FEA 606: Water Bath Testing of Filled Aerosol Packs

FEA 606 water bath testing of filled aerosol packs on production line

Standard Overview

FEA 606 is an industry test method issued by the European Aerosol Federation (FEA) that defines how filled aerosol packs are verified for compliance with legal pressure requirements using a hot water bath test.

The method supports the requirements of Directive 75/324/EEC, which mandates that every filled aerosol dispenser must undergo a final test ensuring it can safely withstand the internal pressure generated at an equivalent temperature of 50 °C.

Key insight: FEA 606 does not define acceptance pressure limits—it verifies that the production process achieves the required pressure conditions.

Position in the Regulatory Framework

The Directive allows three alternative final test methods:

  • Hot water bath test
  • Hot final test methods
  • Cold final test methods

FEA 606 specifically addresses the hot water bath approach and provides a checking procedure to confirm that the bath conditions actually cause the aerosol to reach its equilibrium pressure at 50 °C.

Purpose of the Method

Because the speed at which internal pressure rises depends on several variables—such as formulation, container size, propellant type, and bath design— it is not sufficient to rely on nominal bath temperature alone.

FEA 606 therefore establishes a method to:

  • Determine the true equilibrium pressure at 50 °C
  • Verify that production-line bath conditions achieve this pressure
  • Adjust bath temperature or dwell time if necessary
Engineering reality: A bath set to 50 °C does not automatically guarantee a can reaches its 50 °C pressure.

Scope of Application

The method may be applied to:

  • All types of aerosol dispensers
  • Any production line equipped with a water bath
  • Both continuous and batch-based bath systems

Apparatus

  • Pressure gauge with resolution of 0.1 bar
  • Water bath maintained at a nominal minimum of 50 °C
  • Conveyor system or immersion device providing controlled dwell time
Safety note: Operators must wear approved eye protection and gloves when handling samples from the bath.

Test Principle

The method compares:

  • The equilibrium pressure at 50 °C, determined under controlled laboratory conditions, and
  • The actual internal pressure of production samples immediately after exiting the water bath

If the production samples reach at least the equilibrium pressure, the bath conditions are considered compliant.

Test Procedure – Engineering Interpretation

1
Prepare components

Select, mark, and weigh nine empty containers and valves.

2
Fill production samples

Fill nine samples on the production line, checking component weights at each filling stage.

3
Check purging efficiency

Verify purging efficiency by measuring equilibrium pressure at 25 °C on three samples according to FEA 604.

4
Determine 50 °C equilibrium pressure

Determine the equilibrium pressure at 50 °C on another three samples using FEA 604.

5
Stabilize water bath conditions

Stabilize the water bath and conveyor until thermal equilibrium is reached.

6
Run bath verification samples

Pass the remaining three filled samples through the water bath.

7
Measure pressure at exit

Immediately measure internal pressure at bath exit without shaking the containers.

8
Decision check

Compare measured pressure with the equilibrium pressure at 50 °C.

If PASS

Bath settings are validated. Record temperature, dwell time, water level, and circulation conditions.

If FAIL

Increase bath temperature or increase dwell time (reduce conveyor speed), then repeat verification with new samples.

Critical rule: Any shaking or mixing of the container will reduce measured pressure and invalidate the result.

Adjustment of Bath Conditions

If any measured pressure is lower than the equilibrium pressure:

  • Increase the bath temperature, or
  • Reduce conveyor speed to increase dwell time

The test must then be repeated with new samples until measured pressures meet or exceed the equilibrium value.

Recording and Reporting

Once compliant conditions are achieved, the following must be recorded:

  • Bath temperature
  • Water level
  • Water circulation rate
  • Container dwell time or conveyor speed

The test report should also include:

  • Formulation description
  • Packaging specification
  • Fill level

Important Technical Notes

  • Bath conditions must be checked at regular intervals.
  • Any change in product or container size requires revalidation.
  • Compressed gas systems may require additional evaluation.
  • Products forming stable foam may show slower pressure rise.
Process insight: Small increases in bath temperature can significantly reduce required dwell time.

Relationship with Other Standards

  • FEA 604 – Determination of equilibrium pressure
  • FEA 605 – Density measurement of aerosol formulations
  • Directive 75/324/EEC – Aerosol Dispensers Directive
Download the Standard PDF

This document provides FEA 606, defining a water bath test method to verify conformity of filled aerosol packs with Directive 75/324/EEC. It establishes pressure comparison procedures at 50°C to ensure production lines achieve required equilibrium pressure conditions.

FAQ – Engineering & Compliance

Yes, unless an alternative approved hot or cold final test method is used. FEA 606 supports compliance with European legislation.

Shaking lowers liquid temperature and gas-phase pressure. Even slight agitation can produce falsely low readings.

Not necessarily. The can must reach the pressure equivalent of 50 °C, which depends on dwell time and heat transfer.

At regular intervals and after any change in formulation, container size, or line configuration.

Yes. The method can be adapted to batch immersion, provided agitation is avoided and conditions are well controlled.

Kelvin Master's Degree Metal Packaging Specialist
Hi, I’m Kelvin

I hold a Master’s degree and have 13+ years of experience in metal packaging, specializing in aerosol cans, aluminum bottles, product development, manufacturing, and sustainability. On Shining Packaging, I share practical insights to help engineers and buyers improve sealing stability.

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