Laboratory Safety Manual - Chapter 19: Research Laboratory Freezer Alarm Policy

Title

Laboratory Safety Manual - Chapter 19: Research Laboratory Freezer Alarm Policy

Table of Contents

1. Introduction
2. Types of Fridges and Freezers
3. Monitoring
4. Safe Handling and Operating Procedures
   1. Installation
   2. Signage Requirements
   3. Maintenance
   4. De-frosting
   5. Inventory
   6. Moving
5. Frequently Asked Questions

I. Introduction

The purpose of this policy is to establish guidelines for all University departments relating to laboratory refrigerators (fridges) and freezers on campus. This policy includes the request for installation of fridges and freezers, freezer alarms, maintenance, and safe handling and operating considerations for this equipment.

The previous version of this chapter covered how to request, operate, and monitor freezer alarms from UNC-Chapel Hill Facilities Life Safety and Electronics Shop. As of March 2025, Facilities Life Safety and Electronics Shop released a Freezer Alarm Monitoring Phase Out that retires previously covered freezer alarms due to the migration to a new alarm network. If you currently have a freezer alarm monitored by Life Safety and Electronics Shop, please begin investigating alternative options for monitoring services. When transitioning to your new monitoring system please call the Work Reception Department (919) 962-3456 for Facilities to disconnect your freezer(s) from and secure the old alarm panel.

II. Types of Fridges and Freezers

Domestic Use

There are several types of potential refrigerators and freezers that can be utilized in the laboratory. Standard household (“Domestic use”, Figure 19.1) refrigerators and freezers are not typically suitable for a laboratory environment but can be used to store non-hazardous materials along with BSL-1 materials and/or aqueous solutions. Domestic use refrigerators and freezers cannot be used to store flammable materials and food and drink are not allowed in laboratory designated use refrigerators and freezers. These should be labeled, “Not for flammable storage. No food or drink. Lab use only.” See Section IV b. for more information on Signage Requirements.

Figure 19.1. Example of domestic use refrigerators and freezers.

Flammable Materials

Flammable material refrigerators and freezers (Figure 19.2) are specifically designed for the storage of flammable solids and liquids. These fridges and freezer have the compressor and other circuits located outside of the unit (typically at the top) and do not have internal switching or wiring. This reduces the potential for ignition of flammable vapors. These fridges and freezers are typically marked for “Flammable Material Storage,” by the manufacturer and also have other features including thresholds, self-closing doors, magnetic door gaskets, and special inner shell materials to help limit damage should an exothermic reaction occur.

Figure 19.2. Example of a flammable material rated refrigerator.

Explosion Proof

Explosion proof refrigerators (Figure 19.3) are not typically necessary in a laboratory setting but can be purchased if the laboratory does have the need for it. Explosion proof refrigerators have both spark-free interior and exterior, where all electrical components are typically housed inside a protected enclosure. These can typically be found in solvent dispensing rooms where not only can the contents be highly flammable or explosive, but also the surrounding atmosphere could potentially contain highly flammable vapors.

Figure 19.4. Example of an ULT freezer.

III. Monitoring

As of March 2025, Facilities Life Safety and Electronics Shop released a Freezer Alarm Monitoring Phase Out of the previously covered freezer alarms due to the migration to a new alarm network. If you currently have a freezer alarm monitored by Life Safety and Electronics Shop, please begin investigating alternative options for monitoring services. When transitioning to your new monitoring system please call the Work Reception Department (919) 962-3456 for Facilities to disconnect your freezer(s) from and secure the old alarm panel.

A. Responsibility

1. It is laboratory or department responsibility to identify a proper alarm system that functions with the lab’s requirements and designated needs. External third-party monitoring systems such as Minus80Monitoring or Barlow can be utilized.
2. The cost of installation is the responsibility of the laboratory or department.
3. The laboratory should have a procedure or process in place regarding the alarm system if it does go off and what to do in this type of emergency situation including contacting any required University contacts like EHS (919-962-5507).

B. System Maintenance

1. The cost of service, repair, and the preventative maintenance inspections, recommended to be conducted tri-annually, are the responsibility of the laboratory or department owning the alarm system.
2. The external third-party alarm monitoring system used should include regular tests and inspections for:
   1. Proper system operation
   2. System back-up battery inspection
   3. System communications inspection
   4. Audit of emergency personnel notification data

C. Alarm Response

1. The laboratory is required to have a procedure and process in place for alarm response that the laboratory will follow for different situations including if the freezer or fridge goes down.
2. Until the freezer alarm phase-out is complete, UNC Police response to freezer alarms will be in accordance with UNC Police General Orders. These policies are available by contacting the UNC-Chapel Hill Chief of Police.
3. It is the responsibility of the individual department to provide the Life Safety Electronics Shop with up-to-date contact information for all alarm systems. This information is required as soon as changes are made.

