Draft standard for Technical Commitee Meeting  CDC 11 ( 301)  DTZS 
         
                                                                                                     
   
DRAFT TANZANIA STANDARD  
 
 
  
 
 
 
 
 
 
 
Flexible polyurethane foam mattresses - Specification  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
             
  
  
              TANZANIA BUREAU OF STANDARDS   
 
  
 
 
© TBS 2021 All right Reserved                                                                 First Edition 2021                                                       
Draft standard for Technical Commitee Meeting   
  
0 Foreword  
  
 
This Draft Tanzania Standard is being developed by Plastic and Plastic Products Technical 
Committee under supervision of the Chemical Division Standards Committee and it is in accordance 
with the procedures of the Bureau 
 
This Draft Tanzania Standard is the third edition of   flexible polyurethane foam mattresses – 
specification. 
  
This Draft Tanzania Standard has been prepared with assistance drawn from the following 
documents:  
  
 
KS 376: Part 0:2013 Specification for flexible polyurethane foams, published by Kenya Bureau 
of Standards  
 
KS 376: Part 1:2013 Specification for flexible polyurethane (polyether) foams, published by 
Kenya Bureau of Standards 
 
IS 1051: 2018 Specification for flexible polyurethane foam for domestic mattresses, published 
by India Bureau of Standards  
 
             SABS 1291: Part 1 Mattresses having unsupported polymeric covers, published by South   
              African Bureau of Standards 
 
SABS 1291: Part 2: 1993 Foam mattresses for domestic and hotel use,  published by South 
African Bureau of Standards 
 
BS 1877: Part 10: 2011, Specification for mattresses and bumpers for children's cots,  
perambulators and similar domestic articles,  published by British Standards Institution  
Various specifications of local spring mattresses manufacturing companies    
 
The assistance obtained from the above source is hereby acknowledged with thanks. 
 
For the purpose of deciding whether a particular requirement of this Tanzania Standard is complied 
with, the final value observed or calculated, expressing the result of a test or analysis shall be 
rounded off in accordance with TZS 4 . 
 
 
  Draft standard for Technical Commitee Meeting   
  
 
DRAFT TANZANIA STANDARD                      TBS/CDC 11 (301) DTZS 
 
 
 
Flexible polyurethane foam  mattresses – specification 
 
  
1 Scope   
This Draft Tanzania Standard specifies requirements, sampling and test methods of flexible 
polyurethane foam mattresses. 
 
2 Normative references  
The following documents, in whole or in part, are normatively referenced in this document and are 
indispensable for its application. For dated references, only the edition cited applies. For undated 
references, the latest edition of the referenced document (including any amendments) applies.” 
     
TZS 4, Rounding off numerical values  
 
TZS 20/ISO 13934-2 , Textiles - Tensile properties of fabrics — Part 2: Determination of 
maximum force using the grab method 
 
TZS 22/ ISO 13934-1, Textile - Tensile properties of fabrics - Part 1: Determination of 
maximum force and elongation at maximum force using the strip method 
 
TZS 43/ ISO 105-C10, Methods for the determination of colour fastness of textile Materials  
  to washing 
  
TZS 138/ ISO 105-D01, Method for determination of colour fastness of textile materials  
 to dry   cleaning 
 
TZS 359, Methods of test and sampling for Flexible polyurethane foam 
 
            
            
 
 
  Draft standard for Technical Commitee Meeting   
  
3 Terms and definitions  
For the purpose of this Draft Tanzania Standard, the following definitions shall apply:  
3.1 block   
mass of polyurethane foam formed by a free-rising foam process, in its original form prior to 
conversion. 
 
