| Written by Constance Stickler
An ever-increasing amount of goods must be transported at controlled temperatures, chilled or frozen. In addition to the usual suspects - fresh fruit and vegetables, dairy products, meat and pharmaceuticals - there are a whole host of other goods that might not immediately spring to mind.
Cosmetics and Beauty Products
Many of these products contain active ingredients and oils that degrade at too high a temperature.
Dietary Supplements
The stability of probiotics, fish oil, and some vitamin formulations depends heavily on their temperature. Probiotics, in particular, contain live bacteria that must remain viable to provide health benefits.
Biological Samples and Genetic Material
Too high a temperature can trigger or affect several things with this delicate cargo: protein denaturation and enzyme deactivation, DNA and RNA degradation, cell viability and loss of function, accelerated microbial growth and contamination, and reduced diagnostic accuracy.
High-end Electronic Components
Certain electronic components, such as semiconductor chips, circuit boards and speciality sensors, are extremely sensitive to heat and can wear out or be impaired in performance.
Specialty Beverages
High-end craft beer, fine wines and expensive spirits need the optimal temperature to prevent spoilage, flavour changes or unwanted fermentation.
Industrial Chemicals and Adhesives
Adhesives, resins and catalysts are sensitive to temperature fluctuations. For example, some adhesives are formulated to cure under certain conditions, meaning temperature spikes could activate them prematurely.
Pharmaceutical Ingredients
Active pharmaceutical ingredients (APIs), the raw components used to make medicines, are susceptible to heat, moisture and light. Particularly, those in liquid or semi-solid form can break down at the wrong temperature due to accelerated chemical reactions. In some cases, toxic byproducts can also form.
We can see that the correct temperatures determine the success or failure of the transport of many products, without which our modern world is hardly imaginable. In addition to the means required for their transport, such as suitable packaging and refrigerated containers, timely reactions to deviations from the optimal transport conditions are an essential building block for the success of the cold chain. And this is where the heroes of our story come into play: the reefer alarm.
Guardians of the Cold Chain: Introducing the Reefer Alarm
The development of refrigerated container alarms reflects the general development of innovations in cold chain logistics. Initially, temperature monitoring was a highly manual process in which container conditions were tracked with simple thermometers and monitored regularly. In some container terminals and depots, the process is still handled this way.
The biggest disadvantage, apart from the sometimes very high, dangerous and expensive workload, is that deviations are noticed but often too late. When problems occur, however, there is often only a very small window of time in which they can be corrected without affecting the cargo.
A little later in the history of refrigerated containers, simple electronic alarms appeared, but these only gave off a local signal. They were, therefore, only noticed when a person was within sight or hearing distance—an improvement on the previous state of affairs but still needing considerable improvement.
Finally, in the 1990s, a new wave of technological advances, especially in communications technology, brought about a decisive turning point. Remote monitoring systems enabled real-time temperature data and alarms to be transmitted to the staff at a central location. Instead of having to wait for the information gained from manual checks, problems could be responded to more quickly, and much cargo damage could be prevented.
Today's reefer container data acquisition systems and alarm solutions are part of sophisticated, fully automated monitoring solutions that go far beyond simple temperature monitoring. They also track humidity, CO₂, O₂, airflow, and door status. Each parameter can trigger predefined alarms when it leaves the optimal range, giving operators comprehensive insight into the reefer container's internal environment.
In addition, data can be transmitted from almost any location worldwide, even during sea transport, via satellite. And more and more transport companies and terminal operators are offering their customers the greatest possible transparency by allowing them to access the data themselves. A big step for customer trust is letting them track the transport of their valuable goods in real-time and with all incidents.
The next generation of reefer monitoring solutions will likely include extensive predictive capabilities and autonomous incident management.
For example, in the future, containers could be equipped with self-healing technologies that automatically resolve minor issues when specific alarms are triggered. Their occurrence and resolution will only be monitored and recorded remotely.
Increasingly sophisticated AI algorithms can predict alarm-triggering events even further in advance, preventing the events altogether or minimising the need for reactive maintenance.
