DRAFT UGANDA STANDARD  
  DUS  2159 -2 
First  Edition  
2019 -mm-dd 
 
 
 Reference number  
DUS 2159 -2: 2019 
© UNBS 2019   
  
Hydraulic fluid  — Performance Classifications  — Part 2: 
Specifications for categories  HH, HL, HM, HV and HG  
 DUS 2159 -2: 2019  
ii © UNBS 2019  – 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 necess ary provisions of a contract. Users are 
responsible for its correct application  
© UNBS 2019   
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, i ncluding photocopying 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 4 333 2 50/1/2/3  
Fax: +256 41 4 286 123  
E-mail: info@unbs.go.ug  
Web: www.unbs.go.ug  DUS 2159 -2:2019  
© UNBS yyyy  – All rights reserved  iii 
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ............................  iv 
1 Scope  ................................ ................................ ................................ ................................ ......................  1 
2 Normative references  ................................ ................................ ................................ ............................  1 
3 Terms and definitions  ................................ ................................ ................................ ...........................  2 
4 General classification  ................................ ................................ ................................ ...........................  2 
5 Requirements  ................................ ................................ ................................ ................................ .........  3 
5.1 General requirements  ................................ ................................ ................................ ...........................  3 
5.2 Specific requirements  ................................ ................................ ................................ ...........................  3 
6 Packaging  ................................ ................................ ................................ ................................ ...............  3 
7 Labelling  ................................ ................................ ................................ ................................ .................  3 
8 Sampling  ................................ ................................ ................................ ................................ ................  4 
Annex  A (normative)  Laboratory/bench test requirements  ................................ ................................ ..........  5 
A.1 Specifications for ca tegory hydraulics fluids  ................................ ................................ ....................  5 
Bibliography  ................................ ................................ ................................ ................................ ......................  15 
. DUS 2159 -2: 2019  
iv © UNBS 2019  – All rights reserved  
 Foreword  
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministry of Trade , Industry and 
Cooperat ives established under Cap 327 , of the Laws of Uganda , as amended .  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 Alimentariu s Commission on Food Standards, and  
(c) the National Enquiry Point on TBT  Agreement  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 o n standards in a given field or area and consists of key stakeholders 
including government, academia, consumer groups, private sector and other interested parties.  
Draft Uganda Standards adopted by the Technical Committee are widely circulated to stakehol ders and the 
general public for comments. The committee reviews the comments before recommending the draft standards 
for approval and declaration as Uganda Standards by the National Standards Council.  
The committee responsible for this document is Technica l Committee UNBS /TC 16, Petroleum , Subcommittee 
SC 1 Petroleum and Petrochemical  
DUS 2159  consists of the following parts, under the general title Hydraulic Lubricating Fluid — Performance 
Classifications :  
  Part 2 : General  
  Part 2 : Specifications for ca tegories HH, HL, HM, HV and HG  
  Part 3 : Specifications for hydraulic fluids in categories HFAE, HFAS, HFB, HFC, HFDR and HFDU  
  Part 4: Specifications for hydraulic fluids in categories HETG, HEPG, HEES and HEPR  DUS 2159 -2:2019  
© UNBS yyyy  – All rights reserved  v 
 DRAFT UGANDA STANDARD  DUS 2159 -2: 2019  
 
