Fortress Key Engravings
Trapped Key Systems are advanced safety devices commonly used in manufacturing plants refineries and other industrial facilities. They work by interlocking keys, ensuring safety measures are followed in sequence.
The effectiveness of these systems relies heavily on the design and management of keys, which are essential for controlling access and preventing accidents. Fortress Safety provides detailed guidelines on key engravings.
Fortress maintains records of engravings and key codes (differ) following the guidelines of ISO/TS 19837: 2018. This standard emphasizes the necessity for all Trapped Key Systems to have measures in place to prevent unintentional duplication of key codes. It stresses that codes must not be duplicated unintentionally, ensuring the integrity and safety of the system.
Key Guidelines for Engravings
1. Engraving Requirements
All keys must have an engraving for identification purposes. This engraving is supplied by the customer and must be in capital letters. The maximum length is 30 characters, divided into three lines of up to 10 characters each. For example, “MACHINE A/AREA B/WELDING” would be engraved as:
• 1st line: MACHINE A
• 2nd line: AREA B
• 3rd line: WELDING
The engraving is visibly displayed on the front of keys, locks, and dust covers.

Are you wondering how to best define the engraving on your keys for optimal clarity and functionality? Here’s a simple guide to help you determine what information to include on each key.
Line 1. Location
Use the first 10 characters to summarize the device’s location. For example, “PRODUCTION” for a machine in the production area.
Line 2. Machine Description
Use the second line of 10 characters to describe the machine itself. For instance, “ROBOT CELL” for a specific machine type.
Line 3. Key Function
On the third line, define the operation of the key. Choose descriptive terms such as “ISOLATION” for isolating machinery, “ACCESS” for granting entry to secured areas, or “SAFETY” for safeguarding operators in a specific zone.
2. Key codes (Differ codes)
Each key is also assigned a unique key number. The Key Number (also referred to as “differ”) consists out of seven digits and is produced and documented by Fortress. Once an order is placed, key numbers are assigned to the provided engraving. These key numbers correspond to the specific cuts on a key, determining its compatibility with a particular lock.

3. Compliance with Standards
Fortress adheres to ISO/TS 19837: 2018 standards, which emphasize the prevention of unintentional duplication of key codes. This standard requires manufacturers to maintain a register of key codes to ensure the integrity and safety of their trapped key systems.
4. Required Information for Key Codes
When placing an order that includes keys, customers need to provide the following details:
• End User Organisation Name
• End User Address
• Engraving details
5. Reordering and Modifying Keys
For reorders or modifications, customers must provide exact details, as once an engraving is assigned to a key number, it cannot be changed. This ensures consistency and security in key management.
6. Supply of Duplicate Keys
Duplicate keys are only supplied for the replacement of lost or damaged keys. If spare or master keys are used, they must be under strict management control and included in the risk assessment.
These guidelines help maintain the safety and functionality of the Fortress safety systems by ensuring that key codes are unique and traceable.
Common Fortress Keys Part Numbers
CLK-SUSS
Standard Differ Stainless Steel Key with Grey Seal
-Compatible with all standard CL-type locks
CLK-SUCS
Standard Differ Stainless Steel Key with Coloured Seal
-Compatible with all standard CL-type locks
CLK-LP-SU
Standard Differ Low-Profile Stainless Steel Key
-Compatible with all standard CL-type locks
MLK-SUGS
Standard Differ Stainless Steel Key with Gold Seal for Master-able Locks
-Compatible with ML-type locks
MLK-SUCS-…
Standard Differ Stainless Steel Key with Coloured Seal for Master-able Locks
– Compatible with ML-type locks
MLK-SUGM
Mastered Stainless Steel Key with Gold Seal with Master Series.




