Labmanager Logo
Gloved hand takes a sample vial out of a ULT freezer

iStock, FangXiaNuo

Purchasing the Right Refrigerator or Freezer for Your Cold Storage Needs

Explore key metrics that ensure sample integrity

| 4 min read
Share this Article
Register for free to listen to this article
Listen with Speechify
0:00
4:00

Q: What are the top considerations a customer needs to make when purchasing a laboratory refrigerator or freezer? 

A: I would say it comes down to four main considerations:

1. What will you be storing inside the refrigerator or freezer? 

2. How difficult would it be to replace these items? 

3. Under what conditions do they need to be stored? 

4. What is the longevity of the freezer or refrigerator—how long will it last in your lab?

Like with anything, you get what you pay for. We often see customers trying to cut corners by opting for lower-performance units while storing invaluable or irreplaceable samples. It's also crucial to choose equipment backed by a strong warranty from a reputable manufacturer. A solid warranty indicates that the manufacturer stands behind their product and expects it to last long-term. Basic one- or two-year warranties usually cover only manufacturing defects or initial issues, whereas longer warranties—beyond the two-year mark—are a strong sign that the company is confident in the build quality and durability of their products, ensuring their viability in the long run.

Q: What are the hidden specifications or features that are often overlooked when making a purchasing decision? 

A: There are quite a few metrics that should be considered, but overall, performance is a big one. Often, we see customers looking for the least expensive unit they can find or something that mostly meets their needs. However, performance specifications, like peak variation, door open recovery times, temperature uniformity, and stability, are critical, especially for customers in validated or regulated environments, such as clinical or pharmaceutical manufacturing. Temperature excursions beyond the operating range of two to eight degrees Celsius can create significant hassle and work for customers in regulated environments, requiring them to revalidate units, log what happened, and verify that everything in the refrigerator or freezer is still viable, whether it’s a sample or a reagent. Door open recovery time is another important metric and measures how long it takes for the internal air temperature to return to the set point after holding the door open for one minute. We use this metric as a standard benchmark when comparing our different product tiers. This approach helps customers make the right choice for their labs and specific applications.

Q: What quality standards should a customer expect from a purpose-built refrigerator or freezer in life sciences? 

A: In the past, the standard certification for lab refrigerators and freezers has been the UL 471 listing. However, starting in 2025, Underwriters Laboratories is moving toward a standard specifically designed for lab use: UL 61010-1. I would advise customers, going forward, to keep an eye on which listing their products are covered under. The new standard introduces additional performance testing to ensure that these units aren’t just converted commercial kitchen refrigerators and freezers, which have been common in the past. Eventually, everyone will have UL 61010, but at the start, you'll likely still see UL 471 across the board. Another key indicator of quality is the length of the warranty. Typically, in the life sciences industry, warranties range from one to two years for parts and labor. To sum it up, it's crucial to consider the regulatory standards—whether they're lab-specific or just general commercial-grade qualifications. The warranty length is a strong benchmark for quality, and the transparency around how performance is tested and reported is equally important.

Q: What is reserved heat capacity, and why is it important? 

A: Reserve heat capacity refers to the overhead of the compressor or refrigeration system, meaning how much additional heat can be added to the refrigerated space while still maintaining the set temperature. A classic example of this is when customers purchase a chromatography refrigerator; they typically intend to place a chromatography instrument inside and run it to keep their samples cool throughout the liquid chromatography process. However, these chromatography instruments generate heat, and compressors have a limited capacity based on factors like the amount of refrigerant in the system and the insulation of the cabinets. Several variables come into play when determining the actual reserve heat capacity of a refrigerator or freezer, but the key is that it's a measurable metric. With proper testing, manufacturers can determine the reserve heat capacity of a given refrigeration system. It's important to ensure that the equipment you place inside the refrigerator operates at or ideally below that reserve heat capacity. For instance, if you have a new refrigerator or freezer and you load it with many room-temperature samples, it may take a while to bring down the temperature. Although room-temperature samples won't continue to generate heat like active instruments, they will still impact the pull-down time due to the reserve heat capacity. 

Q: What requirements should I consider with my most precious samples? 

A:  It's going to come down to performance, once again. Samples shouldn't experience wide temperature fluctuations when you open or close the door, but sometimes customers do see variations when the door is opened—typically a temperature spike. This usually happens because an air probe is being used instead of a probe ballasted in glycerin or a solid metal slug. The critical factor here is how quickly the unit recovers once the door is opened. Are your samples sitting in warm air while the refrigeration system struggles to cool down, or does the unit recover quickly? One key performance metric is peak variation, which measures how much the temperature varies throughout a complete temperature run-time test. Typically, we run these tests for several hours, capturing a few defrost cycles. We always report our peak variation, including those defrost cycles, because that's what customer samples will experience in the field. A refrigerator will need to defrost periodically, and we want to make sure our performance claims reflect that reality. So, that's something to be mindful of. If you're considering a unit for specific uses, like blood bank storage or plasma storage in clinical settings, it's important to ensure that the refrigerator meets AABB or any other relevant standards. Another essential aspect is temperature uniformity and stability, along with the ability to validate a unit. In GMP settings, whether it’s pharmaceutical manufacturing or certain clinical applications, you'll need to perform installation qualification and operational qualification, and these qualifications are typically required regularly, along with periodic calibrations. For customers storing high-value samples, the ability to validate units is critical. Not all units in the market, particularly general-purpose or lower-performance units, will validate to a two-to-eight-degree operating range. There are additional certifications to consider, such as NSF 456 for vaccine storage and, of course, the AABB regulations for medical devices.

Related Articles

CURRENT ISSUE - November 2024

The Blueprint for Lab Safety Success

Protecting your lab's greatest asset: its people

Lab Manager November 2024 Cover Image
Lab Manager Life Science eNewsletter

Stay Connected with Life Science News

Click below to subscribe to Life Science Tools & Techniques eNewsletter!

Subscribe Today