Evolving to meet the new UL 7th Edition standard, Apollo reveals how innovative designs in smoke detection balance reliability with next-level, intelligent performance.

Underwriters Laboratories (UL) have recently introduced new requirements for smoke detectors and interface modules. Apollo has responded by building the most solid, stable, and dependable fire detector yet based on their decades of experience and innovation in fire detection.

From January 14^th – 16^th, Apollo will be exhibiting at Intersec 2025, inside the UK pavilion at the Dubai World Trade Centre. Hall 4 – stand G33. The company will be showcasing its upcoming sounder bases along with the UL offering. Find out more about the offering below.

The challenge

One of the biggest challenges customers face is false alarms. UL knows this too, and through research conducted by the National Institute of Standards and Technology (NIST), they have introduced new requirements for smoke detector manufacturers, like Apollo, to reduce the risk of false alarms. At the same time, UL has responded to the evolution of construction methods and materials that can change how fire behaves in a building. This has led to the introduction of a new fire test requiring faster and earlier detection of flaming fires than ever before.

Apollo’s solution

Apollo focuses on getting the basics right. This starts with the performance characteristics of the smoke sensors. Key benefits include:

• Integrated isolators: Soteria UL Detectors and Modules have integrated isolators to reduce installation costs. Integrated isolators ensure the highest possible safety against loop failures such as short circuits, allowing for the creation of Class X systems.
• UL864 10^th Edition compliance: Fully compliant with UL864 10th Edition, including all earth fault detection functionality (Modules only – Smoke detectors are fully compliant to UL268 7^th Edition) 
• Robust design: Developed with improved immunity against external electromagnetic interference and adverse environmental conditions.
• LED indicators: Equipped with tri-coloured LEDs for clear status indications: red for alarm, green for polling, yellow for isolation, and flashing yellow for fault.
• Ease of installation: Quick and easy installation with SEMs terminals that accept US fire cabling as standard. Compatible with standard US back boxes.

Mitigating against false alarms

An optical smoke sensor must be protected from stray light, dust, and insects. These roles are all fulfilled by the enclosure, which is referred to as the optical chamber. While blocking these potential nuisances, the chamber must freely admit smoke, allowing it to be measured by the optical sensor.

This has led to the unique chamber design of Soteria UL, which collects smoke from the outer edges of the detector, removing impediments to airflow and achieving particularly fast fire detection.

Addressing smouldering fires

Smouldering fires often generate vast amounts of smoke without sufficient heat to propel it into the detector. This problem worsens with the stack effect, where pressure differentials between the ceiling cavity and a room prevent smoke from entering the detector. Soteria UL overcomes this with a patented vent design, which:

• Allows pressure differentials to be exhausted through a carefully positioned lid hole, ensuring unimpeded smoke flow.
• Enables condensation from ceiling cavities or cable conduits to escape without harm.

Superior directionality and optics

Uniform performance is critical, no matter the smoke’s direction. UL tests detectors in four orientations, allowing a variation of ±/-50%. Apollo exceeds this by testing detectors at 360 orientations and achieving a variation of less than 10%/ft. This ensures balanced sensitivity, avoiding the need for overly sensitive settings that could trigger false alarms.

Once smoke enters the chamber, the optical sensor measures it while discounting false readings. Apollo’s optical sensor uses an industrially rated InfraRed (IR) light source and a custom Application Specific Integrated Circuit (ASIC) to detect scattered light caused by smoke.

“By leveraging Mie theory, which explains how smoke particles scatter light, the patented optical sensor design distinguishes between smoke from fires and aerosols produced by cooking or other nuisances.”

Apollo

Advanced dust and insect defence

Traditional detectors often suffer from IR light reflecting off chamber walls due to dust or insects. Soteria UL uses a serpentine air inlet to block dust and a fine nylon mesh to prevent larger insects. For smaller particles, the chamber design:

• Utilises a patented light-absorbing surface to prevent IR light reflection.
• Eliminates surfaces where insects or dust could interfere with the sensor.

This ensures that even under challenging conditions, Soteria UL maintains reliable performance without false alarms.

Precision manufacturing

Every Soteria UL detector is produced and certified to conform to a narrow range of sensitivity. This guarantees consistent behaviour across all units, avoiding variability in sensitivity to nuisances or fire attributes. A blend of skilled hand assembly and automated processes ensures exceptional quality. Each product is individually measured and calibrated for smoke sensitivity.

Rigorous quality control protocols are implemented at every stage of production, utilising advanced testing equipment to verify performance standards. The precision manufacturing process also incorporates state-of-the-art materials and components, enhancing durability and reliability. This attention to detail ensures that Soteria UL detectors perform optimally in diverse environments, providing dependable protection against fire hazards.

Intelligent signal processing

With a strong foundation in sensor performance, Apollo’s intelligent signal processing balances the need for fast fire detection with false alarm prevention. By avoiding overly complex algorithms, it achieves reliable performance with optimal smoothing, delay, and enhanced detection for fast-flaming fires.

The detector processes information continuously and signals the panel with exceptional speed when it identifies a fire. The system integrates adaptive learning capabilities, allowing it to adjust to varying environmental conditions and improve accuracy over time. Advanced filtering techniques are employed to distinguish between genuine threats and benign disturbances, ensuring that responses are both swift and precise.

Keeping you safe

Keeping people safe from fire, every second of every day. From January 14-16, Apollo will be exhibiting at Intersec 2025, inside the UK pavilion at the Dubai World Trade Centre. Hall 4 – stand G33. The company will be showcasing its upcoming sounder bases along with the UL offering.

This article was originally published in the January 2025 issue of International Fire & Safety Journal to read your FREE digital copy, click here.