All About Torque

Whether you are using combination or single UN packaging, closing instructions are an essential piece to the puzzle. You can read more about closing instructions in this article.

Not only is the type of closure or inner packaging used important to shipping a compliant UN packaging, but how you tighten the closure can be the difference between your dangerous goods safely arriving to its destination or a dangerous spill. The best way to determine your container is closed properly is the torque value that is applied to the closure.

What is Torque?

Torque is a measure of the tendency of a force to rotate an object around an axis or pivot. In terms of packaging, torque is measured using a device called a torque wrench. A torque wrench is a specialized tool designed to apply a specific amount of torque to a closure. There are different types of torque wrenches, but they generally operate on the same principle of using a calibrated internal mechanism to measure and control the applied torque. Torque is measured in units like feet/pound (ft/lb) or inches/pound (in/lb). If you are closing a single packaging, such as a drum, or an inner bottle in a 4G combination packaging, the torque value applied during the UN testing will be listed in the closing instructions. Essentially, the torque value will tell you how much to tighten a closure on a packaging, and the torque wrench will ensure it is tightened to that specification.

Torque In the Regulations

When you are closing your inner container or single UN packaging, the regulations are very specific in terms of the importance of applying torque to the closures correctly. For example, in the 49CFR 178.602 (e), it says that each packaging must be closed in preparation for testing in the same manner as if prepared for actual shipment, and all closures must be installed using proper techniques and torques (how tight the cap must be placed on the container). This means that however the closure was applied on the packaging in the lab, the same torque must be used when using the packaging to ship dangerous goods. In addition, in TDG 5.1.1 (2) it states that a person must not offer for transport, handle or transport dangerous goods in a standardized means of containment unless the standardized means of containment is in standard. And remaining in standard would include closing the packaging properly in accordance with the closure instructions. The key is, always make sure you check with your packaging manufacturer and look over your closing instructions carefully. And if you are interested in our torque tooling to ensure your packaging meets the required torque requirements, contact us at 888.442.9628 (USA) or 888.977.4834 (Canada) or send us an email.