BRITISH STANDARD

Specification for

Rubber hoses and hose
assemblies for
automotive air
pressure braking
systems

UD C 62 9. 3. 02 - 592 . 5: 62 - 462 - 036. 4

BS AU 110a:
1995


BS AU 110a:1995

Committees responsible for this
British Standard
The p rep aration of this Britis h S tandard was entrusted b y Technical
C ommittee PRI/66, H os es , to S ub committee PRI/66/2 , H os es and tub ing for
internal comb ustion engines, up on which the following b odies were
rep resented:

British Rub b er Manufacturers’ As sociation Ltd.
LP Gas As sociation
Minis try of D efence
S ociety of Motor Manufacturers and Traders Limited
C o- op ted Memb ers

This Britis h S tandard, having
b een p rep ared under the
direction of the S ector Board for
Materials and C hemicals , was
p ub lis hed under the authority
of the S tandards Board and
comes into effect on
1 5 D ecemb er 1 9 9 5

© BS I 0 7- 1 9 9 9

Firs t p ub lis hed O ctob er 1 9 65
S econd edition D ecemb er 1 9 9 5

The following BS I references
relate to the work on this
s tandard:
C omm ittee reference PRI /6 6/2
D raft for com ment 9 4/3 02 46 6 D C

ISBN 0 580 24682 5

Amendments issued since publication
Amd. No.

D ate

C omments



BS AU 110a:1995

Contents
Page
Committees responsible
Foreword

ii

1

Scope

1

2

References

1

3

Definition

1

4

Types


1

5

Construction

1

6

Dimensions and tolerances

1

7

Conditioning

1

8

Performance

2

9

Marking


2

Annex A (normative) Ageing test

3

Annex B (normative) Leakage under pressure

3

Annex C (normative) Flexure test

4

Figure A. 1 — Hose positioning for ageing test

3

Figure C. 1 — Curved hose

4

Figure C. 2 — Flexure test

5

Table 1 — Dimensions and tolerances of diameters

1


Table 2 — Minimum bend radius

1

Table A. 1 — Dimensions of hose test pieces and former

3

Table C. 1 — Dimensions for flexure test

5

List of references

© BSI 07- 1 999

Inside front cover

Inside back cover

i


BS AU 1 1 0 a: 1 995

Fore word

This British Standard has been prepared by Subcommittee PRI/66/2. It
supersedes BS AU 1 1 0: 1 965, which is withdrawn.

This revision brings the specification broadly into line with SAE J1 402 [1 ] , a
specification to which a proportion of this type of hose is manufactured in the UK,
but this British Standard specifies higher operating temperatures.
The specification has been improved by the addition of several tests and more
stringent requirements so that the standard more accurately reflects current
demands and the product is better able to carry out its safety critical function.
A British Standard does not purport to include all the necessary provisions of a
contract. Users of British Standards are responsible for their correct application.
C omp liance with a British S tand ard d oe s no t of itse lf confe r immunity
from le gal ob ligatio ns.

S ummary of p age s

This document comprises a front cover, an inside front cover, pages i and ii,
pages 1 to 6, an inside back cover and a back cover.
This standard has been updated (see copyright date) and may have had
amendments incorporated. This will be indicated in the amendment table on the
inside front cover.

ii

© BSI 07- 1 999


BS AU 1 1 0 a: 1 995

c) a rubber cover resistant to oil and
hydrocarbons,
ageing and ozone.
This British Standard specifies the dimensions,

The
lining
and
cover
shall be free from holes,
construction and performance requirements for two
porosity
and
other
defects.
types of hose and hose assemblies used in all parts
NOTE The hoses may be either mandrel or non-mandrel made
of air pressure brake systems.
and finished smooth or fabric marked.
1 S cop e

NOTE Both types are designed for operation at a maximum
working pressure of 15.5 bar, and are distinguished by their
recommended temperature ranges of operation.

6 D imensions and tole rance s
6 . 1 D iame te rs

2 Re fe re nce s
2 . 1 Normative re fe re nce s

This British Standard incorporates, by dated or
undated reference, provisions from other
publications. These normative references are made
at the appropriate places in the text and the cited

publications are listed on the inside back cover. For
dated references, only the edition cited applies; any
subsequent amendments to or revisions of the cited
publication apply to this British Standard only
when incorporated in the reference by amendment
or revision. For undated references, the latest
edition of the cited publications applies, together
with any amendments.

