Fire

Tunnels are among the most challenging environments for fire safety. Enclosed spaces, heavy traffic, complex airflow patterns, and critical evacuation procedures mean that even a small fire can escalate into a major incident within minutes. Traditional detection systems, while useful, often work in isolation: smoke detectors trigger alarms, flame cameras identify visible fire, and suppression systems deploy water or foam. The problem is that these standalone systems don’t always locate the source of the fire accurately or communicate effectively, and in environments where every second counts, that can make the difference between containment and catastrophe.

That’s why the industry is increasingly moving towards hybrid fire detection systems, integrated solutions that combine multiple technologies into a single, intelligent network. By merging the strengths of fiber optic linear heat detection (LHD), flame detection cameras, and AI-powered analytics, operators gain earlier warning, greater accuracy, and clearer situational awareness. The result is a faster, more coordinated response that saves both lives and infrastructure.

Why traditional systems are struggling

Point detectors and smoke sensors were designed for environments where air is relatively still and threats can be monitored from fixed positions. A tunnel is the exact opposite. Fans move air constantly, pushing smoke away from detectors. Curved designs break up lines of sight. Noise, dust, and temperature variations all create conditions where alarms can be either delayed or misleading.

This creates two critical problems. First, operators may not receive a warning until a fire has already spread beyond its point of origin, losing valuable seconds for evacuation and suppression. Second, when alarms are triggered too easily, operators lose confidence in the system. False activations can lead to tunnel closures, unnecessary water deployment, and a loss of public trust in safety procedures. A detection system that is too slow or too sensitive creates operational risk, which is why many operators are seeking alternatives that give them more reliable, real-time information.

Moving toward a hybrid solution

Hybrid fire detection systems address these challenges by combining different technologies, each one filling the gaps left by another. Fiber optic LHD provides continuous temperature monitoring along the full length of the tunnel. Instead of relying on sensors placed at intervals, a single fiber cable can detect abnormal rises in heat at any point, ensuring there are no blind spots.

Flame detection cameras add another layer, giving operators rapid visual confirmation of any incident. By integrating thermal imaging and analytics, these cameras can distinguish between genuine flames and harmless heat sources.

This creates a more intelligent platform that doesn’t just tell operators when a fire has already broken out but can identify precursors, such as electrical overheating, that signal risk in advance. In practice, this means fires are detected sooner, alarms are more accurate, and response strategies can be tailored to the exact location and severity of the incident.

Case in point, the Santa Lucia Tunnel

The Santa Lucia Tunnel presented a demanding brief. At 7.8 km long, one of the largest single-arch, three-lane tunnels in Europe, it required a fire detection solution that could provide complete, dependable coverage across its entire length while coping with heavy traffic, exhaust particulates and complex airflow. The owner, Autostrade per l’Italia, specified a high-performance system that would detect fires rapidly, tolerate tunnel contaminants, and integrate seamlessly with the tunnel’s automated fire-suppression logic.

To meet that brief, the project team chose a fiber-optic linear heat detection approach. The installation used Bandweaver’s FireLaser DTS paired with the FireFiber AT armoured sensing cable, installed at roof level (around 7.2 m) and fixed at regular intervals to give a continuous thermal profile with one-metre spatial resolution. Because the tunnel’s sprinkler system was already divided into many discrete zones, the detection design was mapped into 982 zones, so temperature readings and alarm logic aligned exactly with the suppression layout.

Redundancy and precision were central to the design. The scheme employed two detection cables along the tunnel roof and a multi-controller configuration that provided resilience against cable damage or controller faults. The FireLaser units are capable of EN54-22 compliant measurements every five seconds, a significant advantage over alternatives that take much longer per channel, and the FireLaser provided the accurate location data required to trigger only the specific sprinkler valve associated with the detected hotspot. The overall detection architecture was intentionally hybrid: fiber LHD provided the precise thermal location, while video flame detectors and optical beam smoke sensors formed part of the automated logic that controls suppression activation.

Commissioning and calibration were handled on site by RAET with oversight from the project engineers. The system took three weeks to commission; during installation the team encountered expected practicalities such as cable sag, which required zone recalibration. Because the FireLaser’s zones are software-configurable, RAET was able to re-reference the sensing cable to match the sprinkler zones using cold-spray reference points, and the final configuration was signed off by independent consultants. The project demonstrates how a distributed fiber solution can be engineered to meet exacting operational and integration requirements in the most challenging tunnel environments.

