KENYA STANDARD       DKS 2491: 2019  
ICS 75.100  
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Base oil  — Specification  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
                  KEBS 2 019            Second  Edition  2019  
 
No copying of this standard without KEBS permission except as permitted by copyright law  DKS 2491: 2019  
 
ii           © KEBS 20 19 — All rights reserve d
    
 
 
TECHNICAL COMMITTEE REPRESENTATION  
 
The following organizations were represented on the Technical Committee:  
 
Kenya Bureau of Standards — Secretariat  
 
 
REVISION OF KENYA STANDARDS  
 
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improvements to published standards, addressed to the Managing Director, Kenya Bureau of Standards, are 
welcome.  
 
 
 
 
 
 
 
 
 
 
©Kenya Bureau of Standards, 201 9 
 
Copyright. Users are reminded that by virtue of Section 25 of the Cop yright Act, Cap. 12 of 2001 of the Laws of Kenya, copyright subsists in 
all Kenya Standards and except as provided under Section 26 of this Act, no Kenya Standard produced by Kenya Bureau of Standa rds 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 2491: 2019  
ICS 75.100  
© KEBS 20 19 — All rights reserve d                    iii  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Base oil  — Specification  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
KENYA BUREAU OF STANDARDS (KEBS)  
 
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 DKS 2491: 2019  
 
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Foreword  
 
This Kenya Standard was prepared by the Technical Committee on Petroleum and Petroleum Products  under  
the gui dance of Standards Projects Committee , and it is in accordance with the procedures of the Kenya Bureau  
of Standards . 
 
Lubricating base oils are lubricant components that provide an oil layer between moving surfaces, and remove 
heat and wear particles while  keeping friction and wear at minimum. To fulfill these requirements, base oils shall 
possess certain lubricant properties. These properties are in turn dependent on the chemical composition and 
structures of the hydrocarbon molecules present in the base o il, which are controlled by the refining process and 
the degree of refining of the base stock.  
 
Lubricant base oils shall be free of PCB (polychlorinated biphenyl) compounds to be suitable for use in 
commerce. Historically, it has been demonstrated that PC Bs are not present in lubricant base oils manufactured 
from virgin crude petroleum sources.  
 
Lubricant base oils should be essentially free of volatile organic halides because capable refining and re -refining 
processes would effectively remove all traces o f these materials. The presence of volatile organic halides in 
lubricant base oils indicates contamination with chlorinated solvents.  
 
Lubricant base oils should be essentially free of metallic elements. Sources of metallic elements potentially 
present in lubricant base oils include crude oil, refining or processing aids, residual lubricant additives, and 
residual corrosion or wear metals not removed in the re -refining process.  
 
  
   KENYA  STANDARD         DKS 2491: 2019  
 
 
© KEBS 20 19 — All rights reserve d   1  
Base oil  — Specification  
 
1 Scope  
 
This Kenya Standard covers the specificat ions and methods of test for base  oils composed of hydrocarbons and 
intended for use in formulating products including automotive and industrial lubricants . 
 
NOTE   This standard applies only to hydrocarbon lubricant base oils. Base oils containing detectab le levels of esters, animal fats, 
vegetable oils, or other materials used as, or blended into, lubricants are not covered by this standard . 
 
2 Normative reference s 
 
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 
any amendments) applies.  
 
ASTM D 91 , Standard test method for precipitation number of lubricating oils 
 
ASTM D 92 , Standa rd test method for flash and fire points by Cleveland open cup tester.  
 
ASTM D 97 , Standard Test Method for pour point of petroleum products  
 
ASTM D 130 , Standard test method for corrosiveness to copper from petroleum products by copper strip test 
 
ASTM D 445, Standard test method for kinematic viscosity of transparent and opaque liquids (and calculation of 
dynamic viscosity)  
 
ASTM D 524 , Standard test method for rams botto m carbon residue of petroleum products  
 
ASTM D 664 , Standard test method for acid number of petroleum products by potentiometric titration  
 
ASTM D 974 , Standard test method for acid and base number by color-Indicator titration  
 
ASTM D1298 , Standard test method for density, relative density, or API Gravity of crude petroleum and liquid 
petroleum products by hydrometer method  
 
ASTM D1401 , Standard test method for water separability of petroleum oils and synthetic fluids 
 
ASTM D 1500 , Standard test method for ASTM color of petroleum products (ASTM color scale)  
 
ASTM D 1744 , Standard test method for determination of water in liquid petroleum products by Karl Fischer 
reagent  
 
ASTM D2007 , Standard test method for characteristic groups in rubber extender and proces sing oils and other 
petroleum -derived oils by the Clay -Gel absorption chromatographic method  
 
ASTM D 2270 , Standard Practice for Calculating Viscosity Index from Kinematic Viscosity at 40 and 100°C  
 
ASTM D 2622 , Standard test method for sulfur in petroleum  products by wavelength dispersive x -ray 
fluorescence spectrometry  
 
ASTM D 2887 , Standard test method for boiling range distribution o petroleum fractions by gas chromatography  
 DKS 2491: 20 19 
 
2          © KEBS 20 19 — All rights reserve d
   ASTM D 3120 , Standard test method for trace quantities of sulfur in light liqu id petroleum hydrocarbons by 
oxidative microcoulometry  
 
