Plan Your Cryogenic Storage Facility With Confidence
How To Guide
Published: December 5, 2024
Credit: Azenta
Cryopreservation is essential for maintaining the viability of cells and tissues over time. However, improper storage or handling conditions can compromise biological samples and impact research outcomes.
When building a new cryogenic storage facility or upgrading an existing one, it’s vital to consider how to make it safe, efficient and reliable.
This guide explores recommendations from the International Society for Biological and Environmental Repositories (ISBER) and offers the guidance needed to successfully run a cryogenic storage facility.
Download this guide to explore:
- Key considerations for designing and equipping a liquid nitrogen (LN2) storage facility
- Best practices for installing and maintaining LN2 systems
- Safety measures and emergency preparedness plans for LN2 facilities
A Practical Guide
to Planning
a Cryogenic
Storage Facility
GUIDE
azenta.com 2
Contents
Introduction 3
Designing and Equipping Your LN2 Facility 4
Facility Considerations for LN2 Storage � � � � � � � � 4
LN2 Storage Equipment Types � � � � � � � � � � � � � � � � 6
LN2 Supply Systems � � � � � � � � � � � � � � � � � � � � � � � � � 7
Monitoring Your LN2 Facility and Storage Units 8
Installing and Maintaining LN2 Equipment 11
Installation and Setup � � � � � � � � � � � � � � � � � � � � � � � 11
Electrical Power � � � � � � � � � � � � � � � � � � � � � � � � � � � � 12
Calibration � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 13
Verification � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 13
Routine Maintenance � � � � � � � � � � � � � � � � � � � � � � � 14
Ensuring Safety in Your LN2 Facility 16
Oxygen Sensors � � � � � � � � � � � � � � � � � � � � � � � � � � � � 16
Personal Protective Equipment (PPE) � � � � � � � � � � 17
Training Ensures Safety and Specimen Quality � 18
Preparing Your LN2 Facility for an Emergency 19
On Call Staff � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 19
Backup Capacity � � � � � � � � � � � � � � � � � � � � � � � � � � � 20
Other Best Practices for Risk Mitigation � � � � � � � 20
Conclusion 22
Streamline your Cryogenic Storage with Azenta Life
Sciences � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 23
Azenta Life Sciences azenta.com 3
Storing biological materials, especially living cells and tissues, can be a complicated process Improper handling or
storage conditions can damage cells, reducing viability and compromising their utility in downstream applications
Keeping specimens below -135°C, the glass transition temperature (Tg) of water stops all metabolic activity and safely
preserve cells indefinitely This process, known as cryopreservation, is key to maintaining the integrity of sensitive
biological materials for extended periods of time With a boiling point of -196°C, liquid nitrogen (LN2) is the gold standard
for cryopreservation1
Specimens can be stored in either the liquid or vapor phase of LN2 to keep them below Tg LN2-
based storage units operate very differently than conventional freezers, requiring specific guidelines to be followed
when housing them in a storage facility In this new guide, Azenta has brought together the most critical considerations
following the best practices of The International Society for Biological and Environmental Repositories (ISBER)2
These documents provide comprehensive recommendations for setting up and maintaining an LN2 storage facility,
including good design and robust operational procedures to reliably protect the integrity of cryogenic materials as well
as the safety of users
Introduction
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LN2 is the ideal preservation medium for biological material
because it can be stored indefinitely without loss of quality
and doesn’t rely heavily on mechanical freezers, which can
be unreliable To set your facility up for success, there are
several key considerations for selecting the appropriate space
and equipment
Facility Considerations for
LN2 Storage
The design and construction of a repository is critical—from
ensuring security of stored material to developing a safe
and optimal working environment for staff As a result, it is
necessary to consider the following:
Designing and
Equipping Your
LN2 Facility
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Space: You need to provide enough space for your cryogenic equipment with adequate
room for operations, verifications, maintenance, and cleaning The width and height
of doorways, hallways, elevators, storage space, and outdoor areas should also be
considered to ensure there is room for installation and relocation of this equipment
