What is Primary Retention

What Is Primary Retention?

Primary retention is the main method used to hold an object, component or piece of equipment securely in its intended position during normal operation.

In simple terms:

Primary retention is what is designed to keep an object attached in the first place.

It is the first line of defence against an object becoming detached, moving unexpectedly or falling.

Examples of primary retention

Depending on the equipment and application, primary retention can include:

• Bolts and nuts
• Screws
• Mounting brackets
• Clamps
• Mechanical fasteners
• Welded connections
• Threaded fixings
• Manufacturer-designed mounting systems
• Structural attachment systems

For example, a light fitting installed on an offshore structure may be secured using a manufacturer-specified bracket and mechanical fixings. These form the primary retention system.

Primary retention vs secondary retention

The distinction is important for DROPS prevention.

Primary retention
The main system designed to secure the object during normal use.

Secondary retention
An additional, independent system intended to help prevent the object from falling if the primary retention system fails.

For example:

Primary:
Light → mounting bracket → bolts → structure

Secondary:
Light → retention wire → structure

The secondary system should not be considered a substitute for properly designed, installed and maintained primary retention.

Why can primary retention fail?

Even a correctly installed primary fixing can potentially be affected by:

• Vibration
• Corrosion
• Fatigue
• Mechanical impact
• Wear and deterioration
• Incorrect installation
• Loose or damaged fixings
• Environmental conditions
• Equipment modification

This is why dropped-object prevention may require additional controls, including secondary retention, where the risk assessment and applicable requirements identify the need.

Primary retention in working-at-height environments

Primary retention is particularly important for equipment installed or used above people.

Examples include:

• Lighting
• Cameras
• Instrumentation
• Electrical equipment
• Signs
• Covers and panels
• Brackets
• Valves and components
• Maintenance equipment

For portable tools being handled by workers, tool tethering provides a different form of dropped-object control.