ISO/DIS 9528

Aerospace -- Standard-weight polytetrafluoroethylene (PTFE) hose assemblies, classification 204 °C/21 000 kPa -- Procurement specification

Aéronautique et espace -- Tuyauteries flexibles en polytétrafluoroéthylène (PTFE), série normale, classification 204 °C/21 000 kPa -- Spécification d'approvisionnement

Standards Content (sample)

DRAFT INTERNATIONAL STANDARD
ISO/DIS 9528
ISO/TC 20/SC 10 Secretariat: DIN
Voting begins on: Voting terminates on:
2020-09-16  2020-12-09
Aerospace — Standard-weight polytetrafluoroethylene
(PTFE) hose assemblies, classification 204 °C/21 000 kPa
— Procurement specification

Aéronautique et espace — Tuyauteries flexibles en polytétrafluoroéthylène (PTFE), série normale,

classification 204 °C/21 000 kPa — Spécification d'approvisionnement
ICS: 49.080; 83.140.40
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
This document is circulated as received from the committee secretariat.
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 9528:2020(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. ISO 2020
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ISO/DIS 9528:2020(E)
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© ISO 2020

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ii © ISO 2020 – All rights reserved
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ISO/DIS 9528:2020(E)
Contents  Page

Foreword ..........................................................................................................................................................................................................................................v

1  Scope .................................................................................................................................................................................................................................1

2  Normative references ......................................................................................................................................................................................1

3  Terms and definitions .....................................................................................................................................................................................1

4  Requirements ..........................................................................................................................................................................................................2

4.1 Qualification .............................................................................................................................................................................................. 2

4.2 Materials ....................................................................................................................................................................................................... 2

4.2.1 General...................................................................................................................................................................................... 2

4.2.2 Metals ........................................................................................................................................................................................ 2

4.3 Construction .............................................................................................................................................................................................. 2

4.3.1 General...................................................................................................................................................................................... 2

4.3.2 Inner tube .............................................................................................................................................................................. 3

4.3.3 Reinforcement .................................................................................................................................................................... 3

4.3.4 Fittings ...................................................................................................................................................................................... 3

4.4 Inner tube .................................................................................................................................................................................................... 3

4.4.1 Density and relative density .................................................................................................................................. 3

4.4.2 Tensile strength ................................................................................................................................................................ 3

4.4.3 Elongation .............................................................................................................................................................................. 3

4.4.4 Tube roll .................................................................................................................................................................................. 3

4.4.5 Tube proof-pressure ..................................................................................................................................................... 4

4.4.6 Electrical conductivity ................................................................................................................................................ 4

4.5 Hose .................................................................................................................................................................................................................. 4

4.5.1 Dimensional requirements ..................................................................................................................................... 4

4.5.2 Physical requirements ................................................................................................................................................ 4

4.5.3 Bore check ............................................................................................................................................................................. 4

4.6 Screw threads........................................................................................................................................................................................... 4

4.7 Part numbering of interchangeable parts ....................................................................................................................... 4

4.8 Identification of products .............................................................................................................................................................. 4

4.8.1 General...................................................................................................................................................................................... 4

4.8.2 Fittings ...................................................................................................................................................................................... 6

4.8.3 Hose assembly ................................................................................................................................................................... 6

4.9 Workmanship ........................................................................................................................................................................................... 6

4.9.1 General...................................................................................................................................................................................... 6

4.9.2 Dimensions and tolerances ..................................................................................................................................... 6

4.9.3 Cleaning ................................................................................................................................................................................... 6

4.10 Hose assembly — Test and performance requirements ..................................................................................... 6

4.10.1 Proof pressure .................................................................................................................................................................... 6

4.10.2 Elongation and contraction .................................................................................................................................... 6

4.10.3 Volumetric expansion .................................................................................................................................................. 6

4.10.4 Leakage .................................................................................................................................................................................... 7

4.10.5 Thermal shock ................................................................................................................................................................... 7

4.10.6 Impulse ..................................................................................................................................................................................... 7

4.10.7 Assembly flexibility ....................................................................................................................................................... 7

