ISO/IEC 26702:2007

INTERNATIONAL ISO/IEC
STANDARD 26702
IEEE
Std 1220-2005
First edition
2007-07-15
Systems engineering — Application and
management of the systems engineering
process
Ingénierie des systèmes —- Application et management du processus
d'ingénierie des systèmes
Reference number
IEEE
Std 1220-2005
IEEE Std 1220-2005
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.

ISO
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
ii © ISO 2007 – All rights reserved

™IEEE Std 1220-2005
(Revision of
IEEE Std 1220-1998)
TM
IEEE Standard for Application and
Management of the Systems
Engineering Process
IEEE Computer Society
Sponsored by the
Software and Systems Engineering Standards Committee
9 September 2005
Print: SH95334
3 Park Avenue, New York, NY10016-5997, USA
PDF: SS95334
™
IEEE Std 1220 -2005
(Revision of
IEEE Std 1220-1998)
IEEE Standard for Application and
Management of the Systems
Engineering Process
Sponsor
Software and Systems Engineering Standards Committee
of the
IEEE Computer Society
Approved 20 March 2005
IEEE-SA Standards Board
Abstract: The interdisciplinary tasks, which are required throughout a system’s life cycle to
transform customer needs, requirements, and constraints into a system solution, are defined. In
addition, the requirements for the systems engineering process and its application throughout the
product life cycle are specified. The focus of this standard is on engineering activities necessary to
guide product development while ensuring that the product is properly designed to make it
affordable to produce, own, operate, maintain, and eventually to dispose of, without undue risk to
health or the environment.
Keywords: acquire, analysis, architecture, building block, design, development, component,
hardware, interface, life cycle processes, software, supplier, synthesis, system, system life cycle,
systems engineering, technical management, validation, verification
The Institute of Electrical and Electronics Engineers, Inc.
3 Park Avenue, New York, NY 10016-5997, USA
All rights reserved. Published 9 September 2005. Printed in the United States of America.
IEEE is a registered trademark in the U.S. Patent & Trademark Office, owned by the Institute of Electrical and Electronics
Engineers, Incorporated.
PMBOK is a registered mark of Project Management, Inc.
Print: ISBN 0-7381-4691-9  SH95334
PDF: ISBN 0-7381-4692-7  SS95334
No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior
written permission of the publisher.

IEEE Std 1220-2005
International Standard ISO/IEC 26702:2007(E)
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are members of
ISO or IEC participate in the development of International Standards through technical committees
established by the respective organization to deal with particular fields of technical activity. ISO and IEC
technical committees collaborate in fields of mutual interest. Other international organizations, governmental
and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information
technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of the joint technical committee is to prepare International Standards. Draft International
Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as
an International Standard requires approval by at least 75 % of the national 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 and IEC shall not be held responsible for identifying any or all such patent rights.
ISO/IEC 26702 was prepared by IEEE (as IEEE Std 1220-2005) and was adopted, under a special “fast-track
procedure”, by Joint Technical Committee ISO/IEC JTC 1, Information technology, Subcommittee SC 7,
Software and systems engineering, in parallel with its approval by national bodies of ISO and IEC. The IEEE
Computer Society will cooperate in the maintenance of this International Standard as a Category A liaison to
SC 7.
International Organization for Standardization/International Electrotechnical Commission
Case postale 56 • CH-1211 Genève 20 • Switzerland

IEEE Standards documents are developed within the IEEE Societies and the Standards Coordinating Committees of the
IEEE Standards Association (IEEE-SA) Standards Board. The IEEE develops its standards through a consensus develop-
ment process, approved by the American National Standards Institute, which brings together volunteers representing varied
viewpoints and interests to achieve the final product. Volunteers are not necessarily members of the Institute and serve
without compensation. While the IEEE administers the process and establishes rules to promote fairness in the consensus
development process, the IEEE does not independently evaluate, test, or verify the accuracy of any of the information con-
tained in its standards.
