ICS 71.100.70  
Reference number  
DRS 278: 2021  
© RSB 2021  
  
 RWANDA 
STANDARD  DRS  
278  
 
Second edition  
2021 -mm-dd 
 
Cosmetics — Methods of sampling  
   
DRS 278: 2021  
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    ©RSB2021  - All rights reserved  
 In order to match with technological development and to keep continuous progress in industries, 
standards are subject to periodic review. Users shall ascertain that they are in possession of the latest 
edition  
 
 
 
 
 
 
 
 
© RSB 2021  
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized 
in any form or by any means, electronic or mechanical, including photocopying and microfilm, without 
prior written permission from R SB. 
Requests for permission to reproduce this document should be a ddressed to : 
Rwanda Standards  Board  
P.O Box 7099 Kigali -Rwanda  
KK 15 Rd, 49  
Tel. +250 788303492  
Toll Free: 3250  
E-mail: info@rsb.gov.rw  
Website: www.rsb.gov.rw  
ePortal: www.portal.rsb.gov.rw  DRS 278: 2021  
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 Contents  
1 Scope  ................................ ................................ ................................ ................................ ......................  1 
2 Normative references  ................................ ................................ ................................ ............................  1 
3 Terms and definitions  ................................ ................................ ................................ ...........................  1 
4 Classification  ................................ ................................ ................................ ................................ .........  2 
5 Sampling requirements ................................ ................................ ................................ .........................  3 
6 Sampling during manufacturing  ................................ ................................ ................................ ..........  3 
6.1 General  ................................ ................................ ................................ ................................ ...................  3 
6.2 Batch  ................................ ................................ ................................ ................................ .......................  3 
6.3 Scale of sampling  ................................ ................................ ................................ ................................ .. 4 
6.4 Sampling instruments  ................................ ................................ ................................ ...........................  5 
6.5 Preparation of samples  ................................ ................................ ................................ .........................  5 
7 Sampling of packages ................................ ................................ ................................ ...........................  5 
7.1 General  ................................ ................................ ................................ ................................ ...................  5 
7.2 Gross sample  ................................ ................................ ................................ ................................ .........  6 
7.2.1  Samples for powders  ................................ ................................ ................................ ............................  6 
7.2.2  Sample for sticks and cakes  ................................ ................................ ................................ ................  6 
7.2.3  Samples for thick emulsions, pastes and gels  ................................ ................................ ..................  6 
7.2.4  Sample for homogeneous liquids and thin emulsions  ................................ ................................ ...... 7 
7.3 Test samples and reference samples  ................................ ................................ ................................ .. 7 
7.3.1  General  ................................ ................................ ................................ ................................ ...................  7 
7.3.2  Composite sample  ................................ ................................ ................................ ................................ . 7 
7.3.3  Indivi dual samples  ................................ ................................ ................................ ................................  7 
7.3.4  Reference sample  ................................ ................................ ................................ ................................ .. 7 
7.4 Number of tests  ................................ ................................ ................................ ................................ ..... 7 
7.5 Criteria for conformity ................................ ................................ ................................ ...........................  8 
Annex  A (normative)  Illustration of instrumentation units  ................................ ................................ ...........  9 
 DRS 278: 2021  
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 Foreword  
Rwanda Standard s are prepared by Technical Committees and approved by Rwanda Standards Board (RSB) 
Board of Directors in  accordance with the procedures of RSB,  in compliance with Annex 3 of the WTO/TBT 
agreement on the preparation, adoption and application of standards.  
The main task of technical committees is to prepare national standards. Final Draft Rwanda Standards 
adopted by Technical committees are ratified  by members of RSB Board of Directors for publication and 
gazettment as Rwanda Standards.  
DRS  278 was prepared by Technical Committee RSB/TC 011, Cosmetics and related products.  
In the preparation of this standard, reference was made to the following standard (s):  
1) KS 1668, Methods of sampling cosmetics  
The assistance de rived from the above source is hereby acknowledged with thanks.  
This second edition cancels and replaces the first edition (RS  278: 2015) which has  been technically revised.  
The following organizations were represented on the Technical Committee on Cosmetics and related products  
(RSB/TC 011) in the preparation of this standard.  
Paragraph of participants  
HORIZON - SOPYRWA Ltd  
University of Rwanda / College of Sciences and Technology (UR/CST)  
Rwanda Inspectorate, Competition and Consumer protection Authority (RICA)  
Rwanda Food and Drugs Authority  (RFDA)  
Rwanda Forensic Laboratory (RFL)  
Rwanda Medical Supply Ltd ( RMS)  
UBURANGA PRODUCTS LTD  
ORIBIT Company Ltd  
SULFO Rwanda Industries Ltd  
Beauty Makers Association (BMA)  DRS 278: 2021  
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 KANHAN Cosmetics Ltd  
Rwanda Investigation Bureau  (RIB)  
Rwanda Standards Board (RS B) – Secretariat  
 
