• Cracking the Code — Explaining UN Ratings
  • Monica

    Monica Martens is a Technical Services Specialist at New Pig. Her primary responsibilities are to help solve customers' leak and spill problems and answer tough reg-related and spill response questions.

  • Samsays:
    01/23/2014 at 8:08 pm Reply

    hi, what is difference between T- rating and x-rating regarding OVERPACK salvage drum? is T-rating part of X- rating? or vice versa? When is actually specific T-rating required? thx. for your feedback.

    • Monicasays:
      01/24/2014 at 12:54 pm Reply

      T rated drums are usually 85 gallon steel drums, though less commonly smaller drums can be tested to be designated a T rating. This means that the drum was tested specifically to be T rated, and can be used as a salvage drum for leaking or damaged steel, poly or fiber drums, containing liquids or solids. It is a required rating to use in other countries when used for leaking drums, but not in the US at this point. So almost any leaking drum should be able to be placed in an appropriately rated T rated salvage drum, and be assured it is not going to leak.

      X rated overpaks may be able to be used to overpak but not necessarily if the drum is shipping to another country. In that case they would likely need a t rated drum.

  • David Oberholtzersays:
    07/11/2014 at 2:17 pm Reply

    Can I use a drum with a UN rating for liquids for a solid hazardous material? Is there a statement in the DOT regulations that states this?

    • Jensays:
      07/25/2014 at 8:17 am Reply

      Usually drums need to be specifically rated for what is contained inside of them. Unless they are dual rated for solids and liquids, they can only be used for what they are rated for. However, under certain circumstances, HazMat solids MAY be packaged into drums that were only tested with liquids. For this, 49CFR 173.24a(b)(3) may be of some help.

      Hope this info helps! Please leave another comment if you have any other questions.

  • Fiosays:
    09/10/2014 at 10:30 am Reply

    I have a question about UN containers in Canada.
    To be available to sell UN rated containers, companies in Canada need to be Certified in ISO9001:2008, is that true?

    • Jensays:
      09/12/2014 at 1:01 pm Reply

      Hi Fio,

      No. ISO 9001: 2008 is a voluntary consensus standard in the United States and Canada. The standard presents a framework for benchmarking an organization’s quality management system.

  • Dansays:
    01/16/2015 at 1:05 pm Reply

    What formula is used to determine what the specific gravity marking on the drum should be based on the product that is going in the drum.

    • Monicasays:
      01/19/2015 at 10:06 am Reply

      Hi Dan,
      You can check the SDS for the product to find the specific gravity of the liquid that is going in the drum.
      If you have a waste that is mixed, you can calculate the specific gravity:

      • Weigh a container and note the weight
      • Add a specific amount of water at a 60F temp (1000 mils @ 60F)
      • Subtract the weight of the container to find the weight of the water
      • Do the same for the chemical or waste at the same amount (1000 mils) and temperature (60F)

      Note: Temperature, pressure, and amount must be the same on both the water and chemical being tested to get an accurate reading.
      The specific gravity (relative density) is the ratio of the density of a material compared to the density of water at a specific temperature and pressure.
      Divide the weight of the chemical by the weight of the water. The specific gravity of the chemical is then approximately XYZ at 60 degrees Fahrenheit.
      The specific gravity rating on the drum has to be equal to or greater than the specific gravity of the liquid being shipped. Therefore, if a drum rating has a specific gravity of 1.8 (example: UN 1A1/X1.8/300), the specific gravity of your chemical can be 1.8 or less for this container, but it cannot be over 1.8.
      Hope this helps! If you have more questions, please let us know.

  • Nickey Hodgessays:
    01/30/2015 at 11:11 am Reply

    Can you store drinking water in UN rated plastic barrel?

    • Monicasays:
      01/30/2015 at 2:46 pm Reply

      Hi Nickey,
      The issue with storing drinking water has nothing to do with the UN rating; it has to do with the material the container is made of.
      The UN rating is specific for shipping hazardous materials or wastes. As long as the drum is designed for drinking water, meaning **Made from USDA and FDA approved resins for direct containment with food products**, and is compatible with the material, it is suitable for storage of drinking water. (In this case, a poly drum with drinking water, like our DRM1136.) Compatibility of the material with the drum is key, and for food/drinking water the material must be made from USDA and FDA approved resins.
      I hope this helps! Please let me know if you have any other questions.

  • Lorraine Jsays:
    05/04/2015 at 2:08 pm Reply

    What kind of a drum do I need for Trifluoroacetic Acid.

    • Brittany Svobodasays:
      05/07/2015 at 8:43 am Reply

      Hi Lorraine, thank so much for your comment.

