Applied Safety Science and Engineering Techniques (ASSET™)

The Evolution of Hazard Based Safety Engineering into the Framework of a Safety Management Process

Applied Safety Science and Engineering Techniques (ASSET) merge hazard based safety engineering and safety science principles in an overall framework of a safety management process to achieve, maintain and continuously improve safety. The ASSET process has been synthesized from current, industry-standard risk assessment and risk management guidelines, including recent ISO, IEC and ANSI publications.

Basic relationships are explored among hazards, exposure and harm to persons, property and the environment. Various potential approaches to protect against harm are then explored in the framework of safety management, systems engineering, quality management systems, concurrent engineering, human factors and other relevant principles.

This ASSET Safety Management process has potential application in virtually any industry and product segment to support informed decisions on solutions to difficult safety issues, using sound safety science and engineering experience and judgment. This article for the 2011 IEEE PSES symposium covers the ASSET safety management process, its guiding principles and objectives.


The objective of the ASSET Process of Safety Management is to utilize Applied Safety Science and Engineering Techniques (ASSET™), together with existing standards, codes and regulations, to achieve, maintain and continuously improve the safety of products, processes and services for safer living and working environments. ASSET™ (Applied Safety Science and Engineering Techniques) is a trademark of Underwriters Laboratories Inc.


This article follows the introductory article Applied Safety Science and Engineering Techniques (ASSET™): Taking HBSE to the Next Level (In Compliance, Novmber 2012) which was presented at the 2010 ISPCE of the IEEE Product Safety Engineering Society, and had established the case and set the stage for ASSET.

A similar article was published by the American Society of Safety Engineers in their SH&E (Safety Health and Environment) Standards Digest, a publication of their Engineering Practice Specialty. ASSET also reflects concepts of the ANSI/ASSE Z690 series, the US national adoption of ISO 31000, ISO/IEC 31010 and ISO Guide 73, initiating membership on the ISO TAG on Risk Management.

Certain ASSET principles have been applied and presented in recent conferences including the 2009 NASA Aerospace Battery Workshop (“FTA {Fault Tree Analysis}/FMEA {Failure Modes and Effects Analysis} Safety Analysis Model for Lithium-ion Batteries”), ASEAN/ ACCSQ 2010 (“ASEAN­US Enhanced Partnership Workshop on Hazard-Based Engineering Principles for the Electrical and Electronic Equipment: A Risk-Based Approach Applied to Li-Ion Battery (LIB) Hazards”), as well as ICPHSO 2011 (International Consumer Product Health and Safety Organization, “Hazard Analysis: Hazard Based Safety Engineering & Fault Tree Analysis”). The ASSET Safety Management process will also be presented for the IEEE and Argonne National Lab, 2011 Today’s Engineering Challenges – Tomorrow’s Solutions Technical Conference and Exhibition, November in Chicago.

With essential technical input and development of Bob Davidson and strategic leadership of Dan Bejnarowicz, ASSET was developed in the safety management process framework. Notification has just been made that this ASSET work has earned a 2011 IEEE Region 1 Award (Northeastern US) in the category of “Technological Innovation (Industry or Government): For significant Patents, for discovery of new devices, development of applications or exemplary contributions to industry or government.”

ASSET is now the subject of a 2-day workshop to put your skills to the test by applying ASSET analysis to example products and prepare to address difficult safety issues using a multi-disciplined, team-oriented approach, supported by science as well as your own experience and judgment.


The ASSET process has application in areas including the development of safety standards, codes, and regulations, and the design, evaluation, compliance, certification and safety management of products, processes and services. As such, ASSET applies to functions and responsibilities including safety designers, regulatory compliance, product safety certifiers, standards/codes developers and product and program safety managers. ASSET can also help to integrate and address the needs of various stakeholders including regulators, AHJs, standards developers, trade and professional organizations, consumer groups, government agencies and the public.

For example, relevant safety requirements are generally determined by first establishing the scope of the product, process, or service in question. This scope is then compared to the scope of identified standards, codes and/or regulations that may potentially apply. The scope and context of the assessment itself is also established, including boundaries, and scope alignment on all three counts is sought. In this early stage and throughout the process, potential gaps need to be identified and bridged. A gap may exist for example, if a product, process or service – in the context of its application – does not fall completely within the scope of existing safety standards. Another gap may exist whereby a product, process or service falls within the scope of a safety standard, but involves features, functions, technologies or applications that may (a) introduce a safety hazard, and (b) not be anticipated or addressed by the requirements in the standard.


