April is National Safe Digging Month, and utility companies across the country are leading efforts to raise awareness about damage prevention. Supported by industry leaders and policymakers, the “call before you dig” message will reach millions – but what happens when that call never comes? To prevent excavation damage without notice, utilities may find an unlikely ally in one of the very assets most at risk.
Fiber optic cable is the most commonly struck buried facility according to the Common Ground Alliance’s (CGA) Damage Information Reporting Tool. While CGA, PHMSA, and others continue to spread the important message of National Safe Digging Month, many infrastructure operators know that “no call” digging will persist. Industry leaders must be prepared for threats that come in all shapes and sizes, and unanticipated excavation is a key concern, but certainly not the only. When non-ticketed or other unintentional digging happens, asset owners who have prepared can turn to fiber as a second line of defense to counter “no calls.”
Fiber optic cable, while being commonly struck itself, also has a hidden ability to serve as a sensor. Known as distributed fiber optic sensing (DFOS), this application over existing broadband-providing fiber optic cable can detect and alert One-Call centers and utility owners about real-time excavation activities or other events surrounding their assets. Notably, when a fiber optic cable shares a right-of-way with other utility lines like water, power, gas, and electricity, that fiber optic cable can be utilized as a real-time continuous monitoring sensor along miles of right-of-way, protecting the entire set of utilities from third-party excavation or unintended access. If there is digging in proximity, the fiber optic cable will hear it and alert before damage occurs.
The secret lies in available hardware and sophisticated software that can analyze and categorize the backscatter or reflectance occurring within a fiber optic cable. Here is how it works for the same conventional optical fibers used for our internet and data transmission:
When laser pulses are sent down the fiber optic line, a very minute amount of backscatter or reflectance occurs in the opposite direction as an inherent property of the fiber material. Acoustic activity, or vibrations, not only on the fiber cable itself but including anything occurring in or near the right-of-way modifies how the backscatter occurs and those changes can be detected. This allows fiber optic cable to hijack what would otherwise be normal material inefficiency and turn it into valuable intelligence and insights.
The interrogator that receives this backscatter information can not only identify within a short linear distance (typically within 30 feet) where the acoustic activity is occurring but also categorize what is occurring. For example, software can often differentiate between an excavator, a person walking, and a manhole being opened or closed. In addition, the software can be calibrated to ignore noise and differentiate between normal events like traffic and unexpected excavation events near a right-of-way. When an activity is detected, categorized, and automatically GIS map located, One-Call centers can receive an immediate notice of excavation activity to check against their system of open tickets.
Among other critical reforms, this gives damage prevention professionals an offense against no-call damage, putting them ahead when they are so often playing defense.
If a One-Call center sees a valid ticket and positive response by locators, they can notify utility operators that work has begun, providing situational awareness that planned activity is now occurring. If no ticket is found, the One-Call center can immediately notify all utility companies near the site of excavation so they can send alerts or teams to the location to intervene and protect the assets.
This example highlights the critical backstop that DFOS can be for the damage prevention industry. Rather than only relying on calls and paint on the ground – which is vital and must remain the standard practice for the foreseeable future – utilizing a fleet of continuously monitoring sensors to give real-time threat analysis and situation awareness along prioritized rights-of-way can prevent more damage and minimize what does occur.
Excavation damage is known to have a 30:1 cost multiplier for total costs. That means that every dollar in direct costs comes with $30 in rippling indirect costs to the community, whether they be road closures and traffic delays, lost productivity from downed service, or healthcare and insurance expenses that arise from an incident. While preventing damage to a pipeline, for instance, is important and can be life-saving, the mitigating value of DFOS can also have enormous economic benefit.
Monitoring vibrations from intended or unintended excavation work is not the only advantage that DFOS can provide. Unlike other sensors and cameras which require power, are limited in visibility, and require maintenance and replacement, the non-powered passive nature of optical fiber cable in conduit is designed to last for decades. Technology companies are advancing detection capabilities with artificial intelligence to provide enhanced categorization over activities of greatest concern. The ability to precisely pinpoint the exact location of a potential issue, unlike many other available sensors or technologies, provides an extremely valuable part of a total solutions damage prevention approach.
Early detection of not only catastrophic potential damage but required maintenance means that teams can directly go to the source of a pipeline leak or facility damage without wasting valuable time walking the right-of-way or triangulating with other metrics. This spared time helps directly reduce the rippling indirect damages that may add up in the meantime.
While no system is perfect or can anticipate every threat, distributed fiber optic sensing can provide improved real-time awareness and at lower cost than almost any other system at scale today. For the damage prevention industry and utility owners and operators, this cannot be ignored. As the pilot program through Texas811 is demonstrating, leveraging fiber optic infrastructure as a backstop to “no call” damage may revolutionize damage prevention, saving lives and money in the process. As more utilities adopt DFOS, will regulators and 811 centers evolve to integrate this real-time intelligence into the standard toolkit for damage prevention?
Benjamin Dierker is the executive director of the Alliance for Innovation and Infrastructure (Aii) the only nationwide public policy think tank dedicated to infrastructure
Paul Dickinson, PhD is the Director of Business Development for Dura-Line. Orbia’s Connectivity Solutions business, Dura-Line, is a leading manufacturer and distributor of high-density polyethylene (HDPE) conduit, accessories, and other connectivity solutions for the telecommunications, transportation, and electrical markets.
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