TDC9(6785 ) P3 
  
 
DRAFT TANZANIA STANDARD  
 
 
 
 
 
Textiles – Reusable fabric face masks – Specification  
 
 
 
 
 
 
 
 
 
TANZANIA BUREAU OF STANDARDS  
 
 
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 FOREWORD  
This Draft Tanzania Standard is being developed by the Hospital Textiles  Technical Committee under 
supervision of the  Textile and Leather  Divisional Standards Committee and it is in accordance wit h the 
procedures of the Bureau.  
In the preparation of this standard assistance has been obtained from the following standards:  
       TZS 2005: 2017 Textiles – Dust m ask — Specification  
       KPAS 2917:2020 Reusable cloth mask — Specification  
In reporting the r esult of a test or analysis made in accordance with this Draft Tanzania S tandard if the 
final value, calculated or observed is to be rounded off, it shall be done in accordance with TZS 4 
Rounding off numerical values.  
 
 
 
 
 
 
 
 
 
  
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1. SCOPE  
This Draft Tanzania Standard specifies performance requirements , sampling  and test methods for  
reusable fabric  face masks  for general public use . 
 
2. NORMATIVE REFERENCE  
For the purpose of this Draft Tanzania Standard, the following references shall apply. For dated 
references, only the edition cited applies. For undated references, the latest edition of the referenced 
document (including any amendments) applies:  
 
TZS 21, Textiles – Woven or knitted fabrics – Determination of mass per unit length and per           
unit area . 
TZS 24, Textiles — Test for colour fastness to washing with soap or soap and soda . 
TZS 137 , Textiles - Woven, knitted fabrics and garments - Determination of dimensional 
change - Machine method.  
TZS 138, Textiles — Test for colour fastness to rubbing . 
TZS 280, Textiles – Test for colour fastness – Colour fastness to perspiration.  
TZS 327, Textiles – Binary fibre mixtures – Quantitative analysis . 
BS EN  14683  Medical face masks – Requirements and test methods  
 
3. TERMS AND DEFINITIONS  
For the purpose of this Draft Tanzania Standard, the following definitions shall apply:  
3.1 Face mask   
device that you wear over your face to prevent yourself from breathing  in and spreading germs  in 
air.,  
 
3.2 Coated fabrics  
fabric that has been treated to make them longer lasting, stronger, and more weather resistant. 
The most common coating is polyethylene, other coatings include rubber and plastic resins, 
polyvinyl chloride, a crylic,  paraffin, natural beeswax based wax  etc. 
 
4. REQUIREMENTS  
 
4.1 General  
4.1.1  Materials  
 Reusable fabric face mask  shall be manufactured from cotton, poly -cotton or 
polypropylene fibre materials . Coated fabric materials shall not be used.  
 
4.1.2  Dyes and pigments  
For dyed or printed fabrics, dyes  and pigments  used shall not be carcinogenic . 
 
  
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 4.1.3  Design and constructions  
The reusable fabric face mask  shall have three  layers; the innermost layer , outermost layer  and 
middle layer.  
The reusable fabric face mask  shall be designed in a way  that it is comfortable to wear, fit closely 
over the nose, mouth and chin of  the wearer and which ensures that the mask fits at the sides.  
  
4.1.4  Workmanship  
The reusable fabric face mask  shall be free from defects that affect their appearance and 
serviceability , free from marks, holes, spots or stains incurred in the making up. The masks shall 
be manufactured under hygienic conditions.  
4.2 Specific requirements   
The reusable fabric face mask  shall not disintegrate, split or tear during intended use and shall be 
made of three  layer fabrics.  
The reusable fabric face mask  shall co nform to the requirements specified in Table 1  below : 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
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 Table 1 – Requirements for reusable fabric face mask . 
S/N Characteristics  Requirements  Test Method  
1.  Fibre composition  
 
a) Inner most layer   
100% Cotton   
TZS 327  
b) Outer most layer  Blend of cotton and 
polyester   
c) Middle layer  Polypropylene , polyester  
or their blend.  
2.  Differential pressure 
(breathability), Pa, max.   100 Annex A  
3.  Bacterial filtration efficiency, %, 
min 70 TDC 9 (6787)  
4.  Microbial cleanness, cfu/g, max  30 BS EN 14683   
5.  Dimensional change , %, Max 
i) After five normal washings  
 
ii) After three dry washings    
3 
2  
TZS 137  
 
6.  Colour fastness : 
a) To washing , min   
 
4  
TZS 24  
b) To rubbing, min  
i) Wet 
ii) Dry    
4 
4  
TZS 138  
c) To perspiration, min  4 TZS 280  
 
5. PACKAGING AND LABELLING  
 
5.1 Pack aging   
5.1.1  Primary package  
The reusable fabric face mask  shall be packed as single unit pack of appropriate material .  
 
5.1.2  Secondary package  
Single unit packs shall be packed in secondary package in agreement between the manufacturer and 
buyer  
 
5.2 Labelling   
For mass production, e ach piece of the reusable fabric face mask  shall be legibly marked with the 
following information:   
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 a) Name of the product (i.e. reusable fabric face mask ). 
b) Manufacturer ’s name, initials or trade -mark.  
c) Size of the mask (i.e. Small (S), M edium (M), Large (L) or Extra Large (XL) ) 
d) Month and year of manufacture  
e) Batch /lot  number  
f) Number of pieces in a single package.  
g) The word ‘Wash and dry before use’.  
 