When measured in accordance with BS EN 24671
the internal and external diameters shall be as
given in Table 1.
6 . 2 Limits on cut le ngths of hose

NOTE The nominal length of hose should be specified by the
purchaser.

When measured in accordance with BS 5173-101.2
the tolerance on cut lengths shall be ± 1 % of the
nominal length.
6 . 3 Minimum b e nd rad ius

The minimum bend radius for installation shall be
as given in Table 2.
Tab le 1 — D ime nsions and to le rance s o f

2 . 2 Informative re fe re nce s

This British Standard refers to other publications
that provide information or guidance. Editions of

these publications current at the time of issue of this
standard are listed on the inside back cover, but
reference should be made to the latest editions.
3 D e finitions

For the purposes of this British Standard the
definitions given in BS 3558 apply, together with
the following.

d iame te rs

Dimensions in millimetres
No mi nal

To le rance

No mi nal

To le rance

i nte rnal

o n i nte rnal

e xte rnal

o n e xte rnal

d i ame te r


d i ame te r

d iame te r

d i ame te r

6.3
10.0
12.5
14.0
16.0

hose asse mb ly

hose with either permanent or reusable end fittings
attached
4 Typ e s

There are two types of hose for use within the
following temperature ranges:
a) type A; for use within the temperature
range – 40 °C to + 125 °C;
b) type B; for use within the temperature
range – 40 °C to 150 °C.

0.40
± 0.40
± 0.50
± 0.50
± 0.50


16.0
19.0
22.2
25.4
27.0

±

0.50
± 0.50
± 0.60
± 0.60
± 0.60
±

Tab le 2 — Minimum b e nd radius

Dimensions in millimetres
No mi nal i nte rnal d i ame te r

6.3
10.0
12.5
14.0
16.0

Mini mu m b e nd rad i u s

64

89
102
108
114

7 C onditioning

Tests given in to
shall be carried out on test
pieces taken from hoses or hose assemblies that
have undergone the following water immersion
The hoses shall consist of:
a) a rubber lining with smooth bore and resistant conditioning.
The hose or hose assembly shall be immersed in
to oil;
distilled water at (23 ± 2) °C for (168 ± 2) h while
b) a textile reinforcing layer or layers, plied,
bent to the minimum bend radius given in Table 2.
braided or spirally wound;
The hose ends and couplings shall be completely
capped during immersion.
8. 1

8. 1 1

5 C onstruction

© BSI 07-1999

1



BS AU 1 1 0a:1 995

8 Performance
8.1 Resistance to ageing

When tested in accordance with Annex A, the hose
shall show no signs of cracking, charring or
disintegration, either internally or externally.
8.2 Low temperature flexibility

When tested in accordance with method B of
BS EN 24672:1993 at a temperature
of (– 40 ± 2) °C, the hose shall show no signs of
cracking when examined visually, and shall
conform to 8.4 .
8.3 Change in length

When tested in accordance with BS 5173-101.2,
using an applied pressure of 15.5 bar1) , the
maximum change in length shall be in the
range – 7 % to + 5 %.
8.4 Proof pressure test

when tested in accordance with BS 5173-102.1 the
hose or hose assembly shall not leak or show signs
of failure at a hydrostatic pressure of 31 bar.

8.8 Adhesion


When tested in accordance with BS EN 28033, the
load required to separate any layers shall be a
minimum of 1.4 kN/m.
8.9 Ozone resistance

When tested in accordance with method 1 of
BS EN 27326:1993, no cracking shall be visible
when the test specimen is examined
under 2 × magnification.
8.1 0 Neutral salt spray test (applies to hose
assemblies only)

When tested in accordance with BS 7479
for (96 ± 2) h, the hose assembly shall show no base
metal corrosion.
8.1 1 Flexure test (applies to hose assemblies
only)

When tested in accordance with Annex C the hose
assembly shall not fail before one million flex cycles
have been completed.
9 Marking

