Frequently Asked Questions

1. Is the PERMEATOR system compatible with various Stage II vapor recovery systems?
Yes, our system can be retrofit to any gasoline dispensing facility; including uncontrolled stations and those using balance; dispenser-based vacuum assisted systems and centralized vacuum assisted systems.

2. Do we have to break ground to install the PERMEATOR unit?
Maybe, depends on the specific vapor-piping configuration. If the storage tanks are manifolded underground, no excavation is required. If storage tanks are not manifolded below ground, minimal excavation can be used to allow for tie-in of the vapor return line.

3. How do I know that storage tank evaporative losses are between 0.1% and 0.5% of a gasoline station's throughput?
Third party testing has verified that the evaporative losses are within the range stated above. The variation in the range is due to various site-specific factors such as fuel RVP (Reid Vapor Pressure), stored fuel temperature, altitude, and the volume of air ingested relative to volume of fuel dispensed.

4. How do I know the PERMEATOR system really works?
Third-party testing as well as a Major Oil internal study have consistently found the PERMEATOR System to provide recovery efficiencies of between 99.27% and 99.8%. The gasoline vapor concentrations and flow rates from the feed, rich vapor return and clean air exhaust lines were measured to generate the recovery efficiency figures. The PERMEATOR also earned three CARB (California Air Resources Board) certifications (Executive Order G-70-209, VR-201-Z and VR-202-Z). European approvals include German TUV Rheinland and Swiss BULVAL/EMPA. In addition, testimonials from customers verify the fuel savings figures.

5. Is the system safe?
Yes, the unit has received safety approval from the German PTB, and UL 698A approval here in the United States. The vacuum pump is manufactured with ductile iron and is equipped with internal flame arrestors. The vacuum pump is rated to withstand pressure spikes of 225 psig. Worldwide, over 650 systems have been sold without any safety problems. Thus, the system is robust and commercially proven.

6. Life of membrane?
Existing terminal vapor recovery systems installed in Europe since 1989 are operating with the same membranes. A 15-20 year life is anticipated for our application; replacement involves only the re-packing of the module, an entirely new module does not have to be purchased.

7. Is current ATG (Automatic Tank Gauge) technology sensitive enough to measure existing evaporative losses and the savings in salable product with the PERMEATOR system?
Theoretically, these systems are capable of measuring 1/1000 th of an inch level differences. For example, in a 10,000 gallon horizontal tank, at half height (8 ft. diameter, 1/2 height = 48 inches), one inch of gasoline is equivalent to about 135 gallons. Product losses for a station pumping 150,000 gallons per month (with V/L = 1.1) are on the order of 8 gallons per day, which requires a measurement accuracy of 8/135 or .06 inches; well within the stated accuracy of these gauges. However, as a practical matter, the lack of temperature compensation on dispensed volumes introduces errors in the ''over and under'' gross volumes reported by these gauges. As such, reliance on these figures for inputs into more sophisticated algorithms designed to provide statistical inventory reconciliation can introduce large errors.

8. Will water vapor harm the membrane?
No, water vapor passes through the membrane.

9. What happens if the station loses power?
The PERMEATOR system does not create any restrictions to the existing system - the station will operate as though the PERMEATOR is not installed.

10. What about diesel vapor recovery?
No need, the diesel vapor pressure is too low to justify a recovery system.

11. Do you need a PERMEATOR system on each storage tank?
No, one system handles the vapors from manifolded storage tanks. The vapor return stream is directed to the lowest grade fuel storage tank. A standard PERMEATOR system has processed vapors from stations pumping over 2 million gallons (8 million liters) of gasoline per month.

12. What are the typical maintenance items?
Maintaining oil level in the vacuum pump - checked continuously via our oil level sensor and remote data acquisition gear. An oil change is recommended annually or after 5,000 hours of operation.

13. What is the warranty on the equipment?
Thirty-six months.

14. Would ARID put on a class for our technical personnel to learn the operation, installation and maintenance of the PERMEATOR unit?
Yes. We offer training for technicians to earn designation of CPT – Certified Permeator Technician.

15. Where does the unit get mounted?
The PERMEATOR can be placed on the canopy roof, at grade or below ground. Connections to vent pipes are made for the Feed and rich vapor return lines. Ninety five percent of our installations are made at grade, with the balance done on canopy roof.

16. How much does a standard unit weigh and what are the dimensions?
A standard unit weighs about 750 pounds (340 kg) and has dimensions of 3 ft. W x 3 ft. D x 5.5 ft. H. (91 cm wide x 91 cm deep x 1.7 m high).

17. What are the dimensions of the Control Panel?
The NEMA-12 Control Panel dimensions are 20” x 16” x 9”.(51 cm x 41 cm x 23 cm)

18. Will the increased proportion of ORVR equipped vehicles take away the need for your system?
No, it will amplify the need. As more ORVR vehicles enter the fleet, the air ingestion into storage tanks will increase with an associated increase in evaporation. Please note that the system works well on fueling stations which do not use any type of Stage II (VR2) vapor recovery system.