3.2 bursting strength 
the force required to rupture a fabric by distending it with pressure applied at right angles to the plane 
of the fabric 
 
3.3 breaking strength 
the maximum load (or force) supported by a specimen in a tensile test carried to rupture 
 
3.4 defective     
foam that fails in one or more respects to comply with the relevant requirements of the specification 
 
3.5 polyurethane foam    
the foam in which the polyol component is either polyether or polyester and produced by the reaction 
of polyol with an organic polyisocyanate in the presence of water, and that may include catalysts, 
surface-active agents, auxiliary blowing agents, fillers plasticizers, colourants, and any other additives 
that do not adversely affect the properties of the foam.  
 
3.6 lot    
not less than 1 m3 and not more than 100 m3 of foam of the same grade, and nominal dimensions, 
from one manufacturer, submitted at any one time for inspection and testing. 
 
3.7 tick  
a suitable outer cover that provides a comforting top layer of the mattress  
 
3.8 warp 
yarns / threads lying lengthways in a fabric as woven 
 
3.9 weft 
yarns / threads lying width ways in a fabric as woven (at right angles to the warp) 
 
3.10 yarn 
a generic term for a continuous strand of textile fibres or filaments without twisting, suitable for plying, 
knitting, braiding, weaving or otherwise intertwining to form a textile end product   Draft standard for Technical Commitee Meeting   
 4 Requirements  
4.1 General requirement  
4.1.1 The grades of flexible polyurethane foam mattress shall be in four grades: 
(i)  Light duty grade   
(ii) Medium duty grade   
(iii) Heavy duty grade 
(iv) Superior heavy duty grade  
 
4.1.2 Flexible polyurethane foam shall not contain impurities or harmful residues such as amines 
which are volatile and driven off by heat generated in the formation of foam. 
 
4.1.3 Adhesive used shall be either nitrile or neoprene based. If neoprene based adhesives are 
used, it shall not have acidity of more than pH 3.5. The adhesives shall be able to withstand heat 
and moisture treatments as effectively as the foam itself.  
 
4.1.4 The foam core shall be clean in appearance and free from any objectionable odour and any 
residual amines likely to be harmful to human tissues.  
 
4.1.5 The mattress core shall be flexible polyurethane foam of polyester or polyether type which is 
defined as expanded cellular product produced by interaction of polyhydroxy compound, water and 
isocyanate. 
 
4.1.6 The foam shall consist of cells of uniform characteristics which are essentially open and inter- 
connecting. 
 
4.2 Specific requirement  
    
4.2.1 Flexible polyurethane foam mattresses shall conform to the specific requirements given in Table 
1. 
Table 1 — specific requirements 
SL. No Characteristic Requirement Test method 
i Colour  report TZS 359  
ii Compression set ,%, max Light duty grade 12 
Medium duty grade 10 
Heavy duty grade 8 
Superior heavy duty grade 5 
iii 
 
 
 Density, kg/m3 , min Light duty grade 16  
Medium duty grade 23 
Heavy duty grade 27 
Superior heavy duty grade 32 
iv Durability,%, max 40 
v Elongation at break 
i) Original, %, min.  
  
ii) After heat aging, 
retention of original, 
%, min.     
200 
 
 
80 TZS 359 Draft standard for Technical Commitee Meeting   
   
iii) After humid aging, 
retention of original, 
%, min.  
   
80 TZS 359 
vi Flammability (a) no 
specimen shall 
burn for 3 min 
or more; and 
(b)   no 
specimen shall 
burn beyond 
the gauge line Annex A 
vii Hardness factor,  Light duty grade 3.6 - 14.4  Annex B 
Medium duty grade 3.6 -14.4 
Heavy duty grade 3.6 -14.4 
Superior heavy duty grade 3.6 -14.4 
viii Heat ageing,  retention of original  ,%, min 80 TZS 359 
ix Porosity report Annex C 
x Tensile strength, 
N/mm2,min Light duty grade 0.069 TZS 359 
Medium duty grade 0.083 
Heavy duty grade 0.098 
Superior heavy duty grade 0.118 
 
4.2.2 The cover of flexible polyurethane foam mattresses shall be of a woven ticking, or a knitted 
ticking and shall conform to the specific requirements given in Table 2 when tested in accordance with 
the methods prescribed therein. 
Table 2 - specific requirements for ticking 
SL. No Characteristic  
Requirement Test method 
i)  
 
 
Breaking 
strength 
(woven 
ticking) 
N, min. 
 
