Tyco Electronics Corporation
300 Constitutional Drive
Menlo Park, CA 94025 USA
Specification
This Issue:
Date:
Replaces:
RT-1171
Issue 7
December 5, 2001
Issue 6
Thermofit® MIL-LT Tubing
Low Shrink-Temperature
Polyolefin, Flexible, Heat-Shrinkable
1.
SCOPE
This specification covers requirements for flexible electrical insulating, extruded tubing whose diameter will
reduce to a predetermined size upon the application of heat in excess of 90°C (194°F).
2.
APPLICABLE DOCUMENTS
This specification takes precedence over documents referenced herein. Unless otherwise specified, the latest
issue of referenced documents applies. The following documents form a part of this specifications to the
extent specified herein.
2.1
GOVERNMENT-FURNISHED DOCUMENTS
Military
MIL-H-5606
Hydraulic Fluid, Petroleum Base, Aircraft, Missile and Ordnance
Mil-DTL-83133 Turbine Fuels, Aviation, Kerosene Types, NATO F-34 (JP-8), NATO F-35 and JP-8+100
MIL-L-7808
Lubricating Oil, Aircraft Turbine Engine, Synthetic Base
MIL-STD-104 Limits for Electrical Insulation Color
MIL-A-8243
Anti-icing and deicing-Defrosting Fluids
MIL-L-23699
Lubricating Oil, Aircraft Turbine Engines, Synthetic Base
2.2
OTHER PUBLICATIONS
ISO 846
Plastics-Evaluation of the action of microorganisms
American Society for Testing and Materials (ASTM)
D 2240
Standard Test Method for Rubber Property - Durometer Hardness
D 2671
Standard Methods of Testing Heat-Shrinkable Tubing for Electrical Use
(Copies of ASTM publications may be obtained from the American Society for Testing and Materials, 1916
Race Street, Philadelphia, Pennsylvania 19103.)
3.
3.1
REQUIREMENTS
MATERIALS
The tubing shall be fabricated form thermally stabilized, modified polyolefin and shall be crosslinked by
irradiation. It shall be homogeneous and essentially free from flaws, defects, pinholes, bubbles, seams,
cracks, and inclusions.
3.2
PROPERTIES
The tubing shall meet the requirements of Table 3.
3.3
COLOR
The tubing shall be available in black, white, red, yellow or blue, unless otherwise specified.
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Page 2
SPECIFICATION RT-1171 ISSUE 7
4.
4.1
4.1.1
QUALITY ASSURANCE PROVISIONS
CLASSIFICATION OF TESTS
Qualification Tests
Qualification tests are those performed on tubing submitted for qualification as a satisfactory product and
shall consist of all tests listed in this specification.
4.1.2
Acceptance Tests
Acceptance tests are those performed on tubing submitted for acceptance under contract. Acceptance tests
shall consist of the following:
Dimensions
Longitudinal Change
Tensile Strength
Ultimate Elongation
Flammability
Heat Shock
Low Temperature Flexibility
4.2
4.2.1
SAMPLING INSTRUCTIONS
Qualification Test Samples
Qualification test samples shall consist of 50 feet (125 m) of black and white tubing. Qualification of black
and white shall qualify all colors. Qualification of any size within each size range specified below shall
qualify all sizes within that size range.
Size Range
3/64 through 1/8
3/16 through 3/4
1 through 4
4.2.2
Acceptance Test Samples
Acceptance test samples shall consist of not less than 16 feet (5 m) of tubing selected at random from each
lot. A lot shall consist of all tubing of the same size, from the same production run, and offered for
inspection at the same time.
4.3
TEST PROCEDURES
Unless otherwise specified, perform tests on specimens which have been fully recovered by conditioning for
3 minutes in a 200 ± 5°C (392 ± 9°F) oven. Condition the test specimens (and measurement gauges, when
applicable) for 3 hours at 23 ± 3°C (73 ± 5°F) and 50 ± 5 percent relative humidity for 3 hours prior to all
testing. Use mechanical convection type ovens in which air passes the specimens at a velocity of 100 to 200
feet (30 to 60 m) per minute.
