ULTRA-LOW TEMPERATURE FREEZERS
KEY CONSIDERATIONS FOR COVID-19 VACCINES:

SUPPLEMENTCONTRIBUTORS:• Dan R. Catchpoole, President, ISBER.; Biospecimen Research Services, CCRU, Kids Research, Sydney Children’s Hospital Network, Westmead,
Australia. Daniel.catchpoole@health.nsw.gov.au

•
•
•
•
•
•
•
•
•
•
•
•
•
•

Piper Mullins, President Elect, ISBER; Smithsonian Institution, Washington, DC, USA. MullinsP@si.edu
Jim Vaught, Editor-in-Chief, Biopreservation & Biobanking, USA. jvaught44@gmail.com
Cheryl Michels, Freezerworks, USA. cheryl@dwdev.com
Monique Albert, Secretary, ISBER; Ontario Tumour Bank, Ontario Institute for Cancer Research, Canada. Monique.Albert@oicr.on.ca
Alison Parry Jones, Director-at-Large for Europe, the Middle East and Africa, ISBER; Wales Cancer Bank, Wales. Parry-JonesA@cardiff.ac.uk
Daniel Simeon Dubach, Chair, Standards Committee ISBER; Medservice, Switzerland. daniel.simeon-dubach@medservice.ch
Molly Ferrara, Hamilton Storage Technologies Inc, USA. mferrara@hamilton-storage.com
Ian Pope, IC Biomedical, USA. ipope@icbiomedical.com
Tim Root, Stirling Ultracold, USA. troot@stirlingultracold.com
Mark Sawicki, Cryoport Systems, USA. msawicki@cryoport.com
Pasquale De Blasio, Integrated Systems Engineering, Italy. pasquale.deblasio@isenet.it
Andy Pazahanick, Select Gases, USA. apazahanick@selectgases.com
Tracy Fogle, Diversified Laboratory Repair, Inc. USA. tfogle@dlrepair.com
Buzz Bies, MVE Biological Solutions, USA. Buzz.bies@MVEbio.com

Many cold chain issues occur in the “last mile/kilometre” of vaccine distribution, with samples lost due to improperly
handled freezers. ISBER, the International Society for Biological and Environmental Repositories, offers our shared expertisein cold chain management to educate new users of ultralow temperature (ULT) -70°C freezers as part of COVID-19 vaccine
distribution programs.

For more information on the Best Practices referenced here visit(or scan QR Code): isber.org/page/BPR

PURPOSEThis document is intended to provide guidance managing the deployment of frozen COVID-19 vaccines. It is not designed to be
a comprehensive series of instructions on cold chain management. Rather this is designed to be a guide to the considerations
that need to be addressed by managers wishing to set up a robust system for the SARS-CoV-2 vaccine deployment.

ULTRA-LOW TEMPERATURE FREEZERS:
KEY CONSIDERATIONS FOR COVID-19 VACCINES SUPPLEMENTBACKGROUND
With the urgent global need for SARS-CoV-2 vaccines,
pharmaceutical manufacturers, third-party logistics providers
and healthcare systems are addressing significant challenges
that threaten widespread vaccine distribution and availability.
Whilst the vaccine developers and public health authorities
are seeking the rapid deployment of as many doses throughout a population as possible, the logistics of distribution are,in many cases, not well defined, nor do they appear to be arequirement for vaccine use approval.1
The UK’s NHS (National Health Service) SOP for COVID19
vaccine deployment in community settings, dated December
18 2020 (p7, 38, 39) states;“Vaccines must be transported only in approved andvalidated cool boxes, and the temperature of the coolbox and contents must be monitored and reviewed
before use. Means of detecting when a temperature
excursion has occurred are required and that any‘out of specification’ recordings are addressed
promptly and appropriately, and that a full audit trail
is maintained.”

The following documents detail examples of cold chain
actions from the point of receipt of vaccines at the deployment centers.
• The NHS Specialist Pharmacy Services exemplar document for vaccine cold chain management. 2• Delivering Pandemic Resilience: How to secure stablesupply chains for vaccines and medical goods during the
COVID-19 crisis and future health emergencies3
According to the World Health Organization, more than
50% of vaccines may be wasted every year because of2

