Gas Detection • HVAC Safety • Demand-Controlled Ventilation
Smart Gas Detection for Critical Environments
Critical Environment Technologies (CET) gas detection systems make commercial and industrial facilities safer and code-compliant: available through ChopAir, your hands-on HVAC manufacturer’s representative that designs, specs, and supplies complex HVAC systems.
The CET Product Lineup
Five categories. One complete system.
CET builds every component of a gas detection system: the sensors that detect, the controllers that respond, and the peripherals that alert. Everything is designed to work together and integrate with your building’s existing BMS or VFD infrastructure.
Controllers
The brain of a CET gas detection system. Controllers centralize monitoring, manage alarm logic, and drive ventilation or shutdown outputs, all from one panel. Built for integration with BAS, Modbus®, and BACnet® networks, and configurable for single-zone or multi-zone facilities.
Key Models
FCS Multi-Channel cGas-SC Self-ContainedGas Detectors & Sensors
CET’s core detection hardware covers the full spectrum of toxic, combustible, refrigerant, and asphyxiant gases. Sensors use electrochemical, catalytic bead, infrared (IR), and photoionization technologies, matched to the specific gas profile of each environment.
Detection Technologies
Electrochemical Catalytic Bead Infrared (IR) PhotoionizationRemote Devices & Peripherals
A complete system goes beyond detection. It communicates alarms, extends coverage, and gives operators visibility from anywhere in a facility. CET’s peripheral lineup covers everything from network-distributed relays to visual and audible alarm devices.
Key Devices
RSH Remote Strobe & Horn RDM Remote Display RSL Stack Light RLY-4 / RLY-8 Relays LNK-AO Analog Output LNK-XT Network Extender RPS-24VDC Power Supply RSW Remote SwitchSpecialty Products
Some installations require detection in locations where standard wall-mount sensors can’t reach: shafts, ceiling plenums, pits, vent stacks, and remote confined spaces. CET’s specialty line solves these challenges without compromise.
Key Models
cGas-SD Sample Draw System PRU-24-A Sample Draw Pump Ammonia Vent Line TransmitterAccessories & Options
Mounting hardware, weatherproof enclosures, junction boxes, calibration equipment, and configuration accessories that complete the installation and simplify ongoing maintenance. Instead of relying on aftermarket workarounds, CET designs their own accessories from the ground up.
Includes
Mounting Hardware Weatherproof Enclosures Calibration Tools Wiring AccessoriesNot sure which products your project needs?ChopAir engineers review your specs and help you build the most efficient system possible.
Where CET Is Specified
37+ environment types. One manufacturer.
CET takes an application-first approach. Every environment has its own gas hazard profile, code requirements, and sensor placement logic. Here are the major categories ChopAir clients commonly work with.
Parking & Vehicle Exhaust
Enclosed garages, loading docks, vehicle service bays, car dealerships, fleet depots, transit terminals, and emergency vehicle bays. Drives demand-controlled ventilation to cut fan runtime and energy costs.
Industrial & Mechanical
Boiler rooms, wastewater treatment facilities, welding and fabrication shops, waste and recycling plants, and warehouses with powered industrial equipment.
Refrigeration & Cooling
Chiller rooms, cold storage warehouses, mechanical plant rooms, data center cooling infrastructure, and ice arenas. Prevents costly refrigerant loss and ensures ASHRAE 15 compliance.
Food & Beverage
Breweries, wineries, distilleries, commercial kitchens, and cold storage. Monitors CO₂ buildup from fermentation, ethanol vapor in distilleries, and ammonia refrigeration systems.
Healthcare & Education
Hospitals, MRI suites (helium/O₂ monitoring), laboratories, schools, and indoor air quality monitoring for offices and public assembly spaces.
Recreational Facilities
Indoor pools and aquatics centers, ice arenas, hotels with VRF systems, and fitness centers. Multiple overlapping gas hazards often require several detector types in a single venue.
Charging & Battery Systems
EV charging stations, battery energy storage systems (BESS), forklift charging rooms, and data centers with battery backup. An increasingly important category as electrification expands.
Indoor Agriculture
Cannabis grow rooms, vertical farms, greenhouses, and CO₂ enrichment environments where gas levels are intentionally elevated and must be carefully bounded for safety.
Have a specific facility type in mind?ChopAir works through your application requirements and matches CET product configurations to your environment and local codes.
Gas Detection Coverage
40 gases. Every hazard profile covered.
CET sensors cover the full range of gases found in commercial and industrial HVAC environments, from common toxic exposures to the latest low-GWP A2L refrigerants now entering the market as R-410A is phased out.
Toxic Gases
Acute poisoning and chronic exposure risks in occupied and working spaces.
Combustible Gases
Fire and explosion prevention with continuous LEL monitoring.
Asphyxiants
Oxygen displacement monitoring for confined and semi-confined spaces.