Air Flow, Circulation, Temperature, and Humidity: Ensuring sufficient air circulation
is necessary to prevent excess moisture and condensation Excess humidity can lead
to fungal growth, impacting specimen integrity and causing health problems for your
staff Air circulation should be managed so that the air passing over the opening of a
storage unit is minimized, as this can accelerate nitrogen boil off Adequate ventilation
and monitoring are also critical to ensure proper oxygen levels are maintained
Network Reception: Cellular and/or wireless reception can be considered but using
wired connections are recommended, as they can ensure a reliable network connection
Electrical Power: While LN2-based storage units do not rely on electrical power for
active cooling, electricity is needed for monitors, alarms, and replenishment of LN2
for auto-fill systems Having a backup power system to provide monitoring and alarm
capabilities if a facility is unattended is recommended Your battery backup should be
capable of providing one complete filling cycle
Flooring and Structural Support: Flooring should be easy to clean The weight and
vibration of large cryogenic units is also important to evaluate, as over time this will
cause wear on floors In addition, the weight of such equipment must be taken into
consideration when relocating or designing a new facility
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LN2 Storage Equipment Types
LN2-based storage units are categorized into two groups: small aluminum Dewars and large
stainless steel or plastic storage units Both are designed to hold LN2 efficiently either in
vapor-phase or liquid form with vacuum insulation and are available in different sizes
Automated Storage Units: These types of instruments typically use vapor-phase LN2 in
the specimen storage area, thus reducing contamination and safety risks associated with
handling liquid nitrogen, while still maintaining the steady temperature associated with
LN2-based storage Automated units, which can retrieve individual boxes without exposing
the entire rack to ambient conditions, can better protect non-target samples from transient
warming
High-Efficiency Units: These storage units have an offset lid that provides access to stored
space while maintaining a more vacuum-insulated surface compared to open-top units This
means that temperatures can be maintained at a more stable level compared to units with
open lids These instruments also have an interior turn tray, providing access to specimens
Liquid Storage Units: Medium to large in size, these units are designed for long-term
preservation of biological samples Many have auto-fill capabilities with temperature, LN2
level, and usage monitoring While these instruments provide convenience and consistency,
they need to be manually verified at regular intervals to ensure specimen integrity
Open-Top Storage Units: Despite being less expensive to purchase, these storage units
have higher operating costs and LN2 usage due to a large lid opening and additional heat
input The larger lid opening allows for easier access to your specimen, which is especially
useful for a high-throughput workflow
High Efficiency Units
Automated
Storage
Systems
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Dewars: Small, efficient, and transportable, these containers provide a stable storage temperature and low LN2 usage
While auto-fill models are available, most require manual filling of LN2 to maintain temperature They typically do not
have full monitoring and LN2 level control options, so you will need a higher level of manual management and verification
LN2 Supply Systems
LN2-The following supply systems should also be considered when designing your LN2 facility:
Bulk Supply Systems: Vacuum-jacketed withdrawal, piping, and valves are recommended to improve efficiency They
can also help increase safety by avoiding cold surfaces, condensation, and wet floors These systems require relief valves
to prevent pipe and bulk tank ruptures in the event of overpressure A line pressure gauge should be used as a reference
for pressure build events and troubleshooting
Portable Supply Tanks: These tanks require regular delivery depending on your LN2 storage unit LN2 volume and
pressure need to be continuously monitored to ensure adequate supply These tanks also require the LN2 storage unit
transfer house to be routinely disconnected and reconnected
SUMMARY
Designing and equipping a cryogenic storage facility can be a complicated process. While there are many factors to
consider, with careful planning and execution, you can ensure the safety of your specimens as well as your staff.
