ICS  77.140.75  
 
Reference number  
DRS 263 -4: 2020  
© RSB 2020  
  
 RWANDA STANDARD  DRS  
263-4 
 
Second edition  
2020 -06-dd 
 
Steel tubes for non -pressure purposes — 
Specification  
Part 4: Stainless Steel tubes for round, 
oval, square and rectangular section for 
furniture  
   
DRS 263 -4: 2020  
©RSB 2020 - 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 2020  
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 R SB. 
Requests for permission to reprodu ce this document should be addressed to : 
Rwanda Standards  Board  
P.O Box 7099 Kigali -Rwanda  
KK 15 Rd, 49  
Tel. +250 788303492  
Toll Free: 3250  
E-mail: info@rsb.gov.rw  
Website: www.rsb.gov.rw  
ePortal: www.portal.rsb.gov.rw   DRS  263-4: 2020  
iii                ©RSB 2020 - All rights reserved  
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ...................  iv 
1 Scope  ................................ ................................ ................................ ................................ .............  1 
2 Normative references  ................................ ................................ ................................ ...................  1 
3 Terms and definitions  ................................ ................................ ................................ ..................  1 
4 Requirements  ................................ ................................ ................................ ................................  1 
4.1 Material  ................................ ................................ ................................ ................................ ..........  1 
4.2 Type, grade, supply condition and physical properties of tubes  ................................ ............  2 
4.3 Nominal size of tube, wall thickness and tolerances  ................................ ...............................  2 
4.4 Length  ................................ ................................ ................................ ................................ ............  3 
4.5 Straightness  ................................ ................................ ................................ ................................ .. 3 
4.6 Tubes of squar e and rectangular section  ................................ ................................ ..................  3 
4.7 Freedom from defects and finish  ................................ ...................  Error! Bookmark not defined.  
4.8 Cross -welds  ................................ ................................ ................................ ................................ .. 4 
5 Packing and marking  ................................ ................................ ................................ ...................  5 
5.1 Packing  ................................ ................................ ................................ ................................ ..........  5 
5.2 Marking  ................................ ................................ ................................ ................................ ..........  5 
6 Sampling  ................................ ................................ ................................ ................................ ....... 5 
7 Criteria of compliance  ................................ ................................ ..... Error! Bookmark not defined.  
8 Inspection and methods of test  ................................ ................................ ................................ .. 5 
8.1 Inspection  ................................ ................................ ................................ ................................ ...... 5 
8.2 Tensile tests  ................................ ................................ ................................ ................................ .. 6 
8.3 Flattening test (round section)  ................................ ................................ ................................ .... 6 
8.4 Drift expansion test (round section)  ................................ ................................ ...........................  6 
 DRS 263 -4: 2020  
©RSB 2020 - All rights reserved                  iv 
 Foreword   
Rwanda Standard s are prepared  by Technical Committees and approved by R wanda 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 Rwand a Standards adopted 
by Technical committ ees are ratified  by me mbers of RSB Board of Director s for publication and gazettment as 
Rwanda Standards.  
DRS  263-4 was prepared by Technical Committee RSB/TC 47, Steel aluminium and related products  
In the preparation of this standard, reference was made to the following standard:  
1)  SANS 657 -4: 2010 Steel tubes for non -pressure purposes — Part 4: Steel tubes of round, oval, square and 
rectangular section for furniture  
The assistance de rived from the above sou rce is hereby acknowledged with thanks.  
This second  edition cancels and replaces the first  edition (RS  263-4: 2015 ), which has been technically revised.  
DRS 263 consists of the following parts, under the general title Steel tubes for non -pressure purposes — 
Specification :  
 Part 1: Sections for scaffolding general engineering and structural applications  
 Part 2: Steel tubes for cycles  
 Part 3: Steel tu bes for rolls for conveyor belt idles  
