[Code of Federal Regulations]
[Title 7, Volume 11]
[Revised as of January 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 7CFR1755.900]
[Page 708-729]
TITLE 7--AGRICULTURE
CHAPTER XVII--RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE
PART 1755--TELECOMMUNICATIONS STANDARDS AND SPECIFICATIONS FOR MATERIALS, EQUIPMENT AND CONSTRUCTION--Table of Contents
Sec. 1755.900 RUS specification for filled fiber optic cables.
(a) Scope. (1) This section covers the requirement for filled fiber
optic cables intended for aerial installation either by attachment to a
support strand or by an integrated self-supporting arrangement, for
underground application by placement in a duct, or for buried
installations either by trenching or by direct plowing.
(i) The optical waveguides are glass fibers having directly-applied
protective coatings, and are called ``fibers'', herein. These fibers may
be assembled in either loose fiber bundles with a protective core tube,
encased in several protective buffer tubes, or in tight buffer tubes.
(ii) Fillers, strength members, core wraps, and bedding tapes may
complete the cable core.
(iii) The core or buffer tubes containing the fibers and the
interstices between the buffer tubes, fillers, and strength members in
the core structure are filled with a suitable material to exclude water.
(iv) The cable structure is completed by an extruded overall plastic
jacket. This jacket may have strength members embedded in it, in some
designs.
(v) Buried installation requires an armor under the outer jacket.
(vi) For self-supporting cable the outer jacket may be extruded over
the support messenger and cable core.
(2) The cable is fully color coded so that each fiber is
distinguishable from every other fiber. A basic color scheme of twenty-
four colors allows individual fiber identification. Colored tubes,
binders, threads, stripings, or markings provide fiber group
identification.
(3) Cable manufactured to this section must demonstrate compliance
with the qualification testing requirements to ensure satisfactory end-
use performance characteristics for the intended applications.
(4) Optical cable designs not specifically addressed by this section
may be allowed if accepted by RUS. Justification for acceptance of a
modified design must be provided to substantiate product utility and
long term stability and endurance.
(5) All cables sold to RUS borrowers for projects involving RUS loan
funds under this section must be accepted by RUS Technical Standards
Committee ``A'' (Telephone). For cables manufactured to the
specification of this section, all design changes to an accepted design
must be submitted for acceptance. RUS will be the sole authority on what
constitutes a design change.
(6) The American National Standard Institute/Institute of Electrical
and Electronics Engineers, Inc (ANSI/IEEE), 1993 National Electrical
Safety Code (NESC) referenced in this section is incorporated by
reference by RUS. This incorporation by reference was approved by the
Director of the Federal Register in accordance with 5 U.S.C. 552(a) and
1 CFR part 51. Copies of ANSI/IEEE 1993 NESC are available for
inspection during normal business hours at RUS, room 2845, U.S.
Department of Agriculture, Washington, DC 20250-1500 or at the Office of
the Federal Register, 800 North Capitol Street, NW., suite 700,
Washington, DC. Copies are available from IEEE Service Center, 445 Hoes
Lane, Piscataway, NJ 08854, telephone number 1 (800) 678-4333.
(7) American Society for Testing and Materials Specifications (ASTM)
A 640-91, Standard Specification for Zinc-Coated Steel Strand for
Messenger Support of Figure 8 Cable; ASTM B 736-92a, Standard
Specification for Aluminum, Aluminum Alloy, and Aluminum-Clad Steel
Cable Shielding Stock; ASTM D 1238-90b, Standard Test
[[Page 709]]
Method for Flow Rates of Thermoplastics by Extrusion Plastometer; ASTM D
1248-84 (1989), Standard Specification for Polyethylene Plastic Molding
and Extrusion Materials, ASTM D 1535-89, Standard Test Method for
Specifying Color by the Munsell System; ASTM D 3349-86, Standard Test
Method for Absorption Coefficient of Carbon Black Pigmented Ethylene
Plastic; ASTM D 4565-90a, Standard Test Methods for Physical and
Environmental Performance Properties of Insulations and Jackets for
Telecommunications Wire and Cable; ASTM D 4566-90, Standard Test Methods
for Electrical Performance Properties of Insulations and Jackets for
Telecommunications Wire and Cable; ASTM D 4568-86, Standard Test Methods
for Evaluating Compatibility Between Cable Filling and Flooding
Compounds and Polyolefin Cable Materials; and ASTM E 29-90, Standard
Practice for Using Significant Digits in Test Data to Determine
Conformance with Specifications, referenced in this section are
incorporated by reference by RUS. These incorporations by references
were approved by the Director of the Federal Register in accordance with
5 U.S.C. 552(a) and 1 CFR part 51. Copies of ASTM standards are
available for inspection during normal business hours at RUS, room 2845,
U.S. Department of Agriculture, Washington, DC 20250-1500 or at the
Office of the Federal Register, 800 North Capitol Street, NW., suite
700, Washington, DC. Copies are available from ASTM, 1916 Race Street,
Philadelphia, Pennsylvania 19103-1187, telephone number (215) 299-5585.
(8) Electronic Industries Association Standards (EIA)-455-20,
Measurement of Change in Optical Transmittance; EIA-455-41, Compressive
Loading Resistance of Fiber Optic Cables; EIA-455-86, Fiber Optic Cable
Jacket Shrinkage; EIA-455-89A, Fiber Optic Cable Jacket Elongation And
Tensile Strength; and EIA-455-174, Mode Field Diameter of Single-Mode
Optical Fiber by Knife-Edge Scanning in the Far Field, referenced in
this section are incorporated by reference by RUS. These incorporations
by references were approved by the Director of the Federal Register in
accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of EIA
standards are available for inspection during normal business hours at
RUS, room 2845, U.S. Department of Agriculture, Washington, DC 20250-
1500 or at the Office of the Federal Register, 800 North Capitol Street,
NW., suite 700, Washington, DC. Copies are available from Global
Engineering Documents, 15 Inverness Way East, Englewood, CO 80112,
telephone number (303) 792-2181.
(9) Electronic Industries Association/Telecommunications Industries
Association Standards (EIA/TIA)-455-25A, Repeated Impact Testing of
Fiber Optic Cables and Cable Assemblies; EIA/TIA-455-30B, Frequency
Domain Measurement of Multimode Optical Fiber Information Transmission
Capacity; EIA/TIA-455-31B, Fiber Tensile Proof Test Method; EIA/TIA-455-
37A, Low or High Temperature Bend Test for Fiber Optic Cable; EIA/TIA-
455-45B, Method for Measuring Optical Fiber Geometry Using a Laboratory
Microscope; EIA/TIA-455-46A, Spectral Attenuation Measurement for Long-
Length, Graded-Index Optical Fibers; EIA/TIA-455-48B, Measurement of
Optical Fiber Cladding Diameter Using Laser-Based Instruments; EIA/TIA-
455-51A, Pulse Distortion Measurement of Multimode Glass Optical Fiber
Information Transmission Capacity; EIA/TIA-455-53A, Attenuation by
Substitution Measurement for Multimode Graded-Index Optical Fibers or
Fiber Assemblies Used in Long Length Communications Systems; EIA/TIA-
455-55B, End-View Methods for Measuring Coating and Buffer Geometry of
Optical Fibers; EIA/TIA-455-58A, Core Diameter Measurement of Graded-
Index Optical Fibers; EIA/TIA-455-59, Measurement of Fiber Point Defects
Using an OTDR; EIA/TIA-455-61, Measurement of Fiber or Cable Attenuation
Using an OTDR; EIA/TIA-455-78A, Spectral-Attenuation Cutback Measurement
for Single-Mode Optical Fibers; EIA/TIA-455-81A, Compound Flow (Drip)
Test for Filled Fiber Optic Cable; EIA/TIA-455-82B, Fluid Penetration
Test for Fluid-Blocked Fiber Optic Cable; EIA/TIA-455-85A, Fiber Optic
Cable Twist Test; EIA/TIA-455-104A, Fiber Optic Cable Cyclic Flexing
Test; EIA/TIA-455-164A, Single-Mode Fiber,
[[Page 710]]
Measurement of Mode Field Diameter by Far-Field Scanning; EIA/TIA-455-
165A, Mode Field Diameter Measurement Near Field Scanning Technique;
EIA/TIA-455-167A, Mode Field Diameter, Variable Aperture in the Far
Field; EIA/TIA-455-168A, Chromatic Dispersion Measurement of Multimode
Graded-Index and Single-Mode Optical Fibers by Spectral Group Delay
Measurement in the Time Domain; EIA/TIA-455-169A, Chromatic Dispersion
Measurement of Single-Mode Optical Fibers by the Phase-Shift Method;
EIA/TIA-455-170, Cable Cutoff Wavelength of Single-Mode Fiber by
Transmitted Power; EIA/TIA-455-173, Coating Geometry Measurement for
Optical Fiber Side-View Method; EIA/TIA-455-175A, Chromatic Dispersion
Measurement of Single-Mode Optical Fibers by the Differential Phase
Shift Method; EIA/TIA-455-176, Method for Measuring Optical Fiber Cross-
Sectional Geometry by Automated Grey-Scale Analysis; EIA/TIA-455-177A,
Numerical Aperture Measurement of Graded-Index Optical Fibers; EIA/TIA-
455-178, Measurements of Strip Force Required for Mechanically Removing
Coatings from Optical Fibers; and EIA/TIA-598, Color Coding of Fiber
Optic Cables, referenced in this section are incorporated by reference
by RUS. These incorporations by references were approved by the Director
of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR
part 51. Copies of EIA/TIA standards are available for inspection during
normal business hours at RUS, room 2845, U.S. Department of Agriculture,
Washington, DC 20250-1500 or at the Office of the Federal Register, 800
North Capitol Street, NW., suite 700, Washington, DC. Copies are
available from Global Engineering Documents, 15 Inverness Way East,
Englewood, CO 80112, telephone number (303) 792-2181.
