FINAL DRAFT UGANDA 
STANDARD  
  FDUS 898-2 
First Edition  
2011 -mm-dd 
 
 
 Reference number  
FDUS 898-2: 2011 
© UNB S 2011  
  
Types 1, 2 and 3 Polypropylene (PP) pipes  — Part 2: General 
quality requirements and testing  
 FDUS 898-2: 2011 
ii © UNBS 2011 – All rights reserved  
 Compliance with this standard does not, of itself confer immunity from legal obligations  
A Uganda Standard does not purport to include all necessary provisions of a contract. Users are 
responsible for its correct application  
© UNBS 20 10  
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilised in any 
form or by any means, electronic or mechanical, including photoc opying and microfilm, without prior written 
permission from UNBS.  
Requests for permission to reproduce this document should be addressed to  
The Executive Director  
Uganda National Bureau of Standards  
P.O. Box 6329  
Kampala  
Uganda  
Tel: 256 41 4 505 995  
Fax: 25 6 414 286 123  
E-mail: unbs@infocom.co.ug  
Web: www.unbs.go.ug  FDUS 898-2:2011 
© UNBS 2011 – All rights reserved  iii 
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ...................... iv 
1 Scope  ................................ ................................ ................................ ................................ ................ 1 
2 Normative references  ................................ ................................ ................................ ....................... 1 
3 Material  ................................ ................................ ................................ ................................ ............. 1 
4 Requirements  ................................ ................................ ................................ ................................ ...2 
4.1 Condition on delivery  ................................ ................................ ................................ ....................... 2 
4.2 Surface finish ................................ ................................ ................................ ................................ ....2 
4.3 Dimensions and limit deviations  ................................ ................................ ................................ .....2 
4.4 Creep strength  ................................ ................................ ................................ ................................ ..2 
4.5 Impact strength  ................................ ................................ ................................ ................................ 6 
4.6 Heat reversion  ................................ ................................ ................................ ................................ ..6 
5 Testing  ................................ ................................ ................................ ................................ .............. 6 
5.1 Surface finish ................................ ................................ ................................ ................................ ....6 
5.2 Dimensions  ................................ ................................ ................................ ................................ .......6 
5.3 Ovality  ................................ ................................ ................................ ................................ ............... 6 
5.4 Creep strength  ................................ ................................ ................................ ................................ ..6 
5.5 Impact strength  ................................ ................................ ................................ ................................ 7 
5.6 Heat reversion  ................................ ................................ ................................ ................................ ..9 
5.7 Certificate  ................................ ................................ ................................ ................................ ....... 10 
 FDUS 898-2: 2011 
iv © UNBS 2011 – All rights reserved  
 Foreword  
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministry of Tourism, Trade and 
Industry established under Cap 327 , of the Laws of Uganda.  UNBS is mandated to co -ordinate the 
elaboration of standards and is  
(a) a member of International Organisation for Standardisation (ISO) and  
(b) a contact point for the WHO/FAO Codex Alimentarius Commission on Food Standards, and  
(c) the National Enquiry Point on TBT/SPS Agreements of the World Trade Organisation (WTO).  
The work of preparing Uganda Standards  is carried out through Technical Committees. A Technical 
Committee is established to deliberate on standards in a given field or area and consists of representatives of 
consumers, traders, academicians, manufacturers, government and other stakeholders.  
Draft Uganda Standards adopted by the Technical Committee are widely circulated to stakeholders and the 
general public for comments. The committee reviews the comments before recommending the draft standards 
for approval and declaration as Uganda Standards b y the National Standards Council.  
Committee membership  
The following organisations were represented on the Technical Committee for Building and civil engineering 
standards during the development of this standard:  
 Department of Geological Mines and Surveys  
 Gentex Entreprises Ltd  
 Makerere University  
 Ministry of Works and Transport  
 Multiple Industries Ltd  
 Uganda Institution of Professional Engineers  
 Uganda National Bureau of Standards  
 Uganda National Association of Plumbers  
 FINAL DRAFT UGANDA STANDARD  FDUS 898-2: 2011 
 
