Figure 1. An All Weather Lifeboat owned and operated by the Royal National Lifeboat Institute in England. Photo: Alex Wilson

by Russ Derickson, Ph.D., P.E., ENV SP

Introduction

This blog is about lifelines, which are at the heart of sustainability. Lifeline is a term that appears often in publications and conversations in broad settings. In original usage, a lifeline is a rope—a literal “line”—thrown by an able-bodied seaman to rescue an overboard sailor from drowning in a stormy sea. In time, the meaning evolved as a metaphor to describe a means of support or rescue in any difficult or challenging situation. The word lifeline has found prolific and impactful use in multiple domains of enterprise such as the insurance industry and various health and safety programs available to the public.

More recently the term lifeline has become common in discussions of resilience and sustainability. I submit that a lifeline is any mechanism, process, or tool that provides resources to sustain and ensure safety for some essential function, and thus is aligned with the definition of sustainability. In its essence, therefore, a lifeline is a composite that comprises a resource and a linkage to serve a vital need (Fig. 2). One can think of a lifeline as a form of supply chain with a fully integrated structure. Resources may be power and shelter, knowledge and skill, social services, food and water, medical supplies and equipment, and so forth. Links take various forms.

Figure 2. A lifeline consists of a resource and link to a vital need. Image: Russ Derickson

But there is more. In a previous blog, I clarified the meaning of sustainability to be “enduring function,” served by resilience in analogy to the immune system that serves the health and wellness of its human host. Thus, lifelines that are resilient—specifically, systems of interacting resilient lifelines—operate to ensure the enduring function and safety of critical elements of society’s numerous enterprises.

FEMA operates within a community-based system of interacting, interdependent lifelines needed to serve the safety, health, and well-being of society in preparation for and response to emergencies. FEMA views lifelines on a macro level, generally with wide spatial distribution. It is also important to address lifelines on the micro level at more local scales to complement the role of FEMA. A fundamental theme with FEMA is continuity of critical functions in a disaster. In concert with this theme are frameworks and processes to minimize recovery time for compromised facilities, in which there is a hierarchy of importance that depends on the criticality of the facility affected. For instance, hospitals, food markets, and certain social services generally take precedence over a recreational center, library, or clothing store in recovery efforts and timing.

The seven basic elements of the FEMA system are shown in Fig. 3. The graphic of lifelines includes hazardous materials and waste that FEMA monitors to protect citizens. Implicit in the figure is that every element of the lifeline system contains resources and links to vital societal needs. To expand on what was previously introduced, resources include skills and knowledge that are embodied in human capital and knowledge archived in comprehensive databases. Also, there is interdependence. Health and medical rely on transportation and power. Transportation relies on power and fuel, and so forth.

Figure 3. System of community-based lifelines protected by FEMA. Image: FEMA

A major point needs to be reinforced and pondered as we venture forth into lifelines and their indispensable role in sustaining society’s essential functions. As depicted in Figure 1, lifelines are a combination of a resource and a link. However, some publications have characterized lifelines solely as links, omitting the resource factor. This is an incomplete, limiting perspective. In my view, a linkage with no resource to deliver is a broken lifeline. Likewise, a resource with no linkage is a broken lifeline. As obvious as these statements are, this message can be lost, with bad consequences. A broken lifeline is a sad story we have all heard or directly experienced at certain times in our respective lives. Central to resilient design are robust, intact lifelines.

Figure 4. Schematic of a simple system of lifelines delivering renewable resources to an essential societal function. Note the two lifelines in series, a lifeline with a broken link, and a lifeline with an intact link and no resource. Image: Russ Derickson

Fig. 4 is a schematic of a simple system of lifelines. Shown are two lifelines in series, two in parallel, and two broken. The schematic is far from exhaustive in possible lifeline configurations. One lifeline has a broken link to available resources, another has an intact link but with unavailability of resources. Most lifelines are inherently connected in some manner and interdependent to various degrees. Additionally, they often feed multiple essential functions. A single power facility in a community, for example, may power industrial processes; lighting, cooling, and heating to buildings; and operation of medical devices. One could argue that reliance on a single source is innately not a resilient strategy. To reiterate, lifelines need to be resilient and linked to renewable resources to ensure sustainability.

