Apollo ORB-OP-52027-APO Orbis I.S. Optical Smoke Detector

An intrinsically safe optical detector for black and white smoke

The Apollo ORB-OP-52027-APO is the Orbis Intrinsically Safe optical smoke detector. Its sensing chamber measures back-scattered light as well as the usual forward-scattered light, which greatly improves sensitivity to black smoke. Apollo states that its performance is good in black as well as white smoke, unlike traditional optical detectors that perform far better in white smoke.

The detector uses algorithms to decide when to change to the alarm state, which removes the likelihood of an alarm from smoke of smoking materials or another non-fire source and reduces false alarms. A second part number, ORB-OP-52028-APO, is the version with a flashing LED. The mounting base ORB-MB-50018-APO must be ordered separately.

Technical specifications

Status indication and diagnostic features

Orbis detectors have a 360 degree integral indicator and a remote output LED characteristic of 4.7 kilohm connected to the negative supply. StartUp confirms correct wiring polarity with a once-per-second red flash. FasTest is a four-second functional check. DirtAlert flashes yellow when the drift compensation limit is reached, and SensAlert flashes yellow every four seconds when the sensor is not operating correctly.

The flashing LED version flashes red every four seconds in normal operation at the end of FasTest. Apollo recommends Orbis I.S. optical smoke detectors as general-purpose smoke detectors for early warning of fires in most areas, and notes they are particularly suitable for smouldering fires and escape routes.

What to confirm before ordering

Confirm which version you need (standard or flashing LED), order the mounting base ORB-MB-50018-APO separately, and verify the I.S. barrier and panel compatibility. The T4 and T5 ambient limits differ, so check the temperature class against the site. The datasheet describes design to IP44.

Hazardous-area approvals apply to the certified system, so confirm the certificate and marking for your zone and gas group. Apollo notes that conformity with the EMC Directive does not confer compliance on connected apparatus.

How the Apollo ORB-OP-52027-APO works

A small light source sends light into the sensing chamber. When smoke enters, it scatters the light, and the detector measures the scattered light at several angles, including backward. This helps with black smoke, which scatters less light forward. The detector samples every 4 seconds, and an algorithm decides when to raise the alarm.

Where the ORB-OP-52027-APO is used

• Intrinsically safe fire loops
• Areas with gas, Ex ia IIC
• Process plants
• Spaces with black and white smoke risk
• Marine and offshore spaces

Selection checklist for the ORB-OP-52027-APO

• Standard or flashing LED version
• Mounting base ORB-MB-50018-APO
• Loop voltage of 14.8 to 28 V dc
• Temperature class and ambient limit
• Interface or barrier for the loop
• Cable and polarity
• Remote output LED
• Number of detectors on the loop

Installation, commissioning and maintenance notes for the ORB-OP-52027-APO

Fit the base first and wire the two cores with the right polarity. Push the detector into the base. Watch the StartUp red flash that confirms the polarity. Test the detector with a smoke test. Clean the chamber on the schedule that the site plan sets.

Requesting a quotation for the Apollo ORB-OP-52027-APO

Please send the part number, the base and the quantity. Seven Star LLC serves industrial customers in Oman and the GCC and replies with a quotation based on the information provided.

ORB-OP-52027-APO part numbers

The standard detector is ORB-OP-52027-APO and the flashing LED version is ORB-OP-52028-APO.

ORB-OP-52027-APO supply

The operating voltage is 14.8 to 28 V dc on two wires, and polarity reversal is not allowed.

ORB-OP-52027-APO current

The quiescent current is 85 microamps at 24 V.

ORB-OP-52027-APO power-up

The power-up time is under 20 seconds.

ORB-OP-52027-APO alarm load

The alarm load is 325 ohm in series with a 1.0 V drop.

ORB-OP-52027-APO temperature range

The range is minus 40 to plus 70 degrees C, limited by gas class to T5 up to 45 degrees C and T4 up to 60 degrees C.

ORB-OP-52027-APO size and weight

The detector is 100 mm in diameter and 42 mm high, and weighs 75 g, or 135 g with the base.

ORB-OP-52027-APO materials

The housing is white flame-retardant polycarbonate and the terminals are nickel-plated stainless steel.

Detector records for the ORB-OP-52027-APO

Record the loop address, the location and the date of each test.

Choosing the right ORB-OP-52027-APO version

Choose the flashing LED version where the detector must show its alarm state at the head.

Documents and quotation

The manufacturer document for the ORB-OP-52027-APO is listed under Documents on this page: Apollo PP5037 Orbis I.S. Optical Smoke Detector technical data (Issue 3, 2026). Browse related items in Fire & Gas Detectors. For price, availability and lead time, send an RFQ with the exact part number, quantity and project details; Seven Star LLC is an independent supplier based in Muscat and confirms stock and delivery on quotation.