temperature control, logistics and shipment-related issues.
Loss of cold chain security through mismanagement offreezers leading to breaks in the cold chain create shortterm chaos 4 reduction in clinical efficacy and public healthbenefit as well as long term financial losses 5. ULT cold chain
logistics requirements cause considerable issues for healthauthorities to negotiate, especially the use of ULT freezers.
These issues may be even greater for the local family doctor
or remote clinic outpost.
Distribution of vaccines in the current situation requires a different viewpoint from the normal (prior) considerations when
examining ideal storage modality. Under normal circumstances we consider temperature requirements, availabilityof refrigerant or power for refrigeration, long term storage
capacity requirements, transaction types and quality criteria.
In a simple single delivery with a well defined cold chain,many of these requirements are less significant. The extent
of the current global deployment required has placed additional consideration of cold chain logistics that are only now
becoming apparent. The necessary requirements at multiple
smaller and often remote locations that must be deployable
rapidly must occur without the need for complex installationof special freezer storage or local infrastructure.
With the leading SARS-CoV-2 vaccines requiring storagein -80°C and -20°C temperature conditions, “last mile”6
vaccine distribution gets even more daunting as regional/
local levels of government, healthcare and pharmacy
systems are responsible for planning. The ability to replenish
refrigerants like dry ice and liquid nitrogen during vaccine
transport by courier or a transport company in an efficientmanner may not be feasible in local and remote settings,
becoming a rate-limiting step in the successful deploymentof the vaccine, especially as supply and demand needs
increase over time. Those that warehouse the vaccines
will need to either maintain multiple models of freezers toaccommodate the current and potential future vaccine
requirements or find a solution that will provide safe storage1

https://www1.racgp.org.au/newsgp/clinical/tip-of-the-cold-chain-iceberg-vaccines-worth-26-mi2https://www.sps.nhs.uk/home/covid-19-vaccines/pfizer-biontech-vaccine/pfizer-biontech-handling-in-trusts

3

https://www.dhl.com/au-en/home/insights-and-innovation/thought-leadership/white-papers/delivering-pandemic-resilience.html

4https://www.cnn.com/2021/01/06/us/california-broken-freezer-vaccines-trnd/index.html

5https://www.abc.net.au/news/health/2020-12-04/uk-coronavirus-rollout:-what-does-it-mean-for-australia/12946414

6“Last mile” is a general term used within the cold chain space to indicate the connection from a regional repository to the end patient recipient.

ULTRA-LOW TEMPERATURE FREEZERS:
KEY CONSIDERATIONS FOR COVID-19 VACCINES SUPPLEMENT

for a large range of temperature requirements. Meanwhile
the demand for stand-alone ULT freezers has significantly
increased lead times from an average 4 weeks to as longat 16-18 weeks, which creates issues for many local areas ingaining the necessary equipment to do the job. The ideal
solution for storing vaccines at the local areas may not be
available because of long lead times.
Consistency in storage is key. One of the key drivers associated with ULT freezer logistics and distribution will be related to
the recently released ISO-21973 (Biotechnology — General
requirements for transportation of cells for therapeutic use).
It includes recommendations around management of equipment being utilized for the SARS-CoV-2 vaccine distribution.
Vaccine preparedness teams across the globe are now finding
themselves urgently planning the provision of ULT equipment
and dry ice services, sometimes with limited experience andguidance to support their efforts.
The International Society for Biological andEnvironmental Repositories (ISBER), represents professional experts in the distribution of biological material. ISBER
is dedicated to the creation and promulgation of international
best practices and standards in biobanking, including establishing cold chain security for biospecimens and therapeutics.
This document just released draws on accepted practices
known to ensure robust ULT product storage and distributionthat are routinely used by biorepositories. The document
represents a consensus view from the biobanking community. The organization drew on the expertise of biorepository
managers and industry vendors to draft a position statement
intends to supplement guidance from national and local
health agencies on managing the cold chain deployment offrozen COVID-19 vaccines.
The Best Practices below are only selected examples relevantto the consideration being described. At no point is this considered a comprehensive list but merely an extraction from ourmore thorough ISBER Best Practices: Recommendation
for Repositories 4th Edition which should be considered
the source material 7.

7

https://www.isber.org/page/BPR

8

https://www.cdc.gov/vaccines/hcp/admin/storage/toolkit/index.html

STAFF TRAINING IS CRITICAL

p Provide all vaccination staff with proper training
in cold chain supply, freezer operations and frozen
sample handling.
According to the CDC’s Vaccine Storage and Handling
Toolkit8;“Vaccine storage and handling practices are only aseffective as the staff that implements them. Staff thatis well-trained in general storage and handling principles and organization-specific storage and handlingstandard operating procedures (SOPs) is critical toensuring vaccine supply potency and patient safety.”

