 DEAS 257 :2021  
ICS 59 .080.01  
 
© EA C 2021                                                                                                                          Second Edition 2021   
 DRAFT EAST AFRICAN STANDARD  
Textiles — Determination of moisture, total size,  ash, fatty and water -
soluble matter  
EAST AFRICAN COMMUNITY  
 
 
 
 DEAS 257 :2021  
ii © EAC 2021  – All rights reserved  
 Copyright notice  
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Violators may be prosecuted . DEAS 257 :2021  
© EAC 2021  – All rights reserved  iii 
 Content s Page 
Foreword  ................................ ................................ ................................ ................................ ............................  iv 
Introduction  ................................ ................................ ................................ ................................ .........................  v 
1 Scope  ................................ ................................ ................................ ................................ ......................  1 
2 Normative references  ................................ ................................ ................................ ............................  1 
3 Terms and definitions  ................................ ................................ ................................ ...........................  1 
4 Quality of reagents  ................................ ................................ ................................ ................................  1 
5 Determination of moisture  ................................ ................................ ................................ ....................  1 
5.1 Apparatus  ................................ ................................ ................................ ................................ ...............  1 
5.2 Procedure  ................................ ................................ ................................ ................................ ...............  2 
5.3 Calculation  ................................ ................................ ................................ ................................ .............  2 
6 Determination of total size  ................................ ................................ ................................ ...................  2 
6.1 Apparatus  ................................ ................................ ................................ ................................ ...............  2 
6.2 Reagents  ................................ ................................ ................................ ................................ ................  2 
6.3 Procedure  ................................ ................................ ................................ ................................ ...............  3 
6.4 Calculations  ................................ ................................ ................................ ................................ ...........  4 
7 Determination of ash  ................................ ................................ ................................ .............................  5 
7.1 Apparatus  ................................ ................................ ................................ ................................ ...............  5 
7.2 Procedure  ................................ ................................ ................................ ................................ ...............  5 
7.3 Calculation  ................................ ................................ ................................ ................................ .............  5 
8 Determination of fatty matter  ................................ ................................ ................................ ...............  5 
8.3 Procedure  ................................ ................................ ................................ ................................ ...............  6 
8.4 Calculation  ................................ ................................ ................................ ................................ .............  6 
9 Determination of water soluble matter  ................................ ................................ ................................  6 
9.1 Test specimens  ................................ ................................ ................................ ................................ ...... 6 
9.2 Conditioning of test specimens  ................................ ................................ ................................ ...........  6 
9.3 Apparatus  ................................ ................................ ................................ ................................ ...............  6 
9.4 Reagent  ................................ ................................ ................................ ................................ ..................  7 
9.5 Procedure  ................................ ................................ ................................ ................................ ...............  7 
10 Test report  ................................ ................................ ................................ ................................ ..............  7 
Bibliography  ................................ ................................ ................................ ................................ ........................  8 
 
 DEAS 257 :2021  
iv © EAC 2021  – All rights reserved  
 Forew ord 
Development of the East African Standards has been necessitated by the need for harmonizing requirements 
governing quality of products and services in the East African Community. It is envisaged that through 
harmonized standardization, trade barriers t hat are encountered when goods and services are exchanged 
within the Community will be removed.  
The Community has established an East African Standards Committee  (EASC)  mandated to develop and 
issue East African Standards  (EAS) . The Committee is composed of representatives of the National 
Standards Bodies in Partner States, together with the representatives from the public and private sector 
organizations  in the community .  
East African Standards are developed through  Technical Committees that are represen tative of key 
stakeholders including government, academia, consumer groups, private sector and other interested parties. 
Draft East African Standards are circulated to stakeholders through the National Standards Bodies in the 
Partner States. The comments r eceived are discussed and incorporated before finalization of standards, in 
accordance with the Principles and procedures for development of East African  Standards.  
East African Standards are subject to review, to keep pace with technological advances. Use rs of the East 
African Standards are therefore expected to ensure that they always have the latest versions of the standards 
they are implementing .  
The committee responsible  for this document is Technical Committee EASC/TC 061, Textiles, textile products 
and accessories . 
Attention is drawn to the possibility that some of the elements of this document may be subject of patent 
rights. EAC shall not be held responsible for identifying any or all such patent rights.  
This second edition cancels and rep laces the  first edition (EAS 257:2001 ), which has been technically revised. 
The main changes compared to the previous edition are as follows:  
— A clause on normative references has been added;  DEAS 257 :2021  
© EAC 2021  – All rights reserved  v 
 Introduction  
In the textile industry, yarns and fabrics undergo treatment s during manufacture in the course of which 
extraneous matter of various types is gathered by or added to the original textile material.  The standard, 
therefore, lays down standard methods for estimating the quantity of each and for determining the water -
soluble matter, which if present beyond certain limits in the textile materials adversely affect their quality.  
 DRAFT EAST AFRICAN STANDARD  DEAS 257 :2021 
 