 
 
 
 
 
  
 Light mediu
m  heavy TZS 22/ ISO 
13934-1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Polyester Warp 350 450 600 
Weft 280 300 350 
Nylon Warp 350 450 700 
Weft 280 300 350 
Cellulosic  Warp 250 300 450 
Weft 160 200 280 
Polyester/ 
Nylon/Cell 
ulosic 
Blends Warp 300 350 500 
Weft 180 200 250 Draft standard for Technical Commitee Meeting   
     
 
Bursting strength (knitted  
ticking), KPa, min.  Polyester 200  TZS 20/ ISO 
13934-2 
Nylon 200 
Cellulosic  150 
Polyester/ 
Nylon/Cell 
ulosic 
 160 
ii)  
 
Mass in g/m2 (min.)  
 Light medium heavy Annex D 
Polyester 40 60 120 
Nylon 40 60 120 
Cellulosic  85 110 200 
Polyester/ 
Nylon/Cell 
ulosic 
Blends 60 80 150 
iii) Colour fastness to 
washing  Change in 
colour, rating, 
min.  
 
              4 TZS 43/ ISO105-
C10 
Staining of 
transfer cloths, 
rating, min 
iv) Colour fastness to dry-
cleaning Change in 
colour, rating, 
min.  
 
              4 TZS 138/ ISO 
105-D01 
Staining of 
transfer cloths, 
rating, min 
v) Flammability To comply with 
flammability requirements 
given in vi of table 1 Annex A Draft standard for Technical Commitee Meeting   
 4.2.3 The dimensional requirements of the foam mattress supplied in the form of blocks, trimmed 
blocks, slabs or sheets cut from trimmed blocks, or other shapes cut from any of these forms shall 
be as shown in Table 3 when tested in accordance with the method specified therein. 
Table 3 - Requirements for dimensions  
S/No. Characteristic Requirement, 
mm Tolerance, 
Mm Test method 
I Length 1800-2000 - 0 
+40  
TZS 359 (see clause 2) 
Ii Width 750 - 900 -0 
+10 
901 - 1350 -0 
+25 
1351- 2000 -0 
+40 
Iii Thickness 75 -150 -0 
+5 
 
5 Sampling   
5.1 Representative samples shall be taken randomly from the factory, market or elsewhere and 
tested for compliance with the standard as prescribed in clause 9 of TZS 359.  
6 Packing and marking  
6.1 Packing  
6.1.1 Each mattress shall be packed in a suitable transparent material and in case; plastics 
coverings are used as packaging for a mattress, the plastic cover shall be conspicuously marked 
with a warning to the effect that the covering should be kept away from children.   
 
NOTE 1 - An example of suitable wording is as follows: To avoid danger of suffocation, remove 
these plastics cover before using mattress. The cover should then be destroyed or kept away from 
children.  
6.1.2  Plastics used for packaging shall be not less than 30 microns thick   
  
6.2  Marking  
  
6.2.1 Flexible polyurethane foam mattresses shall be indelibly and legibly marked in the outer upper 
waist of the mattress or a label attached on it, with the following descriptions:  
  
a) Grade of foam mattress, 
b) The nominal length, width and thickness, 
c) Registered trade name of the product if any, 
d) Name of the manufacturer, 
e) Batch number/lot number and date of     
manufacture, 
f) Country of origin. Draft standard for Technical Commitee Meeting   
  
NOTE 2 - The TBS Certification Mark may be used by manufacturers only under license from TBS. 
Particulars of conditions under which the licenses are granted may be obtained from TBS offices.  
  