The fundamental lifeline on Earth is photosynthesis, powered by the sun, and is the origin of nutrients linked to virtually all living creatures and plants. Nature’s web of lifelines and composite resiliency spring from that original source. Sustainability and the mechanisms of resiliency that support it necessarily must all feed from a renewable trough of resources in their “metabolic” processes. This is true in nature and needs to be true in the world of humans where it seriously falls short. Therein lies the human charge.

The full story of lifelines can become quite expansive. This blog limits discussion of lifelines to a constrained scope of societal functions in the built environment, such as transportation and energy networks; communication and information technology systems; health and medical provision; retail and food markets; and infrastructure for housing and commerce. The primary focus will be on healthcare provided by hospitals, which represent the upper end of lifeline complexity. From a structural and operational perspective, Peter Drucker referred to hospitals as “… the most complex form of human organization we have ever attempted to manage.”

Anatomy of Lifelines

Lifelines, which typically contain many integrated working systems and parts, encompass vast ranges in trait, scale, role, complexity, and dependency. They vary in hierarchy of importance and level of vulnerability to assaults. Most importantly, a lifeline should be structured with resilience that contains both preventive and curative features (i.e., “preventative” mitigation and “curative” rescue and recovery). Additionally, with more frequent and intensifying climate-related assaults and their inherent statistical non-stationarity (which means the usual way of analysis is ineffective), lifeline resilience should be highly adaptive in nature, a strategy that takes on some intriguing dimensions with room for expansive creativity.

An instructive example of a lifeline is the provision of water to buildings. Provisioning entails a reliable source or water, conduits, pumps, and control devices. A flowing water system relies on gravity feed and electricity for pumps to both replenish supply tanks and supplement flow to end-uses. The lifeline of transmitted electricity requires power generation and wires for delivery. In this simple case, water and electricity coordinate interdependently as companion lifelines, in which provision of water is dependent on electricity, and electricity may be dependent on water for the cooling of power generation facilities. Or through hydro power, water may be the means to generate electricity.  Sometimes the link is one-way, such as with machinery that is dependent on an electrical lifeline, but not the converse. Examples of dependency versus interdependency with lifelines are myriad and too immense to list exhaustively.

As prefaced above, lifelines perform mostly within systems of multiple, interactive, interdependent lifelines. Lifeline systems can be quite complex. Lifelines are structured in series, parallel, or in both manners in intricate ways as suggested in Fig. 3. To achieve resiliency, lifelines require backup to various degrees and proportions. A basic suite of lifelines is continuously operative for any given essential function − in times of both normality and stress − in which additional planned resources and measures are brought online according to threat and risk. Consequently, interventions such as shuttered windows, mobile flood barriers, on-alert services, backup power, and stashed supplies are crucial in times of various stresses and assaults.

Two key themes for resiliency are redundancy and safe-to-fail designs introduced in my previous blog on resilience. A Safe-to-fail approach to design and operation, though known about for decades in certain circles, has only recently begun to emerge in applications that promise to bolster society’s functions and safety in the face of mounting climate-related assaults. We explore safe-to-fail design subsequently.

Figure 5. A life ring in the port of Rivedoux-Plage, Ré Island, Charente Maritime, France. Photo: Wikimedia Commons

The Essence and Role of Lifecycles and Innovation Cycles in Lifelines

At this point in our exploration of lifelines, it is illuminating to cast an eye to their lifecycles and innovation cycles. Everything on Earth has an existence bounded by a lifecycle. In my previous blog I characterized sustainability as the sustain pedal on a piano in which “…. the sustain pedal commands a hierarchy of timelines for various animate and inanimate elements and objects on Earth.” Cities outlive buildings and bridges, which outlive people, but the sustainability (i.e.,“enduring function”) of the lifelines of shelter and transportation, for example, are not intrinsically tied to the lifecycle of individual edifices, systems, and components. Both shelter and the elements that comprise a transportation network, and all other societal lifelines and their sub-assemblies, as well, are replaced with innovative or refurbished versions as time progresses and various lifecycles reach an end point. However, we certainly seek to extend the lifecycles of current lifelines through maintenance and use of renewable materials and to do so resiliently.

