KENYA STANDARD                             KS 395:2020  
                       ICS 43.060.30  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Rubber automobile radiator hoses —
Specification  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
©KEBS 20 20        Third Edition 2020  
 
  DKS 395:2020                                                                                                        
 
ii                      ©KEBS 2020 — All rights reserved  
 
 TECHNICAL COMMITTEE REPRESENTATION  
 
The following organizations were represented on the Tech nical Committee:  
 
Toyota Kenya Ltd  
D.T Dobie  
Mitsumoto  
Isuzu E.A  
Kenya Association of Bus Manufacturers (KABM)  
Kenya Motor Repairers Association (KEMRA)  
Nissan  
Numerical Machining Complex (NMC)  
Gede Enterprises  
Mobius Motors  
KUMPIA  
Kenya Industrial Researc h and development Institute (KIRDI)  
Technical University of Kenya (TUK)  
Motorwise Valuers  
Kenya Auto Bazaar Association  
Honda (Nairobi)  
Egerton University  
Olive Technical Services Ltd  
Kenya Jua Kali Association  
MCI Ltd  
Kenya Bureau of Standards — Secretari at 
 
 
 
 
 
 
 
 
REVISION OF KENYA STANDARDS  
 
In order to keep abreast of progress in industry, Kenya Standards shall be regularly reviewed. Suggestions 
for improvements to published standards, addressed to the Managing Director, Kenya Bureau of Standards, 
are w elcome.  
 
 
 
 
 
 
 
 
© Kenya Bureau of Standards, 2020  
 
Copyright:  Users are reminded that by virtue of Section 6 of the Copyright Act, Cap. 130 of the Laws of Kenya, copyright sub sists in all 
Kenya Standards and except as provided under Section 7 of this Act,  no Kenya Standard produced by Kenya Bureau of Standards may 
be reproduced, stored in a retrieval system in any form or transmitted by any means without prior permission in writing from the 
Managing Director.  
 
 
 
 
 
 
 
 KENYA STANDARD             DKS 395:2020    
 ©KEBS 2020 — All rights reserved            iii  
 
 
 
 
        ICS 43.060.30  
 
 
 
 
 
 
 
 
 
Rubber automobile radiator hoses —
Specification  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  DKS 395:2020                                                                                                        
 
iv                      ©KEBS 2020 — All rights reserved  
 
  
KENYA BUREAU OF STANDARDS (KEBS)  
 
Head Office:  P.O. Box 54974, Nairobi -00200, Tel.: (+254  020) 605490, 602350, Fax: (+254 020)  604031  
E-Mail: info@kebs.org,  Web:http://www.kebs.org   
 
Coast Region     Lake Region          Rift Valley Region  
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Fax: (+254  041) 229448    Fax: (+254 057) 21814               
 
Foreword  
 
This Kenya Standard was prepared by the Road Vehicles Technical Committee under the guidance of the 
Mechanical Engineering Industry Standards Committee, and it is in accordance with the pro cedures of the 
Bureau.  
 
Considering the importance of the cooling system to the engine of an automobile, it was felt that this 
standard should be prepared to improve the quality of radiator hoses manufactured in this country.  External 
leakage due to defec tive rubber hoses and collapsing radiator hoses causes poor circulation. Leaks occur at 
the hose connections.  Rubber also disintegrates on the inside causing blocking of the coolant, resulting in 
over-heating of the engine.  Bits of rubber from the inside  of the rubber hose can deposit in the engine, which 
can act as an insulator and thus cause engine overheat.  Such engine overheats cost the user a lot of 
money.  Considering that hoses can only be replaced and not repaired, the need for high quality hoses  is 
obvious.  
 
 
 This Third edition cancels and replaces the second edition (KS 06 -395:2012 ), which has been technically 
revised.  
 
During the preparation of this standard, reference was made to the following publication:  
 
 IS 2765, Indian Standard Specifica tion for radiator hoses ( First Revision ).   
 
Acknowledgement is made for the assistance obtained from this source.  
 