4.3.1
Dimensions and Longitudinal Change
Measure three 6-inch (150 mm) specimens of tubing as supplied, for length ± 1/32 inch
(± 1 mm), and inside diameter in accordance with ASTM D 2671. Condition the specimens for
3 minutes in a 200 ± 5°C (392 ± 9°F) oven, cool to 23 ± 3°C (73 + 5°F), and then remeasure. Prior to and
after conditioning, the dimensions of the tubing shall be in accordance with Table 1 and the longitudinal
change shall be in accordance with Table 3. Calculate the longitudinal change as follows:
C =
Where:
L1 - L0
x 100
L0
C = Longitudinal Change [percent]
L0 = Length Before Conditioning [inches (mm)]
L1 = Length After Conditioning [inches (mm)]
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SPECIFICATION RT-1171 ISSUE 7
Page 3
4.3.2
Tensile Strength and Ultimate Elongation
Determine the tensile strength and ultimate elongation of the tubing in accordance with
ASTM D 2671 using 1-inch (25-mm) bench marks, a 1-inch (25-mm) initial jaw separation, and jaw
separation speed of 20 ± 2 inches (500 ± 50 mm) per minute.
4.3.3
Low Temperature Flexibility
Test three specimens of tubing for low temperature flexibility as follows: for tubing sizes
3/4-inch expanded and smaller, shrink and condition the tubing as specified in 4.3 onto a stranded AWG wire
(nearest AWG which is larger than the tubing maximum I.D. nominal after unrestricted shrinkage). For
tubing sizes larger than 3/4-inch, cut a 6 x 1/4-inch (150 x 6-mm) longitudinal strip from tubing that has been
recovered. Condition the specimens and a mandrel, selected from Table 2, in a cold chamber for 4 hours at 55 ± 3°C (-67 ± 5°F). After completion of the conditioning period and while still in the cold chamber at the
specified temperature, bend the specimen around the mandrel through not less than 360 degrees in 10 ± 2
seconds. Visually examine the tubing for cracks.
4.4
REJECTION AND RETEST
Failure of any sample of tubing to conform to any one of the requirements of this specification shall be cause
for rejection of the lot represented. Tubing which has been rejected may be replaced or reworked to correct
the defect and then resubmitted for acceptance. Before resubmitting, full particulars concerning previous
rejection and action taken to correct the defects shall be furnished to the inspector.
5.
5.1
PREPARATION FOR DELIVERY
FORM
The tubing shall be supplied on spools, unless otherwise specified.
5.2
PACKAGING
Packaging shall be in accordance with good commercial practice.
5.3
MARKING
Each container of tubing shall be permanently and legibly marked with the size, quantity, manufacturer's
identification, specification number, and lot number.
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Page 4
SPECIFICATION RT-1171 ISSUE 7
TABLE 1
Tubing Dimensions
Size
3/64
1/16
3/32
1/8
3/16
1/4
3/8
1/2
3/4
1
1-1/2
2
3
4
As Supplied
Inside Diameter
Minimum
mm.
in.
.046
1.17
.063
1.60
.093
2.36
.125
3.18
.187
4.75
.250
6.35
.375
9.53
.500
12.70
.750
19.05
1.000
25.40
1.500
38.10
2.000
50.80
3.000
76.20
4.000
101.60
As Recovered
Inside Diameter
Maximum
mm.
in.
.023
0.58
.031
0.79
.046
1.17
.062
1.58
.093
2.36
.125
3.18
.187
4.75
.250
6.35
.375
9.53
.500
12.70
.750
19.05
1.000
25.40
1.500
38.10
2.000
50.80
Minimum
mm.
in.
.013
0.33
.014
0.35
.017
0.43
.017
0.43
.017
0.43
.022
0.56
.022
0.56
.022
0.56
.027
0.68
.030
0.76
.034
0.86
.038
0.96
.042
1.06
.046
1.16
Wall Thickness
Maximum
mm.
in.
.019
0.48
.020
0.50
.023
0.58
.023
0.58
.023
0.58
.028
0.71
.028
0.71
.028
0.71
.033
0.84
.040
1.01
.046
1.17
.052
1.32
.058
1.47
.064
1.63
TABLE 2
Mandrel Dimensions for Bend Testing
Tubing Size
3/64 to 1/4 inclusive
3/8 to 1/2 inclusive
3/4 to 2 inclusive
3 to 4
Mandrel Diameter
mm.
in.
5/16 ± 0.002
7.9 ± 0.05
3/8 ± 0.003
9.5 ± 0.08
7/16 ± 0.004
11.1 ± 0.10
7/8 ± 0.005
22.2 ± 0.13
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in.
.016
.017
.020
.020
.020
.025
.025
.025
.030
.035
.040
.045
.050
.055
Nominal
mm.