© UNBS 2019  – All rights reserved  1 
 Hydraulic fluid  — Performance Classificat ions — Part 2: 
Specifications for categories HH, HL, HM, HV and HG  
1 Scope   
This Draft Uganda Standard specifies performance requirements, sampling and test methods for new mineral 
oil hydraulic fluids of categories classified as HH, HL, HM, HV and HG, and  intended for hydraulic systems, 
particularly for hydrostatic hydraulic fluid power application.  
2 Normative references   
The following referenced documents 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.  
US ISO 2160:1998, Petroleum products — Corrosiveness to copper — Copper strip tes t 
US ISO 2592:2000, Determination of flash and fire points — Cleveland open cup method  
US ISO 2909:2002, Petroleum products — Calculation of viscosity index from kinematic viscosity  
US ISO 3016:1994, Petroleum products — Determination of pour point  
US ISO 3104:1994, Petroleum products — Transparent and opaque liquids — Determination of kinematic  
viscosity and calculation of dynamic viscosity  
DUS ISO 3105:1994, Glass capillary kinematic viscometers — Specifications and operating instructions  
US ISO 3170:2004 , Petroleum liquids — Manual sampling  
US ISO 3448:1992, Industrial liquid lubricants — ISO viscosity classification  
DUS ISO 4259:2006, Petroleum products — Determination and application of precision data in relation to 
methods  of test  
DUS ISO 4263 -1:2003, Petroleum and related products — Determination of the ageing behaviour of inhibited 
oilsand fluids — TOST test — Part 1: Procedure for mineral oils  
DUS ISO 4406:1999, Hydraulic fluid power — Fluids — Method for coding the level of contamination by solid  
particles  
DUS ISO 5598:2008, Fluid power systems and components — Vocabulary  
DUS ISO 6072:2002, Hydraulic fluid power — Compatibility between fluids and standard elastomeric materials  
US ISO 6247:1998, Petroleum products — Determination of foaming characteri stics of lubricating oils  DUS 2159 -2: 2019  
2 © UNBS 2019  – All rights reserved  
 US ISO 6296:2000, Petroleum products — Determination of water — Potentiometric Karl Fischer titration 
method  
DUS ISO 6614:1994, Petroleum products — Determination of water separability of petroleum oils and 
synthetic  fluids  
DUS 21 59-1; 2019 Hydraulic Lubricating Fluid — Performance Classifications: Part 2: General  
DUS ISO 7120:1987, Petroleum products and lubricants — Petroleum oils and other fluids — Determination of  
rust-preventing characteristics in the presence of water  
DUS ISO 9120:1997, Petroleum and related products — Determination of air -release properties of steam 
turbine  and other oils — Impinger method  
DUS ISO 12937:2000, Petroleum products — Determination of water — Coulometric Karl Fischer titration 
method  
DUS ISO 13357 -1:2002, Petroleum products — Determination of the filterability of lubricating oils — Part 1:  
Procedure for oils in the presence of water  
DUS ISO 13357 -2:2005, Petroleum products — Determination of the filterability of lubricating oils — Part 2:  
Procedure  for dry oils  
DUS ISO 14635 -1:2000, Gears — FZG test procedures — Part 1: FZG test method A/8,3/90 for relative 
scuffing  load-carrying capacity of oils  
DUS ISO 20763:2004, Petroleum and related products — Determination of anti -wear properties of hydraulic  
fluids — Vane pump method  
DUS ISO 20764:2003, Petroleum and related products — Preparation of a test portion of high -boiling liquids 
for the  determination of water content — Nitrogen purge method  
3 Terms and definitions   
For the purposes of this document, the following terms and definitions apply .  
3.1 
Hydrostatic  
the transfer of energy from pressure differences , not from the kinetic energy of the flow . 
ISO and IEC maintain terminological databases for use in standardization at the following addresses:  
— ISO Online browsing platform: available at http://www.iso.org/obp  
4 Viscosity  classification  
The viscosity of the hydraulic fluid shall be classified basing on the ISO viscosity classification, as per 
designations indicated in US ISO 3448.  DUS  2159 -2: 2019  
© UNBS  2019 – All rights reserved  3 
 5 Requirements  
5.1 General requirements  
The Hydraulic fluid shall consist of acceptable petroleum products, or of acceptable synthetically prepared 
products, or of a combination of these two types of products, compounded in all cases, with such functional 
additives, for ex ample, detergents, dispersants, oxidation inhibitors and corrosion inhibitors as are necessary 
to enable it to comply with the other requirements of this standard.  
The appearance of the delivered oils shall be clear, bright,  and free of any visible particu late matter, under 
normal visible light at ambient temperature.  
The precision (repeatability and reproducibility) of the test methods for this Draft Uganda Standard and the 
interpretation of the results shall be in accordance with ISO 4259 and shall be con sulted in instances of 
uncertainty or disputes.  
, The Hydraulic fluid shall remain clear and homogeneous, and shall show no evidence of separation of 
components and no evidence of colour change.  
The Hydraulic fluid shall be compatible with other fluids of the same viscosity grade that comply with the 
requirements of this standard.  
5.2 Performance categories  
Candidate Hydraulic fluid shall be formulated such that their performance requirements meet one of the 
performance categories HH, HL, HM, HV and HG as s pecified in part 1 of this standard  
NOTE : The consumer shall refer to the owner’s or operator’s manual for recommended category of to be used 
in a specific  hydraulic system . 
5.2 Specific  requirements  
In addition to meeting the requirements given in Clause 5.1 above, hydraulic fluid shall comply with specific 
requirements  provided hereafter in Annex A . 
6 Packaging  
The condition of the drums or smaller containers and the bulk tankers in to which the hydraulic fluid is filled, 
shall have no detrimental effect on  the quality of the hydraulic fluid during normal transportation and storage. 
Only containers of the same size filled with hydraulic fluid of the same batch identification shall be packed 
together in a carton. Prior to use, containers shall be firmly secur ed with a tamper -proof seal.  
7 Labelling  
Each container and each carton (if present) shall be legibly and indelibly marked with the following information 
in English language.  
a) product name and application;  
b) name and address of the manufacturer and registere d trade mark if any and/or distributor’s name;  
c) category of fluid according to ISO classification;  
d) ISO viscosity grade;  DUS 2159 -2: 2019  
4 © UNBS 2019  – All rights reserved  
 e) net content;  
f) origin of the product/Made in; and  
g) date of production and the batch number  
h) expiry date  
i) Caution and warnings  
8 Sampling  
Sampling of hydraulic fluid  shall be carried out in accordance with FDUS 173 3 or FDUS 1732  
 DUS  2159 -2: 2019  
© UNBS  2019 – All rights reserved  5 
 Annex  A 
(normative)  
 
