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Reference number

DRS 378-1: 2017

© RSB 2017

RWANDA STANDARD

DRS

378-1

First edition

2017-mm-dd

Flexible polyurethane foam for mattresses — Specification — Part 1: General requirements

DRS 378-1: 2017

©RSB 2017- All rights reserved ii

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 2017

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 RSB.

Requests for permission to reproduce this document should be addressed to:

Rwanda Standards Board

P.O Box 7099 Kigali-Rwanda

KK 15 Rd, 49

Tel. +250 252 586103/582945

Toll Free: 3250

E-mail: [email protected]

Website: www.rsb.gov.rw

mailto:[email protected]

http://www.rsb.gov.rw/

DRS 378-1: 2017

iii ©RSB 2017- All rights reserved

Contents Page

Foreword ............................................................................................................................................................. v

1 Scope ...................................................................................................................................................... 1

2 Normative references ............................................................................................................................ 1

3 Terms and definitions ........................................................................................................................... 1

4 Requirements ......................................................................................................................................... 3 4.1 General ................................................................................................................................................... 3 4.2 Class and grade ..................................................................................................................................... 3 4.3 Density and hardness factor ................................................................................................................ 3 4.4 Colour ..................................................................................................................................................... 3 4.5 Flammability ........................................................................................................................................... 4 4.6 Cell count ............................................................................................................................................... 4 4.7 Porosity .................................................................................................................................................. 4 4.8 Other physical properties ..................................................................................................................... 4

5 Packing and marking ............................................................................................................................ 1

6 Sampling ................................................................................................................................................ 2

7 Inspection and test methods ................................................................................................................ 3 7.1 Inspection ............................................................................................................................................... 3 7.2 Conditioning .......................................................................................................................................... 3 7.3 Preparation of test samples and test specimen ................................................................................. 3

Annex A (normative) Dimensions ..................................................................................................................... 4 A.1 General ................................................................................................................................................... 4 A.1 Apparatus ............................................................................................................................................... 4 A.2 Procedure ............................................................................................................................................... 4

Annex B (normative) Density ............................................................................................................................. 5 B.1 Apparatus ............................................................................................................................................... 5 B.2 Test specimen ........................................................................................................................................ 5 B.3 Procedure ............................................................................................................................................... 5 B.4 Calculation ............................................................................................................................................. 5

Annex C (normative) Compression set ............................................................................................................ 6 C.1 Apparatus ............................................................................................................................................... 6 C.2 Test specimens ...................................................................................................................................... 6 C.3 Procedure ............................................................................................................................................... 6 C.4 Calculation ............................................................................................................................................. 6

Annex D (normative) Hardness factor .............................................................................................................. 7 D.1 Apparatus ............................................................................................................................................... 7 D.2 Test specimen ........................................................................................................................................ 7 D.3 Procedure ............................................................................................................................................... 7 D.4 Calculation ............................................................................................................................................. 7

Annex E (normative) Tensile properties .......................................................................................................... 9

DRS 378-1: 2017

©RSB 2017- All rights reserved iv

E.1 Apparatus ...............................................................................................................................................9 E.2 Test specimens ......................................................................................................................................9 E.3 Procedure ...............................................................................................................................................9 E.4 Calculations ............................................................................................................................................9

Annex F (normative) Tear resistance ............................................................................................................. 11 F.1 Apparatus ............................................................................................................................................ 11 F.2 Test specimens ................................................................................................................................... 11 F.3 Procedure ............................................................................................................................................ 11 F.4 Calculation ........................................................................................................................................... 11

Annex G (normative) Flammability ................................................................................................................ 12 G.1 Apparatus ............................................................................................................................................ 12 G.2 Test specimens ................................................................................................................................... 12 G.3 Procedure ............................................................................................................................................ 12

Annex H (normative) Tensile properties after heat aging ........................................................................... 14

Annex J (normative) Tensile properties after humid aging ........................................................................ 15

Annex K (normative) Fatigue resistance ...................................................................................................... 16 K.1 Apparatus ............................................................................................................................................ 16 K.2 Test specimen ..................................................................................................................................... 16 K.3 Procedure ............................................................................................................................................ 16 K.4 Calculation ........................................................................................................................................... 16

Annex M (normative) Permanent resistance to solvents............................................................................ 17 M.4 Procedure ............................................................................................................................................ 17 M.5 Calculation and reporting .................................................................................................................. 18

Annex P (normative) Porosity ....................................................................................................................... 20

.

