This year, the U.S. Environmental Protection Agency (EPA) granted a partial waiver in response to the Clean Air Act, allowing fuel manufacturers to sell gasoline with up to 15% ethanol volume for use in MY2001 and newer light-duty vehicles.

Clearing the Air on Evaporative Emissions Regulations

This year, the U.S. Environmental Protection Agency (EPA) granted a partial waiver in response to the Clean Air Act, allowing fuel manufacturers to sell gasoline with up to 15% ethanol volume for use in MY2001 and newer light-duty vehicles. Under the new ruling, the fuel blend known as E15 (contains up to 15 percent ethanol) can be sold for use in passenger vehicles including cars, SUVs, and light pickup trucks[1]

Further, in June of this year, the EPA finalized a warning label for E15 to be used on the pumps at gas stations, effectively clearing for the commercialization of E15. These recent developments have only fueled debate on the controversial issue of fuel emissions and led to questions on how legislation will evolve for fuel lines within smaller engines. Strong lobbying efforts by ethanol producers, on one side, and motor equipment manufacturers, on the other, continue to keep the subject top of mind among the industry and regulators alike.

Companies like Saint-Gobain Performance Plastics, a leading manufacturer of fuel tubing, are not so concerned, however. For them, the issue was primarily a scientific question – and one for which they have already identified a solution. Mark Colton, Product Development Manager, Applications Engineering at Saint-Gobain, explains.


1.      Why is there so much contention around the EPA raising the percentage of ethanol in gasoline?

The EPA’s concerns stem from the harmful effects on the environment of hydrocarbons. These molecules are emitted by engine exhausts when fuel is burned. Concern for air quality has led the agency to mandate higher percentages of ethanol (which burns clean) in fuels.  As of January, requirements now stand at 15% for cars and light trucks, which is blend E15.

It is important to bear in mind, however, that exhaust emissions are only one way that hydrocarbons escape into the atmosphere.  They also evaporate within the engine naturally and escape through fuel tanks, lines, and connections. This has led the EPA to simultaneously tighten mandates on permeation rates for fuel equipment.

The EPA has been regulating significant hydrocarbon emissions for some time now, but up until this point it has focused on the automotive industry as the primary source of pollution. It is still in the process of testing other types of engines, including those in off-road vehicles, boats, and power equipment, but the reality is that, as E15 becomes available at gas stations, the new blend may mistakenly be put into other fuel powered equipment, which has the potential to cause issues.


2.      Why is this such a concern for the fuel-line industry?

If the percentage of ethanol in the fuel is increased, the resulting mixture becomes more evaporative. Ethanol is a much smaller molecule than tubes have been designed to deal with and as a result has a far greater tendency to pass through existing materials, so the permeation rates skyrocket. Traditional tubing, therefore, is unable to prevent this increased evaporation and cannot meet EPA standards.

An increase in permeation also damages the tubes themselves.  Fuel acts as a solvent, causing the tubes to loose flexibility and become brittle.  This greatly reduces the operational life of the product.

With a certain array of materials, the industry can typically handle an ethanol content of around 10% up until now. But when you face higher ethanol content, it becomes increasingly difficult to keep it contained and you find that traditional tubing is no longer sufficient to meet the permeation numbers any more.

In a sense, the industry has been hit twice in one go. First, the ethanol content of fuel is creeping up, which makes it more difficult to contain. At the same time, the number of grams of emission per day that fuel-line manufacturers need to meet for their products is becoming tighter. That’s what makes it so difficult – the specifications for fuel-lines are tightening up, while simultaneously the fuel is becoming harder to contain.


3.      So what advances have been made to meet this demand? Are they sufficient?

At Saint-Gobain Performance Plastics (SGPPL), we have been developing new formulations for SGPPL products since the beginning of 2007 and currently have four different designs available that can meet the increased EPA requirements.

The approach has been to completely refresh existing products from both a technological and material standpoint. By moving into multi-layer designs for tubes – rather than using a single layer of one material – and including in this a layer of barrier material that is able to contain the fuel mixture far more effectively, permeation rates can be brought down to acceptable levels.

We are now able to offer an array of products that will solve the problem for our customers and enable them to meet the necessary regulations – before those regulations have even gone into effect. That means no down time in operations and no costly repairs or maintenance.


4.      What industries and applications are affected by these changes?

There are a number of applications that are affected now. One prominent application is SORE – Small Off-Road Engines; another is marine engines. But there are also huge implications for the outdoor power and landscape equipment industries as well. Technologies that are affected could range from snowmobiles to recreational boats, and from lawnmowers to weed trimmers and chainsaws.

As you can imagine, there was one set of implications when it was just cars that the EPA’s mandates affected, but now that the scope has widened to include so many more applications, and as a result a whole sub-industry is being affected as well. Obviously this has implications for OEMs, who put the engines and equipment together, but there’s also a large market for companies that distribute replacement parts directly to end-users, and they would need to make changes as well.

An added complication has been the implementation of state-wide regulations, such as California’s mandates issued by CARB (the California Air Resources Board). California is a very large market for many of these industries, but the CARB test methods vary considerably from the EPA’s and have to be met as well. In many cases this meant that once EPA approval had been gained, we needed to go through a separate third-party CARB-approved lab to get its sign-off as well.


5.      What has the response been from customers?

I must say that the reaction has been extremely positive. Because SGPPL is a leader in this industry, we were aware of the possible changes in regulations before many of our customers. We were able to get products ready for them ahead of time.

Many of the big OEMs already knew about it, of course, but a lot of customers for whom fuel lines aren’t a primary concern – those who are just buying 10 or 20 feet of tubing through a distributor to replace a tube on their lawnmower or their boat – haven’t necessarily been aware of the new rules. And so we’ve also been able to educate them on what they need to know, so they get the changes right first time.

As these regulations have started hitting, and as people have begun to settle in and realize what their obligations are in terms of compliance with the EPA and CARB directives, the response has really started to pick up.


6.      Do the existing solutions have any negative effects on a fuel-line’s performance?

Not at all.

The goal has always been to create a tube that is as close in look and feel as possible to the line it will supplement. This also made it easy for customers to transition.

We needed to create a clear version of the low-permeation range, so that you can still observe the liquid flow without affecting the barrier qualities. Obviously it’s a huge advantage when you’re troubleshooting an engine that won’t start, as in 99% of the cases the problem’s either that you’re not generating a spark or you’re not getting fuel into the carburetor.

As a general rule of thumb, barrier materials tend to be stiffer and harder, and we knew this could cause complications with tube flexibility. We were, however, only putting in a very thin layer of the barrier material – typically in the order of a few thousandths of an inch thick. The overall tube wall is much thicker in order to increase its flexibility and counter any stiffness – as well as to provide additional protection.


7.      How do you see the future of the fuel-line industry? Is low permeation going to be a requirement for all tubing going forward?

It’s hard to make long-term predictions, but I think we’re going to see an increased range of low-permeation tubes in the immediate future.  If the EPA continues to lower the permitted permeation numbers then the industry will need to react accordingly and make the necessary adjustments.

However, I do not think that these tubes are going to replace our existing lines – they’re a supplement and an extension to a product portfolio, not a substitution. A lot of people still can – and want to – use traditional tubing for applications that aren’t regulated – such as drainage or oil transfer – and there is no reason for them to make a change at this time.

At SGPPL, our low-permeation range comes out under our Tygon® brand with the designator “LP” to differentiate it from our traditional line. Those traditional tubes are going to continue to be offered as long as there is a market for them – it’s just that now there’s also a version that looks very much like them with a low-permeation barrier that meets the EPA and CARB requirements.