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Safety & Technical Information
Physical Properties After Exposure to Oil Suction and Vacuum
Class Volume Tensile Strength Hose is constructed with high adhesion between the tube
Change Maximum Retained
and the carcass to prevent tube separation. Most hose is
Class A +25% 80% used for pressure service; however, some applications
(High Oil Resistance)
require the hose to resist collapse in suction and vacuum
Class B +65% 50% service. Such hose is subjected to crushing forces because
(Medium/High
Oil Resistance) the atmospheric pressure outside the hose is greater than
the internal pressure. The hose can collapse and restrict
Class C +100% 40%
(Medium Oil the flow unless the hose is constructed to resist these
Resistance) pressure differentials. The most common method of
preventing hose collapse is to build a helical member(s)
The above ARPM guideline does not imply compatibility (wire or thermoplastic) into the hose body. The size and
with all oil based fluids. There are many grades of rubber spacing of the helix depends on the size of the hose and
compounds that meet ARPM Class A oil resistance the pressure differential. In applications approaching a
requirements. Some compound grades will be fine for perfect vacuum, most of the plies of reinforcement are
multipurpose applications, while higher grades would be applied over the helix.
required for more rigorous applications. Suction hose must be specifically designed for the service
Oil resistant hoses for multipurpose service tend to be for which it is used. Each element—tube, reinforcement,
more economical than hoses specifically designed and size, spacing, and location of the helix—must be carefully
recommended for highly refined fuel service. These considered. While suction hose is generally used to convey
multipurpose hoses, even if they feature an ARPM liquids, vacuum hose carries air under a partial vacuum.
Class A tube, are not necessarily recommended for use Vacuum hose is reinforced to resist collapse and maintain
with highly refined fuels. Furthermore, many chemical its shape under rough handling and/or mechanical abuse.
resistance charts represent data developed from testing It does not require the heavy construction of suction hose
of a typical grade of compound used for that family of because the dry materials generally conveyed are much
fluids. For example, “nitrile” may show compatibility with lighter in weight than liquids and the vacuum is usually
gasoline, but the nitrile that was tested is likely the nitrile less than for normal suction service.
used in gasoline dispenser hose, as opposed to the nitrile
commonly used in multipurpose hose.
When selecting a hose for highly refined fuels such as
aviation fuel, biodiesel, diesel, ethanol, gasoline or
kerosene, be guided by the hose manufacturer’s recom-
mendation to use a hose designed and manufactured for
that specific application and/or fluid. Contact Parker for
further information.

408 Parker Industrial Hose Customer Service
866 810 HOSE (4673) 800 242 HOSE (4673)
Strongsville, OH South Gate, CA
Eastern USA Western USA
www.safehose.com
e-mail: indhose@parker.com