(10) RUS intends that the optical fibers contained in the cables
manufactured in accordance with this section have characteristics that
will allow signals, having a range of wavelengths, to be carried
simultaneously.
(b) Optical fibers. (1) The solid glass optical fibers must consist
of a cylindrical core and cladding covered by either an ultraviolet-
cured acrylate or other suitable coating.
(2) The optical fiber types must be one of the following:
(i) Dispersion-unshifted single mode fiber EIA Class IVa;
(ii) Dispersion-shifted single mode fiber EIA Class IVb;
(iii) 50/125 micrometer multimode fiber EIA Class Ia; or
(iv) 62.5/125 micrometer multimode fiber EIA Class Ia.
(3) The dispersion-unshifted single mode fiber core must have either
a matched or depressed clad step refractive index profile with a mode-
field diameter of 9.01.0 micrometers when measured at 1300
nanometers and 10.5+1.0 micrometers/-1.5 micrometers when measured at
1550 nanometers in accordance with any one of the following test
methods:
(i) EIA/TIA-455-164A;
(ii) EIA/TIA-455-165A;
(iii) EIA/TIA-455-167A; or
(iv) EIA-455-174.
(4) The dispersion-shifted single mode fiber core must have either a
segmented core design or depressed clad step refractive index profile
with a mode-field diameter of 7.5+1.5 micrometers/-1.3 micrometers when
measured at 1550 nanometers in accordance with any one of the test
procedures specified in paragraph (b)(3) of this section.
(5) The core clad off-set of the dispersion-unshifted and
dispersion-shifted single mode fibers must not be greater than 1.0
micrometer when measured in accordance with either EIA/TIA-455-45B or
EIA/TIA-455-176.
(6) The multimode fiber cores must have graded (parabolic)
refractive index profiles with core diameters of 50.03.0
micrometers or 62.53.0 micrometers when measured in
accordance with either EIA/TIA-455-58A, or EIA/TIA-455-176.
(7) The core noncircularity of multimode fibers must not exceed 6
percent when measured in accordance with either EIA/TIA-455-45B or EIA/
TIA-455-176.
(8) The outside diameter of the glass fiber for both single mode and
multimode fibers must be 1252.0 micrometers when measured in
accordance with any one of the following test methods:
(i) EIA/TIA-455-45B;
(ii) EIA/TIA-455-176; or
[[Page 711]]
(iii) EIA/TIA-455-48B, Methods A or B.
(9) The outside diameter of the glass fiber must be nominally
concentric with the fiber core as is consistent with the best commercial
practice.
(10) The individual fibers must be proof tested at a minimum tensile
stress of 0.35 gigapascal for approximately one second when measured in
accordance with EIA/TIA-455-31B.
(11) Factory splices of fibers are allowed provided that prior
acceptance from RUS is obtained for the splice technique, that all
splices are documented and reported to the customer and that the spliced
fiber meets all requirements of this section.
(12) The optical fiber must be coated with a suitable material to
preserve the intrinsic strength of the glass having an outside diameter
of 25015 micrometers when measured in accordance with either
EIA/TIA-455-55B or EIA/TIA-455-173.
(13) The maximum force required to remove 25 millimeters of
protective fiber coating must not exceed 13 newtons when measured in
accordance with EIA/TIA-455-178.
(14) All optical fibers in any single length of cable must be of the
same type.
(c) Buffer/coating. (1) The optical fibers contained in a tube
buffer (loose tube), an inner jacket (unit core), a channel or otherwise
loosely packaged must have a clearance between the fibers and the inside
of the container sufficient to allow for thermal expansions without
constraining the fibers. The protective container must be manufactured
from a material having a coefficient of friction sufficiently low to
allow the fibers free movement.
(2) Optical fibers covered in near contact with an extrusion (tight
tube) must have an intermediate soft buffer to allow for thermal
expansions and minor pressures.
(3) All protective coverings in any single length of cable must be
continuous and be of the same material except at splice locations.
(4) The protective coverings must be free from holes, splits,
blisters, and other imperfections and must be as smooth and concentric
as is consistent with the best commercial practice.
(5) Repairs to the fiber coatings are not allowed except at splice
locations.
(6) Both loose tube and tight tube coverings of each color and other
fiber package types removed from the finished cable must meet the
following shrinkback and cold bend performance requirements. The fibers
may be left in the tubes.
(i) Shrinkback. Testing must be conducted in accordance with ASTM D
4565-90a, paragraph 14.1, using a talc bed at a temperature of 95
deg.C. Shrinkback must not exceed 5 percent of the original 150
millimeter length of the specimen. The total shrinkage of the specimen
must be measured.
(ii) Cold bend. Testing must be conducted on at least one tube from
each color in the cable. Stabilize the specimen to -201
deg.C for a minimum of four hours. While holding the specimen and
mandrel at the test temperature, wrap the tube in a tight helix ten
times around a mandrel with a diameter not greater than five times the
tube diameter. The tube must show no evidence of cracking when observed
with normal or corrected-to-normal vision.
Note: Channel cores and similar slotted single component core
designs need not be tested for cold bend.
(d) Fiber and buffer tube identification. (1) The colors designated
for identification of loose buffer tubes, tight tube buffer fibers and
individual fibers in multifiber tubes, slots or bundles are shown in the
following table:
------------------------------------------------------------------------
Buffer tube and fiber No. Color
------------------------------------------------------------------------
1................................ Blue.
2................................ Orange.
3................................ Green.
4................................ Brown.
5................................ Slate.
6................................ White.
7................................ Red.
8................................ Black.
9................................ Yellow.
10............................... Violet.
11............................... Rose.
12............................... Aqua.
13............................... Blue/Black Tracer.
14............................... Orange/Black Tracer.
15............................... Green/Black Tracer.
16............................... Brown/Black Tracer.
17............................... Slate/Black Tracer.
18............................... White/Black Tracer.
19............................... Red/Black Tracer.
20............................... Black/Yellow Tracer.
21............................... Yellow/Black Tracer.
22............................... Violet/Black Tracer.
23............................... Rose/Black Tracer.
24............................... Aqua/Black Tracer.
------------------------------------------------------------------------
[[Page 712]]
(2) Standards of color. Except for the aqua color, the colors of
fibers and tubes supplied in accordance with this section are specified
in terms of the Munsell Color System (ASTM D 1535-89) and must comply
with the color limits as defined in EIA/TIA-598. (A visual color
standard meeting these requirements and entitled ``Munsell Color Charts
for Color Coding,'' may be obtained from the Munsell Color Company,
Inc., 2441 North Calvert Street, Baltimore, Maryland 21218. The latest
edition of the color standard should be used.)
(i) The aqua color limits using the Munsell Color System must be as
follows:
Munsell Notation
------------------------------------------------------------------------
Symbol Aqua color
------------------------------------------------------------------------
Centroid................................... 10BG 7/6
H++........................................ 5B 7/6
H--........................................ 5BG 7/6
V++........................................ 10BG 8/4
V--........................................ 10BG 6/6
C++........................................ None
C--........................................ 10BG 7/4
------------------------------------------------------------------------
(ii) Other coloring schemes used for providing identification of
buffer tubes and optical fibers which deviate from the requirements of
paragraph (d)(1) of this section will not be accepted by RUS.
(e) Strength members. (1) Strength members must be an integral part
of the cable construction, but are not considered part of the support
messenger for self-supporting optical cable.