Laboratory/bench test requirements  
A.1 Specifications for category hydraulics fluids  
Table 1 — Specifications for category HH mineral oil hydra ulics fluids  
characteristics   
units  requirements  Test method  
Viscosity grade (ISO 3448)  
 — 
 VG 10  VG 15  VG 22  VG 32  VG 46  VG 68  VG 100  VG 150  — 
Kinematic viscosity at 40 °C:  
 mm2/s a 
 9.00 – 
11.0 13.5 – 
16.5 19.8 – 
24.2 28.8 – 
35.2 41.4 – 
50.6 61.2 – 
74.8 90.0 – 
11.0 13.5 – 
16.5 ISO 3104 
and ISO 
3105  
Flash point:  
— Cleveland open cup, (min)  °C 125 140 165 175 185 195 205 215 ISO 2592  
Pour point, (max)  
 °C –15 –12 –9 –6 –6 –6 –6 –6 ISO 3016  
Acid number, (max)  
 mg KOH/g  0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 ISO 6618 or 
ISO 6619  
Water content, (max)  % (m/m)  0.025  0.025  0.025  0.025  0.025  0.025  0.025  0.025  ISO 6296 or 
ISO 12937  
a Square millimetres per second (mm2/s) is equivalent to centistokes (cSt)  DUS 2159 -2: 2019  
6 © UNBS 2019  – All rights reserved  
 Table 2 — Specifications for category HL mineral oil hydra ulics fluids  
characteristics   
units  requirements  Test 
method  
Viscosity grade (ISO 3448)  
 — 
 VG 10  VG 15  VG 22  VG 32  VG 46  VG 68  VG 100  VG 150  — 
Kinematic viscosity at:  
20 °C,  (max)  
 
0 °C, (max)  
 
40 °C   
100 °C,  (min)   
 
 
 
mm2/s a 
 600 
 150 
 300 
 
 420 
 780 
 1400  
 2560  
  4500  
 ISO 3104 
and 
ISO 3105  90 13.5 – 
16.5 19.8 – 
24.2 
 28,8 – 
35,2 
 41.4 – 
50.6 
 61.2 – 
74.8 
 90.0 – 
11.0 
 13.5 – 
16.5 
 
9.00 – 11.0 3.20 4.10 5.00 6.10 7.80 9.90 14.0 
2.50        
Flash point,(min)  °C 125 140 165 175 185 196 206 215 ISO 2592  
 