Advances in technology and know-how serve to yield improvement in the ways we achieve our overarching goal of resilience with lifelines and their lifecycles for our essential functions in society. Thus, in adding to and emphasizing what was stated previously, we need to look judiciously at the role and criticality of our various societal functions and establish appropriate lifelines, lifecycles, and innovations in our efforts. These efforts require an eye to the future with rigorous and savvy conception, planning, design, and engineering; economic prudence; attention to critical trade-offs; and inclusion of comprehensive stakeholder voices.

Safe-to-Fail Path to Resilience and Sustainability

Safe-to-fail design differs fundamentally from the traditional fail-safe approach. Fail-safe, which denotes total safety from failure, is predicated on presumed knowledge of the greatest threats to a given design, and entails rigorous analysis around the known extremes. The reality is that past history and data on extremes have limited relevance to future possibilities as climate change produces events that are more frequent and intense.

Safe-to-fail design acknowledges the likelihood, if not certainty, of failure and allows functions to continue, but perhaps temporarily at a lesser state of performance, if failure occurs. Potential for failure increases with more frequent and intense storms. But a safe-to-fail protocol tends to prevent catastrophe. On the other hand, fail-safe design, fatefully, can lead to a false sense of security and result in catastrophe when design limits and “safety factors” are inadvertently exceeded. Response then becomes monumentally overtaxed, often with inadequate tools. We experienced this type of calamity with levee failure in Hurricane Katrina in August of 2005. Another classic case of fail-safe design that failed catastrophically was the sinking of the Titanic in April of 1912, despite its design to handle accidental leaks. There are many other examples.

Predominant features of safe-to-fail design include modularity, multi-functionality, and redundancy; attention to key interactions with other lifelines and systems to minimize cascading failures through effective design; decentralization of control for better autonomy of performance; keen attention to adaptability to various types of assaults; and vital inclusion of stakeholder perspectives and needs to best serve everyone’s needs and minimize social inequity. In fairness, some of these attributes are present in fail-safe designs.

There is another, often unknown or under-appreciated, factor at play that leads to failure. There are vast numbers of unknown or unknowable events and factors with low probability of occurrence lurking invisibly and silently all around us. We have all heard about “fluke,” inconceivable events that catch us in total surprise such as the “rogue wave” or the random particle of dust on a printed circuit board. Individually, they impose a miniscule possibility of occurrence. Collectively, however, the laws of probability dictate that at least one of the vast multitudes of unseen low probability events is virtually certain to occur at some point in time. Designing for fluke accidents with a safe-to-fail approach may well save the day when one hits.

The hidden threat of multitudes of lurking, very low-probability dangers in which one is certain to suddenly pounce is a hard concept to grasp, thus has evaded awareness in many quarters of society. In principle, the safe-to-fail strategy for design deals effectively with such blindsiding invasions, but can be hard to achieve in practice. However, our current muddling attempts are improving. Safe-to-fail designs entail, among other facets, interwoven components and systems with clever redundancy, often with either cheap, quick and easy to replace components or especially robust ones, depending on nuance of application and criticality of role. Aircraft, for example, generally require greater robustness and redundancy than do ground vehicles. For augmented explanation, the reader is encouraged to read the chapter on resilience in Brittle Power (1982) by Amory and Hunter Lovins, which provides a remarkable treatise on the “science of resilience” and elucidates a viable path to safe-to-fail design.

In our quest for prudence and guiding sensibility, however, featuring and stressing safe-to-fail over fail-safe design must not be too strict and inflexible in stance. In truth, there are times when one approach may be superior to the other. In many cases a hybrid approach that combines both fail-safe and safe-to-fail design features makes most sense. In our processes of design, we have to sort through numerous confusing factors that direct and constrain our actions. In large part, optimal solutions are seldom, if ever, possible. We are nearly always compelled to make compromises and trade-offs, as discussed later.

