream maintenance complications.
Why should VET be done?
In our ever-growing society, the number of vehicles on our roads are increasing daily. This increase in vehicles has a negative impact on the environment around us as well as on human health. Diesel engines (point, non-point and mobile sources) emit more black carbon particulates than their petrol engine counterparts and thus the opacity diesel engine exhaust smoke is regulated throughout the world, including in South Africa. For more information on point, non-point and mobile sources see the eThekwini Air Quality Management By-Law (2018).
Emissions from diesel engines contribute to the production of ground-level ozone (the main ingredient in smog) which damages crops, trees and other vegetation. Another delightful by-product is acid rain, which affects soil, lakes and streams and enters the human food chain via water, produce, meat and fish. These emissions also contribute to property damage and reduced visibility.
Human Health Impact –
Exposure to diesel exhaust can lead to serious health conditions such as asthma and respiratory illnesses and can worsen existing heart and lung disease, especially in children and the elderly.
To reduce the environmental impact of diesel-powered engine exhaust fumes, the South African Government has introduced regulations which govern diesel vehicle exhaust emissions guided by The National Environmental Management (NEMA): Air Quality Act, 1998 (Act 107 of 1998), Model Air Quality Management By-Law for Easy Adoption and Adaption by Municipalities.
Local municipality is responsible for managing their own areas of jurisdiction by means of communicating and enforcing their own by-laws in regards to diesel vehicle emissions. These by-laws determine the maximum allowed exhaust emissions for all diesel-driven motor vehicles.
Along with the NEMA regulations, companies that are ISO 14001 accredited, perform vehicle emission testing to comply with their ISO 14001 accreditation as well as any internal environmental policies and programs that companies may have contributing toward their ESG initiatives.
How VET is done
The opacity of the smoke being emitted from a diesel-powered engine is measured through a Hartridge Smoke Meter which uses an optical sensor that measures the opacity of the smoke as it passes through the sensor. The measurement principal is based on light extinction detection. The opacity is then compared to municipalities’ limits to determine if the vehicle is compliant or non-compliant.
Apex Environmental utilizes the TEXA OPABOX Autopower, the latest exhaust gas analyser from TEXA, an Italian company with 30 years of design, industrialisation, and manufacturing of exhaust gas analysers.
- The OPABOX Autopower is a partial flow opacity meter designed for diesel engines. It incorporates the latest generation exhaust gas analysis chamber developed to conform to international standards.
- OPABOX Autopower is designed to be practical and versatile and meets the full range of requirements of mechanics in the field of exhaust gas analysis.
- The analysis chamber is incorporated in a practical trolley mounted on wheels with ball bearings. The analyser can therefore be moved effortlessly to the vehicle waiting to be tested.
- Thanks to Power Pack and Bluetooth technology, TEXA exhaust gas analysis solutions eliminate all those awkward cables trailing around the workshop, between the analysers and the display units, and between the analysers and the mains power supply too.
Vehicle Emission Testing is a simple procedure that takes less than 5 minutes per vehicle. The following procedures are followed to ensure the most accurate readings possible:
- The vehicle to be tested is required to reach normal operating temperature before testing.
- Once the vehicle has reached normal operating temperatures, two hard revs are given to remove any particulates that have settled in the exhaust system during the idling period.
- The probe is then inserted and secured in the exhaust pipe exit. The Diesel Smoke Meter samples the exhaust emissions through periods of idling and full, free acceleration.
- The sample is drawn through a Partial flow continuous gas sampling combined with a heated and temperature-controlled smoke chamber, within which a beam of high intensity light is passed. The amount of light which is scattered and/or absorbed is proportional to the amount of particulate matter (opacity) entrained in the exhaust emissions.
- The results are then recorded and compared to the relevant South African Emission Limit Values.