Azenta Life Sciences azenta.com 8
Did you know that a proper LN2 monitoring system can mean
the difference between life and death? Given that nitrogen
is lighter than air, it can rapidly displace oxygen in a room,
which can lead to asphyxiation To ensure the safety of your
facility, below are six factors you should consider:
1. Oxygen Monitoring: Oxygen monitors need to be in place
to notify staff of dangerous levels These systems should
be in areas that are exposed to LN2, clearly explaining
the nature of the alert and the associated risk In most
systems, there are multiple notification settings for various
oxygen levels to indicate slightly out-of-range conditions
versus significantly out-of-range conditions However, if
your oxygen monitor has only one alarm setting, it should
be set at 195% oxygen, the point at which staff need to be
evacuated immediately
Monitoring Your
LN2 Facility and
Storage Units
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2. Curved Mirrors and Camera: Having curved mirrors and cameras installed in your LN2 facility makes it easier to
perform visual inspections of LN2 storage units and identify staff during an emergency When positioned correctly,
mirrors and cameras can help observe if anyone has collapsed in the facility
3. Specimen Integrity Monitoring: Monitoring systems are key to preventing specimen loss Having a specimen
integrity monitoring system that will alert staff of urgent issues and provide insight into storage conditions, such
as temperature and functionality, is necessary Make sure you have redundant sources of monitoring in place, both
human and electronic, for added security
4. Temperature Monitoring: LN2 storage units need to have continuous temperature monitoring by a certified and
traceable thermometer Even when specimens are completely submerged, monitoring can provide reassurance that
a proper temperature is maintained if the LN2 level falls out of range In addition, you may want to place a redundant
thermometer at the highest level of where the specimens are stored
5. LN2 Level Monitoring: The LN2 level in each storage unit should be monitored and recorded manually to the nearest
quarter inch (025 inch or 6 mm) When performed manually, a plastic or metal yard stick is recommended Do not
use a hollow tube, as LN2 can rapidly shoot out of the top once inserted into the cold liquid nitrogen When using an
electronic component to measure LN2, the electronic level should be monitored and recorded The manually measured
LN2 level should be compared to the electronic level within a predefined acceptable range If out of range, calibrate
the electronic LN2 level to match the manually measured level
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SUMMARY
A well-monitored and safe LN2 facility is
critical to the long-term success of your
cryogenic storage. By putting in place a
comprehensive monitoring system, you
can have peace of mind that your staff
and specimens are properly protected.
6. LN2 Consumption Monitoring: LN2 consumption should
be measured and recorded manually (for manual-fill LN2
storage units) and electronically (for auto-fill LN2 storage
units) For manual-fill LN2 storage units, wireless remote,
weight-based monitoring systems provide continuous
measurements that can be precisely correlated to LN2
levels and used to determine evaporation rates On autofill LN2 storage units, the electronic monitoring system
provides this information Since auto-fill LN2 storage
units fill on an “as needed” basis, it can be difficult to
determine LN2 usage manually A clear acceptable range of
consumption with a calculated standard deviation should
be included, as identified by the manufacturer’s guidelines
and in accordance with the facility’s average usage
Azenta Life Sciences azenta.com 11
Installing and maintaining liquid nitrogen equipment can be
a daunting task, but it’s important to understand the basics
if you want your facility to run smoothly To help you get
started, below are key factors to consider
Installation and Setup
Installation and setup should be verified using manufacturer
recommendations for electrical and LN2 supply as well as
facility requirements Your storage unit should undergo a
set of qualification procedures to ensure that it is installed
correctly and meets all specifications:
Installation Qualification (IQ): Oversight and verification
of every physical aspect of the equipment (materials,
dimensions, pressure ratings) and components (operational
parameters, accuracy, voltage)
Installing and
Maintaining LN2
Equipment
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Operational Qualification (OQ): Testing each individual component, feature, and physical specification of the equipment
Performance Qualification (PQ) or IQ/OQ/PQ: Testing the operational requirements of the equipment under real-world
conditions
Electrical Power