IV. Safe Handling and Operating Procedures

A. Installation

When purchasing a laboratory refrigerator or freezer, consider the materials that will need to be stored inside of the fridge or freezer to determine the type that can be purchased. If any flammable materials need to be stored inside of a fridge or freezer, a flammable-rated one should be purchased.

When determining placement of a laboratory refrigerator or freezer, consider the location of outlets, surrounding equipment, egress, and access to electrical panels or emergency equipment. Note that large equipment may require its own outlet or may need a 20-amp circuit if one is not already available in the laboratory. Large equipment cannot be plugged into a power strip or extension cord. Additionally, fridges and freezers can generate a significant amount of heat, so ensure there is at least six inches of clearance between walls and other equipment and at least eight inches of overhead clearance to ensure the equipment does not overheat. Do not store cardboard boxes or other flammable or combustible materials on top or near a fridge or freezers, as this presents a fire hazard.

Fridges and freezers should be stored within laboratory space, not in open hallways, as this presents additional safety and security concerns. Circumstances where fridges and freezers may be stored in the hallway must be cleared with EHS and will require a protocol for ensuring safety and security of the research materials. If you notice that a fridge or freezer has been installed that potentially blocks egress (minimum of at least three feet of clearance to evacuate), notify EHS (919-962-5507) immediately.

B. Signage Requirements

Laboratory designated refrigerators and freezers are required to have signage stating “No Food or Drinks,” or a variation of this including “Lab Use Only.” If a laboratory fridge or freezer is not rated for flammable materials the signage should include, “No Flammable Materials Storage.” Templates for this signage are available online at the EHS Safety Signage website. All flammable rated refrigerators and freezers should have a sign from the manufacturer stating, “Flammable Material Allowed,” or a variation of a flammable rating sign on the front.

All laboratory fridges and freezers are required to list the PI and emergency contacts directly on the front door. This sign must include up-to-date contact information and after hours contact information in the event of an emergency. If the fridge or freezer is shared between multiple laboratories, all responsible PIs and designated safety supervisors should be listed.

Laboratory refrigerators and freezers used to store other hazardous materials (i.e., biological, radiological) should have the associated hazard symbol(s) located on the front of the door.

C. Maintenance

Laboratories and departments are fully responsible for all maintenance and upkeep of their fridges and freezers. It is recommended to perform user-level maintenance of fridges and freezers at least every 6 months. This can include wiping down the outside of the equipment, cleaning filters and condenser coils regularly (done by a technician), removing ice from the gasket and doors with a soft cloth, and keeping the doors shut and free of ice and frost. Scheduled maintenance with a vendor can be helpful in prolonging the life of a fridge and freezer. Additionally, keeping an organized and inventoried fridge and freezer can also prolong the life of the equipment. See the section on Inventory for more information.

If there are any complex issues, please contact a service technician for assistance. See the following section on De-Frosting; appropriate guidance regarding this can depend on the type of fridge or freezer. Please be aware that the freon line can be punctured inside of domestic use and non-rated fridges and freezers resulting in potential exposure and loss of equipment and/or research materials.

D. De-Frosting

The following guidelines are for de-frosting a fridge or freezer. Note that while de-frosting a fridge or freezer, all proper personal protective equipment (PPE) including lab coat, safety eye protection, and appropriate gloves and cold gloves are required. It is recommended that goggles or a face-shield be worn when de-frosting and cleaning out a fridge or freezer due to potential splashing hazards.

