KS 2938:2021   
 
KENYA STANDARDS  
 
 
 
 
 
 
 
 
 
 
Furniture - Sofa Set (Couch or Settee) – Specification  
 
 
 
KENYABUREAU OF STANDARDS  (KEBS)  
 
 
 
 
 
 
 
PUBLIC REVIEW DRAFT, NOVEMBER 2020  
 
 
© KEBS 20 20          First  Edition 20 20 
 
 
 
 
 
 KS 2938:2021   
 
 
TECHNICAL COMMITTEE REPRESENTATION  
 
The follo wing organizations were represented on the technical committee.  
 
Alsud Engineering Ltd  
Directorate of Occupational Safety and Health Services (DOSHS)  
Galua Fabricators Ltd  
Kenya Industrial Research and Development Institute (KIRDI)  
Kenya National Federatio n of Jua Kali Association (KNFJKA)  
Mount Kenya Furnitures Ltd  
Shauri Moyo Furniture Association  
Rosewood Furniture  Manufacturers Ltd  
Kenya Bureau of Standards (KEBS) - Secretariat  
 
 
REVISION OF KENYA STANDARDS  
 
In order to keep abreast of progress in indus try, Kenya Standards shall be regularly reviewed. 
Suggestions for improvements to published standards, addressed to the Managing Director, Kenya 
Bureau of Standards  
are welcome.  
 
 
 
© Kenya Bureau of Standards, 20 20 
Copyright. Users are reminded that by vi rtue of section 6 of the Copyright Act, Cap. 130 of the laws of Kenya, 
copyright subsists in all Kenya Standards and except as provided under section 7 of this Act, no Kenya Standard 
produced by Kenya Bureau of Standards may be reproduced, stored in a retr ieval system in any form or transmitted 
by any means without prior permission in writing from the Managing Director.  
 
 
 KS 2938:2021   
 
 
 
 
 
 
 
 
 
 
 
 
Furniture - Sofa Set (Couch or Settee) – Specification  
 
 
 
 
KENYA BUREAU OF STANDARDS (KEBS)  
Head Office:  P.O. Box 54974, N airobi -00200, Tel.: (+254 020) 605490, 602350, Fax: (+254 020 ) 604031  
E-Mail: info@kebs.org,  Web:http://www.kebs.org   
 
Coast Region                                           Lake Region         Rift Valley Region  
P.O. Box 99376, Mombasa -80100  P.O. Box 2949,  Kisumu -40100        P.O. Box 2138, Nakuru -20100  
Tel.: (+254  041) 229563, 230939/40  Tel.: (+254 057) 23549, 22396        Tel.: (+254 051) 210553, 210555  
Fax: (+254  041) 229448  Fax: (+254 057) 21814  
 
 
 KS 2938:2021   
 
    
Foreword  
 
Kenya Bureau of Standards is a national standard  body (NSB). The work of preparing Kenya Standards is 
normally carried out through national technical committees. Each member body interested in a subject for 
which a technical committee has been established has the right to be represented on that committee. 
National organizations, governmental and non -governmental, in liaison with KEBS, also take part in the 
work.  
Kenya Standards are drafted in accordance with the rules given in the KS ISO/IEC  Directives, Part  2. 
The main task of technical committ ees is to prepare National Standards. Draft Kenya Standards adopted 
by the technical committees are circulated to the technical committee members for balloting. Publication 
as a Kenya Standard requires approval by at least 2/3 of the members casting a vote . 
A couch, also known as a sofa, settee, futon, or chesterfield (see history of the term below) is a piece of 
furniture for seating two or three people in the form of a bench, with armrests, which is partially or entirely 
upholstered, and often fitted with  springs and tailored cushions. Although a couch is used primarily for 
seating, it may be used for sleeping. In homes, couches are normally found in the family room, living 
room, den, or the lounge. They are sometimes also found in non -residential settings  such as hotels, 
lobbies of commercial offices, waiting rooms, and bars.  
Attention is drawn to the possibility that some of the elements of this document may be the subject of 
patent rights. KEBS shall not be held responsible for identifying any or all suc h patent rights.  
This Kenya Standard was prepared by Technical Committee KEBS/TC  167, Furniture . 
 
 
During the preparation of this standard, reference was made to the following documents:  
 
IS 3663: 1993: Dimensions of tables and Chairs for office purposes  
 
The assistance derived from these publications is hereby acknowledged.  
 
 
 
 
 KS 2938:2021   
Kenya Standard  
 
Sofa Set – Specification  
1 SCOPE  
This Kenya Standard prescribes the requirements and test methods for Sofa Sets  (also known as couch 
or settee) . 
2 NORMATIVE REFRENC E 
This Kenya Standard incorporates by dated or undated references, provisions from other publications. 
These normative references are cited at the appropriate places in the text and the publications are listed 
hereafter.  
 