Pour point,  °C -30 -27 –21 –81 –15 –12 –12 –12 ISO 3016  
Water content,  % (m/m)  0.025  0.025  0.025  0.025  0.025  0.025  0.025  0.025  ISO 6296  
or 
ISO 12937 
or 
ISO 20764  
Water separation: b 
— time to 3 ml emulsion at 54 
°C, (max)  
time to 3 m l emulsion at 82 °C, 
(max)  min 30 30 30 30 30 30 - - ISO 6614  
min - - - - - - 30 30 
Copper corrosion, 100 °C, 3 h, 
(max)  class  2 2 2 2 2 2 2 2 ISO 2160  DUS  2159 -2: 2019  
© UNBS  2019 – All rights reserved  7 
 Rust prevention, 24 h:  
— Procedure A  
— Procedure B  
 — Pass  Pass  Pass  Pass  Pass  Pass  Pass  Pass  
 ISO 7120  
— - - - Pass  Pass  Pass  Pass  Pass  
Foam:  
— Sequence I, (max)  
— Sequence II, (max)  
— Sequence III, (max)  ml 150/0  
 
 150/0  
 
 150/0  
 
 150/0  
 
 150/0  
 
 150/0  
 
 150/0  
 
 150/0  
 
 ISO 6247  
 
ml 80/0 80/0 80/0 80/0 80/0 80/0 80/0 80/0 
ml 150/0  150/0 150/0  150/0  150/0  150/0  150/0  150/0  
Air release:  
— at 50 °C, (max)  min 5 5 5 5 5 10 10 - ISO 9120  
 
Elastomer compatibility c 
NBR 1, 100 °C, 168 h  
— relative increase in volume  
 % 
 0 to 18  
 0 to 15  0 to 15  0 to 12  0 to 12  0 to 10  0 to 10  0 to 10  ISO 6072  
— change in Shore A hardness  — 0 to -10 0 to -8 0 to -7 0 to -7 0 to -6 0 to -6 0 to -6 0 to -6 
Oxidation stability:  
— increase in acid number after 
1,000 h, (max)   2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 ISO 4263 -1 
a Square millimetres per second (mm2/s ) is equivalent to centistokes (cSt ) 
b This method is not required for fluids with detergent properties.  
c The definition of compatibility for types of elastomers other than NBR 1 (e.g. FPM, EPDM, AU) may be agreed between the suppl ier and the end -users.  
 
 
 
 DUS 2159 -2: 2019  
8 © UNBS 2019  – All rights reserved  
  
Table 3 — Specifications for category HM mineral oil hydraulics fluids  
 
characteristics   Oils of HL type with improved anti -wear and filterability properties a 
units  requirements  Test 
method  
Viscosity grade (ISO 3448)  
 — 
 VG 10  VG 15  VG 22  VG 32  VG 46 VG 68  VG 100  VG 150  — 
Kinematic viscosity at:  
20 °C, (max)  
 
0 °C, (max)  
 
40 °C   
 
100 °C  (min)   
 
 
 
mm2/s b  600 
  150 
  300  
 
 420 
 780 
 1400  
 2560  
  4500  
 ISO 3104 
and ISO 
3105  
90 13.5 – 
16.5 19.8 – 
24.2 
 28,8 – 
35,2 
 41.4 – 
50.6 
 61.2 – 
74.8 
 90.0 – 
11.0 
 13.5 – 
16.5 
 
9.00 – 11.0 3.20 4.10 5.00 6.10 7.80 9.90 14.0 
2,50        
Flash point:, (min)  °C 125 140 165 175 185 196 206 215 ISO 2592  
 
