SMS SenTRI Addressable Optical Heat Detector with Sounder & High Power VAD

FAQs

What is the difference between high power and low power VAD variants?

High power VAD variants (SEN-770-VAD-HPR and SEN-770-VAD-HPW) deliver maximum visual alert capability for environments requiring enhanced visibility, such as high ambient light areas or large open spaces. Low power variants (SEN-770-VAD-LPR) provide efficient operation for standard applications whilst consuming less loop power, potentially allowing more devices per loop. The choice depends on your specific visibility requirements and system design constraints.

Should I choose red or white VAD flash colour?

White VAD variants (SEN-770-VAD-HPW) typically provide superior visibility and contrast in most environments, particularly where varied background colours or high ambient lighting exists. Red VAD variants (SEN-770-VAD-HPR and SEN-770-VAD-LPR) follow traditional fire alarm colour conventions and are immediately recognisable as fire safety equipment. White is generally recommended for maximum effectiveness, whilst red maintains consistency with established fire safety aesthetics.

How many SEN-770-VAD devices can be installed on a single loop?

Loop capacity depends on the specific control panel model and loop card specifications. SenTRI TWO and FOUR systems with EN54-compliant loop cards can typically accommodate up to 100 sensor-sounder-VAD devices and up to 200 total devices per loop. The exact number depends on device mix, cable length and power distribution. A loop load design calculator should be used to confirm actual loop design limits for your specific installation.

Do these sensors require separate bases?

Yes, the SEN-770-VAD sensors require the SEN-700 detector base, which is supplied separately. One base fits all sensors in the SenTRI range, reducing installation complexity and stock requirements. The universal base design simplifies first fix installations and allows for flexible sensor selection during commissioning.

What sensitivity states are available on these multisensors?

The SEN-770-VAD optical heat multisensors offer multiple sensitivity states including medium sensitivity optical with Class A1 heat (State 0), low sensitivity optical with Class A1 heat (State 2), and various other combinations. Different states can be programmed for different time periods, allowing day/night sensitivity adjustment to minimise unwanted alarms whilst maintaining reliable fire detection performance.

Can the sounder and VAD be controlled independently?

Yes, the integral sounder and VAD can be controlled independently through the control panel programming. This enables silent VAD-only alerts for staff in public areas ahead of general evacuation, supporting managed evacuation strategies in occupied premises such as retail spaces, entertainment venues and healthcare facilities.

Are these sensors compatible with older SMS fire alarm systems?

The SenTRI system products are designed with backwards compatibility in mind and can be used on predecessor systems within the SMS portfolio. However, compatibility should be verified with SMS technical support for your specific panel model to ensure full functionality and compliance with current standards.

What is the built-in loop isolator feature?

Every SenTRI device includes an integral loop isolation unit as standard. This allows any device to be positioned at zone boundaries and enables quick identification of system or wiring faults by automatically isolating faulty sections of the loop, maintaining system operation in unaffected areas and simplifying troubleshooting during maintenance.

How are the programmable tones configured?

Sounder tones are programmed through the control panel software, allowing customisation to avoid confusion with other building alarm systems. The sensors support up to three different alarm tones for phased evacuation protocols, with synchronisation across loops ensuring clear and unambiguous emergency messaging throughout the protected premises.

What standards compliance do these sensors achieve?

The SEN-770-VAD sensors are LPCB certified and comply with EN54 Part 7 for smoke and heat detectors, EN54 Part 3 for sounders, and EN54 Part 23 for Visual Alarm Devices. Systems using these devices meet the requirements of BS5839-1:2013 and Building Regulations Approved Document B&M, ensuring full compliance with UK fire safety legislation including the Equality Act 2010 accessibility requirements.