4.10.8 Stress degradation .......................................................................................................................................................... 7

4.10.9 Pneumatic surge ............................................................................................................................................................... 7

4.10.10 Pneumatic effusion ........................................................................................................................................................ 9

4.10.11 Repeated installation ................................................................................................................................................... 9

4.10.12 Burst pressure at room temperature ............................................................................................................. 9

4.10.13 Electrical conductivity ................................................................................................................................................ 9

4.10.14 Fire resistance .................................................................................................................................................................... 9

5  Quality assurance .............................................................................................................................................................................................10

5.1 Responsibility for inspection ...................................................................................................................................................10

5.2 Classification of inspections .....................................................................................................................................................10

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ISO/DIS 9528:2020(E)

5.3 Qualification inspections .............................................................................................................................................................10

5.3.1 Qualification test samples .....................................................................................................................................10

5.3.2 Test report, test samples and data for the purchaser ...................................................................10

5.3.3 Qualification testing ...................................................................................................................................................12

5.3.4 Criteria for requalification ....................................................................................................................................12

5.4 Quality conformance inspections ........................................................................................................................................12

5.4.1 General...................................................................................................................................................................................12

5.4.2 Individual tests ...............................................................................................................................................................13

5.4.3 Sampling tests .................................................................................................................................................................13

5.4.4 Periodic control tests ................................................................................................................................................13

5.4.5 Rejection and re-test..................................................................................................................................................14

5.4.6 Changes in inspection procedures .................................................................................................................14

5.4.7 Destructive test sample ...........................................................................................................................................14

5.5 Test conditions .....................................................................................................................................................................................14

5.5.1 Assembly, ends and hose........................................................................................................................................14

5.5.2 End connections ............................................................................................................................................................14

5.5.3 Test fluids ............................................................................................................................................................................14

5.5.4 Temperature measurements ..............................................................................................................................14

5.5.5 Pressure measurements .........................................................................................................................................15

5.5.6 Preparation of test specimens ...........................................................................................................................15

5.6 Inspection methods .........................................................................................................................................................................15

5.6.1 Examination of product ..........................................................................................................................................15

6  Preparation for delivery ............................................................................................................................................................................15

6.1 Storage and packaging ...................................................................................................................................................................15

6.2 Marking ......................................................................................................................................................................................................15

7 Ordering data ........................................................................................................................................................................................................15

Annex A (informative) Equivalent components .....................................................................................................................................17

iv © ISO 2020 – All rights reserved
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ISO/DIS 9528:2020(E)
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 non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

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. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 20, Aircraft and space vehicles,

Subcommittee SC 10, Aerospace fluid systems and components.

This third edition cancels and replaces the second edition (ISO 9528:1994), which has been technically

revised.
The main changes compared to the previous edition are as follows:
— clause 2, Normative references, was updated;
— references in the whole document were updated;
— column "Material No." was added to Table 1;
— note in 4.3.4.1 General (Fittings) was deleted;
— Annex A now only contains the equivalent components.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
© ISO 2020 – All rights reserved v
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DRAFT INTERNATIONAL STANDARD  ISO/DIS 9528:2020(E)
Aerospace — Standard-weight polytetrafluoroethylene
(PTFE) hose assemblies, classification 204 °C/21 000 kPa
— Procurement specification
1  Scope

This document specifies requirements for standard-weight polytetrafluoroethylene (PTFE) hose

assemblies for use in aircraft hydraulic systems at temperatures between –55 °C and +204 °C and at

a nominal pressure up to 21 000 kPa (210 bar). The hose assemblies are also suitable for use within

the same temperature and pressure limitations in aircraft pneumatic systems where some gaseous

diffusion through the wall of the PTFE liner can be tolerated.

The use of these hose assemblies in high-pressure pneumatic storage systems is not recommended.