(2) The combined strength of all the strength members must be
sufficient to support the stress of installation and to protect the
cable in service.
(3) Strength members may be incorporated into the core as a central
support member or filler, as fillers between the fiber packages, as an
annular serving over the core, as an annular serving over the
intermediate jacket, embedded in the outer jacket or as a combination of
any of these methods.
(4) The central support member or filler must contain no more than
one splice per kilometer of cable. Individual fillers placed between the
fiber packages and placed as annular servings over the core must contain
no more than one splice per kilometer of cable. Cable sections having
central member or filler splices must meet the same physical
requirements as unspliced cable sections.
(5) Strength member materials and splicing techniques must be
accepted by RUS prior to their use.
(6) In each length of completed cable having a metallic central
member, the dielectric strength between the armor and the metallic
center member must withstand at least 15 kilovolts direct current for 3
seconds.
(f) Forming the cable core. (1) Protected fibers must be assembled
with the optional central support member, fillers and strength members
in such a way as to form a cylindrical group.
(2) The standard cylindrical group or core designs shall consist of
4, 6, 8, 10, 12, 16, 18, 20, or 24 fibers. Cylindrical groups or core
designs larger than the sizes shown above must meet all the requirements
of this section.
(3) When threads or tapes are used as core binders, they must be
colored either white or natural and must be a nonhygroscopic and
nonwicking dielectric material.
(4) When threads or tapes are used as unit binders to define optical
fiber units in loose tube, tight tube, slotted, or bundled cored
designs, they must be colored in accordance with the table listed below
and must be a nonhygroscopic and nonwicking dielectric material or be
rendered such by the filling compound. The colors of the binders must be
in accordance with paragraphs (d)(2) introductory text and (d)(2)(i) of
this section.
------------------------------------------------------------------------
Unit No. Binder color
------------------------------------------------------------------------
1................................ Blue.
2................................ Orange.
3................................ Green.
4................................ Brown.
5................................ Slate.
6................................ White.
7................................ Red.
8................................ Black.
9................................ Yellow.
10............................... Violet.
11............................... Rose.
12............................... Aqua.
13............................... Blue-Black.
14............................... Orange-Black.
15............................... Green-Black.
16............................... Brown-Black.
17............................... Slate-Black.
18............................... White-Black.
19............................... Red-Black.
20............................... Black-Black-Yellow.
21............................... Yellow-Yellow-Black.
22............................... Violet-Black.
[[Page 713]]
23............................... Rose-Black.
24............................... Aqua-Black.
------------------------------------------------------------------------
(g) Filling compound. (1) To prevent the ingress of water into the
core, a filling compound must be applied into the interior of the loose
fiber tubes and into the interstices of the core. When a core wrap is
used, the filling compound must also be applied to the core wrap, over
the core wrap and between the core wrap and inner jacket when required.
(2) The materials must be homogeneous and uniformly mixed; free from
dirt, metallic particles and other foreign matter; easily removed;
nontoxic and present no dermal hazards.
(3) The individual cable manufacturer must satisfy RUS that the
filling compound selected for use is suitable for its intended
application. The filling compound must be compatible with the cable
components when tested in accordance with ASTM D 4568-86 at a
temperature of 80 deg.C.
(h) Core wrap (optional). (1) At the option of the manufacturer, one
or more layers of nonhygroscopic and nonwicking dielectric material may
be applied over the core.
(2) The core wrap(s) can be used to provide a heat barrier to
prevent deformation or adhesion between the fiber tubes or can be used
to contain the core.
(3) When core wraps are used, sufficient filling compound must be
applied to the core wraps so that voids or air spaces existing between
the core wraps and between the core the inner side of the core wrap are
minimized.
(i) Inner jacket. (1) Inner jackets may be applied directly over the
core or over the strength members.
(i) For armored cable an inner jacket is optional but recommended.
The inner jacket may absorb stresses in the cable core that may be
introduced by armor application or by armored cable installation.
(ii) For unarmored cable an inner jacket is optional.
(2) The inner jacket material and test requirements must be as for
the outer jacket material per paragraphs (m)(3) introductory text
through (m)(3)(v) of this section, except that either black or natural
polyethylene may be used. In the case of natural polyethylene, the
requirements for absorption coefficient and the inclusion of furnace
black are waived.
(j) Flooding compound. (1) Sufficient flooding compound must be
applied between the inner jacket and armor and between the armor and
outer jacket so that voids and air spaces in these areas are minimized.
The use of floodant between the armor and outer jacket is not required
when uniform bonding, per paragraph (k)(10) of this section, is achieved
between the plastic-clad armor and the outer jacket.
(2) The flooding compound must be compatible with the jacket when
tested in accordance with ASTM D 4568-86 at a temperature of 80 deg.C.
The floodant must exhibit adhesive properties sufficient to prevent
jacket slip when tested in accordance with the requirements of appendix
A, paragraph (III)(3), of this section.
(3) The individual cable manufacturer must satisfy RUS that the
flooding compound selected for use is acceptable for the application.
(4) In lieu of a flooding compound, water blocking tapes may be
applied between the inner jacket and armor and between the armor and
outer jacket to prevent water migration. The use of the water blocking
tape between the armor and outer jacket is not required when uniform
bonding, per paragraph (k)(10) of this section, is achieved between the
plastic-clad armor and the outer jacket.
(k) Armor. (1) A steel armor, plastic coated on both sides, is
required for direct buried cable manufactured under the provisions of
this section. An armor is optional for duct and aerial cable as required
by the purchaser. The plastic coated steel armor must be applied
longitudinally directly over the core wrap or the intermediate jacket
and have a minimum overlap of 3.0 millimeters.
(2) The uncoated steel tape must be electrolytic chrome coated steel
(ECCS) with a thickness of 0.155 0.015 millimeters.
(3) The reduction in thickness of the armoring material due to the
[[Page 714]]
corrugating or to the application process must be kept to a minimum and
must not exceed 10 percent at any spot.
(4) The armor of each length of cable must be electrically
continuous with no more than one joint or splice allowed per kilometer
of cable. This requirement does not apply to a joint or splice made in
the raw material by the raw material manufacturer.
(5) The breaking strength of any section of an armor tape,
containing a factory splice joint, must not be less than 80 percent of
the breaking strength of an adjacent section of the armor of equal
length without a joint.
(6) For cables containing no floodant over the armor, the overlap
portions of the armor tape must be bonded in cables having a flat,
noncorrugated armor to meet the requirements of paragraphs (q)(1)
through (q)(7)(ii) of this section. If the tape is corrugated, the
overlap portions of the armor tape must be sufficiently bonded and the
corrugations must be sufficiently in register to meet the requirements
of paragraphs (q)(1) through (q)(7)(ii) of this section.
(7) The armor tape must be so applied as to enable the cable to pass
the bend test as specified in paragraph (q)(1) of this section.
(8) The protective coating on the steel armor must meet the Bonding-
to-Metal, Heat Sealability, Lap-Shear and Moisture Resistance
requirements of Type I, Class 2 coated metals in accordance with ASTM B
736-92a.
(9) The ability of the plastic-clad metal to resist the flooding
compound must be determined as required by ASTM D 4568-86 using a one
meter length of coated steel which must be aged for 7 days at
681 deg.C. There must be no delamination of the coating
from the steel at the conclusion of the test.
(10) When the jacket is bonded to the plastic coated armor, the bond
between the plastic coated armor and the outer jacket must not be less
than 525 newtons per meter over at least 90 percent of the cable
circumference when tested in accordance with ASTM D 4565-90a. For cables
with strength members embedded in the jacket, and residing directly over
the armor, the area of the armor directly under the strength member is
excluded from the 90 percent calculation.
(l) Optional support messenger (aerial cable). (1) When a self-
supporting aerial cable containing an integrated support messenger is
supplied, the support messenger must comply with the requirements
specified in paragraphs (l)(2) introductory text through (l)(6) of this
section.
(2) The fully flooded, stranded support messenger must be 6.35
millimeters diameter, 7 wire, extra high strength grade, Class A
galvanized steel strand conforming to ASTM A 640-91 with exceptions and
additional provisions as follows:
(i) The maximum lay of the individual wires of the strand must be
140 millimeters.
(ii) Any section of a completed strand containing a joint must have
minimum tensile strength and elongation of 29,500 newtons and 3.5
percent, respectively, when tested in accordance with the procedures
specified ASTM A 640-91.
(iii) The individual wires from a completed strand which contain
joints must not fracture when tested according to the ``Ductility of
Steel'' procedures specified in ASTM A 640-91 except that the mandrel
diameter must be equal to 5 times the nominal diameter of the individual
wires.