The outcome delivered what the operator asked for: faster, location-precise detection that is robust against dust, exhaust and moisture; continuous one-metre sampling along the tunnel; redundant architecture; and tight integration into the tunnel’s control and suppression systems. These attributes combine to reduce false activations, support targeted suppression, and provide operators with the confidence and clarity needed to act quickly when every second counts.

The future of tunnel fire safety

The Santa Lucia Tunnel is just one example of how hybrid detection is already proving its worth. As tunnels grow longer and traffic volumes increase, reliance on any single technology will no longer be sufficient. Future projects will continue to push for smarter, integrated systems that not only detect fires faster but also give operators the context they need to make the right decisions instantly.

At Bandweaver, we are helping operators move beyond traditional fire safety approaches with innovative hybrid solutions that combine fiber optic sensing, video analytics, and AI. These technologies are already transforming tunnel safety, and we’re ready to help you implement them.

If you’d like to learn more about how our solutions can support your next tunnel project, get in touch with our team today.

Traditional fire detection systems weren’t built for the realities of tunnels, substations, chemical plants, or heavy industrial environments. In these settings, smoke and heat behave unpredictably, and when detection fails, the consequences are catastrophic. What follows is a dangerous cycle: missed alarms, loss of confidence in the system, and slower emergency responses.

It’s time to stop asking, “Does it work in the lab?” and start asking, “Does it work where it matters?” Fiber optic linear heat detection is redefining what’s possible in fire safety, proving it’s not only suitable for harsh environments but optimised for them. In this article, we’ll explore the critical role this technology plays in protecting the world’s toughest and most high-risk environments.

Why “ordinary” fire detection doesn’t cut it

Conventional smoke and thermal sensors are designed with stable, clean environments in mind, environments with clear air, minimal interference, and consistent conditions. But for many high-risk facilities, this couldn’t be further from reality.

In substations and transformer enclosures, electromagnetic interference can scramble readings or trigger false alarms. In more complex settings like chemical plants, tunnels, and enclosed industrial spaces, factors like dust, humidity, or airborne particulates can obscure or degrade standard sensors altogether.

This creates a serious risk for organisations operating in extreme environments with high-value assets and infrastructure. When sensors fail, or when false alarms erode confidence, operators hesitate. Responses are slow. Fires escalate.

Fiber optic heat detection: a built-in advantage

In volatile, unpredictable conditions, fiber optic linear heat detection offers a distinct advantage.

Using a passive sensing cable, with no in-field electronics, power supplies, or communication modules, it eliminates the typical points of failure found in traditional systems. The cable is immune to electromagnetic disturbance, corrosion, temperature extremes, and airborne contaminants.

What’s more, every metre of fiber optic cable acts as a continuous, highly accurate heat sensor, delivering precise thermal mapping across large distances. These systems integrate easily with CCTV, suppression equipment, and intelligent software, creating a comprehensive fire detection and prevention solution that enables not only timely reaction but also smarter, data-driven response strategies.

Where fiber optics shine in tough environments

Tunnels, subways and rail networks
Fiber optic cables can be run along entire tunnels or infrastructure layouts, detecting subtle temperature changes or fast-rising heat from cable faults or fires. This allows suppression or ventilation systems to activate at the precise point of risk, before the situation escalates.

Heavy industry and mining operations
These are among the most demanding environments, where early detection is critical. Fiber optic systems can identify overheating bearings, blocked chutes, or overloaded motors, often before any smoke or flames appear. This enables rapid intervention and helps avoid serious damage.

Oil and gas facilities
With zero electronics in hazardous zones, fiber optic detection is perfectly suited to environments containing flammable gases or volatile compounds. It allows continuous monitoring without increasing risk, something traditional systems can’t offer.

Energy infrastructure
In high-voltage substations and transmission areas, where conventional systems degrade quickly, fiber optics remain stable and reliable. They provide early warnings of cable overheating or transformer faults that could otherwise lead to catastrophic fires.

