Understanding the Differences Between Fuel Hoses
Fuel hoses are not universal. Outside of the dimensional requirements, fuel hoses have requirements for permeation, pressure and the type of fuel they can carry. This can get even more confusing when you start looking at the lettering on the side of the hose.
The Society of Automotive Engineers (SAE) is an industry group that creates standards for the automotive industry. When it develops a standard, it applies to all manufacturers in hopes of reducing engineering and testing costs.
SAE has more than 16 active and inactive J30 standards for fuel and oil hoses. If you look at the side of a fuel, oil or emissions hose you will see the letters “SAE” followed by the number 30 (some will have a J first). Next in the sequence will be the letter “R” followed by a number. The number after the “R” refers to the section of the performance standard it pertains to. The criteria are typically permeation, chemical resistance, construction, temperature range and kink resistance. The higher the standards go, the more criteria that must be met.
“R” numbers in some cases do not determine the pressure rating for the hose. Hose manufacturers typically print on the hose if it is intended for use on fuel injection systems. Also, you should check with the manufacturer of the hose to see if it is compatible with fuels like E85 or biodiesel. NOTE: IF A HOSE DOESN’T HAVE A SAE J30- STANDARD ON THE SIDE, DON’T INSTALL IT IN A FUEL SYSTEM.
SAE 30R6 hoses are designed for low-pressure applications like carburetors. These can also be used as an emissions hose.
SAE 30R7 hoses are designed for fuel. These can go under the hood and are typically used for low-pressure applications.
SAE 30R9 hoses are designed for high-pressure applications like fuel injection and oil. These are designed to stand up to the environment under the hood.
SAE 30R10 includes hoses that are submerged in fuel. This type of hose is used inside the fuel tank and typically on the fuel pump module. This type of hose uses a special layer on the inside and outside to prevent the core layers from being saturated in fuel. But, don’t use it under the hood. R10 hoses can’t stand the heat.
SAE J30R12 includes low-permeation fuel feed and return hoses.
SAE J30R14T1 is the standard for ultra-low permeation properties. This type of hose is typically approved for use with leaded and unleaded gasoline, diesel, biodiesel, E85, methanol, ethanol and gasohol fuels. These are typically used for low-pressure applications.
The California Air Resources Board (C.A.R.B. or ARB) is a governmental body in the state of California charged with the task of improving air quality. Started in 1967, it regulates certain emissions related parts. Some fuel hoses have “CARB No.” printed on the side. This will be followed by a sequence of letters and numbers that indicate the hose can be used in the state of California.
EPA-Approved Fuel Hoses
If you see “EPA COMPLIANT” on the side of a fuel hose, it indicates that it is approved for use on marine and powersport applications by the Environmental Protection Agency (EPA). This type of fuel hose has low-permeation properties to ensure fuel will not pollute the waterways.
Do not replace long runs of hard line with flexible fuel hose. Even the best fuel injection, low-permeation fuel line will have some amount of fuel vapor loss. Also, road debris can damage these lines. Making this mistake is very dangerous, and it also can be difficult to seal the connection between the metal line and the hose that could be under 50 psi or more of pressure. Fuel hose length should be kept to a minimum, not only for safety, but for permeation and fuel loss purposes as well.
Do not use braided stainless steel lines or AN fittings unless they are SAE approved. You may have a customer who thinks racing-style braided stainless steel hoses are the ultimate solution for leaking fuel lines. They make sense for some racecars and rock crawlers, but for a daily driver, the “improved” lines could be a headache.
Most of these hoses don’t have to meet EPA, SAE and CARB standards for permeation. Some performance hoses also will not stand up well to higher ethanol content fuels. Teflon-coated and other similar hoses are designed to stand up to modern gasoline, but they can be twice as expensive as a hard line.
It is highly recommended when replacing fuel hoses that the clamps are also replaced. The first consideration is the size of the clamp. A clamp that is too large will not evenly seal the fuel hose to the line. The second consideration is the type of clamp. Worm gear clamps may work for low-pressure applications. But, for fuel injection applications, you need clamps that are specifically designed to handle the pressure and not damage the outer layer of the fuel hose.