(3) The support strand must be completely covered with a corrosion
protective floodant. The floodant must be homogeneous and uniformly
mixed.
(4) The floodant must be nontoxic and present no dermal hazard.
(5) The floodant must be free from dirt, metallic particles, and
other foreign matter that may interfere with the performance of the
cable.
(6) The floodant must be compatible with the polyethylene outer
jacket and must be acceptable to RUS.
(7) Other methods of providing self-supporting cable specifically
not addressed in this section may be allowed if accepted by RUS.
Justification for acceptance of a modified design must be provided to
substantiate product utility and long term stability and endurance.
(m) Outer jacket. (1) The outer jacket must provide the cable with a
tough, flexible, protective covering which can
[[Page 715]]
withstand exposure to sunlight, to atmosphere temperatures and to
stresses reasonably expected in normal installation and service.
(2) The jacket must be free from holes, splits, blisters, or other
imperfections and shall be as smooth and concentric as is consistent
with the best commercial practice.
(3) The raw material used for the outer jacket must be one of the
five types listed in paragraphs (m)(3)(i) through (m)(3)(v) of this
section. The raw material must contain an antioxidant to provide long
term stabilization and the materials must contain a 2.600.25
percent concentration of furnace black to provide ultraviolet shielding.
Both the antioxidant and furnace black must be compounded into the
material by the raw material supplier.
(i) Low density, high molecular weight polyethylene (LDHMW) must
conform to the requirements of ASTM D 1248-84(1989), Type I, Class C,
Category 4 or 5, Grade J3.
(ii) Low density, high molecular weight ethylene copolymer (LDHMW)
must conform to the requirements of ASTM D 1248-84(1989), Type I, Class
C, Category 4 or 5, Grade J3.
(iii) Linear low density, high molecular weight polyethylene
(LLDHMW) must conform to the requirements of ASTM D 1248-84(1989), Type
I, Class C, Category 4 or 5, Grade J3.
(iv) High density polyethylene (HD) must conform to the requirements
of ASTM D 1248-84(1989), Type III, Class C, Category 4 or 5, Grade J4.
(v) Medium density polyethylene (MD) must conform to the
requirements of ASTM D 1248-84(1989), Type II, Class C, Category 4 or 5,
Grade J4.
(vi) Particle size of the carbon selected for use must not average
greater than 20 nanometers.
(vii) Absorption coefficient must be a minimum of 400 in accordance
with the procedures of ASTM D 3349-86.
(4) The outer jacketing material removed from or tested on the cable
must be capable of meeting the following performance requirements:
------------------------------------------------------------------------
LLDHMW,
Property ethylene LDHMW HD or MD
copolymer polyethylene polyethylene
------------------------------------------------------------------------
Melt Flow Rate:
Percent increase from raw ........... 50 50
material, Maximum.........
<0.41 (Initial Melt Index). 100
0.41-2.00 (Initial Melt 50 ............
Index)....................
Tensile Strength:
Minimum, Megapascals....... 12 12 16.5
Ultimate Elongation:
Minimum, Percent........... 400 400 300
Environmental Stress Cracking:
Maximum, Failures.......... 0/10 2/10 2/10
Shrinkback:
Maximum, Percent........... 5 5 5
Impact:
Maximum, Failures.......... 2/10 2/10 2/10
------------------------------------------------------------------------
(5) Testing procedures. The procedures for testing jacket specimens
for compliance with paragraph (m)(4) of this section must be as follows:
(i) Melt flow rate. The melt flow rate must be determined by ASTM D
1238-90b, Condition E. Jacketing material must be free from flooding and
filling compound.
(ii) Tensile strength and ultimate elongation. Test in accordance
with EIA-455-89A, using a jaw separation speed of 500 millimeters per
minute for low density material and 50 millimeters per minute for high
and medium density materials.
(iii) Environmental stress cracking. Test in accordance with ASTM D
4565-90a.
(iv) Shrinkback. Test in accordance with the procedures specified in
EIA-455-86 using a temperature of 100 1 deg.C for a 4 hour
period for low density material and a test temperature of 115
1 deg.C for a 4 hour period for high and medium density
materials.
(v) Impact. The test must be performed in accordance with ASTM D
[[Page 716]]
4565-90a using an impact force of 4 newton-meters at a temperature of -
20 2 deg.C. A cracked or split jacket constitutes failure.
(6) Jacket thickness. The nominal outer jacket thickness must not be
less than 1.3 millimeters. The test method used must either be the End
Sample Method (paragraph (m)(6)(i) of this section) or the Continuous
Uniformity Thickness Gauge Method (paragraph (m)(6)(ii) of this
section).
(i) End sample method. The jacket must be capable of meeting the
following requirements:
Minimum Average Thickness: 90 percent (%) of nominal thickness
Minimum Spot Thickness: 70 % of nominal thickness
(ii) Continuous uniformity thickness gauge. (A) The jacket must be
capable of meeting the following requirements:
Minimum Average Thickness: 75 % of nominal thickness
Minimum Thickness: 70 % of nominal thickness
Maximum Eccentricity: 40 % of nominal thickness
[GRAPHIC] [TIFF OMITTED] TR05JY94.000
(B) The maximum and minimum thickness values shall be based on the
average of each axial section.
(7) For jackets having embedded strength members, the jacket
thickness must meet the requirements of paragraph (m)(6) of this section
except that the jacket thickness over the strength members must not be
less than 0.50 millimeters.
(8) The minimum jacket thickness at any point over the support
messenger for self-supporting aerial cable utilizing such an element
must be 1.1 millimeters.
(9) The web dimension for self-supporting aerial cable utilizing
such a feature must be as follows:
[GRAPHIC] [TIFF OMITTED] TR05JY94.001
(n) Sheath slitting cord (optional). (1) A sheath slitting cord is
optional.
(2) When a sheath slitting cord is used it must be nonhygroscopic
and nonwicking or be rendered such by the filling or flooding compound,
continuous throughout a length of cable and of sufficient strength to
open the sheath over at least a one meter length without breaking the
cord at a temperature of 235 deg.C.
(o) Identification marker and length marker. (1) Each length of
cable must be permanently labeled either Optical Cable, OC, Optical
Fiber Cable, or OF on the outer jacket and identified as to manufacturer
and year of manufacture.
(2) Each length of cable intended for direct burial installation
shall be marked with a telephone handset in compliance with Rule 350G of
the 1993 National Electrical Safety Code (NESC).
(3) Mark the number of fibers on the jacket.
(4) The markings must be printed on the jacket at regular intervals
of not more than 2 meters.
(5) An alternative method of marking may be used if acceptable to
RUS.
(6) The completed cable must have sequentially numbered length
markers in Meters or Feet at regular intervals of not more than 2 meters
along the outside of the jacket.
(7) Continuous sequential numbering must be employed in a single
length of cable.
(8) The numbers must be dimensioned and spaced to produce good
legibility and must be approximately 3 millimeters in height. An
occasional illegible marking is permissible if there is a legible
marking located not more than 2 meters from it.
(9) The method of marking must be by means of suitable surface
markings producing a clear distinguishable contrasting marking
acceptable to RUS.
[[Page 717]]
Where direct or transverse printing is employed, the characters should
be indented to produce greater durability of marking. Any other method
of length marking must be acceptable to RUS as producing a marker
suitable for the field. Size, shape and spacing of numbers, durability
and overall legibility of the marker will be considered in acceptance of
the method.
(10) Agreement between the actual length of the cable and the length
marking on the cable jacket must be within the limits of +1 percent, -0
percent.
(11) The color of the initial marking must be white or silver. If
the initial marking fails to meet the requirements of the preceding
paragraphs, it will be permissible to either remove the defective
marking and re-mark with the white or silver color or leave the
defective marking on the cable and re-mark with yellow. No further re-
marking is permitted. Any re-marking must be on a different portion of
the cable circumference than any existing marking when possible and have
a numbering sequence differing from any other existing marking by at
least 3,000.
(12) Any reel of cable that contains more than one set of sequential
markings must be labeled to indicate the color and sequence of marking
to be used. The labeling must be applied to the reel and also to the
cable.
(p) Optical performance. (1) The optical performance of the single
mode fibers must be in accordance with the requirements specified in
paragraphs (p)(1)(i) through (p)(1)(viii) of this section.
(i) The attenuation values of the single mode fibers within the
cable must not exceed 0.5 decibel per kilometer (dB/km) for dispersion-
unshifted single mode fiber at 1310 and 1550 nanometers and must not
exceed 0.5 dB/km for dispersion-shifted single mode fiber at 1550
nanometers. The test method used for measuring the attenuation must be
in accordance with either:
(A) EIA/TIA-455-78A; or
(B) EIA/TIA-455-61.
