ISO 21100:2020

INTERNATIONAL ISO
STANDARD 21100
Second edition
2020-06
Air cargo unit load devices —
Performance requirements and test
parameters
Unités de charge de fret aérien — Exigences de performances et
paramètres d'essai
Reference number
ISO 21100:2020(E)
©
ISO 2020

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ISO 21100:2020(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
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ISO 21100:2020(E)

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 2
3 Terms and definitions . 2
4 Classification . 3
4.1 Types. 3
4.2 Sizes . 3
4.3 Configurations . 4
4.4 Forms . 4
4.5 Classification identifier . 4
5 Performance requirements . 4
5.1 Materials . 4
5.2 Fabrication methods and workmanship . 4
5.3 Protection . 4
5.4 Construction . 5
5.5 Marking . 5
5.6 Inspection provisions . 5
5.7 Fire protection . 5
5.8 Rapid decompression . 5
5.9 Dimensions and tolerances . 5
5.10 Strength . 6
5.10.1 Ultimate load criteria . 6
5.10.2 Restraint criteria . 6
5.10.3 Pallets and nets . 6
5.10.4 Base performance . 7
5.11 Environmental degradation . 7
6 Tests . 7
6.1 Test requirements . 7
6.2 Test parameters . 7
6.3 Test methods . 7
6.4 Test results. 8
7 Additional information . 8
7.1 Intended use . 8
7.2 Unit load device capacities . 8
7.3 Container contours . 8
7.4 Pallet configurations . 8
8 Unit load device configurations . 8
8.1 General . 8
8.2 ULD CONFIGURATION A7 .10
8.3 ULD CONFIGURATION A8 .11
8.4 ULD CONFIGURATION B7 .12
8.5 ULD CONFIGURATION B8 .13
8.6 ULD CONFIGURATION G1 .14
8.7 ULD CONFIGURATION K4 .15
8.8 ULD CONFIGURATION L5 .16
8.9 ULD CONFIGURATION L6 .18
8.10 ULD CONFIGURATION M4.20
8.11 ULD CONFIGURATION M5.21
8.12 ULD CONFIGURATION N1 .22
8.13 ULD CONFIGURATION P1 .23
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ISO 21100:2020(E)

8.14 ULD CONFIGURATION Q1 .24
8.15 ULD CONFIGURATION R1 .25
8.16 ULD CONFIGURATION S1 .27
9 Testing restraint conditions .28
9.1 General .28
9.2 RESTRAINT CONDITION (RC) A1 .29
9.3 RESTRAINT CONDITION (RC) A2 .30
9.4 RESTRAINT CONDITION (RC) G .32
9.5 RESTRAINT CONDITION (RC) K .33
9.6 RESTRAINT CONDITION (RC) L .35
9.7 RESTRAINT CONDITION (RC) N .37
9.8 RESTRAINT CONDITION (RC) P .39
9.9 RESTRAINT CONDITION (RC) Q .40
9.10 RESTRAINT CONDITION (RC) R.43
Bibliography .45
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ISO 21100:2020(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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 20, Aircraft and space vehicles,
Subcommittee SC 9, Air cargo and ground equipment.
This second edition cancels and replaces the first edition (ISO 21100:2014), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— 5.10.3.5, addition of pallets track test to ensure compatibility with straps restraint;
— 5.10.4.3, addition of stiffness requirements for containers base edges;
— Clause 8, ULD configurations A8, B8 and M5 use limited to lower deck containers;
— Clause 8, ULD configuration Q1 change to add pallet and net applicability;
— Clause 9, restraint conditions K, L, P and Q change as a result of testing experience.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
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ISO 21100:2020(E)