Use of an IEEE Standard is wholly voluntary. The IEEE disclaims liability for any personal injury, property or other dam-
age, of any nature whatsoever, whether special, indirect, consequential, or compensatory, directly or indirectly resulting
from the publication, use of, or reliance upon this, or any other IEEE Standard document.
The IEEE does not warrant or represent the accuracy or content of the material contained herein, and expressly disclaims
any express or implied warranty, including any implied warranty of merchantability or fitness for a specific purpose, or that
the use of the material contained herein is free from patent infringement. IEEE Standards documents are supplied “AS IS.”
The existence of an IEEE Standard does not imply that there are no other ways to produce, test, measure, purchase, market,
or provide other goods and services related to the scope of the IEEE Standard. Furthermore, the viewpoint expressed at the
time a standard is approved and issued is subject to change brought about through developments in the state of the art and
comments received from users of the standard. Every IEEE Standard is subjected to review at least every five years for revi-
sion or reaffirmation. When a document is more than five years old and has not been reaffirmed, it is reasonable to conclude
that its contents, although still of some value, do not wholly reflect the present state of the art. Users are cautioned to check
to determine that they have the latest edition of any IEEE Standard.
In publishing and making this document available, the IEEE is not suggesting or rendering professional or other services
for, or on behalf of, any person or entity. Nor is the IEEE undertaking to perform any duty owed by any other person or
entity to another. Any person utilizing this, and any other IEEE Standards document, should rely upon the advice of a
competent professional in determining the exercise of reasonable care in any given circumstances.
Interpretations: Occasionally questions may arise regarding the meaning of portions of standards as they relate to specific
applications. When the need for interpretations is brought to the attention of IEEE, the Institute will initiate action to prepare
appropriate responses. Since IEEE Standards represent a consensus of concerned interests, it is important to ensure that any
interpretation has also received the concurrence of a balance of interests. For this reason, IEEE and the members of its
societies and Standards Coordinating Committees are not able to provide an instant response to interpretation requests except
in those cases where the matter has previously received formal consideration. At lectures, symposia, seminars, or educational
courses, an individual presenting information on IEEE standards shall make it clear that his or her views should be considered
the personal views of that individual rather than the formal position, explanation, or interpretation of the IEEE.
Comments for revision of IEEE Standards are welcome from any interested party, regardless of membership affiliation with
IEEE. Suggestions for changes in documents should be in the form of a proposed change of text, together with appropriate
supporting comments. Comments on standards and requests for interpretations should be addressed to:
Secretary, IEEE-SA Standards Board
445 Hoes Lane
Piscataway, NJ 08854
USA
NOTE−Attention is called to the possibility that implementation of this standard may require use of subject
matter covered by patent rights. By publication of this standard, no position is taken with respect to the
existence or validity of any patent rights in connection therewith. The IEEE shall not be responsible for
identifying patents for which a license may be required by an IEEE standard or for conducting inquiries into the
legal validity or scope of those patents that are brought to its attention.
Authorization to photocopy portions of any individual standard for internal or personal use is granted by the Institute of
Electrical and Electronics Engineers, Inc., provided that the appropriate fee is paid to Copyright Clearance Center. To
arrange for payment of licensing fee, please contact Copyright Clearance Center, Customer Service, 222 Rosewood Drive,
Danvers, MA 01923 USA; +1 978 750 8400. Permission to photocopy portions of any individual standard for educational
classroom use can also be obtained through the Copyright Clearance Center.

Introduction
This introduction is not part of IEEE Std 1220-2005, IEEE Standard for Application and Management of the Systems
Engineering Process.
History
IEEE Std 1220 was initially published in January 1995 as a trial-use standard. After the two-year trial-use
period, the document was revised and balloted in 1998 for full publication in 1999.
The International Organization for Standardization (ISO) and the International Electrotechnical Commission
(IEC) formed a joint body to collaborate in fields of mutual interest for worldwide standardization efforts.
