In food and beverage facilities, ammonia refrigeration systems deliver high cooling capacities; however, a leak can cause severe consequences for both personnel safety and product loss. The source CETCI application note describes a continuous monitoring architecture using LPT-A-NH₃ transmitters in cold storage and freezer rooms, combined with an external QCC controller located outside the entrance.
Racks, product stacks, and room height can disrupt gas movement; multiple sensors may be required.
Why Is Ammonia a Critical Gas in Cold Storage?
The reference document highlights that ammonia refrigeration is prevalent across the food and beverage industry, and a leak poses risks to worker health while causing food spoilage and economic loss. Consequently, the purpose of the system is not merely to alarm post-leak, but to provide visibility of atmospheric conditions prior to room entry and trigger required automated actions.
Mounting Location of the NH₃ Sensor
Because ammonia is lighter than air, in the source application the LPT-A-NH₃ sensor is mounted to the ceiling and positioned away from high-velocity air currents / ventilation fans. This prevents leaked gas from being driven away from the sensor by fans or compromising measurement representativeness.
How Much Area Does One Sensor Cover?
The reference document provides an example of one transmitter for approximately 5,000 ft² (approx. 465 m²). However, because racking and stored goods can create physical barriers, compartments may form that obstruct a single sensor from detecting the gas. In such cases, the manufacturer recommends multiple LPT-A-NH₃ units.
Display Operation Below -20°C
The document states that when room temperature falls below -20°C (-4°F) , an optional heater can be used for the LPT-A-NH₃, which maintains LCD screen operation at low temperatures. This detail indicates that in cold storage projects, not only sensor range but electronic and display operating limits must also be verified.
QCC and Pre-Entry Safety
The QCC is mounted outside the room and displays the readings of internal transmitters prior to entry. In the reference architecture, an integrated top strobe, manual shut-off switch, remote audible/visual alarms, and ventilation activation functions can be deployed together. If a secondary entrance exists, a QCC-RDM remote display is recommended.
Key Considerations in Project Design
| Aspect | Check |
|---|---|
| Room geometry | Whether racking/products obstruct gas dispersion |
| Sensor height | Ceiling zone for NH₃ |
| Airflow | Avoidance of direct fan exposure |
| Low temperature | Heater requirement for electronics/LCD |
| Entrances | Requirement for status indication at each entrance |
| Alarm scenario | Fan, sounder, beacon, and chiller shutdown logic |
Which Ammonia Detector Should Be Selected for Cold Storage?
The CETCI LPT series provides options configurable for diverse toxic gas sensors—including ammonia—and low-temperature applications. In cold storage, sensor quantity, low-temperature accessories, alarm sounders, remote displays, and ventilation relays must be specified in combination based on facility layout. View Ammonia Detectors.
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Frequently Asked Questions
Is an ammonia sensor mounted to the ceiling in cold storage?
In the source CETCI application, NH₃ is treated as lighter than air; the sensor is installed on the ceiling away from high-velocity air streams.
How many m² does an NH3 sensor monitor?
The source provides an example of approximately 465 m²; however, racking, pallet storage, and room geometry may increase the actual sensor count.
Does the sensor operate in a freezer room?
The temperature limits of the model must be checked. The source notes the use of an optional heater for the LCD on the LPT-A-NH₃ under conditions below -20°C.
Why must the controller be located outside the room?
In the reference architecture, the purpose is to allow personnel to verify gas levels and alarm status before entering the room.
Can ventilation be automatically activated during an ammonia leak?
The source notes that QCC relays can be programmed to trigger ventilation and alarm procedures.
What is done if there is a second door?
The source recommends a QCC-RDM remote display at the secondary entrance to view gas levels prior to entry.
Reference and Technical Note
The application architecture and model-specific technical details in this article have been compiled from an application document provided by Critical Environment Technologies Canada Inc. . As source materials may be superseded, current product codes, certificates, measuring ranges, and local regulations must be independently verified prior to project design or procurement.
Author: NOVEL Technical Team
Publication date: 7 September 2026