High-moisture or washdown areas
Environments like food processing facilities, where constant cleaning and high humidity are standard, can quickly corrode or compromise standard detectors. Fiber optic systems, by contrast, remain unaffected, providing consistent and long-term fire safety coverage.

Performance you can measure

When a fire or abnormal heat source emerges, fiber optic sensing cables can detect the event to within 1°C and 1 metre, often before flames are even visible. In one real-world example, a customer using our linear heat detection system on a conveyor belt was alerted to a heat spike near a bearing. The maintenance team responded swiftly, replaced the affected part, and prevented what could have been a serious fire.

Preventing just one incident like this can justify the cost of the system, saving thousands in asset damage, downtime, and emergency response. Over time, the benefits multiply. Unlike traditional systems, which are often subject to breakdown and expensive maintenance due to environmental wear, fiber optic systems operate for years with minimal intervention.

Crucially, fiber optics drastically reduce false alarms. In harsh environments, false alarms are more than a nuisance, they erode trust and dull the urgency of real emergency response. With fiber optic fire detection, you get greater specificity and accuracy, ensuring teams are only deployed when it truly matters.

Overcoming the awareness gap

Despite these clear advantages, many fire safety professionals still associate fiber optic systems with older, copper-based technologies, which are outdated, fragile, and expensive. That couldn’t be further from the truth.

Modern fiber optic systems are lighter, faster, smarter, and more cost-effective per metre than ever before. Yet awareness hasn’t caught up. In many regions, standards and regulations still lag behind the capabilities of this technology, creating a bottleneck to broader adoption.

That said, change is happening. In the Netherlands, for example, rigorous new testing and commissioning standards have been introduced, standards that fiber optic systems meet effortlessly. This growing recognition is setting the tone for wider industry adoption and elevating expectations around fire detection performance.

Laying the blueprint for resilient fire safety

It begins with rethinking fire detection, starting with a clear-eyed audit of your environment. What are the conditions really like? Are your current systems fit for purpose, or just convenient?

Forward-thinking partners are already reshaping their fire safety strategies. They’re implementing fiber optic detection across new sectors and integrating with other smart technologies to create a layered, responsive defence strategy.

Fiber optic linear heat detection isn’t just adequate; it’s engineered for the job. It’s time to stop settling for outdated systems and start investing in solutions designed for the environments you operate in.

Join the global movement transforming fire safety, one cable at a time: https://www.bandweaver.com/about-bandweaver/partners/

Imagine, you’re driving through a long tunnel when traffic starts to slow and suddenly, smoke fills the air. Visibility drops as headlights faintly glow through the haze; you instinctively check for an escape route but can’t see where to go. No warnings, no alarms. The tunnel becomes a trap, heat intensifying as toxic gases replace oxygen. Will emergency responders reach you in time?

Tunnel fires can reach 1,000°C in under 5 minutes – extreme temperatures such as these are hot enough to melt vehicles and infrastructure. One of the most dangerous environments for a fire to occur is in a tunnel, with limited exits, unpredictable smoke movement, and rapid heat build-up. This leads us to question: are fire detection systems reacting fast enough?

The science of fire spread in tunnels

Heat, smoke, and toxic fumes behave differently in a tunnel than in open-air environments. Often, tunnels are fitted with ventilation systems to reduce pollution; however, these systems can accidentally push smoke towards those evacuating. This means a superheated cloud of smoke and toxic gases travels faster than people can escape. Fire growth accelerates in this environment due to the confined space and poor ventilation, creating a wind tunnel effect that allows even small fires to grow rapidly. Temperatures also rise faster, increasing the risk of rapid flashover.

Traditional fire detection systems can take 2-5 minutes to trigger an alarm; this is often too late and allows fires to reach a critical size before suppression efforts begin. When comparing this to a timeline of fire escalation in a tunnel, the results are concerning:

– 1 Minute: A vehicle catches fire, building up heat without triggering an alarm.

– 3 Minutes: Thick clouds of smoke spread, making evacuation difficult.

– 5 Minutes: Flames engulf the tunnel; visibility drops to zero, and the fatalities are certain.

What if fire detection had happened at 30 seconds?