(ii) The attenuation values for wavelengths between 1285 and 1330
nanometers and between 1525 and 1575 nanometers for dispersion-unshifted
fibers must not exceed the attenuation at 1310 and 1550 nanometers by
more than 0.1 dB/km. The attenuation values for wavelengths between 1525
and 1575 nanometers for dispersion-shifted fibers must not exceed the
attenuation at 1550 nanometers by more than 0.1 dB/km. The test method
used for measuring the attenuation must be in accordance with any one of
the methods specified in paragraph (p)(1)(i) of this section.
(iii) Attenuation discontinuities in the fiber's length must not
exceed 0.1 decibel (dB) for dispersion-unshifted fiber at
131020 and 155020 nanometers and must not exceed
0.1 dB for dispersion-shifted fiber at 155020 nanometers
when measured in accordance with EIA/TIA-455-59.
(iv) Measurement of the attenuation must be conducted at the
wavelength specified for application and must be expressed in decibels
per kilometer.
(v) Because the accuracy of attenuation measurements for single mode
fibers becomes questionable when measured on short cable lengths,
attenuation measurements are to be made utilizing characterization cable
lengths. If the ship length of cable is less than one kilometer, the
attenuation values measured on longer lengths of cable (characterization
length of cable) before cutting to the ship lengths of cable may be
applied to the ship lengths.
(vi) For dispersion-unshifted fiber the zero dispersion wavelength
must be between 1300 and 1322 nanometers, and the value of the
dispersion slope at the zero-dispersion wavelength must not be greater
than 0.092 picosecond per nanometer squared times kilometer (ps/
(nm2/km) when measured in accordance with either:
(A) EIA/TIA-455-168A;
(B) EIA/TIA-455-169A; or
(C) EIA/TIA-455-175A.
(vii) For dispersion-shifted fiber, the dispersion over the
wavelength range between 1525 and 1575 nanometers must not exceed 3.5
picosecond per nanometer times kilometer (ps/(nm/km)) and must have a
maximum dispersion slope of 0.095 ps/(nm2/km) at the zero
dispersion wavelength when measured in accordance with any one
[[Page 718]]
of the test procedures specified in paragraph (p)(1)(vi) of this
section.
(viii) The cut off wavelength of the dispersion-unshifted and the
dispersion-shifted fibers in a cable must be less than 1260 nanometers
when measured in accordance with EIA/TIA-455-170.
(2) The optical performance of the multimode fibers must be in
accordance with the requirements specified in paragraphs (p)(2)(i)
through (p)(2)(vi) of this section.
(i) The attenuation values of the 50/125 and 62.5/125 micrometer
multimode fibers within the cable must not exceed 1.5 dB/km at 1300
nanometers when measured in accordance with either:
(A) EIA/TIA-455-46A;
(B) EIA/TIA-455-53A; or
(C) EIA/TIA-455-61.
(ii) Attenuation discontinuities in the fiber's length must not
exceed 0.2 dB for both multimode fiber types at 130020
nanometers when measured in accordance with EIA/TIA-455-59.
(iii) Measurement of the attenuation must be conducted at the
wavelength specified for application and must be expressed in decibels
per kilometer.
(iv) Because the accuracy of attenuation measurements for multimode
fibers becomes questionable when measured on short cable lengths,
attenuation measurements are to be made utilizing characterization cable
lengths. If the ship length of cable is less than one kilometer, the
attenuation values measured on longer lengths of cable (characterization
length of cable) before cutting to the ship lengths of cable may be
applied to the ship lengths.
(v) The bandwidth of the multimode fibers at the -3 dB optical power
of the optical fibers within the cable must be within the limits
prescribed in the purchase order.
(vi) The test methods used to measure bandwidth must be in
accordance with either EIA/TIA-455-30B or EIA/TIA-455-51A.
(3) Numerical aperture (NA) for each multimode optical fiber in the
cable must be 0.200.015 for the 50/125 micrometer design and
0.2750.015 for the 62.5/125 micrometer design when measured
in accordance with EIA/TIA-455-177A.
(q) Mechanical requirements--(1) Cable bend test. (i) All cables
manufactured in accordance with the requirements of this section must be
capable of meeting the following bend test without exhibiting an
increase in fiber attenuation greater than 0.10 dB for single mode
fibers and 0.40 dB for multimode fibers.
(ii) Measure the attenuation of dispersion-unshifted single mode
fibers at 131020 and 155020 nanometers,
dispersion-shifted single mode fibers at 155020 nanometers
and multimode fibers at 130020 nanometers.
(iii) After measuring the attenuation of the optical fibers, test
the cable sample in accordance with EIA/TIA-455-37A, Test Condition E,
Turns Test Level 3. The following detailed test conditions shall apply:
(A) Section 4.2--Mandrel diameter must be 20 times the cable
diameter.
(B) Section 4.5--Measure the attenuation increase of the wound
sample at the test temperature and specified wavelengths in accordance
with EIA-455-20.
(C) For armored cable, the armor overlap must be on the outside of
the bend.
(D) For self-supporting cable, the jacketed support messenger and
connection web must be removed prior to testing.
(iv) The cable may be allowed to warm to room temperature before
visual inspection. The bent area of the cable must show neither visible
evidence of fracture of the jacket nor delamination of the bond at the
overlap and to the outer jacket in nonflooded cable. After removal of
the jacket, there must be no visible evidence of fracture of the armor,
when present, and of the components in the core.
(2) Cable impact test. (i) All cables manufactured in accordance
with the requirements of this section must be capable of meeting the
following impact test without exhibiting an increase in fiber
attenuation greater than 0.10 dB for single mode fibers and 0.40 dB for
multimode fibers, and without cracking or splitting of the cable jacket.
(ii) Measure the attenuation of the optical fibers in accordance
with paragraph (q)(1)(ii) of this section.
[[Page 719]]
(iii) After measuring the attenuation of the optical fibers, test
the cable in accordance with EIA/TIA-455-25A.
(3) Cable compression test. (i) All cables manufactured in
accordance with the requirements of this section must be capable of
meeting the following compressive strength test without exhibiting an
increase in fiber attenuation greater than 0.10 dB for single mode
fibers and 0.4 dB for multimode and without cracking or splitting of the
cable jacket when subjected to a minimum compressive load of 440 newtons
per centimeter for armored cable and 220 newtons per centimeter for
nonarmored cable.
(ii) Measure the attenuation of the optical fibers in accordance
with paragraph (q)(1)(ii) of this section.
(iii) After measuring the attenuation of the optical fibers, test
the cable in accordance with EIA-455-41 using a rate of 3 millimeters to
20 millimeters per minute and maintaining the load for 10 minutes.
(4) Cable twist test. (i) All cables manufactured in accordance with
the requirements of this section must be capable of meeting the
following twist test without exhibiting an increase in fiber attenuation
greater than 0.10 dB for single mode fibers and 0.40 dB for multimode
fibers, and without cracking or splitting of the cable jacket.
(ii) Measure the attenuation of the optical fibers in accordance
with paragraph (q)(1)(ii) of this section.
(iii) After measuring the attenuation of the optical fibers, test
the cable in accordance with EIA/TIA-455-85A, using a maximum cable
twisting length of 4 meters.
(5) Cable flex test. (i) All cables manufactured in accordance with
the requirements of this section must be capable of meeting the
following flex test without exhibiting an increase in fiber attenuation
greater than 0.10 dB for single mode fibers and 0.40 dB for multimode
fibers.
(ii) Measure the attenuation of the optical fibers in accordance
with paragraph (q)(1)(ii) of this section.
(iii) After measuring the attenuation of the optical fibers, test
the cable in accordance with EIA/TIA-455-104A, Test Conditions I and II,
flexed for 25 cycles using a sheave diameter not less than 20 times the
cable diameter (Test condition letter B).
(iv) After completion of the test, the bent area of the cable must
show neither visible evidence of fracture of the jacket nor delamination
of the bond at the overlap and to the outer jacket in nonflooded cable.
After removal of the jacket, there must be no visible evidence of
fracture of the armor, when present, and of the components in the core.
(6) Water penetration test. (i) A one meter length of completed
fiber optic cable must be preconditioned for 24 hours at 235
deg.C and then tested in accordance with EIA/TIA-455-82B using a one
meter water head over the sample or placed under the equivalent
continuous pressure for one hour.
(ii) After the one hour period, there must be no water leakage
through the sheath interfaces, under the core wrap, between the cable
core interstices or through the fiber buffers.