Each length of hose shall be durably marked at
when tested in accordance with BS 5173-102.1 the intervals of not more than 250 mm with the
hose or hose assembly shall not burst, leak or show following information:
signs of failure at a hydrostatic pressure less
a) manufacturer’s name or identification;
than 62 bar.

b) number of this British Standard; 2)
8.6 Air leak
c) type (A or B);
When tested in accordance with Annex B the hose or
d) nominal internal diameter;
hose assembly shall show no leakage on visual
e) quarter and year of manufacture;
examination.
f) description “Air brake”;
8.7 Swell test
g) batch reference number.
A test piece taken from both the lining and cover
after immersion in oil no. 3 in accordance with
BS 903-A16 at (100 ± 2) °C for (70 ± 2) h shall show MR/BSAU110a/A/16/3Q95/AIR BRAKE/BBB
a volume increase of not more than 100 %.
8.5 Burst pressure test

Example:

1) 1 bar = 100 kPa
2) Marking BS AU 110a:1995 on or in relation to a product represents a manufacturer’s declaration of conformity, i.e. a claim by

or on behalf of the manufacturer that the product meets the requirements of the standard. The accuracy of the claim is solely the
claimant’s responsibility. Such a declaration is not to be confused with third party certification of conformity, which may also be
desirable.

2

© BSI 07-1999



BS AU 1 1 0a:1 995

Annex A (normative)
Ageing test

A.2 Procedure
Bend a length of hose around a former of the
dimensions specified in Table A. 1 and hold in place

A.1 Air oven (see BS 903- A1 9)

by a band or cord (see Figure A. 1 ) .

The internal dimensions of the air oven shall not

Place the assembly in the oven at the appropriate

exceed (1 × 1 × 1 . 5) m. No copper or copper alloy

temperature shown below for a period of (70 ± 2) h:

shall be within the ageing chamber. Provision shall

type A 1 25 ° C

be made for suspending test pieces so that they are

type B 1 50 ° C


not within 1 cm of each other or of the sides of the

After the ageing period take the assembly from the

oven.
There shall be a slow circulation of air through the
oven of not less than three changes in one hour. The
incoming air shall be heated to the temperature of
the oven before coming into contact with the test
pieces.

oven, allow it to cool to room temperature and
remove the hose from the former. Open out the hose
to a straight length and cut lengthwise for
examination.

Annex B (normative)
Leakage under pressure

Means shall be provided for controlling and
measuring the rate of air flow.
The temperature of the oven shall be

Connect the hose assembly, capped at one end, to a

thermostatically controlled so that the test pieces

source of air pressure. Submerge the assembly in

are kept within 1 °C of the relevant ageing


water, using any suitable container for the water

temperature specified in A.2 . A thermometer shall

such that visual observation of the assembly is

be placed amongst the test pieces to indicate the

possible.

actual ageing temperature.

Apply an internal air pressure of 1 5. 5 bar to the
hose, maintaining the air pressure for at
least 5 min. Examine visually for leaks.

Table A.1 — Dimensions of hose test pieces and former
Dimensions in millimetres

Dimensions of test specimen
Nominal internal diameter of

Dimensions of former

Length of hose

Radius

Height


R

hose

Width

A

B

Thickness

C

6. 3

229

38

114

76

13

1 0. 0

254


45

1 20

89

19

1 2. 5

279

51

1 27

1 02

19

1 4. 0

305

57

1 40

114


22

1 6. 0

305

57

1 40

114

22

Figure A.1 — Hose positioning for ageing test

© BSI 07- 1 999

3


BS AU 1 1 0a:1 995

Annex C (normative)
Flexure test

b) After fitting has been coupled with the movable
manifold, connect the fitting to the stationary
manifold, X, without imparting any twist to the

hose, but allowing the hose to seek its natural

C.1 Preparation of test pieces
C.1 .1 Prior to cutting the hose, apply a layline (of a
colour distinguishable from that of the hose cover)

curvature.

C.4 Test procedure

along the length of the hose following the natural

Flexure/pressure cycling test parameters shall be as

hose curvature which results from the hose being

follows:

coiled in a roll (see Figure C. 1 ).

a) total flexure stroke (1 52 ± 1 . 6) mm;

C.1 .2 Cut the hose to provide a hose assembly test
piece with a free hose length as shown in Table C. 1 .
Free hose length is the outside exposed hose length
between the fittings in the finished hose assembly.