DRS 378-1: 2017

v ©RSB 2017- All rights reserved

Foreword

Rwanda Standards 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 378-1 was prepared by Technical Committee RSB/TC 024, Chemicals and Consumer Products

In the preparation of this standard, reference was made to the following standard :

1) EAS 7-1, Flexible polyurethane foam for mattresses — Specification — Part 1: General requirements

The assistance derived from the above source is hereby acknowledged with thanks.

DRS 378 consists of the following parts, under the general title Flexible polyurethane foam for mattresses — Specification:

DRS 378-1 Flexible polyurethane foam for mattresses — Specification — Part 1: General requirements

DRS 378-2 Flexible polyurethane foam for mattresses — Specification — Part 2: Mattresses

DRS 378-3, Flexible polyurethane foam for mattresses — Specification — Part 3: Reconstituted flexible polyurethane foam

Committee membership

The following organizations were represented on the Technical Committee on Chemicals and Consumer Products (RSB/TC 024) in the preparation of this standard.

Paragraph of participants

Rwanda Standards Board(RSB) – Secretariat

DRS 378-1: 2017

1 ©RSB 2017- All rights reserved

Flexible polyurethane foam for mattresses — Specification — Part 1: General requirements

1 Scope

This Part 1 of this draft Rwanda Standard covers the requirements for eight classes (based on density) of flexible polyurethane foams of the polyether type, in the form of blocks, slabs, sheets, and shapes cut from these. Each class is sub-divided, according to the hardness of the foam, into at least four grades.

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.

DRS 378-2, Flexible polyurethane foam for mattresses — Specification — Part 1: Mattresses

DRS 378-3, Flexible polyurethane foam for mattresses — Specification — Part 3: Reconstituted flexible polyurethane foam

REAS 158, Gasoline (petrol) unleaded — Specification

3 Terms and definitions

For the purposes of this standard, the following terms and definitions apply

3.1

block

mass of polyurethane foam formed by a free-rising foam process, in its original form prior to conversion

3.2

defective

foam that fails in one or more respects to comply with the relevant requirements of the specification

3.3

polyurethane foam

foam in which the polyol component is a polyether. It is a cellular material produced by the reaction of the polyol with an organic isocyanate 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. Industrial synonyms are “log”, “bun”, “loaf”, “slab stock”

©RSB 2017- All rights reserved 2

3.4

lot

not less than 1 m3 and not more than 100 m3 of foam of the same class, grade, and nominal dimensions, from one manufacturer, submitted at any one time for inspection and testing

3.5

linear dimension

linear measurements of a specimen in different directions expressed in millimetres

3.6

density

the mass per unit volume of the foam specimen at 23 2 °C expressed in kg/m3

3.7

tensile strength

the stress at the breaking point of a specimen expressed in kgf/cm2

3.8

tensile stress

the stress at predetermined elongation of a specimen expressed in kgf/cm2

3.9

ultimate elongation (elongation at break)

percentage strain produced in a specimen stretched to its breaking point

3.10

hardness number

it is stated in the form of grading and is numerically equal to the compressive stress which is necessary to penetrate the specimen without puncture to a specified depth or deflection expressed as the load (kgf) per unit area of compression (cm2). Hardness number at 40 % or 50 % deflection on specific thickness of sample is also referred to as hardness index

3.11

indentation hardness index

load required to produce a depression of 40 % of initial thickness of the sample

DRS 378-1: 2017


3.12

load quotient (indentation hardness characteristic)

ratio of hardness number at two specified deflections, namely, 65 % and 25 %

4 Requirements

4.1 General

Foam shall be polyether foam, shall be non-toxic, and shall be free from objectionable odour. The cell structure shall be such that it is acceptable and in the cases of trimmed blocks, slabs, sheets, and shapes cut from any of these, the surfaces shall be smooth and free from cuts, tears, and skins.