 DRS 278: 2021  
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    ©RSB2021  - All rights reserved  
 Cosmetics  — Methods of sampling  
1 Scope  
This Draft Rwanda Standard describes methods of sampling cosmetics.  
2 Normative references  
The following documents are 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.  
RS EAS 786, Skin care creams, lotions and gels — Specification  
RS EAS 377 -3, Cosmetics and cosmetic products — Part 3: List of colorants allowed in cosmetic products  
3 Terms and d efinitions  
For the purposes of this working draft, the following terms and definitions apply.  
3.1 
acceptable quality level (AQL)  
 
designated value of per cent defective items that is accepted most of the time (approximately 95 times out of 100) 
by operatio n of the sampling plan  
3.2 
composite  sample  
sample prepared by mixing equal quantities of material from each of the gross samples in a lot and intendedto fully 
represent the lot as a whole  
3.3 
cosmetics  
 
any article intended to be rubbed, poured, sprinkled  or sprayed on, or introduced into, or otherwise applied to the 
human body or any part thereof for cleansing, beautifying, promoting attractiveness, or altering the appearance, and 
includes any article intended for use as a component of cosmetics  
 
3.4 
gros s sample  
 
sample prepared by mixing the part or whole of the material from some or all of the units in a package and intended 
to fully represent the package  DRS 278: 2021  
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 3.5 
individual sample  
sample obtained from a gross sample representing a package and intended for d etermining the specified 
characteristics of the material in the package  
3.6  
sample  
 
portion of a material selected in such a way that it represents all the characteristics of the material from which it is 
taken  
3.7 
sampling procedure  
 
succession of steps set out in this standard to ensure that the sample possess the essential characteristics of the 
bulk 
3.8 
test sample  
 
smaller sample prepared in a specified manner by subdivision of the gross sample. It has the essential 
characteristics of the gross sample  
 
3.9 
 
qualified person  
 
 
4 Classification  
For purposes of this standard, cosmetics shall be classified under three main groups namely solids, semi -solids and 
liquids. They shall be further subdivided as indicated in Table 1.  
 
Table 1— Classification of cosmetics  
Main group  Sub-group  Typical examples  
Solids  
 
 Powders  Skin powders, face powders and tooth powders  
Sticks or cakes  Compressed make -up, hair dyes, lipsticks and 
salves, and solid dentifrices  
Semi -solids  thick emulsions  Depilatories, shaving creams and tooth pastes  
Pastes (solid/liquid 
dispersions)  liquid make -ups, shaving creams and tooth pastes  DRS 278: 2021  
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 Liquids  Homogeneous liquids  After -shave lotions, eye lotions, hair oils and tonics, 
liquid brilliantines, nail polishes and varnishes, 
shampoos and perfumes  
thin emulsions  Face and hand lotions, hair darkeners and dressing 
and bindi  
 