C.1 .3 Assemble fittings to the hose in accordance
with the manufacturer’s instructions.


to 27 °C;
d) internal air pressure on test
samples (1 0. 3 ± 0. 1 ) bar.
Flex the test pieces by moving fitting from the

C.2 Preconditioning
Subj ect each hose test piece assembly to the neutral
salt spray test described in 8.1 0 followed by heat
ageing in an oven at (1 00 ± 1 ) ° C for (70 ± 2) h with
the hose assembly in a straight position.

C.3 Installation of test pieces in the test set up
After preconditioning, install the assembly as
shown in Figure C. 2 and proceed as follows, using
configuration dimensions given in Table C. 1 .
a) With the movable manifold, Y, of the flex test
machine at the centre of its stroke, connect fitting
to the movable manifold in such a manner that
the layline is located at the top- centre position
(see Figure C. 2).

b) flexure stroke frequency (1 00 ± 5) cycles/min;
c) ambient temperature in the range 21 ° C

centre stroke position to 76 mm either side of centre
(“A” dimension in Figure C. 2) alternating between
positions “1 ” and “2” while simultaneously cycling
the air pressure on for 60 s and off for 60 s.
The air pressure shall be alternately fully “on”
for (60 ± 5) s and fully “off” for (60 ± 5) s.


C.5 Failure point
The failure point shall be determined by loss of air
pressure through the failed test piece. As the air
pressure is alternately fully “on” for 60 s and fully
off for 60 s, pressure loss shall be further described
as failure of the system to be repressurized
to (1 0. 3 ± 0. 7) bar through a ( 1 . 6

+0. 03
0. 00

mm ) diameter

orifice within 1 20 s.

Figure C.1 — Curved hose

4

© BSI 07- 1 999


BS AU 1 1 0 a: 1 995

Figure C . 2 — Fle xure te st

Tab le C . 1 — D ime nsio ns for fle xure te st

Dimensions in millimetres

No mi nal inte rnal

Fre e ho se le ngth

C o nfi gu ratio n/d i me nsio ns

± (1 . 6 mm)

d iame te r

Po si ti o n 1

A
6. 3

B

Po si tio n 2

C

R

a

A

B

C


R

254

76

70

95

34

76

70

95

30

10

279

76

89

114


43

89

89

114

33

1 2. 5

355

76

1 02

1 27

56

1 02

1 02

1 27

46


a

1 4. 0
1 6. 0
a

This is an approximate average radius.

© BSI 07- 1 999

5


6

blank


BS AU 110a:1995

List of references

(see clause

2)

Normative references
BSI publications
BRITISH STANDARDS INSTITUTION, London


BS 903, Physical testing of rubber.
BS 903- A1 6: 1 987, Determination of the effect of liquids.
BS 903- A1 9: 1 986, Heat resistance and accelerated ageing tests.
BS 3558: 1 980, Glossary of rubber terms.
BS 51 73, Methods of test for rubber and plastics hoses and hose assemblies.
BS 51 73- 1 01 , Determination of dimensions.
BS 51 73- 1 01 . 2: 1 987, Measurement of length of hoses and hose assemblies.
BS 51 73- 1 02, Hydraulic pressure tests.
BS 51 73- 1 02. 1 : 1 991 , Hydrostatic tests.
BS 7479: 1 991 , Method for salt spray corrosion tests in artificial atmospheres.
BS EN 24671 : 1 993, Rubber and plastics hose and hose assemblies — Methods of measurement of
dimensions.

BS EN 24672: 1 993, Rubber and plastics hoses — Sub-ambient temperature flexibility tests.
BS EN 27326: 1 993, Rubber and plastics hoses — Assessment of ozone resistance under static conditions.
BS EN 28033: 1 993, Rubber and plastics hose — Determination of adhesion between components.

Informative references
Other publications
[1 ] SAE J 1 402, Automatic air brake hose and hose assemblies

3)

3)

.

Published by the Society of Automobile Engineers, 400 Commonwealth Drive, Warrendale PA 1 5096- 0001 USA


© BSI 07- 1 999


BS AU 110a:
1995

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