Confined Space Safety: Why Choosing the Right Gas Detector Can Save Lives

In recent months, confined space accidents have occurred frequently, causing severe casualties. Statistics show that the vast majority of these accidents are due to lack of safety awareness and inadequate protective measures. In confined spaces, a single oversight or moment of luck can cost lives.

01. Case Warnings

August 11, 2025 – Zunyi, Guizhou: Two workers died after entering a cellar without approval, ventilation, or gas detection. A rescuer also entered without precautions, leading to more fatalities.

August 3, 2025 – Beijing: Two workers of a telecom company died from poisoning and suffocation inside a cable duct. 

August 6, 2025 – Beijing: Two workers fell into a septic tank and suffocated.

Common causes: no risk assessment, no gas detection, and violation of safety rules.

02. How to Identify a Confined Space

Confined spaces are not dangerous just because they are “small.” A space should be treated as high-risk if it meets these three features:

Enclosed/semi-enclosed: tanks, reactors, fermentation tanks, cellars, sewage wells, biogas tanks.

Limited entry/exit: narrow passages (<80cm), single-exit basements.

Poor ventilation: gases accumulate or oxygen is depleted.

03. Three Major Deadly Risks

Toxic gases: H?S (sewage wells, septic tanks), CO (incomplete combustion), NH? (cold storage, fertilizer plants). Inhalation can cause unconsciousness within seconds.

Oxygen deficiency: Below 19.5% O? causes dizziness; below 12% can be fatal. Common in silos and closed tanks.

Explosion hazard: CH?, propane, and other flammable gases can ignite at explosive concentrations.

04. Five Essential Safety Steps

Identify risks: Confirm confined space, set up “No Entry” signs.

Ventilation: Use blowers for at least 30 minutes (never use oxygen displacement).

Gas detection: Must test with a portable gas detector before entry.

Protective gear: Wear protective clothing, gas masks/SCBA, and safety harness.

On-site monitoring: Dedicated supervisor outside, re-test every 30 minutes, stop work immediately if alarm triggers. Never work alone.

05. Choosing the Right Gas Detector

Confined spaces have complex risks. Selecting the right instrument for your application is critical. Our portable detectors offer tailored solutions:

Single Gas Detector – MS104K-S

Detects toxic gases such as O?, H?S, CO, or Cl? with high sensitivity. Compact and lightweight, IP67-rated, suitable for harsh environments. Rechargeable or maintenance-free versions available.

Four-in-One Detector – MS104K-M

Simultaneously detects combustible gases, O?, CO, and H?S. Features audible, visual, and vibration alarms, with optional pump for confined space entry. Wide temperature range (-25℃ to 55℃), IP66-rated for tough conditions.

Multi-Gas Detector – MS400-S

Supports up to 4 gases, including combustibles, oxygen, and toxic gases. Equipped with gravity-sensing high-brightness display, strong anti-EMI design for stable readings, and rugged housing (TPC+PC). IP66 protection, ideal for industrial operations.

Detection by type:

Toxic gases: H?S, CO, Cl?, etc., with 0.1ppm resolution, giving early warnings before human senses react.

Combustibles + Oxygen: Detects CH?, propane, and O? levels, preventing explosion and asphyxiation risks.

06. Conclusion

In confined space work, “luck” equals “risking lives.” Always remember:

? No detection, no entry.

? No ventilation, no entry.

? No monitoring, no entry.

With MS104K-S, MS104K-M, and MS400-S portable gas detectors, you can effectively eliminate hidden dangers at the source. Safety is never a small matter—detection comes first, protection follows.