Constanzo® K 300 / KB 300 A – Humidity Test Chamber

Constanzo® K 300 and KB 300 A are 300-litre benchtop corrosion test chambers developed to evaluate the resistance of paints and coatings under high-humidity and condensation conditions.

The chambers generate high relative humidity and continuous condensation on the samples by heating the water bath at the bottom of the test chamber. This controlled environment allows moisture-related deterioration in paints, coatings, metals, plastics, and various material systems to be examined.

Constanzo K 300 offers an economical and easy-to-use solution for constant condensation humidity tests, while the KB 300 A enables the automatic application of constant and alternating condensation atmospheres through its automatic ventilation system and programmable controls.

In a condensation humidity test, demineralised water at the bottom of the test chamber is heated. As the water evaporates, it creates conditions of approximately 100% relative humidity within the enclosed test volume.

When the surface temperature of the test samples is lower than the chamber atmosphere, water vapour condenses on the samples. This exposes them to intense humidity under continuous or alternating conditions.

This method is particularly used to examine moisture-related deterioration in:

• Paints and organic coatings,
• Metallic and conversion coatings,
• Automotive components,
• Galvanised surfaces,
• Building and exterior façade components,
• Enclosures for electrical and electronic equipment,
• Plastic and composite components.

After testing, rust formation, blistering, colour change, loss of gloss, coating delamination, loss of adhesion, and other surface changes can be evaluated according to the relevant product standard.

Constanzo K 300 is a 300-litre benchtop condensation humidity test chamber without automatic ventilation.

The chamber operates according to the conventional heated-water-bath principle and is designed particularly for tests requiring a constant condensation humidity atmosphere. The test chamber temperature is regulated by precise PID temperature control.

The K 300 is suitable for:

• Constant condensation humidity tests,
• CH test atmospheres according to TS EN ISO 6270-2,
• Tests that do not require automatic ventilation,
• Routine quality control work,
• 300-litre applications in laboratories with limited space.

Test stages requiring ventilation or a transition to ambient conditions can be managed manually by the operator. If automatic cycles are to be performed regularly, the KB 300 A is the more suitable choice.

Constanzo KB 300 A is a 300-litre condensation humidity test chamber equipped with an automatic ventilation system and touchscreen control panel.

The automatic ventilation system allows ambient air to pass through the test chamber without requiring the operator to open the chamber lid. This enables controlled transitions between the humid condensation stage and ventilation or ambient-atmosphere stages.

The KB 300 A can perform:

• Constant condensation humidity tests,
• Alternating condensation humidity tests,
• Automatic ventilation stages,
• CH, AT, and AHT atmospheres,
• Repeated test cycles.

The test programme is managed through the touchscreen. Temperature changes and test stages can be monitored graphically on the display. With the required options, test data can be exported via USB.

The K 300 offers a simpler solution for laboratories conducting routine quality control tests exclusively under constant condensation conditions.

The KB 300 A is intended for applications requiring automatic ventilation, repeated test cycles, and more comprehensive test monitoring.

TS EN ISO 6270-2 defines methods for exposing coated test samples to constant or alternating condensation-water atmospheres.

The standard specifies three basic atmospheres:

The test chamber remains closed, creating a continuous condensation environment at approximately 100% relative humidity.

The CH atmosphere can be generated using either the K 300 or KB 300 A.

Condensation stages alternate with controlled ventilation and exposure to the ambient atmosphere.

For AHT tests, the KB 300 A with automatic ventilation allows the test stages to be repeated without operator intervention.

Test samples are exposed to different temperature and condensation stages inside the closed test chamber. The applicable temperature changes and cycle durations are determined according to the standard or product specification.

The KB 300 A should be selected for regularly repeated, automatic AT cycles.

For detailed information about Liebisch system codes and other process combinations, please visit the Liebisch Process Systems page.