For dated references, subsequent a mendments to or revisions of these publications apply to this Kenya 
Standard only when incorporated in it by amendment or revision. For undated references, the latest 
edition of the publication referred to applies.  
 
ISO 7617 -2:2003, Plastics -coated fabrics  for upholstery — Part 2: Specification for PVC -coated woven 
fabrics  
KS 1267 -2, Pillows for domestic use — specification , Part 2: Synthetic -fibre filled  
KS 376, Flexible polyurethane (polyether) foams - Specification - Part 1: Mattresses (Third Edition)  
ISO 17076 -1:2020 , Leather — Determination of abrasion resistance — Part 1: Taber® method  
ISO 17236:2002 , Leather — Physical and mechanical tests — Determination of extension set  
CD 030/SER/2020, Furniture — Code of Practice — Joints used in Wooden Furniture  
DEFINITION  
For the purposes of this standard, the following definitions shall apply:  
2.1 
couch  also known as a  sofa, settee  or chesterfield  
is a piece of  furniture  for seating one or mo re people in the form of a  bench , with or without  armrests , that 
is partially or entirely  upholstered , and often fitted with  springs  and tailored  cushions . Although a couch is 
used primarily for  seating , it may be used for  sleeping  
 
2.2 
frame  
is usually m ade of wood, but can also be made of steel, plastic or laminated boards and most often than 
not gives shape, determines strength and by extension, durability of the sofa or couch or settee.  
  
3 TYPES  
The types of couches shall be  the one-, or more seater, designed for seating one, or more  persons.  
Note  1: A sectional sofa, often just referred to as a "sectional", is formed from multiple sections (typically two, three, 
and four) and usually includes at least two pieces that join at an angle of 90 degrees or  slightly greater, used to wrap 
around walls or other furniture.  KS 2938:2021   
Note 2:  Other variants include the  divan , the  fainting couch  (backless or partial -backed) and the canapé (an 
ornamental three -seater). To conserve space, some sofas double as  beds  in the form of  sofa beds , daybeds , 
or futons . 
 
4 REQUIREMENTS  
4.1 MATERIALS  
4.1.1  General  
 
A couch shall consist of the frame, the padding and the covering  or upholstery .  
 
Note: This shall not be applicable to the bench.  
 
4.1.2  Frame  
The frame shall be  made of wood or steel, plastic or boards.  
The wood used under the upholstery  shall be made from dr y wood that is free of defects and shall 
meet the requirements in table 1 below.  
Frame performance shall be tested in accordance with Annex A.   
Table 1. Physical and mechanical properties of wooden sofa set frame  
Moisture 
content  
(%) Density  
 
(g/cm3)  Tension 
strength  
(N/mm2) Compression 
strength  
(N/mm2) Shear 
strength  
 
(N/mm2) Bending 
strength  
(N/mm2) 
7.5-10.5 0.58-0.65 10.9-130 16.5-80 5.5-10.5 32.8-130 
 
 
 
4.1.3  Show wood  
The show wood of the legs, arms and back shall be suitable meeting requirements in table 1.  
 
4.1.4  Padding  
Sofa padding shall be made from foam , fibers , down  feathers  or a combination thereof  meeting the 
requirements of KS  376.  
 
If fiber cushions are used, then they shall conform to the requirements of KS  1267 -2. 
 
4.1.5  Upholstery/coverings  
4.1.5.1  General  
Sofa coverings shall be  made out of soft leather, corduroy or linen fabric coverings  or specialist 
reticulated foam  (for outdoor sofas) .  
 
4.1.5.2  Reticulated foams  
Due to its highly advanced open cellular struc ture, the upholstery shall have water freely pass 
through it making it highly resistant to soaking  and shall conform to the requirements of KS ISO 8873 
Parts 1 and 2.  
 
4.1.5.3  PVC-Coated type (“PU leather” or “resin”)  
If the uphol stery is of the PVC -Coated  type (“ PU leather” or “rexin ”) then it shall meet the requirements of 
KS ISO 7617 Parts 1, 2 and 3.  
 KS 2938:2021   
4.1.5.4  Leather  
If leather upholstery, i t shall conform to the requirements of KS ISO 17076 Part 2 and KS ISO 17236.  
 
4.2 Dimension(s)  
 
The general dime nsions for a single sofa shall be as shown in figure 1 below.  
 
