What gases can YOURUIAN gas detectors measure?

Coverage of 600+ detection factors including H₂S / CO / CH₄ / O₂ / NH₃ / Cl₂ / SO₂ / NO₂ / VOCs / SF₆ / SiH₄ — common and specialty gases — supporting electrochemical, catalytic combustion, infrared, PID, thermal conductivity, and laser TDLAS sensing principles.

Are the products explosion-proof certified?

All fixed / portable / pump-aspirated core models pass Ex d ⅡC T6 Gb flameproof + Ex ia ⅡC T4 Ga intrinsic safety dual certification, with Explosion-Proof Certificates issued by the National Explosion-Proof Center, suitable for Zone 1/2 hazardous areas in petrochemical, gas, and coal mining sectors.

Can sensors and ranges be customized?

Yes. Customization is supported across gas type, range, enclosure material (aluminum / 304 / 316L stainless steel), communication interface (4-20mA / RS485 / Modbus / HART / LoRa / NB-IoT / 4G), alarm thresholds, and brand OEM. Standard products ship in 7 days; custom orders in 15–30 days.

What is the warranty period? How fast is on-site response?

12-month whole-unit warranty (sensor warranty calculated separately). Failure response within 24 hours; field engineer arrival within 48 hours. Paid extended warranty, maintenance contracts, and factory annual calibration (with certificate) available as long-term services.

Can the products integrate with existing DCS / SCADA / industrial IoT platforms?

Yes. All products come standard with 4-20mA + RS485 (Modbus RTU) + HART protocols, with optional LoRa / NB-IoT / 4G. The YOURUIAN proprietary IoT monitoring cloud platform also provides RESTful API + Webhooks for integration with EHS / MES / SCADA / industrial IoT platforms.

GB Limits & Alarm Threshold Calculator

Based on GBZ 2.1-2019 / OSHA NIOSH · industrial hygiene / explosion-proof / confined space — 3 rule sets one click

Select Gas

⚙️

Select a gas above and we'll auto-display the GB limits and 3 scenario alarm recommendations.
Based on GBZ 2.1-2019 (Occupational Exposure Limits for Hazardous Agents in the Workplace), covering 300+ common gases.

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📏 GBZ 2.1-2019 / OSHA NIOSH Limits

PC-TWA (Time-weighted average)	—	8-hour continuous exposure max
PC-STEL (Short-term exposure)	—	Not to be exceeded within 15 min
IDLH (Immediately Dangerous to Life or Health)	—	Max for 30-min escape window
LEL (Lower Explosive Limit)	—	Lower flammability limit in air
UEL (Upper Explosive Limit)	—	Upper flammability limit in air

🎯 Recommended Alarm Thresholds (by scenario)

Calculation Rules

Pre-alarm = PC-TWA × 0.5
High alarm = PC-STEL (if available) or PC-TWA × 1.0
Danger level = IDLH

Reference: GBZ 2.1-2019 (Occupational Exposure Limits for Hazardous Agents in the Workplace)

Pre-alarm coefficient 0.5

Level	Recommended	Notes

Calculation Rules

Pre-alarm = LEL × 10% (low alarm)
High alarm = LEL × 25% (high alarm)
Shutdown interlock = LEL × 50% (with PLC integration)

Reference: GB 50493-2019 (Combustible & Toxic Gas Detection Alarm Design Standard for Petrochemical)

Pre-alarm coefficient % LEL 10% High alarm coefficient % LEL 25%

Level	Recommended	Notes

Calculation Rules

Pre-alarm = IDLH × 10%
High alarm = IDLH × 50%
Immediate evacuation = IDLH

Reference: GB 8958-2006 (Safety Rules for Working in Oxygen-Deficient Spaces) + NIOSH Confined Space Best Practices

Level	Recommended	Notes

🖨️ Print / Save PDF

Need to deploy these thresholds on actual equipment? On-site survey / remote setup / PLC integration — one-stop service.

📞 Contact Engineer for On-Site Setup →

📌 Engineering Notes

Tool output is a recommended reference; final alarm thresholds must be adjusted per on-site risk assessment (ventilation, personnel density, emergency response plan).
For gases with both toxic and combustible risk (e.g. ammonia, carbon monoxide), apply the lower threshold.
Detectors must be calibrated with certified standard gas at minimum 3 concentration points before commissioning.
Toxic gas detectors: calibrate every 6 months. Combustible gas detectors: calibrate annually.