A gas detection system is a critical part of the wider Fire & Gas strategy on an oil and gas facility, but its lifecycle extends far beyond installation and commissioning.
From understanding the hazards and developing the Fire & Gas detection philosophy, through to detector selection, Fire & Gas mapping, system design, installation, commissioning, maintenance, calibration, performance review and eventual replacement, every stage can influence the effectiveness of the detection system.
For operators, engineers and those responsible for Fire & Gas systems, taking a lifecycle approach can help ensure that the detection strategy remains appropriate as the facility, equipment, process conditions and operating requirements change.
Protex (UK) Systems Ltd provides Fire & Gas consultancy, detection mapping, engineered Fire & Gas systems, package supply and engineering support across a range of detection technologies and applications, including challenging oil and gas environments.
What Is a Gas Detection System?
A gas detection system is designed to identify the presence of potentially hazardous gases and provide an appropriate warning, alarm or signal when defined detection criteria are met.
Depending on the application, a gas detection system may be designed to detect combustible gases, toxic gases such as hydrogen sulphide (H₂S), oxygen deficiency or other specific hazards associated with a process or facility.
A complete Fire & Gas system can incorporate gas detectors, flame detectors, controllers, panels, alarm devices, field equipment and interfaces with other site systems. The exact configuration depends on the hazards present, the process, the environment, the required detection performance and the Fire & Gas philosophy established during the design stage.
This is why selecting a gas detector should not be treated as an isolated purchasing decision. The detector needs to form part of an overall detection strategy designed around the hazards and requirements of the facility.
Understanding Gas Detection Requirements and Site Hazards
The gas detection system lifecycle begins with understanding what needs to be detected and, importantly, why.
Oil and gas facilities can contain a range of flammable and toxic substances. A release may occur under different process conditions and can behave differently depending on factors such as ventilation, equipment layout, release characteristics and the surrounding environment.
The detection strategy therefore needs to consider how a release could occur, how it could disperse and where people, equipment or processes could be exposed.
Factors that may need to be considered include:
- Flammable or combustible gases
- Hydrogen sulphide (H₂S)
- Other toxic gases
- Oxygen deficiency
- Potential gas release locations
- Process conditions
- Ventilation
- Environmental conditions
- Hazardous areas
- Personnel exposure
- Required detection performance
- The consequences of a potential release
This information provides the foundation for the Fire & Gas detection philosophy and the system design that follows.
A systematic, risk-based approach can help determine the quantity, type and positioning of detection equipment required for a particular application. Protex provides Fire & Gas consultancy to support engineering decisions around the selection and application of detection technologies.
Choosing the Right Gas Detection Technology
There is no single gas detection technology that is suitable for every oil and gas application.
Depending on the hazards, process conditions and environment, a Fire & Gas system may incorporate point gas detection, open-path gas detection, acoustic gas leak detection, flame detection or a combination of technologies.
Point Gas Detection
Point gas detectors monitor gas concentrations at specific locations.
They are available for a range of combustible and toxic gases and can form part of fixed gas detection systems and wider Fire & Gas control arrangements.
Point detection can be appropriate where the location of potential gas accumulation or release can be identified and where the detector can be positioned to provide the required level of protection.
Open-Path Gas Detection
Open-path gas detectors monitor a defined optical path between a transmitter and receiver.
This approach can provide area coverage and may be particularly useful across larger or more open process areas where point detectors alone may not provide the desired coverage.
Open-path infrared technology can form an important part of a wider gas detection strategy, depending on the application, site layout and detection objectives.
Acoustic Gas Leak Detection
Acoustic gas leak detection takes a different approach to conventional concentration-based gas detection.
A high-pressure gas release can generate airborne ultrasound. Acoustic gas leak detectors can detect the characteristic sound generated by a release without relying solely on gas reaching a conventional sensor or accumulating to a particular concentration.
This can make acoustic detection particularly relevant to suitable open, well-ventilated and high-pressure applications.
Protex provides acoustic gas detector area coverage verification and has factory-trained engineers with experience in the design, commissioning and area verification of acoustic gas leak detection systems.
Flame Detection
Fire detection can also form part of the overall Fire & Gas strategy.
Depending on the application, flame detectors and gas detectors may be used together to provide complementary detection capabilities across hazardous process areas.
The most appropriate combination of technologies depends on the hazards, process conditions, environment, required detection performance and overall Fire & Gas philosophy.
Selecting Gas Detection Equipment
With the detection philosophy and coverage requirements established, suitable gas detection equipment can then be selected.
Equipment selection should take account of the specific application rather than being based solely on the detector itself.
Factors may include:
- The gases or hazards being detected
- Detection technology
- Required detection range and performance
- Process conditions
- Hazardous area classification
- Temperature and environmental conditions
- Required response time
- Detector location
- Maintenance requirements
- System architecture
- Integration with existing Fire & Gas or control systems
- Availability of engineering and maintenance support
Protex works with a range of established Fire & Gas detection technologies and manufacturers, allowing equipment selection to be based on the requirements of the application.
