EN ISO 13351:2024

SLOVENSKI STANDARD
oSIST prEN ISO 13351:2023
01-december-2023
Industrijski ventilatorji - Mere (ISO/DIS 13351:2023)
Fans - Dimensions (ISO/DIS 13351:2023)
Ventilatoren - Abmessungen (ISO/DIS 13351:2023)
Ventilateurs - Dimensions (ISO/DIS 13351:2023)
Ta slovenski standard je istoveten z: prEN ISO 13351
ICS:
23.120 Zračniki. Vetrniki. Klimatske Ventilators. Fans. Air-
naprave conditioners
oSIST prEN ISO 13351:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

oSIST prEN ISO 13351:2023
oSIST prEN ISO 13351:2023
DRAFT INTERNATIONAL STANDARD
ISO/DIS 13351
ISO/TC 117 Secretariat: BSI
Voting begins on: Voting terminates on:
2023-10-16 2024-01-08
Fans — Dimensions
Ventilateurs — Dimensions
ICS: 23.120
This document is circulated as received from the committee secretariat.
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
ISO/CEN PARALLEL PROCESSING
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
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Reference number
NATIONAL REGULATIONS.
ISO/DIS 13351:2023(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. © ISO 2023

oSIST prEN ISO 13351:2023
ISO/DIS 13351:2023(E)
DRAFT INTERNATIONAL STANDARD
ISO/DIS 13351
ISO/TC 117 Secretariat: BSI
Voting begins on: Voting terminates on:

Fans — Dimensions
Ventilateurs — Dimensions
ICS: 23.120
This document is circulated as received from the committee secretariat.
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
© ISO 2023
ISO/CEN PARALLEL PROCESSING
THEREFORE SUBJECT TO CHANGE AND MAY
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
NOT BE REFERRED TO AS AN INTERNATIONAL
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NATIONAL REGULATIONS.
Website: www.iso.org ISO/DIS 13351:2023(E)
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NOTIFICATION OF ANY RELEVANT PATENT
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ii
PROVIDE SUPPORTING DOCUMENTATION. © ISO 2023

oSIST prEN ISO 13351:2023
ISO/DIS 13351:2023(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and symbols . 1
4 Requirements . 3
4.1 General . 3
4.2 Circular flanges . 4
4.3 Rectangular flanges . 7
4.4 Designation of fan size . 11
Bibliography .13
iii
oSIST prEN ISO 13351:2023
ISO/DIS 13351:2023(E)
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 13351 was prepared by Technical Committee ISO/TC 117, Fans.
This third edition cancels and replaces the second edition (ISO 13351:2009), of which it constitutes a
minor revision.
iv
oSIST prEN ISO 13351:2023
ISO/DIS 13351:2023(E)
Introduction
This International Standard gives dimensional details of circular and rectangular flanges of fans in
addition to specifying the fan size designation. For circular flanges, the values specified in ISO 6580
have been retained for light-duty fans, in parallel with those values given in Tables 3 and 4 for medium-
and heavy-duty fans.
While it does not constrain the manufacturer's choice of flange details, this International Standard
facilitates interchangeability, thereby helping to reduce technical barriers to trade.
Throughout this International Standard, the principal dimensions are based on the rounded values of
preferred numbers given in ISO 497.
v
oSIST prEN ISO 13351:2023
oSIST prEN ISO 13351:2023
DRAFT INTERNATIONAL STANDARD ISO/DIS 13351:2023(E)
Fans — Dimensions
1 Scope
This International Standard specifies the dimensions of the circular and rectangular flanges of
general-purpose fans, as well as the fan size designations. It is not applicable to cross-flow fans or to fan
appliances used for individual household or similar applications.
For circular flanges, it provides for three different flange series: one for light-duty casing thicknesses,
another for medium-duty fans and the third for heavy-duty fans as used on sea-going vessels or in
heavy industry.
In order not to restrict fan design unduly, only the pitch diameter, hole numbers and hole diameters
are specified. Flange thickness, as well as internal and external flange diameters, may be chosen freely
within the limits of good engineering practice.
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 3, Preferred numbers — Series of preferred numbers
ISO 273, Fasteners — Clearance holes for bolts and screws
ISO 7089, Plain washers — Normal series — Product grade A
ISO 13349-1, Fans — Vocabulary and definitions of categories — Part 1: Vocabulary
ISO 13349-2, Fans — Vocabulary and definitions of categories — Part 2: Categories
3 Terms, definitions and symbols
For the purposes of this document, the terms and definitions given in ISO 13349 and the following
terms, definitions and symbols apply.
3.1
light‑duty fan
fan suitable for air that is non-toxic, not saturated, non-corrosive, non-flammable, free from abrasive
particles, and not exceeding a temperature of 80 °C, or 40 °C if the motor or the fan bearings are in the
air stream, and for pressures up to 2 kPa
Note 1 to entry: Note1 to entry: See Table 1.
3.2
medium‑duty fan
fan with flange dimensions as specified in Figure 4 and Table 2 and suitable for pressures up to 10 kPa
3.3
heavy‑duty fan
fan with larger flange dimensions as specified in Figure 4 and Table 3 and suitable for pressures up to
40 kPa
oSIST prEN ISO 13351:2023
ISO/DIS 13351:2023(E)
3.4
nominal impeller tip diameter
D
diameter of the impeller tip on which the design of the fan is based
Note 1 to entry: Note1 to entry: See Figures 1 to 3.
Symbol Parameter Unit
D nominal impeller tip diameter mm
a
D impeller tip diameter mm (see Figures 1 to 3)
R
d internal duct diameter mm
d pitch circle diameter mm
d hole diameter mm
d bolt diameter mm
d washer diameter mm
e casing thickness mm
g hole offset mm
l arc length between bolt holes mm
N number of holes
P pitch mm
α angle between bolt holes degrees
a
Reference 3.7.4 of ISO 13349-1, i.e. maximum diameter measured over the tips of the blades of the impeller.