ISO/IEC established a joint technical committee for international standards development, ISO/IEC JTC 1,
Information Technology. In parallel with IEEE Std 1220 developments, ISO/IEC JTC 1, Subcommittee 7
a
(SC7), Software and Systems Engineering, began generation of ISO/IEC 15288:2002 [B3]. ISO/IEC
15288:2002 provides a framework based on a broad set of processes that an organization or project may
employ to perform or manage the stages of a system’s life cycle. ISO/IEC 15288:2002 supports the full life
cycle of systems—from conception through retirement—as well as the acquisition and supply of systems.
It is the intent of ISO/IEC 15288:2002 to establish standard life cycle process descriptions suitable for most
man-made systems. As such, the processes and terminology of the standard are defined at an appropriately
high level of abstraction. ISO/IEC 15288:2002 does not prescribe, nor provide, detailed system engineering
process definitions or methods and procedures to address detail process requirements derived from the
application of this standard. ISO/IEC TR 19760:2003 [B4], the companion guide for ISO/IEC 15288:2002,
lists several standards, including IEEE Std 1220-1998, that cover engineering disciplines at a lower-tier
level and are suitable for implementation with ISO/IEC 15288:2002.
This revision of IEEE Std 1220-1998 is a result of an ongoing harmonization of the standards of the IEEE
Computer Society’s Software and Systems Engineering Standards Committee (S2ESC) and the
corresponding international standards committee, ISO/IEC JTC1/SC7. This initial alignment of IEEE Std
1220-1998 with ISO/IEC 15288:2002 was developed in cooperation with ISO/IEC JTC1/SC7 and included
participation of the International Council on Systems Engineering (INCOSE). The next step towards
harmonization of these two standards would be the submission of IEEE Std 1220-2005 for a “fast-track”
ballot with ISO/IEC JTC1/SC7 followed by a coordinated revision.
The IEEE Computer Society has embraced the top-level framework provided by ISO/IEC 15288:2002 and
™
has adopted ISO/IEC 15288 as IEEE Std 15288
-2004. The IEEE Computer Society offered to align IEEE
Std 1220-1998 with ISO/IEC 15288:2002 to facilitate the joint use of the two standards to manage system
engineering efforts. The purpose of this revision of IEEE Std 1220-1998 is to identify key similarities and
differences in the two standards and demonstrate how they can be used together while minimizing the
impact of ISO/IEC 15288:2002 on current IEEE Std 1220-1998 users who may not employ ISO/IEC
15288:2002.
The key differences between this version of the standard, IEEE Std 1220-2005, and the 1998 version are as
follows:
a) Inclusion of explanations regarding key differences between IEEE Std 1220-1998 and ISO/IEC
15288:2002 in areas such as terminology and structure
b) Minimal adjustments to some IEEE Std 1220-1998 terms and definitions for alignment with ISO/
IEC publication requirements
c) Clarification of the distinction between requirements and recommendations of the standard
a
The numbers in brackets correspond to those of the bibliography in Annex D.
d) Update of the conformance clause for alignment with IEEE standards style and rules
Most of the IEEE Std 1220-1998 content remains the same in this version. Explanations to facilitate use of
IEEE Std 1220 with ISO/IEC 15288:2002 are contained in a new Annex C.
Purpose
This standard defines the requirements for an enterprise’s total technical effort related to development of
products (including computers and software) and processes that will provide life cycle support (sustain and
evolve) for the products. It prescribes an integrated technical approach to engineering a system and requires
the application and management of the systems engineering process throughout a product life cycle. The
systems engineering process is applied recursively to the development or incremental improvement of a
product to satisfy market requirements and to simultaneously provide related life cycle processes for product
development, manufacturing, test, distribution, operation, support, training, and disposal.