 
 
 
 
 
 
 KENYA STANDARD         DKS 395:2020  
©KEBS 2020 — All rights reserved                      1  
 
Rubber automobile radiator hoses — Specification  
 
1 Scope  
 
This Kenya Standard specifies materials and performance requirements  and test methods for automobile 
radiator rubber hoses.  
 
2 Definitions  
 
For the purposes of this standard, the following definitions shall apply:  
 
2.1 
permanent set   
the residual increase in length of a test piece measured after a specified period from the  release of the load 
after subjection to a specified strain applied for a specified period of time, and expressed as a percentage of 
the original length  
 
2.2 
swelling  
the percentage increase in volume which a test piece of given dimensions undergoes when immersed in a 
liquid for a given time and at a given temperature  
 
3 Types of radiator hoses  
 
3.1 The material for the lining and cover of the hose shall comply with the requirements given in Table 1.  
 
3.2 Dimensions and tolerances   
 
The dimensions and toleranc es shall comply with the requirements given in Table 2.  
 
Table 1 — Materials for radiator hoses  
 
SL No . Lining  Cover  
i) Resistant to ethylene glycol  Resistant to ethylene glycol  
ii) Resistant to ethylene glycol  Resistant to mineral oil  
iii) Resistant to  mineral oil  Resistant to mineral oil  
iv) Resistant to mineral oil  Resistant to ethylene glycol  
 
4 Construction  
 
4.1 Inner rubber lining  
 
4.1.1  For hoses below 50 mm in diameter, the inner rubber lining shall be seamless, uniform, free from air 
blisters,  porosity and other defects.  
 
4.1.2  For hoses above 50 mm in diameter, the lining shall be built up of two or more plies of rubber sheets.  
 
4.2 Reinforcement plies    
 
4.2.1  For hoses below 50 mm in diameter, the reinforcement plies shall be of knitted cons truction fabric.  
 
4.2.2  For hoses above 50 mm in diameter, the reinforcement plies shall be either of knitted fabric or 
braided yarn.  DKS 395:2020             
                              ©KEBS 2020 — All rights reserved  2  
4.2.3  The fabric or yarn shall be well fractioned or suitably spread on both sides with a rubber compound.  
 
4.2.4  For hos es with woven fabric reinforcement, the overlap of plies shall be not less than 12.5 mm if 
longitudinal, but if spiral the overlap shall be at least 10 % of the width.  
 
                      Table 2 — Internal and external diameters of radiator hoses  
 
           All dimensions in millimetres  
 
Internal diameter  
  
External diameter  
  
Tolerance on internal and 
external diameter  
 
 
10.0  
16.7  
 
12.5 20.0  
16.0 23.0 ± 0.75  
20.0 28.5  
22.0 32.0  
 
   
25.0 35.0  
28.0 38.0 ± 1.25  
31.5 41.0  
 
   
35.0 45.0  
38.0 48.0  
41.0 50.0  
45.0 56.0  
50.0 65.0 ± 1.50  
56.0 70.0  
63.0 77.0  
70.0 84.0  
75.0 90.0  
 
4.3 Cover   
 
The cover shall have a cloth marked finish or a smooth finish.  
 
5 Test requirements for finished hoses  
 
5.1 Duration pressure   
 
When tested by t he method described in Annex A, the hose test piece shall comply with the requirements 
given in Table 3.  
 
5.2 Adhesion   
 
When tested by the method described in Annex B, the adhesion between ‘lining and fabric or lining and 
braids, or cover and braids’, shall b e not less than 1.5 kN/m, both in the air for 12 h at 100 ºC.  
 
5.3 Resistance to vacuum collapse  
 
 When the finished hose is subjected to crushing under 0.03 MPa at 100 ºC for 10 min, the deformation shall 
not exceed 30 % of the external diameter.  
 
 
 
 
                              KS395: 2020  
©KEBS 2020 — All rights reserved          
     3 
 5.4 Resistance to liquids  
 
5.4.1  Resistance to ethylene glycol  
 
When tested by the method described in Annex C, the test liquid, being a mixture of 60 % ethylene glycol 
and 40 % water volume, temperature being maintained at 100 ºC ± 1 ºC, for 70 h ± 20 h, the percenta ge 
change in volume of the hose specimen shall not exceed 5 % of the initial volume.  
 