b
D may be smaller than, larger than or equal to D .
R
Figure 1 — Impeller — Centrifugal fan
oSIST prEN ISO 13351:2023
ISO/DIS 13351:2023(E)
b
D may be smaller than, larger than or equal to D .
R
Figure 2 — Impeller — Axial‑flow fan

b
D may be smaller than, larger than or equal to D .
R
Figure 3 — Impeller — Mixed‑flow fan
4 Requirements
4.1 General
This International Standard adopts the Renard R 20 series according to ISO 497 as the nominal
dimensions (D) for impeller tip diameters, the inside diameters of circular flanges and the inside
lengths of the sides of rectangular flanges. It takes into account the maximum casing thicknesses likely
to be used for general-purpose fans, as well as typical manufacturing tolerances representative of
engineering “good practice”.
The smallest practical pitch circle diameter can be related to the inside diameter of the casing, the
casing thickness, the size of the weld fillet or bend radius at the junction of the flange and the casing, and
oSIST prEN ISO 13351:2023
ISO/DIS 13351:2023(E)
the normal washer diameter. Light-duty circular flanges might not be suitable for the use of open-ended
spanners in all cases.
This International Standard accepts that the number and diameter of bolts or screws cannot be
established on a theoretical basis. Practical experience of satisfactory service, optimum cost of
installation and manufacture, as well as dimensional tolerances of production are the most important
considerations.
The dimensions of circular and rectangular flanges are given in sizes corresponding to nominal
diameters from 100 mm to 2 000 mm (3 550 mm for heavy duty fans, Table 3). In the smaller sizes
(below about 200 mm) flange details may be determined by the customer's specification. However,
where this is not the case, then the specifications of this International Standard are to be applied.
4.2 Circular flanges
The number of flange holes is divisible by four to permit the orientation of cylindrical cased fans at
positions of 90°. The holes are disposed equally on each side of the centrelines of the fan. This permits a
flange to be divided in half if a split casing is required. It also allows better access to the fixings on the
remote side of a fan in a confined installation.
When an intermediate fan size is required, the R 40 series in accordance with ISO 3 shall be used to
obtain the nominal inside diameter. The flange details shall be interpreted from the next larger R 20
size.
In exceptional circumstances, when even smaller increments of fan size are required, it is recommended
that the R 80 series be used.
See Figure 4.
Figure 4 — Dimensions — Circular flanges
oSIST prEN ISO 13351:2023
ISO/DIS 13351:2023(E)
Table 1 — Dimensions — Circular flanges — Light‑duty fans
Dimensions in millimetres
dD−
D d N α d d d e
1 2 3 4 max.
100 120 10 4 90 7 M6 12,5 1,6
112 137 12,5 4 90 7 M6 12,5 2
125 150 12,5 4 90 7 M6 12,5 2
140 165 12,5 4 90 7 M6 12,5 2
160 185 12,5 4 90 7 M6 12,5 2
180 205 12,5 4 90 7 M6 12,5 2
200 225 12,5 4 90 7 M6 12,5 2
224 254 15 4 90 7 M6 12,5 2
250 280 15 4 90 10 M8 17 2,5
280 320 20 4 90 10 M8 1
...