Emergency services would be alerted before the fire becomes uncontrollable for a more effective response, while tunnel operators can instantly trigger fire suppression or evacuation procedures. Overall, lives would be saved and damage to infrastructure minimised.

Why traditional fire detection fails in tunnels

Smoke Detectors:

• Inconsistent, smoke moves unpredictably in tunnels due to ventilation and airflow complexities.
• Exhaust fumes and humidity can cause false alarms or tamper with detection abilities.

Flame Detectors:

• Due to requiring visible flames, fire detection occurs once a fire has escalated dangerously.
• Blind spots within the tunnel can mean fires are missed.

Cameras:

• Smoke can obscure vision before a camera can detect anything.
• Thermal cameras only detect large heat sources, not early-stage temperature spikes.

False alarms are a significant downside of traditional detection systems; misinterpretation of dust, exhaust fumes, and environmental conditions leads to unnecessary closures and disruptions. Frequent false alarms can lead to alarm fatigue, which over time reduces the speed and efficiency of response times.

What happens when fire detection is too slow?

Failing to detect fires soon enough can have devastating effects. The Mont Blanc Tunnel Fire in 1999 is a harrowing example of this. One morning, a truck carrying flour and margarine caught fire inside the tunnel; this caused a rapid spread of both smoke and heat throughout. Due to fire detection systems failing to react in time, the fire was able to spread to devastating extremes while drivers were unaware of any dangers. As a result, people became trapped in their vehicles as flames engulfed the tunnel, causing 39 lives to be lost.

Comparatively, the Gleinalm Tunnel fire in 2018 was swiftly dealt with due to an innovative fire detection system. Within seconds the fire was detected, and tunnel fire suppression measures kicked in, allowing those in the tunnel to safely evacuate. This clearly shows the phenomenal impact of advanced fire detection systems in mitigating the risks associated with tunnel fires.

How FireLaser detects tunnel fires before they become disasters

Unlike traditional detectors, our cutting-edge fiber optic linear heat detection system FireLaser detects heat at its earliest stage, before flames or smoke even appear. This allows potential fires to be suppressed before they have a chance to spread. Due to the fiber optic sensing cable, organisations can rule out false alarms as the system is unaffected by airflow, vehicle emissions, fog, or dust.

To enhance fire response, FireLaser has real-time pinpoint accuracy to alert operators within seconds to the exact location of a temperature spike. Even in tunnels hundreds of meters long, the heat source can be located precisely, with no blind spots or gaps to ensure continuous monitoring. The versatility of our FireLaser system doesn’t just apply to its robustness and preciseness. FireLaser is scalable and adaptable to various tunnel types, such as road tunnels to prevent vehicle fires causing mass casualties, rail tunnels to ensure safe evacuation and train operator response, and utility tunnels to protect infrastructure from overheating cables or pipe failures.

Why tunnel operators & fire specialists choose Bandweaver’s FireLaser

Countless organisations globally trust in our fiber optic linear heat detection systems to guarantee safety in road, rail, and utility tunnels. FireLaser is proven to maintain its exceptional performance even in extreme tunnel conditions. Through successful implementation worldwide in high-risk tunnels, we know the system can withstand temperature extremes, humidity, and environmental contaminants.

We believe in making fire detection systems not only more effective in their performance but also in their usability as a tailored fire safety solution. FireLaser is highly adaptable, allowing easy integration into existing tunnel safety systems. Imagine how much quicker fire responses could be when FireLaser works alongside fire suppression, ventilation, and traffic management systems. This is also an incredibly cost-effective implementation, especially for larger tunnels, as there is no need for expensive infrastructure overhauls.

If you’ve worked with traditional fire detection systems, you’ll know the extensive maintenance required to keep them up and running. Through our FireLaser system, this is a thing of the past. With no moving parts or electronic sensors that fail over time, the system requires little to no maintenance over its long lifespan.

Every second counts

The difference between life and death in a tunnel fire is early detection. We’ve seen throughout the past decades traditional systems failing to react early enough, resulting in fatalities. It’s time for change; with the FireLaser system, tunnel operators have the best chance to detect and respond to fires quickly.

Our partners can offer their clients advanced fire safety solutions that allow for fast responses that save lives. Want to provide the best fire detection solutions for tunnels?

Get in touch to discuss our FireLaser system here.