Multigas Quality Monitoring System
Gas Guardian
Most breathing air systems can tell you the air was clean on the day someone tested it. A sample goes away, results come back, a certificate goes in a binder. Between those tests, nobody knows what the air is.
The Nardi Gas Guardian closes that gap. It monitors compressed breathing air continuously, alarms on the gases that matter, and can shut the compressor down rather than only warn the operator. Every reading is logged, so air quality becomes a record rather than an assurance.
What It Monitors
Sensors are modular, so a system carries the ones that matter for the work it does and can be expanded later. Alarm thresholds are user adjustable to match local or site specific limits.
Carbon Monoxide (CO)
0 to 1000 ppm
Carbon Dioxide (CO2)
0 to 10,000 ppm
Oxygen (O2)
0 to 100%
VOCs and Oil Vapour
0 to 40 ppm
Hydrogen Sulphide (H2S)
0 to 100 ppm
Water Vapour, Dew Point
+20 C to -75 C
Helium, Optional Sensor
0 to 100%
The analyzer stabilises pressure at 50 bar (725 psi) before reading and validates flow at 2 L/min, so the numbers on the screen are measured under controlled conditions rather than sampled off a moving system.
Three Versions
The sensor block is the same in every version. What changes is how it is mounted and powered.
Integrated
Factory fitted into a Nardi Pacific high pressure compressor and powered from the machine. The sensor block sits inside the unit and the readout appears on the compressor control panel.
Fixed
Wall mounted display panel for aftermarket installation on an existing system. Adds continuous monitoring to a compressor already in service without replacing it.
Portable
Built into a rugged water resistant case for moving between sites and systems. Suited to an operation running more than one fill point, or to verification work across multiple locations.
The Hardware
Standards
The Gas Guardian is calibrated to EN 12021, the most demanding international standard for breathable air, and supports the standards in use across the major markets.
For Canadian operators. A CSA Z180.1 air test certificate is a snapshot in time. It shows the air met the standard on the day the sample was taken. Tests are months apart, so what happened to the air in between? How do you know every cylinder you filled since the last test was good? The Gas Guardian answers that. It reads the air continuously while the compressor runs, alarms on carbon monoxide and VOCs, and logs every reading, so the months between tests are on record too.
Breathing air limits, side by side
Every major standard agrees on which contaminants matter. They disagree on how much is allowed. This is where the Canadian and United States fire service limits sit against the European standard the Gas Guardian is calibrated to.
| Parameter | EN 12021:2014 Europe | CSA Z180.1:19 Canada | NFPA 1989:2019 United States fire service | CGA G-7.1 Grade E |
|---|---|---|---|---|
| Oxygen % by volume | 21 +/- 1 (20 to 22) | 20 to 22 | 19.5 to 23.5 | 20 to 22 |
| Carbon monoxide CO | 5 ppm max | 5 ppm max | 5 ppm max | 10 ppm max |
| Carbon dioxide CO2 | 500 ppm max | 600 ppm max | 1,000 ppm max | 1,000 ppm max |
| Oil and condensed hydrocarbons | 0.5 mg/m3 max | 1 mg/m3 max | 2 mg/m3 max | 5 mg/m3 max |
| Water vapour | Dew point at least 5 C below the lowest expected temperature. 35 mg/m3 max above 200 bar. | At or above 15.3 MPa: dew point -53 C, or 27 ppm max | 24 ppm max, about -54 C dew point | Not specified by the grade |
| Odour and taste | Free from unsatisfactory odour or taste | No pronounced odour | Not pronounced | None |
Scroll the table sideways to see every column.
What this means for a Canadian fire department. The Gas Guardian is calibrated to EN 12021, which is the tightest column in this table on carbon dioxide and on oil, and matches CSA Z180.1 and NFPA 1989 on carbon monoxide. Factory alarm points are set at 5 ppm CO and 500 ppm CO2, so a unit running inside its EN 12021 alarm band is also inside the CSA Z180.1 and NFPA 1989 limits for those two gases.
Editions cited. EN 12021:2014, CSA Z180.1:19 (reaffirmed 2025), NFPA 1989 (2019 edition), CGA G-7.1 (2018, seventh edition). Limits are summarised here for guidance. The published standard governs in every case, and quarterly or scheduled third party air testing is what demonstrates compliance.
Technical Specification
Routine calibration is operator friendly and does not require the unit to go back to the factory. Oxygen and dew point recalibrate autonomously. The remaining gases calibrate from supplied sample cylinders, mixed gas for CO, CO2 and VOC, with dedicated cylinders for O2 and H2S, at a flow rate of 2 L/min.
| Maximum inlet pressure | 420 bar (6,092 psi) |
|---|---|
| Operating temperature | +5 C to +45 C |
| Storage temperature | -10 C to +45 C |
| Operating humidity | 0 to 80% RH |
| Altitude limit | 2000 m (6,562 ft) |
| Enclosure | Anodised aluminium and stainless steel |
| Interface | Touchscreen with visual readouts and diagnostic data |
| Connectivity | IoT enabled for remote monitoring and data logging |
| Sensor life | 2 to 10 years depending on gas type |
| Country of origin | Italy |