 
(a)                 (b) 
 
 
 
 
(c) 
Figure 1: Schematic diagram for (a) Single seat, (b) double or two -seater and (c) three -seater settee or couch 
or sofa set.  
4.3  Joinery  
The settee joints shall be grooved beech dowels  or tongue -and-groove joints  in accordance to principles 
of CD030/SER/2020 .  
Note. CD030/SER/2020 under development  KS 2938:2021   
4.4  Adhesives  
4.4.1 Polyvinyl acetate adhesive shall be used to reinforce the joints of the frame wherever necessary . 
Polyvinyl acetate adhesives are preferred because of their cold applicability, easy spread, rapid drying, 
scentlessnes and fireproof nature.  
4.4.2 The adhesive shall meet the requirements in table 2;  
SL Characteristics  Requirements  
1 Density  1.1 g/cm3 
2 Viscosity  160-200 cps  
3 pH 5.00 
4 Ash rate  3 % 
 
4.5 Suspension System  
4.5.1  General.  The suspension system determines the bounce in the cushions, and how they support 
your weight when you sit on them.    The differing degrees of pressure your body put s on the cushions 
causes the coils to respond, giving what is known as “ride”.  
4.5.2 8-Way hand -tied Springs System  
The Gold Standard shall be  the labo r-intensive, 8 -way hand -tied spring system . Each spring shall be  set 
into the deck webbing and attached, with various spring rates depending on what portion of the seat deck 
its located. They are then tied together (8 strings per piece) and knotted at each juncture  not looped.  
 
 
4.5.3 The sinuous spring – or S –  system  
Sinuous springs are “S” shaped and run from the front of the seat to the back. These springs are 
supported by additional wires that cross from side to side.  The S springs lack the localized response of a 
coil system but gives a firm ride that some people prefer, and it has less potential for s agging over time.  
 
5.  Labelling  
The following information shall indelibly and legibly marked on each sofa set (couch or settee) by the 
manufacturer;  
a) Country of origin  
b) Name and address of the manufacturer;  
c) Registered Trade Mark  
d) Suspension system.  
 
 
 
 KS 2938:2021   
Annex A  
(normative)  
Test for the performance of the frame  
 
A.1 Preparation of test samples  
Frame members shall be made to the specification shown in table A.1 below.  
 
Table A-1. Measurements of the members of sofa frames (mm)  
Member  Length  Width  Thickness  
Stump  532 70 18 
Back post  800 70 18 
Arm  602 70 18 
Side rail  564 70 18 
Side slat  564 70 18 
Front rail  550 70 18 
Back rail  550 70 18 
Top rail  550 70 18 
 
A.1.1 G rooved beech dowels shall be utilized  in the joints , and the diameter of the dowels  shall be 8 mm 
while the length of the dowels shall be  40 mm.  
A.1.2 Horizontal and vertical drill presses shall be utilized for the dowel holes. Dowel hole centers are 
drilled at a point 16 mm from the edges symmetrically, and to the center of the thickne ss of the members 
from the faces. The distance between centerlines of two dowels shall be 38 mm. The depth of the 
embedment of the dowels in the edge shall be 27 mm, and  the depth of the embedment of the dowels in 
the face to be 13 mm. In the other words, penetration of the dowels shall be 13 mm.  
 
A.1.3 Assembling procedure of the sofa frames shall be performed in two phases ; The side frames of the 
sofa to be constructed first (sub -assembly); afterwards, the side frames shall be  combined to the front, 
back,  and top rails and assembly of the whole sofa frames constituted.  
 
A1.4 In the gluing process, glue is spread over the dowels and intersection surfaces, approximately with 
150±10 g/m2. In the pressing process, the sofa frames  are maintained for 2 hours by  applying  pressure to 
the joints.  
 
A.1.5 All sofa frames shall be  stored in a chamber with the  conditions of temperature of 20 ± 2 °C and 
relative  humidity of 65 ±5 percent for two months.  
 
A1.6 Measurements of the gravities shall be  made with an  analytic weighing machine with a sensitivity of 
0.01. The  moisture content is finally calculat ed. 
 
A.2 Performance Tests  
A.2.1 Tests are carried out on a 30 kN capacity “Seidner Bending Machine”. Static loading rate 
is adjusted to 6 mm/min. Sofa frames are tested a ccording to the principles of KS ISO 7174 -1 
by applying both seat and backrest loads which the sofa can be imposed upon in service 
(Figure 2).  KS 2938:2021   
 
Figure 2. Applying the seat and backrest loads  
 
A.2.2  Seat load (Fy), a constant value of 85 kgf (833 N), is ap plied to the sofa, backrest loading (Fx) was 
continued from the coordinate points as shown in Figure 2 until a failure or full separation occur in the 
joints or members of sofa frame.  
A.3 Procedure  
Required physical and mechanical properties for  structura l analysis of the wood and wood composite  
materials used in the tests shall be  evaluated in accordance  with the procedur es described in ASTM D 
1037 standard . 
A.4 Results  
In the tests, the ultimate failure loads are recorded in Newton (N).