GS8400-LEL Fixed Combustible Gas Detector
Catalytic bead LEL detector for explosion prevention
- Range
- 0-100 %LEL
- Accuracy
- ±3% LEL
- Rating
- ATEX Zone 0, SIL 2
- Sensor Life
- >4 years
Overview
Fixed-point combustible gas detector using catalytic bead sensor for continuous %LEL monitoring. Poison-resistant catalyst with extended service life for petrochemical environments.
- ATEX Zone 0 certified (highest rating)
- Poison-resistant catalyst formulation
- Hot-swap sensor replacement
- SIL 2 functional safety
Full Technical Specifications
Key Performance
| Metric | Value | Status |
|---|---|---|
| Range | 0-100%LEL | confirmed |
| Accuracy | ±3% LEL | confirmed |
| Response | <10 s T90 | confirmed |
| Safety Rating | ATEX Zone 0, SIL 2 | confirmed |
| Sensor Life | >4 years | confirmed |
Measurement
| Specification | Value |
|---|---|
| Measuring Principle | Catalytic Bead (pellistor) |
| Measurement Range | 0–100 %LEL |
| Accuracy | ±3% LEL |
| Response Time (T90) | <10 s |
| Resolution | 1% LEL |
Physical
| Specification | Value |
|---|---|
| Dimensions (W×H×D) | 170 × 175 × 110 mm |
| Weight | 2.1 kg |
| Housing Material | 316SS Ex d flameproof, IP66 |
| Mounting | Wall/pipe mount, 3/4″ NPT entries |
Electrical
| Specification | Value |
|---|---|
| Power Supply | 24 VDC (18–32 VDC), loop-powered |
| Analog Output | 4–20 mA with HART 7 |
| Relay Outputs | 2 × SPDT alarm relays |
| Power Consumption | <4 W |
Environmental
| Specification | Value |
|---|---|
| Operating Temperature | -40 °C to +65 °C |
| Humidity | 0–99% RH |
| Ingress Protection | IP66 |
| Vibration | IEC 60068-2-6 |
Certifications
| Specification | Value |
|---|---|
| ATEX | II 1G Ex d IIC T6 Gb (Zone 0) |
| Functional Safety | SIL 2 per IEC 61508 |
| Performance | EN 60079-29-1 |
| Marine | DNV GL type-approved |
Where This Analyzer Fits
This model is mapped to the following industry applications and process duties.
Deployment Environments
Common process environments where this model is evaluated.
Certification Scope
Standards are listed with scope and status so engineering review can verify the applicable enclosure, area, and safety case.
| Standard | Scope | Variant | Status | Document |
|---|---|---|---|---|
| ATEX II 1G Ex d IIC T6 Ga | Zone 0 fixed combustible-gas detector installation | Project variant | approved | On request |
| IEC 61508 SIL 2 | Functional safety rating stated in key specs, specifications, and certification detail | Project variant | approved | On request |
| EN 60079-29-1 | Combustible gas detector performance standard listed in specifications and certification detail | Project variant | approved | On request |
| IECEx / CSA / FM / UKCA / INMETRO | Approvals listed in existing certification detail | Project variant | approved | On request |
| IP66 | Ingress rating listed in specifications and certification detail | Project variant | approved | On request |
Request Documentation
Request technical datasheets, user manuals, certificates, and application notes for this model.
Evidence Notes
Fixed %LEL detector architecture for coastal petrochemical duty
Application note based on the existing petrochemical scenario: catalytic-bead %LEL detection with poison-resistant catalyst formulation and hot-swap sensor replacement supports combustible-gas safety coverage in coastal plant areas. Fleet maintenance depends on inhibitor exposure, calibration-gas practice, and site proof-test policy.
Technical & Engineering Details
Secondary engineering detail — expand each topic for the full measurement, envelope, sample-system, calibration, integration, maintenance and application evidence.
01 Measurement Principle and Limits
How the measurement is bounded
Catalytic bead pellistor detects combustible gas by catalytic oxidation for fixed-point %LEL safety monitoring.
