Who Can Calibrate Ammonia Detectors?

Whether you’re new to ammonia refrigeration or a seasoned professional, you’ve probably heard someone talk about calibrating ammonia detection equipment, a critical safety system in place to protect people, property, and the environment from an ammonia release. Calibrating ammonia detection equipment is a mechanical integrity activity that ensures the equipment is properly maintained, operated, and functioning as intended. Many facilities opt to outsource this activity to a mechanical contractor, or in some cases, bring the ammonia detection manufacturer on-site to perform the maintenance. Our team has been asked a handful of times by our clients whether this activity can be carried out by in-house personnel. It may appear that this maintenance should be performed by an external party or that a regulation requires it to be outsourced, given how often third-party contractors manage this task. Let’s break it down and talk through what’s actually required.

The International Institute of All-Natural Refrigeration (IIAR) is known as our leading best practice, or what our industry refers to as "Recognized and Generally Accepted Good Engineering Practices" (RAGAGEP). Let's look at IIAR to see what requirements are in place for ammonia detection maintenance. To determine maintenance requirements, we must refer to IIAR 6 Inspection, Testing, and Maintenance (ITM). The details provided pertain to IIAR 6-2025. Next, we proceed to Chapter 12 (Safety Systems) and locate table 12.3, which covers ammonia detection and alarm systems. The testing requirements in table 12.3 states that ammonia detectors are required to be calibrated semiannual (6 months), this 12.3 table does have an asterisk which indicates that there is more information found in the appendices of IIAR 6 which states:

• Testing of all ammonia detectors includes fixed or portable sensors (e.g., clipped and handheld)

• This table implies to all installed ammonia detectors, unrelated to the location

So far, there's been no indication from IIAR that in-house staff are prohibited from performing these maintenance tasks. Now, let's look at information from ammonia detection manufacturers like CTI and Honeywell/Manning regarding their fixed ammonia detectors. We'll also cover additional essential details that manufacturers implement for maintenance/operation tasks, which you should consider when you're in charge of these crucial responsibilities.

After reviewing the Honeywell/Manning EC-F9-NH3 manual, the maintenance/operation requirements state:

• Calibration should be performed with certified calibration gas every six months or after major exposure to a leak.

• Response test once between calibrations i.e. at three month intervals. Expose sensor to ammonia/water solution to verify proper sensor response and alarm functions.

• The response test is not required if multiple electro-chemical sensors are installed in the same room.

• Cell replacement procedure, allow cell to stabilize for five minutes and then perform the manual SensorCheck and check calibration of all new cells with certified calibration gas.

Something we often encounter is situations where in-house staff conduct the response test, as recommended by the manual to be performed every three months. This test involves using household ammonia cleaner and placing it near the ammonia detector to ensure it responds correctly. Household ammonia cleaner typically contains a 2% ammonia concentration. What is a 2% concentration? Our concentration scale is in parts per million (ppm):

• 100% = 1,000,000 ppm

• 10% = 100,000 ppm

• 1% = 10,000 ppm

The household ammonia bottle contains a 2% concentration, equating to about 20,000 ppm. During a response test, if the ammonia detector has a range of 0-100 ppm, it is highly likely that this sensitive device could be damaged. Remember, if the detector's cell is exposed to a significant leak, the manual requires recalibration or even replacement. This activity might appear counterintuitive but that's what this manufacture requires for the proper maintenance/operation. Not all manufactures have maintenance/operations tasks for performing a response test because it can easily damage the cell or cause premature failure.

Let's review the manual for maintenance/operation of the CTI GG-NH3 ammonia detectors:

• Calibrate the detector at least once every 6 months.

• Calibration should be performed with certified calibration gas.

• All tests and calibrations must be logged.

• The new cell can be span-calibrated immediately. However, an 8 hour warm-up period is required before zeroing, if necessary.

CTI does not require a response test for their ammonia detectors. However, a notable difference is that after cell replacement or power-up following installation, the detector must be powered for at least 8 hours before zeroing. This allows the ammonia detector to acclimate to the environment in which it is installed.

We used a few basic manufacturer manuals to compare the maintenance/operation requirements of each. Always refer to the manual specific to your equipment. In-house personnel can perform ammonia detection calibration but thoroughly review the manufacturer manual. One of the challenges of performing in-house calibration is maintaining a supply of certified calibration test gas, which often has a shelf life of only twelve months. Additionally, it's important to have replacement parts available for any faulty sensors or cells discovered during these tasks. The six-month calibration requirement also applies to handheld ammonia detectors, which may necessitate a variety of special adapters, tools, and spare parts for in-house maintenance. However, this is entirely feasible to accomplish if you have the personnel to support it.

Stay tuned to the MySafety blogs. Reach out to us if you have additional questions or concerns. Our team will be pleased to assist you.

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Ammonia Detection