© EAC 2021  – All rights reserved  1 
 Textiles — Determination of moisture, total size,  ash, fatty and water -
soluble matter  
1 Scope  
This D raft East African Standard  prescribes  methods for determining  moisture, total size, ash, fatty and water -
soluble matter in cellulosic textile materials  and their blends . 
The method for determination of  water -soluble matter is applicable to other textile fibres  
2 Normative references   
The followi ng 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.  
ISO 139, Textiles — Standard atmospheres for conditioning and testing  
ISO 3696, Water for analytical laboratory use — Specification and test methods  
3 Terms and definitions   
No terms and definitions are listed in this do cument.  
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 Quality of reagents  
Analytical grade reagents  shall be utilised  in the test s and grade 3 of water , as specified in ISO 3696  shall be 
used where the use of water as a reagent is intended.  
5 Deter mination of moisture  
5.1 Apparatus  
5.1.1 Drying oven  —  Capable of maintaining a temperature of 105 0C ± 3 0C.  
5.1.2 Weighing balance  — Capable of weighing to an accuracy of 0.001 g.  
5.1.3 Desiccator .  DEAS 257 :2021  
2 © EAC 2021  – All rights reserved  
 5.2 Procedure  
From the sample under test draw at least two test specimens each weighing approximately 3 g.  
5.2.1 Take a test specimen drawn as in 5.2 and weigh it accurately in a clean  and dry tared weighing bottle. 
Place the weighing bottle containing the test specimen in the drying oven and dry the specimen at 105 °C to 
110 °C to constant mass (see Note), the in a desiccator  and determine the oven -dry mass of the test 
specimen.  
NOTE  The mass usually be regarded as constant if the loss between two successive weighing, taken at an interval of 
30 min does not exceed by 0.1 per cent of the first of the two values.  
5.2.2 Similarly test the other test specimen(s).  
5.3 Calculation  
Calcula te the percentage of moisture content in the test specimen by the following formula:  
 
where;  
a original mass in g of the test specimen; and  
b oven -dry mass in g of the test specimen.  
5.3.1  Determine the mean of all values obtained in 5.8 and express it as moisture content of the material.  
5.3.2 Corrected invoice mass of cotton textile material shall be calculate by the following formula:  
 