While LN2-based cryogenic storage units are not dependent on electrical power for active cooling, it is required for
alarms and monitoring A backup power system with sufficient monitoring and alarm capabilities should also be in place
for when the facility is unattended
LN2 Supply: The LN2 supply system should contain enough LN2 for at least 21 days of normal usage and replenishment
intervals It’s a good idea to have a backup supply system in case the off-site provider is unable to re-supply within
this time frame In addition, your bulk tanks or cylinders as well as LN2 supply volume and pressure should be verified
regularly, and the LN2 connections should be routinely checked
Secondary Monitoring: When using secondary systems for monitoring temperature and LN2 levels, make sure to install,
calibrate, and verify before introducing samples
Pressure Relief Valves: These devices are essential when working with LN2 Because nitrogen gas buildup can lead to
an explosion, a risk mitigation plan must be in place Relief valves must be present on all storage units and components
that could trap LN2, and pressure relief valves should be piped to the outside, verified, and replaced regularly
Initial Fill: LN2 storage units must be filled with liquid nitrogen per manufacturer recommendations and stabilized up to
48 hours prior to introducing specimens An inventory rack system should also be installed at this time
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Calibration
Instrument calibration is a key step in ensuring accurate readings
Calibrated instruments are more reliable than those without any
adjustments, and they also provide better protection against
errors due to changes over time Records should include readings
taken both before and after calibration In addition, a record
that includes calibration date, name of who is performing the
calibration, name/serial number of the device used, and reference
to the SOP should be included
Verification
The installation and operation of cryogenic storage systems should be verified per manufacturer recommendations For
LN2-based systems, this includes installation qualification and components
Documentation: User manuals, certificates, maintenance logs, and factory acceptance documentation needs to be kept
in a central location that is available to staff
Personnel: Staff contact information should be made available and kept in a known location
Training and SOPs: A training program that includes safety procedures, routine verification process, and emergency
response plans should be in place for all staff members
Temperature Mapping: Temperature mapping of the storage unit is typically conducted by the manufacturer as part of
the design qualification To confirm the temperature within the unit, a secondary sensor should be used at the highest
level that specimens can be stored
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Routine Maintenance
The importance of performing system maintenance cannot be
underestimated It is essential to be in close communication
with manufacturers and service providers to develop
appropriate maintenance and verification schedules
LN2 Storage Units: Daily or weekly manual verification of
storage temperature, LN2 level, and usage is suggested Be
sure to keep records of manual verifications to watch for
trends or changes in system performance
Condensation, Frost, and Ice Buildup: Maintaining a
dry environment can reduce condensation, frost, and ice
accumulation, which impacts performance and usability To
improve efficiencies and equipment life, be sure to routinely
wipe surfaces and remove buildup
Thaw, Clean, and Dry: Periodic rounds of thawing, cleaning,
and drying may be required to maximize the efficiency and
lifespan of storage units Precautions should be taken to
ensure that samples are safely removed and stored securely
in another unit during the process
Backup Power: Given that batteries have a limited
shelf-life and should be replaced per manufacturer’s
recommendations, it is important to verify backup power
Azenta Life Sciences azenta.com 15
Alarms and Alerts: All alarm systems should be routinely
tested and verified The SOP should outline the process
for conducting system verification, and results should be
documented and made available for audits
Steps, Handles, and Lids: Interface components should be
routinely examined for deterioration and verified to ensure
functionality Lid gaskets should be inspected for sealing
and venting and replaced if damaged, as this can result in
inefficiencies
Plumbing: For auto-fill systems, plumbing should be regularly
verified and replaced per manufacturer’s recommendations
SUMMARY
As the need for cryogenic storage grows
in an organization, it’s important that
stakeholders understand the value of
proper installation and maintenance of
LN2-based systems. By following the
appropriate guidelines, repositories can
ensure that these systems are operated
safely and efficiently.