4.2 Class and grade

The class and the grade of foam shall be one of the combinations given in Table 1.

Table 1 — Classes and grades of foam

Class

No

Grade

No

Grade

No

Grade

No

Grade

No

Grade

No

Grade

No

1 2 3 4 5 6 7

17 6 9 12 16 - -

20 6 9 12 16 - 24

23 6 9 12 16 20 24

26 6 9 12 16 20 24

30 6 9 12 16 20 24

36 - 9 12 16 20 24

44 - 9 12 16 20 24

48 - - 12 16 20 24

4.3 Density and hardness factor

The density of foam, determined in accordance with Annex B, and its hardness factor, determined in accordance with Annex D, shall be within the appropriate limits given in Table 2.

4.4 Colour

The colours of foam shall be as follows:

a) Light duty — White or blue


b) Medium duty — Grey

c) Heavy duty — Red, pink or violet

d) Super heavy duty — Green

4.5 Flammability

When foam is tested in accordance with Annex G,

a) no specimen shall burn for 3 min or more; and

b) no specimen shall burn beyond the gauge line.

4.6 Cell count

The number of cells % per centimetre of foam, determined in accordance with Annex M shall not exceed the limit specified by the purchaser.

4.7 Porosity

When the porosity of foam is specified by the purchaser, the foam, when tested in accordance with Annex N, shall permit the flow of air at the rate so specified.

4.8 Other physical properties

When tested in accordance with the relevant methods given in the Annexes, foam shall comply with the requirements given in Table 3 appropriate to the class and grade of the foam.

Table 2 — Density and hardness factor

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Class

Density,

kg/m3

Grade

6 9 12 16 20 24

Hardness factor

Min. Max. Min

. Max. Min. Max. Min. Max. Min. Max. Min. Max. Min. Max.

DRS 378-1: 2017


17

20

23

26

30

36

44

48

15

17.6

21.1

24.1

27.1

32.1

40.1

48.1

17.5

21.0

24.0

27.0

32.0

40.0

48.0

-

3.6

3.6

3.6

3.6

3.6

-

-

-

7.2

7.2

7.2

7.2

7.2

-

-

-

7.2

7.2

7.2

7.2

7.2

7.2

7.2

-

10.8

10.8

10.8

10.8

10.8

10.8

10.8

-

10.8

10.8

10.8

10.8

10.8

10.8

10.8

10.8

14.4

14.4

14.4

14.4

14.4

14.4

14.4

14.4

14.4

14.4

14.4

14.4

14.4

14.4

14.4

14.4

18.0

18.0

18.0

18.0

18.0

18.0

18.0

18.0

-

-

18.0

18.0

18.0

18.0

18.0

18.0

-

-

21.6

21.6

21.6

21.6

21.6

21.6

-

-

21.6

21.6

21.6

21.6

21.6

21.6

-

-

25.2

25.2

25.2

25.2

25.2

25.2

DRS 378-1: 2017


Table 3 — Other physical properties

1 2 3 4 5 6 7 8 9 10 11

Property

Class

17 20 23

Grade

6 9 12 16 6 9 12 16 6 9

Compression set, %, max.

Tensile properties

Tensile strength

Original, kPa, min.

ii) After heat aging, retention of original, %,

min.

After humid aging, retention of original, %, min.

b) Elongation at break

Original, %, min.

After heat aging, retention of original, %, min.


Tear resistance, N/mm of width, min.

Permanent resistance to solvents

Visible deterioration (all solvents)

Swelling, %

Tensile strength, retention of original, %, min.

Fatigue resistance

15

59

80

80

100

40

40

0.175

90

15

69

80

80

100

40

40

0.219

90

15

69

80

80

100

40

40

0.219

90

15

69

80

0

100

40

40

0.219

90

12

69

80

80

100

40

40

0.219

Nil

Nil

90

12

69

80

80

100

40

40

0.263

90

12

69

80

80

100

40

40

0.263

90

12

69

80

80

100

40

40

0.263

90

10

69

80

80

100

40

40

0.263

90

10

83

80

80

100

40

40

0.350

90


Retention of hardness factor, %, min.

