ISO 7313:2020

Aircraft - High temperature convoluted hose assemblies in polytetrafluoroethylene (PTFE)

This document specifies characteristics of hose assemblies with corrosion‑resistant metallic braid and convoluted polytetrafluoroethylene (PTFE) inner tube for use in aircraft fluid systems at temperatures between ‑55 °C and +200 °C and at nominal pressures, depending on bore size, up to 6,8 MPa. Special approval from the proper national authority can be required if these hoses are to be part of a pressurized gas storage system. Two types of hose assembly are covered in this document: - Type 1: Non‑conductive inner tube; and - Type 2: Conductive inner tube.

Aéronefs — Tuyauterie flexible, haute température, convolutée, en polytétrafluoréthylène (PTFE)

General Information

• Status: Published
• Publication Date: 19-Mar-2020
• ICS: 49.080 - Aerospace fluid systems and components
• ICS: 83.140.40 - Hoses
• Technical Committee: ISO/TC 20/SC 10 - Aerospace fluid systems and components
• Drafting Committee: ISO/TC 20/SC 10/WG 14 - Hose assemblies
• Current Stage: 9092 - International Standard to be revised
• Start Date: 12-Dec-2025
• Completion Date: 27-Dec-2025

Relations

• Revises: ISO 7313:1984 - Aircraft - High temperature convoluted hose assemblies in polytetrafluoroethylene (PTFE)
• Effective Date: 04-Nov-2015

Overview

ISO 7313:2020 - "Aircraft - High temperature convoluted hose assemblies in polytetrafluoroethylene (PTFE)" specifies requirements for PTFE-lined, convoluted hose assemblies with a corrosion‑resistant metallic braid for use in aircraft fluid systems. The standard covers hose performance and qualification for service temperatures from ‑55 °C to +200 °C and nominal pressures (depending on bore size) up to 6.8 MPa. It distinguishes two types of hose assemblies: Type 1 (non‑conductive inner tube) and Type 2 (conductive inner tube). Special national approval may be required if hoses are used in pressurized gas storage systems.

Key topics and technical requirements

• Materials and construction
  • Convoluted PTFE inner tube combined with corrosion‑resistant metallic braid.
  • Requirements for metals and non‑metallic materials to ensure uniform quality and resistance to corrosion.
• Design and dimensions
  • Specifications for inner tube, reinforcement layers, interlayers and fittings; dimensional tolerances and part numbering for interchangeable parts.
• Performance and testing
  • Qualification and acceptance tests, including:
    • Proof pressure and burst pressure (room and high temperature)
    • Leakage, elongation/contraction
    • Flexibility and vacuum behavior
    • Pressure impulse (fatigue) testing
    • Oil and fuel resistance tests
    • Conductivity test (Type 2 only)
    • Salt corrosion exposure
• Quality assurance and inspection
  • Classification of tests (individual, sampling, periodic control)
  • Inspection methods, preparation of specimens and specified test conditions
• Identification and workmanship
  • Marking and assembly identification, cleaning and protection of openings

Practical applications

ISO 7313:2020 is intended for specification and procurement of high‑temperature PTFE convoluted hoses in aircraft fluid systems, including hydraulic, fuel and other fluid transfer applications where PTFE's chemical and temperature resistance are required. The conductive Type 2 variant addresses situations where electrical continuity/charge dissipation is necessary.

Who uses this standard

• Aerospace OEMs and systems integrators specifying hose assemblies
• Hose and fitting manufacturers seeking qualification and market compliance
• Maintenance, repair and overhaul (MRO) organizations and inspectors
• Procurement and quality engineers responsible for supplier acceptance and testing
• Test laboratories performing aerospace hose qualification and acceptance testing

Related standards

• ISO 756‑1 (referenced in ISO 7313:2020 for test substances)
• Other aerospace fluid system and material test standards (consult national ISO member bodies for applicable cross‑references)

Keywords: ISO 7313:2020, PTFE hose assemblies, high temperature convoluted hose, aircraft fluid systems, metallic braid, Type 1 non‑conductive, Type 2 conductive, aerospace hoses, hose qualification tests.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 7313
Second edition
2020-03
Aircraft — High temperature
convoluted hose assemblies in
polytetrafluoroethylene (PTFE)
Aéronefs — Tuyauterie flexible, haute température, convolutée, en
polytétrafluoréthylène (PTFE)
Reference number
©
ISO 2020
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
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Published in Switzerland
ii © ISO 2020 – All rights reserved

Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Requirements . 1
4.1 Qualification . 1
4.2 Materials . 1
4.2.1 General. 1
4.2.2 Metals . 2
4.2.3 Non-metallic materials . 2
4.3 Design . 2
4.3.1 General. 2
4.3.2 Inner tube . 2
4.3.3 Reinforcement . 2
4.3.4 Interlayers . 2
4.3.5 Fittings . 2
4.4 Dimensions . 2
4.4.1 Hose assembly dimensions . 2
4.4.2 Length. 3
4.5 Performance . 4
4.5.1 General. 4
4.5.2 Examination of product . 4
4.5.3 Proof pressure . 4
4.5.4 Elongation and contraction . 4
4.5.5 Leakage . 4
4.5.6 Room temperature burst pressure . . 4
4.5.7 High temperature burst pressure. 4
4.5.8 Oil resistance . 4
4.5.9 Fuel resistance . 4
4.5.10 Flexibility and vacuum . 4
4.5.11 Pressure impulse . 4
4.5.12 Conductivity (type 2 only) . 4
4.6 Part numbering of interchangeable parts . 5
4.7 Product identification . 5
4.7.1 General. 5
4.7.2 Fittings . 5
4.7.3 Assembly . 5
4.8 Workmanship . 6
4.8.1 General. 6
4.8.2 Dimensions and tolerances . 6
4.8.3 Cleaning . 6
4.8.4 Openings and covers . . 6
5 Quality assurance provisions . 6
5.1 Classification of tests . 6
5.2 Acceptance tests . 6
5.2.1 General. 6
5.2.2 Individual tests . 6
5.2.3 Sampling test . 7
5.2.4 Periodic control test . 7
5.2.5 Rejection and retest. 7
5.3 Qualification testing . 7
5.4 Inspection methods . 9
5.4.1 General. 9
5.4.2 Examination of product .10
5.4.3 Proof pressure test .10
5.4.4 Elongation and contraction test . .10
5.4.5 Leakage test . .10
5.4.6 Room temperature burst pressure test .10
5.4.7 High temperature burst pressure test .10
5.4.8 Oil resistance test .10
5.4.9 Fuel resistance test .11
5.4.10 Flexibility and vacuum test .11
5.4.11 Impulse test .12
5.4.12 Conductivity test .12
5.4.13 Salt corrosion test .13
5.5 Test conditions .13
5.5.1 Preparation of specimens .13
5.5.2 Test fluids .13
5.5.3 Temperature measurements .13
5.5.4 Test pressure .13
6 Ordering data .13
Bibliography .14
iv © ISO 2020 – All rights reserved

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
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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 second edition cancels and replaces the first edition (ISO 7313:1984), which has been technically
revised. The main changes compared to the previous edition are as follows:
— Clause 2, normative references, has been updated;
— the structure of the document has been changed.
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.
INTERNATIONAL STANDARD ISO 7313:2020(E)
Aircraft — High temperature convoluted hose assemblies
in polytetrafluoroethylene (PTFE)
1 Scope
This document specifies characteristics of hose assemblies with corrosion-resistant metallic braid and
convoluted polytetrafluoroethylene (PTFE) inner tube for use in aircraft fluid systems at temperatures
between -55 °C and +200 °C and at nominal pressures, depending on bore size, up to 6,8 MPa. Special
approval from the proper national authority can be required if these hoses are to be part of a pressurized
gas storage system.
Two types of hose assembly are covered in this document:
— Type 1: Non-conductive inner tube; and
— Type 2: Conductive inner tube.
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 756-1, Propan-2-ol for industrial use — Methods of test — Part 1: General
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 https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
4 Requirements
4.1 Qualification
The hose assemblies furnished in accordance with this document shall be a product identical to that
which has passed the qualification tests herein and shall be suitable for use in aircraft fluid systems
under the conditions specified herein.
4.2 Materials
4.2.1 General
The hose assemblies shall be uniform in quality and free from defects in material as is consistent with
good manufacturing practice. Materials shall conform to applicable specifications and the requirements
specified herein.
4.2.2 Metals
Metals shall be of corrosion-resistant type or be suitably treated to resist corrosion due to fluid being
conveyed and/or salt spray and atmospheric conditions to which the hose assembly can be subjected
when in storage or during normal service use.
4.2.3 Non‑metallic materials
All materials used in the hose assemblies shall be "non-ageing" for storage and shall be compatible with
system fluids and other hose assembly materials and suitable for the service intended.
4.3 Design
4.3.1 General
The hose assembly shall consist of a convoluted PTFE inner tube which may be covered with
convoluted woven glass cloth and other suitable material. The convoluted PTFE inner tube may also be
reinforced with stainless steel wire braid and with end fittings suitable for the intended installation.
This document shall specifically cover the hose assembly made up of the specified hose and the hose
attachment mechanism of the fitting.
4.3.2 Inner tube
The inner tube shall be of convoluted construction designed to promote easy bending. It shall be free
from pitting or projections on the inner surface which can interfere with fluid flow.
4.3.3 Reinforcement
The reinforcement shall consist of a stainless-steel wire braid or braids of sufficient strength and
corrosion resistance to meet the requirements of this document.
4.3.4 Interlayers
Interlayers, if used, shall be of suitable material.
4.3.5 Fittings
The fittings shall be specifically designed for this hose and materials shall be selected for the specific
operating conditions. When the requirements for these fittings and this document conflict, this
document shall take precedence.
4.4 Dimensions
4.4.1 Hose assembly dimensions
The dimensions of the hose assemblies shall be in accordance with Table 1.
2 © ISO 2020 – All rights reserved

Table 1 — Hose assembly dimensions
Key
A  diameter of the nipple
B  inside diameter of the inner tube
C  outside diameter of the reinforcement
D  outside diameter of the socket
Dimensions in millimetres
DN A B C D
Hose size minimum minimum maximum maximum
06 3,0 4,8 11,3 14,0
10 6,0 8
...