19. Does your system impact the efficiency of Stage I vapor recovery?
Yes, since the storage tank vapors will be at a high equilibrium concentration, evaporation losses from the tanker truck during product deliveries will be reduced. Also, pressure spikes and fugitive losses during deliveries will be reduced. In addition, the recovery efficiency at the bulk terminal will be increased since the concentration of returned vapors in the bulk tanker will be increased to saturation levels (40%-60%, by volume).

20. Is the system approved for recovery efficiency/fire safety by any organization?
Yes, in Europe, the German TUV Rheinland has approved the system for recovery efficiency and the German PTB has approved the safety of the unit. For North America, the vacuum pump uses a UL listed electric motor rated for Class I, Div. I, Group C & D environments, and the control panel and associated sensors carry a UL 698A approval. ARID's proprietary Evaporative Loss Model (ELM) has been verified time and time again on PERMEATOR installations around the world. The magnitude of the savings yields after-tax internal rates of return between 15% and 95%, depending on site-specific factors. Also in the USA, a third party study was conducted at a high volume site in Florida with oversight from USEPA, State DEP, and local Health Department to quantify the magnitude of the emissions and associated savings with PERMEATOR.

21. Is this technology currently in-use anywhere (USA or worldwide)?
Yes, in the United States, PERMEATORS have been installed within the states of Arizona, California, Colorado, Delaware, Florida, Georgia, Hawaii, Illinois, Kentucky, Maryland, Massachusetts, Michigan, Nevada, New Hampshire, New Jersey, New York, Ohio, Oregon, Pennsylvania, Texas, Virginia, Washington and Wisconsin.

Internationally, dispensing facility units based on membrane technology are operating in China, Germany, Italy, Japan, Kuwait, Luxembourg, Mexico, South Korea, and Switzerland. The customers include Avia, BK, BMW, Chevron-Texaco, Copal ARAL, CPC, DEA, Erg, GPR, KNPC, Porsche, Q-8 Oil, Shell, and Uny Oil.

Bulk terminal gasoline vapor recovery systems using membranes have been successfully operating throughout the world since 1989. Each of the 250 large scale systems installed since 1989 have been consistently operating in tank farms and ship loading terminals without any membrane replacements. The performance and long-term stability of these hydrocarbon-selective membranes are commercially proven and such systems are considered an established technology in Europe.

Recently, ARID has used the PERMEATOR membrane technology to retrofit existing Carbon Adsorption units at a PetroDiamond bulk terminal in Long Beach, CA. The loading rates were increased while at the same time, the emission factor has been reduced from .08 lbm/1,000 gallons loaded to .0015 lbm/1,000 gallons loaded.

22. Are competitive systems based on membrane technology being used to recover gasoline vapors at an efficiency greater than 95%?
We are not aware of any commercially proven and robust competitive membrane based systems operating trouble-free at high volume retail stations.

23. Has ARID published any information in Trade Journals or Magazines related to gasoline marketing?
Yes, please refer to “Membranes, Molecules and the Science of Permeation”, TP Tiberi, Petroleum Equipment & Technology (PE&T), April 1999; page 30-34; “Some Fugitive Emissions Remain at Large”, TP Tiberi, PE&T, August 2000, pp. 29-32; “Vapor Recovery Around the World”, TP Tiberi, PE&T, September 2000, pp.16-20. These and other publications are available in the Archives at

Also see for archived TV coverage of ARID.

24. Is the PERMEATOR system or any key components covered by patents?
Yes, patents owned, assigned to or licensed by ARID include the following; 6,836,732; 4,994,094; 5,537,911; 5,220,799; 5,367,882; 6,059,856; 8,060,335B2, P4410597; P3270475; and PCT/DE95/00383. Also, the following US and European patents cover the process technology, membrane and module technologies: 4,673,418; 4,695,380; 4,818,452; 4,933,085; 5,076,923; and 0752974.

25. What is the nominal purchase price of PERMEATOR and the price range based on specific station conditions?
ARID provides our PERMEATOR system to customers through either a capital equipment purchase or under an operating lease. The savings in salable gasoline inventory exceed the monthly payments made by the end-user, including operating expenses. On purchased units, the magnitude of the savings yield after-tax internal rates of return are between 15% and 95%, depending on site-specific factors. The typical payback period on purchased units ranges from 1 year to 4 years.

26. Is it possible to have a PERMEATOR system installed without making any up-front payments to ARID?
Yes, there are two options relating to acquiring the PERMEATOR without significant capital outlays:

  1. Operating Lease based on a % of monthly savings
  2. Capital Lease

27. Do different size tank capacities present a problem?
No, headspace pressures will equalize.

28. Does the membrane accumulate hydrocarbons or become depleted?
No, the membrane selectively separates hydrocarbon molecules from air.