The concept of systems engineering embodied in this standard provides an approach for product
development in a system context. It is not meant to describe what an organizational entity called systems
engineering does or a job position for which a systems engineer is responsible. Rather, it encompasses what
all organizational entities and all enterprise and project personnel must accomplish to produce a quality,
competitive product that will be marketable, will provide an acceptable return on investment to the
enterprise, will achieve stakeholder satisfaction, and will meet public expectations.
The fundamental systems engineering objective is to provide high-quality products and services, with the
correct people and performance features, at an affordable price, and on time. This involves developing,
producing, testing, and supporting an integrated set of products (hardware, software, people, data, facilities,
and material) and processes (services and techniques) that is acceptable to stakeholders, satisfies enterprise
and external constraints, and considers and defines the processes for developing, producing, testing,
handling, operating, and supporting the products and life cycle processes. This objective is achieved by
simultaneous treatment of product and process content to focus project resources and design decisions for
the establishment of an effective system design. This involves an integrated handling of all elements of a
system, including those related to manufacturing, test, distribution, operations, support, training, and
disposal.
Notice to users
Errata
Errata, if any, for this and all other standards can be accessed at the following URL: http://
standards.ieee.org/reading/ieee/updates/errata/index.html. Users are encouraged to check this URL for
errata periodically.
Interpretations
Current interpretations can be accessed at the following URL: http://standards.ieee.org/reading/ieee/interp/
index.html.
Patents
Attention is called to the possibility that implementation of this standard may require use of subject matter
covered by patent rights. By publication of this standard, no position is taken with respect to the existence or
validity of any patent rights in connection therewith. The IEEE shall not be responsible for identifying
iv Copyright © 2005 IEEE. All rights reserved.

patents or patent applications for which a license may be required to implement an IEEE standard or for
conducting inquiries into the legal validity or scope of those patents that are brought to its attention.
Participants
At the time this standard was completed, the IEEE 1220 Revision Working Group had the following
membership:
Teresa (Terry) Doran, Chair and Editor
Ken Crowder, ISO/IEC JTC1/SC7 Liaison
James Moore, IEEE CS Liaison to ISO/IEC JTC1/SC7
Lorraine Pajerek, INCOSE Organizational Representative
Werner Altmann Mark Henley Ken Ptack
Jim Armstrong Ron Kohl Karen Richter
Stuart Arnold Jerome (Jerry) Lake Garry Roedler
Randy Case Jean-Philippe Lerat Robert J. Schaaf
John Clark Elizabeth Lotsu Richard Schmidt
Paul Croll John H. Mee Robert Skalamera
Alain Faisandier Frederick I. Moxley Thomas Starai
Kevin Forsburg John Napier Mark Wilson
Rich Harwell Steve Olson Matthew Young
Robert Peterson
The following members of the individual balloting committee voted on this standard. Balloters may have
voted for approval, disapproval, or abstention.
