Testing that Reaches the World

MIL-STD-810, Method 501., applies to high or elevated temperature testing to evaluate the performance and durability of equipment when exposed to high-temperature environments. The purpose of high-temperature testing is to ensure that the equipment can operate, function, and maintain its performance under elevated temperature conditions.

Clark Testing engineers conduct MIL-STD-810, Method 501 to assess equipment's ability to withstand and operate in high-temperature environments and help to identify potential issues related to thermal stress, material integrity, component degradation, and functional performance at elevated temperatures.

Method 501 applies controlled temperature conditions typically in environmental chambers or ovens monitored to meet the specific temperature levels. The engineering team at Clark Testing will help to determine the temperature ramp rates, and durations of the tests based on the equipment's intended use and the operating environmental conditions.

MIL-STD-810G specifies different high-temperature test levels that are categorized based on the anticipated temperature conditions. The levels are determined by factors such as the equipment's operating temperature range, storage temperature requirements, and deployment scenarios. These levels help ensure that the equipment is tested under relevant and representative high-temperature conditions.

The standard defines acceptance criteria for high-temperature testing. The criteria may include allowable temperature limits, thermal shock resistance, material degradation, functionality, and other performance parameters. The equipment is assessed based on its ability to withstand the specified high-temperature conditions without sustaining damage or exhibiting performance degradation beyond acceptable limits.

The standard serves as a baseline and can be tailored by Clark’s engineering staff to meet specific testing needs based on the application and environmental conditions in which the equipment will be deployed.

This Method includes three test procedures:

• Procedure I (Storage)
• Procedure II (Operation)
• Procedure III (Tactical-Standby to Operational)

All three procedures involve temperature conditioning and performance testing but differ based on the temperature load prior to and during performance tests.

Procedure I assesses the effects of high temperature storage on subsequent material performance. Procedure I investigates how high temperatures during storage affect integrity and safety/performance of material. This test procedure includes exposing the test item to high

temperatures (and low humidity where applicable) that may be encountered in the materiel's storage situation, followed by an operational test at ambient conditions.

Procedure II assesses the effects of high temperatures during performance to investigate how high ambient temperatures may affect material performance during operation. There are two ways to perform Procedure II:

1. Expose the test item to cyclic chamber conditions with the test item operating either continuously or during the period of maximum response (highest item temperature).

2. Expose the test item to a constant temperature and operate the test item when its temperature stabilizes. (To be used only for items situated in close proximity to heat- producing equipment or when it is necessary to verify operation of an item at a specified constant temperature.)

Procedure III assesses the tactical-standby to evaluate the ability of material that has soaked in the sun in a high temperature environment to become operational in a relatively short period of time. This procedure is not a substitute for solar radiation but evaluates the material’s performance at the operating temperatures after being presoaked at non-operational temperatures.

Clark’s test engineering team help customers determine the test duration based on an estimate of the number of cycles required to satisfy the design requirements. The test duration may be as significant as the temperature itself. Procedures I and II could expose the test items to cyclic temperatures, the number of cycles is critical. (Cycles are 24-hour periods unless otherwise specified).

Procedure I, the number of cycles for the storage test is set at a minimum of seven to coincide with the one percent frequency of occurrence of the hours of extreme temperatures during the most severe month in an average year at the most severe location. (The maximum temperature occurs for approximately one hour in each cycle.) When considering extended storage, critical materials, or materials determined to be very sensitive to high temperature, we would increase the number of cycles to assure the design requirements are met.

Procedure II covers operational high temperature, the minimum number of cycles for the operational exposure test is three. This number is normally sufficient for the test item to reach its maximum response temperature.

Climatic conditions:

Identify the appropriate climatic conditions for the geographic areas in which the material will be operated and stored. There are two climatic categories where high temperatures are typically encountered: Hot Dry and Basic Hot.

Determine high temperature levels with respect to:

a. Climatic area of concern.

b. Exposure to solar radiation: Is this exposure directly on the material, shipping container, protective package shelter, etc.

c. Analysis of the path of heat transfer from the ambient air and solar radiation to the material.

Many parts of the world, extending outward from the hot dry category of the southwestern United States, northwestern Mexico, central and western Australia, Saharan Africa, South America, southern Spain, and southwest and south-central Asia. These areas would fall into category of Basic Hot. Southwest and south-central Asia, southwestern United States, Saharan Africa, central and western Australia, and northwestern Mexico fall into category Hot Dry.

Call or email Clark Testing. Our engineers will develop a test plan and conduct testing services to ensure that the equipment can operate, function, and maintain its performance under elevated temperature conditions.