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AECTP Shock TestingAECTP Method 304 Thermal Shock Testing

AECTP 300 Method 304 thermal shock evaluates the effects of quick changes in temperature on a material. As an ISO-17025 accredited environmental compliance test lab, we realize the importance of AECTP climatic compliance testing.

Meeting the environmental and thermal shock requirements can be difficult. We understand the challenges and guide companies through the process. 

Keystone’s engineers take a consultative approach throughout the entire test program. We offer competitive pricing and volume discounts. Our proven process helps avoid product launch delays. Keystone Compliance creates an accurate test plan to eliminate expensive over-testing. 

Request a quote and find out first hand about our competitive pricing, timely process, and outstanding reputation. Contact us to receive more information on AECTP method 304 thermal shock testing.

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.

Additionally, 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 actual 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 304 Thermal Shock Compliance Testing

The thermal shock test method is used when the material is deployed where sudden major changes in temperature are experienced. AECTP 304 can also be used to reveal safety problems. Lastly, potential flows in the material may also be revealed. 

AECTP 304 thermal shock testing is carried out to determine if:

  1. Material safety is affected by exposure to sudden, extreme changes in temperature.
  2. The material can be handled and operated after sudden temperature changes associated with actual service conditions.
  3. The material experiences damage during or after experiencing thermal shock.

On the other hand, this method is not suitable if the actual transfer time in the environment will not produce a significant thermal shock. The thermal shock standard does not address shocks by the internal generation of heat. Nor does the standard address thermal shock caused by rapid warm-up by engine compressor bleed air.

Sudden temperature changes can have temporary or permanent effects on a material. These effects impair the performance of the material by changing its properties. Below are examples of problems that can result from thermal shock.


  • Shattering of glass vials and optical equipment
  • Binding or slackening of moving parts
  • Cracking of solid pellets or grains in explosives
  • Differential contraction or expansion of dissimilar materials
  • Deformation or fracturing of components
  • Cracking of surface coatings
  • Leakage from sealed compartments
  • Failure of insulation


  • Separation of constituents
  • Failure of chemical agent protection
  • Changes in electrical components
  • Electronic or mechanical failures due to rapid water or frost formation
  • Excessive static energy

AECTP 304 Temperature Shock Compliance Testing Procedures

Two procedures can be conducted for this test standard:

Procedure I

This procedure employs constant temperature at each of the extreme shock conditions. In many instances, thermal shock outweighs the other thermal effects. This is particularly true when more severe shocks are desired.

With the test item in the chamber, the air temperature is adjusted to an extreme low temperature for a specified period. Next, the item is transferred in no more than one minute. Depending on the number of cycles chosen, the unit is then returned to standard ambient conditions.

Procedure II

Procedure II is used because the upper temperature follows part of an appropriate diurnal cycle. The test conditions are considered from the expected exposure temperatures and the material’s logistic configuration.

Similar to Procedure I, the unit is adjusted to the low-temperature extreme. Next, the unit is transferred to the maximum air temperature cycle. As soon as the chamber door is shut and the high temperature is restored, the chamber is cycled through part of the diurnal cycle until the chamber reaches the test item response temperature.

Testing Parameters

The temperature levels are determined in relation to the use of the material. Next, the transfer time must reflect the time associated with the actual thermal shock in the life cycle.

Generally, relative humidity is not controlled. Relative humidity usually has a significant influence on some materials during the thermal shock test and must be considered prior to testing.

At the end of either test procedure, the unit is examined and, if appropriate, operated. The results are recorded within a report.

Expert AECTP Method 304 Thermal Shock Compliance Testing

In addition to environmental thermal shock testing, Keystone has a full scope of expertise including fungus, vibration, and ingress protection (IP Code). Keystone has a full lab of test equipment which permits us to provide short lead times on scheduling.

Ready to get started? We are. Contact us to see why so many companies work with Keystone each year to achieve their environmental standard test needs.

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