Azenta Life Sciences azenta.com 16
Cryogenic storage facilities face many potential threats—
from natural disasters to power outages and cyberattacks
Exposure of specimens to warming, even if transient, can lead
to degradation and significant loss of value Preparation is
key to effectively address emergencies when they occur and
minimize their impact to operations As such, an organization
with LN2 facilities should have written emergency plans for
disaster recovery, incident response, and business continuity
Staff should be provided copies of the plans as well as the
necessary training to execute them
Oxygen Sensors
Given that nitrogen can displace oxygen in an enclosed
environment, oxygen level sensors should be used in LN2
storage units Normal levels of oxygen should be ~21% Many
oxygen sensors have batteries or sensor cells that need
Ensuring Safety in
Your LN2 Facility
Azenta Life Sciences azenta.com 17
to be replaced and re-calibrated as instructed by the manufacturer They will also
have specific requirements as to the number of sensors needed based on the size of
the room, placement in the room, and height of the wall mounting Alarms should be
installed inside and outside of the room along with dedicated exhaust ventilation
Another option to consider is having viewing windows so it’s easy to determine if
the room is occupied during an alarm Fixed and mobile/personal monitors might be
appropriate depending on the size of your facility If installed units indicate an alarm,
it’s beneficial to use a personal monitor when entering the room in order to validate the
alarm, especially if you can’t see inside the area
Personal Protective Equipment (PPE)
Any staff that are working with or around LN2 should wear the appropriate protective
gear Safety goggles are required at all times and a face shield is necessary when
working with large volumes of LN2 Cryogenic gloves that are designed for use in
the vapor phase should never be immersed into liquid nitrogen and should be loosefitting for quick removal Disposable latex or nitrile gloves should also be used when
personnel share insulated gloves
A lab coat with long sleeves is required to minimize skin contact Pants should be worn
on the outside of shoes to prevent them from filling with LN2 in case of a spill, and an
apron is required when handling large amounts of liquid nitrogen When they are not in
use, PPE should be stored properly to avoid damage and contamination
Azenta Life Sciences azenta.com 18
Training Ensures Safety and Specimen Quality
Training your staff is essential so they can perform their required tasks safely It also ensures quality in specimen
handling It’s recommended that you document and repeat training on a yearly basis
In general, all staff must be aware of occupational hazards and be fully trained in the procedures for usage, storage,
and transportation of LN2 before they are allowed to handle it In addition, appropriate training for the safe handling of
cryogenics should be provided Staff should be trained on how to respond to alarms and procedures, both for accurate
recording as well as resolution
The retrieval of specimens from cryostorage also requires specific training due to the risk of explosion For example,
when liquid nitrogen enters an improperly sealed glass storage vial, the gas expands rapidly as the vials are brought to
room temperature, resulting in the potential for explosions
SUMMARY
A safe and accident-free work environment is the top priority for any organization. While LN2-based systems can
provide highly reliable storage for critical materials, there are serious risks that managers must address. Following
these tips and guidelines will help promote safety and compliance in your liquid nitrogen facility.
Azenta Life Sciences azenta.com 19
Cryogenic storage facilities face many potential threats—
from natural disasters to power outages and cyberattacks
Exposure of specimens to warming, even if transient, can lead
to degradation and significant loss of value Preparation is
key to effectively address emergencies when they occur and
minimize their impact to operations As such, an organization
with LN2 facilities should have written emergency plans for
disaster recovery, incident response, and business continuity
Staff should be provided copies of the plans as well as the
necessary training to execute them
On Call Staff
Key personnel should be identified for responding to
emergencies These individuals must be trained and qualified
to handle situations associated with LN2-based specimen
storage Emergency contact numbers should be in a central
Preparing Your
LN2 Facility for an
Emergency
Azenta Life Sciences azenta.com 20
location so they can be notified quickly if needed; this information should also be posted near notable areas such
as at reception desks
Staff should have a check list of procedures to follow during an emergency with telephone numbers for professional
assistance They should also be familiar with how to operate key equipment during an emergency
Backup Capacity
In case of equipment failure, it’s recommended to have backup capacity for your LN2 units The extra-capacity
equipment you have in your facility should be the same capacity as your largest single LN2 storage unit and
maintained at operating temperature If space isn’t available, explore whether nearby facilities can accommodate
temporary storage of specimens during an emergency In addition, LN2, dry ice, and/or portable freezers should
be available at your facility to maintain specimens during the transfer It’s also important to have sufficient backup
power for your storage and monitoring equipment
LN2 cryogenic facilities should have written emergency procedures for transferring specimens from a failed/
malfunctioning unit as well as for returning those specimens to their original location once it is safe to do so Within
these written procedures should be the LN2 storage unit name, number, and location of where specimens have
been relocated
Other Best Practices for Risk Mitigation
Communication with Utility Companies: It’s important to be in close contact with local power companies to
ensure that that the facility is considered “high priority” for power restoration following an emergency
Azenta Life Sciences azenta.com 21
Emergency Drills: Where possible, emergencies should be simulated
to ensure proper follow-through for the established emergency plan
LN2 Refill: In the event of an impending need for evacuation,
repositories that utilize LN2 bulk tanks should arrange to have them
filled
Storing Records On-Site: If inventory systems are housed on a server
offsite, it may be wise to consider storing electronic records at the
facility to ensure that they are accessible in case of an emergency
Sample Collection Redundancy and Splitting: To ensure that the
most valuable specimens are not lost, duplicates can be kept in
different storage units or at separate sites Sample collections can
also be divided across multiple units or locations to minimize the risk
of losing an entire collection from one event
SUMMARY
Emergency planning is critical for any business, and this is especially true
for those storing cryopreserved materials. In the event of an emergency, it’s
imperative to have a plan in place so that you can minimize damage and get
back up and running as soon as possible.
