ISO 9938:2022

INTERNATIONAL ISO
STANDARD 9938
Third edition
2022-01
Aerospace — Polytetrafluoroethylene
(PTFE) hose assemblies, classification
204 °C/28 000 kPa — Procurement
specification
Aéronautique et espace — Tuyauteries flexibles en
polytétrafluoroéthylène (PTFE), classification 204 °C/28 000 kPa —
Spécification d'approvisionnement
Reference number
© ISO 2022
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Published in Switzerland
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Contents  Page
Foreword .v
1 Scope . 1
2  Normative references . 1
3  Terms and definitions . 1
4  Requirements . 1
4.1 General . 1
4.2 Qualification . 2
4.3 Materials . 2
4.3.1 General . 2
4.3.2 Metals . 2
4.4 Construction . 2
4.4.1 General . 2
4.4.2 Inner tube . 3
4.4.3 Reinforcement . 3
4.4.4 Fittings . 3
4.5 Inner tube requirements . 3
4.5.1 Density and relative density . 3
4.5.2 Tensile strength . 3
4.5.3 Elongation . 3
4.5.4 Tube roll . 4
4.5.5 Tube proof-pressure . 4
4.5.6 Electrical conductivity . 4
4.6 Hose . 4
4.6.1 Dimensional requirements. 4
4.6.2 Physical requirements. 4
4.6.3 Bore check . 4
4.7 Screw threads . . 4
4.8 Part numbering of interchangeable parts . 4
4.9 Identification of products . 4
4.9.1 General . 4
4.9.2 Fittings . 5
4.9.3 Hose assembly . 6
4.10 Workmanship . 6
4.10.1 General . 6
4.10.2 Dimensions and tolerances . 6
4.10.3 Cleaning . 6
4.11 Hose assembly — Test and performance requirements . 6
4.11.1 Proof pressure . 6
4.11.2 Elongation and contraction . 6
4.11.3 Volumetric expansion . 6
4.11.4 Leakage . 7
4.11.5 Thermal shock . 7
4.11.6 Impulse. 7
4.11.7 Assembly flexibility . 7
4.11.8 Stress degradation . 7
4.11.9 Pneumatic surge . 7
4.11.10 Pneumatic effusion . 8
4.11.11 Repeated installation . 8
4.11.12Burst pressure at room temperature . 9
4.11.13 Electrical conductivity . 9
4.11.14 Fire resistance . 9
5  Quality assurance . 9
5.1 Responsibility for inspection. 9
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5.2 Classification of inspections . 10
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 .12
5.4.3 Sampling tests .12
5.4.4 Periodic control tests .13
5.4.5 Rejection and re-test . .13
5.4.6 Changes in inspection procedures . 13
5.4.7 Destructive test sample .13
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 .
...