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July 6, 2017

Stop Crying over Spilled Glycol!: The Challenges of Buffer Vials

Written by Jason Sroka

TempAlert assists companies across a wide range of domains in setting up remote environmental monitoring systems.  A common reason our customers install remote monitoring systems is to assure that their products are safe for consumers. Two major industries that use our technology are pharmaceutical applications and food services. Pharmaceuticals, such as vaccines, can lose their potency if they are not stored within a specific temperature range, which can leave patients vulnerable.Foods can spoil, raising the risk of foodborne illness. Retailers of high-risk products are often required to monitor the environments that these products are stored in and to maintain logs as evidence that their products have been stored properly.

For our pharmaceutical clients, the CDC promotes the use of physical thermal buffers to model the temperature of products, though it is not required. The thermal buffers recommended by the CDC include a wide range of materials including vials of glycol, sand, glass, or blocks of aluminum or Teflon. These buffers sit in the same environment as the product and the buffer’s temperature is monitored.  The term ‘thermal buffer’ refers to the way these materials reduce the short-term variations in air temperature that a refrigerator can experience, for example, if the door is opened and some of the cooled air escapes and is replaced with room-temperature air.  Although this might cause a brief spike in the air temperature inside the fridge, it often has minimal impact on the refrigerated products. 

Why Use a Buffer Vial?

A challenge commonly faced in monitoring product safety is that measurements are generally indirect. For example, measuring the air temperature in the environment products are stored in, as opposed to directly measuring the temperature of the product itself.  This creates challenges because a product generally changes temperature a lot slower than the environment in which it sits.  A cold drink removed from a refrigerator does not instantaneously warm up to room temperature, and similarly a product at room temperature placed into a refrigerator does not immediately reach the refrigerator’s air temperature – it takes some time for the temperature of the product and its environment to equilibrate.

Although there are many challenges, people opt to use physical thermal buffers to model the temperature of products inside refrigerators. Here are some of the challenges of using a physical buffer for your temperature monitoring: 

The Loss of Valuable Space

Buffer vials take up valuable space, reducing the amount of shelf space available to store refrigerated product. They can also impact the operational use of the refrigerator, such as getting in the way when product is put into or removed from the unit.  

Spilled Glycol

The materials stored in vials (glycol, sand, glass) can spill out of the container if knocked over, which can create a mess and compromise the contents of the fridge or freezer. The physical buffer vial substances are an added cost upon implementation, but also when replacing expired substances. Furthermore, the wide range of materials that can be used as physical buffers means that two buffers, e.g. a vial of glycol and a block of aluminum, placed in the same fridge can have different buffering characteristics and therefore generate different modeled product temperatures. 

With all of these challenges, TempAlert has come up with a solution: a virtual buffer vial (VBV). Stay tuned for our next post to find out about the virtual buffer vial and how it addresses the challenges of using physical buffers.