5 Sampling requirements  
In drawing, preparing, storing and handling samples, the following precautions and directions shall be observed:  
 
a) samples shall be taken in a  protected place not exposed to damp air, dust or soot;  
b) the sampling instrument shall be clean and dry;  
c)  the samples, the material being sampled, the sampling instrument and the containers for samples shall 
be protected from adventitious contamination;  
d) the samples shall be placed in clean and dry glass containers;  
e) the sample containers shall be of a size such that they are almost completely filled by the sample;  
f)  each container shall be sealed air -tight after filling and marked with full details of sampling, batch or 
codenumber, name of manufacturer, and other important particulars of the consignment;  
g) the samples shall be stored in such a manner that the temperatu re of the material does not vary unduly 
from the normal temperature and they are protected from light; and  
h) sampling shall be done by a qualified person, and in the presence of the manufacturer or importer, or 
their representatives.  
6 Sampling during manufact uring  
6.1 General  
The sampling procedure at the point of manufacturing shall consist essentially of drawing samples of the finished 
product from the top, middle and bottom portions, of the process vessel immediately prior to packaging.  
6.2 Batch  
The material in a single mass obtained from the same raw materials and process of manufacture prior to packing 
shall be regarded as one batch. For instance, the material in a process vessel just before packaging shall be taken 
as constituting a batch.  DRS 278: 2021  
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 6.3 Scale of sampling  
In case of solid units such as sticks and cakes, at least three units shall be selected at random (see 6.3.1). In  
case of non -solid, at least three samples shall be drawn using appropriate sampling instruments (see 6.4), 
preferably taking the same number of sa mples from the top, middle and bottom portions of the batch.  
 DRS 278: 2021  
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 6.4 Sampling instruments  
6.4.1  For powders —Drawing samples of powders, a sampling tube, commonly known as a ‘thief’ shall be 
used (see Figure1). This usually consists of two closely fitting, concentric tu bes with matching slots that are 
closed by rotating the tubes with respect to each other. The ‘thief’ with the slots closed is inserted to the 
desired depth in a given process vessel. The slots are then opened, and the material flows through the open 
slots to fill the tube. The slots are then closed and the ‘thief’ is withdrawn.  
6.4.2  For Thick Emulsion Pastes and Gels  — Drawing samples of thick emulsion products, a sampling 
instrument similar to that described under 6.4.1 may be used. However, the top end of the  sampling tube should 
be connected to a suction device.  
6.4.3  For Homogeneous Liquids and Thin Emulsions  — Drawing samples of these products, a simple 
device (see Figure 2) may be used, consisting of a small bottle and two -hole stopper, one hole being fitted with a 
short glass tube and the other with a glass tube slightly longer than the depth of the vessel. To the longer tube is 
attached a stop -cock which is kept closed while the bottle is lowered to the desired depth in a given process vessel. 
The stop -cock is then opened and, as the air escapes through the longer tube, the product enters the bottle and fills 
it. An alternative sampling device (see Figure 3) consists of a tube fitted with a stopper at the lower end which can 
be closed by means of an attached rod that extends above the upper end of the tube. With the stopper disengaged, 
the tube is lowered slowly into the vessel so that the liquid enters it with minimum disturbance. When the bottom of 
the vessel has been reached, the lower end of the tube is cl osed with the stopper and the tube is removed . 
6.5 Preparation of samples  
6.5.1  Material of all the samples drawn from the batch according to 5.3 shall be disintegrated, if necessary , 
and mixed thoroughly to give the composite sample at the point of manufacture. The  material so chosen shall be in 
a quantity about 3 times the material required for carrying out a complete series of tests for all the requirements of 
the specification . 
6.5.2  The composite sample obtained in 6 .5.1 shall be examined for all the requirements of t he specification. 
The material in the batch shall be passed on for packing if the composite sample satisfies all the requirements . 
7 Sampling of packages  
7.1 General  
7.1.1  Sampling procedure for packages shall consist essentially in selecting and drawing a sufficient number 
of unit packs.  
7.1.2  Single consignment, all the packages containing cosmetics of the same type and form, representing 
the same batch of manufacture, shall constitute a lot. If the consignment consists of packages containing 
cosmetics of different types o r forms or batches of manufacture, then the packages containing products of the same 
type, form and batch of manufacture shall be grouped together; each group shall constitute a separate lot.  
7.1.3  For ascertaining the conformity of a lot to the requirements pre scribed in the specifications for 
individual cosmetics and toilet goods, tests shall be carried out on each lot separately. The number (n) of packages 
to be selected for drawing the samples shall depend on the size (N) of the lot in accordance with Table 2 . 
Table 2 — Scale of sampling for packages  DRS 278: 2021  
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 Number of packages in the lot  
(N) Number of packages to be selected  
(n) 
N ≤ 3 
3 <N ≤ 50 
50 <N ≤ 150 
150 <N ≤ 300 
300 <N ≤ 500 
N >500 Each container  
3 
4 
5 
6 
7 
 