Introduction
This document specifies the performance and testing requirements for approved (certified) cargo
unit load devices (containers, pallets and nets) intended to be used for cargo restraint on board civil
transport aircraft.
The civil aviation requirements referred to in this document are those concerning certification
of transport aircraft and appliances to be installed aboard them, and constitute the set of design
and operation requirements internationally agreed in application of International Civil Aviation
Organization (ICAO) Annex 8, Airworthiness of aircraft, to the Convention on International Civil Aviation.
This document provides one means of compliance for unit load devices.
Dimensions and tolerances are expressed in millimetres, with dimensions in inches shown between
brackets. The nominal values of outer unit load device base dimensions are those expressed in inches.
Forces are expressed in Newton, with forces in pound-force shown between brackets.
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INTERNATIONAL STANDARD ISO 21100:2020(E)
Air cargo unit load devices — Performance requirements
and test parameters
1 Scope
This document specifies the minimum requirements for airworthiness approval of air cargo pallets,
nets and containers, generally designated as air cargo unit load devices (ULD).
This document is intended to provide a uniform technical reference for air cargo unit load devices
approval. As a prerequisite, it is presupposed that the applicable general civil aviation requirements
and the aircraft manufacturer’s approved Weight and Balance Manual are followed.
This document defines the minimum performance requirements and test parameters for air cargo
unit load devices requiring approval of airworthiness for installation in an approved aircraft cargo
compartment and restraint system that complies with the cargo restraint and occupant protection
requirements of EASA CS-25 or 14 CFR Part 25, except for the 9,0 g forward ultimate inertia force of
§ 25.561(b) (3) (ii).
This document applies to airworthiness approved air cargo unit load devices intended for carriage
on board civil transport category airplanes type certificated under EASA CS-25 or 14 CFR Part 25, or
equivalent.
This document exclusively applies to unit load devices airworthiness approval and testing parameters.
It does not apply to aircraft design or aircraft operating requirements, which are provided by the
approved Weight and Balance Manual for each aircraft type.
Other aspects that do not directly pertain to air cargo unit load devices airworthiness approval
and testing are not covered by this document and are defined in other International Standards
(see Bibliography), e.g.:
— ULD design specifications,
— ULD in service damage limits,
— ULD restraint malfunction limitations,
— ULD test methods,
— ULD load distribution models,
— ULD maximum allowable contours,
— ULD CG (centre for gravity) location control means,
— ULD pressure equalization methods,
— ULD utilization guidelines.
Air cargo unit load devices qualified prior to publication of this document were approved in accordance
with the requirements of ISO 8097:2001. This document is intended as a TSO approval reference for
all new models of unit load devices in the sizes and types it covers, in replacement of ISO 8097. For air
cargo unit load devices the size or type of which is not covered in this document, see the requirements
of ISO 8097:2001, if their size or type is contained therein, or other equivalent criteria, if not.
NOTE 1 ISO 8097 is based on USA National Aerospace Standard NAS 3610 revision 10:1990, Specification for
Cargo Unit Load Devices.
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ISO 21100:2020(E)

NOTE 2 The requirements for cargo covers are not defined in this document, except insofar as net restraint is
incorporated therein.
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.
ISO 7166, Aircraft — Rail and stud configuration for passenger equipment and cargo restraint
ISO 9788, Air cargo — Double stud tie-down fittings — Design and testing requirements
ISO 10046, Aircraft — Methodology of calculating cargo compartment volumes
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
base edge
outer perimeter of a unit load device (3.8), interfacing with the aircraft restraint system (3.7), ensuring
the required performance with contribution of adjacent parts of the complete unit load device
3.2
container
rigid structure which interfaces directly with the aircraft cargo handling and restraint
system (3.7) and alone performs all the functions of a unit load device (3.8)
3.3
cover
layer made of flexible material, used to protect cargo on a pallet (3.6)
Note 1 to entry: It may or may not incorporate a pallet net (3.4) or be permanently attached to one. If a net is
incorporated or permanently attached to the cover, the performance and testing requirements applicable to nets
in this document are applicable to the net/cover assembly.
3.4
net
webbing or rope net for restraining load onto an air cargo pallet (3.6)
3.5
numeric simulation
simulation of physical test condition and reaction of unit load device (3.8) employing numerical analysis,
computational geometry and computer graphics to obtain proof support and design verification,
validated by demonstration that parameters, algorithms and analytical methods used provide results
of at least equivalent reliability to the outcome of a specified actual test
3.6
pallet
unit load device (3.8) consisting of a flat platform with a flat undersurface of standard
dimensions, on which goods are assembled and secured by a net (3.4) before being loaded as a unit onto
the aircraft, and which interfaces directly with the aircraft handling and restraint system (3.7)
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ISO 21100:2020(E)