ASSET provides a process and methodology for (a) complementing existing standards in evaluating the safety of products, processes or services, (b) assisting in the evaluation of products, processes or services not within the scope of existing standards, (c) evaluating product features (materials, constructions), functions, technologies or applications not anticipated or covered by existing standards. In these situations, ASSET can be applied to (1) help identify hazards not anticipated or covered by existing standards and the need for additional requirements to meet the safety objective (intent) of the standards, and (2) help identify alternative protective measures not anticipated by the standard but which can achieve an equivalent level of safety to the protective measures specified in the standard, thereby meeting the safety objective (intent) of the standard.

In fact, the ASSET process stages include repeated “spec­checks”, whereby the initially identified requirements are assessed at each stage.


The ASSET process of safety management was developed as the evolution of hazard-based safety engineering principles and safety science into an overall framework of a safety management process. Hazard Based Safety Engineering (HBSE) was originally conceived by HP/Agilent, and targeted typical types of hazards and forms of injury involving electronics products, such as information technology and office equipment.

The ASSET process is based on a number of acknowledged risk management/risk assessment principles and processes, for example those found in publications including but not limited to ISO/IEC Guide 51, IEC Guide 116, ISO 31000, ISO/IEC 31010, ISO 14121, ISO 14971, IEC 60300-3-9 and ANSI/ASSE Z690.

Figure 1: ASSET Process of Safety Management

This process involves stages to (a) formulate the right types of questions to identify the scope of the product, system or service to be evaluated for potential harm, (b) identify and analyze hazards (potential sources of harm), (c) identify, analyze and evaluate protective measures to reduce the risk of harm (e.g., risk of injury from products), (d) assist in the determination of whether or not an acceptable level of safety is achieved, (e) understand and apply methods to maintain and continuously improve safety. This can help explain, apply and enhance existing requirements, and help address emerging technologies, products and applications.

This ASSET process was developed to address a broad spectrum of applications, and each stage has different needs and significance for the assessment of different products, processes, services in different applications. The following provides a brief look at each ASSET process stage and its objectives.

Determine Scope/Context
The goals of this stage are to determine and attempt to align the scope and context of the following: the product, process or service to be assessed, the assessment itself and the initially identified requirements. Relevant topics include (a) the subject of the assessment, including systems aspects of materials, components, subsystems, environment and boundaries with interfaces and interactions, (b) intended implementation, operation, use, users and others affected (c) conditions and requirements for installation, (d) recommended procedures for maintenance and repair, (e) potential effects of packing, shipping and storage, (f) reasonably foreseeable misuse (using a sub-process developed to determine degrees of reasonable foreseeable misuse and associated guidance) , (g) other conditions or factors of potential impact, and (h) applicable standards, codes and/or regulations.

Identify/Analyze Hazards
The goals of the stage are to (a) identify potential types and sources of harm (hazards), (b) determine how harm can occur (hazardous situations, hazardous and harmful events) and the severity of the harm, (c) sort consequences by the level of severity (initial consequence evaluation akin to worst case scenario, with guidance on severity factors, and consideration of extent and exposure of harm), and (d) determine if the applicable standards, codes and/or regulations address the identified hazards, or if there are gaps that need to be addressed.

Specify/Identify/Design Protective Measures
In this stage, protective measures are specified, identified or designed, depending on the given function and responsibility being fulfilled. For example, a protective measure may be specified by developers of standards, codes and regulations, designed by a manufacturer or identified by an evaluator. This stage has goals to (a) establish the safety objective(s), (b) determine the need for protective measures, (c) identify the potential protective measure strategies, categories and mechanisms, (d) analyze and prioritize protective measures, and (e) specify, design and implement the protective measures.