7.1.4  The packages shall be selected at random and to ensure randomness of selection, random 
number tables shall be used. In case such tables are not available, the following procedure may be adopted:  
a)  starting from any package, count all the packages in one order as 1,2,3,…up to r and so on, where r is 
theintegral part of (N/n); and  
b) every r thpackage thus counted shall be withdrawn to give a sample for purposes of test.  
7.2 Gross sample  
7.2.1  Samples for powders  
Each of the packages selected as in 6.3, draw one or more containers at random. The material in the contai ners  so 
chosen from the package shall be about three times the quantity required for carrying out a complete series of tests 
for all the requirements of the specification. It shall be disintegrated, if necessary, and mixed thoroughly to give a 
gross sampl e. 
 
7.2.2  Sample for sticks and cakes  
Each of the packages selected as in 6.3, draw at random one or more sticks or cakes. The material so chosen from 
each package shall be about three times the quantity required for carrying out a complete series of tests for all the 
requirements of the specification. It shall be disintegrated in a suitable chopper and, after discarding the first and 
last chippings, the material shall be mixed thoroughly to give a gross sample.  
 
7.2.3  Samples for thick emulsions, pastes and gels  
Each  of the packages selected as in 6.3, draw at random a suitable number of containers and with the help of a 
suitable sampling implement, withdraw the material for the preparation of a gross sample. A simple device for 
withdrawing semi -solid products from ja rs consists of a glass tube about 1 cm in diameter and fitted with a piston. 
The piston is pulled out and the tube pressed in the semi -solid product; the tube is then withdrawn and the sample 
ejected out of it with the help of the piston. The material so d rawn from each package shall be about three times the 
quantity required for carrying out a complete series of tests for all the requirements of the specification. It shall be 
mixed thoroughly to give a gross sample.  
 
Note  In the case of emulsions and paste s, great care is necessary to ensure that there is no breakdown of the 
product.  DRS 278: 2021  
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 7.2.4  Sample for homogeneous liquids and thin emulsions  
Each of the packages selected as in 6.3, draw at random a suitable number of containers, shake them thoroughly to 
ensure homog eneity of the contents and draw samples with the aid of a suitable instrument. The material so drawn 
from each package shall be about three times the quantity required for carrying out a complete series of tests for all 
the requirements of the specificatio n. It shall be mixed thoroughly to give a gross sample.  
 
NOTE  In the case of liquid preparations containing alcohol or other volatile ingredients, great care is necessary to ensure that 
there is no loss on evaporation with resulting change in product make -up. 
7.3 Test samples and reference samples  
7.3.1  General  
All the composite and individual samples shall be transferred to separate containers. These containers shall then be 
sealed air -tight with stoppers, and labelled with full particulars of identification.  
 
7.3.2  Compo site sample  
Carefully segregate the gross samples obtained from a lot according to 6.1 from each of the gross samplesdrawn 
from the same lot, take a small but equal portion of material. Mix all these small portions thoroughly into a single 
composite mass, which should be of a size sufficient to carry out triplicate testing for all the characteristics specified 
under 6.2.2. This composite mass representing the lot shall be divided into three equal parts, each forming a 
composite sample; one for the purchaser , another for the supplier and the third as the reference sample to be used 
in case of dispute between the purchaser and the supplier.  
 