© UNBS 2011 – All rights reserv ed 1 
 Types 1, 2 and 3 Polypropylene (PP ) pipes  — Part 2:General 
quality requirements and testing  
1 Scope  
This Final Draft Uganda S tandard specifies requirements and the relevant methods of test for seamless pipes 
of circular cross section made from propylene homo polymers (PP -H) (type 1), therm oplastic propylene impact 
copolymers (PP -B) (type 2) or thermoplastic propylene random copolymers (type 3). 
Individual requirements specified in this standard may be omitted or supplemented in technical delivery 
conditions relating to particular applicatio ns. 
2 Normative references  
The following referenced documents are indispensable for the application of this standard .  For dated 
references, only the edition cited applies. For undated references, the latest edition of the referenced 
document (including an y amendments) applies.  
DIN 323 -1, Preferred numbers and preferred number series — Basic, calculated and rounded values  
DIN 16774 -1, Plastic moulding materials — Polypropylene and propylene copolymer thermoplastics — 
Classification and designation  
DIN 16774 -2, Plastics moulding materials — Polypropylene (PP) moulding materials — Preparation of 
specimens and determination of their properties  
DIN 16887 , Determination of the long -term hydrostatic pressure resistance of thermoplastics pipes  
DIN 50011 -11, Artific ial climates in technical applications — Controlled -atmosphere test installations - General 
concepts and requirements  
DIN 51222 , Pendulum impact testing machines with an energy of 50 J or less — Requirements and 
verification  
DIN 53453 , Impact testing of pl astics by the torsion pendulum test  
DIN 53759 , Creep testing of plastics hollow bodies  
DIN EN 10204 , Inspection documents for metallic products (includes Amendment A 1 : 1995)  
FDUS 898 -1, Polypropylene (PP) pipes - Dimensions  
3 Material  
Pipes shall be mad e from polypropylene (PP) moulding material, stabilized by means of suitable antioxidants. 
The choice of stabilizers and other additives shall be left to the pipe manufacturer.  
Moulding material of unknown composition shall not be used.  FDUS 898-2: 2011 
2 © UNBS 2011 – All rights reserved  
 4 Requirements  
4.1 Condition on delivery  
Pipe ends shall be cut as square as possible to the pipe axis.  
Pipes shall be free from blisters, shrink holes and inhomogeneities which would impair their performance in 
service. They shall be of uniform colour throughout.  
4.2 Surfac e finish  
The internal and external pipe surfaces shall be smooth. Slight corrugations, with consequent variations in 
wall thickness, are acceptable provided that the thickness of the pipe wall is at no point less than that 
specified in FDUS 898 -1. Pipes wi th sharp -edged grooves or sink marks are not permitted.  
4.3 Dimensions and limit deviations  
The pipe outside diameter and wall thickness shall comply with the specifications of FDUS 898 -1, which also 
applies by analogy to pipes of sizes deviating from the series of preferred numbers given in DIN 323 -1 and 
from international specifications.  
4.4 Creep strength  
When tested in accordance with 5.3 using the test conditions specified in Table 1, pipes shall neither burst nor 
leak during the prescribed period of s tressing.  
The diagrams in figures 1 to 3 are based on tests carried out in accordance with DIN 16887 . Extrapolated 
sections of the curves (with pipes tested at 110  °C) are dashed.  
The hoop stresses*1 marked 0 in the diagrams correspond to the σ o values sp ecified in Table 1.  
Table 1 — 
Test 
temperature,  
in °C  Exposure 
medium  Proof 
stress,  σ o   
 
N/mm2 PP-H 
Period of  
Stressing  
(minimum  time 
to failure),  t, 
h Proof  
stress,  σ o   
N/mm2 PP-B 
Period of  
Stressing  
(minimum  time 
to failure),  t, 
h Proof  
stress,  σ o   
N/mm2 PP-R 
Period of  
Stressing  
(minimum  
time to  
failure ), t, 
in h 
20 Air or water  21 1 16 1 16 1 
95 Air or water  3.5 1000  2.6 1000  3.5 1000  
110 Air 1.9 8 760*) 1.4 8760*) 1.9 8760*) 
*) For quality control testing performed at the start of production a nd at any change of material or manufacturing method  
(valid only temporarily).  
 
                                                   
1 Also termed 'basic stresses' in technical literature  FDUS 898-2: 2011 
© UNBS 2011 – All rights reserved  3 
 
 
 
 
 
 FDUS 898-2: 2011 
4 © UNBS 2011 – All rights reserved  
 
 
 FDUS 898-2: 2011 
© UNBS 2011 – All rights reserved  5 
 
 FDUS 898-2: 2011 
6 © UNBS 2011 – All rights reserved  
 4.5 Impact strength  
When tested in accordance with 5.4, the total number of failures shall not exceed 10 % of the  specimens 
tested.  
4.6 Heat reversion  
When tested i n accordance with 5.5, the mean relative change in pipe length shall not exceed 2 %.  
5 Testing  
5.1 Surface finish  
The pipe internal and external surfaces shall be inspected using back lighting . 
5.2 Dimensions  
The mean pipe outside diameter shall be establi shed, to the nearest 0 .1 mm, by circumferential measurement 
at both ends of the pipe. The wall thicknesses shall be determined, to the nearest 0 .1 mm, by measurement at 
four points per end, these being spaced as evenly as possible around the circumference.  Measurements shall 
be carried out at (23 ± 2) º C. 
5.3 Ovality  
Ovality is the difference between the maximum and the minimum outside diameters at the same cross section . 
It shall be measured immediately after manufacture and shall be determined to the nea rest 0 .1 mm  
5.4 Creep strength  
See DIN 53759 for  general information on this test. For each stress given in Table 1, three sections of pipe 
shall be taken as specimens and be cut to the following lengths:  
 for d ≤ 250 mm: l 3 ≈ 3d + 2l 5 +  250 mm  
 for d> 250 mm: l 1 ≈ 1 000 mm + 2 1 5. 
 
