Container seals are integral components of shipping containers that help protect the container and its shipments against tamper, theft and mishandling. Different types of seals can be used on containers according to the security requirement of the shipment. Customs authorises the container locks and ensures the cargo is of the right quality and quantity when loading and unloading. The container seal number helps approve that the correct container has reached its destination and is listed as a part of the bill of lading. Let us learn more about container seals and their importance.

What is a container seal?

A seal is a device that fastens or holds together two things to prevent the inside contents from breaking through. Seals are fixated on container doors in shipping containers as locks to preserve the cargo. Seals are essential parts of shipping containers during national and international shipping. It can also be described as a ‘one-time door lock that acts as an authoritative lock that helps avoid unauthorised access. A container seal cannot be removed repeatedly and needs to be cut open to enter the container. Customs officials check and seal all shipping containers before being sent off for transportation. Upon arrival, container seals are inspected and then removed carefully.

What is a container seal number?

Each container seal is marked with a series of alphabets and letters on the base and pin of the seal. The container seal manufacturer or the shipping lines mark these numbers. Container seal numbers are allotted to facilitate legal cross-border trade under the CBP guidelines so that the container seamlessly passes all customs inspections. The container seal number for FCL shipping can be acquired regularly by the shipping line. Whereas for LCL shipments, the freight forwarders note the container seal number and convey it to the shipping carrier.

Why do you need a container seal?

Container seals are essential parts of shipping containers that help extend security to the shipment inside cargo containers. The importance of container seals is as follows-

1. Ensure shipment loading– During cargo loading, there are chances of cargo damage, tampering, or loss during cargo handling. A customs official supervises the container loading process and seals the container after loading it. A sealed container is a surety that the cargo has been carefully stuffed inside the boxes according to the goods listed in the bill of lading.
2. Secure container contents– A significant portion of cross-border trade is carried through shipping containers loaded onto various modes of transport. During their transit, chances of theft and tampering are high. Intact container seals validate that the containers have not been mishandled.
3. Ensure proper closure of doors– During the intermodal transportation of shipping containers, improperly locked container doors may open due to pressure and turbulence during shipping. A properly sealed container ensures that the container door will remain shut and the shipment will not gush out of the container.
4. Part of bill of lading– Container seal numbers are mentioned in the bill of lading and are checked by the customs to ensure that the proper shipment has arrived through international import.

What are the different types of container seals?

The different types of container seals are as follows-

1. Cable seals– These are high-security seals for shipping containers that can only be cut using cable cutters. The cable length can be adjusted, and the diameter of the cable can be chosen based on the requirement. They are durable and designed to provide high resistance to secure international shipments. They are heat resistant and comply with C-TPAT standards of international shipping.
2. Bolt seals– It is an intrusion-resistant container lock made up of metal and metal wires that comply with the standards for ISO container seals. They are robust and resilient to any kind of tampering.
3. E-seals– RFIDs are electronic seals with RFID tags or readers embedded in container door seals. The radio frequency reads the data transmitted by RFID readers and provides premium security to shipping containers.

How to fix container seals?

Every container uses at least one container security seal while locking the container. Every container door has two lock rods with locks attached to every rod. So, it makes four door locks combined on both container doors. Out of both the doors, the right door is opened first, so it is prevalent that shippers put a seal on one or both locks of the correct container door. Seals can also be put on the left door for extra security. An optional place for fixing a seal is to secure a cam on the third locking bar near the bottom of the container. 

• Container seal locks are issued by the shipping lines carrying the container.
• The cargo loading into shipping containers is supervised to ensure all the goods are rightfully loaded following ISO guidelines.
• The left door is closed and sealed, followed by the right container door.
• The pin and base of the seal must be removed before putting the seal.
• The shipping container seal is then carefully placed, usually on the right container door lock, into the bolt space between the handle and the retainer catch.
• After placing the seal into the bolt space, press the pin and base of the seal against each other. A clicking sound indicates that the seal is locked.
• Following the container seal inspection, note that the pin and base numbers are identical and list them in the bill of lading.

How to remove container seals?

• The consignee assists the removal of container seals when the shipping container reaches its final destination through intermodal transport. 
• If the containers are brought to the destination using trucks, a small stool or ladder is generally used to reach the container seal. 
• Using bolt cutters or pliers, the seal is cut along its length. 
• After cutting through, the seals are rightfully removed before the consignee.

What are the customs requirements for container seals?

1. Follows ISO 17712 standard– The ISO standard sets the requirements to manufacture high-security seals and emphasises seals’ design, strengths and tamper-proof features to prevent counterfeiting and facilitate international shipping.
2. Tamper-evident seals– To prevent tampering, seals are given serial number markings for one-time use only. In case of any tampering, the seal breaks.
3. Unique seal numbers– Every container seal is marked with a unique serial number on the base and pin either by the manufacturer or the shipping line. 
4. Authorised suppliers– Container seals must be purchased from authorised suppliers to ensure compliance with the standard. It helps in securing authentic container seals.
5. Documentation– The shipping documents must enlist the container seal number and the type of container seal so that the shipment can be easily verified to check the integrity of the shipping container and the cargo inside.

What happens if a container seal is broken?

If, upon reaching the destination, the container seal is found to be broken, it signifies that the cargo inside the container has been tampered with. The consignee must immediately notify the shipping carrier and the insurance company. Both these authorities then surveyed to ensure that the container seal was broken upon the delivery of the shipment. If the survey confirms that the container seal has been tampered with, a formal claim can be raised with the insurance party.

The information about container seals will help you gain more knowledge about the importance, benefits, and fixing of container seals.

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