ISO 8829-2:2006

INTERNATIONAL ISO
STANDARD 8829-2
First edition
2006-09-15
Aerospace — Test methods for
polytetrafluoroethylene (PTFE) inner-tube
hose assemblies —
Part 2:
Non-metallic braid
Aéronautique et espace — Méthodes d'essai des tuyauteries flexibles
à tube intérieur en polytétrafluoroéthylène (PTFE) —
Partie 2: Tuyauteries à gaine non métallique

Reference number
©
ISO 2006
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©  ISO 2006
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ii © ISO 2006 – All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 2
4 Test temperature. 2
5 Tests on PTFE inner tubes . 2
5.1 Density and relative density . 2
5.2 Tensile tests . 2
5.3 Rolling and proof-pressure tests . 4
5.4 Electrical conductivity test . 6
6 Test on hoses and hose assemblies . 6
6.1 Stress degradation test. 6
6.2 Pneumatic effusion test . 8
6.3 Electrical conductivity test . 9
6.4 Visual and dimensional inspection. 10
6.5 Determination of elongation or contraction. 10
6.6 Volumetric expansion test . 10
6.7 Leakage test . 12
6.8 Proof-pressure test. 12
6.9 Burst-pressure tests. 12
6.10 Impulse test . 13
6.11 Flexure test. 13
6.12 Fuel resistance test . 15
6.13 Low-temperature flexure testing . 15
6.14 Pneumatic leakage test . 15
6.15 Vacuum test. 15
6.16 Pneumatic surge test. 16
6.17 Thermal shock test . 16
6.18 Light-radiation aging . 17
6.19 Push-pull test . 18
6.20 Fire test . 19
Annex A (informative) Test fluids . 20
Bibliography . 21

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
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International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 8829-2 was prepared by Technical Committee ISO/TC 20, Aircraft and space vehicles, Subcommittee
SC 10, Aerospace fluid systems and components.
ISO 8829-2 cancels and replaces ISO 8829:1990, which has been technically revised.
ISO 8829 consists of the following parts, under the general title Aerospace — Test methods for polytetra-
fluoroethylene (PTFE) inner-tube hose assemblies:
⎯ Part 1: Metallic (stainless steel) braid
⎯ Part 2: Non-metallic braid
iv © ISO 2006 – All rights reserved

Introduction
This part of ISO 8829 is intended to standardize the test methods for qualification of polytetrafluoroethylene
(PTFE) hose and hose assemblies used in aircraft fluid systems. The tests are intended to simulate the most
strenuous demands encountered in aircraft. Compliance with these test methods is necessary for hose and
hose assemblies which are used in systems where a malfunction could affect the safety of flight.

INTERNATIONAL STANDARD ISO 8829-2:2006(E)

Aerospace — Test methods for polytetrafluoroethylene (PTFE)
inner-tube hose assemblies —
Part 2:
Non-metallic braid
1 Scope
This part of ISO 8829 specifies test methods for flexible polytetrafluoroethylene (PTFE) inner tubes with
non-metallic braided hose and hose assemblies used in aircraft fluid systems, in the pressure and
temperature ranges covered by pressure classes and temperature types, as specified in ISO 6771.
This part of ISO 8829 applies to the hose and the hose coupling. The tests and assembly requirements for the
connecting end fittings are covered in the procurement specification.
This part of ISO 8829 is applicable when reference is made to it in a procurement specification or other
definition document.
NOTE Fluids used for the tests are listed in Annex A.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 2685:1998, Aircraft — Environmental test procedure for airborne equipment — Resistance to fire in
designated fire zones
1)
ISO 6771 , Aerospace — Fluid systems and components — Pressure and temperature classifications
ISO 6772:1988, Aerospace — Fluid systems — Impulse testing of hydraulic hose, tubing and fitting
assemblies
ISO 6773:1994, Aerospace — Fluid systems — Thermal shock testing of piping and fittings
ISO 7258:1984, Polytetrafluoroethylene (PTFE) tubing for aerospace applications — Methods for the
determination of the density and relative density

1) To be published. (Revision of ISO 6771:1987)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
fire sleeve
flame- and heat-retardant element, normally tubular, slipped over the hose assembly and fastened to the hose
fitting
3.2
fire-cover
flame- and fire-retardant element, normally (silicone) rubber, moulded over the hose and hose fittings
4 Test temperature
Unless otherwise specified, tests shall be conducted between 15 °C and 32 °C (59 °F and 90 °F).
5 Tests on PTFE inner tubes
5.1 Density and relative density
5.1.1 Principle
The test is intended to control the crystallinity of PTFE inner tubes.
5.1.2 Test methods
The relative density of the PTFE tubing shall be measured in accordance with ISO 7258:1984, method A or
method B. The density of the PTFE tubing shall be measured in accordance with ISO 7258:1984, method C.
5.2 Tensile tests
5.2.1 Principle
This test is intended to determine the mechanical properties of the PTFE tubing.
5.2.2 Test conditions
Test specimens shall be conditioned for at least 2 h at room temperature prior to testing.
5.2.3 Apparatus
5.2.3.1 Testing machine
The test shall be carried out using a power-driven machine which is capable of maintaining a uniform rate of
jaw separation at 50 mm/min (2 in/min) and which has a suitable dynamometer and a device for measuring
the force applied within ± 2 %. If the capacity range cannot be changed during a test, as in the case of
pendulum dynamometers, the force applied at breaking point shall be measured within ± 2 %, and the
smallest tensile force measured shall be accurate to within ± 10 %. If the dynamometer is of the compensating
type for measuring tensile stress directly, means shall be provided to make adjustments for the cross-
sectional area of the test specimen. The response of the recorder shall be sufficiently rapid for the force
applied to be measured accurately during the elongation of the test specimen to breaking point. If the test
machine is not equipped with a recorder, a device shall be provided that indicates, after fracture, the
maximum force applied during elongation. Testing machines shall be capable of measuring elongation in
increments of 10 %.
2 © ISO 2006 – All rights reserved

5.2.3.2 Micrometer
The micrometer used for measuring flat test specimen thickness shall be capable of exerting a pressure of
25 kPa ± 5 kPa (3,63 psi ± 0,7 psi) on the test specimens, and of measuring the thickness to within
± 0,025 mm (0,001 in).
Dial micrometers exerting either a force of 0,8 ± 0,15 N (0,18 lbf ± 0,034 lbf) on a circular foot 6,35 mm
(0,25 in) in diameter or a force of 0,2  ± 0,04 N (0,045 lbf ± 0,009 lbf) on a circular foot 3,2 mm (0,125 in) in
diameter conform to the pressure requirement specified above. A micrometer should not be used to measure
the thickness of test specimens narrower in width than the diameter of the foot, unless the contact pressure is
properly adjusted.
5.2.4 Calibration of testing machine
The testing machine shall be calibrated.
If the dynamometer is of the strain-gauge type, the test machine shall be calibrated at one or more forces at
regular intervals.
5.2.5 Test specimens
The specimens shall be in accordance with Figure 1.
NOTE Ca
...