It needs to be recognized that large hubs will have morecapable and trained staff. Yet, the further from resourceful
hubs, into regional, local and even more remote areas,
it will be less likely that administrators will have access totrained, experienced specialists who understand cold chain
management. Furthermore, knowledge of the sciencebehind vaccine storage requirements (i.e., cryobiology) will
strengthen practices at all levels. Hence, consistent messaging through education and training must be made available.
The most effective manner for this may be through online
education and on demand webinars. ISBER, as experts incold chain logistics for biospecimens and therapeutics has
such educational resources available.

3

ULTRA-LOW TEMPERATURE FREEZERS:
KEY CONSIDERATIONS FOR COVID-19 VACCINES SUPPLEMENTISBER Best Practices: C12.3
Equipment Maintenance and Repair; G. Training
Properly trained personnel with expertise in monitoring and repairing repository equipment (especiallyfreezers and refrigerators) should be used for regularand emergency repairs.
These trained technicians may be on the repository
staff, may be on staff within the larger organization
within the institution in which the repository resides,
may be available through a “fee for service”
arrangement with a commercial entity with thisexpertise, or repair services may be obtained from asimilar entity on a retainer basis.
Training Resources available at:
isber.org/page/webinars-on-demand

ULT FREEZER SELECTION MUSTMEET LOCAL REQUIREMENTS

p DO NOT use frost-free freezers as they use awarming cycle and lead to regular temperature
excursions.
When selecting an ultra-low temperature (ULT) storage
system, it’s important to consider the following:
Temperature Settings: Most mechanical cold chain
equipment can handle one temperature only. Is theinternal storage temperature flexible? Hold time at designated temperature especially during peak times when
open and closure may be more frequent.
Freezer Size: What is the system’s capacity andthroughput? Is the system modular? Can it be expanded
if necessary? What is the system footprint considering
peripherals? For this vaccine deployment health care4

facilities and pharmacies are choosing to choose non-traditional ULT freezer appliances with highly compact
designs for remote, portable and even mobile use.
Larger freezer units take longer to recover temperature
after door openings.
Portability: Can it be repurposed after the vaccination
program is complete. Can the system be easily relocated? Is it mobile?
Suppliers and Support: Is the system/supplier/service
provider dependable? What is the currency, frequency ofdelivery and installation time? Can regular maintenancebe easily performed in order to maintain the system’s
peak performance? What happens if there is a problem
with the system? How easy is the system of use and does
it require minimal staff training.
Monitoring: Are 24/7 monitoring and alarm systems
available? Will trained personnel be available to respondat all times? Can the monitoring system be tamperedwith? How simple is it to create a audit trail of freezer
stocks (e.g. biospecimens, vaccine doses)? Are service
agreements availability for both freezer and monitoring
system and do they provide immediate coverage.
p Choose freezers with the widest temperature
range to accommodate multiple vaccine
candidates and choose the smallest freezer
required.
Consider preparing for the range of temperatures at which
multiple COVID-19 vaccine candidates must be stored. Not
being able to meet the storage requirements of any oneof the approved vaccines will limit vaccine administration
options at the point of patient care, especially considering
multi-dose patient requirements. Aim to cover all the options
by choosing ULT freezers with the widest temperature setpoint range to optimize ultra cold storage for all vaccine
candidates.
Freezer should be capable of storing multiple types of
packaging formats. Note that whilst typical reference size forstorage boxes are 10X10 cryoboxes, the Pfizer vaccines come

ULTRA-LOW TEMPERATURE FREEZERS:
KEY CONSIDERATIONS FOR COVID-19 VACCINES SUPPLEMENTin “pizza boxes” which is preferred but will limit the cold chain
equipment. Minimum freezer opening (neck size) is estimatedas 24” for storage of these large delivery boxes which is estimated to comfortably store 5-7 of the Pfizer shipment boxes.
p Confirm the power configuration available in yourlab prior to purchase, especially in areas with
low-grade power supply.
What are the voltage (e.g., 120v or 220/208v) and amperage(e.g., 10, 15, 20amps) requirements? ULT freezers typicallyplug into high-voltage power outlets with multiple power
supply requirements when deploying units in various regionsof the world. Organizations can avoid building power modification delays and careful planning of ULT freezer power
options to meet regional standards, by installing ULTs with awide voltage range and universal power built in.
To address environmental concerns, energy-star rated
ULT freezers are available and recommended. ULT freezers
utilizing natural, eco-friendly refrigerants are available andrecommended.
p Have a dedicated backup power system in place incase of power outage.
Ensure ULT freezer outlets are on an emergency circuit
powered by a generator preferably with an uninterrupted
power supply (UPS) to provide short term power during thepower correction that would occur in the event of a powerinterruption. Emergency backup systems that automatically cool their contents with LN2 or liquid CO2 should beconsidered.
p Install an independent internal thermometer
sensor to log/alert against temperaturefluctuations. Ensure internet or Wi-Fi access andsend alerts to multiple staff.
Temperature monitoring and data logging must be recordable and/or transmittable quality so as to be able to regularly
report data to ensure compliance with required conditions
and thus efficacy of vaccine.
It is strongly recommended to install an independent alarm