(iii) If water leakage is detected in the first sample, one
additional 3 meter sample from EACH END of the same reel must be tested
in accordance with paragraph (q)(6)(i) of this section. If either sample
exhibits water leakage, the entire reel of cable is to be rejected. If
the samples exhibit no leakage, the entire reel of cable is considered
acceptable.
(7) Compound flow test. (i) Three 300 millimeter long test samples
must be preconditioned for 24 hours at 235 deg.C and then
tested in accordance with EIA/TIA-455-81A using a test temperature of 80
1 deg.C.
(ii) The amount of filling or flooding compounds that flowed or
dripped from any of the suspended cable specimens must be less than or
equal to 0.5 grams of material. The measurement of an amount greater
than 0.5 grams for any of the suspended cable specimens constitutes
failure.
(r) Preconnectorized cable (optional). (1) At the option of the
manufacturer and upon request by the purchaser, the cable may be factory
terminated with connectors acceptable to RUS.
(2) All connectors must be accepted by RUS prior to their use.
(s) Acceptance testing and extent of testing. (1) The tests
described in appendix A of this section are intended for
[[Page 720]]
acceptance of cable designs and major modifications of accepted designs.
What constitutes a major modification is at the discretion of RUS. These
tests are intended to show the inherent capability of the manufacturer
to produce cable products that have satisfactory performance
characteristics, long life and long-term optical stability but are not
intended as field tests.
(2) For initial acceptance, the manufacturer must submit:
(i) An original signature certification that the product fully
complies with each section of the specification;
(ii) Qualification Test Data, per appendix A of this section;
(iii) A set of instructions for handling the cable;
(iv) OSHA Material Safety Data Sheets for all components;
(v) Agree to periodic plant inspections;
(vi) A certification that the product does or does not comply with
the domestic origin manufacturing provisions, of the ``Buy American''
requirements of the Rural Electrification Act of 1938 (52 Stat. 818);
(vii) Written user testimonials concerning field performance of the
product; and
(viii) Other nonproprietary data deemed necessary by the Chief,
Outside Plant Branch (Telephone).
(3) For requalification acceptance, the manufacturer must submit an
original signature certification that the product fully complies with
each section of the specification, excluding the Qualification Section,
and a certification that the product does or does not comply with the
domestic origin manufacturing provisions of the ``Buy American''
requirements of the Rural Electrification Act of 1938 (52 Stat. 818),
for acceptance by September 30 every three years. The required data and
certification must have been gathered within 90 days of the submission.
(4) Initial and requalification acceptance requests should be
addressed to: Chairman, Technical Standards Committee ``A'' (Telephone),
Telecommunications Standards Division, Rural Utilities Service,
Washington, DC 20250-1500.
(5) Tests on 100 percent of completed cable. (i) The armor for each
length of cable must be tested for continuity using the procedures of
ASTM D 4566-90.
(ii) Attenuation for each optical fiber in the cable must be
measured.
(iii) Optical discontinuities must be isolated and their location
and amplitude recorded.
(6) Capability tests. Tests on a quality assurance basis must be
made as frequently as is required for each manufacturer to determine and
maintain compliance with:
(i) Numerical aperture and bandwidth of multimode fibers;
(ii) Cut off wavelength of single mode fibers;
(iii) Dispersion of single mode fibers;
(iv) Shrinkback and cold testing of loose tube and tight tube
buffers;
(v) Adhesion properties of the protective fiber coating;
(vi) Dielectric strength between the armor and the metallic central
member;
(vii) Performance requirements for the inner and outer jacketing
materials;
(viii) Performance requirements for the filling and flooding
compounds;
(ix) Bonding properties of the coated armoring material;
(x) Sequential marking and lettering;
(xi) Cable bend and cable impact tests;
(xii) Water penetration and compound flow tests;
(xiii) Cable twist, cable flex, and cable compression tests; and
(xiv) Performance requirements of support messenger.
(t) Records of optical and physical tests. (1) Each manufacturer
must maintain suitable summary records for a period of at least 3 years
of all optical and physical tests required on completed cable by this
section as set forth in paragraphs (s)(5) and (s)(6) of this section.
The test data for a particular reel must be in a form that it may be
readily available to RUS upon request. The optical data must be
furnished to the purchaser on a suitable and easily readable form.
(2) Measurements and computed values must be rounded off to the
number
[[Page 721]]
of places or figures specified for the requirement according to ASTM E
29-90.
(u) Manufacturing irregularities. (1) Repairs to the armor, when
present, are not permitted in cable supplied to end users under this
section.
(2) Minor defects in the inner and outer jacket (defects having a
dimension of 3 millimeter or less in any direction) may be repaired by
means of heat fusing in accordance with good commercial practices
utilizing sheath grade compounds.
(3) Buffer tube repair is permitted only in conjunction with fiber
splicing.
(v) Packaging and preparation for shipment. (1) The cable must be
shipped on reels. The diameter of the drum must be large enough to
prevent damage to the cable from reeling and unreeling. The reels must
be substantial and so constructed as to prevent damage during shipment
and handling.
(2) A circumferential thermal wrap or other means of protection
complying with the requirements of appendix B of this section must be
secured between the outer edges of the reel flange to protect the cable
against damage during storage and shipment.
(3) Cable manufactured to the requirements of this section must be
sealed at the ends to prevent entrance of moisture. The method of
sealing must be accepted by RUS prior to its use.
(4) The end-of-pull (outer end) of the cable must be securely
fastened to prevent the cable from coming loose during transit. The
start-of-pull (inner end) of the cable must project through a slot in
the flange of the reel, around an inner riser, or into a recess on the
reel flange near the drum and fastened in such a way to prevent the
cable from becoming loose during installation.
(5) Spikes, staples or other fastening devices must be used in a
manner which will not result in penetration of the cable.
(6) The arbor hole must admit a spindle 63.5 millimeters in diameter
without binding. Steel arbor hole liners may be used but must be
accepted by RUS prior to their use.
(7) Each reel must be plainly marked to indicate the direction in
which it should be rolled to prevent loosening of the cable on the reel.
(8) Each reel must be stenciled or lettered with the name of the
manufacturer.
(9) The following information must be either stenciled on the reel
or on a tag firmly attached to the reel:
Optical Cable
Number of Fibers
Armored or Nonarmored
Year of Manufacture
Name of Cable Manufacturer
Length of Cable
Reel Number
RUS 7 CFR 1755.900
Example:
Optical Cable
4 fiber
Armored
1988
XYZ Company
1050 meters
Reel Number 3
RUS 7 CFR 1755.900
(10) When preconnectorized cable is shipped, the splicing modules
must be protected to prevent damage during shipment and handling. The
protection method must be accepted by RUS prior to its use.
(The information collection and recordkeeping requirements of this
section have been approved by the Office of Management and Budget (OMB)
under control number 0572-0059)
Appendix A to Sec. 1755.900--Qualification Tests Methods
(I) The test procedures described in this appendix are for
qualification of initial cable designs and major modifications of
accepted designs. Included in (V) of this appendix are suggested formats
that may be used in submitting test results to RUS.
(II) Sample selection and preparation. (1) All testing must be
performed on lengths removed sequentially from any of the same cables
listed below. The cables must not have been exposed to temperatures in
excess of 38 deg.C since their initial cool downs after sheathing. The
lengths specified are minimum lengths and if desirable from a laboratory
testing standpoint longer lengths may be used:
(a) 12 single mode fiber jacketed cable consisting of 6 single mode
dispersion-unshifted fibers and 6 single mode dispersion-shifted fibers.
(b) 12 multimode fiber jacketed cable consisting of 6 50/125
micrometer multimode fibers and 6 62.5/125 micrometer multimode fibers.
(c) 24 fiber jacketed combination cable consisting of 6 single mode
dispersion-unshifted
[[Page 722]]
fibers; 6 single mode dispersion-shifted fibers; 6 50/125 micrometer
multimode fibers; and 6 62.5/125 micrometer multimode fibers.
(2) Length A shall be a minimum of 500 meters long. Coil the sample
with a diameter of 50 to 75 times its sheath diameter. Three lengths are
required if only requesting acceptance for either single mode fiber
cable (a), multimode fiber cable (b), or using the combination fiber
cable (c). Six lengths, 3 lengths of single mode fiber cable (a), and 3
lengths of multimode fiber cable (b), are required if requesting
acceptance for both single mode and multimode fiber cables.
(3) Length B shall be one meter long. Four lengths of either single
mode fiber cable (a), multimode fiber cable (b) or the combination fiber
cable (c) are required.
(4) Length C shall be 600 millimeters long. Four lengths of either
single mode fiber cable (a), multimode fiber cable (b) or the
combination fiber cable (c) are required.
(5) Data reference temperature. Unless otherwise specified, all
measurement shall be made at 235 deg.C.