where;  
L1 corrected invoice mass in g of the material  
L original mass in g of the material;  
b oven -dry mass in g of the test specimen; and  
a original mass in g of the test specimen.  
6 Determination  of total size  
6.1 Apparatus  
6.1.1  Soxhlet extractor  
6.1.2  Drying oven  — See 5.1.1  
6.1.3  Desiccator  
6.2 Reagents  
6.2.1  Trichloroethane of dichloromethane  DEAS 257 :2021  
© EAC 2021  – All rights reserved  3 
 6.2.2  Diastase  or other suitable desizing enzyme  
6.2.3  Sodium chloride  
6.2.4  Soap -soda solution  — Containing 20 g soap and 10 g of anhydrous sodium carbonate per litre. The 
soap shall contain not more than 5 per cent moisture and shall comply with the following c omposition in Table 
1, on dry basis.  
Table 1 — Composition of soap soda solution  
Free alkali (as Na 2CO 3), max.  0.3 %  
Free alkali (as NaOH), max.  0.1 %  
Combined fatty acids (as sodium salt), min.  85 %  
Titre of mixed fatty acids prepared from the soap, ma x. 30 0C 
Iodine value of fatty acids, max.  50 
6.3 Procedure  
From the sample under test, draw at least two test specimens each weighing approximately 5g.  
6.3.1  If the sample under test is yarn, cut each test specimen into pieces 15 cm long, form into sep arate 
bundles and tie each bundle loosely round the middle.  
6.3.2  If the sampled under test is fabric, trim each test specimen parallel to the directions of warp and weft 
and pull out five threads all round to form a fringe.  
6.3.3  Using test speci mens ot her than those drawn in 6 .3, determine the moisture content of the sample by 
the method prescribed in 3 and calculate its oven -dry mass.  
6.3.4  Take a test specimen as drawn in 6 .3 and extract it in a Soxhlet extractor for one hour with 
trichloroethane or eichloromethane, adjusting the rate of boiling to at least six hot extractions per hour.  
6.3.5  Treat the  extracted specimen in the manner prescribed in 6.3.5.1, 6.3.5.2 or 6 .3.5.3 depending on the 
type of the ingredients used in the size.  
6.3.5.1  In case it is known that the material is sized with a mixing containing starch but not tarmarind 
kernel powder, dip the specimen in a solution (weighing 20 times the mass of the specimen) containing 5 g of 
diastase and 10 g sodium chloride per litre at 50  0c and a t a pH of 6.5 to 7.7 (see Note). Allow the specimen to 
remain in the solution for one and a half hours. During this period, take it out from the solution and wring it by 
hand atleas t three times. At the end of the period remove the specimen, wash it thorou ghly four times in hot 
and cold water successively using 50 ml of water for each wash.  
NOTE The temperature and pH given for the desizing solution are the optimum for bacterial diastase. If any other 
type of desizing enzyme is used, then the temperature a nd pH shall be modified to that recommended by the supplier. As 
many enzymatic desizing agents slowly deteriorate in storage, care shall be taken to see that the sample of desizing agent 
at the time of test has still satisfactory desizing efficiency.  
If any doubt exists as to whether the size has been completely removed, the treatment with the enzymatic 
desizing solution shall be repeated, the specimen being again weighed after drying to constant mass at 105 
°C to 110 °C and the percentage loss in mass has  increased by not more than 0.25, then it may be 
considered that complete desizing has been effected, and the second value be accepted as the final value. If 
the value for the percentage loss in mass has increased by more than 0 .25, then the desizing treat ment shall 
be repeated until the value of percentage loss in mass does not differ from the previous figure by more than 
0.25.  
6.3.5.2  In case it is known that the material is sized a mix ture containing tarmarind kernel powder but not 
starch, boil the spec imen in the soap -soda solution (weighing 20 times the mass of the specimen) for 45 min, 
Wash it thoroughly first in hot water and then in cold water.  DEAS 257 :2021  
4 © EAC 2021  – All rights reserved  
 6.3.5.3  In case it is known that the material is sized with a mix ture containing both starch and tarmarin d 
kernel powder or in  case the ingredients used in the size are not known, desize  the specimen as prescribed in 
6.3.5.1 and treat it further as prescribed in 6.3.5.2.  
6.3.6  Dry the s pecimen treated as above  (see 6.3.3, 6.3.4 and 6 .3.5) in the drying oven  at 105 °C to 110 
°C to constant mass (see Note under 5.2.1), and weigh accurately.  
6.3.7  Similarly repeat the test with other test specimen(s).  
6.4 Calculations  
Calculate the percentage of total size expressed on the oven -dry mass of the unsized material  by the following 
formula:  
 