monitoring system on any ULT unit. This is additional to thefreezer’s original system and acts as an independent monitoring system that can be programmed to alert staff with enoughtime to resolve the problem and protect the integrity of thestored product. The optimal number, type and location oftemperature probes used for freezer monitoring should beconsidered and should come with a Certificate of Calibration.

ISBER Best Practices: C.1 Storage and Processing
Equipment; C.3. Mechanical Freezers;
B.5. Backup Power
Temperature mapping should be performed to
document and control the temperature distribution
within a storage area upon installation and periodically at defined intervals.
Adequate airflow around freezers and refrigerators
will decrease the risk of overheating of compressors,
shortening compressor life, and decrease growthof mold and other harmful microbial contamination
situations.
Heating, Ventilation, Air Conditioning (HVAC)
systems are more efficient than simple ventilation
systems at maintaining temperatures and humidity.
Repositories should be aware of the location of theirbuilding generators and confirm that they are on the
backup system. Repositories should be aware of thelocation of their building generators and confirm thatthey are on the backup system.

ULT FREEZER INSTALLATIONREQUIRES A SPECIFIC STORAGE
AREA
Be aware of facility infrastructure obstacles such as floor
space constraints, high energy draws, power distribution,and limited Heating Ventilation and Air Conditioning (HVAC)

5

ULTRA-LOW TEMPERATURE FREEZERS:
KEY CONSIDERATIONS FOR COVID-19 VACCINES SUPPLEMENT

capacity when quickly ramping up ultra-low freezer capacity.
This can be mitigated by selecting ULT models with higher
storage density that require less space, energy and infrastructure to operate over a wider range of ambient conditions andvoltages.
p Each freezer requires an independent circuit.
Ensure outlets are on an emergency circuit withbuilt-in redundancy.
If two units are plugged into the same outlet it is likely you
could trip the breaker and impact both units. While not an
issue in many regions, local facilities within rural and developing economies may contend with low-grade power. In this
scenario, special power conditioners may be required for ULT
operation.
p Ensure room where freezer will be housed canhandle additional heat load. ULT units will increase
humidity and temperature.
All ULT units, even the more energy efficient units, have significant heat rejection. Many ULT models produce excessive heatas a by-product of ULT production. The more ULTs running ina facility, such as a biobank in a central warehouse, the moreheat that builds up within the building interior. These risingambient temperatures can have significant impact on ULT
performance, reliability and efficiency. This may cause HVAC
systems to work harder, especially in warmer climates andseasons, leading to increased strain on building systems,
higher energy costs and can even lead to freezer failures. If
the HVAC of the room was already at capacity, adding a new
ULT unit may overload the system. ULT freezers need to have a
low ambient environment, preferably around 22oC. A warmer
room will negatively affect the recovery rate of the unit andpotentially cause restriction or oil logging issues.
p ULT freezers need to pull air in and exhaust without
restriction. Check clearance requirements outlined
by each manufacturer before purchase.
Confirm the placement of the unit meets the clearance requirements outlined by each manufacturer in the operator’s
manual. This is especially important on the front and back6of units. ULT freezers need to pull air in and exhaust without
restriction. A ULT freezer placed directly against a wall cannot
exhaust and will recirculate on itself and cause the unit tooverheat. Care should be taken to ensure the ULT freezer is
not placed directly under an HVAC supply register as it would
blow air into the unit during door openings. Do not place theunit in direct sunlight, especially afternoon sun.

ISBER Best Practices B. Facilities
An efficient repository has many particular locationand design elements to ensure the safe-keeping of
the material stored, support the equipment employed, and provide a safe and effective working
environment for the repository staff.
In planning the design of a repository, it is necessary to know the types of material being stored,
the required storage and handling conditions, theprojected retention periods, projected growth of
the specimen numbers, and the projected use of thematerials.
The design should include sufficient space to accommodate the material planned for initial, future,and backup storage and also provide for the safe
movement of people, equipment, and specimens, as
needed, or as required by law and/or other regulatory agencies.