Rejects
- Process hydrocarbon concentration and hydrogen purity analysis duty
Requires
- Methane in air at 50% LEL as the standard reference gas
- Application-specific calibration gas and response factor for propane, butane, hydrogen, or other target gases
- Sensor-replacement workflow through the hot-swap sensor design
Interferents and Limits
- Silicones, lead, and sulfur compounds can deactivate catalytic bead elements
- Hydrogen %LEL safety duty requires gas-specific response-factor review
02 Operating Envelope
Use these limits as selection inputs, then confirm sample condition, ambient exposure, and materials before quotation.
- Process concentration measurement outside %LEL safety duty
- Oxygen-depleted environments without detector-technology review
03 Sample System Boundary
Sampling mode, conditioning components, and exclusions define where the analyzer responsibility ends and the sample system begins.
- Fixed-point flameproof detector at the monitored location
- Diffusion sensing at the catalytic bead; no extractive conditioning train
- No external extractive conditioning system is declared for this fixed safety detector
04 Calibration & Validation
Calibration method, interval, and traceability are shown only when structured data is available.
Zero / Span Method
Methane in air at 50% LEL (2.5% v/v CH₄) as the standard reference; application-specific calibration gas with response factor for other target gases
Interval
Bump-test and proof-test interval to be set by the site functional-safety procedure
Span Gas Traceability
Application-specific calibration gas review for target gases such as methane, propane, butane, or hydrogen
05 I/O & Integration
Signal outputs and communication interfaces shown from the published specification fields on this product page.
Analog Output
4–20 mA with HART 7
Relay Outputs
2 × SPDT alarm relays
DAHS Review Note
Confirm protocol map, channel naming, alarm states, and reporting format during project integration review.
06 Maintenance & Spares site-specific
Tasks, consumables, and access items are shown only when structured maintenance data is available.
- Bump-test and proof-test interval to be set by the site functional-safety procedure
- Hot-swap sensor replacement through the quick-disconnect bayonet workflow
- Poisoning-risk review where silicones, lead, or sulfur compounds may reach the catalytic bead
- Application-specific calibration gas review for target gases such as methane, propane, butane, or hydrogen
- Catalytic bead sensor head
- Methane in air at 50% LEL or application-specific calibration gas
07 Application Evidence
Application context from complex industrial environments.
Application Context
Petrochemical complexes commissioning new propylene plants in coastal environments need 100+ LEL detectors that survive salt-air corrosion and silicone vapors — duty profiles that historically poison standard catalytic-bead sensors within months.
Architecture Response
GS8400-LEL with a poison-resistant catalyst formulation maintains accuracy across multi-year service in coastal duty, and hot-swap sensor replacement keeps maintenance windows short across the full detector fleet.
Frequently Asked Questions
What does ATEX Zone 0 certification mean?
Zone 0 is the most hazardous classification where explosive gas is present continuously or for long periods. The GS8400-LEL uses a flameproof (Ex d) enclosure tested for worst-case internal explosion containment.
What is sensor poisoning and how is it prevented?
Certain compounds (silicones, lead, sulfur) can permanently deactivate catalytic bead elements. The poison-resistant catalyst uses a proprietary rare-earth formulation that resists common inhibitors.
How does hot-swap sensor replacement work?
The sensor head is mounted in a quick-disconnect bayonet fitting. Twist and pull to remove, insert replacement — no tools, no enclosure disassembly, no gas-free certificate needed.
What calibration gas should I use?
Methane in air at 50% LEL (2.5% v/v CH₄) is the standard reference. For specific target gases (propane, butane, hydrogen), use application-specific calibration gas with the appropriate response factor.
Does it detect hydrogen?
Yes, catalytic beads respond to all combustible gases including hydrogen. For hydrogen-specific applications requiring faster response, consider the GS8410-LEL with IR detection.
Related & Alternatives
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When this model is preferred
Select GS8400-LEL when its measurement principle, range, and form factor match the process duty and certification scope.
When to consider an alternative technology
Consider another analyzer when the gas matrix, sample temperature, hazardous-area scope, or reporting requirement falls outside the stated envelope.
Review GS8400-LEL against site conditions
Send gas range, sample temperature, pressure, moisture, and certification needs before final model selection.