where,  
X = total size, percent by mass;  
a = oven -dry mass (calculated) in g of the test specimen containing the size;  
 
experimentally (on unsized) for adjusting the value of b, due to loss of natural constituents sustained b y the 
test specimen dur ing treatment as prescribed in 6.3.3, 6 .3.4 and 6.3.5;  
b = oven -dry mass in g of the test specimen determined as in 6 .3.6; and  
c = oven -dry mass in g of blank af ter treatment as prescribed in 6 .3.3, 6.3.4, 6.3.5 and 6 .3.6.  
NOTE No rmally k cannot be determined experimentally as a comparable unsized control blank is usually not available, 
particularly so in the case of fabric. In the absence of a control blank, k shall be taken as equal to 1.03 for grey cotton, 
1.02 for unbleached vi scose and 1.00 for all other fibers.  
6.4.1  Determine the mean of all values as obtained in 6.4  
6.4.2  Total size of cotton textile material expressed as a percentage of:  
i) the original mass of the material;  
ii) the conditioned mass of the material; and  
iii) the corrected invoice mass of the material, may be calculated by the following formulas:  
 
 
 
where,  
X1 total size as a percentage by mass of the original mass of the material;  DEAS 257 :2021  
© EAC 2021  – All rights reserved  5 
 X2 total size as a percentage by mass of the conditioned mass of the material;  
X3 total si ze as a percentage by mass of the corrected invoice mass of the material;  
a oven -dry mass (calculated) of the test specimen containing the size.  
k correction factor b (see 6.4);  
a1 original mass in g of the test specimen; and  
a2 conditioned mass in g o f the test specimen.  
7 Determination  of ash  
7.1 Apparatus  
7.1.1  Silica or porcelain crucible  with lid.  
7.1.2  Muffle furnace  — Capable of being heated to 700 °C.  
7.2 Procedure  
From the sample under test, draw at least two test specimens each weighing a pproximately 5 g.  
7.2.1  Determine the moisture content of the sample by the method prescribed in Clause 5, not using the 
test specimens drawn as in 7.2. Cut one test specimen drawn as in 7.2 into small pieces, place all the pieces 
of the test specimen in a silica or porcelain crucible and weigh accurately. Slowly ignite the test specimen in 
the crucible over a Bunsen flame, taking care to avoid flaming. Transfer the crucible to the muffle furnace and 
ash at 700 °C for one hour or more until it attains  cons tant mass (see Note under 5.2.1) and note the mass 
accurately.  
7.2.3  Similarly repeat the test with the remaining test specimen(s).  
7.3 Calculation  
7.3.1  Calculate the percentage of ash by the following formula:  
 
where;  
a mass in g of the residue (ash);  and  
b oven -dry mass (calculated) in g of the test specimen.  
7.3.2 Determine the mea n of all values as obtained in 7 .3. 
8 Determination  of fatty matter  
8.1 Apparatus  — same as in 6.1.  
8.2 Reagent  — Trichloroethane or dichloromethane.  DEAS 257 :2021  
6 © EAC 2021  – All rights reserved  
 8.3 Procedure  
From the sample under test draw at least two test specimens each weighing approximately 5 g.  
8.3.1  Take one test specimen drawn as in 8.3 and weigh it accurately in a clean, dry, tared weighing bottle. 
Place the weighing bottle containing the test specimen i n the drying oven maintained at 105 °C to 110 °C and 
dry the specimen to  constant mass (see Note under 5.2.1) and note the mass.  
8.3.2  Transfer the specimen to a thoroughly dry and clean thimble (previously extracted in a Soxhlet 
extractor with trichloroe thane or dichloromethane). Place the thimble with the test specimen in the Soxhlet 
extractor. Take adequate quantity of trichlororoethane in tared Soxhlet extraction flask and assemble the 
Soxhlet extraction apparatus. Heat it on a water bath or electric h ot-plate at such a rate that at least six hot 
extractions occur per hour. Keep the volume of the solvent fairly constant by adding enough of trichloroethane 
to make up for any loss due to evaporation. Continue extraction 4 h. Cool and disconnect the extrac tion flask.  
8.3.3  Recover the bulk of the solvent by distillation and evaporate the extract to dryness on a steam bath. 
Further dry the contents in the drying oven at 105 °C to 110 °C to consta nt mass (see Note under 5.2.1) and 
determine its mass.  
8.3.4  Similarly repeat the test with the remaining test specimen(s)  
8.4 Calculation  
8.4.1  Calculate the percentage of fatty matter by the following formula:  
 