1. Before too heavy of ice build up occurs, schedule a de-frost time for the laboratory. Do not attempt de-frosting a fridge or a freezer alone. Contact EHS if additional guidance is needed regarding de-frosting fridges or freezers.
2. If possible, utilize a backup freezer or fridge for temporarily storage and move all items to this backup equipment.
   1. When moving items, utilize appropriate secondary containment. Dispose of any leaking or broken containers appropriately to prevent additional issues.
   2. If a container has leaked into the ice, contact EHS immediately (919-962-5507) and stop the process of de-frosting.
   3. If a backup fridge or freezer is unavailable to the laboratory, plan for potential temporary cold storage utilizing dry ice or dry ice/acetone baths to assist with keeping items cold.
3. Once all items are removed, unplug the fridge or freezer to defrost.
   1. Place absorbent materials (e.g., spill pads) beneath the freezer to catch the water. Lighter absorbent materials like bench paper or paper towels may not absorb all of the water and can potentially splash when being picked up.
   2. Turn off the unit (if possible) and open the door.
      1. If the fridge or freezer has a slight odor and chemical fume hoods are available in the same room, open the chemical fume hood’s sash and place on emergency exhaust.
      2. If a fridge or freezer has built up a lot of vapors or odors, contact EHS for additional guidance, as this may need to be removed from the laboratory space to vent.
4. Let the ice melt completely.
   1. Bulk ice can be removed occasionally using an ice scraper on areas where there are no electrical components. Use caution and do not use force or a sharp object.
   2. Never use a sharp object to remove ice from a gasket or a door as this can puncture refrigerant piping and lead to a chemical exposure. If this situation occurs, immediately close the equipment’s door and evacuate the room. After the room is evacuated and secured, notify your supervisor and contact EHS.
   3. Remember to wear all proper PPE (lab coat, safety eye wear, appropriate cryogloves, etc.) to protect yourself from potential freezer burn and any samples that may be lost or trapped in ice.
5. Once the fridge and freezer has come to room temperature (approx. 24 hours), you can clean the interior with warm water and soap.
6. Wait until the fridge or freezer is completely dry before plugging it back in. Note that it may up to 12 hours or longer for a fridge or freezer to cool back down to its regular operating temperature.
7. If you notice that your fridge or freezer continues to build-up ice frequently after de-frosting, there may be an additional issue with the fridge and freezer that a technician or the manufacturer needs to assess. Contact the manufacturer or a technician if this is the case.

E. Inventory

An inventory for all refrigerators and freezers must be maintained by every laboratory. Refrigerators and freezers must be documented in the Laboratory Safety Plan floor plans as well. Please remember to update these floor plans when equipment is added or removed from a space. If a laboratory stores any hazardous materials or samples (i.e., chemical, biological, radiological) outside of their typical laboratory in another refrigerator or freezer on campus, documentation is required for the storage of these materials in a laboratory safety plan even if they are only being stored temporarily.

Having an up-to-date and accurate inventory will help improve research efficiency and reduce the purchase of duplicate reagents. Inventories also provide safety and security of research reagents and samples and can be done in a variety of ways. Inventories can be a simple excel spreadsheet that is shared amongst the laboratory, or a third-party inventory software can be utilized. Annual inventory is required for chemicals and for some biological agents and radiological agents, more frequent inventory is required. See the Biosafety Manual Chapter 14 on Select Agents and Toxins  and the Radiation Safety Manual Chapter 05 on Radiation Source Inventory for more information on additional inventory requirements.

When performing an inventory of a fridge or freezer,

• Wear all proper PPE (lab coat, safety eyewear, appropriate gloves) when performing an inventory.
• Go through all containers, account for each one, and update the inventory accordingly. Ensure that the containers are organized and clearly labeled.
  • It may help to organize fridges and freezers utilizing secondary containment to store laboratory samples or similar hazardous materials.
• Remove any old, unwanted, leaking, broken, unnecessary, or unlabeled containers and materials and dispose according to the Laboratory Waste Management Plan, Biological Waste Disposal Policy, or the Radiation Safety Manual Disposal Policy.
  • Use caution when disposing of sealed containers with frozen contents. The thawing process can potentially cause the tubes to rupture, and this can be especially dangerous if multiple lidded containers are planned to be autoclaved. EHS can advise on safety precautions when large quantities of hazardous material need to be disposed of.
  • If the laboratory finds or identifies controlled substances, contact EHS for proper disposal procedures.

F. Moving and Surplus

If the laboratory plans to move to another space on campus or another laboratory, please see the Vacating/Moving Laboratory Space Procedure. In regards to refrigerators and freezers, follow the de-frosting procedures above and decontaminate the refrigerator or freezer appropriately. If the refrigerator or freezer is utilized with biological material, utilize a 10% fresh bleach solution with a minimum contact time of 10 minutes and then subsequently wipe down the inside and outside. If used with chemical materials, warm water and soap can be used to wipe down the inside. If the fridge or freezer was used with radioactive materials, this must be decontaminated and surveyed in accordance with the Radiation Safety. Contact Radiation Safety for guidance. After decontamination of the inside and outside of the fridge/freezer, ensure that all hazard labels are removed or properly defaced.

Some moving companies contracted by departments will allow for the move of fridge/freezers with research materials still inside. If this is the case, securely contain and package the materials inside of the fridge/freezer using secondary containment. The outside of the fridge/freezer should then be decontaminated appropriately and then taped and shrink-wrapped shut. Make sure the vendor/mover is contacted prior to the move to ensure that they allow this and contact EHS for additional information and guidance.

