Sounders and beacons for fire and gas systems in Ex zones
19 November 2025
Integral to Fire and Gas (F&G) systems, sounders and beacons provide the visual and audible alerts needed to initiate an emergency response and evacuation. But when lives and infrastructure are at risk of explosion on an offshore platform or chemical plant, these devices cannot be the source of an ignition, further escalating a problem. Explosion protection specialist Mark Pemberton explains.
What are fire and gas safety systems?
F&G systems are critical safety barriers designed to detect hazardous events, such as fires or gas leaks, as early as possible, helping to prevent escalation that could lead to fatalities or significant asset damage. F&G detection is not just about technology, but about strategic placement and integration into broader safety systems to control escalation and protect both people and infrastructure.
Signalling devices for fire and gas safety systems
Alarms in fire and gas safety systems are triggered when a signal from an initiating device (manual or automatic) is sent to a central control panel, which then processes the information and activates the appropriate audible and visual devices. In F&G systems, rapid and clear communication is therefore essential.
The problem with standard, off-the-shelf beacons or sounders, is that they are a source of ignition from arcing or sparking components inside the device. So if they are used in an area where a flammable gas is present, they could then cause an explosion. Regulations help to control the use of products inside a “Zoned” hazardous area which leads fire and gas safety system specialists to select explosion proof variants that deliver the visual and audible alerts needed.
For example, Ex-tech Signalling’s explosion proof sounders and beacons are designed to deliver maximum visibility and audibility, ensuring that alerts are noticed even in noisy or visually cluttered industrial settings. For example, the BC125 and BC150 beacons offer LED and Xenon options with various intensities to suit the application, housed in robust stainless steel or GRP enclosures. These units are IP66/IP67 rated, making them suitable for both indoor and outdoor use.
ATEX/IECEx Sounders such as the SD125 provide powerful acoustic signals that work over noisy machinery, while combination units like the SB150-1 integrate both light and sound, suitable where mounting space is limited and a single connection point simplifies installation for less complex systems. These devices are often deployed as part of integrated F&G systems, connected to PLCs, ESD systems, or DCS platforms to trigger alarms automatically in response to sensor inputs.
In addition, the locations of manual call points and push buttons to manually trigger the alerts is also critical. Available in stainless steel or GRP housings to suit the application, Ex-tech Signalling devices are designed for durability and ease of use, particularly in emergency scenarios. These manual devices are crucial in F&G applications, allowing personnel to raise alarms instantly when automatic systems may not detect a threat or when immediate evacuation is necessary.
Ex signalling for fire and gas systems
Whether safeguarding offshore platforms, supporting energy transition operations such as hydrogen production or in a food or beverage industry, fire and gas safety system signalling plays a vital role in protecting people and infrastructure.
The examples below illustrate how Ex-tech Signalling’s certified devices are deployed in high-risk environments, where rapid alerts, reliable performance, and direct integration with safety systems are essential.
From corrosive offshore marine conditions to volatile hydrogen processes, signalling solutions must adapt to the unique challenges of each site. And in hazardous areas with the potential for explosive atmospheres, every component in the fire and gas safety system must be designed to prevent ignition.
Application Example
Fire and gas signalling for offshore platform
An offshore gas processing platform operating in the North Sea has designated classified hazardous areas due to the presence of flammable gases. The platform’s safety strategy includes a comprehensive fire and gas detection safety system designed to identify leaks, fires, and other hazardous events before they escalate.
The Challenge: The layout on the platform includes confined spaces, high ambient noise from machinery, and exposure to harsh weather conditions. The safety team needed signalling devices that could:
- Operate reliably in corrosive, salt-laden air
- Provide both visual and audible alerts in noisy environments
- Integrate directly with the platform’s Emergency Shutdown System (ESD)
- Minimise installation footprint due to limited mounting space
The Solution: Ex-tech Signalling supplies a number of ATEX-certified devices suited to the offshore conditions:
- SD125 Sounders: Installed in high-noise zones to ensure audible alerts are heard above machinery such as diesel generators, mud pumps and hoisting.
- BC 150 Status Lights: High-intensity visual alarms provide clear alerts in environments where noise levels or hearing protection may reduce the effectiveness of audible signals such on the drilling floor.
- Designed in GRP: Glass Reinforced Plastic housing option for ease of maintenance with salt spray
Integration: All devices were connected to the platform’s PLC-based F&G system. Upon gas detection or fire signal, the system automatically activated the relevant sounders and beacons, initiated ESD protocols, and alerted the control room.
Application Example
Fire and gas signalling for hydrogen production plant
As industries shift toward greener energy sources like hydrogen and synthetic fuels, the need for explosion protection is evolving. Ex-tech Signalling is actively supporting this transition by providing signalling solutions for new energy projects, ensuring safety in emerging applications where flammable gases and volatile processes are still present.
Challenge: Hydrogen is colourless, odourless, and highly flammable, making early detection and clear alerting essential. The plant’s safety team needed signalling devices that could:
- Deliver immediate, unmistakable alerts in both indoor and outdoor zones
- Withstand exposure to moisture, chemical vapours, and temperature extremes
- Integrate with the plant’s distributed control system (DCS) and emergency shutdown logic
- Minimise installation complexity across modular skids and compact control rooms
Solution: Ex-tech Signalling provided a tailored suite of signalling devices built for hydrogen, a IIC gas:
- SB150-1 combination units: Installed at key process areas and access points, these units provided synchronised light and sound alerts. Their compact footprint and single wiring point made them ideal for modular hydrogen skids.
- BC150 LED beacons and SD150 sounders: Used in open-air zones and near electrolyser stacks to ensure visibility and audibility in all conditions.
- CP125 manual call points: Positioned near control panels and emergency exits, allowing operators to manually trigger alarms in case of gas detection or fire.
Integration: All devices were linked to the plant’s DCS and F&G logic solver. Upon detection of hydrogen leaks or elevated temperatures, the system activated the signalling devices, initiated shutdown procedures, and alerted operators via HMI and remote monitoring systems.
For more information and support on integrating devices for fire and gas systems in hazardous areas, call +44 (0)1752 333 939, email sales@ex-techsignalling.com or visit https://ex-techsignalling.com/contact-us-ex-tech.
About the Author
Mark Pemberton – With over three decades in the electrical and safety industries, Mark has driven commercial and operational growth across global markets with Petrel and Ex-tech Signalling, key brands of the Pioneer Safety Group. His expertise in explosion protection, hazardous area compliance, and safety-critical infrastructure makes him a trusted voice for safety in fire and gas systems in Ex zones.