where;  
b mass in g of the extract (see 8.3.3); and  
a oven -dry mass in g of the test specimen (see 8.3 .1) 
8.4.2 Determine the mean of all values as obtained in 8.4. 
9 Determination of water soluble matter  
9.1 Test specimens  
From the test sample, cut out at least two test specimens each weighing about 10g. Cut the test specimens 
into small pieces.  
NOTE I f the sample under analysis is loose fiber, take about 5 g of the test specimen.  
9.2 Conditioning of test specimens  
Prior to test, the test specimens shall be conditioned for 24 h in accordance with  ISO 139 . However, in case of 
fabrics which weigh more t han 270 g/m2, the test specimens shall be conditioned for 48 h.  
9.3 Apparatus  
9.3.1  Flat-bottomed flasks of suitable capacity with a glass stopper incorporating a stop -cock.  
NOTE  The flasks that are used for the preparation of the extract shall not be u sed for any other purposes.  DEAS 257 :2021  
© EAC 2021  – All rights reserved  7 
 9.3.2  Water -cooled Reflux Condenser  
9.4 Reagent  
9.4.1  Distilled water  — Conforming to  ISO 3696 .  
9.5 Procedure  
9.5.1  Condition the test specimens to moisture equilibrium in the standard atmosphere (see 9.2.1) and 
weigh and w eigh accurately each test specimen.  
9.5.2  Put a test specimen in the flask and add sufficient amount of water to it to make a liquor to material 
ratio of 20:1 (see Note  below ). Connect the flask to the condenser and bring rapidly to the boil and continue t o 
boil the liquor gently for 60 min.  Disconnect and remove the flask while the liquor is still boiling and close it 
immediately with the glass stopper fitted with a top -cock.  
Rapidly cool the flask to room temperature (20 ± 20 °C). Do not remove or open the tap until ready for 
filtration. Reject any extract where the flask is not under vacuum at the time of opening. Filter the extract 
through a suitable filter paper (Whatman No. 42 is suitable) and evaporate a measured portion of the extract 
to dryness in  a tared vessel. Dry the residue to constant mass at 105 °C to 110 °C.  
NOTE  If the test specimen is wool, the liquor to material ratio shall be 50:1.   
9.5.3  Calculate the water -soluble matter as a percentage of the conditioned mass of the specimen by the  
following formula:  
 
where,  
p percentage of water -soluble matter;  
W2 mass, in g, of the residue (see 9.5.2); and  
W1 mass, in g, of the conditioned test specimen (see 9.5.1)  
9.5.4  Repeat the test as given in 9.5.2 with the remaining test specimen(s) and  calculate the percentage of 
water -soluble matter in each test specimen.  
10 Test report  
The test report shall include the following information:  
a) moisture content, percent;  
b) size, percent;  
c) ash content, percent, and  
d) the average of the values obtained as in 9.5.3 and 9.5.4 as the percentage of water -soluble matter of 
the textile.  DEAS 257 :2021  
8 © EAC 2021  – All rights reserved  
 Bibliography  
EAS 257 :2001, Methods for estimation of moisture total size for finish, ash, fatty matter and determination of 
water -soluble matter in textiles  
 DEAS 257 :2021    
 
© EAC 2021  – All rights reserved  
  
  