Loss in height, %, max.

60

5

60

5

60

5

60

5

60

5

60

5

60

5

60

5

70

4

70

4

NOTE A change in colour shall not be construed as evidence of deterioration.

Table 3 (continued)

1 2 3 4 5 6 7 8 9 10 11

Property

Class

23 26

Grade

12 16 20 24 6 9 12 16 20 24


Tensile properties

Tensile strength

Original, kPa, min.


iii) After humid aging, retention of original, %, min.

Elongation at break

Original, %, min.




10

83

80

80

100

40

40

10

83

80

80

100

40

40

10

83

80

80

100

40

40

10

83

80

80

100

40

40

9

69

80

80

100

40

40

9

83

80

80

100

40

40

9

83

80

80

100

40

40

9

83

80

80

100

40

40

9

83

80

80

100

40

40

9

83

80

80

100

40

40

DRS 378-1: 2017



Visible deterioration (all solvents)

ii) Swelling, %

iii) Tensile strength, retention of original, %, min.

Fatigue resistance

i) Retention of hardness factor, %, min.

ii) Loss in height, %, max.

0.350

90

70

4

0.50

90

70

4

0.350

90

70

4

0.350

90

70

4

0.263

Nil

Nil

90

75

3

0.350

90

75

3

0.350

90

75

3

0.350

90

75

3

0.350

90

75

3

0.350

90

75

3


Table 3 (continued)

1 2 3 4 5 6 7 8 9 10 11 12

Property

Class

30 36

Grade

6 9 12 16 20 24 9 12 16 20 24

DRS 378-1: 2017



Tensile properties

Tensile strength

Original, kPa, min.

ii) After heat aging, retention of original, %, min.


Elongation at break

Original, %, min.





i) Visible deterioration (all solvents)

ii) Swelling, %


Fatigue resistance



8

69

80

80

100

40

40

0.263

90

77.5

2.5

8

83

80

80

100

40

40

0.350

90

77.5

2.5

8

83

80

80

100

40

40

0.350

90

77.5

2.5

8

83

80

80

100

40

40

0.350

90

77.5

2.5

8

97

80

80

100

40

40

0.350

Nil

Nil

90

77.5

2.5

8

97

80

80

100

40

40

0.350

90

6

69

80

80

100

40

40

0.350

90

80

2

6

69

80

80

100

40

40

0.350

90

80

2

6

83

80

80

100

40

40

0.350

90

80

2

6

97

80

80

100

40

40

0.350

90

80

2

6

97

80

80

100

40

40

0.350

90

80

2


Table 3 (continued)

1 2 3 4 5 6 7 8 9 10

Property

Class

44 48

Grade

9 12 16 20 24 12 16 20 24

DRS 378-1: 2017



Tensile properties

Tensile strength

i) Original, kPa, min.



Elongation at break

i) Original, %, min.





i) Visible deterioration (all solvents)

ii) Swelling, %


Fatigue resistance



5

69

80

80

100

40

40

0.263

90

82.5

2

5

69

80

80

100

40

40

0.263

90

82.5

2

5

83

80

80

100

40

40

0.350

90

82.5

2

5

97

80

80

100

40

40

0.350

Nil

Nil

90

82.5

2

5

97

80

80

100

40

40

0.350

90

82.5

2

4

83

80

80

100

40

40

0.263

90

85

1.5

4

97

80

80

100

40

40

0.350

90

85

1.5

4

118

80

80

100

40

40

0.350

90

85

1.5

4

118

80

80

100

40

40

0.350

90

85

1.5

DRS 378-1: 2017


4.9 Shape and dimensions

The foam shall be supplied in the form of blocks, trimmed blocks, slabs or sheets cut from trimmed blocks, or other shapes cut from any of these forms, and the actual dimensions, measured in accordance with 7.3 shall not differ from the nominal values by more than the appropriate tolerances given in Table 4.