Edward Bartlett Clint Early, Jr. Jacques Mathot
Richard Biehl Christof Ebert James Moore
Stephen Blanchette William Eventoff Dennis Nickle
Juris Borzovs John Fendrich Lou Pinto
Bruce Bullock Yaacov Fenster Gerald Radack
Joseph Butchko Roger Fujii Annette Reilly
Dino Butorac Jean-Denis Gorin David Rockwell
Keith Chow Lewis Gray Garry Roedler
Antonio M. Cicu Michael Grimley Helmut Sandmayr
Mark Heinrich
Paul Croll James Sanders
Gregory Daich John Horch Robert J. Schaaf
Geoffrey Darnton Peeya Iwagoshi Carl Singer
Taz Daughtrey Thomas M. Kurihara Mitchell Smith
Maulik Dave Joerg Kampmann Luca Spotorno
Perry DeWeese Piotr Karocki Thomas Starai
Dr. Guru Dutt Dhingra Ron Kenett David Walden
Teresa (Terry) Doran Carol Long John Walz
Einar Dragstedt Yuhai Ma Oren Yuen
Scott Duncan Joseph Marshall Li Zhang
The following organizational representative voted on this standard:
Lorraine Pajerek, INCOSE
In addition, this standard was coordinated with the following organizations:
GEIA NDIA
When the IEEE-SA Standards Board approved this standard on 20 March 2005, it had the following
membership:
Steve M. Mills, Chair
Richard H. Hulett, Vice Chair
Don Wright, Past Chair
Judith Gorman, Secretary
Mark D. Bowman Raymond Hapeman Glenn Parsons
Dennis B. Brophy Ronald C. Petersen
William B. Hopf
Joseph Bruder Gary S. Robinson
Lowell G. Johnson
Richard Cox Frank Stone
Herman Koch
Bob Davis Malcolm V. Thaden
Joseph L. Koepfinger*
Julian Forster* Richard L. Townsend
David J. Law
Joe D. Watson
Joanna N. Guenin
Daleep C. Mohla
Mark S. Halpin Howard L. Wolfman
Paul Nikolich
T. W. Olsen
*Member Emeritus
Also included are the following nonvoting IEEE-SA Standards Board liaisons:
Satish K. Aggarwal, NRC Representative
Richard DeBlasio, DOE Representative
Alan Cookson, NIST Representative
Michelle D. Turner
IEEE Standards Project Editor
vi Copyright © 2005 IEEE. All rights reserved.

Contents
1. Overview. 1
1.1 Scope. 1
1.2 Purpose. 2
1.3 How to use this standard. 2
1.4 Organization of this standard. 6
2. Normative references. 6
3. Definitions and acronyms . 7
3.1 Definitions. 7
3.2 Acronyms. 10
4. General requirements. 10
4.1 Systems engineering process . 11
4.2 Policies and procedures for systems engineering . 11
4.3 Planning the technical effort . 12
4.4 Development strategies. 13
4.5 Modeling and prototyping. 13
4.6 Integrated repository . 13
4.7 Integrated data package. 14
4.8 Specification tree . 16
4.9 Drawing tree. 16
4.10 System breakdown structure. 17
4.11 Integration of the systems engineering effort . 17
4.12 Technical reviews . 19
4.13 Quality management . 19
4.14 Product and process improvement.19
5. Application of systems engineering throughout the system life cycle . 20
5.1 System definition stage. 21
5.2 Preliminary design stage. 25
5.3 Detailed design stage . 29
5.4 Fabrication, assembly, integration, and test stage. 32
5.5 Production and support stages . 34
5.6 Simultaneous engineering of life cycle processes . 36
6. The systems engineering process . 37
6.1 Requirements analysis . 37
6.2 Requirements validation . 43
6.3 Functional analysis. 45
6.4 Functional verification. 48
6.5 Synthesis . 49
6.6 Design verification. 53
6.7 Systems analysis . 57
6.8 Control . 61
Annex A (informative) The role of systems engineering within an enterprise. 67
Annex B (informative) The systems engineering management plan. 71
Annex C (informative) Use of IEEE Std 1220 in an ISO/IEC 15288:2002 context. 79
Annex D (informative) Bibliography. 87
viii Copyright © 2005 IEEE. All rights reserved.

IEEE Standard for Application and
Management of the Systems
Engineering Process
1. Overview
1.1 Scope
This standard defines the interdisciplinary tasks that are required throughout a system’s life cycle to
transform stakeholder needs, requirements, and constraints into a system solution. This standard is intended
to guide the development of systems for commercial, government, military, and space applications. The
information applies to a project within an enterprise that is responsible for developing a product design and
establishing the life cycle infrastructure needed to provide for life cycle sustainment.
This standard specifies the requirements for the systems engineering process (SEP) and its application
throughout the product life cycle. It does not attempt to define the implementation of each system life cycle
process, but addresses the issues associated with defining and establishing supportive life cycle processes
early and continuously throughout product development. In addition, the standard does not address the many
cultural or quality variables that should be considered for successful product development. The standard
focuses on the engineering activities necessary to guide product development while ensuring that the
product is properly designed to make it affordable to produce, own, operate, maintain, and eventually to
dispose of, without undue risk to health or the environment.
