SYSTEM TYPE
CODE LEVEL
18/15 or better
Low to medium pressure -
electrohydraulic controls
17/14 or better
Systems with servo or
proportional control valves
17/14 or better
controlled
15/12 or better
Hydraulic fluid power equipment is rated according
to maximum pressure. Generally low pressure is 0 to
4.1 MPa (0 to 600 psi), medium pressure to 20.7 MPa
Results of microscopic particle count in accordance
with SAE ARP598 are reported as the number of
particles per milliliter greater than indicated
sizes as ordinates on a graph where particle size in
microns is the abscissa. Segments of the ordinate
are assigned code levels and the code level for
particle sizes greater than 15 microns is reported
as the numerator, and the code level for particle
sizes greater than 5 microns is reported as the
denominator in the pair of range numbers in the ISO
(International Organization for Standardization)
J1165. Higher code levels indicate higher particle
counts per millimeter. Example: 15/12 means a code
level of 15 for particles greater than 5 microns and
a code level of 12 for particles greater than 15
microns. Filter manufacturing firms can be the
source of information regarding determination of
portable kits for more general detection of
contamination.
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Extreme care shall be taken during assembly to avoid the entrance of
abrasives, dirt, metal chips, and other foreign materials into the
hydraulic system through open ends of piping, tubing, and ports of the
components. The Contractor shall submit a detailed cleaning and flushing
the system procedure for approval in accordance with paragraph SUBMITTALS.
The procedure shall include a detailed description of the equipment,
materials, formulations of cleaning agents, solution temperatures, duration
of each phase of the cleaning operation, method of removal of cleaning
agents, and method of drying after cleaning. The procedure shall clean the
system of particles so that the contamination level is below [_____] in
accordance with SAE J1165. The Contractor shall take three 500 milliliter
samples at approved locations according to ISO 4021. Particle counting on
each sample shall be performed in accordance with SAE ARP598 by an approved
independent test laboratory. Water content of each sample shall be below
200 ppm. If any sample does not comply with the permissible contamination
limits, the system shall be recleaned and reinspected. When flushing is
completed, the system shall be drained and then filled with the specified
hydraulic fluid.
SECTION 15010A
Page 35