  
  
  
  
  
  Draft standard for Technical Commitee Meeting   
 Annex A  
(Normative)  
DETERMINATION OF FLAMMABILITY 
 
A.1 APPARATUS  
  
An apparatus as shown  schematically in Figure 1 A and consisting of a heat-resistant glass tube 
(chimney) in which a test specimen can be mounted, the base of the tube being connected to 
metered supplies of oxygen and nitrogen.  The glass tube shall have a diameter of at least 75 mm 
and a height of at least 450 mm, and shall have at its base a bed of glass beads (or other inert 
particles) that will mix and distribute the incoming gases.  The tube shall also contain a clamp that is 
capable of holding a test specimen (vertically) that the top of the specimen is at least 100 mm below 
the top of the tube. 
  
The oxygen and nitrogen used shall be of commercial grade (or better) and shall be supplied to the 
base of the glass tube through individual metering devices that enable the volumetric flow of each 
gas to be measured with an accuracy of 1 per cent or better. 
 
A.2 TEST SPECIMENS   
 
From the appropriate slab, pieces of total volume at least 0.01 m3 cut five specimens each of size 
12.5 + 0.5 mm x 12.5 + 0.5mm x 130 mm and draw a gauge line across each specimen 75 mm from 
the end that is to be positioned uppermost in the apparatus. 
 
A.3 PROCEDURE   
  
Clamp a test specimen in the holder of the apparatus so that it is held vertically in the center of the 
glass chimney.  Open the valves of the gas cylinders and adjust the flow so that the oxygen content 
of the gas mixture is 20 + 0.2  per cent and that the flow rate up the glass chimney (as calculated 
from the volumetric flow rate divided by the cross-sectional area of the chimney) is 40 + 10 % mm/s.  
Allow the gas to flow for at least 30 s and then, using a small gas flame at the end of a tube, ignite 
the test specimen so that the whole of the upper surface is burning.  Note whether the specimen 
burns for 3 min or longer and if not, whether or not the specimen has burned to below the 75 mm 
gauge line.  Repeat the test with the remaining four specimens. 
 
 
 
 
 
FIG. 1 A - GENERAL ARRANGEMENT OF FLAMMABILITY TEST APPARATUS 
 
Draft standard for Technical Commitee Meeting   
 Annex B  
(Normative)  
DETERMINATION OF HARDNESS FACTOR 
  
 B.1 APPARATUS   
   
A machine consisting of a flat circular indentor foot of thickness 10 mm, having the bottom edge 
rounded to a radius of 1 mm and a contact area of 322.5 cm, and that can be raised or lowered at a 
speed of 100"  20 m/m min and a base-plate that has 6.0 mm diameter perforations at 20 mm 
centres. The indentor foot is connected through a swivel joint to two gauges, one of which is capable 
of recording the force exerted by the foot upon the specimen and the other the distance travelled, 
relative to the base-plate. 
 
B.2. TEST SPECIMEN   
   
From the appropriate slab, pieces of total volume at least 0.01 m3 cut one rectangular specimen of 
size 380 mm x 380 mm x 50 mm. For a sample of thickness less than 50 mm, specimens of 
thickness at least 15 mm may be plied together (without the use of an adhesive) to give a total 
thickness of 50 mm. 
 
B.3 PROCEDURE   
   
Place the specimen centrally under the indicator foot and lower the foot into contact with the 
specimen and record the distance between the foot and the base-plate.  Flex the specimen twice by 
lowering the foot 35 mm then allow the specimen to recover for 10 min under no load. 
 
Lower the foot until a force of 5 N  is recorded on the gauge, record the distance travelled, and 
calculate, as follows, the thickness of the specimen under this load: 
  
 Thickness of specimen, mm = A ― B 
  
 where, 
  A   = the distance of the foot from the base-plate before flexing, in mm; 
   
  B   = the distance travelled by foot, in mm. 
 