Table 3 — Bursting pressure test requirements for radiator hoses  
 
Internal diameter  
(mm)  Minimum bursting pressure  
(Mpa)  
 
10.0  
 
12.5                      2.50 
16.0  
20.0 
  
 
22.0  
 
25.0  
28.0  
31.5 1.50 
35.0  
38.0  
41.0  
  
45.0  
50.0  
56.0 0.75 
63.0  
70.0  
75.0  
 
The specimen shall also show no signs of separation of the lining and fabric or braided yarn on visual 
examination.  
 
5.4.2  Resistance to mineral o il  
 
When tested by the method described in Annex C, the test liquid, being mineral oil with a kinematic viscosity 
of 32 ± 1 centistoke at 37.8 ºC and a flash point of 165 ºC ± 3 ºC, test temperature being maintained at 100 
ºC ± 1 ºC, hose specimen shall n ot exceed 50 %.  
 
5.5 Low temperature test  — Compression set at low temperature   
 
When tested as described in Annex D, with the hose specimen at 25 ºC ± 1 ºC, and allowed to recover for 30 
min after the end of the exposure time, the compression set shall not ex ceed 75 %.  
 
6 Packaging and marking  
 
6.1  Packaging  
 
Hoses shall be so packaged or wrapped so as to prevent them from being  damaged during transportation 
and storage.  
 
 
 
 
 DKS 395:2020             
                              ©KEBS 2020 — All rights reserved  4  
6.2  Marking  
 
The following information shall appear in legible and indelible markin g on a label securely attached to each 
hose:  
 
a) the manufacturer’s  name and/or trade mark;  
 
 
 
b) the month and year of manufacture.  
c) Part number  
d) Country of origin  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
                              KS395: 2020  
©KEBS 2020 — All rights reserved          
     5 
  
Annex  A  
(normative)  
 
Bursting pressure test  
 
A.1 The free length of the hose test piece excluding end reinforcements or couplings shall be 1 m.  
 
A.2 Measure the external diameter at three places along the length, two observations being taken at 
each point at right angles to each other.  Average the res ults of six observations and record the value as the 
diameter of the hose.  Use a square caliper having a vernier scale and a locking device.  
 
Fill the test piece with water prior to application of hydrostatic pressure allowing all air in it to escape thro ugh 
a stopcock provided for this purpose, to eliminate risk of injury to the operator due to the sudden expansion 
of trapped air released when the hose bursts.  
 
 Close the stopcock and increase the hydrostatic pressure at a uniform rate of 0.075 MPa per se cond by 
means of a hand or power -driven hydraulic pump or an accumulator system.  The pressure shall be 
measured with a calibrated dial –gauge.  
 
When the specified test pressure is reached, maintain this pressure steadily, and measure the external 
diameter of the hose as done initially.  Record the average value as the diameter of the hose at that 
pressure.  
 
Increase the rate of application of the hydraulic pressure as specified in Table 3, the test shall be 
discontinued and the sample destroyed.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 DKS 395:2020             
                              ©KEBS 2020 — All rights reserved  6  
 
Annex B  
(normative)  
 
Adhesion strength test  
 
B.1 Cut two test pieces from the hose having a length of 25.0 mm ± 0.5 mm in planes perpendicular to 
the axis of the hose by mounting it on a smooth, close fitting slightly tapered wood en mandrel, which may be 
rotated in a lathe and cutting a 25 mm section with a sharp pointed knife.  
 
B.2 The test piece shall be conditioned immediately before testing, for a minimum of 24 h, in one of the 
standard atmospheres, either 20 ºC ± 2 ºC and 65 %  ± 5 % relative humidity or 23 ºC ± 2 ºC and 50 % ± 5 % 
relative humidity.  The conditions shall be selected so that the test is carried out at the same temperature 
and humidity as used in the conditioning procedure.  
 
B3. Fit a test piece tightly on a mand rel B with an outside diameter substantially equal to the internal diameter of 
the test piece.  Separate the ply to be tested sufficiently to permit the attachment of a clamp C.  Apply to the 
separated ply a load (the total load specified consisting of the  combined weights of the clamp C, light steel 
spring E, together with the scale pan F and weights W) with the mandrel supported horizontally on the freely 
rotatable shaft D.  
 
