Woman performing an ammonia refrigeration inspection

Ammonia Refrigeration Guidelines for Scheduled Inspections

Keeping all ammonia refrigeration units maintained and properly inspected will keep your equipment running properly and also avoid any leaks or emergency situations. 

Ammonia is highly hazardous and corrosive to skin, eyes, and lungs. Being exposed to as small a level as 300 ppm (parts per million) can cause a serious health crisis or even death. Ammonia is a flammable substance when exposed to air concentrations of 15 to 28 percent, and when mixed with lubricating oils, the range of flammability increases. In an enclosed space where there is an ignition source, or if any vessel containing anhydrous ammonia is present and exposed to fire, an explosion can occur. 

Luckily, the odour of ammonia can be recognized at 20 ppm and most people will evacuate when it is sensed. Working around ammonia requires proper training and ongoing caution. Part of maintaining a safe workplace is ensuring that the equipment is properly cared for and all possible safety hazards have been addressed.

Ammonia Refrigeration Inspection Log

Keeping an industrial refrigeration logbook is important for a number of reasons. 

  • A detailed log will help establish normal equipment operating conditions, and when inspected regularly it will allow the detection of issues to be corrected promptly. 
  • It can protect your company in the case of an accident or liability.
  • A detailed log is often required by law. The Technical Standards and Safety Authority (TSSA) requires each company to keep records of industrial refrigeration installations along with regularly scheduled maintenance. 

The beginning of each shift should include a system log entry and daily inspection of all ammonia refrigeration equipment. The System Log checklist that is provided should be followed by all operators daily. Also, each independent ammonia refrigeration unit must have a separate digital or hard-copy logbook to record observations of the normal operating conditions of the ammonia system.

Record every 4 Hours Daily:

  • The operating conditions such as pressure, temperature, and ammonia levels. This must be recorded at regular intervals and include any anomalies in performance. 
  • The results of regular ammonia refrigeration inspection tours.
  • The levels(both drained and filled) of ammonia and oil.
  • Any maintenance activities and other observations regarding equipment.

Compressors

The compressor acts as the heart of your industrial refrigeration system. It works by constantly moving the refrigerant throughout the system. When a compressor’s function is impaired(due to wear and tear or improper maintenance), it can pose serious risks and be an expensive repair. The compressor motive power should be serviced at a minimum of at least every 3 months. For reference, use this mechanical refrigeration checklist to keep on top of monthly and annual maintenance tasks.

Quarterly:

  • Inspect and securely isolate the mechanical condition of the drive. 
  • Ensure belt tension settings are correct and not over-tightened. 

Annually:

  • Inspect drive guards to ensure nothing is wearing on the belts of shafts. 
  • Check drive alignment and the condition of bolts. 

Pressure Vessels and Heat Exchangers

A visual inspection should take place weekly to ensure the ammonia refrigeration system is running properly. During this inspection, the external appearance of surface vessels, heat exchangers, and the insulation on each of these items should be noted for anything outside normal operation. Each inspection requires a report in the system log, and repairs should be scheduled whenever there is an abnormal finding.

Weekly:

  • Liquid level gauges are examined for oil buildup and drained when necessary.
  • Heat transferring liquids, such as brine and water, are checked for normal concentration levels, PH balance, contamination, and are treated when needed.
  • Oil is drained from oil drain points, preferably to a regenerator which will remove refrigerant. 
  • The system is checked for the presence of non-condensable gases.
  • Symptoms of water contamination are checked.

Air-Cooled, Finned Heat Exchangers

  • Correct air-flow direction and rotation within the unit should be confirmed every time the unit is disconnected from the power supply. All safety guards should also be inspected to maintain security. 

Weekly:

  • Inspect cooling coils and drain tubes for frost build-up. The equipment will need to be defrosted if excessive frost is found.
  • Check and adjust automatic defrost controls and operation settings as needed.
  • Check the ammonia system for the presence of non-condensable gases and purge if necessary.

Monthly:

  • Inspect finned heat exchangers for dirt build-up and contamination of tubes and fins, and clean when needed. 
  • Check heat exchangers for damage and repair as needed. 
  • Electrically test the defrost elements for proper operation and performance. 
  • Check couplings, spacers, and the belt drive (if working with direct-driven units).
  • Inspect belt tension. 

Bi-Annually:

  • Inspect fan impellers for corrosion and cracks. 

Evaporative Condensers

Weekly:

  • Clean the pan strainer, and check the bleed-off valve for normal operation. 
  • Ensure the bleed-off amount is equal to at least .03 G.P.M. per ton of refrigeration.  

Monthly:

  • Clean and flush the pan strainer. 
  • Check the operating level in the pan and adjust the float valve when required. 
  • Observe water distribution and drift eliminator for proper placement and function. 
  • Adjust belt tension as needed. 
  • Inspect fans for dirt and debris and lubricate the fan motor, pump motor, and shaft bearings according to the manufacturer’s specifications. 

In addition:

  • Inspect all guards for security.
  • Maintain correct water treatment.
  • Avoid batch chemical feeding as it is not recommended.
  • Check water for any signs of biological contamination.
  • Clean ammonia unit when needed and contact a water treatment company if water contamination is detected. 

Improve Workplace Safety with Ammonia Refrigeration System Inspections

Regular maintenance and mechanical inspections will ensure equipment remains safe and reliable and helps to minimize the risk of ammonia accidents. Keeping proper documentation of inspections and tests is a critical step in everyone’s ability to identify risks, maintain equipment function, maintain compliance with safety requirements, and schedule necessary repairs.

Adherence to an inspection and testing schedule is the best way to ensure equipment is running safely and effectively. Operators must be knowledgeable in the proper maintenance of the unit so they can identify critical points on the system that may be susceptible to corrosion, expansion and contraction, damage, leaks, or exposure to weather and the elements. Based on the results of each inspection, factors such as the identification of deficient components, the remaining life of the unit, or levels of corrosion can be determined and remedied. 

A system that is not properly inspected or maintained can equal lost revenue, increased downtime, and expensive repairs. Relying on experienced refrigeration professionals and industry-trained personnel can help identify potential risks and determine a plan of action and inspection schedule for each system. 

Maintenance services from Industrial Refrigerated Systems Ltd. will keep your cooling units in excellent working order and find potential issues before they become big problems. Our team of experienced industrial refrigeration installation technicians work to deliver maintenance that meets the needs of your company specifically.

Are you ready to schedule an ammonia refrigeration inspection? Call us today to get started.