Select Page


AECTP Method 308 Mould Growth Compliance Testing

AECTP Method 308 mould growth compliance testing assesses a material’s ability to support mould growth. AECTP 308 also evaluates how mould growth can affect the performance or use of the material. As a leader in environmental climatic regulatory compliance testing, Keystone Compliance assists manufacturers with AECTP 300 testing. Meeting the AECTP mould growth testing requirements can be challenging. Not only do we understand the challenges, but we help guide companies through the process. 

Keystone takes pride in providing the peace of mind that all of your unintentional radiator testing needs will be met. What sets us apart from other NRTLs is our extensive troubleshooting process. When products do not meet your specified test requirements, we assist in finding solutions.

Request a quote to receive expert testing services tailored to your specific needs. Ready to get started? We are. Contact us to see why so many companies work with us to achieve their climatic testing needs. 

Summary of AECTP 300 Environmental Climatic Compliance Testing

The AECTP 300 standard is intended to be used in conjunction with four other AECTP test standards (AECTP 100, 200, 400, and 500). Furthermore, the AECTP standard provides advice for preparing environmental test specifications, plans, and procedures.

AECTP 300 evaluates climatic environments. These environments can occur individually or in combination with other climatic or mechanical environments.

The AECTP 300 tests outlined provide exposure to simulated conditions from which a degree of confidence can be established. 

During testing, the configuration used for the selected test should be the configuration used within the unit’s life cycle. As a minimum, the following is considered: 

  • In the shipping/storage container or transit case.
  • Protected or unprotected.
  • In its normal operating and thermal configuration.
  • Modified with kits for special applications.

Any of the following will be classified as a failure:

  • A deviation of monitored functional parameter levels beyond acceptable limits.
  • Nonfulfillment of safety requirements or the development of safety hazards.
  • Nonfulfillment of specific test item requirements.
  • Changes to the test item that could prevent it from meeting its intended service life or maintenance requirements.

Scope of AECTP 308 Mould Growth Compliance Testing

Mould growth compliance testing assesses a material’s ability to support fungus growth. Additionally, this AECTP test standard evaluates how fungus growth can affect the performance or use of the material.

Please note that AECTP refers to the term “mould” throughout the entire document. This term is synonymous with “fungus” and/or “Mold”.

The primary objectives of the AECTP 308 mould growth standard are to determine:

  • If the materials or assembled combination of materials will support mould growth. If so, what species?
  • How rapidly molds will grow on the material.
  • How fungus growth affects the material, its mission, and its safety for use after growth.
  • If the material can be stored effectively in a field environment.
  • If there are simple reversal processes. E.g. wiping off mold growth.

This test method is designed to obtain data on the susceptibility of material. AECTP 308 should not be used for the test of basic materials since various test procedures are applicable.

Mould growth impairs the functioning or use of equipment by changing its physical properties. The effects of mold growth are as follows.

Direct Attack on Materials

Nonresistant materials are susceptible to a direct attack as the fungus breaks down materials and uses them as nutrients. This results in the deterioration affecting the physical properties of a material. Examples include:

  • Natural Materials
    • Cellulosic materials
    • Animal-based and vegetable-based adhesives
    • Grease, oils, and other hydrocarbons
    • Leather
  • Synthetic materials
    • PVC formulations
    • Certain polymers
    • Plastics that contain organic laminating materials or fillers
    • Paints and varnishes that contain susceptible constituents

Indirect Attack on Materials

Indirect attacks result from growth on surface deposits of dust, grease, perspiration, and contaminants that causes damage to the underlying material. Damage to mold-resistant materials result from indirect attacks.

This occurs when metabolic waste products excreted by mold cause corrosion of metals, etching glass, or staining or degrading of plastics and other materials.

Physical Interference

Damage to electrical systems may result from either a direct or indirect attack. Fungus growth can form unwanted electrical conducting paths across insulating materials.

Health and Aesthetic Factors

Mould growth on a material can cause physiological problems such as allergies. Additionally, mold growth can be so aesthetically unpleasant that users will be reluctant to use the material.

AECTP 308 Mould Growth Compliance Testing Procedures

It is crucial that specified temperature and humidity are maintained for microbial growth. 

Two groups of molds are commonly used for AECTP 308 fungus growth testing. These organisms were selected because of their ability to degrade material, their worldwide distribution, and their stability.


A new test item is preferable to use. If cleaning is required, it is conducted 72 hours before the start of the test.

AECTP 308 recommends 28 days as the minimum test period to allow for mould germination.

Water used for generating humidity for this test must be free from contaminants.

Next, the test item is inoculated by spraying the solution on the control and test items. The incubation period is immediately following inoculation.

After 7 days, the growth is inspected on cotton strips. If the strips show satisfactory fungus growth, the test is continued for the required period of time. On the other hand, if there is no increase in fungus growth on the cotton strips, as compared to the 7-day results, the test is invalid.

At the end of the incubation period, the test item is inspected immediately.

Lastly, in addition to general information, the following data is provided in the evaluation of the test results:

  • Any mold growth on the test item must be analyzed. This will determine if the growth is on the test item material(s) or on contaminants.
  • Any fungus growth on the test item, whether from inoculum or other sources, is evaluated for the following.
    • The extent of growth on susceptible components or materials
    • The immediate effect that the growth has on the physical characteristics of the material.
    • The long-range effect that the growth could have on the material.
    • The specific nutrients supporting the growth.

Expert AECTP 308 Fungus Growth Compliance Testing Facility

Keystone has a full lab of test equipment which permits us to provide short lead times on scheduling. Our team strives to give our customers more time and energy on product development instead of testing.

Request a quote to find out for yourself about the Keystone difference. For more information on why so many companies partner with Keystone Compliance, contact us

For more information on AECTP 300 testing, please follow the links below: