When maintaining an Edwards EST addressable fire alarm system, one of the most common questions technicians and facility managers face is: what’s the difference between the SIGA-PD and the SIGA-PS? Both are top-selling intelligent photoelectric smoke detectors from Edwards, but they serve different purposes. This guide breaks down the specs, applications, and compatibility of each so you can confidently order the right replacement.
Overview: The Edwards EST SIGA Series
The SIGA series is Edwards EST’s line of intelligent, addressable life safety devices. These detectors communicate directly with compatible panels over a Signature loop, providing precise location data and real-time diagnostics. They’re a staple in commercial buildings, hospitals, schools, and government facilities across the United States.
The two most common photoelectric models are the SIGA-PD and the SIGA-PS. While they look nearly identical from the outside, they have important functional differences.
Edwards EST SIGA-PD: Intelligent Photoelectric Smoke Detector
The SIGA-PD is a standard intelligent photoelectric smoke detector designed for open-area detection. It uses a forward-scatter light chamber to detect the presence of visible combustion particles — making it ideal for slow, smoldering fires.
Key Specs:
- Detection method: Photoelectric (light scatter)
- Communication: Edwards Signature multiplex protocol
- Operating voltage: 15–32V DC
- Standby current: 45 µA
- Alarm current: 45 µA (same — panel-powered)
- Operating temperature: 32°F to 100°F (0°C to 38°C)
- Compatible bases: SIGA-SB, SIGA-SB4, SIGA-RB, SIGA-LED
The SIGA-PD is used in general occupancy areas — corridors, offices, classrooms, storage rooms, and other spaces where early warning of smoldering fires is the priority. You can browse available Edwards EST SIGA-PD detectors here.
Edwards EST SIGA-PS: Intelligent Photoelectric Smoke Detector with Sounder Base
The SIGA-PS is also a photoelectric smoke detector, but it’s specifically designed to work with sounder bases — most notably the SIGA-AB4GT (audio/visual base). When the SIGA-PS is paired with a compatible sounder base, it can provide local audible notification directly at the detector, independent of a separate notification appliance circuit.
Key Specs:
- Detection method: Photoelectric (light scatter)
- Communication: Edwards Signature multiplex protocol
- Operating voltage: 15–32V DC
- Sounder base compatible: Yes (designed for SIGA-AB4GT)
- Operating temperature: 32°F to 100°F (0°C to 38°C)
- Compatible bases: SIGA-AB4GT sounder base (primary); standard bases also supported
The SIGA-PS is the preferred choice in applications where local tone generation is needed without running separate notification appliance circuits — common in dormitory corridors, patient rooms in healthcare, and retrofit applications. View the Edwards EST SIGA-PS detector product page for current availability.
SIGA-PD vs SIGA-PS: Direct Comparison
Here’s a quick breakdown of the key differences:
- Sounder Base Support: SIGA-PS is designed for sounder bases; SIGA-PD is not
- Use Case: SIGA-PD for standard open-area detection; SIGA-PS where local audio notification is needed
- Base Compatibility: SIGA-PD works with standard SIGA-SB/RB bases; SIGA-PS works with AB4GT sounder base
- Detection Technology: Both use photoelectric light scatter — functionally identical for smoke sensing
- Panel Compatibility: Both work on the same Edwards EST panels (EST3, EST4, QuickStart, iO series)
Panel Compatibility
Both the SIGA-PD and SIGA-PS are compatible with the full range of Edwards EST Signature loop panels, including:
- EST3 and EST3X Fire Alarm Control Panels
- EST4 Fire Alarm Control Panels
- QuickStart QS1 and QS4
- iO64 and iO500
Always verify loop compatibility and device counts with your panel’s programming guide before ordering replacements.
How to Order the Right Replacement
When ordering replacement SIGA detectors, make note of the following before placing your order:
- Check the existing detector model number — printed on the label beneath the detector head
- Confirm the base type — standard sounder base or low-profile base
- Verify panel compatibility — loop card firmware may affect which detectors are supported
- Check for obsolescence — Edwards periodically releases updated versions; a like-for-like replacement is usually possible
For a wide selection of Edwards EST fire alarm replacement parts — including SIGA-PD, SIGA-PS, bases, and more — visit the Edwards EST parts section at Life Safety Consultants. We’ve been supplying commercial fire alarm parts since 2002 and carry both current and hard-to-find obsolete inventory.