 Part 4: Steel tubes for rolls for round, oval, square and rectangular  section for furniture.  
Committee membership  
The following organizations were represented on the Technical Committee on Steel aluminium and related 
products  (RSB/TC 47) in the preparation of this standard.  
University of Rwanda - College of Science and Techn ology (UR -CST)  
MANUMETAL  
Rwanda Transport Development Agency (RTDA)  
HEROCEAN Ltd  
AFRIFOAM  DRS  263-4: 2020  
v                ©RSB 2020 - All rights reserved  
 IPRC Ngoma  
Mota Engil  
Ministry of infrastructure (MININFRA)  
National quality testing laboratory (NQTLD)  
Rwanda  Standards Board  (RSB) – Secretariat  DRS 263 -4: 2020  
1                ©RSB 2020 - All rights reserved  
 Steel tubes for non -pressure purposes — Specification — Part 3: 
stainless Steel tubes for round, oval, square and rectangular section for 
furniture  
1 Scope   
This Draft Rwanda Standard specifies requirements , sampling  and test methods of round, oval, square and 
rectangular section  stainless steel  for use to manufacture  furniture .  
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 reference d document (including any amendments) applies.  
RS ISO 6892 -1, Metallic materials – Tensile testing – Part 1: Method of test at room temperature  
3 Terms and definitions  
For the purposes of this standard , the follow ing terms and definitions apply  
3.1  
Acceptab le Quality Level (AQL)  
acceptable to the authority administering this standard, or to the parties concluding the purchase contract, as 
relevant   
3.2  
defective  
tube that fails in one or more respects to comply with the relevant requirement of this part o f the specification  
3.3  
lot  
not less than 50 and not more than 10 000 steel tubes of the same material, type, grade, finish, nominal length, 
size and wall thickness, from one manufacturer, submitted at any one time for inspection and testing.  
4 Requirements  
4.1 Material  
Tubes shall be made of austenitic stainless steel for class A, type 1 or type 2 tubes.   
©RSB 2020 - All rights reserved                  2 
 4.2 Supply condition and mechanical properties of tubes  
4.2.1  supply condition and  when determined in accordance with Clause 7, the mechanical propert ies of a 
tube, shall be the appropriate of those given in Table 1.  
4.2.2  When tested in accordance with 6.3 and 6.4, a tube shall show no sign of cracking or any other such 
defect.  
Table 1 — Type, grade, supply condition and physical properties of tubes  
Type 
designation  Grade  Yield stress, 
MPa, min  Tensile 
strength, 
MPa, min  elongation %, 
min supply 
condition  
Class A 
Type 1  304  310 628 30 Direct off mill 
(DOM)  
Class A 
Type 2  304  186 538 45 Heat -treated, 
descaled and 
surface finished  
4.3 Nominal size of tube, wall thickness and tolerances  
4.3.1  The nominal size and wall thickness of the tubes shall be within the range provided in Table 2, Table 
3 and Table 4.  
Table 2 — Tubes of round section  
Nominal 
size mm  External diameter mm  Wall thickness mm  Approximate mass 
Kg/m  
Max.  Min. Nominal  Max.  Min. Nominal wall thickness 
mm 
1.2 1.6 
16 16.16  15.84  - Not limited  - 0.445  0.578  
20 20.20  19.80  - - 0.564  0.736  
25 25.25  24.75  1.2 1.14 0.704  0.936  
32 32.32  31.68  1.6 1.52 0.925  1.22 
50 50.50  49.50  - - 1.46 1.94 
Table 3 — Tubes of square section  
Nominal size 
mm External dimensions mm  wall thickness mm  Approximate 
mass Kg/m  Max.  Min. Nominal  Max.  Min. 
25 × 25  25.15  24.85  1.6 Not limited  1.52 1.242  
32 × 32  32.19  31.81  1.6 1.52 1.585  
 DRS 263 -4: 2020  
3                ©RSB 2020 - All rights reserved  
 Table 4 — Tubes of rectangular section  
Nominal 
size mm  External dimensions mm  wall thickness mm  Approximate mass 
g/mm  
d1 d2 Nominal  Max.  Min. Nominal wall 
thickness mm  
Max.  Min. Max.  Min. 1.2 1.6 
50 × 20  50.30  49.70  20.12  19.88  1.2 Not 
limited  1.14  1.256  1.634  
50 × 2 5  50.30  49.70  25.15  24.85  1.6 1.52  1.348  1.890  
NOTE 1  Approximate mass included in these tables is for information only.  
NOTE 2  Dimensions specified in these tables shall be measured:  
a) across the flats in the case of tubes of square or rectangular section; and  
b) across the smallest and largest dimensions in the case of tubes of oval section.  
4.4 Length  
Tubes shall be supplied in random lengths in the range 4 to 7 m or if so required in:  
a) specified cut lengths (subject to a tolerance of ± 1 mm. unless otherwise agreed upon); or  
b) specified "mill cut" lengths ( subject to a tolerance of 0 )   
4.5 Straightness  
Any deviation from straightness in a length of tube shall not exceed 1 in 1 000 measured at the midpoint of the 
length.  
4.6 Tubes of square and rectangular section  
When a tube of square or rectangular section is measured in accordance with 6.1:  
a) any twist in the length measured, at least 30 mm from the end of the tube, shall not exceed 2.5 mm pe r 
metre of the length (see figure 1);  
b) external dimensions resulting from any concavity/convexity of the outer surface shall not deviate from the 
nominal external dimensions by more than 1 %; and  
c) corner radius of the tube (see figure 1) shall not exceed 3 T where T is equal to the wall thickness. The 
nominal internal and external radii shall be 1.5T and 2.5T.   
©RSB 2020 - All rights reserved                  4 
  