The company’s product and system capabilities include acoustic gas leak detection, point and open-path gas detection, flame detection and a range of Fire & Gas control systems.
Designing the Fire & Gas Detection System
The detectors are only one part of the overall Fire & Gas system.
Depending on the application, a complete system may incorporate:
- Gas detectors
- Flame detectors
- Acoustic gas leak detectors
- Gas detection controllers
- Fire & Gas panels
- Addressable systems
- Point-to-point systems
- Alarm devices
- Field devices
- Interfaces with PLC or other control systems
These components need to operate together in accordance with the project requirements and the intended Fire & Gas philosophy.
System architecture will vary from project to project. A smaller installation may use a straightforward card-based system, while a larger facility may require an integrated addressable or PLC-based Fire & Gas system.
Protex’s engineers and partners have experience with both complex integrated addressable and PLC-based Fire & Gas systems and simpler card-based designs. The company states that its systems capability includes integrated Fire & Gas, gas panels, fire panels, addressable solutions and point-to-point systems.
Gas Detection System Installation and Commissioning
Once the system has been designed and supplied, installation and commissioning can take place in accordance with the approved project design, equipment requirements and applicable project procedures.
Installation needs to take account of the equipment specification, hazardous area requirements and the environment in which the equipment will operate.
Commissioning provides an opportunity to verify that equipment has been installed and configured correctly and that the system performs in accordance with the project requirements.
Depending on the system, commissioning and testing may include:
- Checking detector installation
- Verifying system configuration
- Testing detector responses
- Checking alarm indications
- Testing control panels
- Checking system interfaces
- Confirming relevant system functions
- Verifying signals through the Fire & Gas system
The exact commissioning requirements will depend on the equipment, manufacturer, project specification and applicable procedures.
Protex has factory-trained engineers capable of commissioning, servicing, calibrating and verifying a range of Fire & Gas systems for onshore and offshore applications.
Acoustic Gas Detection Commissioning
Acoustic gas detection systems require additional considerations during commissioning because detector performance can be influenced by factors such as background noise, equipment layout and process conditions.
Protex’s engineers are factory trained by Gassonic and have experience in the design, commissioning and area verification of acoustic gas leak detection systems.
Area coverage verification can be used to assess whether detector locations and set points meet the design requirements under representative process conditions.
Maintaining a Gas Detection System
Commissioning is an important milestone, but it is not the end of the gas detection system lifecycle.
Once a gas detection system is operational, ongoing maintenance is required to help ensure that equipment continues to perform as intended.
Gas detectors operate in environments where contamination, environmental conditions, physical damage and sensor ageing can affect performance.
Maintenance requirements should be established with reference to the manufacturer’s recommendations, site procedures, the operating environment and the history of the equipment.
Routine maintenance may include:
- Visual inspection
- Functional testing
- Calibration where applicable
- Preventative maintenance
- Fault investigation
- Sensor replacement where required
- Verification of system functions
Accurate maintenance records are also important. Over time, these records can help identify recurring faults, changes in sensor performance and components that may require attention or replacement.
Protex provides Fire & Gas Health Care Contracts covering servicing and support, with factory-trained engineers capable of commissioning, servicing, calibrating and verifying a range of Fire & Gas systems.
Gas Detector Calibration and Bump Testing
Calibration and bump testing are both important elements of gas detector maintenance, but they serve different purposes.
What Is a Gas Detector Bump Test?
A bump test is a functional check intended to confirm that a detector responds when exposed to an appropriate test stimulus or test gas, as applicable to the detection technology.
A bump test can be used to verify that:
- The detector responds
- The sensor or detection element operates
- The expected alarm is generated
- Associated alarm functions operate as intended
A bump test does not, by itself, confirm the accuracy of a detector’s measurement.
What Is Gas Detector Calibration?
Calibration involves checking and, where necessary, adjusting a detector’s response against a known reference.
For applicable gas detection technologies, calibration will normally involve an appropriate certified reference gas and equipment in accordance with the manufacturer’s requirements.
Calibration helps confirm that detector readings remain within the specified performance requirements.
Calibration intervals should not be treated as a single universal period for every gas detector. The appropriate frequency should take account of factors such as the manufacturer’s recommendations, site conditions, maintenance history and relevant site procedures.
Different detection technologies may also have different testing and calibration requirements.
For example, Protex provides support for acoustic gas leak detection systems, where specialist test and calibration equipment can be used for applicable Gassonic detectors.
Sensor Ageing and Gas Detector Replacement
Gas detector sensors and other system components can degrade over time.
The rate and nature of degradation depends on the sensor technology, operating environment and exposure conditions.
Different detection technologies have different characteristics. For example, catalytic bead sensors can be susceptible to poisoning, while electrochemical sensors can degrade as their internal components age. Infrared detectors use a different detection principle but can still be affected by contamination, ageing components or obstruction of the optical path.
