ARID completed a hydrocarbon emission test at a fueling site in the Pacific Northwest. This was a Stage II vac-assist site without an ARID Permeator, and the goal was to compare the total evaporative emissions with the figure predicted by ARID's proprietary Evaporative Loss Model (ELM). The total evaporative emissions are equal to the sum of the vent line emissions and the fugitive emissions. In-turn, the fugitive emissions for a site passing a standard leak decay test, are dependent primarily upon the average storage tank pressure. Key inputs into the ELM model included fuel storage tank temperature, fuel RVP, A/L ratio of Stage II system, ORVR penetration rate, and fuel throughput.
This was pioneering work, and by making direct measurements with a totalizing flowmeter and remote data aquisition gear, ARID very accurately quantified the total evaporative losses at this site. The sum of our measured vent emissions and the estimated fugitive emissions very nearly equaled to the total losses predicted by ARID's ELM. It should also be noted that the magnitude of these emissions far exceed the figures reported by sources such as CARB (California Air Resources Board) and the American Petroleum Institute (AP-42) on this category of emissions.
Please refer to "Vent Line and Fugitive Emissions Study" for more details.