Reefer monitoring has come a long way, from simple thermometers and hand-held logbooks to comprehensive, real-time data collection. Modern systems offer an unprecedented level of insight and control that continues to improve. These developments underscore the cold chain industry's commitment to quality and reliability.
Triggers in the Cold: Understanding Reefer Alarm Causes
The reefer alarm is more than a simple warning; it represents a complex network of data-driven insights designed to ensure the quality and safety of temperature-sensitive cargo.
Modern reefer monitoring systems are able to detect a wide range of potential problems, from temperature fluctuations and airflow blockages to power outages and unauthorised access. This enables rapid response, significantly reducing spoilage and loss.
In this chapter, we will explore the range of problems that a reefer alarm can detect:
Temperature Deviation
Overheating or Undercooling
The consequences of too high a temperature are generally well known, and we have already mentioned them above. What is not so well known is that temperatures that are too low can also have fatal consequences. Frost damage leads to unsightly goods after thawing, the quality of which suffers in more than just visual terms. In the case of live vaccines that contain living pathogens, these can die and thus become ineffective.
Set Point is Not Reached
If the set point is not reached quickly enough, this can lead to faster frosting or spoilage. If such a problem occurs, it can indicate a system malfunction, such as a faulty compressor or a refrigerant leak.
Temperature Fluctuations
Most products can tolerate some minor fluctuations in the short term, but repeated and especially more extensive changes in temperature are very damaging, for example, repeated thawing and refreezing. Temperature instability can indicate problems with airflow, sensor accuracy or cooling components.
Door Open/Close Alerts
Prolonged Door Opening
If the door is left open for a more extended period, the temperature inside the reefer rises, which often leads to condensation. Just like in the supermarket's refrigerated section or the refrigerator at home: open and close again quickly.
Unauthorised Opening of the Door
The unplanned opening of a reefer door can indicate theft or tampering. Such an alarm can automatically trigger predefined security measures, such as alerting security personnel to prevent or limit unauthorised access.
Power Outage or Electrical Problems
Power Outage
Without power, a reefer quickly loses its cooling capacity. Especially in warm climates, even short power outages can have devastating consequences when frozen goods thaw.
Low Battery Warning
If batteries power reefers, a backup solution must be found promptly when a low battery warning is issued. The battery must be serviced or replaced.
Voltage/Current Fluctuations
Fluctuations can disrupt the operation of critical components. This, in turn, can result in inefficient cooling and temperature fluctuations. Therefore, it is essential to eliminate these differences or at least keep a close eye on them.
Cooling Unit Failure
Compressor Failure
The compressor is essential to the cooling cycle. If it fails, the unit cannot cool properly.
Fan or Airflow Problems
Good airflow ensures even temperature distribution. However, if the fan fails, hot spots can develop that can dry out produce, such as leafy greens.
Refrigerant Leak
The refrigerant is essential to cooling performance; a leak can significantly reduce the system's performance.
Humidity Deviation
Many produce is sensitive to moisture: too much of it can cause it to deteriorate, while too little can make it brittle. Plants can develop mould or wilt.
Airflow Blockage
Even if the fan is running - as mentioned above - obstructed ventilation can ruin even cooling. This is the case when the vents are blocked by cargo or packaging.
CO₂ or Oxygen Levels
Certain fruits, such as apples, are transported under altered atmospheric conditions to prolong freshness by reducing oxygen and increasing carbon dioxide levels. Deviations in these levels can accelerate the ripening process, resulting in a shorter shelf life for the consumer.
Defrost Cycle Issues
If ice forms on the evaporator coil, it can reduce cooling performance. Ice also affects the proper functioning of the fans.
Communication Failures
Continuous data transmission to operators is critical for tracking and responding to changes in real-time. Only with up-to-date communication can the alerts be received and acted upon in a timely manner.
In addition to these alarms that are specific to reefers, some apply to all containers:
GPS or Location Alerts
Geofencing Alerts
Geofencing sets virtual boundaries around critical areas (e.g. ports and distribution centres). If a container leaves these areas prematurely, this can indicate an unauthorised movement and trigger security checks.
Route Deviation
In our case of refrigerated goods, route alerts are crucial, especially for cargo with strict time constraints.