3.7
restraint system
equipment for supporting and restraining unit load devices (3.8) in an aircraft against the ground/
flight loads
Note 1 to entry: It usually consists of such items as rollers, side guides, and locks for securing unit load devices to
the aircraft structure. It does not include unit load devices, barrier nets (3.4) and tie-down straps.
3.8
unit load device
ULD
device for grouping, transferring and restraining cargo for transit
Note 1 to entry: It may consist of a pallet (3.6) with a net (3.4) or it may be a container (3.2).
4 Classification
4.1 Types
Type 1 (for reference only): Unit load devices (ULDs) designed for use in an approved aircraft restraint
system that conforms to all flight and ground cargo restraint and occupant protection requirements of
EASA CS-25 or 14 CFR Part 25, including the 9,0 g forward ultimate inertia force of § 25.561 (b)(3)(ii).
NOTE Type 1 ULDs are not shown in this document. Refer to ISO 8097:2001 (NAS 3610 revision 10).
Type 2: ULDs designed for use in an approved aircraft cargo compartment and restraint system that
conforms to the flight and ground cargo restraint and occupant protection requirements of CCAR-
25, JAS Part 3, EASA CS-25 or 14 CFR Part 25, except for the 9,0 g forward ultimate inertia force of
§ 25.561(b) (3) (ii), which is complied with either by supplementary installation of a barrier net or
bulkhead, or by specifying an approved placement of the ULD in the aircraft.
4.2 Sizes
This document provides for the sizes of unit load devices listed in Table 1, expressed as nominal
dimensions in the overall plan form of a pallet or a container base, in mm (inches).
NOTE Throughout this document, dimensions are expressed in SI units, with inch/pound system values
additionally shown between brackets in order to conform to international air cargo industry usage.
Table 1 — Sizes
Size Nominal dimension
A 2 235 mm × 3 175 mm (88 in × 125 in)
B 2 235 mm × 2 743 mm (88 in × 108 in)
G 2 438 mm × 6 058 mm (96 in × 238.5 in)
K 1 534 mm × 1 562 mm (60.4 in × 61.5 in)
L 1 534 mm × 3 175 mm (60.4 in × 125 in)
M 2 438 mm × 3 175 mm (96 in × 125 in)
N 1 562 mm × 2 438 mm (61.5 in × 96 in)
P 1 198 mm × 1 534 mm (47 in × 60.4 in)
Q 1 534 mm × 2 438 mm (60.4 in × 96 in)
R 2 438 mm × 4 978 mm (96 in × 196 in)
S 1 562 mm × 2 235 mm (61.5 in × 88 in)
NOTE  Size codes C, D, E, F, H, I, J, O have been intentionally omitted in this document in order to
be in agreement with the industry's (IATA ULD Regulations) identification coding system.
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ISO 21100:2020(E)

4.3 Configurations
4.3.1 This document provides for variations of configuration among pallets, nets and containers of the
same type and size, specified in Clause 8 and listed in Table 2. Variations in pallet/net attachment and
special interface requirements between components of unit load devices when affecting airworthiness
are specified by the configuration drawings. Configurations are denoted by sequence numbers and are
identified in accordance with 4.5.
4.3.2 The applicable restraint conditions to be used for testing each unit load device configuration are
specified in Clause 9 and listed in Table 18, based on testing of worst-case analysis.
4.3.3 The ULD restraint conditions and ultimate loads included herein are intended to represent a
worst-case capability for the ULD. They are not intended to represent aircraft cargo handling system
restraint designs. Actual aircraft implementations may vary from the ULD test parameters stated herein
in such areas as number and spacing of restraints, among others, as long as they stay within the worst-
case ULD capabilities.
4.4 Forms
Form C = Container
Form N = Net
Form P = Pallet
4.5 Classification identifier
The pallets, nets, and containers described in this document shall be identified by the numbers
derived as shown. Types, sizes, configurations, and forms shall be limited to those in configuration
drawings. “ISO 21100-2A7P” = Type 2, Size A (2 235 mm × 3 175 mm, 88 in × 125 in), Configuration
sequence A7, Pallet.
5 Performance requirements
5.1 Materials
The suitability and durability of materials used shall be established on the basis of experience or tests.
Materials shall conform to approved industry specifications that ensure their having the strength and
other properties specified in the design data.
5.2 Fabrication methods and workmanship
The methods of fabrication used shall produce a consistently sound structure. If the fabrication
processes (such as gluing or heat treatment) require close control to reach their objectives, the processes
shall be performed under an approved process specification. Workmanship shall be consistent with
high-grade aircraft manufacturing practices.
5.3 Protection
All components of the unit load devices shall be suitably protected against deterioration or loss of
strength in service due to weathering, corrosion, abrasion or other causes where the type of material
used requires such protection. The unit load device shall have provisions for ventilation or drainage
where necessary for protection.
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ISO 21100:2020(E)

5.4 Construction
The unit load device shall be constructed to adequately encompass the cargo and shall provide
for proper support and restraint of the cargo. All components shall be designed to withstand rough
handling. The design shall minimize the possibility of improper installation. All pallet/net attachment
devices shall conform to ISO 7166 track and stud configuration, for single stud fittings, or ISO 9788 for
double stud fittings.
5.5 Marking
Each pallet, net, and container shall be legibly and permanently marked in an area clearly visible after
the article is loaded with cargo, with the following information:
a) the name and address of the manufacturer;
b) the weight of the article to the nearest kilogram or pound, with the applicable unit;
c) the serial number and
...