Tamper evident seals. The complete guide

What is a tamper evident seal? What is its purpose? What types of tamper evident seals are there? You will find answers to these questions and more in this blogpost.

Container bolt seal

What is a tamper evident seal?

A tamper evident seal is a device or mechanism that is applied to an object to protect against tampering or unauthorized access. These seals are used on an object to show if the contents have been opened or altered in any way. If a sealed object is opened or infringed the tamper evident seal will demonstrate a clear proof of tampering. For instance, if a container seal is broken, the recipient knows that the container has been tampered with.

Tamper evident seals can come in many forms ranging from security tape to bolt seals. The applications of tamper evident seals are diverse ranging from products at the supermarket, envelopes, containers and entire houses.

Tamper evident seals are also called tamper proof seals, security seals or simply seals.

Classes of tamper evident seals

The International Organization for Standardization (ISO) classifies 3 types of security seals in the ISO 17712 standards.

  • Class ‘I’ indicative seals. Indicative seals have a low breaking strength and can be easily removed by hand.
  • Class ‘S’ security seals. These have a higher breaking strength and can be removed by simple tools.
  • Class ‘H’ high security seals. High security seals have the highest breaking strength and add a layer of protection to the sealed object. Class ‘H’ security seals can only be removed by special tools such as bolt seal cutters. Because of their high breaking strength, high security seals are often required for international freight transport.

You can read more about this subject in our article about ISO 17712.

Types of tamper evident seals

The most popular types of tamper evident seals are security tape, plastic seals, cable seals and bolt seals.

Security tape & labels

Security tape and labels

These security seals are stuck on an object. If the sealed object has been infringed, the security label will show clear visible evidence of tampering. Often it shows a message such as VOID / OPEN. Security tape can be broken easily and is therefore used for indicative use.

Plastic seals

Plastic Seal DS-F 400 Yellow by Hoefon Security Seals

Plastic security seals are flexible seals that are locked to an object. Plastic seals can often be removed by hand and are a cost effective solution for tampering products. Plastic seals are used for indicative purposes.

Cable seals

Aluminium Cable Seal CA-5.0A

Cable security seals consist of a metal cable and a locking device. These seals are versatile and have usually a higher breaking strength than plastic seals. Cable seals are often class ‘S’ of class ‘H’ ISO 17712:2013 certified.

Bolt seals

Bolt Seal BS40 Yellow by Hoefon Security Seals

These seals consist of a pin and barrel. Bolt seals are often class ‘H’ ISO 17712: 2013 certified and used for international container transport. Because of their high breaking strength they offer a strong layer of security to transports.

Application tamper evident seals

Tamper evident seals are also often named after their application. Therefore, the following designations among others are also used to name tamper evident seals.

  • Container seals
  • Cargo seals
  • Truck seals
  • Trailer seals
  • Airline seals
  • Pharmaceutical seals
  • Fire extinguisher seals
  • Utility meter seals
  • Tachograph seals

The seals used for the above applications are most often plastic seals, cable seals or bolt seals. For instance, bolt seals and cable seals can be used as container seals. Plastic security seals are generally used to seal fire extinguishers. You can find more information about which seals are suitable for which application on our page security seals applications.

How to determine which tamper evident seal is suitable

The purpose of the tamper evident seals determines which type of seals is most suited. If you want to use a seal solely to indicate unwanted infringement a plastic seal or security tape is probably your best choice. If you want to add a layer of security to a sealed object, we recommend a security seal with a high breaking strength.

Laws and regulations can also impact the choice of suitable tamper evident seals. International freight transports often demands the use of ISO 17712 certified high security seals. The Customs Trade Partnership Against Terrorism (CTPAT) also dictates that a high security seal must be affixed to all loaded containers bound to the United States.

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About Hoefon Security Seals

Hoefon Security Seals is a ISO 9001 certified supplier of various types of tamper evident seals. We are CTPAT compliant and product ISO 17712:2013 certified high security bolt seals and cable seals. We offer competitive prices and we ship globally. Please view our complete range of security seals.

We are also an expert in designing and manufacturing custom security seals. Whether it is a different color, adjusted cable length, or completely new product, our engineering team listens carefully to your wishes. You can find more information about custom solutions on our page custom security seals.

Robert Senders

Robert senders

Sales engineer Hoefon Security Seals

Robert Senders has been Hoefon Security Seals’ sales engineer since 2014. He has extensive experience in designing and developing various types of security seals.

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