7.3.3  Individual samples  
The remaining portion of material in each gross sample shall be divided into three equal parts, each forming  
an individual sample. One individual sample from each gross sample in the lot shall be taken to constitute a  
set of individual samples. One set of individual samples shall be for the purchaser, another for the supplier and the 
third as the referenc e sample to be used in case of dispute between the purchaser and the supplier.  
 
7.3.4  Reference sample  
The reference samples shall consist of a set of composite samples and a set of individual samples. All the  
containers of reference samples shall bear the seal of both the purchaser and the supplier, and shall be kept at a 
place agreed upon between the two parties.  
7.4 Number of tests  
7.4.1  Tests for the determination of important characteristics, as specified in RS EAS 786 and RS EAS 377 - 
3 for the individual materi als shall be conducted separately on each of the individual samples.  
 
7.4.2  Tests for the determination of the other characteristics prescribed shall be conducted on the composite 
sample.  DRS 278: 2021  
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 7.5 Criteria for conformity  
7.5.1  For individual samples, for each of the char acteristics which has been determined on the individual  
Mean (x) =  Sum  of test  results  
Number  of test  results 
Range ( R) = Difference between the maximum and minimum value of the test results  
7.5.2  If the specification limit for the characteristics is given as a minimum, then the value of the expression 
(x –KR)shall be calculated from the relevant test results (see 7.5 .5). If the value so obtained is greater than or 
equal to the minimum limit, the lo t shall be declared as conforming to the requirement for that characteristic.  
7.5.3  If the specification limit for the characteristics is given as a minimum, then the value of the 
expression (x +KR)shall be calculated from the relevant test results (see 7.5 .5). If the value so obtained is greater 
than or equal to the minimum limit, the lot shall be declared as conforming to the requirement for that characteristic.  
7.5.4  If the characteristic has two -sided specification limit, then the values of the expression (x +KR)shall 
be calculated from the relevant test  results (see 7.5 .5). If the values so obtained lie between the two specification 
limits, the lot shall be declared as conforming to the requirement for that characteristic . 
7.5.5  The value of the factor K referred to in 7 .5.2 to 7.5 .4 shall be chosen in accordance with Table 
3depending upon the acceptable quality level.  
Table 3 — Value of K for different acceptable quality level  
 
Acceptable quality levels (Q);  per 
cent Value of K  
Q≤1 0.6 
1<Q≤2 0.5 
2<Q≤4 0.4 
 
7.5.6  For composite sample , for declaring the conformity of the lot to the requirements for all the remaining 
characteristics determined on the composite sample, the test result for each of the characteristicsshall comply with 
the relevant requirement specified in this Rwanda Standard.  
 DRS 278: 2021  
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 Annex  A 
(normative)  
 
Illustration of instrumentation units  
A.1 General  
All dimensions are in millimetres  
 
 
1A. SIN GLE COMPARTMENT  
FIG. 1A.  CLOSED -END SAMPLING TUBE (SPEAR), UNDIVIDED.  
 
 
 
 
 
 DRS 278: 2021  
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1B.   MULTI -COMPARTMENT  
 
FIG. 1B.  CLOSED -END SAMPLING TUBE (SPEAR), UNDIVIDED.  DRS 278: 2021  
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1C.    SINGLE COMPARTMENT  
 
FIG. 1C.  CLOSED -END SAMPLING TUBE (SPEAR), UNDIVIDED.  DRS 278: 2021  
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FiIG 2. DIPPER BOTTLE  
DRS 278: 2021  
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                    TYPE A                                                              TYPE B  
                                       FIG.3. BOTTOM -VALVED SAMPLING TUBE  
 
DRS  278: 2021  
 
Price based on  13 pages  
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