0.40
0.43
0.50
0.50
0.50
0.64
0.64
0.64
0.76
0.88
1.01
1.14
1.27
1.39
SPECIFICATION RT-1171 ISSUE 7
Page 5
TABLE 3
Requirements
PROPERTY
PHYSICAL
Dimensions
Longitudinal Change
Tensile Strength
Ultimate Elongation
Secant Modulus (Expanded)
Concentricity (Expanded)
Restricted Shrinkage
30 minutes at 175 ± 2°C
(347 ± 4°F)
Proof Voltage 2000 V/a-c
Specific Gravity (Recovered)
Low Temperature Flexibility
4 hours at -55 ± 3°C
(-67 ± -5°F)
Heat Shock
4 hours at 250 ± 3°C
(482 ± 5°F)
Heat Resistance
168 hours at 175 ± 2°C
(347 ± 4°F)
Followed by test for:
Tensile Strength
Ultimate Elongation
Color
Color Stability
24 hours at 175 ± 2°C
(347 ± 4°F)
Shore A Hardness
ELECTRICAL
Dielectric Strength
Volume Resistivity
CHEMICAL
Copper Mirror Corrosion
16 hours at 175 ± 2°C
(347 ± 4°F)
Copper Contact Corrosion
16 hours at 175 ± 2°C
(347 ± 4°F)
Flammability
UNIT
REQUIREMENT
TEST METHOD
Inches/(mm)
Percent
psi/(MPa)
Percent
psi/(MPa)
Percent
---
In accordance with Table 1
+0, -5
1500 minimum (10.3)
200 minimum
2.5 x 104 maximum (172)
70 minimum
No Cracks
Section 4.3.1
ASTM D 2671
Section 4.3.2
ASTM D 2671
ASTM D 2671
ASTM D 2671
ASTM D 2671
Procedure A
-----
1.35 maximum
No cracking
ASTM D 2671
Section 4.3.3
Table 2
---
No dripping, flowing or cracking
ASTM D 2671
ASTM D 2671
psi/(MPa)
Percent
-----
1500 minimum (10.3)
200 minimum
MIL-STD-104
MIL-STD-104
MIL-STD-104
ASTM D 2671
85 ± 5
ASTM D 2240
Volts/mil
(volts/mm)
Ohm-cm
500 minimum (19,680)
Note 1
ASTM D 2671
ASTM D 2671
---
Non-Corrosive
ASTM D 2671
Procedure A
---
No pitting or blackening of
copper.
ASTM D 2671
Procedure B
---
1) No flaming or glowing
longer than 1 minute from
any flame application
2) 25% maximum flag burn
3) No burning of cotton.
Self-extinguishing within 15
seconds, no burning or
charring of indicator
ASTM D 2671
Procedure C
1014 minimum
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ASTM D2671
ASTM D 2671
Procedure A
Page 6
SPECIFICATION RT-1171 ISSUE 7
TABLE 3
Requirements
(continued)
PROPERTY
Chemical (continued)
Fungus Resistance
Followed by tests for:
Tensile Strength
Ultimate Elongation
Dielectric Strength
Water Absorption (Recovered)
24 hours at 23 ± 3°C
(73 ± 5°F)
Fluid Resistance
24 hours at 23 ± 3°C
(73 ± 5°F) in:
JP-8 Fuel
(Mil-DTL-83133)
Skydrol* 500
Hydraulic Fluid
(MIL-H-5606)
Aviation Gasoline 100/300
Lubricating Oil
(MIL-L-7808)
Lubricating Oil
(MIL-L-23699)
Deicing Fluid
(MIL-A-8243)
5% NaCl
Followed by tests for:
Dielectric Strength
Tensile Strength
UNIT
REQUIREMENT
TEST METHOD
ISO 846
Method B
psi (Mpa)
percent
Volts per mil
(volts per mm)
---
1500 minimum (10.3)
200 minimum
500 minimum (19,700)
Section 4.3.2
ASTM D 2671
ASTM D 2671
0.5 maximum
ASTM D 2671
---
---
ASTM D 2671
Volts/mil
(volts/mm)
psi (MPa)
400 minimum (15,760)
1000 minimum (6.9)
*Trademark of the Monsanto Company
NOTE 1: Recover the specimens on metal mandrels for 10 minutes, minimum, at 150 ± 3°C (302 ± 5°F) or until the
tubing is completely shrunk on the mandrels.
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