Table 4 — Tolerances on dimensions (other than of blocks)

Length and width Thickness

D 25

25 < D 150

151 < D 300

301 < D 600

601 < D 1 000

1 000 <D 1 500

1 501< D 2 000

D > 2 000

- 5 % + 10 %

- 0 + 6.5

- 0 + 6.5

- 0 + 12.5

- 0 + 20

- 0 + 30

- 0 + 40

- 0 + 45

- 5 % + 10 %

- 0 + 4.8

- 0 + 6.5

- 0 + 12.5

- 0 + 20

- 0 + 30

- 0 + 420

- 0 + 45

5 Packing and marking

5.1 Packing

The foam shall be so packed that it is protected from dirt, gross distortion, and nicking during normal transport and storage.

5.2 Marking

The following information shall appear in legible and durable marking on the outside of each package on each piece of foam:

a) name and address of manufacturer;


b) lot or batch number;

c) dimensions;

d) class and grade of foam;

e) made in Kenya/country of origin.

6 Sampling

6.1 The following sampling procedure shall be applied in determining whether a lot complies with the requirements of the specification. The samples so taken shall be deemed to represent the lot.

Take at random from the lot the number of samples shown in Column 2 of Table 5 relative to the appropriate lot size shown in Column 1. Each sample shall consist of the following:

a) For inspection ― A complete piece.

b) For testing ― Pieces of total volume at least 0.01 m3.

Table 5 — Sampling

Size of lot, L, m3 Number of samples

1 2

L 8 2

8 < L l5 3

15 < L 25 5

25 < L 50 8

50 < L l00 13

6.2 Compliance with the specification

The lot shall be deemed to comply with the specification if after inspection and testing of the samples taken in accordance with Clause 6, no defective is found.

DRS 378-1: 2017


7 Inspection and test methods

7.1 Inspection

Visually examine and measure (using the method given in Annex A) the samples (see 6.1 (a)) for

compliance with the requirements of 6.1, 4.8, 4.9, and Clause 5.

7.2 Conditioning

Before testing, maintain all specimens for at least 16 h in an atmosphere having a relative humidity of wise

65 ± 2 % and a temperature of 23 ± 2 °C.

7.3 Preparation of test samples and test specimen

7.3.1 From each sample obtain, as follows, a test sample for each test given in the Annexes.

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, 50 mm.

7.3.2 When cutting the test specimens (Annexes B, C and M), 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.


Annex A (normative)

Dimensions

A.1 General

A.1 Apparatus

A.1.1 Metre rule, a steel rule graduated in millimetres and accurate to 1 mm (or better).

A.1.2 Micrometer, a micrometer accurate to 0.01 mm (or better) with a presser foot of area at least 6.5 cm and capable of exerting a pressure of 100 + 10 Pa.

A.2 Procedure

Measure the dimensions of each sample (using the rule for dimensions greater than 30 mm and the micrometer for dimensions not exceeding 30 mm).

DRS 378-1: 2017


Annex B (normative)

Density

B.1 Apparatus

B.1.1 Balance, a balance having a sensitivity of 0.1 g (or better).

B.1.2 Measurement, as in A.1.

B.2 Test specimen

The test specimen may be of any size or shape provided that its volume is at least 500 cm3 and can easily be calculated from its linear dimensions, and that the specimen is cut from the full thickness of the sample.

B.3 Procedure

a) Determine the mass of the specimen.

b) Measure the dimensions of the specimen by the method described in Annex A and calculate its volume.

B.4 Calculation

Calculate the density of the specimen as follows:

001

vD

M

where,

D density, in kg/m3;

M mass, in g;

V volume, in cm3.


Annex C (normative)

Compression set

C.1 Apparatus

C.1.1 Jig, a compression set jig consisting of two rigid steel plates each of size at least 100 mm x 60 mm, held parallel to each other by means of bolts and held 6.25 mm apart by means of metal spacers.

C1.2 Oven, an air-circulating oven maintained at 70 °C.