ASTM D 4052 , Standard test method for density, relative density, and api gravity of liquids by digital density 
meter  
 
ASTM D 4059, Standard test method for analysis of polychlorinated biphenyls in ins ulating liquids by gas 
chromatography  
 
ASTM D 4291, Standard test method for trace ethylene glycol in used engine oil  
 
ASTM D 4294, Standard test method for sulfur in petroleum and petroleum products by energy dispersive x -ray 
fluorescence spectrometry  
 
ASTM D 4629, Standard test method for trace nitrogen in liquid petroleum hydrocarbons by syringe/inlet 
oxidative combustion and chemiluminescence detection  
 
ASTM D 4739, Standard test method for base number determination by potentiometric hydrochloric acid t itration  
 
ASTM D 4927, Standard test methods for elemental analysis of lubricant and additive components — barium, 
calcium, phosphorus, sulfur, and zinc by wavelength -dispersive x -ray fluorescence spectroscopy  
 
ASTM D 4929, Standard test methods for deter mination of organic chloride content in crude oil  
 
ASTM D 4951 , Standard test method for determination of additive elements in lubricating oils by inductively 
coupled plasma atomic emission spectrometry  
 
ASTM D 5185,  Standard test method for determination o f additive elements, wear metals, and contaminants in 
used lubricating oils and determination of selected elements in base oils by inductively coupled plasma atomic 
emission spectrometry (ICP-AES)  
 
ASTM D 5480, Standard test method for engine oil volatilit y by gas chromatography  
 
ASTM D 7042, Standard test method for dynamic viscosity and density of liquids by stabinger viscometer (and 
the calculation of kinematic viscosity ) 
 
3 Definitions  
 
For the purpose of this standard, t he following definitions apply:  
 
3.1 
base oil  
a base stock or a blend of two or more base stocks used to produce finished lubricants, usually in combination 
with additives  
 
3.2 
base stock  
a hydrocarbon lubricant component, other than an additive, that is produced by a single manufacture r to the 
same specifications (independent of feed source or manufacturer’s location), and that is identified by a unique 
formula number or product identification number, or both  
 
 
 
 
 
 KS 2491: 201 9 
 
© KEBS 20 19 — All rights reserve d   3 4 Requirements  
 
4.1 Physical properties  
 
The base oil shall meet the physical  properties detailed in Table 1 . 
 
Table 1  — Physical properties  
 
SL 
No. Physical property  Requirement  Test method  
i) Appearance  Bright and clear  visual  
ii) Colour, max . 6 D1500  
iii) Density at 15 °C ,kg/L , min . To be reported  D1298, D4052  
iv) Flash poi nt, °C, min . 180 D92 
v) Kinematic viscosity at 40  °C and 100  
°C, mm2/s (cSt)  To be reported  D445, D7042  
vi) Viscosity index, min .  90 D2270  
vii) Pour points, °C, max . -6 D97 
 
4.2 Compositional properties  
 
The base oil shall meet the compositional prop erties detailed in Table 2 . 
 
Table 2  — Compositional properties  
 
Sl No. Property  Requirement  Test method  
i) Micro carbon residue, % , mass , max  
 0.8 M ax. D4530  
ii) Sulfur, wt % , max  1.8 M ax. D2622, D4294, D3120  
 
 
4.3 Chemical properties  
 
The base oil shall meet the chemica l properties detailed in table 3  below;  
 
Table 3 — Chemical properties  
 
SL. 
No. Property  Requirement  Test method  
i) Acid number, mg KOH/g , max  0.10 D974 D664  
ii) Base number, mg KOH/g , max 1.2 D4739  D2896  
iii) Total chlorine, mg/kg , max  50 D4929  
iv) Copper corrosion 3 h at 100°C , max  +1 D130  
v) Elemental analysis, mg/kg:  
Mg, Na, Ba, Cu, B, Pb, Mn, Ni, Si   
 D5185  
 DKS 2491: 20 19 
 
4          © KEBS 20 19 — All rights reserve d
   Al, As, Cd, Ca, Fe, P, Zn, Cr, Sn,  
 
Total of all above elements , mg/kg , max  
 
25 (Also, D4628,  
D4927, D4951  have 
limited applicability)  
 
vi) Glycol, mg/kg , max  5 D4291  
vii) PCB (polychlorinated biphenyl)  
content, mg/kg , max  2 D4059  
viii) Total volatile organic halogens, mg/kg , 
max 5 EPA 8120  
ix) Water, mg/kg , max  
 
 150 D1744, D6304  
x) Ash wt % , max  0.01 D 482  
 
5 Pack aging and marking  
 
5.1 Pack aging 
 
The condition of each container for the base oil shall be such as to have no detrimental effect on the quality of 
the product during normal transportation and storage.  Only containers of the same size filled with base  oil from 
the same batch , shall be package d together.  
 
5.2 Marking  
 
The following information shall be clearly marked on the container, or on a label affixed to the container:  
 
a) the name and address the manufacturer or supplier ; 
 
b) the description of the product ; 
 
c) batch number/identification ; 
 
d) quantity ; and  
 
e) date of manufacture and expiry