Determine the rate of separation by observing the duration of the test and measur ing the length stripped 
between the marks indicating the beginning and the end of the test after the load has been removed.  Adjust 
the loads to maintain a steady rate of separation of 25 mm per minute.   
 
The adhesion strength shall be expressed in newton s per metre width of the hose test piece.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
                              KS395: 2020  
©KEBS 2020 — All rights reserved          
     7 
 Annex   C  
(normative)  
 
Test for resistance to liquids  — Gravimetric method  
 
C.1 The apparatus shall be a stoppered glass bottle or a tube of such dimensions that the test pieces 
remain comp letely immersed in the test liquid and freely exposed at all surfaces without restraint.  
 
C.2 The test piece shall be 1.0 cm3 to 3.0 cm3 in volume and of a uniform thickness of 2.0 mm ± 0.2 mm.  
 
C.3 Three hose samples shall be tested.  Weigh each test piec e in air to the nearest milligram ( m1) and 
then reweigh each test piece in distilled water ( m2).  Place them suitably separated, in a glass container with 
a volume of the immersion liquid at least 15 times the combined volume of the test piece and sufficie nt to 
keep them totally immersed.  At the end of the immersion period, bring the test pieces to the standard 
laboratory temperature (20 ºC ± 2 ºC) by quickly transferring them to a fresh portion of the immersion liquid 
at this temperature for a period of n ot less than 180 s and not more than 3 600 s.  Remove the surplus 
immersion liquid from the surfaces of each test piece by blotting with filter paper.  Then immediately place 
the test piece in a tarred and stoppered weighing bottle and determine its mass i n air ( m3) to the nearest 
milligram.  Remove the test piece from the bottle and immediately weigh in distilled water ( m4) at the 
standard laboratory temperature.  
 
C.4 The swelling is given by the formula:    
 
 
100  x  
) () () (
2 12 1 4 3
m mm m m m
  
 
where  
 
 m1  =  initia l mass of the hose in air,  
 m2  =  initial apparent mass of the hose after immersion,  
 m3  =  mass in air of the hose after immersion, and  
 m4  =  apparent mass in water of hose after immersion.  
 
The average of values of three test pieces shall be recorded  as the swelling of the hose.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 DKS 395:2020             
                              ©KEBS 2020 — All rights reserved  8  
Annex  D  
(normative)  
 
Test for compression set at low temperatures  
 
D.1 The compression apparatus shall be pairs of parallel, flat and highly polished chromium -plated steel 
plates or highly polished sta inless steel plates with a finish not worse than 0.2 mm centre line average.  Their 
transverse dimensions shall be 750 mm x 50 mm and thickness shall be 10 mm.  
 
Mild steel spacers in form of rings shall be used to provide the specified compression.  The sp acers shall be 
of such size that contact with the compressed test pieces is avoided.  
 
D.2 A quick release device, such as a can -or air -operated vice or pliers, shall be provided for holding 
plates and test pieces under compression.  A suitable pair of tong s shall be provided.  
 
D.3 A cabinet in which the test pieces are exposed may be of the mechanically refrigerated type or may 
be cooled directly by dry ice or liquid nitrogen.  Temperature in the cabinet shall be controlled within ± 1 ºC of 
the specified te mperature, while the test temperature shall be measured directly on the plates of 
compression apparatus within ± 0.5 ºC.   
 
D.4 The test piece shall be either of diameter 29.0 mm ± 0.5 mm and thickness 12.5 mm ± 0.5 mm or 
diameter 13.0 mm ± 0.5 mm and thic kness 6.3 mm ± 0.3 mm.  
 
The thickness shall be measured by a micrometer dial gauge with two contact members having flat circular 
surfaces of 9.5 mm diameter.  
 
D.5 The test pieces shall be conditioned immediately before testing for a minimum period of 3 h a t a 
standard laboratory temperature.  The compression apparatus shall also be kept at the standard laboratory 
temperature and the operating surfaces carefully cleaned.