 
Then lower the foot until the specimen is compressed to 60 per cent of its calculated thickness and 
note the force recorded on the gauge after 60 s. 
 
B. 4 CALCULATION  
   
Calculate, as follows, the hardness factor of the specimen, and record this value as the hardness 
factor of the sample: 
 
  Hardness factor = 0.102 x force, in newton’s required to produce 40 per cent compression. 
 
 
  
  
  
  
  
  
  Draft standard for Technical Commitee Meeting   
 Annex C  
(Normative)  
DETERMINATION OF POROSITY 
 
C.1 APPARATUS 
  
The apparatus consists, essentially, of a specimen holder connected through a flow meter to a 
supply of clean dry air. The apparatus shall include means for precise control of air flow rate and a 
manometer connected between the specimen holder and the flow meter. The specimen holder shall 
consist of a circular container, of internal diameter 38 mm and depth 25 mm, that has an air inlet of 
diameter 25 mm in the center of its base, and a cover with a central aperture of diameter 25 mm. 
The cover shall form an airtight seal with the top of the container, and the entire apparatus shall be 
free from leaks. 
 
C.2 TEST SPECIMENS 
 
From the appropriate slab ( see C.4.1) cut four cylindrical specimens each of diameter 38 mm and 
height 25 mm.  
 
C. 3. PROCEDURE 
 
Level the manometer and set it at zero. Insert the test specimen holder and replace the cover. Turn 
on the air supply and adjust it to obtain a pressure in the apparatus (as recorded by the manometer) 
of 125 Pa. When the pressure reading is steady, note the rate of air flow recorded by the flow meter. 
Repeat the test with the remaining three specimens. Calculate the porosity of each specimen as 
follows: 
 
Porosity, m3 /s.m2   = 2040 F 
 
where,  
 
F   =   the flow rate, in m3 / s. 
 
Record the mean of the four results as the porosity of the sample. 
 
 
C.4     Preparation of Test Samples and Test Specimen  
 
C.4.1 From each sample obtain, as follows, a test sample for each test given in the Appendices. 
 
Using a fine-toothed saw or rotary slicer (but not a heated wire), cut across the direction of rise of the 
foam (as determined by microscopical examination) a slab of suitable size and of the same 
thickness as that of the test specimens required for the relevant test, and that is free from skin. 
 
NOTE:  Slabs of the following thickness are required: 12.5  mm, 25 mm, 50mm. 
 
C.4.2 When cutting the test specimens, use a die, a saw, or a knife, as appropriate, and 
ensure that the top and bottom surfaces of each specimen are flat and parallel to each 
other, that the sides are vertical, and that the test specimens are free from skin. 
 Draft standard for Technical Commitee Meeting   
 Annex D  
(Normative)  
Test method for mass per unit area 
  
D.1 Principle  
 
This method specifies the procedures for determining the mass per unit area of woven fabrics 
(including those of the stretch type), knitted fabrics, nonwoven fabrics, composite fabrics and narrow 
fabrics.  
 
D.2 Apparatus   
 
D.2.1 Table  that has a smooth flat surface and is of a size that exceeds that of the fabric to be 
measured  
 
D.2.2 Cutter , that is capable of cutting a square or circular specimen of area,0.01m2 to accuracy of 1 
% or better.  
 
D.2.3 Metal plate , that is 5 mm smaller than the cutter and that has a thickness of 10 mm  
 
D.2.4 Balance , that is capable of determining the mass of the specimen to accuracy of 0.2 % or, in 
the case of 0.01m2 specimens, to an accuracy of 0.001g.  
 
D.3 General   
 
Condition the sample in accordance to ISO 139.  
 
D.4 Procedure 1 - Full width specimen  
 
D.4.1 Ensure that the fabric, which should preferably be selected from the middle of a piece, is not 
less than 0.5 m and not more than 4 m long, and lay it flat, and without tension, on the table. 
  
