Page 420 - Cat4800-Oct2011

406 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
Safety & Technical Information
Age Control of Hose (Shelf Life)
Te Parker warranty takes precedence over guidelines
established by other industry organizations regarding
the recommended shelf life of industrial hose. To achieve
maximum shelf life, employ proper storage and handling
practices and techniques, such as:
• Storage in the original shipping container such as
a box, coil, or reel. Hose stored on a reel or in a coil
should have its plastic wrapping kept intact.
• Storage in temperatures of 100°F (38°C) or less.
• Avoidance of ozone (electrical discharges or felds),
water, extreme humidity, corrosive chemicals and
ultraviolet radiation (direct sunlight).
• Use on a frst-in, frst-out (FIFO) basis determined by
the manufacturing date on the hose.
For further information pertaining to age control of
hose, contact Parker or refer to the current ARPM Hose
Handbook, IP-2.
Electrical Properties
of Rubber Hose
Electrical Conductivity
Industrial hoses generally fall into three categories:
conductive, nonconductive, or somewhere in-between.
Because of its unique properties, it is possible for rubber
to be nonconductive at low voltage and conductive at
high voltage. When using a hose in an application that
has electrical resistance requirements (low electrical
resistance for conductive applications or high electrical
resistance for nonconductive applications), always select
a hose that is specifcally designed to meet the specifc
need. Since conductivity or nonconductivity is not a
consideration for many applications, electrical resistance
ratings do not exist for many hoses.
Conductive Hose
Static electricity is generated by the fow of material
(even some liquids) through a hose. As the material fows,
molecules collide and generate friction, which creates
minute amounts of electrical charge (excess electrons).
Te charge accumulates potential energy at the delivery
end of the hose (coupling/nozzle). Te amount of charge
increases with material volume and linear velocity,
coarseness of the material, and length of the hose. If not
properly grounded, the accumulated charge (potential
energy) will seek its own ground. Te charge will be
attracted to external materials in proximity (such as a steel
storage container); if not properly grounded, the electrons
may arc (jump) to the external material, igniting volatile
materials in the hose, or in proximity to the hose.
Electrically conductive wires and conductive rubber
components are used in hose to prevent static electricity
build-up and discharge as a spark. Electrical engineers
difer in opinion on the efects of static electricity and
the means of dissipating it. In handling gasoline and
other petroleum-based liquids, recognized national
associations and companies have conficting opinions
on the need for conductive hoses. Until a consensus is
reached among all associations, laboratories and users,
and a standard practice is established, it is essential that
the user determine the need for static bonded hose based
on (a) the intended use of the hose, (b) instructions from
the company’s safety division, (c) the insurer, and (d) the
laws of the localities and states in which the hose will be
used.
Some types of hose include a helical or static wire(s). Tis
wire can be used for electrical continuity provided that
proper contact is made and maintained between it and
the hose couplings.
Nonconductive Hose
Nonconductive hose constructions are those that
resist the fow of electrical current. In some specifc
applications, especially around high voltage electrical
lines, it is imperative for safety that the hose be
nonconductive. Unless the hose is designed particularly to
be nonconductive and is so branded, do not conclude that
it is nonconductive. Many black rubber compounds are
inherently and inadvertently conductive. Nonconductive
hose is usually made to a qualifying standard that requires
it to be tested to verify the desired electrical properties.
Te hose is frequently (but not necessarily) non-black in
color and clearly branded to indicate it is designed for
nonconductive applications.
NOTE 1: Parker industrial hose generally uses the non-
conduc­tivity standard originally developed by Alcoa
Aluminum: A minimum resistance of one megaohm per
inch at 1,000 volts D.C.
NOTE 2: SAE has a separate standard for nonconduc­tiv-
ity for high pressure hydraulic applications. Part of the
standard requires that nonconductive hose feature an
orange cover.
NOTE 3: Nonconductive hoses contain little/no con-
ductive rubber compounds, static wires, helical wires,
or wire reinforcement. Terefore, a nonconductive hose
would not be recommended for an application requiring
an “anti-static/static dissipating/conductive” hose.
WARNING! Unless a hose is described as, or
specifcally and clearly branded to be conducting or
nonconducting, assume that the electrical properties
are uncontrolled.