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Policy Statement 518 - Unified Definitions for Critical Infrastructure Resilience


Approved by the Committee on Critical Infrastructure on August 7, 2013

Approved by the Public Policy Committee on August 14, 2013

Adopted by the Board of Direction on October 8, 2013.


The American Society of Civil Engineers (ASCE) supports a unified set of definitions for the concepts of critical infrastructure, hazards, multihazards, and resilience as follows:

  • Critical infrastructure includes systems, facilities, and assets so vital that their destruction or incapacitation would have a debilitating impact on national security, the economy or public health, safety, and welfare.  Critical infrastructure may cross political boundaries and may be built (such as structural, energy, water, transportation, and communication systems), natural (such as surface or ground water resources), or virtual (such as cyber, electronic data, and information systems).
  • All-hazards include events and conditions such as infrastructure deterioration, natural disasters, accidents, and malevolent acts that have the potential to cause injury, illness, death, damage or disruption of services.
  • Multihazards denote the relevant environmental or manmade conditions that are used for engineering analysis and design.  A sound multihazard approach to engineering practice will provide infrastructure resilience to all-hazards risks.
  • Resilience refers to the capability to mitigate against significant all-hazards risks and incidents and to expeditiously recover and reconstitute critical services with minimum damage to public safety and health, the economy, and national security.


In the post 9/11 environment, there have been various definitions of critical infrastructure, all-hazards, multihazards, and resilience.  Without unified definitions, it is difficult to develop industry and building standards and useful metrics for progress in this vital area.  


As an individual member professional organization representing practitioners in the public and private sectors, as well as educators, ASCE is uniquely qualified to provide definitions which can be used to clarify the discussion in government and the infrastructure industry at large.  An all-hazards approach is used in the government and emergency management communities, while the engineering community uses a multihazards approach to address infrastructure resilience.  It is important to recognize and define the context for both approaches.  These baseline definitions will aid in the development of standards and federal, regional, state and local legislation and regulation.

ASCE Policy Statement 518
First Approved in 2006