General Information
Rubber hose is used to convey petroleum products both in the crude and refined stages. The aromatic
content of refined gasoline is often adjusted to control the octane rating. The presence of aromatic
hydrocarbons in this fuel generally has a greater effect on rubber components than do aliphatic
hydrocarbons. Aromatic materials in contact with rubber tend to soften it and reduce its physical
properties. For long-lasting service, the buyer of gasoline hose should inform the hose manufacturer of
the aromatic content of the fuel to be handled so that the proper tube compound can be recommended
for the specific application.
The effects of oil on rubber depend on a number of factors that include the type of rubber compound
the composition of the oil, the temperature and time of exposure. Rubber compounds can be classified
as to their degree of oil resistance based on their physical properties after exposure to a standard test
fluid. In this RMA classification, the rubber samples are immersed in IRM 903 oil at 212˚F (100˚C) for 70
hours. (See ASTM Method D-471 for a detailed description of the oil and the testing procedure.) As a
guide to the user of hose in contact with oil, the oil resistance classes and a corresponding description
are listed.
(
Reprinted From RMA Hose
Handbook IP-2 2003 Edition)
Physical Properties After Exposure to Oil
Volume Change Maximum
Tensile Strength Retained
Class A (High Oil Resistance)
+25%
80%
Class B (Medium Oil Resistance)
+65%
50%
Class C (Limited Oil Resistance)
+100%
40%
RMA Oil and Gasoline Resistance
345
Appendix
C
Air & Multipurpose
General Purpose
Heavy Duty
Push-on
Chemical Transfer
Cleaning Equipment
Food
Transfer
Washdown
Marine
Material Handling
Abrasives
Bulk Transfer
Cement & Concrete
Mining
Petroleum
Aircraft Fueling
Dispensing
Dock
Transfer
Spray
Steam
Vacuum
LPG Delivery
Water
Discharge
Suction & Discharge
Washdown
Welding
Coupling Systems
Equipment
Appendix