Evaluate Protective Measures
The goal of this stage is to determine whether protective measures are adequate and effective by (a) evaluating whether and how protective measures meet specific safety objectives, (b) identifying safety attributes that are being relied upon and need to be controlled, and (c) evaluating those safety attributes. In order to determine if the goal of this stage is achieved, key questions are asked which include the following:

  • Have all the hazards been identified?
  • Have the safety (risk reduction) objectives been determined?
  • Have the protective measures intended to address the hazards and achieve the safety objectives been identified and designed?
  • Have tests and evaluations been conducted to demonstrate that the protective measures are capable of achieving the safety objectives with acceptable results?
  • Have the constructions, components and materials that are relied upon for the protective measure to meet the safety objectives been identified?
  • Have their safety-related characteristics (safety attributes), factors which may degrade those characteristics, and the tests and evaluations needed to determine their adequacy been identified?
  • Have the necessary evaluations/tests been performed with acceptable results?

Through this point in the ASSET process, these stages generally involve activities such as hazard based safety engineering, safety research, safety design, conformity assessment and new standards development. It is also noted that the evaluation of certain protective measures, including life safety devices, may effectively begin at this stage.

Decision Gate: Acceptable Level of Safety Achieved?
There are two basic outcomes of this safety decision. If it is determined that an acceptable level of safety has been achieved, then there is a need to control, monitor and review to maintain safety. However, if an acceptable level of safety has not been achieved, there is a different need to assess and decide on action. This may involve revisiting earlier process stages or discontinuing.

This point of the ASSET process generally involves conformance and compliance activities.

Control/Monitor/Review to Maintain Safety
At this stage, if determined that an acceptable level of safety has been achieved, the goal is to ensure that safety is then maintained by (a) establishing controls throughout the life cycle, up the supply chain, to ensure that safety is maintained, (b) monitoring field performance down the supply chain and factors that may impact safety by means of surveillance and follow up, and (c) periodically reviewing and assessing results and deciding on appropriate actions.

Decision Gate: Present Level of Safety Maintained?
Similar to the prior decision gate, there are also two basic outcomes of this safety decision. If determined that the present level of safety is being maintained, then there is a need to continue to control, monitor, and review. However, if the present level of safety is not being maintained, there is a different need to assess and decide on action. Again, this may involve revisiting earlier process stages or discontinuing.
This point of the ASSET process generally involves activities including certification, market and conformity surveillance, follow-up for certification mark integrity, updates in regulations, standards and codes, and assessment of new/emerging technologies that may either benefit or threaten safety.

Identify Opportunities for Improvement
The goal of this stage is to monitor and identify the opportunity, or the need, for improvement in (a) safety and safety standards and (b) the processes, methods and tools used to determine whether and how safety is achieved and maintained. These opportunities are then assessed to decide on action, which may involve revisiting earlier process stages.
Activities involved in this stage of the ASSET process include improvements in regulations, standards and codes, as well as improvements in safety assessment processes, methods and tools.


The stated objective of the ASSET Process of Safety Management is to utilize Applied Safety Science and Engineering Techniques (ASSET™), together with existing standards, codes and regulations, to achieve, maintain and continuously improve the safety of products, processes and services for safer living and working environments.

By this we mean to a) achieve an acceptable level of safety (once determined, based on specific safety objectives), b) maintain that present level of safety (throughout the entire lifecycle of the product, process or service, under all anticipated conditions, considering upstream (suppliers) and downstream (users and all affected) the supply chain), and c) continually seek and assess opportunities for improvement (based on the availability, need or demand for improvements).

ASSET stresses the importance of assessing the sources, causes and conditions of harm (as did HBSE before it), as well as the risk of harm (severity, likelihood, extent, exposure). ASSET also addresses different forms of potential harm to various entities, including persons (injury or health risk), property, the environment and even continuity of critical operations and functions. Sources are categorized in terms of energy or matter/substance that may be harmful, from different sources in various forms, conversions or conditions. The standard HBSE tools (3-block energy transfer model for injury, HBSE process to evaluate a safeguard and standard injury fault tree) are adapted and expanded.

Then the most effective protective measure strategies can be determined, with appropriate identification, evaluation and control of safety attributes – the very properties and characteristics of protective measures relied upon to achieve, maintain and improve this level of safety.

The ASSET process supports informed decisions using the best available information, data and other resources, based on the best available knowledge and experience, at progressive stages of development. This can help identify the degree of confidence in the decision and the relative need and value of additional inputs or analysis. ASSET can also serve as a tool for effective communication and interaction to share information, as needed by various stakeholders.