The requirements of this standard are applicable to new products as well as incremental enhancements to
existing products. It applies to one-of-a-kind products, such as a satellite, as well as products that are mass-
produced for the consumer marketplace. The requirements of this standard should be selectively applied for
each specific system-development project. The role of systems engineering within the enterprise
environment is described in Annex A.
The content of this standard describes an integrated approach to product development, which represents the
total technical effort for the following:
a) Understanding the environments and the related conditions in which the product may be utilized and
for which the product should be designed to accommodate
b) Defining product requirements in terms of functional and performance requirements, quality factors,
usability, producibility, supportability, safety, and environmental impacts
c) Defining the life cycle processes for manufacturing, test, distribution, support, training, and
disposal, which are necessary to provide life cycle support for products
IEEE
Std 1220-2005 IEEE STANDARD FOR APPLICATION AND MANAGEMENT
1.2 Purpose
The purpose of this document is to provide a standard for managing a system from initial concept through
development, operations, and disposal. The inclusion of computers and associated software in today’s
products has made the need to engineer each of those products as a total system more acute. The human,
physical, and software components should all be addressed to optimize overall system performance.
This standard, IEEE Std 1220-2005, may be used in conjunction with ISO/IEC 15288:2002 [B3]. This
standard generally prescribes more detailed systems engineering process and management requirements that
complete or complement the process activities described in ISO/IEC 15288:2002. However, ISO/IEC
15288:2002 provides additional process definition and guidance that supports life cycle model definition
and application of the systems engineering process across a system’s life cycle.
1.3 How to use this standard
1.3.1 Conformance
Normative provisions of this standard, which are indicated by a “shall” statement, are requirements to claim
conformance to this standard. Provisions that are indicated by a “should” statement are recommendations.
An enterprise that desires to claim conformance with this standard demonstrates conformance by defining
and implementing procedures for accomplishing all normative provisions.
1.3.2 Recommendations and tailoring
The enterprise should also incorporate select recommended and optional provisions into their procedures
and should ensure that each project within the enterprise complies with these procedures.
Clause 4 provides some normative provisions and recommendations for implementing systems engineering
within an enterprise or on a project. Normative provisions of Clause 4 include the development and
maintenance of enterprise policies and procedures. Enterprise policies and procedures that describe the
application of the systems engineering process (SEP) throughout a project life cycle typically provide the
basis for project-specific application of the enterprise’s SEP. Therefore, it is expected that an enterprise
would establish and maintain such policies and procedures.
Clause 6 defines the SEP, which is accomplished iteratively to define system products and life cycle
processes. Thus, the initial provision that defines each subprocess (requirements analysis, functional
analysis, etc.) includes a “shall” statement to ensure that an enterprise’s SEP addresses each subprocess and
the tasks for performance of that subprocess. The remaining subclauses, when specified within the definition
of a subprocess, are recommended to provide flexibility in adapting the subprocess and the task definitions
of the SEP for the purposes and typical system engineering efforts of the enterprise. Clause 6 describes the
recommended approach to project tailoring of the enterprise SEP, which would be applied for any particular
project iteration of the SEP as described in Clause 5.
The initial provision of Clause 5 contains a “shall” statement to ensure that the project addresses application
of the SEP throughout the system life cycle. The remaining provisions under Clause 5 describe
recommended and optional activities that a project commonly performs when applying the SEP during each
stage of a typical system life cycle. The recommended and optional activities of Clause 5 should be
considered by the project during tailoring of the enterprise SEP for any particular iteration of the SEP
throughout the system life cycle. This approach provides the project with the flexibility needed to address
different levels of system development and appropriate rigor of SEP application throughout various system
life cycle stages.
The numbers in brackets correspond to those of the bibliography in Annex D.
