International Fire Buyer: Revolutionizing Fiber Optic Linear Heat Detection

AP Sensing's new N45-Series fiber optic Linear Heat Detection (LHD) system is featured in the June edition of International Fire Buyer! In the article, we explain what fiber optic LHD is, its benefits and advantages, and assets that benefit from our monitoring solution, including:

  • Solar farms (greenfield & rooftop)
  • Battery storage
  • Tunnels (road, rail & utility)
  • Conveyor belts
  • Food processing facilties

Read article on page 18/19 here.

AP Sensing, a leading German manufacturer of fiber optic sensing solutions, recently launched its third generation Linear Heat Detection (LHD) system – the N45-Series. With unparalleled performance, reliability, safety, and user-friendliness, the N45-Series sets a new standard for fiber optic LHD.

What Is Fiber Optic Linear Heat Detection?

Fiber optic LHD is revolutionizing fire detection and monitoring. By utilizing a fiber optic sensor cable with a diameter of only 4 mm, the N45-Series provides temperature measurements at every point along the entire cable, quick detecting changes in temperature. It detects hotspots and fires, providing precise information on fire location, size, temperature and spread. Fiber optic LHD is used in a wide range of applications including traffic and utility tunnels, car parks, conveyor belts, production areas, metro stations, food processing, data centers, cable trays, solar farms, refineries, chemical plants, warehouse facilities, coal storage, and battery storage.

Benefits & Advantages: Fiber Optic LHD

Fiber optic LHD offers many advantages compared to traditional fire detection methods (and other, non-fiber optic LHD systems including analog, digital and multipoint LHD), including:

Extended coverage capabilities and continuous monitoring

A single fiber optic LHD cable can cover long distances, eliminating the need for multiple sensors or detectors, and providing a cost-effective solution that efficiently monitors large areas. Additionally, Fiber optic LHD systems are not limited by cable length restrictions, as performance remains consistent regardless of the cable length, ensuring reliable monitoring across extended areas.

High sensitivity and temperature resolution

Fiber optic LHD provides a more accurate and responsive monitoring solution than other systems which may have limitations in detecting subtle temperature variations, potentially leading to delayed or inadequate fire detection.

Precise event localization

AP Sensing’s LHD system locates and pinpoints the exact location of temperature changes, hotspots, or fire events. It provides accurate and quick information on the location, size, and spread of a fire, with pre-alarms and early intervention measures aiding in rapid responses and fire prevention.

Versatility & effectiveness in harsh environments

AP Sensing LHD systems are versatile and offer maximum reliability, even under severe conditions. Fiber optic LHD systems are immune to electromagnetic interference, certified for explosive environments caused by gas or dust, and are suitable for a wide range of harsh environments including dirt, dust, corrosion, humidity, extreme temperature changes, radioactivity and solvent vapors. Additionally, LHD systems are adaptable to varying installation requirements and seamlessly integrate with existing alarm systems to immediately trigger alarms, activate trigger sprinkler systems, or send notifications to relevant personnel.

Low maintenance requirements

AP Sensing’s fiber optic LHD systems require minimal maintenance. Fiber optic cables are durable, with an average 30-year life span, ensuring reliable performance over time.

AP Sensing’s N45-Series LHD

AP Sensing’s LHD N45-Series boasts the longest certified distance range on the market, with up to 16 km and four channels for all distance ranges. An intuitive, fully integrated web server offers simple configuration via browser, one-click validation of compliance configuration settings, 2000 configurable alarm zones per channel, and up to 98 integrated relay contacts.

Safety and system reliability are a key feature of the N45-Series LHD, with an extensively tested, ruggedized housing design (including a wide selection of IP66 housing solutions and 19” wall mount), state-of-the-art IT security standards, and benchmark levels of quality. The system offers the most complete set of type tests and certifications on the market including EN54-22 (VdS), UL 521 (UL), CAN/ULC-S530, SIL-2, and ATEX and IECEx for critical areas.


For more information on AP Sensing’s fiber optic LHD technology, visit or contact us at