FEA 643: Measurement of Discharge Rate for Filled Aerosol Packs

Standard Overview

FEA 643 is an industry standard issued by the European Aerosol Federation (FEA) that defines a reproducible test method for measuring the discharge rate of filled aerosol packs.

The discharge rate is expressed in grams per second (g/s) and represents the quantity of product expelled through the valve during a defined discharge time under controlled conditions.

Scope and Limitations

This method is applicable to the majority of aerosols currently on the market, including cosmetic, household, and technical products.

However, the standard explicitly excludes:

• Metered-dose valves
• Inverted use of vapour phase tap valves

Test Principle

The discharge rate is determined by:

1. Weighing the aerosol pack before discharge
2. Operating the valve for a defined time interval
3. Weighing the pack again

The mass difference divided by the discharge time gives the discharge rate in grams per second.

Required Apparatus

• Water bath maintained at 25 ± 0.5 °C
• Stopwatch accurate to 0.2 s
• Balance readable to 0.1 g
• Pressure gauge accurate to 0.5 bar

Test Sample Preparation

Aerosol samples may be:

• Randomly selected from production after hot water bath testing
• Carefully prepared experimental batches

All defective samples must be rejected, including:

• Leaking packs
• Misaligned valves
• Blocked or malfunctioning valves

Conditioning and Pre-Spray

Before measurement:

1. The aerosol is operated for 5 seconds to clear the dip tube
2. The pack is conditioned in a water bath at 25 °C for at least 30 minutes

This ensures temperature equilibrium and homogeneous product composition.

Discharge Test Procedure

1. Remove the pack from the water bath and wipe dry
2. Operate the valve for 1 second to remove residual water
3. Measure internal pressure
4. Weigh the pack (±0.1 g)
5. Shake the pack for 3 seconds
6. Discharge continuously for 10 seconds
7. Reweigh the pack

The procedure is repeated three times unless otherwise justified.

Calculation Method

Discharge rate is calculated as:

Discharge rate (g/s) = (Mass before − Mass after) ÷ Discharge time

Individual results should not differ by more than 0.1 g from the mean of the determinations.

Alternative Life-Cycle Measurement

For systems where discharge behaviour changes during emptying, measurements may be performed at different fill levels:

• 90%
• 70%
• 50%
• 30%
• 10%

Results may then be plotted to visualise discharge evolution over pack life.

Reporting Requirements

Test reports shall include:

• Measured discharge rate (g/s)
• Mean internal pressure
• Discharge method used (e.g. 3 × 10 s)
• Container specification
• Valve and orifice details
• Initial fill level

Engineering Significance

FEA 643 is essential for:

• Spray performance comparison
• Valve and actuator optimisation
• Stability testing and ageing studies

It is commonly used together with:

• FEA 606 – hot water bath testing
• FEA 621 – container pressure resistance
• FEA 623 – filled pack mechanical resistance

FAQ – Engineering & QA