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Bulk bags are effective packaging solutions for large quantities of materials, including hazardous waste and dangerous goods. These materials need to be clearly marked and labelled on the bulk bag fabric so that every person who interacts with the bag knows what’s inside and what safety precautions to take when handling the bulk bags.

Every bulk bag that is used to store hazardous substances must be clearly marked with UN-approved symbols and information. Custom Bulk Bags is a leading manufacturer and supplier of bulk bags in South Africa, offering high-quality, UN-certified bulk bags to various customers.

We produce up to 3.5 million bulk bags per year; all of which have a minimum safety factor rating of 5:1 and are manufactured in accordance with international regulations and standards. Our bulk bags are suitable for storing and transporting hazardous substances and chemicals.

Employees at Custom Bulk Bags sewing bulk bags on the factory floor

What markings need to be visible?

The following markings and information need to be clearly printed on a UN-certified bulk bag intended for dangerous materials:

  1. The UN packaging symbol.
  2. A designator code for the type of bulk bag (e.g. uncoated with no liner).
  3. A capital letter denoting the packaging group for which the design has been approved (i.e. X, Y or Z)
  4. The last two digits of the month and year of manufacture.
  5. The State authorising the allocation of the mark (e.g. ZA)
  6. The name or logo of the manufacturer.
  7. The stacking test load in kilograms.
  8. The maximum permissible gross mass in kilograms.

These markings need to be durable and legible so that they do not rub off during transit. All letters and numbers must be at least 12mm high. If you order UN-certified bulk bags for dangerous materials, ensure that your supplier has printed these markings in a readily visible place on the fabric.

Custom printing on bulk bags

Stacking markings on bulk bags

In addition to the above markings, bulk bags that are designed to be stacked need to have stacking markings too. These include the minimum dimensions of the width and height of the bags, as well as the maximum load that can be placed on top of the bag in kilograms. 

Those bulk bags that are not designed for stacking must have a symbol (an empty white square with a cross through it on top of a solid black square) to show that no weight can be placed on top. These symbols must all be at least 10cm wide and 10cm tall.

Where dimensions are not specified, the symbols must be in approximate proportion to the actual bulk bags. Depending on the products being stored and transported, additional labels or placards may be required. Speak to your bulk bag manufacturer or supplier to ensure that the correct markings are displayed.

Our team will happily walk you through the ordering and specification process to ensure that you receive the correct design and packaging products for your needs. If you have any questions or need an explanation for certain elements of the bulk bags, our consultants are on-hand to help where possible. For more information about our bulk bags, please contact us today.


Custom Bulk Bags is a leading South African manufacturer of woven polypropylene bags for various industries, such as mining, chemicals and food. We are able to produce over 3.5-million bulk bags per year, keeping our customers in stock at all times. Our bags adhere to the highest levels of quality as a result of our stringent in-house testing and quality control programmes.

Custom Bulk Bags holds ISO 9001 certification and we currently have a number of UN-certified designs. We are a Level 2 B-BBEE manufacturer and supplier and fall under the ownership structure of Deneb Investments Limited. For more information on our products, contact Follow us on Facebook for our latest news and industry insights.