ISO 10799-2:2011

INTERNATIONAL ISO
STANDARD 10799-2
First edition
2011-09-15
Cold-formed welded structural hollow
sections of non-alloy and fine grain
steels —
Part 2:
Dimensions and sectional properties
Profils creux de construction formés à froid, soudés, en acier non allié
ou à grains fins —
Partie 2: Dimensions et caractéristiques du profil

Reference number
©
ISO 2011
©  ISO 2011
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Published in Switzerland
ii © ISO 2011 – All rights reserved

Contents Page
Foreword . iv
1  Scope . 1
2  Normative references . 1
3  Terms and definitions . 1
4  Symbols . 1
5  Information to be supplied by the purchaser . 2
6  Tolerances . 2
7  Measurement of size and shape . 4
7.1  General . 4
7.2  Outside dimension . 4
7.3  Thickness . 5
7.4  Out-of-roundness . 5
7.5  Concavity and convexity . 5
7.6  Squareness of sides . 6
7.7  External corner profile . 6
7.8  Twist . 7
7.9  Straightness . 8
8  Dimensions and sectional properties . 8
Annex A (normative) Formulae for calculation of sectional properties . 25

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
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. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 10799-2 was prepared by Technical Committee ISO/TC 5, Ferrous metal pipes and metallic fittings,
Subcommittee SC 1, Steel tubes.
This first edition of ISO 10799-2 cancels and replaces ISO 4019:2001, of which it constitutes a minor revision.
In particular, better grouping of several documents by subject area and minor editorial improvements have
been carried out.
ISO 10799 consists of the following parts, under the general title Cold-formed welded structural hollow
sections of non-alloy and fine grain steels:
 Part 1: Technical delivery conditions
 Part 2: Dimensions and sectional properties

iv © ISO 2011 – All rights reserved

INTERNATIONAL STANDARD ISO 10799-2:2011(E)

Cold-formed welded structural hollow sections of non-alloy and
fine grain steels —
Part 2:
Dimensions and sectional properties
1 Scope
This part of ISO 10799 specifies the tolerances for cold-formed welded circular, square and rectangular
structural hollow sections, and gives the dimensions and sectional properties for a range of standard sizes.
NOTE For the technical delivery requirements, see ISO 10799-1.
2 Normative references
The following referenced documents are indispensable for the application 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.
ISO 10799-1, Cold-formed welded structural hollow sections of non-alloy and fine grain steels — Part 1:
Technical delivery conditions
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 10799-1 apply.
4 Symbols
For the purposes of this document, the symbols given in Table 1 apply.
Table 1 — Symbols
Symbol Unit Definition
A cm Cross-sectional area
A m /m Surface area per metre length
s
Nominal length of side of a square hollow section
B mm
Nominal length of the shorter side of a rectangular hollow section
C ; C mm Length of external corner profile of a square or rectangular hollow section
1 2
C cm Torsional modulus constant
t
D mm Nominal outside diameter of a circular hollow section

Table 1 (continued)
Symbol Unit Definition
Maximum and minimum outside diameter of a circular hollow section, measured in the same
D ; D mm
max min
plane
e mm Deviation from straightness
H mm Nominal length of the longer side of a rectangular hollow section
I cm Second moment of area
I cm Torsional-inertia constant (polar moment of inertia for circular hollow sections only)
t
i cm Radius of gyration
L mm Length
M kg/m Mass per unit length
O % Out-of-roundness
R mm External corner radius of a square or rectangular hollow section
T mm Nominal thickness
V mm Total twist
V mm Twist measured at one end of a section
W cm Elastic section modulus
el
W cm Plastic section modulus
pl
x mm Concavity of a side of a square or rectangular hollow section
x mm Convexity of a side of a square or rectangular hollow section
XX — Axis of cross-section: major axis of a rectangular hollow section
YY — Axis of cross-section: minor axis of a rectangular hollow section
 Degrees Angle between adjacent sides of a square or rectangular hollow section

5 Information to be supplied by the purchaser
The following mandatory information taken from this part of ISO 10799 shall be supplied by the purchaser at
the time of enquiry and ordering:
a) the type of length, and the length or the length range (see Table 4);
b) the dimensions (see Clause 8).
NOTE This information is included in the list of information to be supplied by the purchaser contained in 5.1 of
ISO 10799-1:—.
6 Tolerances
Tolerances on the dimensions and mass of cold-formed hollow sections shall not exceed the values given in
Table 2 for shape and mass, Table 3 for external corner profiles, Table 4 for length and, in the case of
submerged-arc-welded hollow sections, Table 5 for the height of the internal and external weld beads.
The internal corners of square and rectangular hollow sections shall be rounded.
NOTE The internal corner profile is not specified.
2 © ISO 2011 – All rights reserved

