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The full Oxygen guide in gas detection

So what is the correct term — oxygen sensor or oxygen detector?
Both are completely correct; it just depends on what you mean.

An oxygen sensor is the actual sensing element that measures and responds to the gas.

An oxygen detector is the complete device, which includes the sensor along with the electronic system.

Some people also refer to a “nitrogen sensor” or “nitrogen detector.” In reality, there is no direct device for measuring nitrogen. What happens is that when nitrogen is present in an enclosed space, it displaces oxygen, and we measure how much the oxygen level drops.

That is exactly the purpose of an oxygen sensor or detector.

How much oxygen is in the air?
About 20.9%. The rest is mostly nitrogen, plus about 1% of other gases.

When is it important to know that oxygen levels are dropping?
According to safety standards, an alarm must be triggered at 19.5% oxygen — meaning only a 1.4% drop from normal air levels.

OSHA standards (29 CFR 1910.134 and 1910.146) define 19.5% oxygen as oxygen-deficient.

Yes, this may seem like a small drop. At 19.5% you can still breathe, but from that point, discomfort and shortness of breath can begin. As levels continue to decrease, the risk becomes severe — and below 14% oxygen, there is an immediate danger to life.

Is that a good enough reason to install an oxygen detector?
Absolutely. It can save lives.

Where should oxygen sensors/detectors be installed?

  1. The most common location is where nitrogen or liquid nitrogen cylinders are stored — in factories, laboratories, or storage areas.

  2. At the entrance to confined spaces — enclosed areas with limited ventilation. In these cases, workers should wear a personal portable oxygen detector, and if possible, a fixed wall-mounted detector should be installed for continuous monitoring.

Recommended Oxygen Detectors

Fixed Oxygen Deficiency Detector – Model TOC-750BAV

This is a standalone detector powered by 24V or 220V.

  • Dry contact relay alarm at 19.5% (as required by safety standards)

  • Built-in strong audible alarm

  • LED alarm indicator

  • Fault alarm indicator

  • Power indicator

  • RESET button to silence and reset the alarm

  • TEST button to check the detector

  • Supplied with calibration certificate and installation instructions

Oxygen Deficiency Detector for Rooms – TOC-750BAV

Example project:
Installation of an oxygen detector with a warning light outside the room.

The warning light includes:

  • Visual alarm

  • Audible alarm

  • Sign: “GAS ALARM”

Main advantage:
You can know if there is a nitrogen leak before entering the room.

Portable Oxygen Deficiency Detector – Model SGT-P

  • Rubber-coated for scratch protection

  • Small and compact

  • Easy to use

  • Certified for explosive areas (ATEX)

  • Water and dust protection (IP67)

  • Battery life up to 3 years (replaceable)

When oxygen drops to 19.5%:

  • Vibration alarm

  • Audible alarm

  • LED lights activate

Supplied with calibration certificate and user instructions.

Where to Install Oxygen Detectors?

Common installation areas:

  • Laboratories

  • Nitrogen cylinder storage rooms

  • Living spaces

  • Industrial production halls

  • Warehouses

  • Industrial facilities

Where Is It Most Important?

The most common place is where nitrogen gas cylinders are used.

Nitrogen leaks can quickly reduce oxygen levels.
Low oxygen can be dangerous to human life.

Can the Detector Connect to Fire Systems?

Yes.

  • Can connect to external systems (like fire alarm systems)

  • Uses dry contact relay output

Also:

  • Can work as a standalone unit

  • Can connect to a solenoid valve to shut off gas automatically

  • Can activate warning light + siren

  • Can control ventilation, AC, or open windows

Large Room – Do I Need Many Detectors?

If the room is larger than ~500 sqft, it is recommended to install multiple sensors.

At the entrance:

  • Install a gas controller with digital display

  • Shows oxygen levels from all sensors

This way, you know before entering if it is safe.

Alarm Level

  • Normal oxygen level: 20.9%

  • Dangerous level: 19.5%

All our detectors alarm at 19.5%.

Do I Need to Calibrate Before Installation?

No.
The detector comes pre-calibrated.
Just connect power and it is ready to use.

Detector Lifetime

All detectors have limited life.

  • Many brands: ~2 years

  • Our detectors: 5+ years lifetime

Where Is the Detector Made?

  • 100% made in the UK

  • Meets strict European standards:

    • EN50194:1

    • EN60335:1

Installation Height

  • Install at about 1 meter height (breathing zone)

  • Keep at least 1 meter away from heat sources or emissions

  • Can be installed in any direction

  • Do NOT install flat on the floor facing up

Why Choose Our Detector?

  • Long sensor life: 5–10 years

  • Made in UK 🇬🇧

  • Easy to install (can do it yourself)

  • Pre-calibrated – ready to use immediately

  • Full technical support and on-site calibration service

  • Available in stock for fast delivery

  • Professional installation available

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