C.2 Test specimens

From the appropriate slab (see 6.1 (b) cut three rectangular test specimens 50 mm x 50 mm x 25 mm.

C.3 Procedure

Measure as in Annex A the thickness of each specimen. Place a specimen in the jig, compress it from 25 mm to a thickness of 6.25 mm and, within 15 min, place the assembly in the oven for 22 h. Remove the assembly from the oven, remove the specimen from the compression set device, allow the specimen to recover for a period of 35 ± 5 min, and then measure the thickness. Repeat the test on the remaining specimens.

C.4 Calculation

Calculate the compression set of each specimen as follows:

Compression set, % =

100

o

co

t

tt

where,

to = the original thickness of test specimen, in mm;

tc = the final thickness of test specimen, in mm.

Record the mean of the three results as the compression set of the sample.

DRS 378-1: 2017


Annex D (normative)

Hardness factor

D.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 cm2, and that can be raised or lowered at a speed of 100 ± 20 mm 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.

D.2 Test specimen

From the appropriate slab (see 6.1(b)) 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 mav be plied together (without the use of an adhesive) to give a total thickness of 50 mm.

D.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 (TL):

TL = A ― B

where,

TL thickness of specimen, under load, in millimeters (mm)

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 % of its calculated thickness and note the force recorded on the gauge after 60 s.

D.4 Calculation

Calculate, as follows, the hardness factor HF of the specimen, and record this value as the hardness factor of the sample:


HF = 0.102 × F

where

HF is the force, in newtons required to produce 40 % compression.

Report the value as the hardness factor.

DRS 378-1: 2017


Annex E (normative)

Tensile properties

E.1 Apparatus

E.1.1 Tensile-strength testing machine, a tensile-strength testing machine of the self-aligning type, and of size and design suitable for breaking the test specimens under a tensile load. The speed of the moving beam shall be 500 ± 50 mm/min. The machine shall be equipped with an indicator that records the maximum force applied during the test and with jaws that so clamp the specimens that they will not slip during testing.

E.1.2 Micrometer, accurate to 0.01 mm (or better) with a presser foot of area at least 6.5 cm2 and capable of exerting a pressure of 100 Pa ± 10 Pa.

E.1.3 Die, a steel die of the shape and dimensions given in, Figure E.1.

E.1.4 Steel rule, graduated in millimetres and accurate to 1 mm (or better).

E.2 Test specimens

From the appropriate slab (see 6.1(b)) cut using the dies five specimens each of thickness of at least 12.5 mm, and mark the gauge length (see Figure E.1) on each specimen.

E.3 Procedure

Accurately measure the thickness and the width of a test specimen at three points equally spaced along the gauge length. Then so clamp the ends of the specimen in the jaws of the machine that the distance between the jaws is 90 ± 5 mm, operate the machine until the specimen ruptures and record the maximum force applied and the distance between the reference lines at rupture. Repeat the test on the remaining four test specimens.

E.4 Calculations

E.4.1 Calculate the average cross-sectional area of the narrow section of each test specimen, and then calculate its tensile strength TS as follows:

TS = 1000 × A

F max

Where

TS is the tensile strength, in kilopascals (kPa);


Fmax is the maximum force applied, in newtons (N);

A is the average cross-sectional area, in millimetres cubed (mm2).

Record the average of the five results as the tensile strength of the sample.

E.4.2 Calculate the elongation at break of each test specimen as follows:

100

b

o

o

L

LLE

where,

Eb is elongation at break, in percentage (%);

L is the distance between the reference lines at rupture, in millimetres (mm);

Lo is the original distance between the reference lines, in millimetres (mm).

Record as the elongation at break of the sample the mean of the five results.

Figure E.1 — Steel die

DRS 378-1: 2017


Annex F (normative)

Tear resistance

F.1 Apparatus

F.1.1 Tensile-strength testing machine, of the self-aligning type, and of size and design suitable for breaking the test specimens under a tensile load. The speed of the moving beam shall be (50 ± 50) mm/min. The machine shall be equipped with an indicator that records the maximum force applied during the test and with jaws that so clamp the specimens that they will not slip during testing.