Essential Societal Functions of Varying Complexity

Hospitals as a Guiding Model for Resilient Lifelines

As a major point of focus, it is instructive to look at medical facilities of varying scales as a powerful, guiding model for exploring and understanding critical operations that possess highly complex lifeline networks. As previously mentioned, compared to a majority of facility types, hospitals are at the highest end of complexity. The immense number of interactive services and systems required for dealing with vast-ranging types of morbidity and the omnipresent risk to life from disease or injury places hospitals in a class of their own. Hospital complexity can translate to great vulnerability to threats and disruptions, which demands heightened attention to resilient design and operation. Stand-alone emergency centers and urgent care facilities are less complex, but face similar threats and risks, typically to a far less extent.

A community or regional hospital requires transport of patients and staff; qualified staff of diverse knowledge and skill; drugs, medical supplies, and equipment; sources of power and water; communication and IT networks; food supply and service; and beds for patients. Each of these represents a resource or linkage in a lifeline. As with nearly all systems of lifelines, some lifeline linkages and resources operate in parallel, others in series, or sometimes both ways. Some are independent, while others are interdependent. Several require supply chains dependent on transportation and communication networks. Most require power and high-skilled human efforts. Artificial intelligence, automation, smart sensor technology, and fault detection, enabled by intricate software systems, are becoming more and more crucial for efficient, safe operation. AI assists with diagnostics, processes patient status and needs, manages supply chains, and provides decision tools and predictive analytics for operational accuracy and efficiency. Improved treatment of infant birth and care owes a lot to advances in emerging AI applications. Thwarting infant kidnappings with sensors and AI is another example.

A critical distinction to make is that the hospital building itself and its internal systems and components are not complete and functioning within themselves. The healthcare provided within the hospital indeed requires the physical infrastructure, but cannot operate without the external resources and linkages listed above. However, the hospital physical infrastructure indeed must be resilient. In the final analysis, the essential functioning of the hospital is reliant on the critical external lifelines that provide the necessary resources for operation. The same can be said of other facilities such as residential and commercial buildings, power plants, and grocery stores. In each case, the physical building and its functioning components are indispensable, but cannot operate without external lifeline support. In some cases, redundancy and backup supplies can deal temporarily with emergencies and disasters when external lifelines are broken, but with hospitals there are circumstances when the transport of patients, staff, and medical supplies is catastrophically thwarted when a break occurs.

A paramount reality that must be confronted is that if there is a fracture or impediment in any one of its external lifelines, the hospital will slow down or potentially outright stall in its functioning, with severe consequences that potentially lead to calamity or death. To various degrees, other types of facilities such as grocery stores or office buildings experience less disruption of operation than a hospital if certain lifelines are broken or compromised. That is, there are more alternatives and flexibility for basic continuous operation for less complex societal functions, but their resilience requirements are not to be trivialized. The stakes are highest with hospitals, however, in which robust design for resiliency with appropriate backup systems and supplies is absolutely crucial.

Hospital function faces other challenges typically not faced by other types of societal functions that intensify the quest for resilience and sustainability. Concurrent disasters challenge all facilities regardless of type, but hospitals face greater challenges and dilemmas. If a wildfire or earthquake occurs during a pandemic, or recurring pandemic, the proximity of one type of patient to others infected with highly infectious disease can amplify the rate of transmission. Solutions entail greater personal protection for patients and hospital staff alike, more temporary beds, increased number of shelters for isolation, alternative and transfer staff to relieve skilled shortage, and trade-offs with acute versus non-acute beds in ICUs. ERs are especially vulnerable to concurrent hazards.

Necessity of a Community-Based Framework for Resilience

As recognized by FEMA, systems of lifelines should be viewed in the context of a whole community, not just in terms of a single societal entity. In a community, various functions and services are all dependent on shared infrastructure to various extents, such as roadways, water, communication networks, power sources, and skilled human capital. A hospital’s internal systems may all be whole, but if a storm damages a roadway or knocks out a powerline, or both, it cannot receive patients and its systems dependent on power become inoperable. Backup power is typically well attended to in hospitals through internal redundancy, though not always in other types of facilities. But power, roadways, and transit services are a community affair that affect many societal functions and services such as food supply, travel to work, and social services.