D.4.2 Cut at both ends across the full width of the sample along parallel lines at right angles to the 
selvedge.  
 
D.4.3 If the mass per unit area of a selvedge on a full –width piece appears to deviate appreciably 
from the mass per area of the body of the fabric, or if so agree upon between the parties concerned, 
trim off the selvedge along the outermost threads of the body of the fabric and use only the body of 
the fabric for the determination of the mass per unit area.  
 
D.4.4 Measure the width and length of the specimen.  
 
D.5 Procure 2 - For representative for large cuttings  
 
D.5.1 Ensure that available cutting is representative of the sample.  
 
D.5.2 Trim the cutting into a square or rectangle specimen by cutting along parallel lines at right 
angles to the warp (length) direction and at right angles to the weft(width) direction.  
 
D.5.3 Measure the width and length of the specimen. 
  
D.5.4 Use the balance to determine the mass of the specimen  
 
D.6 Procedure 3 - For several small (0.01m2) specimens Draft standard for Technical Commitee Meeting   
  
NOTE 2:  On fabrics with large in woven designs, which involve local areas of appreciably different 
mass per unit area, the use of procedure 1 or procedure 2 is preferable.  
 
D.6.1 Cut at least three square pieces, of side length of approximately 150 mm, from areas of the 
fabric selected to represent the samples as fully as possible but not within 50 mm of the selvedge. 
  
D.6.2 Lay each piece flat, and without tension, on a suitable cutting surface. place the metal plate 
and cutter on each piece in turn and cut out a 0.01  m2 specimen from each piece, ensuring that no 
loss of threads occurs.  
 
D.6.3 Use the balance to determine the mass of the 0.01  m2 specimens, and calculate the mean 
mass.  
 
D.7 Calculation  
 
D.7.1 In the case of procedure 1 and procedure 2, calculate the mass per unit area M in grams per 
square metre, using the following formula: 
 
𝑀=𝑚×1,000,000
𝐿×𝑤 
 
where  
 
m is the mass of the specimen, in grams  
L is the length of the specimen, in millimetres; and  
w is the width of the specimen, in millimetres  
 
D.7.2 In the case of procedure 3, calculate the mass per unit area ( M in grams per square metre) by 
multiplying the mean mass (in grams) by 100. 
 
  Draft standard for Technical Commitee Meeting   
 Annex E  
(Normative)  
ADVICE TO USERS 
 
The durability of foam in a particular application and the comfort provided depends on the use of the 
correct grade of foam. The recommended grades of foam for each type of duty are given in Table 4. 
Foams of grade numbers lower than the lowest of the applicable numbers shown in Column 3 are 
not suitable, but those of higher grade numbers may be used if desired. 
 
 
TABLE 4- GRADE OF FOAM SUITABLE FOR VARIOUS TYPES OF DUTY 
 
1 2 3 
 
TYPE OF DUTY   
APPLICATION EXAMPLES  GRADE OF FOAM 
RECOMMENDED  
 
Light (L) 
 
  
Padding; scatter cushions; pillows 
Light duty mattresses 
Light duty mattress toppers   
Light duty grade  
 
 
Average (A) 
 
 
 
  
Backs and armrests for private and commercial 
vehicles 
Backs and armrests for domestic furniture 
Medium duty mattresses 
Medium duty mattress toppers  
 
 
Medium duty grade 
 
 
 
Severe (S) 
 
 
 
 
 
 
  
Backs and armrests for cinema and theatre 
furniture 
Backs and armrests for contract furniture 
Backs and armrests for public transport 
Seats for private and commercial vehicles 
Seats for domestic furniture  
Heavy duty mattresses 
Heavy duty mattress toppers  
Heavy duty grade  
 
 
 
 
 
 
 
 
Very 
Severe (V)  
Seats for public transport 
Seats for cinema and theatre furniture 
Seats for contract furniture   
Superior heavy duty 
grade