If the fridge/freezer will be sent to Surplus, all materials inside the fridge/freezer must be removed and disposed of appropriately or stored in another appropriate place. The fridge/freezer must be de-frosted and decontaminated (inside and outside) using appropriate procedures and all hazard labels then removed or defaced. If the fridge/freezer has freon, submit a work order to Facilities Services to remove the freon. If you are unsure whether the fridge/freezer contains freon, contact the Facilities Services Refrigeration Shop (919-962-1087). The laboratory and department are responsible for all charges associated with freon removal. Once this has been completed, contact EHS for Safety Clearance Sticker and schedule a pick-up with UNC Surplus.

If the fridge/freezer will be given to another laboratory or left in the laboratory for future use, follow all proper removal and/or disposal of hazardous materials, decontaminate (inside and outside) the fridge/freezer using appropriate procedures, and remove and deface all labels.

V. Frequently Asked Questions (FAQs)

1. What needs to be considered when purchasing a fridge/freezer for research purposes?

The best type of fridge/freezer for your laboratory will depend on the materials you plan to store in it and the space you have available. For example:

• Cold storage of flammable materials requires specialized equipment that eliminates potential ignition sources (i.e., flammable material units and explosion-proof units).
• The use of a household (“domestic”) fridge/freezer may be sufficient for the storage of non-hazardous laboratory reagents; however, this is not recommended if your research could potentially require cold storage of flammable materials in the future.

Prior to placing the equipment, the lab should consider the location of outlets and egress routes. Additional considerations include:

• Large equipment should be plugged directly into a wall outlet—maintaining this equipment on a power strip or extension cord is not acceptable with NC fire code.
• Storing a fridge or freezer outside of laboratory space (e.g., hallways) is typically not acceptable; attenuating circumstances must be cleared by EHS and will need a protocol for ensuring the security of research materials and reagents.

2. What else does my refrigerator/freezer need to be in compliance with UNC policies?

Your equipment will need to be labeled appropriately. Appropriate labeling includes:

• A sign listing the responsible PI(s) and emergency contact(s)
• A label indicating no food/beverages intended for human consumption
• Domestic refrigerators must indicate flammable material storage is NOT permitted
• Labels reflecting any other hazards of fridge/freezer’s contents (e.g., biological hazards, radiological hazards, flammable material storage.

3. Can we keep snacks in our laboratory fridges/freezers?

No. Any fridges/freezers that are intended to be used for human food/beverage should be located at least 3 feet away from laboratory workspace, have an appropriate label, and cannot be used for other laboratory reagents.

4. We store sensitive research materials in our fridges/freezers; how do we ensure they remain in the appropriate temperature range?

UNC Facilities Life Safety and Electronics Shop no longer offers installation of freezer monitors and are phasing out monitoring of current systems. Some vendors offer real-time temperature monitoring (e.g., Minus80). Please be aware the laboratory is responsible for all costs associated with these services.

5. We plan to move to a new laboratory space on campus; how do we prepare our fridges/freezers for transit?

Please see Laboratory Closeout and Move Instructions.

1. Prior to vacating or relocating laboratory space at UNC, you must provide written notification to EHS Chemical Safety Team.
2. Once the lab has discussed the move with EHS, the lab should, empty their refrigerators/freezers, defrost them, and decontaminate them (inside and outside) with an appropriate disinfectant. Any reagents or research materials that will not be kept after the move must be properly disposed of.
   1. Please be aware that fridges/freezers used for radioactive materials must also be surveyed to ensure adequate decontamination.
   2. If fridge/freezer can be moved with research materials still inside (contact mover/vendor), the material in the equipment must be securely packed in secondary containment. The outside must be decontaminated and the equipment must be taped or shrink-wrapped shut.
3. After emptying and decontaminating the fridge/freezer, attach a completed Safety Clearance Sticker.  
4. Contact Facilities Services (or your moving company) to move the equipment.
   1. Alternatively, if the lab does not want to retain the fridge/freezer, they may surplus this equipment (see answer to FAQ 7).

6. Our lab is in the process of closing out; what should we do with our fridges/freezers?

Follow the same guidance as FAQ 5 #1-3.

In addition to emptying, defrosting, and decontaminating your equipment, any hazard labels must also be removed or defaced. Once all this is done, the lab can donate the equipment to another group who wants it or prepare it for UNC Surplus (see FAQ 7).

7. How do we prepare a fridge/freezer for UNC Surplus?

 The lab will need to:

1. Empty, defrost, and decontaminate the equipment 
2. Remove or deface all hazard labels
3. Contact Facilities Services Refrigeration Shop (2-1087) to determine if refrigerant needs to be removed
   1. If refrigerant needs to be removed, submit a work order to Facilities Services Customer Service (2-3456); please note, the Department/owner pays for removal.
4. Once the above has been completed, contact EHS for a Safety Clearance Form
5. Schedule a pickup with UNC Surplus

 

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