2 Copyright © 2005 IEEE. All rights reserved.

IEEE
OF THE SYSTEMS ENGINEERING PROCESS Std 1220-2005
1.3.3 System paradigm
The description of the SEP, and its application throughout the life cycle, demands the use of a system
paradigm to aid the presentation of this material. The terms used to support this paradigm are defined in
Clause 3. As enterprises and projects gain familiarity with the paradigm, they may substitute more familiar
terms that are applicable to their industry or business practices. The system paradigm is the foundation of
this standard and is described in the following subclauses to support the different uses of the term system.
On a large scale, there are biological systems, ecological systems, weather systems, solar systems, etc. Thus,
a system can be viewed as an element of a larger system, and the challenge is to understand the boundary of
the system, which is the focus of the development effort, and the relationships and interfaces between this
system and other systems. The focus of this standard is product-oriented systems such as the automobile, the
airplane, or information systems.
1.3.3.1 Hierarchy of system elements
A system is typically composed of related elements (subsystems and components) and their interfaces.
Additionally, elements include the people required to develop, produce, test, distribute, operate, support, or
dispose of the element’s products, or to train those people to accomplish their role within the system.
Figure 1 provides a hierarchy of names for the elements making up a system. This generic system hierarchy
is a key concept within this standard because it ties the system architectures, specification and drawing trees,
system breakdown structure (SBS), technical reviews, and configuration baselines together. Many elements
within the system hierarchy can be considered a “system” by the classical definition, but actually represent
subsystems within the system hierarchy. Likewise, the life cycle processes represent subsystems within the
overall system hierarchy.
Complex components represent system elements that are composed of hardware, software, and/or humans,
which are recognizable in terms of life cycle process (how to design, test, produce, support, etc., is known),
and the domain-specific engineering team assumes responsibility for the development of the complex
components. This is a judgment call—complex components may demand the rigors of the SEP or may be
well suited for component development teams.
Figure 1—Hierarchy of elements within a system
IEEE
Std 1220-2005 IEEE STANDARD FOR APPLICATION AND MANAGEMENT
The human elements are integral to the systems hierarchy and may be present at any level. The human
elements are not identified in the system hierarchy since the intent of the hierarchy is to identify the system
element for which the system is being defined, and the human/system integration issues should be addressed
in terms of the human’s role in operating, producing, supporting, etc.
The hierarchy of elements within a system is provided to illustrate that systems may be comprised of other
systems (subsystems), which represent complex elements for which no existing design solution or supplier
can be identified. The number of levels of subsystem or complex components is dependent on the
complexity of the system being developed. The SEP is applied at each level in the system hierarchy for
which the system element is a complex item for which no available design solution, or existing producer,
can be identified. Once a system element can be identified with a hardware, software, or human element, the
discipline-specific design methodologies are utilized to design the system element.
1.3.3.2 Building block structure
The basic building blocks of a system are depicted in Figure 2—the system, its related product(s), the life
cycle processes required to support the products, and the subsystems that make up the product(s). Each life
cycle process—development, manufacturing, test, distribution, operation, support, training, or disposal—is
itself like a system in that products should be developed to fulfill the purpose of the life cycle process. For
example, a product should be manufactured. Manufacturing is a life cycle process. The products associated
with the manufacturing life cycle process include special equipment, tools, facilities, and production
processes and procedures. The products that make up life cycle processes may also require life cycle
sustainment in that they may be required to be developed, tested, manufactured, distributed, operated,
supported, trained, and disposed of.
Figure 2—Basic building blocks of a system
1.3.3.3 Product and life cycle process definition
Figure 3 depicts the life cycle processes, eight essential functional processes that may be necessary to
provide total consumer satisfaction and meet public acceptance. Once the need for a life cycle process is
identified, the life cycle process is treated as a system, and the SEP is applied to define, design, and establish
the life cycle process and the supporting products and processes, to maintain the life cycle process in an
operational condition.
a) Development. The planning and execution of system and subsystem definition tasks required to
evolve the system from stakeholder needs to product solutions and their life cycle processes.