The author wishes to acknowledge the indispensable technical and strategic contributions of Robert J. Davidson, Jr. and Daniel E. Bejnarowicz of UL University.


  1. Risk management – Principles and guidelines, ISO 31000, First edition, 2009-11-15
  2. Risk management – Risk assessment techniques, IEC ISO 31010, Edition 1.0, 2009-11
  3. Risk management – Vocabulary, ISO Guide 73, First Edition, 2009
  4. Risk Management Series: ANSI/ASSE Z690.1-2011 Vocabulary for Risk Management (identical national adoption of ISO Guide 73:2009); ANSI/ASSE Z690.2-2011 Risk Management -Principles and Guidelines (identical national adoption of ISO 31000:2009); ANSI/ASSE Z690.3­2011 Risk Assessment Techniques (identical national adoption of ISO/IEC 31010:2009)
  5. Safety aspects, Guidelines for their inclusion in standards, ISO IEC Guide 51, Second edition, 1999
  6. Guidelines for safety related risk assessment and risk reduction for low voltage equipment, IEC Guide 116, Edition 1.0, 2010-08
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  8. Hazard Based Safety Engineering (HBSE) UL Supplement, Underwriters Laboratories Inc., 2003
  9. Risk Assessment Guidelines for Consumer Products, Official Journal of the European Union: OJ L22 Vol 53, 26 January 2010, Part IV, Appendix 5
  10. Dependability Management, Part 3 Application Guide – Section 9 Risk Analysis of Technological Systems, IEC 60300-3-9, First Edition
  11. Safety of machinery – Risk assessment – Part 1: Principles, ISO 14121­1:2007
  12. Medical devices – Application of risk management to medical devices, EN ISO 14971
  13. W. Hammer, Product Safety Management and Engineering, 2nd ed, 1993
  14. Fault Tree Handbook, NUREG-0492, Nuclear Regulatory Commission, Washington D.C., 1981
  15. Fault Tree Handbook with Aerospace Applications, NASA, Washington D.C., 2002
  16. Potential Failure Mode and Effects Analysis in Design (Design FMEA), SAE J1739, 2009

© 2011 IEEE. Reprinted, with permission, from the proceedings of the 2011 IEEE International Symposium on Product Compliance Engineering.
© 2012 UL LLC.  All rights reserved. This document may not be reproduced or distributed without authorization.

ASSET is trademark of UL LLC
ASSET and HBSE workshops are available through UL.

Thomas Lanzisero
is a Sr. Research Engineer and Distinguished Member of Technical Staff at UL LLC (Underwriters Laboratories, Melville, NY) with nearly 30 years of applied practice in safety engineering. He is a registered Professional Engineer (P.E.) and principal instructor and practitioner of Hazard Based Safety Engineering (HBSE). He has led development of Applied Safety Science and Engineering Techniques (ASSET™), including the ASSET Safety Management Process for informed decisions to achieve, maintain and continuously improve safety as a design objective. This work has recently been recognized with a 2011 IEEE Region 1 Award for Technological Innovation.

This and related hazard analysis and risk assessment work has been extensively published and presented, including keynote presentation on the safety of consumer electronics into the future at the 2012 International Conference on Consumer Electronics (ICCE) by the IEEE CES, 2012 Advanced Product Safety Management course at St. Louis University, 2010 and 2011 International Symposium on Product Compliance Engineering by the IEEE Product Safety Engineering Society, 2011 IEEE Chicago Argonne National Laboratories Technical Conference, International Consumer Product Health and Safety Organization (ICPHSO 2011), Association of Southeast Asian Nations (ASEAN), Asia Pacific Economic Cooperation – Joint Regulatory Advisory Council (APEC JRAC Risk Assessment Workshop), American Society of Safety Engineers (ASSE) and NASA (2009 NASA Aerospace Battery Workshop).

An IEEE Senior Member, Tom is Founding Chair of the Long Island, NY Chapter of the IEEE Product Safety Engineering Society (PSES) and Vice Chair of the IEEE Risk Assessment Technical Committee (RATC). He serves as technical expert in committees for electric shock protection and risk management, including US National Committee Technical Advisory Groups (USNC TAGs), the International Electrotechnical Commission (IEC TC64 MT4) and the International Organization for Standardization (ISO 31000 / ANSI Z690). He can be contacted at +1.631.546.2464 or