Vibration or Impact
Some goods or their packaging are susceptible to vibration and impact, such as injectable drugs transported in fragile glass vials. Sudden impacts or excessive vibration during transport can cause breakage or micro-cracks, leading to contamination or spoilage.
Behind the Scenes: Alarm Automation and Predictive Maintenance in Action
In the cold chain, alarm automation and predictive maintenance have become essential pillars for protecting temperature-sensitive cargo. Traditional methods often relied on manual controls and reactive behaviour, where problems were only addressed after they had escalated.
Today, a very different approach can be taken: by leveraging real-time data and sophisticated algorithms, these systems monitor, warn and predict potential failures. This allows effective action to be taken proactively to secure cargo before or immediately after an incident occurs.
But it is not just the immediacy of these alerts that makes automation so valuable - it is the precision. Instead of overwhelming operators with frequent, general alerts, it determines exactly which problems require immediate attention. By prioritising critical alerts, automation reduces noise and highlights only the most urgent issues.
The proactive approach preserves both cargo and reefers. The historical data collected from reefer operations is analysed, and patterns are identified that may indicate an impending failure. These can include small but consistent changes in performance metrics that are invisible in daily operations. A predictive system can detect these deteriorations and signal when maintenance is needed.
These systems have many benefits for the cold chain: they enable proactive, cost-effective and sustainable reduction in operating costs and the risk of cargo loss.
The ongoing development of alarm automation and predictive maintenance is paving the way for more autonomous reefers, where systems can resolve minor issues on their own and human intervention is only required in critical situations. With the advancement of artificial intelligence and the Internet of Things (IoT), the potential for self-healing systems is emerging, where containers can make adjustments and repairs in real-time.
FAQ
What is Alarm Fatigue And What Can Be Done Against It?
Alarm fatigue occurs when a person is exposed to a high frequency of alarms, which may reduce their ability and willingness to respond effectively. The constant exposure can desensitise operators, leading to slower response times, missed alarms, or even neglect of real problems.
Not all incidents signal an emergency. Without a clear distinction between minor incidents and critical situations, all alarms appear equally urgent and important. As a result, operators may begin to dismiss events that do not require immediate action as "false alarms."
On the other hand, tiered alarms organise alerts according to urgency levels, for example, information, warnings, and alarms. A slight temperature fluctuation may trigger a low-priority warning that can be logged without immediate action. In contrast, a serious temperature increase triggers a high-priority warning with an audible alarm and immediate notification. This allows those responsible to focus on the problems that require immediate action.
In addition to the gradation in the system itself, employee training is, of course, crucial for the functioning of this approach. If the reasons for alarm fatigue and the counteracting measures are understood, their acceptance will increase. Storytelling is a good way of conveying the urgency of following instructions to the people: incidents from the past, how they came about, and the financial costs and other consequences they caused serve as demonstration material.
Takeaway
As more and more goods have to be transported under precisely controlled conditions, the importance of alarms that indicate non-compliance with them also increases. In the past, it was actually a matter of luck whether a temperature deviation was noticed in time or not.
Today, logistics teams and their customers can oversee all crucial parameters, receive alarms, and track the success of the measures taken in real time and from virtually any location. The ability to react immediately, combined with data-driven predictive maintenance that prevents many problems from occurring in the first place, is a must in today's reefer logistics, and with future technological advances, it will become even more refined and automated.
Delve deeper into one of our core topics: Refrigerated containers
Sources:
(1) P. Tang, O. A. Postolache, Y. Hao and M. Zhong, "Reefer Container Monitoring System," 2019 11th International Symposium on Advanced Topics in Electrical Engineering (ATEE), Bucharest, Romania, 2019, pp. 1-6, doi: 10.1109/ATEE.2019.8724950.
Author
Conny Stickler, Marketing Manager Logistics
Constance Stickler holds a master's degree in political science, German language and history. She spent most of her professional career as a project and marketing manager in different industries. Her passion is usability, and she's captivated by the potential of today's digital tools. They seem to unlock endless possibilities, each one more intriguing than the last. Constance writes about automation, sustainability and safety in maritime logistics.
