Ammonia Gas Detection

Ammonia gas detection is an important part of the safety standards in any industrial facility that uses Ammonia as a refrigerant. There are many factors to consider when designing a gas detection system and CTI is here to help you choose the best products for your specific scenario.


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Codes and Specifications

The International Institute of Ammonia Refrigeration (IIAR) is the authority on safety and installation standards. The gas detection specialists at CTI have studied all of the current codes and compiled them into 10-page guide, “Ammonia Gas Detection Codes and Design Specifications.”

This helpful guide can assist you in designing a system to protect your people and property from Ammonia leaks.


Ammonia Detection Guide

Where Ammonia Detectors are Required

Food Processing Facilities

Engine Rooms

Cold Storage Facilities

Blast Freezers

Fishing Vessels

Ice Rinks

Ammonia Detection in Compressor Rooms

For compressor rooms, sensor redundancy is recommended due to the catastrophic leak potential of the compressors. Audio-Visual indication inside the room, and outside of each entrance shall take place at 25 ppm NH3, emergency ventilation at 150 ppm, and compressor shutdown at less than 40,000 ppm (10,000-20,000 is industry standard) per code. To satisfy these requirements, 2 low level sensors (0-250 ppm is standard), and 1 high level sensor (0-2% is standard) are recommended for compressor rooms. The 2 low level sensors should be located on either side of the engine room, close to leak sources. The 0-2% sensor should be located centrally, accounting for the emergency ventilation path.

Ammonia Detection in Vent Lines

Vent line detectors should be located 3-5 feet above the roof line in the relief header. The GG-VL2 includes a mounting kit to attach to the pipe. A vent line release will be pure ammonia, and the sensor should be set to alarm at 5,000-10,000 ppm ammonia.

Ammonia Detection in Refrigerated Spaces

Ammonia detectors located in refrigerated spaces should alarm to a monitored location and activate audio-visual alarms at 25 ppm, in addition to closing solenoids or triggering other desired outputs. The standard range to accommodate the lower detection levels is 0-100 ppm. Sensor element ranges up to 0-300 ppm can be used for these applications as well. Sensors should be located in the breathing zone within 30 feet of a potential leak source for optimum personnel protection.

CTI Refrigeration Gas Detection

Locating Ammonia Detectors

Locate ammonia detectors within 30-45ft of a potential leak source. This leak source could be compressors, evaporators, pent houses, blast freezers and others. For rooms containing 1 sensor, locate the sensor in the breathing zone (~5ft off the floor) for optimum personnel protection. For rooms requiring multiple detectors, a 2nd detector can also be placed in the breathing zone, or placed up high with attention paid to maintenance access.

Ammonia vapor is lighter than air; however, a liquid leak will drop and accumulate near the floor, and most cold storage facilities have ventilation that mixes the air content in each room adequately for detectors being placed in the breathing zone for vapor leaks.

Choose CTI

Ammonia Gas Detectors are an integral part of a complete gas detection system.

For more information about designing a complete system see the How it Works page. To contact CTI with a quote request please use the below link, or contact CTI via phone or email.

Ammonia - What you need to know

Alarm Levels and Recommended Outputs

See below table for ammonia detection alarm levels and outputs. For a thorough guide of codes and design specifications pertaining to Ammonia, see our Ammonia Codes and Design Specifications Page.

Location Sensor Action
Compressor Room (minimum 2 sensors) GG-NH3-250 (low range detector) 25ppm – Alarm to monitored location
25 ppm – Horn Strobe outside each entrance and inside engine room
150 ppm – Emergency Ventilation
Compressor Room (minimum 1 sensor) GG-NH3-2% (high range detector) 10,000 ppm (1%) – Redundant Emergency Ventilation
20,000 ppm (2%) – De-energize pumps, compressors, and normally closed valves
Vent Line GG-VL2-NH3 1% Alarm to monitored location
Refrigerated Areas GG-NH3-100 25 ppm – Alarm to monitored location
25 ppm – Horn Strobe
35 ppm – Close liquid and hot gas solenoid valves
Enclosed Equipment GG-NH3-2% 20,000 ppm (2%) – Disable ignition sources
Machinery under 100 HP and equipment Pits (not in machine room) GG-NH3-100 25 ppm – Alarm to monitored location
25 ppm – Close liquid and hot gas solenoid valves
25 ppm – Horn Strobe inside room
25 ppm – De-energize pumps, motors, and non-emergency fans
25 ppm – Emergency Ventilation
Packaged Systems See Codes and Specifications Booklet

Ammonia is an important industrial refrigerant and is used to produce and preserve the world's food supply.

Ammonia Fact #1

CTI gas detectors are built to thrive in the harsh conditions found in food production facilities.

Ammonia is an environmentally-friendly and inexpensive alternative to synthetic refrigerants.

Ammonia Fact #2

CTI gas detection systems help make Ammonia an acceptable alternative to synthetic refrigerants.

Because of Ammonia's toxicity, it must be treated with respect and safety measures must be implemented and followed.

Ammonia Fact #3

CTI equipment detects and measures leaks so that quick action can be taken to correct problems and protect people and property.

Accurate and reliable gas detection equipment is a vital part of any Ammonia safety program.

Ammonia Fact #4

CTI gas detection systems are the industry standard for Ammonia safety. CTI detectors are built for harsh conditions and designed to prevent false alarms.

Ammonia Sensor Elements

CTI offers 2 different types of ammonia sensor elements. All CTI NH3 sensor elements are designed to be ammonia specific and eliminate false alarms from off-gassing and other environmental factors.


Electrochemical sensors for ammonia detection are ideal for most applications requiring sensitivity to levels less than 1000 ppm. They offer limited cross sensitivity issues, relatively quick response to ammonia, and good sensor life. CTI’s electrochemical ammonia sensor elements are designed to greatly reduce ill effects caused by temperature and humidity swings that cause nuisance alarms. The accuracy at lower levels makes the electrochemical sensor an outstanding choice for personnel protection throughout most facilities.

Catalytic Bead

Catalytic Bead sensors for ammonia detection are designed for high level leak detection to prevent catastrophic events. These sensors are used in engine rooms for shutdown, and vent line sensors. The catalytic bead sensor element offers quick response and accuracy at higher levels, but cannot detect reliably below 1000 ppm. Catalytic bead sensors have long life and very limited cross sensitivity issues due to the high range.

Frequently Asked Questions