      You will need to choose a drum that is compatible with that liquid. It is the responsibility of the shipper to determine whether or not the container is compatible. Anyone choosing in container or preparing hazardous materials for shipment must have proper DOT hazmat training. In many cases that would be a polyethylene drum.


  • Montysays:
    05/20/2015 at 10:52 am Reply

    Are there any open head plastic drums (1H2) for use with liquids?

    Also, is this statement listed in the information you provide correct?

    “For example, using the designations above, a rating of UN 1H1/Y1.9/100 means that this is a drum (1), that it’s plastic (H), and open head (1).”

    Shouldn’t it be closed head (1)?

    • Karen Hamelsays:
      05/21/2015 at 8:54 am Reply

      Hi Monty, thanks so much for your comment and great catch!
      You are correct: the second (1) in the UN number means that it is a closed head container, not open head.
      When it comes to open head poly containers rated for liquids, there aren’t many in the market – especially over 30 gallons. We do stock a 5 gallon polyethylene pail that is rated for packing groups II and III liquids with specific gravities up to 1.5. We don’t stock it, but we can special a 30 gallon open head poly drum for liquids. But, it is only good for packing group III liquids with specific gravities up to 1.2.
      If you have the need to ship bulk liquids, we also offer poly IBC containers that are rated for shipping packing group II and III liquids.
      Please leave another comment if you have any other questions or concerns.

  • Arnaudsays:
    08/06/2015 at 8:07 am Reply

    Regarding the hydrostatic pressure, what is the unit? relative or absolute pressure?

    • Brittany Svobodasays:
      08/10/2015 at 8:15 am Reply

      Hi Arnaud,

      It is the relative pressure, measured in kilopascals (kPa).


  • eileensays:
    09/01/2015 at 3:10 pm Reply

    I am trying to assess what the UN rating would be for a container that I can use for a certain chemical. I got the first 4 characters that I need but I am not sure how to get the specific gravity and hydrostatic pressure.
    Let’s say my chemical has a density of 0.95 g/cm3 at 20 °C and a vapor pressure of 5.27 hPa at 20 °C(68 °F).
    What would be the appropriate designations for specific gravity and hydrostatic pressure? thank you and really appreciate your response.

    • Karen Hamelsays:
      09/02/2015 at 11:59 am Reply

      Hi Eileen,
      Thank you so much for your comment. When looking at a UN rating on containers, the specific gravity (or relative density) of the liquid refers to its density when compared to water. Water has a specific gravity of 1.0. From the information that you provided above, your chemical is slightly less dense than water.
      If you need to find the specific gravity of other liquids at your facility, you can weigh one gallon of the liquid and divide that weight by 8.33 (the weight of a gallon of water.) The resulting number is the specific gravity. For example, if you weigh a gallon of the liquid and it weighs 12 pounds:
      12 / 8.33 = 1.44 specific gravity
      Once you know the specific gravity of the liquid that you’ll be shipping, the number that follows the “X”, “Y”, or “Z” in the UN rating relates directly to the specific gravity – if the container is rated for shipping liquids. The number will be between 1.0 and 2.0. For example, in the UN marking below, the specific gravity is 1.8. That means that the liquid being shipped can have a specific gravity up to 1.8.
      The hydrostatic pressure rating is listed after the specific gravity marking, and refers the maximum internal pressure rating that the drum is tested to withstand. The unit of measure for this marking is kilopascals.
      In the information that you provided above, you list the vapor pressure rating as 5.27 hPa. 1 hPa = 0.1 kPa. So, the pressure rating in kPa is 0.527 kPa. Like the specific gravity rating, as long as the liquid being shipped does not exceed the hydrostatic pressure rating, it may be shipped in the container if all of the other qualifications (packing group, compatibility, etc.) have been matched.
      If you have any other questions, comments or concerns, do not hesitate to reach out!

  • Mikesays:
    09/04/2015 at 3:10 pm Reply

    I believe you have a typo:

    “A closed-head drum, or drum with no removable top would be designated with a 1.” (Immediately following the container material listings)

    “…that this is a drum (1), that it’s plastic (H), and open head (1).” (Liquids drum explanation.)

    • Brittanysays:
      09/08/2015 at 5:22 pm Reply

      Hi Mike,
      Thanks so much for your comment and calling out the error. You’ll find the information corrected above.
      Do not hesitate to reach out with any other questions, comments or concerns.

  • Janet Heetersays:
    12/02/2015 at 10:01 am Reply

    I have old phone cases with lithium metal batteries fully enclosed in the hard plastic of the phone case. These are apparently UN3901 Packing Group II. But, what does that mean as far as a shipping container? We wanted to use 5 gallon plastic buckets with snap on lids. Will that suffice?