 
 
 
 
 
 
Figure 4  — Specimen for long -term hydrostatic pressure test  
 FDUS 898-2: 2011 
© UNBS 2011 – All rights reserved  7 
 where , 
d is the pipe outside diameter, in m illimetres ; 
l1 is the specimen length, in m illimetres ; 
l2 is the test len gth, in m illimetres ; 
l3 is the length of pipe zone affected by the end sealing devices being clamped, in m illimetres : 
for d  ≤ 250 mm: l 3  = d, 
 for d > 250 mm: l 3 = 250 mm;  
l4 is the assessment length, in m illimetres  (= l 2 - 2 l3); 
l5 is the length, in m illimetres , required for fixing the end sealing devices.  
The wall thickness shall be measured at eight points over l 4 and the outside diameter at three points, to an 
accuracy of 0 .1 mm, and the minimum wall thickness, s min and mean outside diameter, d, determined.  
Sealing devices shall be fitted at both ends of the specimen, which shall remain free to move in the axial 
direction during the test. The pipe shall be filled with water at the test temperature specified in Table 1 
(maintained to within ± 5 K) thr ough an aperture in one of the sealing devices, then placed in a water bath 
heated to test temperature (maintained to within ± 1 K) and kept there for not less than one hour to reach 
thermal equilibrium. If the pipe is filled with water at a lower temperat ure, it shall be kept in the bath for 12 h to 
ensure thermal equilibrium.  
The pressure in the pipe, which is to remain in the bath throughout the test, shall then be steadily increased to 
reach the specified proof stress within one minute. This pressure sh all be maintained to within ± 2.5 % for the 
period of stressing specified in table 1.  
The proof pressure, p e, p, shall be calculated from equation (1):  
 p e ,P =                                  2 . S min σ o.                                                                     
                                                     d - in                                                                                                             (1)  
[R1]where  
d is the mean outside diameter over l4; 
smin is the mi nimum wall thickness over l 4; 
σ o is the proof stress as specified in table 1.  
It shall be established whether the pipe leaks or bursts during the specified period of stressing. Tests where 
the pipe fails within length l 3 during that period shall not be counted and shall be repeated.  
5.5 Impact strength  
In accordance with the specifications given in Table 2, specimens shall be prepared from the pipes either in 
the form of pipe sections or of bars taken along the pipe axis (cf. Figure 5). The latter shall be taken from 
sections of pipe i n lengths of (50 ±  1) mm or (120 ± 2) mm at points spaced as evenly as possible around the 
circumference. The specimen width specified in Table 2 corresponds to dimension b in Figure 5.  FDUS 898-2: 2011 
8 © UNBS 2011 – All rights reserved  
 The internal and external surfaces of the specimens shall not be machi ned if the wall thickness, s, does not 
exceed 10,5 mm. Otherwise, the external surfaces shall be machined until the specimen thickness is (10 ± 
0.5) mm. The machined surfaces shall then be smoothed lengthwise with fine emery paper (of grain size No. 
220 or  finer).  
Testing shall be carried out on ten specimens on the lines of DIN 53453, using a DIN 51222 -15 pendulum  
impact testing machine, with the impact applied either to the external surface or the machined face of the 
specimen. Testing shall be carried ou t at (23 ± 2) °C for PP -H pipes and at (0  ± 2) °C for PP -B and PP -R 
pipes.  
It shall be established whether the specimens fail. If more than one specimen fails in this test, the test shall be 
repeated on a further 20 specimens taken from the same pipe. In t his case, the total number of failures from 
the first and second tests shall be evaluated together.  
 
