Products » Hazardous Zones

Pressure and Mass Flow Controllers for Hazardous Zones

CID1 & CID2 instruments for flow and pressure control

Photo of Alicat devices for hazardous locations

For processes rated Class I Division 2, or Class I Division 1, our certified meters and controllers deliver high accuracy as good as ± 0.5% of reading or 0.1% of full scale, and repeatability of ± 0.2% of reading and ± 0.02% of full scale. Alicat^® Scientific offers electronic C1D2 and C1D1 mass flow and pressure instruments for hazardous gas zones and can be used with up to 130 gases. Here is a breakdown of which build options and models are certified for each hazardous gas designation.

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Alicat products for hazardous gas atmospheres

Diesel and gas industrial electric generator in CID2 hazardous zone

Class I Div 2 meters and controllers for mass flow, liquid, and pressure

P-Series, M-Series, and L-Series devices can be built to perform safely in areas where explosive gases are a potential risk, such as Class I Division 2, or Zone 2 areas. This includes M/MC and MW/MCW mass flow instruments, L/LC Liquid flow instruments, and P/PC pressure instruments. Alicat devices built for C1D2 areas are marked as “-X” in recognition of the Ex safety method which is used. These -X device builds have the following restrictions:

Pluggable locking connections (IC, DB15, DB9) which cannot be connected or disconnected within the hazardous zone
Installation in IP54 (or higher) rated enclosure inaccessible during normal operation without the use of tools
Electronics are housed in aluminum cases
Legacy firmware affects accuracy and totalizer feature

More details on C1D2 certifications and requirements $

Class I Div 1 meters and controllers for mass flow, and pressure

Gas analysis CID1 hazardous location at oil processing plant

Alicat’s Class I Div 1 (and ATEX Zone 0, 1) certified instruments are intrinsically safe.

Intrinsically safe (IS) is a method of protecting equipment for hazardous locations by limiting electrical and thermal energy outputs to levels too low to ignite a flammable atmosphere.  Alicat’s intrinsically safe models, IS-Max, and IS-Pro are certified in North America, Europe, and internationally, so global operations can standardize their system architecture, and R&D processes can consistently repeat tests from any location.

More details on C1D1 certifications and requirements $

Mass flow meters and controllers For C1D1, Zone 0, or Zone 1 hazardous gas areas

Alicat Intrinsically Safe Mass Flow Controller

C1D1 mass flow controllers

Alicat Intrinsically Safe Mass Flow Meter

C1D1 mass flow meters

Class I Div 1 pressure controllers and gauges

Alicat Intrinsically Safe Pressure Meter

C1D1 pressure meters

Alicat Intrinsically Safe Pressure Controller

C1D1 pressure controllers

IS-Max™ mass flow controller vs other CID1 flow control methods

PARAMETERS

HAZARDOUS LOCATIONS REQUIREMENTS

ACCURACY

CONTROL MECHANISM

P&ID IMPACT

ARMORED ROTAMETER WITH MANUALLY ADJUSTED NEEDLE VALVE OR REGULATOR

Shows volumetric flow rate of calibration gas.

Safe for Zone 0, CID1 Mechanical components only

± 1 – 2% of FS on cal gas. Decreased accuracy on process gases like H₂, He, CO₂.

Manual adjustments are imprecise & require technician in hazardous zone.

Easy installation with no electrical barriers. Relatively small footprint.

THERMAL SENSOR MFC IN EXPLOSION-PROOF ENCLOSURE

Mass flow (only) calculated based on K factors.

Safety for hazardous gas areas depends on proper enclosure reassembly & purge validation

Typically ± 0.5 – 1.0% of setpoint

Integrated proportional control valve. ~500 ms to 2 seconds for setpoint changes.

Largest, most complex footprint. Requires purge lines, rated cable glands, tubing penetration.

ATEX ZONE 0 FLOW METER WITH EXTERNAL VALVE FOR FLOW CONTROL

Mass & volumetric flow, absolute pressure & temperature

Measurement only for Division 1 / Zone 1 or 0. Separate control valve required.

As good as ± 2% of full scale flow rate

Manually configure meter + valve control loop.

Meter and valve separated, with distinct cables, barriers. Potentially large footprint.

ALICAT IS-MAX™ MASS FLOW CONTROLLER

True mass flow & 12 other parameters. Optional RH sensor. Max of 2 totalizer counts running simultaneously

Measurement and control Class I Division 1 ATEX Zone 0 & 1 IECEx

As good as ± 0.1% FS or ± 0.5% of reading

Integrated proportional control: 30 ms response to new setpoint.

One device, barriers needed for each parameter + control input. Small footprint vs multi-instrument cluster.

ALICAT CLASS 1 DIV 2 MASS FLOW CONTROLLER WITH -X CONFIGURATION

True mass flow & 12 other parameters. 1 totalizer count only

Measurement and Control Class I Division 2 ATEX Class 1 Zone 2

As good as ± 0.2% FS or ± 0.8% of reading

Integrated proportional control: 30 ms response to new setpoint.

Locking cable connections required. Locking enclosure affects footprint size.

Alicat IS-Max offers the only fully integrated control solution for mass flow in areas where explosive gases are continuously present.

Triple certified for global use: Class I Division 1, ATEX Zone 0, IECEx

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Meet Mira: A hydrogen powered boat with an Alicat MCRQ mass flow controller

ATEX Zone 2 IIC certification, requires minimal additional safety infrastructure.
± 1.0% accuracy of reading (or ±  0.2% of full scale)
Upstream valve position, enables precise regulation of downstream feed pressure, supporting target values like the ~2.5 bar commonly seen in fuel cell stacks.
4 – 20 mA analog output for high-speed update rates (kHz range)

Sample pages of the eBook titled Automating CID1/Zone 0 Gas Processes

Modernize plant infrastructure while minimizing risk

In today’s hazardous‑area operations, the gap between efficient and legacy systems is widening. Operations that modernize instrumentation now gain advantages that could render these legacy systems obsolete.

Learn more about:

Multivariate flow and pressure control for analyzer integration in petrochemical processing
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