    • Brittanysays:
      12/04/2015 at 2:39 pm Reply

      Hi Janet,

      Thank you for your comment!

      It depends on whether or not the bucket you’re using has an appropriate UN marking. From your description, this is a Packing Group II material. That means that you’ll need a container that is either X or Y rated. If it has a “Z” in the UN number, or if it doesn’t have a UN number on it, you won’t be able to use it for shipping. Fortunately, it’s not hard to find 5-gallon containers with either of those ratings. The UN rating will be stamped somewhere on the container. On a 5-gallon pail, it’s usually on the bottom. On larger containers, it’s typically on the side.

      Next, you’ll need to make sure that you aren’t exceeding the maximum shipping weight that the UN rating allows. This allowable weight is shown right beside the “X” or “Y”, and it is in kilograms. (To determine the amount in pounds, divide the number by 2.2). As long as the weight of the container and phone cases together does not exceed this amount, you are in compliance with that part of the shipping requirement.

      The “UN3901” will be used on the manifest as a way to identify the material. Remember that DOT requires anyone shipping hazardous materials, preparing hazardous materials shipments for transport and signing manifests to be properly trained.

      Hope this answers your questions! If not, feel free to leave another comment and we will work to get you the information you need!


  • Kevinsays:
    12/04/2015 at 5:39 pm Reply

    Hi there. After scrolling through previous questions, you mention there are not many available open top poly drums for shipping hazardous liquids. What if the material being transferred is non-hazardous? For example, can I use an open top poly 55 gallon drum to ship water?


    • Brittanysays:
      12/10/2015 at 11:25 am Reply

      Hi Kevin,

      Thank you for your comment! UN-rated containers are only required when hazardous materials are being shipped. Since water isn’t hazardous, in theory you should be able to ship it in an open head drum.

      Hope this helps!

      Do not hesitate to leave another comment if you have any other questions.


  • Al madridsays:
    12/15/2015 at 5:28 pm Reply

    What’s the rating for methylene chloride packing in a poly drum . And how do you read this in rating? USA/R1874/15 RL?

    • Brittanysays:
      12/21/2015 at 11:54 am Reply

      Hi Al,

      Most poly drums are made of polyethylene, which is not compatible with methylene chloride. Therefore, poly drums would not be an appropriate shipping container for methylene chloride. In DOT Hazmat Employee training, one of the things that you are taught is to choose a drum (or container) that is compatible with the materials being shipped. As a DOT hazmat employee, you would be trained to locate the packing group for methylene chloride in the DOT Hazardous Materials Table [49 CFR 172.101]. (the proper shipping name is actually “dichloromethane”).

      The part of the rating that you listed USA/R1874/15 RL is actually only half of the UN rating. The “USA” tells you the container’s country of origin. The rest of the information is the manufacturer’s code.

      Hope this info helps! If you have any other questions, please leave another comment.


  • Gregsays:
    02/01/2016 at 8:36 pm Reply

    I have a Group II (Y) Product with a rate SG of 1.8 , I want to use a Group I ( X) Package with a SG rating of 1.4 . Is this rating equivalent a Y 2.1 , and if so can I use the X1.4 with the Y1.9 rated product .

    • Brittanysays:
      02/01/2016 at 8:38 pm Reply

      Hi Greg,

      Thank you for your comment!

      This container would not be suitable for shipment of this waste. Although you are permitted to use a Packing Group I (X-rated) container to ship Packing Group II (Y-rated) hazardous material, exceeding the listed weight limits is not permitted.

      In the case of shipping liquids, the specific gravity rating relates to the weight. Specific gravity is based upon the weight of one gallon of fresh water, or about 8.34 pounds. The container that you are considering (with a specific gravity of 1.4) is only rated/tested to hold something that weighs about 11.7 pounds per gallon. The product you intend to ship (with a specific gravity of 1.9) weighs about 15.8 pounds per gallon.

      A little over four pounds doesn’t sound like much until you multiply that by the number of gallons in the container. For a 55 gallon drum, the difference in weight would be more than 225 pounds. That much extra weight could cause the container to fail in shipment.

      Hope this information helps! If you have any other questions or concerns, feel free to leave another comment.


  • Henrysays:
    03/03/2016 at 3:46 pm Reply

    I am looking for drums to ship PCB-contaminated oil. I have found a company that sells UN-certified 55-gal steel drums but I need to make sure that they are allowed for PCB-contaminated oil. So far, I have been told that the steel drums are coded 1A2/Y. Would these be suitable? If not, what type exactly do I need?

