Question 1

Is the Lower Explosive Limit (LEL) the same as the alarm setpoint?

Accepted Answer

No. LEL is the minimum concentration at which a gas can ignite; for methane it is about 5% by volume, which equals 100% LEL on the detector scale. Alarm setpoints are set well below it, typically at or below 25% LEL for the first-level alarm, according to the local code that governs the project.

Question 2

Where should a household combustible gas detector be installed?

Accepted Answer

Mount according to gas density: for natural gas (methane, lighter than air) install high, close to the ceiling; for LPG (heavier than air) install low, close to the floor. Keep the detector within a few metres of the appliance and away from extractor hoods, steam and direct airflow.

Question 3

Why do oxygen detectors use %VOL instead of ppm?

Accepted Answer

Normal air contains about 20.9% oxygen by volume, so oxygen deficiency and enrichment are tracked as volume percentages. Common reference alarm points are 19.5% VOL for deficiency and 23.5% VOL for enrichment, which are far easier to read and configure in %VOL than in hundreds of thousands of ppm.

Question 4

Can a Shield gas detector shut off the gas supply automatically?

Accepted Answer

Yes. Shield household detectors drive a solenoid valve when the alarm setpoint is reached, and the JYFJS-011 emergency shut-off valve can be triggered by gas alarm systems, fire-protection panels or smart terminals. The valve must be reopened manually so gas cannot return before the hazard is cleared.

Question 5

What is the difference between a stand-alone and a bus-type point gas detector?

Accepted Answer

A stand-alone detector such as the SD2130 series alarms locally and drives linkage outputs without a controller, ideal for single zones. Bus or branch-line detectors such as the SD2100A series report to a gas alarm controller (SD8001A/B) installed in a non-hazardous control room for centralized multi-point monitoring.

Question 6

Does Shield offer OEM and ODM gas detectors?

Accepted Answer

Yes. With 80+ marketable product models and in-house R&D, Shield supports private labelling, housing and packaging customization and configuration changes for distributors and brand owners. Request the catalog to review available platforms.

OEM Industrial and Commercial Gas Detector Shield SD2130 Series Manufacturers, Supplier

High-Quality Industrial and Commercial Gas Detector Shield SD2100E Series Manufacturer, Factory

ODM Industrial and Commercial Gas Detector Shield SD2100A Series Manufacturer, Factory