(III) Environmental tests--(1) Heat aging test. (a) Test samples.
Place one or two samples of length A and one sample each of lengths B
and C in an oven or environmental chamber. The ends of sample A must
exit from the chamber or oven for optical tests. Securely seal the oven
exit holes.
(b) Sequence of tests. The samples are to be subjected to the
following tests after conditioning:
(i) Water Penetration Test outlined in paragraph (III ) (2) of this
appendix; and
(ii) Jacket Slip Strength Test outlined in paragraph (III) (3) of
this appendix. (For Flooded Designs Only)
(c) Initial measurements. (i) For sample(s) A measure the
attenuation for the single mode dispersion-unshifted fibers at 1310 and
1550 nanometers, for single mode dispersion-shifted fibers at 1550
nanometers and/or for multimode fibers at 1300 nanometers at a
temperature of 235 deg.C. Also measure the bandwidth of the
multimode fibers. Calculate the attenuation data on a per kilometer
basis. Calculate the bandwidth data on a megahertz-kilometer (MHz-km)
basis.
(ii) Record on suggested formats in (V) of this appendix or on other
easily readable formats.
(d) Heat conditioning. (i) Immediately after completing the initial
measurements, condition the sample(s) for 14 days at a temperature of
652 deg.C.
(ii) At the end of this period note any exudation of cable filler.
Measure the parameters given in paragraph (III)(1)(c) of this appendix.
Record on suggested formats in (V) of this appendix or on other easily
readable formats.
(e) Overall optical deviation. (i) Calculate the change in all
parameters between the final parameters after conditioning with initial
parameters in paragraph (III)(1)(c) of this appendix.
(ii) The stability of the optical parameters after completion of
this test must be within the following prescribed limits:
(A) Attenuation. The attenuation of each multimode fiber must not
change by more than 0.3 db/km and the attenuation of each single mode
fiber must not change by more than 0.1 dB/km.
(B) Bandwidth. The bandwidth of each multimode fiber must not change
by more than 15 percent from their original values.
(2) Water penetration testing. (a) A watertight closure must be
placed over the jacket of length B from paragraph (III)(1)(a) of this
appendix. The closure must not be placed over the jacket so tightly that
the flow of water through pre-existing voids or air spaces is
restricted. The other end of the sample must remain open.
(b) Test per Option A or Option B. (i) Option A. Weigh the sample
and closure prior to testing. Fill the closure with water and place
under a continuous pressure of 10 0.7 kilopascals for one
hour. Collect the water leakage from the end of the test sample during
the test and weigh to the nearest 0.1 gram. Immediately after the one
hour test, seal the ends of the cable with a thin layer of grease and
remove all visible water from the closure, being careful not to remove
water that penetrated into the core during the test. Reweigh the sample
and determine the weight of water that penetrated into the core.
(ii) Option B. Fill the closure with a 0.2 gram sodium fluorscein
per liter water solution and apply a continuous pressure of 10
0.7 kilopascals for one hour. Catch and weigh any water that
leaks from the end of the cable during the one hour period. If no water
leaks from the sample, carefully remove the water from the closure. Then
carefully remove the outer jacket, armor, if present, inner jacket, if
present, and core wrap one at a time, examining with an ultraviolet
light source for water penetration. After removal of the core wrap,
carefully dissect the core and examine for water penetration within the
core. Where water penetration is observed, measure the penetration
distance.
(3) Jacket slip strength test. (For Flooded Design Only) (a) Sample
selection. Test sample C from paragraph (III)(1)(a) of this appendix.
(b) Sample preparation. Prepare test sample in accordance with the
procedures specified in ASTM D 4565-90a.
(c) Sample conditioning and testing. Remove the sample from the
tensile tester prior to testing and condition for one hour at 50
2 deg.C. Test immediately in accordance with the procedures
specified in ASTM D 4565-90a. A minimum jacket slip strength of 67
newtons is required. Record the load attained on the
[[Page 723]]
suggested formats in (V) of this appendix or on other easily readable
formats.
(4) Temperature and humidity exposure. (a) Repeat paragraphs
(III)(1)(a) through (III)(1)(c)(ii) of this appendix for separate set of
samples A, B and C which have not been subjected to prior environmental
conditioning.
(b) Immediately after completing the measurements, expose the test
sample to 100 temperature cyclings. Relative humidity within the chamber
shall be maintained at 90 2 percent. One cycle consists of
beginning at a stabilized chamber and test sample temperature of 52
2 deg.C, increasing the temperature to 57 2
deg.C, allowing the chamber and test samples to stabilize at this level,
then dropping the temperature back to 52 2 deg.C.
(c) Repeat paragraphs (III)(1)(d)(ii) through (III)(3)(c) of this
appendix.
(5) Temperature cycling. (a) Repeat paragraphs (III)(1)(a) through
(III)(1)(c)(ii) of this appendix for separate set of samples A, B, and C
which have not been subjected to prior environmental conditioning.
(b) Immediately after completing the measurements, subject the test
sample to 10 cycles of temperature between -40 deg.C and +60 deg.C.
The test sample must be held at each temperature extreme for a minimum
of 1\1/2\ hours during each cycle of temperature. The air within the
temperature cycling chamber must be circulated throughout the duration
of the cycling.
(c) Repeat paragraphs (III)(1)(d)(ii) through (III)(3)(c) of this
appendix.
(IV) Control sample--(a) Test samples. A separate set of lengths B
and C must have been maintained at 23 5 deg.C for at least
48 hours before the testing.
(b) Repeat paragraphs (III)(2) through (III)(3)(c) of this appendix
for these samples.
(V) The following suggested formats may be used in submitting the
test results to RUS:
Heat Aging Test--Single Mode Cable
------------------------------------------------------------------------
Attenuation--1310 nm dB/km Attenuation--1550 nm dB/km
Fiber No. -----------------------------------------------------------
Initial Final Change Initial Final Change
------------------------------------------------------------------------
1
------------------------------------------------------------------------
2
------------------------------------------------------------------------
3
------------------------------------------------------------------------
4
------------------------------------------------------------------------
5
------------------------------------------------------------------------
6
------------------------------------------------------------------------
7
------------------------------------------------------------------------
8
------------------------------------------------------------------------
9
------------------------------------------------------------------------
10
------------------------------------------------------------------------
11
------------------------------------------------------------------------
12
------------------------------------------------------------------------
[[Page 724]]
Heat Aging Test--Multimode Cable
------------------------------------------------------------------------
Attenuation--1300 nm dB/km Bandwidth dB/km
-----------------------------------------------------------
Fiber No. Change
Initial Final Change Initial Final (%)
------------------------------------------------------------------------
1
------------------------------------------------------------------------
2
------------------------------------------------------------------------
3
------------------------------------------------------------------------
4
------------------------------------------------------------------------
5
------------------------------------------------------------------------
6
------------------------------------------------------------------------
7
------------------------------------------------------------------------
8
------------------------------------------------------------------------
9
------------------------------------------------------------------------
10
------------------------------------------------------------------------
11
------------------------------------------------------------------------
12
------------------------------------------------------------------------
Heat Aging Test--Combination Cable
----------------------------------------------------------------------------------------------------------------
Attenuation--1310 nm dB/km Attenuation--1550 nm dB/km Bandwidth MHz-km
------------------------------------------------------------------------------------------------
Fiber No. Change
Initial Final Change Initial Final Change Initial Final (%)
----------------------------------------------------------------------------------------------------------------
1
----------------------------------------------------------------------------------------------------------------
2
----------------------------------------------------------------------------------------------------------------
3
----------------------------------------------------------------------------------------------------------------
4
----------------------------------------------------------------------------------------------------------------
5
----------------------------------------------------------------------------------------------------------------
6
----------------------------------------------------------------------------------------------------------------
7
----------------------------------------------------------------------------------------------------------------
8
----------------------------------------------------------------------------------------------------------------
9
----------------------------------------------------------------------------------------------------------------
10
----------------------------------------------------------------------------------------------------------------
11
----------------------------------------------------------------------------------------------------------------
12
----------------------------------------------------------------------------------------------------------------
13
----------------------------------------------------------------------------------------------------------------
14
----------------------------------------------------------------------------------------------------------------
15
----------------------------------------------------------------------------------------------------------------
16
----------------------------------------------------------------------------------------------------------------
17
----------------------------------------------------------------------------------------------------------------
18
----------------------------------------------------------------------------------------------------------------
19
----------------------------------------------------------------------------------------------------------------
[[Page 725]]
20
----------------------------------------------------------------------------------------------------------------
21
----------------------------------------------------------------------------------------------------------------
22
----------------------------------------------------------------------------------------------------------------
23
----------------------------------------------------------------------------------------------------------------
24
----------------------------------------------------------------------------------------------------------------
Temperature/Humidity Test--Single Mode Cable
------------------------------------------------------------------------
Attenuation--1310 nm dB/km Attenuation--1550 nm dB/km
Fiber No. -----------------------------------------------------------
Initial Final Change Initial Final Change
------------------------------------------------------------------------
1
------------------------------------------------------------------------
2
------------------------------------------------------------------------
3
------------------------------------------------------------------------
4
------------------------------------------------------------------------
5
------------------------------------------------------------------------
6
------------------------------------------------------------------------
7
------------------------------------------------------------------------
8
------------------------------------------------------------------------
9
------------------------------------------------------------------------
10
------------------------------------------------------------------------
11
------------------------------------------------------------------------
12
------------------------------------------------------------------------