It is interesting that the Covid pandemic has demonstrated that many functions in society can operate well remotely, such as certain jobs in a company, but that possibility is severely limited with a majority of hospital operations. Advances in technology, though, are changing operational frameworks such that medical interventions and certain surgeries done remotely are becoming more and more feasible. In some cases, critical needs such as life-saving drugs can be transported by drones in a disaster, if winds or rain are not present or too strong. But transporting patients and staff is largely another matter. In the final analysis, transportation needs require embracing a community-based approach to resilient design.

There is an existing standard for community resilience, ASTM-E3130, Standard Guide for Developing Cost-Effective Community Resilience Strategies, and a proposed methodology inspired by FEMA’s lifeline system. The proposed methodology, by Zachary Kennett and Milagros Nanita-Kennett, is titled Community Resilience Lifeline Systems (CRLS) Methodology. The ASTM standard provides an economic decision methodology for achieving community resilience. The CRLS addresses all of the 7 lifelines overseen by FEMA and is properly comprehensive in its structure and mode of application. Currently, the CRLS has the acknowledged limitation that it does not address the interaction and interdependency of the various lifelines. In time, this deficiency needs to be addressed. The Center for Risk-Based Community Resilience Planning (CRBCRP), a 12-university consortium funded by the National Institute of Standards and Technology (NIST), integrates the three elements of physical infrastructure, social functioning, and economic vitality of a community. CRBCRP is developing computationally-based decision tools and seeks to make collaborative links with various disciplines at large that can bridge the gap between its academic pursuits and practical application. When disaster strikes, the need for practical community-based initiatives to assure continuity of function and speed of recovery compels an integration of the three listed elements on the scale of the whole community.  

In emphasis, a facility may be well designed and resilient in its various components and basic structure, but if critical external lifelines are not intact and functioning, the purpose of the facility cannot be served and thus the facility is not resilient as a functioning whole. The bottom line is that, across the board in societal functions, resilience only makes sense in a community-based context.

Hierarchies of Importance and Trade-Offs

Hierarchies of importance and trade-offs are an inescapable reality in all facets of daily life, and hospitals are no exception. However, making trade-offs in operation and cost is less forgivable for hospitals compared to many other enterprises in society. Systems of triage, which are a form of trade-off in hospital operations, will always be required in the face of complex challenges with finite resources. An example would be the decision to discharge a partially healed patient in intensive care to make room for a far more critical patient. In the case of a grocery store, if certain food items cannot be delivered for whatever reason, other stocked food items typically can be substituted. With hospitals, it is usual that a specific drug is unique and there can be no substitution. There are creative solutions ever emerging for challenging dilemmas for all facility types, and a clear goal is to achieve resilient designs that minimize any negative consequences associated with confounding problems that require unsettling trade-off decisions.

Conclusion

In general, lifeline systems that serve society’s vital enterprises can become quite complex and multi-faceted. To effectively design, manage, and maintain networks of lifelines, it is important to understand them and their composite of links and essential resources. Most critically, it is important to look at the essential functions and purpose as a whole for any given entity or facility—a supermarket, residential or office building, hospital, airport, power plant—to determine what lifelines are required to sustain operation and safety, and how to design, manage, and maintain them resiliently. In the process, it is necessary to examine and debate in any given instance of lifeline systems which individual lifelines play the most dominant roles and what backup systems and other redundancies are imperative to assure continuing function in the face of disruptive forces. Critically, most, if not all, facilities that provide essential societal services, depend on resilient lifelines external to the physical structures that house them. This reality puts a vital perspective in how we view the stewardship of our various enterprises. Innovations of various forms play a crucial role in our stewardship.  

In designing and assessing our societal functions, we need to investigate and elucidate the myriad factors at play, which can be a formidable task. We should ever strive toward simplicity in our designs and operations. Toward that goal, we clearly need to develop better tools to guide our human minds through the vast complexities we increasingly face in our societal functions. Thankfully, our human ingenuity is producing novel tools, including AI, that promise to help harness and tame the complexities we encounter. Importantly, in the final analysis our efforts make most sense from a community-based perspective. 

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