The Value of Alarm Door Contacts in Pharma: Freezers, Fridges, Incubators & More

Sample integrity is essential to run a profitable company. A simple yet critical component to protect your lab against catastrophes and improve your scientific reproducibility is to implement door contact alarms on refrigerators, freezers, incubators, and controlled environments. 

Door contact alarms are magnets that notify you if a door is open or closed. They provide real-time information about the status of entrances or access points. They are cost-effective and easy to install, making them an excellent option to ensure comprehensive oversight of all units.

Why labs need door contact alarms

  • Protect assets
  • Reduce human error
  • Improve operational efficiency
  • Create actionable SOPs
  • Provide early warning capabilities
  • Maintain unit environments

What triggers a door contact alarm?

1. Door Openings

Depending on the unit’s make and model, there might be varying behaviors regarding door openings, recovery times, and the time it takes to trigger an alarm. Probes are placed near the front of most units and can be susceptible to temperature fluctuations when the door is opened and room-temperature air enters the unit. This can create nuisance alarms.


  • Overlay door openings with temperature data to set actionable SOPs and ensure consistent storage conditions. 
  • Environmental monitoring provides accurate insights into unit behavior, including recovery time between door openings. 
  • Perform recovery tests to understand unit performance. Tests should be performed periodically as units age and take longer to recover. Presenting this data to management will help justify capital for equipment purchases.

graph showing door openings in laboratory

2. Ice Build-Up

Ice build-up occurs when humidity in the air comes into contact with the freezer temperature when the door is open. It’s a slow and gradual process, but it can become too much for the magnetic seal to hold and cause the freezer door to pop open. If a unit is covered in ice, the build-up can provide false temperature readings and create a false sense of security that everything is running smoothly. In the case of a -80ºC freezer door left open, if you don’t have a door contact and only rely on temperature alarms, it will take around 5-7 hours for the alarm to be triggered.


  • Prepare your lab personnel for a freezer failure in the lab.
  • Check for any signs of ice accumulation within the freezer compartments. 
  • Ensure nothing is going through the door seal.


Why are alarm door contacts important for incubators?

They help maintain the optimal environment within incubators. When a door is left open, it leads to the escape of heat and CO2, and the intrusion of external CO2 at a different temperature. This can delay the unit’s internal recovery, especially if it’s an older model.

Without door contact alarms, a sudden temperature drop inside an incubator might mislead users to think the unit was left open. Having door contact alarms makes it easier for lab users to perform root cause analysis.

Can I use door contact alarms on older units?

Door contact alarms provide a lifeline for older equipment. Installing door contact alarms offers visibility and early warning capabilities to determine the root cause of a unit’s behavior. This empowers labs to prepare for potential disasters.


Using door contact alarms and 24/7 Monitoring-as-a-Service is indispensable for preserving sample integrity, ensuring regulatory compliance, and safeguarding valuable assets in laboratory environments. To find out how XiltriX can help you keep a pulse on your lab, give us a call at 858 208 0368.