Figure 1(a) — Square section  
NOTE  Twist to be measured at a distance of at least 30 mm from the end of the tube  
 
Figure 1(b) — Rectangular section  
Figure 1 — Measurement of twist  
NOTE  Twist to be measured at a distance of at least 30 mm from the end of the tube  
4.7 Workmanship   
4.7.1  A tube shall be smooth, well finished and free from defects which may affect its appearance or impair 
its serviceability (or both).   
4.7.2 Unless otherwise agreed upon, tubes shall have "mill cut" ends and any deformation caused by the 
cutting process shall not extend further than 30 mm from the cut.  
4.8 Cross -welds  
Tubes for furniture shall have no cross -welds.  
DRS 263 -4: 2020  
5                ©RSB 2020 - All rights reserved  
 5 Packing and m arking  
5.1 Packing  
Tubes shall be supplied loose or bundled. When supplied in bundles, only tubes of the same material, type, 
grade, finish, nominal length, size and wall thickness shall be bundled together.  
5.2 Marking  
The following information shall appear in  legible and indelible marking in one of official languages in Rwanda 
on a label securely attached to each tube or bundle of tubes:  
a) manufacturer’s name or trade name or trade mark;  
b) nominal diameter and thickness of the tubes  
c) type and grade designation of  the material.  
6 Sampling  
Sample of steel tube to be inspected and tested shall be taken in accordance with the requirements of table 9  
Table 9 — Sampling  
Lot size 
stainless Steel 
tubes  Sample for inspection  Sample for testing  
Sample size  Acceptance No.  
(AQL=15)  Sample size  Acceptance No. 
(AQL=15)  
50 – 90  8 0 8 0 
91 - 280  32 1 8 0 
281 - 500  50 2 8 0 
501 – 1 200  80 3 32 1 
1 201 – 3 200  125 5 32 1 
3201 – 10 000   7 32 1 
7 Inspection and methods of test  
7.1 Inspection  
Visually examine and measure (using an acceptable measuring device) each tube for compliance with  all the 
requirements of Clause 4 and Clause 5   
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 7.2 Tensile tests  
The tensile test shall be carried out in accordance with RS ISO 6892 -1, and shall be deemed to pass this test if 
it meets the  requirements indicated in 4.2  
For the determination of elongation use a gauge length of 5.65 × √𝑆𝑜 (where √𝑆𝑜 = the original cross -sectional 
area.  
7.3 Flattening test (round section)  
8.3.1 From the tube under test, cut a ring of length at least 40 mm and  so place it between two parallel flat 
surfaces (of width at least 1.5 times the length of the ring) that the weld is centred between (and parallel to) the 
flat surfaces.   
8.3.2 By applying a load to one of the flat surfaces, flatten the ring until the di stance between the two surfaces 
is 60 % ± 2 % of the original external diameter of the tube.  
8.3.3 Then examine the ring for compliance with the requirements of 4.2.2.  
7.4 Drift expansion test (round section)  
8.4.1 From the tube under test, cut a ring of le ngth at least twice the actual external diameter of the tube.  
8.4.2 Gradually force, without shock, a conical drift that has an included angle of 60° ± 1°, into the ring until the 
external diameter at the expanded end has been increased by 12 % ± 1 %, and  then examine the ring for 
compliance with the requirements of 4.2.2.  
 DRS 263 -4: 2020  
 
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