Signs That a Gas Detector May Require Attention
Potential indicators include:
- Repeated calibration failures
- Sensor drift
- Recurring faults
- Inconsistent readings
- Physical damage
- Contamination
- Ageing components
- Increasing maintenance requirements
- Difficulty obtaining replacement parts
Where a sensor has reached the end of its useful life, replacement may be appropriate.
However, sensor replacement should not always be considered in isolation.
If controllers, field equipment or other parts of the Fire & Gas system are also becoming obsolete or difficult to support, it may be more appropriate to review the wider system.
When Should a Gas Detection System Be Upgraded?
There is no single age at which every gas detection system should be replaced.
Instead, the decision should be based on whether the existing system remains suitable for the facility and whether it can continue to be supported, maintained and operated effectively.
A gas detection system may warrant review where there are:
- Obsolete or unsupported components
- Difficulties sourcing spare parts
- Increasing maintenance requirements
- Recurring faults
- Changes to the process
- Changes to the site layout
- Changes to the gases or hazards present
- Changes to required detection coverage
- Changes to system integration requirements
- Changes in applicable project or site requirements
- Opportunities to improve detection using newer technology
An upgrade can also provide an opportunity to reassess the original Fire & Gas detection philosophy.
A facility can change considerably over its operational life. New equipment, altered processes, modifications to hazardous areas or changes in operating conditions may mean that the original detector arrangement is no longer the most appropriate solution.
Fire & Gas mapping and engineering consultancy can support this type of review by assessing whether the existing detection arrangement continues to meet the required detection strategy.
Protex provides Fire & Gas consultancy and mapping services to support the assessment and development of detection strategies and detector layouts.
Decommissioning and Replacing a Gas Detection System
Eventually, an existing gas detection system may need to be replaced or significantly upgraded.
This stage needs to be carefully planned so that the required level of protection is maintained throughout the transition.
Depending on the installation, replacement work could involve:
- Phased replacement
- Temporary detection arrangements
- Isolation of existing equipment
- Installation of new equipment
- Commissioning of the replacement system
- Testing and verification
- Updating relevant documentation
- Reviewing the Fire & Gas detection strategy
One of the key considerations is ensuring that removing obsolete equipment does not inadvertently create a gap in Fire & Gas protection.
Decommissioning should therefore be considered as part of the wider upgrade strategy rather than as an isolated activity at the end of the project.
A planned approach can also provide an opportunity to review detector coverage, technology selection, system architecture and maintenance requirements before the replacement system is installed.
The Complete Gas Detection System Lifecycle
A gas detection system should be treated as a safety-critical part of the wider Fire & Gas strategy throughout the life of a facility.
The lifecycle can be summarised as:
Specify → Design → Map → Select → Supply → Install → Commission → Maintain → Calibrate → Review → Upgrade → Decommission
Each stage contributes to the overall performance of the system.
A change to the process may require the detection philosophy to be reviewed. A change in detector technology may provide an opportunity to improve coverage. Increasing maintenance requirements may indicate that equipment is approaching the end of its useful life.
Taking a lifecycle approach helps ensure that these changes are considered as part of the wider Fire & Gas strategy rather than only after problems have developed.
Why a Lifecycle Approach to Gas Detection Matters
The performance of a gas detection system is influenced by much more than the individual detector.
Effective gas detection starts with understanding the hazards and establishing an appropriate detection philosophy. Detector technology and positioning then need to support the required detection objectives, while installation and commissioning provide the foundation for reliable operation.
Once the system is operational, maintenance, testing and calibration help support ongoing performance.
As the facility changes, the detection strategy may also need to change.
This could mean reassessing detector coverage, introducing a different detection technology, replacing individual detectors, upgrading the Fire & Gas control system or replacing the wider system.
A lifecycle approach helps connect all of these activities.
Overall
A reliable gas detection system starts with good design, but its performance depends on how it is managed throughout the life of the facility.
Understanding the hazards, establishing the Fire & Gas detection philosophy, selecting appropriate detection technologies and assessing detector coverage are all important parts of developing an effective gas detection strategy.
For oil and gas facilities, this may involve a combination of point gas detection, open-path gas detection, acoustic gas leak detection and flame detection, supported by an appropriate Fire & Gas control system.
Once operational, appropriate maintenance, testing and calibration help support continued system performance. As equipment ages or site requirements change, reviewing the existing detection strategy can help identify when individual sensors, system components or the wider Fire & Gas system may need to be replaced or upgraded.
Protex (UK) Systems Ltd provides Fire & Gas consultancy, Fire & Gas mapping, acoustic gas detector area coverage verification, Fire & Gas package supply and engineering support across a range of Fire & Gas detection technologies.
With experience across gas detection, acoustic gas leak detection, flame detection and Fire & Gas systems, Protex can provide independent advice based on the requirements of the application.
Whether you are planning a new gas detection system, reviewing an existing Fire & Gas installation or considering a system upgrade, Protex can provide consultancy, engineering and technical support at key stages throughout the system lifecycle.
