Fire Friday #7: Quality & Reliability

How is AP Sensing’s LHD system designed and tested to ensure robustness and utmost reliability?

Quality and reliability are top priorities in fire protection. Since fire protection ultimately involves saving lives and preserving valuable assets, the requirements cannot be high enough. We at AP Sensing have therefore designed our LHD products for performance, paying special attention to reliability and quality during the development phase. Our products are also extensively tested for robustness. AP Sensing’s LHD products are superior in various aspects:


Smart Product Design

Our patented Code Correlation Concept enables the use of particularly low laser power, which not only increases the safety of the product but also reduces the aging and degradation of the laser.  Our unique single receiver design eliminates drifts and stabilizes the measurement signal completely. This increases long-term stability and thus false alarm resilience, making any calibration during lifetime of the system unnecessary. All our products work with a real-time operating system (RTOS), which has been specially developed for safety-relevant applications. This operating system is also used in the aviation industry (e.g. F-18 Hornet) or in space travel (Rover Pathfinder Mars mission), i.e., operations where a failure would have significant consequences.

An active cooling system enables a wide temperature range without the sensitive electronics being exposed to outside air, as the outside air may contain dust, dirt, or corrosive particles. All our LHD products operate from -10 °C to +60 °C and no filters or alike need to be replaced during the system lifetime. Many of these development ideas are the result of our extensive experience, based on the principles of the world leaders in measurement technology, Hewlett Packard (HP) and Agilent Technologies. As heir to HP and Agilent Technologies' fiber optic sensor division, AP Sensing continues to deliver products that exceed the standard for fiber optic LHD.



Robustness is equally as important as a clever design. Our LHD products go through tough type tests that include shock (up to 30 g), vibration resistance (500 Hz) and EMC (to demanding railroad standards). For example, in one test the evaluation unit is dropped from all sides at a height of about one meter onto a hard surface. The test is considered passed if the evaluation unit measures according to specification after the test. We offer our LHD systems in various form factors, such as the standard rack system, but also with a wall mount housing. According to IP66 classification, our wall mounted system can also be installed in outdoor environments.  

The enormous effort invested into the development and testing of our products is worth it. In an external SIL assessment the Probability of Dangerous Failure per hour (PFH) of our fiber optic LHD system was calculated at 0.000000105 and the current annualized five-year failure rate is 0.7%. Quality made in Germany.

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AP Sensing Fire Friday