What Is IEC 60068-2-13:2021?
IEC 60068-2-13:2021 is an international environmental testing standard titled:
Environmental testing – Part 2-13: Tests – Test M: Low air pressure
The standard applies to specimens that can experience reduced air pressure during:
• Transportation
• Storage
• In-service operation
The purpose is to determine whether a product can withstand the specified low-air-pressure environment without unacceptable degradation of its required performance or physical integrity.
The standard belongs to the IEC 60068 environmental testing series administered by IEC Technical Committee 104, which covers environmental conditions, classification and methods of test.
What makes the 2021 edition important?
The 2021 edition is a technical revision of the previous 1983 edition.
IEC identifies two particularly significant changes:
1. Test severities were aligned with recently revised parts of IEC 60068 and the IEC 60721 series.
2. Annex A was added to provide guidance for selecting the duration of exposure.
This means an engineering team using IEC 60068-2-13:2021 should not simply copy an old low-pressure test profile from an earlier project.
The applicable severity and exposure duration should be established from the current product requirement and environmental profile.
What Does Test M Evaluate?
Test M evaluates product behavior under reduced atmospheric pressure.
Low pressure can change several physical conditions surrounding a product. Depending on the product design, these changes may influence thermal performance, mechanical integrity, electrical behavior, sealing and functional operation.
Thermal behavior
As air density decreases, heat transfer through the surrounding atmosphere can change.
This can become important for products containing:
• Power electronics
• Processors
• Batteries
• Motors
• Power supplies
• Heat-generating components
• Electronic assemblies
A product that passes a test at normal atmospheric pressure may not exhibit identical thermal behavior under reduced pressure.
Mechanical effects
Pressure differences can affect enclosed or sealed structures.
Potential concerns include:
• Housing deformation
• Seal performance
• Leakage
• Pressure differential
• Structural integrity
• Component movement
Electrical behavior
Reduced pressure can also be relevant to electrical insulation and discharge behavior for susceptible products.
The actual failure mechanism depends strongly on:
• Voltage
• Geometry
• Insulation system
• Product construction
• Pressure
• Operating condition
Therefore, Test M should be designed around the actual product risk rather than treated as a generic altitude demonstration.
Functional performance
A specimen may be tested:
• Non-operating
• Operating
• Under electrical load
• Under mechanical load
• With continuous functional monitoring
The required condition should be defined by the relevant product specification.
IEC 60068-2-13 Pressure and Altitude Levels
A common mistake in environmental testing is to specify only an altitude.
For example:
“Test the product at 10,000 m.”
For an engineering test specification, this is incomplete unless the corresponding pressure condition and other test parameters are clearly established.
Pressure is the controlled environmental parameter
IEC 60068-2-13:2021 defines low-air-pressure test severities and aligns the severity framework with relevant IEC 60721 environmental classifications.
An altitude may be used to communicate the intended environmental condition, but the test equipment must control the actual air pressure.
This gives the laboratory a measurable and reproducible test condition.
What should the test specification define?
A useful test specification should identify:
Target air pressure
Pressure tolerance or control requirement
Exposure duration
Specimen operating condition
Required temperature, if applicable
Measurement requirements
Recovery requirements
Acceptance criteria
Why pressure matters more than an altitude label
Two laboratories can interpret an altitude requirement differently if they use different assumptions about atmospheric conditions.
A pressure-based specification is more directly measurable.
For procurement, instead of asking:
“Can the chamber simulate 50,000 ft?”
a better question is:
“Can the system achieve and maintain the specified test pressure with documented accuracy and stability?”
This creates a much clearer technical basis for comparing equipment suppliers.
How to Determine Test Duration
Exposure duration is one of the important changes to consider in the 2021 edition.
IEC states that the revised edition added Annex A, guidance on selecting the duration of exposure.
Therefore, test duration should not be treated as an arbitrary fixed value applicable to every product.
Step 1 — Identify the environmental exposure
Determine how long the product is expected to experience reduced atmospheric pressure during:
Transportation
Storage
Operation
Qualification
Customer-specific use conditions
Step 2 — Identify the purpose of the test
The objective could be to evaluate:
Functional operation
Mechanical integrity
Sealing
Electrical performance
Thermal behavior
Long-duration environmental compatibility
Step 3 — Define the specimen operating condition
The same product may require different test conditions depending on whether it is:
Powered off
Powered on
Operating continuously
Operating intermittently
Under representative load
Step 4 — Determine the applicable exposure duration
The duration should be established according to the relevant specification and the guidance in IEC 60068-2-13:2021.
Step 5 — Define acceptance criteria
Before testing begins, specify what constitutes acceptable performance after exposure.
This could include:
Functional operation
Electrical parameters
Leakage performance
Mechanical integrity
Visual condition
Performance degradation limits
Engineering principle
Pressure level and exposure duration should be treated as a test pair.
Selecting an extreme pressure without considering exposure duration may produce a test that does not accurately represent the intended product environment.
Low Air Pressure Test Chamber Requirements
A low-air-pressure test chamber is not simply a vacuum vessel.
For IEC 60068-2-13 applications, the system must establish and maintain the specified environmental condition in a controlled and measurable manner.
1. Pressure range
The equipment should be evaluated against the actual required pressure range.
Ask the supplier for:
• Minimum achievable pressure
• Normal operating pressure range
• Pressure control range
• Pressure stability
2. Pressure measurement
The system should provide appropriate pressure measurement capability.
Important parameters include:
• Sensor technology
• Measurement range
• Accuracy
• Resolution
• Calibration
• Data acquisition
3. Pressure control
The chamber should be capable of controlled pressure reduction and controlled maintenance of the target pressure.