    • Karensays:
      03/03/2016 at 3:48 pm Reply

      Hi Henry,

      The DOT requires anyone shipping hazardous materials (including PCB-contaminated oil) to be properly trained to select appropriate packaging for their shipments. This training teaches you how to choose containers that are compatible with the contents you’re shipping and compliant for hazardous materials shipping.

      In general, from a shipping standpoint, PCB-contaminated oils are not reactive and should not degrade a steel container. If that is the case with your oil, step one in choosing a container is complete.

      The second step is to check the DOT table at 49 CFR 172.101 to find the proper shipping name, packing group and any other shipping restrictions. You mentioned that the container you are considering is marked 1A2/Y. The “Y” tells you that it is rated for hazardous materials in packaging groups II and III. As long as your oil is not a packing group I material, the Y rated container you are looking at may be appropriate if the container is rated for liquids and has a specific gravity rating that is sufficient for the oil.

      The numbers that follow the “Y” in the UN rating will tell you that. If the UN number on your container has an “S” anywhere in it, it is not appropriate for shipping hazardous liquids.

      If the container is rated for liquids, there will be a number following the “Y” that will typically be greater than 0.01 and less than 13.0. This number is a reference to the specific gravity of the liquid that will be shipped. As a reference, water has a specific gravity of 1.0. Most oils have a specific gravity of less than one. If your oil does not exceed the specific gravity listed in the UN marking, it may be appropriate for shipping this material.

      As a hazardous materials shipper, you’ll also need to be aware of the marking, labeling, container closure and manifesting requirements for this shipment. DOT hazmat training also covers these topics.

      Hope this info helps! If you have any other questions or concerns, please leave another comment.


  • Savanna Gascasays:
    05/06/2016 at 6:18 am Reply

    Useful post ! I learned a lot from the information , Does anyone know where I could possibly find a template a form example to use ?

    • Brittanysays:
      05/10/2016 at 1:04 pm Reply

      Hi Savanna,

      Thank you for your comment. Are you inquiring about a template to figure out UN-ratings?


  • SHAWNsays:
    09/14/2016 at 12:34 pm Reply

    If I put a liquid product that is in its origional packaging into a solid rated container is it considered a solid or a liquid?

    • Karensays:
      09/16/2016 at 2:41 pm Reply


      Technically, it is considered a solid. But, remember that doing this may subject you to DOT’s overpacking or lab packing requirements.

      Please leave another comment if you have any additional questions.


  • Keithsays:
    08/14/2017 at 3:42 pm Reply

    Is there a specific pail needed in which to store and ship a corrosive liquid?

    • Karensays:
      08/15/2017 at 6:40 pm Reply

      Hi Keith,

      The quick answer is yes, there is. Chances are good that the container will be plastic – but there is more that you need to know before you can choose the right one.

      Every time a hazardous material (including a corrosive liquid) is offered for shipment, the person offering the material needs to consider the container that will be used for shipping. The U.S. Department of Transportation (DOT) governs the transportation of hazardous materials and requires the “offerer” of any hazardous material that will be shipped by rail, air, motor vehicle or vessel to be trained to choose the appropriate containers for their hazmat shipments [49 CFR 171].

      Part of this training includes learning how to read the Hazardous Materials Table [49 CFR 172.101]. This table lists hazardous materials according to their proper shipping names and provides the shipper with information about the types of containers that are permissible as well as how the container will need to be labeled, marked and prepared for shipment. The table also lists special packaging requirements and provisions that need to be taken when the materials are shipped.

      Following the specifications in the Hazardous Materials Table will ensure that you choose the right type of container for your corrosive liquid, as well as any other hazardous materials that you may need to ship.

      Please let us know if you have any other questions.

      Karen Hamel

  • Aashay Chaukekarsays:
    10/24/2017 at 7:44 am Reply

    Great post. Really helpful content.

  • Nicksays:
    03/10/2018 at 6:10 pm Reply

    I’m trying to figure out what’s inside the drum In my house. It’s got labels but I don’t understand

    • Karensays:
      03/14/2018 at 12:21 pm Reply

      Hi Nick,

      You could begin by taking a picture of all of the labels on the drum and contacting your local hazmat team to see if they can provide any assistance based upon the labels that are on the container. Typically, you can get the contact information from your local emergency management agency. They may also have additional resources for someone who can assist you locally.

      If they are not able to identify the material from the labels on it, hazardous waste disposal companies like Safety Kleen can take a sample of the material in the drum and analyze it to determine what it is. They can also recommend proper disposal methods for it after determining what it is. There will be a cost associated with analyzing the material, and if it is hazardous, an additional cost for proper disposal. Be sure to discuss that before scheduling an appointment.


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