In addition, installations in which the limits specified in this document are exceeded, or in which the

application is not covered specifically by this document, for example for oxygen, shall be subject to the

approval of the purchaser.
2  Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements 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, Aircraft — Environmental test procedure for airborne equipment — Resistance to fire in

designated fire zones

ISO 2859-1, Sampling procedures for inspection by attributes — Part 1: Sampling plans indexed by

acceptable quality level (AQL) for lot-by-lot inspection

ISO 5855-3, Aerospace — MJ threads — Part 3: Limit dimensions for fittings for fluid systems

ISO 6772, Aerospace — Fluid systems — Impulse testing of hydraulic hose, tubing and fitting assemblies

ISO 7258, Polytetrafluoroethylene (PTFE) tubing for aerospace applications — Methods for the

determination of the density and relative density

ISO 8829-1:2009, Aerospace — Test methods for Polytetrafluoroethylene (PTFE) inner-tube hose

assemblies — Part 1: Metallic (stainless steel) braid
3  Terms and definitions
No terms and definitions are listed in this document.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at http:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
© ISO 2020 – All rights reserved 1
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ISO/DIS 9528:2020(E)
4  Requirements
4.1  Qualification

Hose assemblies supplied in accordance with this document shall be representative of products which

have been subjected to and which have successfully passed the requirements and tests specified in this

document.
4.2  Materials
4.2.1  General

The hose assembly materials shall be as described in this document. All materials not specifically

described in this document shall be of the highest quality and suitable for the purpose intended.

4.2.2  Metals

Metals used in the hose and fittings shall be corrosion-resistant or titanium and shall conform to the

applicable specifications described in Table 1.
Table 1 — Metals to be used in hose assemblies
Form Metal Material No.
Austenitic, annealed or as-rolled, corrosion-resistant steel AMS 5639 (304)
AMS 5645 (321)
Austenitic, annealed or as-rolled, stabilized, corrosion-resistant steel
AMS 5646 (347)
Bars
AMS 5643 (17-4),
and
forgings
Precipitation-hardening, corrosion-resistent steel AMS 5644,
AMS 5743
Titanium 6Al-4V AMS 4928 (6-4)

Austenitic, seamless or welded, annealed, corrosion-resistant steel MIL-T-8504 (304)

MIL-T-8808 (321)
Tubing Austenitic, seamless or welded, stabilized, corrosion-resistant steel
MIL-T-8808 (321)
Cold-worked, stress-relieved titanium alloy AMS 4945
AMS 5689
Wire Austenitic, cold-drawn, corrosion-resistent steel AMS 5690
AMS 5697
4.3  Construction
4.3.1  General
The hose assembly shall consist of
— a seamless PTFE inner tube (see 4.3.2),
— corrosion-resistant steel-wire reinforcement (see 4.3.3), and
— corrosion-resistant steel and/or titanium end fittings (see 4.3.4),

as required to meet the construction and performance requirements laid down in this document and as

required for its intended use.
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ISO/DIS 9528:2020(E)
4.3.2  Inner tube

The inner tube shall be of a seamless construction of virgin PTFE resin of uniform gauge; it shall have

a smooth bore and shall be free from pitting or projections on the inner surface. Additives may be

included in the compound from which the tube is extruded with no more than 2 % of such additives

being retained in the mixture.
4.3.3  Reinforcement

The reinforcement shall consist of corrosion-resistant steel wire conforming to the applicable

specifications given in 4.2.2. The wires shall be arranged over the inner tube so as to provide sufficient

strength to ensure compliance with the requirements laid down in this document.

Broken or missing reinforcing wires shall be cause for rejection; crossed-over reinforcing wires shall

not be cause for rejection of the hose assembly.
4.3.4  Fittings
4.3.4.1  General

It shall be proven that all fittings comply with the requirements laid down in this document. Unless

otherwise specified by the purchaser, the hose assemblies shall have flareless fittings (24° cone

coupling).
4.3.4.2  Insert fittings

Insert fittings shall be manufactured in one piece wherever possible; those made of other than one-

piece construction shall be butt-welded, unless otherwise agreed by the purchaser, fabricated from

annealed, austenitic, corrosion-resistant steel tubing. Welded and redrawn tubing may be used.

4.4  Inner tube
4.4.1  Density and relative density

The relative density of the hose inner tube shall not exceed 2,155, when tested in accordance with

ISO 7258, either method A or method B (as specified in ISO 8829-1). The density shall not exceed

2,204 g/cm , when tested in accordance with ISO 7258, method C (as specified in ISO 8829-1).