 
6 SAMPLING AND CRITERIA FOR CONFORMITY  
6.1 Lot  
All reusable fabric face mask  of the same material and produced under similar conditions of 
manufacture shall constitute a lot . 
 
 
6.2 The number of  reusable fabric face mask  to be selected at random from a lot shall be as follows:  
  Table 2 – Sampling plan  
S/N Lot size  Sample size  
1.  Up to 25  3 
 
2.  26 to 50  5 
 
3.  51 to 150  8 
 
4.  151 to 300  13 
 
5.  301 to 500  20 
 
6.  501 to 1000  32 
 
7.  1001 and above  50 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
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 ANNEX A  
(normative)  
METHOD FOR DETERMINATION OF BREATHABILITY (DIFFERENTIAL PRESSURE)  
A-1 PRINCIPLE   
A device which measures the pressure differential required to draw air through a measured surface 
area at a constant air flow rate is used to measure the air exch ange pressure of the reusable fabric 
face mask material, as shown in Fig.1. Water -filled manometers (M1 and M2) are used to measure 
the pressure differential. A flow meter is used for measurement of the air flow.  
 
 
KEY 
1 – Air inlet                                                   4 – Filter material                                   7 – Vacuum pump  
2 – Flow meter                                             5 – Manometer M2  
3 – Manometer M1                                       6 – Valve  
Figure 1 – Apparatus for measuring air resistance  
 
 
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 An electric vacuum pump draws air through the  apparatus and a needle valve is used to adjust the air  
flow rate.  
 
A -2 APPARATUS  
A -2.1 Flow Meter , capable of measuring an air flow of 8 litre/min.  
A-2.2 Manometers , M1 and M2.  
A-2.3 Electric Vacuum Pump  
A-2.4 Valve  
 
A-3 TEST SPECIMENS  
Test specimens shal l be complete masks or shall be cut from masks. Each sp ecimen shall be able to 
provide five different circular te st areas of 2.5 cm in diameter. The nu mber of specimens that shall be 
tested shall be five. 
 
A-4 PROCEDURE  
A-4.1 The test specimen is placed across the 2.5 cm  diameter orifice (total area 4.9 cm2) and clamped 
into place so that the tested area of the specimen will be in  line and across the flow of air.  
A-4.2 The pump is started and the flow of air adjusted  to 8 litres/minute.  
A-4.3 The manometers M1 and M2 are read and  recorded.  
A-4.4 The procedure described in steps B-4.1 through B-4.3 is carried out on five different areas of  the 
mask and the readings averaged . 
A-5 CALCULATION OF DIFFERENTIAL PRESSURE  
For each test speci men, calculate the differential pressure, ΔP as follows:  
ΔP = (X m1 - Xm2) / 4.9 
 
Where  
X m1 = water pre ssure, in mm, manometer 1, mean of five test areas, low pressure side of the material;  
X m2 = water pre ssure, in mm, manometer 2, mean of five test a reas, high pressure side of the material;  
4.9 = area of the test material, in cm2; and  
ΔP = pressure differential per cm2 of test material expressed as mm of water.  
 
  
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 A-6 TEST REPORT  
The test report shall include the following information:  
a) Flow rate during testing; and  
b) Differential pressure for each test specimen.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
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 ANNEX B 
(Informative)  
B-1 – Handling of the reusable fabric face mask . 
Thoroughly wash and iron the mask before wearing it.  Wash your hands thoroughly before wearing the 
mask.  After four hours of use or as soon as the mask becomes wet or humid, switch to another mask 
and wash  the used mask.  Never reuse a mask after single use without washing  it. 
B-2 – How to remove the reusable fabric face mask .  
Do not touch the front or any other surface of the mask, remove it using its strings from behind . Always 
untie the lower string below and then the  upper  string . After removal, store it in an appropriate container, 
immediately clean your hands with 6 0% alco hol based hand sanitizer or with soap and running water 
for 20 seconds .  Soak  it directly into a soap solution or boiling water to which salt has been added after 
every single  use. 
B-3 –  How to wash  the reusable fabric face mask  after every single use.  
a) Thoroughly wash the mask in soap and warm water and leave it to dry in hot sun for at least 5 
hours; if it is not a  sunny day , follow o ption b:  
b) Place the mask in water in a pressure cooker and boil it for at least 10 minutes and leave it to dry. 
Adding sa lt to the water is recommended. In the absence of a pressur e cooker, you may boil the 
fabric  mask in hot water for 15 minutes; If you do not have access to a pressur e cooker/boiling 
water, follow o ption c:  
c) Wash the fabric mask with clean water and soap and iron it  for up to five minutes.  
 
 
 
 
 
 
 
 
 
 
 
 
 
  
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 Bibliography  
Recommended Guidelines Fabric Face Masks Manufactured by South Africa’s Clothing and Textile                                  
Manufacturing Industry for General Public Use.  
WHO Interim Guidance – Advice on the use of masks in the context of COVID -19.