Azenta Life Sciences azenta.com 22
Starting and running a cryogenic storage facility requires
careful planning and robust operating procedures to ensure
reliable long-term protection of critical materials Following
the recommended measures mentioned here will significantly
mitigate risk to your sample collection and staff
Most LN2-based storage systems are operated manually:
sample retrieval is performed by hand and inventory is
managed with basic tools like spreadsheets This can lead to
variability, human error, and inefficiencies4
Automation can
address many of these drawbacks using robotics to retrieve
samples and built-in software to track inventory, leading to
better sample quality and simpler data management (see box
to the right)
Since cryogenic storage facilities require not only expertise
but also significant investment in capital, staff, and
training, many organizations decide to outsource Working
with a capable external partner can greatly streamline
ultracold storage and management, especially for regulated
environments (see box to the right)
Conclusion
Automated Systems
The CryoArc™ -190°C LN2-Based
Automated Storage Systems offer
the greatest sample protection
and comprehensive inventory
management and control with a
superior user experience at an
affordable price Targeted and nontargeted samples are protected
from warming above Tg throughout
sample retrieval Quality is assured
by viewing user access, sample
inventory, history, and audit-trail
reports Emergency protection
provides greater than 20 days of
temperature stability in the case of
energy or LN2 loss
LEARN MORE →
Ultracold Storage and Distribution of Cellular Products and
Samples
Managing sensitive materials like cellular therapies—including
storage, transportation, and tracking—requires robust and
adaptable systems to ensure safety, integrity, and regulatory
compliance that are essential for FDA review We specialize in
cGMP (Current Good Manufacturing Practice) controlled cold
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Azenta Life Sciences azenta.com 23
Streamline your Cryogenic Storage with
Azenta Life Sciences
Azenta Life Sciences has deep application experience, proven technologies, and a
global infrastructure to protect the integrity of cryogenic materials and provide precise
inventory accuracy and documentation If you’re in the process of planning your LN2
facility or want to store your samples at our certified facilities, we can help
CONTACT AN EXPERT →
References
1 Best Practices: Recommendations for Repositories (4th ed), Addendum 1: Liquid Nitrogen-Based Cryogenic Storage of Specimens ISBER 2019
References for “Streamline Your Cryogenic Storage with Azenta Life Sciences”
1 Hubel, A, Spindler, R & Skubitz, A P N Storage of Human Biospecimens: Selection of the Optimal Storage Temperature Biopreservation and Biobanking vol 12 165–175
(2014)
2 Best Practices: Recommendations for Repositories (4th ed) ISBER 2018
3 Best Practices: Recommendations for Repositories (4th ed), Addendum 1: Liquid Nitrogen-Based Cryogenic Storage of Specimens ISBER 2019
4 Why Automate? Explore the Benefits of Automated Sample Storage Azenta Life Sciences 2022 https://wwwazentacom/blog/why-automate-explore-benefits-automated-sample-storage
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