The Assigned Protection Factor (APF) indicates the level of protection a worker can realistically expect from a respirator when used correctly in the workplace. It reflects the respirator’s ability to reduce the wearer’s exposure to hazardous substances and is based on actual use rather than laboratory conditions.

It is important to note that APF is different from the Nominal Protection Factor (NPF), which is a theoretical value derived from performance under controlled test conditions.

The APF should be used once the Required Protection Factor (RPF) has been established for a specific work environment. This ensures the selected respirator provides sufficient protection. Because APF values can vary between countries, always refer to local legislation or guidelines when choosing respiratory equipment.

Key points:

• APF refers to the realistic protection a respirator offers in the workplace.
• It differs from NPF, which is based on standardised testing.
• APF is used after determining the RPF to choose suitable respiratory protection.
• Protection levels may differ depending on local regulations.
• Always verify the correct APF values according to national guidelines.