Traditional Refrigerants
HFC, HCFC, and CFC detection for existing systems still in service across commercial and industrial facilities.
A2L Refrigerants
New low-GWP mildly flammable refrigerants replacing R-410A under updated EPA regulations.
The Operational Case for CET
Why Smart Gas detection is essential
Meeting code is the minimum. Smart gas detection saves lives and makes your utility use more efficient.
Demand-Controlled Ventilation: Fans Run When Needed, Not Always
Standard practice in most parking garages is to run exhaust fans 24/7 or on a fixed schedule, regardless of whether there’s actually a CO or NO₂ problem. CET sensors feed real-time gas data to VFDs and fan controllers, triggering ventilation only when thresholds are crossed. The result is dramatically lower energy consumption, less mechanical wear, and a system that responds to actual conditions rather than assumptions. For facility managers, this is one of the fastest payback applications in building infrastructure.
Refrigerant Loss Detection: Protect a Costly Chemical Charge
Modern refrigerants are expensive, and slow leaks drain a system’s charge long before the performance degradation becomes obvious. CET’s infrared (IR) sensors catch refrigerant concentrations early, allowing maintenance to intervene before a full recharge is needed. For construction managers specifying new chiller or VRF infrastructure, IR-based refrigerant detection built into the design stage is far cheaper than a reactive retrofit after the system is commissioned.
Plug & Play Sensor Replacement: End the Rewiring Tax
All gas sensors drift and degrade over time. In a traditional fixed detector, replacing a sensor means taking down the transmitter, rewiring, and recalibrating, a process that’s time-consuming and often deferred until the sensor fails outright. CET’s Plug & Play Smart Sensor Technology separates the sensor board from the transmitter housing, allowing board-level swap-outs in minutes without touching a single wire. For facility managers running multi-zone detection across a large building, this changes the economics of preventive maintenance.
Code Compliance by Design: IMC, CMC, ASHRAE 15, EPA
Gas detection requirements across IMC, CMC, ASHRAE 15, and EPA refrigerant regulations are not static, and the stakes for non-compliance are real: failed inspections, regulatory violations, insurance implications, and in serious cases, occupant health incidents. For construction managers, specifying code-compliant CET systems during design eliminates the costly scramble of a pre-occupancy correction. For facility managers, continuous monitoring maintains a documented record of compliance between audits.
A2L Refrigerant Readiness: Detect What’s Coming, Not Just What’s Here
As R-410A phases out under updated EPA regulations, the commercial HVAC industry is transitioning to A2L refrigerants like R-32, R-454B, R-1234yf, and R-1234ze. These refrigerants are mildly flammable, a classification that creates new detection requirements under ASHRAE 15 and building codes that didn’t previously apply. CET already has sensors for all four A2L refrigerants in commercial use. For teams specifying new systems today, this is forward-looking protection built into the product catalog.
Why This Partnership Exists
Why ChopAir chose CET
ChopAir only represents manufacturers that meet a high bar: quality hardware, strong factory support, and teams that treat their rep partners like partners. CET checks every box.
30+ Years of Focused Expertise
CET has been building gas detection hardware since the early ’90s. They don’t make anything else, which means they are entirely focused on getting this one category right.
A Team That Actually Answers
CET works on a phone-call basis, so when a project has a question or a job site has a problem, ChopAir can reach CET directly and get answers fast.
Hardware Built for the Field
CET products are all designed around the practical realities of installation, maintenance, and long-term performance in commercial facilities.
BAS & BMS Integration Ready
CET controllers support Modbus® and BACnet® out of the box, easily integrating with the building automation systems that ChopAir clients already run.
Working With ChopAir
Get Turnkey Gas Detection Systems With ChopAir
ChopAir is a hands-on HVAC manufacturer’s representative serving commercial and industrial clients. We don’t just quote product and supply equipment. We’re your project partners from design & engineering to specification and delivery, making sure what gets ordered actually makes sense for what’s getting built.
Spec Review & Product Selection
ChopAir reviews your project requirements and helps identify the right CET products, including detectors, controllers, and peripherals, matched to your application, gas profile, and code requirements.
Project Coordination
From the first quote through final delivery, ChopAir stays involved, coordinating lead times, equipment staging, and order arrival to avoid surprises on the job site.
Manufacturer Access
When you work with ChopAir, you get the benefit of a first-name-basis relationship with CET, not your average distributor’s support line. Technical questions get to the right people fast, and ChopAir can escalate issues directly when a project needs it.
New Build & Retrofit
Whether you’re designing CET into a new construction spec or upgrading an existing facility’s gas detection infrastructure, ChopAir has worked through both scenarios and can advise on the practical differences in approach, timeline, and cost.
Get Started
The right CET system for your facility starts with the right conversation.
ChopAir helps you spec, source, and deliver CET gas detection systems for new builds and existing facilities across commercial and industrial HVAC environments.