[[Page 726]]
Temperature/Humidity Test--Multimode Cable
------------------------------------------------------------------------
Attenuation--1300 nm dB/km Bandwidth MHz-km
Fiber No. -----------------------------------------------------------
Initial Final Change Initial Final Change
------------------------------------------------------------------------
1
------------------------------------------------------------------------
2
------------------------------------------------------------------------
3
------------------------------------------------------------------------
4
------------------------------------------------------------------------
5
------------------------------------------------------------------------
6
------------------------------------------------------------------------
7
------------------------------------------------------------------------
8
------------------------------------------------------------------------
9
------------------------------------------------------------------------
10
------------------------------------------------------------------------
11
------------------------------------------------------------------------
12
------------------------------------------------------------------------
Temperature/Humidity Test--Combination Cable
----------------------------------------------------------------------------------------------------------------
Attenuation--1310 nm dB/km Attenuation--1550 nm dB/km Bandwidth MHz-km
------------------------------------------------------------------------------------------------
Fiber No. Change
Initial Final Change Initial Final Change Initial Final (%)
----------------------------------------------------------------------------------------------------------------
1
----------------------------------------------------------------------------------------------------------------
2
----------------------------------------------------------------------------------------------------------------
3
----------------------------------------------------------------------------------------------------------------
4
----------------------------------------------------------------------------------------------------------------
5
----------------------------------------------------------------------------------------------------------------
6
----------------------------------------------------------------------------------------------------------------
7
----------------------------------------------------------------------------------------------------------------
8
----------------------------------------------------------------------------------------------------------------
9
----------------------------------------------------------------------------------------------------------------
10
----------------------------------------------------------------------------------------------------------------
11
----------------------------------------------------------------------------------------------------------------
12
----------------------------------------------------------------------------------------------------------------
13
----------------------------------------------------------------------------------------------------------------
14
----------------------------------------------------------------------------------------------------------------
15
----------------------------------------------------------------------------------------------------------------
16
----------------------------------------------------------------------------------------------------------------
17
----------------------------------------------------------------------------------------------------------------
18
----------------------------------------------------------------------------------------------------------------
19
----------------------------------------------------------------------------------------------------------------
[[Page 727]]
20
----------------------------------------------------------------------------------------------------------------
21
----------------------------------------------------------------------------------------------------------------
22
----------------------------------------------------------------------------------------------------------------
23
----------------------------------------------------------------------------------------------------------------
24
----------------------------------------------------------------------------------------------------------------
Temperature Cycling Test--Single Mode Cable
------------------------------------------------------------------------
Attenuation--1310 nm dB/km Attenuation--1550 nm dB/km
Fiber No. -----------------------------------------------------------
Initial Final Change Initial Final Change
------------------------------------------------------------------------
1
------------------------------------------------------------------------
2
------------------------------------------------------------------------
3
------------------------------------------------------------------------
4
------------------------------------------------------------------------
5
------------------------------------------------------------------------
6
------------------------------------------------------------------------
7
------------------------------------------------------------------------
8
------------------------------------------------------------------------
9
------------------------------------------------------------------------
10
------------------------------------------------------------------------
11
------------------------------------------------------------------------
12
------------------------------------------------------------------------
[[Page 728]]
Temperature Cycling--Multimode Cable
------------------------------------------------------------------------
Attenuation--1300 nm dB/km Bandwidth MHz-km
-----------------------------------------------------------
Fiber No. Change
Initial Final Change Initial Final (%)
------------------------------------------------------------------------
1
------------------------------------------------------------------------
2
------------------------------------------------------------------------
3
------------------------------------------------------------------------
4
------------------------------------------------------------------------
5
------------------------------------------------------------------------
6
------------------------------------------------------------------------
7
------------------------------------------------------------------------
8
------------------------------------------------------------------------
9
------------------------------------------------------------------------
10
------------------------------------------------------------------------
11
------------------------------------------------------------------------
12
------------------------------------------------------------------------
Temperature Cycling Test Combination Cable
----------------------------------------------------------------------------------------------------------------
Attenuation--1310 nm dB/km Attenuation--1550 nm dB/km Bandwidth MHz-km
------------------------------------------------------------------------------------------------
Fiber No. Change
Initial Final Change Initial Final Change Initial Final (%)
----------------------------------------------------------------------------------------------------------------
1
----------------------------------------------------------------------------------------------------------------
2
----------------------------------------------------------------------------------------------------------------
3
----------------------------------------------------------------------------------------------------------------
4
----------------------------------------------------------------------------------------------------------------
5
----------------------------------------------------------------------------------------------------------------
6
----------------------------------------------------------------------------------------------------------------
7
----------------------------------------------------------------------------------------------------------------
8
----------------------------------------------------------------------------------------------------------------
9
----------------------------------------------------------------------------------------------------------------
10
----------------------------------------------------------------------------------------------------------------
11
----------------------------------------------------------------------------------------------------------------
12
----------------------------------------------------------------------------------------------------------------
13
----------------------------------------------------------------------------------------------------------------
14
----------------------------------------------------------------------------------------------------------------
15
----------------------------------------------------------------------------------------------------------------
16
----------------------------------------------------------------------------------------------------------------
17
----------------------------------------------------------------------------------------------------------------
18
----------------------------------------------------------------------------------------------------------------
19
----------------------------------------------------------------------------------------------------------------
[[Page 729]]
20
----------------------------------------------------------------------------------------------------------------
21
----------------------------------------------------------------------------------------------------------------
22
----------------------------------------------------------------------------------------------------------------
23
----------------------------------------------------------------------------------------------------------------
24
----------------------------------------------------------------------------------------------------------------
Water Penetration Test
------------------------------------------------------------------------
Option A Option B
---------------------------------------
End Weight End
leakage gain leakage Penetration
grams grams grams millimeters
------------------------------------------------------------------------
Control.........................
Heat Age........................
Humidity Exposure...............
Temperature Cycling.............
------------------------------------------------------------------------
Jacket Slip Strength @ 50 deg.C
------------------------------------------------------------------------
Load in
Newtons
Control....................................................
Heat Age...................................................
Humidity Exposure..........................................
Temperature Cycling........................................
Filler
Exudation
(grams)
Heat Age...................................................
Humidity Exposure..........................................
Temperature Cycle..........................................
------------------------------------------------------------------------
Appendix B to 7 CFR 1755.900--Thermal Reel Wrap Qualification
(I) The test procedures described in this appendix are only for
qualification of initial and subsequent changes in thermal reel wraps.
(II) Sample selection. All testing must be performed on two 450
millimeter lengths of cable removed sequentially from the same fiber
jacketed cable. This cable must not have been exposed to temperatures in
excess of 38 deg.C since its initial cool down after sheathing.
(III) Test procedure. (1) Place the two samples on an insulating
material such as wood.
(2) Tape thermocouples to the jackets of each sample to measure the
jacket temperature.
(3) Cover one sample with the thermal reel wrap.
(4) Expose the samples to a radiant heat source capable of heating
the uncovered jacket sample to a minimum of 71 deg.C. A GE 600 watt
photoflood lamp or an equivalent lamp having the light spectrum
approximately that of the sun shall be used.
(5) The height of the lamp above the jacket shall be 380 millimeters
or an equivalent height that produces the 71 deg.C jacket temperature
on the unwrapped sample shall be used.
(6) After the samples have stabilized at the temperature, the jacket
temperatures of the samples shall be recorded after one hour of exposure
to the heat source.
(7) Compute the temperature difference between jackets.
(8) For the thermal reel wrap to be acceptable to RUS, the
temperature difference between the jacket with the thermal reel wrap and
the jacket without the reel wrap shall be greater than or equal to 17
deg.C.
[59 FR 34360, July 5, 1994; 59 FR 44795, Aug. 30, 1994, as amended at 60
FR 1711, Jan. 5, 1995]