The MUNI MP420 is a compact and lightweight 4-gas detector for worker safety at hazardous locations, with four standard sensors for oxygen (O2), combustibles (LEL), carbon monoxide (CO) and hydrogen sulfide (H2S). Alternative sensors are lead-free oxygen (O2), low-power infrared methane (CH4), sulfur dioxide (SO2), and hydrogen cyanide (HCN). The detector is packaged in a robust housing with no moving parts. Its battery power offers 24 hrs for a standard 4-gas detector, and extended runtime when using a low-power infrared sensor. The simple, 2-button operation results in ultimate ease of use and significantly reduced time spent training the user.

Product Features

Compact, robust, lightweight & wearable
Auto backlit LCD with large numeric digits
Easy-to-navigate menu with two buttons
Battery operation 24 hours with pellistor LEL sensor extended time with low-power infrared LEL sensor
Tri-color status indicators on regular self-diagnosis of sensor, battery and circuit
Wide angle LED alarms
1000 Events log
Combination charge adapter / micro-USB PC interface cable
IP-68 weather ingress rating
Optional BLE wireless connectivity
Optional MuniDock for convenient bump & calibration
Up to 4 factory-configured sensors selected from 8 sensor options

Sensor	Range	Resolution	Response Time (t₉₀)
1. Combustible (LEL) Pellistor NDIR	0-100%LEL 0-100% LEL CH₄	1%LEL	15 sec 30 sec
2. Oxygen (O₂) Galvanic Lead-free	0-30%Vol	0.1%Vol	15 sec
3. Hydrogen Sulfide (H₂S) or Hydrogen Cyanide (HCN)	0-100ppm 0-50ppm	0.1ppm 0.1ppm	15 sec45 sec
4. Carbon Monoxide (CO) or Sulfur Dioxide (SO₂)	0-1000ppm 0-20ppm	1ppm 0.1ppm	15 sec30 sec

Sensor

Range

Resolution

Response Time (t₉₀)

1. Combustible (LEL)

1%LEL

2. Oxygen (O₂)

0-30%Vol

0.1%Vol

15 sec

3. Hydrogen Sulfide (H₂S) or

Hydrogen Cyanide (HCN)

0-100ppm

0-50ppm

0.1ppm

15 sec45 sec

4. Carbon Monoxide (CO) or

Sulfur Dioxide (SO₂)

0-1000ppm

0-20ppm

1ppm

0.1ppm

15 sec30 sec

Size	4.33 x 2.36 x 1.10 in (110 x 60 x 28 mm)
Weight	8 oz (230 g)
Sensor	Standard LEL (Pellistor), O₂, CO and H₂S Alternatives CH₄ (NDIR*), O₂ LF (Pb-free†), SO₂ and HCN
Battery	Rechargeable Li-ion pack: ≥ 24 hours (with Pellistor) or extended run time (with NDIR)
Direct Readout	Real-time reading of gas concentration Visual compliance indicator Battery status STEL, TWA, peak and minimum values
Display	Segment LCD, 1.75 x 1.25 in (44 x 32 mm) with LED backlight for enhanced readability
Keypad	2 operation keys
Calibration	Manual calibration. MuniDock option allows automatic bump test and calibration
Alarm	Wireless remote alarm notification, audible (90dB@750px), vibration, visual (flashing bright red LEDs), and on-screen indication of alarm conditions Man Down Alarm with pre-alarm and real-time remote wireless notification
Datalogging	1000 Events (alarms, function tests and calibrations)
Charging and Communication	Charging with AC adapter or cable to PC PC comm for data download, monitor setup & firmware upgrades via cable, optional BLE (Bluetooth Low Energy), or MuniDock
Temperature	-4° to 122°F (-20°C to 50°C)
Humidity	0% to 95% relative humidity (non-condensing)
IP Rating	IP-68
Safety Certifications	UL/cUL: Class I, Div 1, Group A, B, C, D T4, -20°C ≤ Tamb ≤ +50°C EMC/RFI EMC directive: 2004/108/EC
Warranty	2-year including sensors