ULT FREEZER OPERATION
AND MAINTENANCE MUST BE
COORDINATED

p Access to vaccines needs a strict procedure for how
staff will manage door openings. Aim for few andshort door openings to avoid freezer temperaturefluctuations. Allow the freezer to return to set
temperature.

ULTRA-LOW TEMPERATURE FREEZERS:
KEY CONSIDERATIONS FOR COVID-19 VACCINES SUPPLEMENT

Limit door openings and minimize the length of time foreach opening. ULT units are not designed for continuous
door openings and need time to recover after each opening.
Utilize the interior doors/sub doors for the ULT freezer. This
will allow for greater temperature control for the products
stored behind the closed inner doors. The use of small portable ultra low temperature containers for transient storage ofvaccine doses may also need to be considered in the daily
work flow.
When loading a ULT unit it is recommended by most manufactures to load one shelf at a time. Load the top shelf thenclose the door and allow the temperature to recover. Thencontinue with the subsequent shelves.
p Avoid an empty unit. If you do not have productto fill the unit, consider adding empty aluminumracks to fill it.
Create a digitized audit trail of content entry and withdrawal.
p Regularly clean the condenser and gaskets toprevent ice formation, especially around doors.
The condenser is how the unit removes the heat from thecabinet. If condenser is dirty or blocked it can cause the refrigeration to run warm and cause a restriction or oil logging
and shorten the life of the compressor.
Given the extreme temperature of ULT freezers they often
form ice on the gasket and around doors. If not regularly
cleared it can prohibit the door from closing properly andallow outside air to infiltrate into the cabinet. Ice can also
lead to damage to the door latch and door alignment. It is
inevitable that the walls inside of a ULT freezer will accumulate ice/frost over time. Some manufacturers recommend
defrosting a ULT freezer yearly, although this is not always
feasible in most applications. However, if a unit has excessive ice buildup on the interior walls beyond ½” it will
directly affect temperature uniformity throughout the unit. In
some cases, this can create a 10oC difference between the
top and the bottom of the ULT freezer.

p Ensure ULT freezers are calibrated for accuracy oftemperature display.
It is not uncommon for the temperature sensor and electronics to drift over time.
ULT units are designed to maintain temperature. They are notintended to cool material down to -80oC. It is preferable thatmaterial placed inside a ULT unit is already at -80oC.
To ensure accurate temperature monitoring, test audible andvisual alarm functionality regularly. Alarm battery should bechecked regularly and replaced approximately every 2 years.
Compressor amp draw should be checked during each preventive maintenance inspection. The amp draw can provide
insight as to how hard a compressor is working and can
indicate the potential for unit failure.

ISBER Best Practices: C.12 Equipment
MaintenanceA system for preventative maintenance and repair ofstorage equipment, supporting systems, and facilities should be in place. System maintenance shouldbe performed at regular, established intervals per
manufacturer’s recommendation and as determined as fit for purpose aligned with the repository’s
practices.
Freezer and refrigerator units should be qualified
prior to and periodically during use by performing
temperature mapping with multiple thermocouples
placed throughout the storage unit to evaluate consistency of temperature.
This temperature profile should be performed prior
to its initial use so that warm and cold spots that
could be problematic for material storage can be
identified.

7

ULTRA-LOW TEMPERATURE FREEZERS:
KEY CONSIDERATIONS FOR COVID-19 VACCINES SUPPLEMENTULT FREEZER EMERGENCY
PLANNING

p Draft an emergency plan in case of freezer failure,
power outage, natural disaster, and other common
hazards.
Emergencies can cover a wide range of natural and man-madedisasters, all of which may have varying effects on the facility
and on the ability of the repository to carry out its essentialfunctions. The type and duration of disasters may depend on
the geographic location at which the repository is located.
Emergency plans should consider scenarios including alternative storage facilities if the primary freezer fails, building
access for out-of-hours emergencies, packing of vaccine for
rapid transfer to new storage unit and how a freezer temperature will be monitored during a power outage.
p Have a written procedure for transferring
specimens to alternative storage (e.g. dry ice).
We see the lack of preventative maintenance programs for
ULT’s and LN2 cold chain equipment as the primary reason for
issues/failures. Ensure there is available space for alternative
storage. This includes dedicated empty freezer space maintained at operating temperature.