4 Copyright © 2005 IEEE. All rights reserved.

IEEE
OF THE SYSTEMS ENGINEERING PROCESS Std 1220-2005
b) Manufacturing. The tasks, actions, and activities for fabrication and assembly of engineering test
models and brass-boards, prototypes, and production of product solutions and their life cycle pro-
cess products.
c) Test
1) The tasks, actions, and activities for planning for evaluation and conducting evaluation of syn-
thesis products against the functional architecture or requirements baseline, or the functional
architecture against the requirements baseline.
2) The tasks, actions, and activities for evaluating the product solutions and their life cycle pro-
cesses to measure specification conformance or stakeholder satisfaction.
d) Distribution. The tasks, actions, and activities to initially transport, deliver, assemble, install, test,
and check out products to effect proper transition to users, operators, or consumers.
e) Operations. The tasks, actions, and activities that are associated with the use of the product or a life
cycle process.
f) Support. The tasks, actions, and activities to provide supply, maintenance, and support material and
facility management for sustaining operations.
g) Training. The measurable tasks, actions, and activities (including instruction and applied exercises)
required to achieve and maintain the knowledge, skills, and abilities necessary to efficiently and
effectively perform operations, support, and disposal throughout the system life cycle. Training is
inclusive of the tools, devices, techniques, procedures, and materials developed and employed to
provide training for all required tasks.
h) Disposal. The tasks, actions, and activities to ensure that disposal or recycling of destroyed or irrep-
arable consumer and life cycle processes and by-products comply with applicable environmental
regulations and directives.
A typical system is composed of products developed by the enterprise or by suppliers/subcontractors. Each
supplier/subcontractor considers its product as part of its system. The organization that purchases these
products for integration into a higher-level system should refer to these products as subcomponents,
components, complex components, or subsystems, depending on the significance of the element in
contributing to the system’s performance, functionality, and costs.
Figure 3—Life cycle process definition
IEEE
Std 1220-2005 IEEE STANDARD FOR APPLICATION AND MANAGEMENT
The design of the products and life cycle processes should consider the human as an element of the system
in terms of operators, maintainers, manufacturing personnel, training personnel, etc., for the purpose of
understanding the human/system integration issues and ensuring that the system products are producible,
maintainable, and usable, and that the system processes are effectively established to ensure production
quality levels and reduce overall ownership cost. Thus, Figure 3 depicts the human elements associated with
the system products and processes. The operational process addresses the operation of the product(s) and
aids in the identification of operational procedures and human cognitive and anthropomorphic
considerations necessary to ensure system usability.
The definitions of system elements are generated by activities of the SEP. This process is described in detail
in Clause 6. The SEP is used during each level of development to structure systems engineering activities
that identify technical requirements and desired system behaviors, and synthesize the system design.
1.4 Organization of this standard
— Clause 1 provides the scope, purpose, and organization of this standard.
— Clause 2 provides the normative references applicable to this document.
— Clause 3 establishes the meaning of terms and acronyms, as used in this standard.
— Clause 4 establishes requirements for planning and implementing an effective systems engineering
capability within an enterprise.
— Clause 5 provides a description of the application of the SEP through system definition, subsystem
definition, production, and support.
— Clause 6 provides the detailed tasks of the SEP to be tailored and performed to develop product solu-
tions and their supporting life cycle processes.
— Annex A discusses the SEP as the total technical effort responsible for establishing the product
design and life cycle support products within an enterprise.
— Annex B provides a template to help an enterprise prepare a systems engineering management plan.
— Annex C discusses some of the key differences between IEEE Std 1220 and ISO/IEC 15288:2002
[B3].
— Annex D provides bibliographic references.
2. Normative references
The following referenced documents are indispensable for the application of this standard. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendmen
...