Figure 5  — Specimen for impact test  FDUS 898-2: 2011 
© UNBS 2011 – All rights reserved  9 
 Table 2  —  
Dimensions in mm  
Type of  specimen  Outside  
diameter, d,  
in mm  Pipe  wall 
thickness, S,  
mm Specimen  Distance between  
supports,  
mm 
+0.5 
0 length,  
mm width,  
mm height,  
mm 
1 < 25 s Pipe section (100 ± 2) mm long  70 
2 ≥ 25 ≤ 4,2  50 ± 1  6 ± 0 .2 AS 40 
3 > 25 > 4,2  120 ± 2  15 ± 0 .5 max.10 .5 70 
 
5.6 Heat reversion  
Either complete sections of pipe, each about  200 mm long, shall be used as specimens, or where the pipe 
diameter is 200  mm or more, three pieces of pipe about 200  mm long taken along the pipe axis and with an  
approximate arc length of 200 mm shall be cut from the sample pipe. In the latter case, th e pipe section shall 
be divided into pieces measuring approximately 200 mm square ( for example,  a 200 x 11 .4 mm section will be 
divided into three, and a 1 000 x 38 .5 mm section, into 15 pieces). The direction of the pipe axis shall be 
marked on the pieces . All pieces shall be tested.   
A mark shall be scribed on the external surface approximately 50 mm from each end of the pieces so 
obtained, in the axial direction of the pipe (for complete pipe sections, the mark shall be scribed around the
 whole circumfer ence). The distance between the two marks, lo (reference length), shall be approximately 
100 mm and shall be measured, at (23  ± 2) °C, to an accuracy of 0 .25 mm.  
To ensure that changes in length are not obstructed, the specimens shall be placed concave sid e up on a 
glass plate dusted with talcum.  
The glass plate with the specimens shall then be placed in an oven with forced air circulation as specified in 
DIN 50011 -1 that has been brought to test temperature. The specimen shall be kept in the oven at the  
temperatures and for the periods specified in Table 3.  
Table  3 
Type of pipe  Test temperature,  
°C Minimum period of stressing,  t, 
min 
PP-H 150 ± 2 120 ± 2 
PP-B 150 ± 2 120 ± 2 
PP-R 135 ± 2 120 ± 2 
 
After removal of the specimens from the oven, they shall be left as they are on the plate to cool in air down to 
test temperature. The minimum distance between the gauge marks, l min shall then be measured.  FDUS 898-2: 2011 
10 © UNBS 2011 – All rights reserved  
 The relative change in length, ε  , as a percentage, is to be calculated using equation (2):  
ε =                    lo  -  lmin        . 100 
                   lo                                                                                                            (2) 
 
[R2]where  
lo is the distance between the gauge marks before thermal treatment;  
lmin is the distance between the gauge marks after thermal treatment and cooling.  
The mean of the relative changes in length, ε, calculated from the above equation, shall be taken as the mean 
relative change in length, ε , for the pipe concerned . 
5.7 Certificate  
If so agreed, a type 2.2 inspection document as in DIN EN 10204 shall be iss ued, giving the results of the in 
production tests carried out by the manufacturer.  
Explanatory notes   
This standard is a basic standard and therefore does not cover the scope of testing, inspection, or 
requirements  relating to special applications.  
The c reep test requirements specified here are based on experiments, which have shown the extent to which 
alternating temperature tests carried out at elevated temperatures can reduce test times. The probable service 
life of the pipes and various safety factors  have also been given due consideration.  
The investigations undertaken have demonstrated that polypropylene pipes may reasonably be expected to 
have a service life of more than 100 years (hitherto a service life of 50 years has been assumed, based on the 
requirements of the water authorities and long -term experience).  
It should be noted that the dimensions specified in FDUS 898 -1 apply likewise to PP -H, PP -B and PP -R pipes, 
whereas the allowable working pressures differ (which is reflected by the different o values given in Table 1). 
Specifications with respect to the composition of the pipe material and the methods of manufacture have not 
been included in order not to impede technical innovation. The specification that moulding material of 
unknown composit ion should not be used is intended to prevent the use of unsuitable material, while allowing 
the manufacturer to derive technical and economic advantages to be gained from using of his own rework 
material. The following type of moulding material specified in DIN 16774 -1 is generally used for the 
manufacture of polypropylene (PP) pipes:  FDUS 898-2: 2011 
© UNBS 2011 – All rights reserved  11 
 
 
 
 FDUS 898-2: 2011 
© UNBS 2011 – All rights reserv ed 13 
 Certification marking  
Products that conform to Uganda standards may be marked with Uganda National Bureau of Standards 
(UNBS) Certification Mark shown in the figure belo w.  
The use of the UNBS Certification Mark is governed by the Standards Act, and the Regulations made 
thereunder. This mark can be used only by those licensed under the certification mark scheme operated by 
the Uganda National Bureau of Standards and in co njunction with the relevant Uganda Standard. The 
presence of this mark on a product or in relation to a product is an assurance that the goods comply with the 
requirements of that standard under a system of supervision, control and testing in accordance wi th the 
certification mark scheme of the Uganda National Bureau of Standards. UNBS marked products are 
continually checked by UNBS for conformity to that standard.  
Further particulars of the terms and conditions of licensing may be obtained from the Direct or, Uganda 
National Bureau of Standards.  
 
 FDUS 898-2: 2011   
 
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