Table 2 — Tolerances
Characteristic Circular hollow sections Square and rectangular hollow sections
Side length
Tolerance
mm
Outside dimensions (D, B and  1 %, with a minimum of  0,5 mm and a H, B  100  1 %, with a
H) maximum of  10 mm. minimum of
 0,5 mm
100  H, B  200  0,8 %
H, B > 200  0,6 %
Thickness, T For D  406,4 mm T  5 mm:  10 %
T  5 mm:  10 %
T  5 mm:  0,50 mm T  5 mm:  0,50 mm
For D  406,4 mm
 10 % with a maximum of  2 mm
Out-of-roundness, O 2 % for hollow sections having a diameter
—
a
to thickness ratio not exceeding 100
b
Concavity/convexity — Max. 0,8 %, with a minimum of 0,5 mm
Squareness of sides — 90°  1°
External corner profile — See Table 3
Twist, V — 2 mm plus 0,5 mm/m length
Straightness 0,2 % of total length 0,15 % of total length
Mass, M, per unit length  6 % on individual lengths
a
Where the diameter to thickness ratio exceeds 100, the tolerance on out-of-roundness shall be agreed.
b
The tolerance on convexity and concavity is dependent of the tolerance on outside dimensions.

Table 3 — External corner profile
Thickness External corner profile

a
T C , C , or R
1 2
mm mm
T  6 1,6 T to 2,4 T
6  T  10 2,0 T to 3,0 T
T  10 2,4 T to 3,6 T
a
The sides need not be tangential to the corner arcs.

a
Table 4 — Tolerances on length
Range
Type of length Tolerance
mm
Random length 4 000 to 16 000 with a range of 10 % of sections supplied may be below
2 000 per order item. the minimum for the ordered range, but
not less than 75 % of the minimum of
the range.
50 mm
Approximate length  4 000
Exact length 5 mm
 6 000
15 mm
 6 000 to  10 000
5 mm 1 mm/m
 10 000
a
The purchaser shall indicate in the enquiry and order the type of length required and the length or length range as
appropriate.
Table 5 — Tolerance on height of internal and external weld
bead for submerged-arc-welded hollow sections
Thickness Maximum weld bead height
T
mm mm
 14,2 3,5
 14,2 4,8
7 Measurement of size and shape
7.1 General
All external dimensions including out-of-roundness shall be measured at a distance from the end of the hollow
section of not less than D for circular sections, B for square sections or H for rectangular sections, with a
minimum of 100 mm.
7.2 Outside dimension
For circular hollow sections, the diameter, D, shall be measured. A calliper gauge, circumference tape or other
suitable device may be used at the discretion of the manufacturer.
Dimensions B and H shall be measured at a position within 5 mm from the start of the external corner profile
as shown in Figure 1.
4 © ISO 2011 – All rights reserved

Dimensions in millimetres
a
This dimension is a maximum when measuring B or H and a minimum when measuring T.
Figure 1 — Limiting cross-sectional positions for measuring the dimensions B, H and T for square or
rectangular hollow sections
7.3 Thickness
The thickness, T, shall be measured at a position of not less than 2T from the weld.
The limiting cross-sectional positions for measuring the thickness of square and rectangular hollow sections
are shown in Figure 1.
NOTE Thickness is normally measured within a distance of half the outside diameter or half the longer side length
from the end of the section.
7.4 Out-of-roundness
The out-of-roundness, O, of a circular hollow section shall be calculated, as a percentage, from the following
equation:
DD
max min
O100
D
7.5 Concavity and convexity
The concavity, x , or the convexity, x , of the sides of a square or rectangular hollow section shall be
1 2
measured as shown in Figure 2.
The percentage concavity or convexity shall be calculated using the following:
xx xx
12 12
100; 100;100; 100
BB H H
where B and H are the lengths of the sides containing the concavity, x , or the convexity, x
1 2.
Figure 2 — Measurement of concavity/convexity of square or rectangular hollow sections
7.6 Squareness of sides
The deviation from squareness of the sides of a square or rectangular hollow section is defined as the
difference between 90° and  as shown in Figure 3.

Deviation from squareness = 90°  
Figure 3 — Squareness of sides of square or rectangular hollow sections
7.7 External corner profile
The external corner profile of a square or rectangular hollow section shall be measured in accordance with a)
or b), at the discretion of the manufacturer.
a) Measure the external corner radius, R. Use a radius gauge or other suitable device.
b) Measure the length of the external corner profile (C and C in Figure 4).
1 2
6 © ISO 2011 – All rights reserved

Figure 4 — External corner profile of square or rectangular hollow sections
7.8
...