Pour point,  °C -30 -27 –21 –81 –15 –12 –12 –12 ISO 3016  
Water content,  % (m/m)  0.025  0.025  0.025 0.025  0.025  0.025  0.025  0.025  ISO 6296 or  
ISO 12937 
or 
ISO 20764  
Water separation: c 
— time to 3 ml emulsion at 54 
°C, (max)  min  30 30 30 30 30 30 30 30 ISO 6614  
— time to 3 ml emulsion at 82 
°C, (max)  min - - - - - - 30 30 DUS  2159 -2: 2019  
© UNBS  2019 – All rights reserved  9 
 Copper corrosion, 100 °C,  3 h, 
(max)  class  2 2 2 2 2 2 2 2 ISO 2160  
Rust prevention, 24 h:  
— Procedure A  
— Procedure B  
 — Pass  Pass  Pass  Pass  Pass  Pass  Pass  Pass  
 ISO 7120  
— - - - Pass  Pass  Pass  Pass  Pass  
Foam:  
— Sequence I, (max)  
— Sequence II, (max)  
— Sequence III, (max)  ml 150/0  
  
 150/0  
  
 150/0  
  
 150/0  
  
 150/0  
  
 150/0  
  
 150/0  
  
 150/0  
  
 ISO 6247  
 
ml 80/0 80/0 80/0 80/0 80/0 80/0 80/0 80/0 
ml 150/0  150/0  150/0  150/0  150/0  150/0  150/0  150/0  
Air release:  
— at 50 °C, (max)  min 5 5 5 5 10 13 - - ISO 9120  
 
Elastomer compatibility d 
NBR 1, 100 °C, 168 h  
— relative increase in volume  
— change in Shore A hardness  %  
 0 to 18  
 0 to 15  0 to 15  0 to 12  0 to 12  0 to 10  0 to 10  0 to 10  ISO 6072  
— 0 to -10 0 to -8 0 to -7 0 to -7 0 to -6 0 to -6 0 to -6 0 to -6 
Oxidation stability:  
— increase in acid number after 
1000 h, (max)   2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 ISO 4263 -1 
Wear protection, FZG A/8,3/90, 
(min)  Fail load 
stage  - - - 10 10 10 10 10 ISO 
14635 -1  
 
Wear protection, vane pump j 
— weight loss cam ring, (max)  
— weight loss vanes, (max)  mg mg  - - - 120 120 120 - - ISO 20763, 
procedure A  
 - - - 30 30 30 - -  
Filterability, dry  
— Stage I filterability, (min) e % 80 80 80 80 80 80 80 80 ISO 13357 -2 
— Stage II filterability, (min) f % 60 60 60 60 60 60 60 60 DUS 2159 -2: 2019  
10 © UNBS 2019  – All rights reserved  
 Filterability, wet  
— Stage I filterability, (min) e 
 % 50 50 50 50 50 50 50 50 ISO 
13357 -1  
 
— Stage II filterability, (min) f % 50 50 50 50 50 50 50 50 
a typical application is for general hydraulics.  
b Square millimetres per second (mm 2/s) is equivalent to centistokes (cSt). c Report.  
c This method is not required for fluids with detergent properties.  
d The definition of compatibility for types of elastomers other than NBR 1 (e.g. FPM, EPDM, AU) may be agreed between the suppl ier and th e end -users.  
e The stage I determination is based upon a comparison of the mean flow rate of a fluid through a test membrane with its initia l flow rate. Oils having good stage I filterability, but only a poor stage II 
performance (see footnote l), are unli kely to give performance problems in use, unless extremely fine system filters are utilized.  
f The stage II determination is based upon the ratio between the initial flow rate of fluid through the test membrane and the r ate at the end of the test. It is co nsidered that this part of the procedure is a more 
severe test,and is more sensitive to the presence of gels and fine silts in the oil. Silts and gels can be present in an oil when it is produced, or can be formed as an oil ages, especially when hot. An oi l with 
good  stage II filterability is unlikely to give filtration problems even in the most extreme conditions, and with fine (less than 5 μm) filtration present. Thus, it is suitable for use in more critical hydraulic and 
lubrication systems.  
 