4.4.2  Tensile strength

When tested in accordance with ISO 8829-1:2009, 4.2, the longitudinal tensile strength for all sizes of

2 1)
tubes shall be at least 15,1 N/mm .

When tested in accordance with ISO 8829-1:2009, 4.2, the transverse tensile strength for sizes DN 16 and

larger shall be at least 12,4 N/mm ; for sizes under DN 16, the transverse strength need not be tested.

4.4.3  Elongation

When tested in accordance with ISO 8829-1:2009, 4.2, the elongation shall be at least 200 %.

4.4.4  Tube roll

The tube shall not leak, split, burst or show any signs of malfunction, when tested through the sequence

as specified in ISO 8829-1:2009, 4.3.2.
1) 1 N/mm = 1 MPa
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ISO/DIS 9528:2020(E)
4.4.5  Tube proof-pressure

After being subjected to the tube roll test sequence (see 4.4.4), the tube, without reinforcing wires, shall

not leak, burst or show any signs of malfunction, when tested as specified in ISO 8829-1:2009, 4.3.3.

4.4.6  Electrical conductivity

When tested in accordance with ISO 8829-1:2009, 4.4, the electrical current shall be equal to or

greater than
a) 10 μA for sizes DN 06 to DN 12 (inclusive);
b) 20 μA for sizes DN 16 and over.
4.5  Hose
4.5.1  Dimensional requirements

The hose assembly dimensions, except for length, shall be as specified in Figure 1 and Table 2.

4.5.2  Physical requirements

Hose assemblies shall comply with the physical and linear density (weight) requirements specified in

Table 3.
4.5.3  Bore check

When bent to the appropriate minimum bend radius as specified in Table 3, the hose assembly shall

permit the free passage of a solid rigid sphere throughout its length. The diameter of the sphere shall

be 90 % of the appropriate minimum internal diameter of the end fittings as specified in Table 2. For

elbow fittings, see Footnote a) in Table 2.
4.6  Screw threads

Unless otherwise specified (see 4.3.4), fitting threads shall be in accordance with ISO 5855-3. A 10 %

increase in the tolerance of the fitting thread of the nut during assembly or testing shall not be cause for

rejection of the hose assembly.
4.7  Part numbering of interchangeable parts

All parts complying with this document and having the same manufacturers or standard part number

shall be functionally and dimensionally interchangeable.
4.8  Identification of products
4.8.1  General
The hose assembly and its component parts shall be permanently marked.
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ISO/DIS 9528:2020(E)
Key
a See footnote b) to Table 2
Figure 1 — Hose and fitting dimensions
Table 2 — Hose and fitting dimensions (see Figure 1)
Dimensions in millimetres
Hose (braided) Fitting
Wall thick-
Inside Inside Outside Attachment
Hose size Outside diameter ness of inner
a b
diameter diameter diameter length
tube
(nom.) d D d D l δ
h h f f
min. min. max. min. max. max. min.
DN 06 5,3 10,2 11,8 3,3 23 58
0,89
DN 10 7,5 13,6 15,1 6,1 26 64
DN 12 9,9 17,1 18,6 8,6 31 70
DN 16 12,3 22,2 23,7 10,4 36 78
DN 20 15,3 26,1 27,7 12,9 43 83
1,1
DN 25 21,6 34,2 35,8 19,3 51 96
DN 32 28 39,6 41,9 23,5 54 99 1,27

Minimum inside diameter through the elbow area may be 85 % of the values given for 4.

Width across corners of nut and socket hexagon may exceed the values given for A.

Table 3 — Physical requirements of hose assemblies and linear density (weight) of hose

Burst pressure
Linear density  Bend radius
Operating Proof Volumetric
(weight) of at Inside of
at room tem- at high tem-
pressure pressure expansion
hose bend
perature perature
Hose size
max. min. min. min. max.
kg/m kPa kPa kPa kPa mm ml/m
DN 06 0,295 76 2,6
DN10 0,5 127 3,4
DN12 0,
...