F.1.2 Micrometer, accurate to 0.01 mm (or better) with a presser foot of area at least 6.5 cm2 and capable of exerting a pressure of 100 Pa ± 10 Pa.

F.2 Test specimens

From the appropriate slab (see 6.1(b)) cut five specimens each of size 150 mm × 25 mm × 25 mm. By cutting longitudinally as in Figure F.1 down the centre of each specimen, form two tongues of length 40 mm.

F.3 Procedure

Using the micrometer, measure the width of the specimen, and then clamp the tongues in the jaws of the machine. Operate the machine, ensuring that the tear propagates through the centre of the specimen (by nicking with a razor blade, if necessary), until the specimen is torn for a distance of at least 50 mm, and note the maximum force recorded during the test. Repeat the test on the other four specimens.

F.4 Calculation

Calculate the tear resistance of each specimen TR as follows:

TR = W

Fmax

where

TR is the tear resistance, in newtons per millimetre of width (N/mm);

Fmax is the maximum force applied, in newtons (N);

W is the width of the specimen, in millimetres (mm).

Report the mean tear resistance of the five specimens as the tear resistance of the sample.


Annex G (normative)

Flammability

G.1 Apparatus

An apparatus as shown schematically in Figure G.1 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 % or better.

G.2 Test specimens

From the appropriate slab (see 6.1(b)) cut five specimens each of size 12.5 ± 0.5 mm × 12.5 ± 0.5 mm × 130 mm and draw a gauge line across each specimen 75 mm from the end that is to be positioned uppermost in the apparatus.

G.3 Procedure

Clamp a test specimen in the holder of the apparatus so that it is held vertically in the centre 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 % 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.

DRS 378-1: 2017


Figure G.1 — General arrangement of flammability test apparatus


Annex H (normative)

Tensile properties after heat aging

Determine as in Annex F the tensile strength and elongation at break of five specimens that have been heat aged for 22 h in an air oven at 140 ºC ± 1 ºC.

Calculate the resistance to heat aging Aheat of the sample as follows:

Aheat = ts

ts 100aged

where

Aheat is the resistance to heat aging, expressed as a ratio of tensile strengths, as a percentage (%);

tsaged is the tensile strength of the heat aged sample, in kilopascals (kPa);

ts is the original tensile strength, in kilopascals (kPa).

DRS 378-1: 2017


Annex I (normative)

Tensile properties after humid

aging

Determine as in Annex F the tensile strength and elongation at break of five specimens that have been humid aged in dry steam at 105 ºC ± 1 ºC for 3 h, dried at 70 ºC to constant mass, and conditioned as in 7.2.

Calculate the resistance to humid aging of the sample as follows:

ts

tsA

100aged

humid

Ahumid is the resistance to humid aging, expressed as a ratio of tensile strengths, as a percentage (%);

tsaged is the tensile strength of the humid aged sample, in kilopascals (kPa);

ts is the original tensile strength, in kilopascals (kPa).


Annex J (normative)

Fatigue resistance

K.1 Apparatus

K.1.1 Flexing machine, that consists of two rigid parallel plates, 50 mm apart, the upper plate being capable of so oscillating through a distance of 37.5 mm at a frequency of one cycle per second as to compress the specimen to 25 % of its unstressed thickness. The bottom plate has 6 mm diameter perforations at 20 mm centres and the size of each plate shall be at least 400 mm × 400 mm.

K.1.2 Steel rule, graduated in millimetres and accurate to 1 mm (or better).

K.2 Test specimen

From the appropriate slab (see 6.1(b)), cut one rectangular specimen of size 380 mm × 380 mm × 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.

K.3 Procedure

Determine the hardness factor as in D.4, then place the specimen between the plates of the flexing machine and subject it to 100 000 flexing cycles. Remove the specimen, allow it to recover for 30 min, measure the height of the specimen, and then redetermine its hardness factor.

K.4 Calculation

Calculate the retention of hardness factor Aflex of the sample as follows:

100f lex

f lex

hf

hfA

where

Aflex is the retention of hardness factor, in percentage (%);

hfflex is the hardness factor after flexing;

hf is the hardness factor before flexing.