Table 4 — Specificati ons for category HV mineral oil hydraulics fluids  
characteristics  Oils of HM type with improved viscosity/temperature properties a 
units  requirements  Test method  
Viscosity grade (ISO 3448)  
 — 
 VG 10  VG 15  VG 22  VG 32  VG 46  VG 68  VG 100  VG 150  — 
Kinemat ic viscosity at:  40 °C   mm2/s b  90 - 11 13.5 – 16.5 19.8 – 24.2  
 28.8 – 
35.2 
 41.4 – 
50.6 
 61.2 – 
74.8 
 90.0 – 
110 
 135 – 
165 
 ISO 3104 
and ISO 
3105  
Viscosity index  - 140 140 140 140 140 140 140 120 ISO 2909  
 
Flash point:, (min)  °C 125 125 175 175 180 180 180 200 ISO 2592  
 
Pour point,  °C -39 -39 –39 –30 –27 –24 –21 –18 ISO 3016  DUS  2159 -2: 2019  
© UNBS  2019 – All rights reserved  11 
 Water content,  % 
(m/m)  0.025  0.025  0.025  0.025  0.025  0.025  0.025  0.025  ISO 6296 or 
ISO 12937 
or ISO 
20764  
Water separation: c 
— time to 3 ml emulsion at 54 
°C, (max)  
 
— time to 3 ml emulsion at 82 
°C, (max)   
 
min  
 30 30 30 30 30 30 30 30 ISO 6614  
- - - - - - 30 30 
Copper corrosion, 100 °C, 3 h, 
(max)  class  2 2 2 2 2 2 2 2 ISO 2160  
Rust prevention, 24 h:  
— Procedure A  
— Procedure B  — Pass  Pass  Pass  Pass  Pass  Pass  Pass  Pass  ISO 7120  
— b b b Pass  Pass  Pass  Pass  Pass  
Foam:  
— Sequence I, (max)  
— Sequence II, (max)  
— Sequence III, (max)   
ml 150/0  
  
 150/0  
  
 150/0  
  
 150/0  
  
 150/0  
  
 150/0  
  
 150/0  
  
 150/0  
  
 ISO 6247  
 
80/0  80/0  80/0  80/0  80/0  80/0  80/0  80/0  
150/0  150/0  150/0  150/0  150/0  150/0  150/0  150/0  
Air release:  
— at 50 °C, (max)  min 5 5 5 5 13 13 - - ISO 9120  
 
Elastomer compatibility d 
NBR 1, 100 °C, 168 h  
— relative increase in volume  
— change in Shore A hardness  %  
 0 to 18  
 0 to 15  0 to 15  0 to 12  0 to 12  0 to 10  0 to 10  0 to 10  ISO 6072  
— 0 to -10 0 to -8 0 to -7 0 to -7 0 to -6 0 to -6 0 to -6 0 to -6 
Oxidation stability:  
— increase in acid number after 
1 000 h, (max)   2.0 2.0 2.0 2.0 2.0 2.0 2.0  ISO 4263 -1 
Wear protection, FZG A/8,3/90, Fail - - - 10 10 10 10 10 ISO DUS 2159 -2: 2019  
12 © UNBS 2019  – All rights reserved  
 (min)  load 
stage  14635 -1  
 
Wear protection, vane pump — 
weight loss cam ring, (max)  
 mg  - - - 120 120 120 - - ISO 20763, 
procedure A  
— weight loss vanes, (max)  mg - - - 30 30 30 - - 
Filter ability, dry  
— Stage I filterability, (min) e 
— Stage II filterability, (min)  g % 80 80 80 80 80 80 80 80 ISO 13357 -2 
60 60 60 60 60 60 60 60 
Filterability, wet  
— Stage I filterability, (min)  e 
— Stage II filterability, (min)  g % 50 50 50 50 50 50 50 50 ISO 
13357 -1  
 % 50 50 50 50 50 50 50 50 
a typical application is in mobile construction and marine equipment.  
b Square millimetres per second (mm2/s) is equivalent to centistokes (cSt).  
c This method is not required for fluids with detergent pr operties.  
d The definition of compatibility for types of elastomers other than NBR 1 (e.g. FPM, EPDM, AU) may be agreed between the suppl ier and the end users.  
e The stage I determination is based upon a comparison of the mean flow rate of a fluid throug h a test membrane with its initial flow rate. Oils having good stage I filterability, but only a poor stage II 
performance (see footnote l), are unlikely to give performance problems in use, unless extremely fine system filters are util ized.  
g The stage I I determination is based upon the ratio between the initial flow rate of fluid through the test membrane and the rate at the end of the test. It is considered that this part of the procedure is a more 
severe test, and is more sensitive to the presence of g els and fine silts in the oil. Silts and gels can be present in an oil when it is produced, or can be formed as an oil ages, especially when hot. An oil with 
good stage II filterability is unlikely to give filtration problems even in the most extreme condi tions, and with fine (less than 5 μm) filtration present. Thus, it is suitable for use in more critical hydraulic and 
lubrication systems.  
 
