A Box Maker’s Certificate, also known as BMC, is a small circular stamp on the outer flap of the box, which identifies its manufacturer, contains the specifications of the box, and serves as a mark of compliance. The box maker’s certificate also mentions how much stress a box can bear, based on the amount of material used.
The following section explains what each component of the BMC conveys.
The BMC contains the manufacturer’s name and location, which includes the state name, country name, and the zip or postal code. It is located on the external circumference of the stamp.
Number of Walls
Below the manufacturer’s name, contains the number of walls. It is simply the number of corrugated boards that are used in making the box. It is generally written as “single wall”, “double wall”, and “triple wall”. The higher the number of boards used, the stronger the walls of the boxes get. But, increasing the number of boards leads to making heavier boxes.
Strength of the Box
The strength of the box is generally denoted as the maximum force that can be applied to the box before it gets crushed or is punctured. Manufacturers either use the Edge Crush Test or the Mullen Bursting Test to measure the strength of the corrugated board.
The Edge Crush Test, also known as ECT shows how much force the edge of the corrugated board can take before it gets crushed. It is expressed as lbs/in, that is, force per unit length in the imperial system. A standard corrugated board comes with 32 lbs/in rating.
The Bursting test measures how much internal or external pressure the box can withstand before it is impaled. It is also called the Mullen Bursting Test since it is tested using a Mullen Tester. The Bursting test results are given in lbs/square inch, the unit, force per unit area or pressure in the imperial system. The 200 lbs/square inch rated corrugated boards are slightly stronger than ones with 32 ECT corrugated boards.
Weight and Size Limits
Finally, the BMC defines the weight and size limit of the box. The size limit specifies the maximum external dimension of the corrugated board and the weight limit states the maximum weight tolerance of the box. This information helps in understanding the limitations of the box and helps you pick the right box for shipping.
Information that BMC Does Not Contain
The BMC is a little debated since all the information on the certificate does not suffice the information needed for practical real-world shipping requirements.
The BMC does not contain any information about moisture resistance of the box. Neither does it say how well the box can survive drops. Both of these are quite important for shipping the products in corrugated boxes.
What the BMC says is that the box holds up to a certain standard. But there are many other high-quality boxes that do not come with a certificate.
Given the practical requirements, where shipping to a distant place might require days and unprecedented environmental conditions, the box maker’s certificate might not be the most reliable choice for the safety of your product. It is recommended to test the box yourself for the durability before placing your order.
[Image courtesy: aiccbox.org]1