With the appropriate configuration and required options, Constanzo K/KB 300 can be used for the following test methods:

TS EN ISO 6270-2 – Paints and Varnishes — Determination of Resistance to Humidity — Part 2: Condensation
Specifies the conditions for exposing coated test samples to constant or alternating condensation atmospheres inside a test chamber equipped with a heated water reservoir.

GME 60201
A manufacturer standard used in the automotive industry to evaluate the resistance of components and coatings under condensation humidity conditions.

DIN 50017 – Testing in Condensation Water Atmospheres
A German standard historically widely used for condensation humidity testing. Today, most of these methods are covered by DIN EN ISO 6270-2.

Condensation Tests with SO₂ Gas
With a suitable configuration and gas dosing accessory, the Constanzo chamber family can also be used for corrosion tests conducted in a humid sulfur dioxide atmosphere.

ISO 22479 – Sulfur Dioxide Test in a Humid Atmosphere
ISO 22479 is the current international test method for evaluating the resistance of metals, metal alloys, metallic and non-metallic coatings, and organic coatings in a humid atmosphere containing sulfur dioxide. This standard replaced the former ISO 3231 and ISO 6988 methods.

Former Standard Designations

The following standards may still appear in older specifications and technical documents:

• DIN 50018
• TS EN ISO 3231
• TS EN ISO 6988

ISO 3231 and ISO 6988 have been withdrawn. ISO 22479 should be used as the current reference for new projects and specifications. If testing according to a former standard is requested, the method and customer requirements should be verified separately.

Gasomat is a manual dosing system used to introduce the required quantity of SO₂ gas into the test chamber in a controlled manner during condensation tests involving SO₂. The system measures a defined volume of gas using the displacement-liquid principle and allows the operator to transfer it into the test chamber.

In these applications, a controlled quantity of SO₂ gas is introduced into the test chamber. The gas combines with condensed water to create a more aggressive corrosive environment. This test method is commonly known as the Kesternich test.

SO₂ gas testing is not a standard function of the basic K 300 or KB 300 A chamber. Suitable gas connections, safety equipment, the Gasomat dosing system, and laboratory ventilation must be evaluated together.

Two dosing ranges are available:

• Gasomat 200 – suitable for a gas volume of 200 ml
• Gasomat 2000 – suitable for gas volumes of 1000 or 2000 ml

The required gas quantity should be determined according to the applicable standard and test chamber volume.

SO₂ is a toxic and corrosive gas. The gas cylinder, connections, exhaust line, laboratory ventilation, and operator safety measures must be planned in accordance with the applicable regulations and manufacturer’s instructions.

For applications requiring automatic gas dosing and more advanced safety features, automatic Kesternich test systems should be considered.

Constanzo chambers feature a conventional water bath at the bottom, into which a specified quantity of demineralised water is introduced. At the beginning of the test, the demineralised water is added to the bottom of the test chamber and the samples are positioned inside. The lid is then closed to isolate the test volume from the external environment, and the water bath is heated to the specified temperature.

As the water heats and evaporates, it creates high relative humidity inside the chamber. The resulting water vapour condenses on the cooler sample surfaces. The test temperature and duration are maintained according to the relevant standard; models with the required features can also perform ventilation and ambient-atmosphere stages.

To ensure comparable test results, water quality, sample positioning, test temperature, test duration, and cycle stages must be maintained in accordance with the relevant standard.

Constanzo K 300 and KB 300 A can be configured with the following options:

The options should be evaluated together with the applicable test standard, required operating temperature, cycle stages, and laboratory infrastructure.

If you will only perform constant condensation humidity tests, manage the test stages manually, and require an economical benchtop solution, the Constanzo K 300 may be suitable.

If automatic ventilation, repeated cycles, touchscreen control, and more comprehensive test monitoring are required, the Constanzo KB 300 A should be selected.

Share your intended test standard, test cycle, sample dimensions, and required capacity with us so we can assess the necessary process systems and a suitable chamber configuration together.

Contact us for assistance with selecting the appropriate Liebisch process system and chamber, and for a technical quotation.