 
 
 
 
 DUS  2159 -2: 2019  
© UNBS  2019 – All rights reserved  13 
  
Table 5 — Specifications for category HG mineral oil hydraulic fluids  
 
Characteristics  Oils of HM type with  improved anti -stick -slip properties a 
Units  Requirements  Test method  
Viscosity grade (ISO 3448)  — VG 32  VG 68  — 
Kinematic viscosity  
— at: 0 °C(max)  
— 40 °C  
— 100 °C, (min)  mm2/s b 
 
 420 1 400  ISO 3104 and ISO 3105  
28,8 – 35,2 61,2 – 74,8 
5,00 7,80 
Flash point:, (min)   °C 175 95 ISO 2592  
Pour point, (max)   °C –18 –12 ISO 3016  
Water content, (max)   % (m/m) 0.025  0.025  ISO 6296 or ISO 12937  
or ISO 20764  
Copper corrosion, 100 °C, 3 h, (max)   class  2 2 ISO 2160  
Rust prevention, 24 h:  
— Procedu re A 
 
— Procedure B   
— 
 Pass  pass   
ISO 7120  
Pass  Pass  
Foam:  
— Sequence I, (max)  
— Sequence II, (max)  
— Sequence III, (max)   
 
ml 150/0  150/0   
 
ISO 6247  80/0 80/0 
150/0  150/0  
Elastomer compatibility c 
NBR 1, 100 °C, 168 h    
%  
  
  
 DUS 2159 -2: 2019  
14 © UNBS 2019  – All rights reserved  
 — relative increase in  volume  
— change in Shore A hardness   0 to 12  0 to 10  ISO 6072  
— 0 to -7 0 to -6 
Oxidation stability:  
increase in acid number after 1000 h, maximum   
—  
2.0  
2.0 ISO 4263 -1 
Wear protection, FZG A/8,3/90, (min)   Fail load stage  10 10 ISO 1463 5-1 
Wear protection, vane pump  
— weight loss cam ring, (max)  
— weight loss vanes, (max)   
  
mg 
  
120  
120  
ISO 20763  
Procedure A  30 30 
a A typical application is for machines with combined hydraulic and plain bearing way lubrication system where it is necessary to min imize vibration or intermittent sliding (slip -stick) at low 
speed.  
b Square millimetres per second (mm2/s) is equivalent to centistokes (cSt).  
c The definition of compatibility for types of elastomers other than NBR 1 (e.g. FPM, EPDM, AU ) may be agreed between the supplier and the end  users.  
 DUS  2159 -2: 2019  
© UNBS  2019 – All rights reserved  15 
 Bibliography  
[1] ISO 26422, Petroleum and related products — Determination of shear stability of lubricating oils 
containing polymers — Method using a tapered roller bearing  
[2] BS 2000 -281, Method s of test for petroleum and its products. Determination of anti -wear properties of 
hydraulic fluids. Vane pump method  
[2] IP 281, Determination of Anti -Wear Properties of Hydraulic Fluids — Vane Pump Method  
[2] DIN 51389 (all parts), Determination of lubri cants — Mechanical testing of hydraulic fluids in the vane -
cell-pump  
 DUS  2159 -2: 2019  
© UNBS  2019 – All rights reserved  17 
 Certification marking  
Products that conform to Uganda standards may be marked with Uganda National Bureau of Standards 
(UNBS) Certification Mark shown in the figure below.  
The use of t he 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 conjunction with t he 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 with the 
certifica tion 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 Director, Uganda 
Natio nal Bureau of Standards.  
 
 DUS 2159 -2: 2019    
 
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© UNBS 2019 – All rights reserved