ISBER Best Practices: B.8 Emergency
Preparedness
Repositories should have a written procedure fortransferring specimens from a failed or malfunctioning unit (one that has exceeded or is on the vergeof exceeding its acceptable operating temperature
range or become over-filled) and for the return of thespecimens to their original location once it is considered safe to do so.

8

The procedure should include the freezer or refrigerator name or number as well as the location
within the freezer where the specimens have been
relocated. Repositories should have backup power
and/or alternate cooling systems in place, as well as
an emergency response plan.
Systems should be equipped with redundant compressors that operate under an electrical alternating
control system.
To prepare for the possibility of freezer contaminationby blood or other fluids, decontamination equipment
and procedures should be available in advance.

SHIPPING & LOGISTICS: DRY ICE
AND LIQUID NITROGEN (LN2)LOGISTICS
Regional/local leaders are being challenged to get vaccinesfrom central repositories to remote or immobile communities
like extended care facilities, nursing homes, and rural populations, without breaking the ULT cold chain. This is wheretraditional ULT freezers are too bulky, heavy and generally
impractical.
While the use of dry ice cooling may be considered by someto be an option here, it continues to be in short supply and requires PPE and training for safe handling. Also, an average dry
ice block has a life span of only 18-24 hours. Especially considering multi-week, multi-dose inoculation requirements, dry
ice cannot provide long-term, reliable protection of vaccine
dose efficacy.
With the limited availability, life span and temperature controlof dry ice cooling methods, best practices for rapid andremote deployment of ULT storage will become increasingly
critical for regional/local delivery of safe and effective COVID19 vaccines to the public.

ULTRA-LOW TEMPERATURE FREEZERS:
KEY CONSIDERATIONS FOR COVID-19 VACCINES SUPPLEMENT

p Purposep Monitoring

Dry ice can be used to keep the vaccines cold longer. Dry ice
can have longer hold times if it is saturated in LN2, done in vapor
phase not liquid phase. For expeditious execution of a vaccine
program, even large facilities could utilize small liquid nitrogen
dewars that could be easily delivered by gas suppliers.

Temperature monitoring: all COVID-19 vaccine storage anddistribution require temperature monitoring with digital dataloggers to verify cold chain trail.

p Supply
Dry ice availability at the Hub site, but also at the delivery site,
is very important. Many observers predict a shortage of dry ice
world-wide, which is needed to fill/refill the shipping boxes.
Fast Couriers like UPS decided to produce dry ice internallyand plan to send 42-pounds of dry ice to vaccination points
with the shipment of vaccine doses. Experts predict that at
vaccinations’ peak, the need for dry ice could be 60,000
pounds (27.000 Kg) to 70,000 pounds (32.000 Kg) per day.
However, many local areas do not have dry ice readily available. Also the periodic shortages of CO2/dry ice in partsof the world can be an issue. Most locals will need to be
instructed on safe handling and using of dry ice.
p Handling and Safety
Train all staff on safe handling, use, and disposal of dry ice.
LN2 freezers, shippers, dewars and laboratory units can beused for storage/distribution of vaccines. It should be donein vapor phase vs liquid.
Shippers with dry ice need to be kept in well ventilated area,with recommended O2 monitor within the rooms where dry
ice is used to protect workers.

p Shipping Equipment
From a shipping standpoint, double-walled vacuum-insulated containers would have the best possible thermal
insulating properties. These units whether typically used at
this temperature or at colder temperatures would provide
superior hold times compared to other technologies.
The lower transmissivity of heat would translate to a lower
sublimation rate for dry ice. So, a large aluminum dewar oran ISO framed freezer designed for shipping could holddry ice for longer durations than other currently proposedsystems. This would also allow in-situ storage and reduce dry
ice refill requirements easing the administrative burden on
vaccine administering facilities. In less developed countries
and more remote locations, this could become an importantconsideration.

ISBER Best Practices: J5. Cold Chain
The management of cold chain should include allmeasurements, qualifications, validation, and corresponding documentation. All components andoperations should be demonstrated to performreliably.
p Equipment Redundancy and Wastage.

ISBER Best Practices: F6.7 Dry Ice Safety

Start-ups and small labs are often interested in refurbishedunits to control their costs.

Adequate signage should be used for appropriate
storage.

Dry ice units and containers requiring disposal will need to bediscarded in an environmentally conscious way.

Oxygen monitors/alarms should be used whenliquid nitrogen, liquid CO2, and/or any other oxygen-depriving compressed gases are used.

9