Not a good choice for storing valuable specimens

Drawing up a spec sheet for scientific refrigerators and freezers can be a daunting task considering the seemingly endless array of options available.  Just keeping it cold or frozen no longer suffices.  There are numerous instances where lab refrigerator and lab freezer failures along with human error have resulted in tremendous losses in products such as irreplaceable scientific specimens and vaccines for children.

Here are suggestions that will help you reduce the risk of loss by correctly specifying laboratory refrigeration equipment.  Incidents of human error can be reduced only by establishing and adhering to a comprehensive operations manual that includes detailed standard operating procedures.

 Lab Refrigerator and Lab Freezer Cost Trade Offs

There’s no doubt that budgets are important.  Consider this:  What is the value of the contents and the loss that occurs if correct storage temperatures are not maintained?   Residential and dormitory refrigerators and freezers are not recommended for research organizations and healthcare facilities.

Lab Refrigerator and Freezer Temperature Capability

Laboratory refrigerators typically operate from 2⁰C to 10⁰C and freezers from -10⁰C to -25⁰C although there are exceptions based on models.   Low-temperature freezers again depending on models are available for temperatures to – 25⁰, -30⁰ and -40⁰C.  Ultra-low temperature freezers can be set from -50⁰ to -86⁰C.  A suggestion:  Choose a freezer that delivers the temperature you need because the lower the temperature the more power it requires.

Scientific Refrigerator and Freezer Temperature Control 

Options range from simple dial-type thermostats with letters or numbers (cold, colder, coldest) to highly sophisticated digital LED display microprocessor temperature controllers.  Top-line models such as the Nor-Lake Select series use the more precise programmable logic controls, which is the best choice to maintain the absolute minimum temperature drift.  High-end models also allow setting temperatures to one decimal place.

Laboratory Refrigerator and Freezer Temperature Sensors

These are used to collect temperature data within the unit for validation purposes.  Because temperature can vary within lab refrigerator or freezer units more than one sensor may be recommended such as two for product temperature and one for air temperature.

Lab Refrigerator and Freezer Temperature Recording

Optional temperature chart recorders collect temperature data 24/7 for storage and retrieval as needed.  In addition, a recommended practice is to manually check and record temperatures at the beginning and end of the day.

An option is an NIST traceable certified calibrated thermometer that stores and displays high and low temperatures over a period of time.

Lab Freezer and Lab Refrigerator Temperature Alarming

Alarming is an absolutely critical feature when storing valuable vaccines, pharmaceutical and biologicals.  Even the most basic lab refrigerator and lab freezer can be fitted with optional digital thermometer alarms.  These consist of an internal sensor placed in a glycerin bottle and connected by wire passing over the hinge-side door gasket or through optional sensor access ports to an outside control and display module.

The next step up is a built-in digital audio and visual high/low temperature alarm with remote alarm contacts to alert personnel elsewhere in the facility. 

The ultimate in alarming is the iLab 600 Temperature Monitoring System for local and remote alarming including contacting a list of personnel by email, text, phone or pager.  It also acquires, remotely stores and instantly retrieves lab freezer and refrigerator performance data.

 Auto Defrost or Manual Defrost Lab Freezers and Refrigerators

This topic cannot easily be summarized, so we invite you to read our post on manual vs. auto-defrost cold storage for the lab.

Combination Scientific Refrigerator/Freezer Units

If storage requirements do not warrant full-size lab freezers and fridges consider purchasing a combination unit.  High-end auto defrost units have separate doors and separate digital LED microprocessor temperature controllers, alarming systems and product temperature displays for the refrigerator and freezer compartments.   Standard models, also with separate doors, have an adjustable temperature control and optional digital thermometer alarms  

Undercounter/Countertop Laboratory Refrigerators and Freezers

Undercounter, countertop and stackable lab freezers and refrigerators are great for saving space but are more susceptible to temperature fluctuations because of their size.  These compact units are also called free standing laboratory refrigerators and freezers. 

If you are considering an undercounter unit be sure the following points are covered:

• Will the undercounter lab refrigerator or freezer fit in existing or planned casework?
• If so is there enough clearance to allow the equipment to function properly?
• Is a power outlet readily available?  Extension cords are not acceptable.

Combination undercounter lab refrigerators and lab freezers provide two storage functions in a single unit.  Some units require opening the refrigerator door to access the freezer compartment.  These units may not deliver the exacting temperature control offered by separate scientific refrigerators and freezers.  An alternative is a unit with separate doors for the two compartments.

Temperature monitoring, control and alarming systems and options are the same as found on full-size equipment depending on models selected.  Manual and auto-defrost undercounter scientific refrigerators and freezers are available.

Optional Scientific Refrigerator and Freezer Equipment

This post is concerned primarily with temperature and alarming features important to specifying laboratory refrigerators and freezers.  Other purchasing decisions include:

• Storage capacity
• Legs vs. casters
• Door locks and other security systems
• Insulated glass vs. solid doors
• Additional shelving
• Drawers or baskets vs. shelving
• Reverse door hinges
• Stainless steel interiors and/or exteriors

We hope the information here is useful when specifying scientific refrigerators and freezers.  For additional information and recommendations please contact the lab refrigerator and freezer professionals at Tovatech for expert advice on selecting the right model for your applications.

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