Calculate also the percentage loss in height of the specimen

DRS 378-1: 2017


Annex K (normative)


M.1 Apparatus

M.1.1 Glass container, large enough to allow complete immersion, of a test specimen, without bending.

M.1.2 Flat wire gauze scoop

M.1.3 Wire gauze sinker

M.1.4 Square of plate glass

M.1.5 Measuring equipment, as in A.1.

M.2 Reagents

M.2.1 Petrol, complying with the requirements of EAS 158.

M.2.2 Light naphtha

M.2.3 Denatured alcohol

M.2.4 Trichloroethylene

M.3 Test specimen

From the appropriate slab (see 6.1(b)), cut four specimens each of size at least 150 mm × 150 mm and of thickness approximately 10 mm.

M.4 Procedure

Measure, as in A.2, the thickness, length, and width of a specimen, and immerse it in one of the reagents in the container ensuring that it is totally submerged by covering it with the wire gauze sinker. After 30 min, remove the sinker and, using the scoop, remove the specimen, and allow it to drain in the scoop for 5 min. Then carefully transfer the specimen on to the glass plate, ensuring that the specimen is not distorted in any way during the transfer.

Condition the assembly as in 7.2, but for at least 48 h or such longer period as may be necessary to ensure complete removal of the reagent. Remeasure the length, width, and thickness of the specimen and, disregarding any change in colour, inspect the specimen for signs of visible deterioration. Then determine its tensile strength as in Annex F.


Repeat the test with the other reagents, using a different specimen in each test.

NOTE To avoid damage to the specimen, its thickness after immersion should be determined by measuring the total thickness of the

assembly and deducting the thickness of the glass plate.

M.5 Calculation and reporting

For each reagent, calculate the swelling S of the sample as follows:

10011

1122

ta

tataS

where

S is the swelling, as a percentage (%);

a1 is the original area, in square millimetres (mm2);

a2 is the area after immersion, in square millimetres (mm2);

t1 is the original thickness, in millimetres (mm);

t2 is the thickness after immersion, in millimetres (mm).

DRS 378-1: 2017


Annex L (normative)

Cell count

N.1 Apparatus

A thread counter consisting of a lens of 5 times magnifying power mounted over a base plate that contains a rectangular aperture of accurately known length. The mass of the thread counter must be sufficiently low (or the thread counter must be so supported) as not to deform the specimen.

N.2 Test specimens

From each sample cut (see 6.1(b)) three specimens each of size 100 mm × 100 mm.

N.3 Procedure

Place the thread counter on the test specimen, count the number of cells intersected by one of the edges of the aperture, and calculate the number of cells per lineal centimetre. Repeat the test on the remaining two specimens and record the average of the three values obtained as the cell count of the sample.


Annex M (normative)

Porosity

P.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 centre 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.

P.2 Test specimens

From the appropriate slab (see 6.1(b)) cut four cylindrical specimens each of diameter 38 mm and height 25 mm.

P.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 = 2 040 F

where,

F = the flow rate, in m3 / s.

Record the mean of the four results as the porosity of the sample.

DRS 378-1: 2017


Annex N (normative)

Advice to users

The durability of a foam in a particular application and the comfort provided, depends on the use of the correct class of foam. The recommended class(es) of foam for each type of duty are given in Table P.1. Foams of class numbers lower than the lowest of the applicable numbers shown in Column 3 are not suitable, but those of higher class numbers may be used if desired.

Table R.1 — Classes of foam suitable for various types of duty

1 2 3

Type of duty

Application examples

Class of foam

recommended

Light (L)

Medium

Heavy

Very

Heavy

Padding; scatter cushions; pillows

Light duty mattresses

Light duty mattress toppers

Backs and armrests for private and commercial

vehicles

Backs and armrests for domestic furniture

Medium duty mattresses

Medium duty mattress toppers

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

Seats for public transport

Seats for cinema and theatre furniture

Seats for contract furniture

17; 20

23; 26

30

36; 44; 48

DRS 378-1: 2017


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