For qualification testing, stability during the exposure period is particularly important.
4. Controlled pressure recovery
The system should allow the specimen to return to normal atmospheric pressure in a controlled manner when required by the test program.
5. Chamber volume
The usable test volume should account for:
• Product dimensions
• Fixtures
• Number of specimens
• Instrumentation
• Cable routing
• Required clearances
6. Electrical feedthroughs
For powered specimens, the chamber may require:
• Power feedthroughs
• Signal feedthroughs
• Thermocouple connections
• Data acquisition interfaces
• Communication interfaces
7. Data acquisition
For engineering qualification, pressure data should be recorded together with the relevant specimen measurements.
A useful system can record:
Pressure + Time + Test Stage + DUT Data + Alarm Status
8. Calibration and traceability
Procurement teams should request:
• Pressure calibration certificates
• Sensor specifications
• Calibration traceability
• Equipment acceptance documentation
• Software/data records
IEC 60068-2-13 vs IEC 60068-2-39
| Engineering Factor | IEC 60068-2-13:2021 — Test M | IEC 60068-2-39:2015 |
|---|---|---|
| Standard title | Environmental testing – Part 2-13: Tests – Test M: Low air pressure | Environmental testing – Part 2-39: Tests and guidance: Combined temperature or temperature and humidity with low air pressure tests |
| Primary purpose | Evaluate the ability of components, equipment or other products to withstand low air pressure | Evaluate the effects of combined temperature or temperature/humidity and low air pressure |
| Primary environmental stress | Low air pressure | Low air pressure + temperature, or low air pressure + temperature + humidity |
| Pressure testing | Yes | Yes |
| Temperature testing | Not the primary test condition | Yes |
| Humidity testing | Not the primary test condition | Yes, where specified |
| Combined environmental testing | Limited to the low-pressure condition | Specifically designed for combined conditions |
| Typical test objective | Determine whether a product can be used, transported or stored under reduced atmospheric pressure | Determine how combined temperature/temperature-humidity and low pressure affect equipment or components |
| Typical applications | Aerospace electronics, avionics, sensors, electronic assemblies, high-altitude equipment | Aerospace and electronic equipment exposed to simultaneous thermal and low-pressure environments |
| Pressure parameter | Test air pressure is specified in the relevant specification; preferred values are provided in the standard | Low air pressure is selected together with the applicable temperature/humidity condition |
| Altitude relationship | Provides an air-pressure/approximate-altitude relationship for severity selection | Uses low pressure as one component of a combined environmental condition |
| Exposure duration | Duration is specified in the relevant specification; 2021 edition includes Annex A guidance for selecting exposure duration | Duration is selected as part of the combined temperature/pressure/humidity test severity |
| Test severity concept | Primarily air pressure + exposure duration | Temperature + low air pressure + duration, with humidity included where applicable |
| Specimen operating condition | Defined by the relevant specification | Defined by the relevant specification and combined test profile |
| Thermal effects | Considered only insofar as they result from the low-pressure environment or specimen characteristics | Directly evaluated as part of the combined temperature/low-pressure condition |
| Humidity effects | Not the primary purpose | Specifically addressed when temperature, humidity and low pressure are combined |
| Heat-dissipating specimens | Special chamber considerations may be required because reduced pressure changes heat transfer | More significant because temperature and low pressure are deliberately combined |
| Chamber requirement | Low-pressure environmental test chamber capable of achieving and maintaining specified pressure | Combined environmental chamber capable of controlling pressure together with temperature and, where required, humidity |
| Pressure control | Required | Required |
| Temperature control | Only required if separately specified | Integral to the combined test where temperature is specified |
| Humidity control | Not normally required for Test M alone | Required when the test profile includes temperature + humidity + low pressure |
| Data monitoring | Pressure, time and relevant DUT parameters | Pressure, temperature, humidity, time and relevant DUT parameters |
| Main procurement question | “Can the chamber accurately achieve and maintain the required low-air-pressure condition?” | “Can the chamber simultaneously control pressure and the required temperature/humidity profile?” |
| Use when | Low air pressure is the principal environmental stress | The combination of low pressure with temperature or temperature/humidity is important to the product stress or failure mechanism |
| Related TestEQ equipment | Altitude / low-pressure test chamber | Temperature-altitude / combined environmental test chamber |
| Key engineering distinction | Pressure-focused environmental test | Combined environmental test |
Use IEC 60068-2-13:2021 when low air pressure is the primary environmental stress. Use IEC 60068-2-39:2015 when temperature or temperature and humidity must be combined with low air pressure because the combined environment is important to the product's stresses or failure mechanisms.
IEC 60068-2-13 vs MIL-STD-810 Method 500
IEC 60068-2-13 and MIL-STD-810 both address environmental effects associated with reduced atmospheric pressure, but they are different standards systems.
IEC 60068-2-13
IEC 60068-2-13:2021 is specifically titled:
Environmental testing – Part 2-13: Tests – Test M: Low air pressure
It establishes an international environmental test method for specimens exposed to low air pressure.
MIL-STD-810
MIL-STD-810 is an environmental engineering standard covering environmental considerations and laboratory tests for materiel.
The U.S. Department of Defense's ASSIST database currently lists MIL-STD-810 as an active document, dated May 18, 2022. The standard emphasizes environmental tailoring rather than imposing one universal test profile on every product.
Key engineering difference
The question should not simply be:
“Which standard is better?”
Instead:
“Which standard is specified by the product qualification requirement?”
For an IEC-based customer requirement, use the applicable IEC method.
For a defense or military procurement requirement explicitly calling for MIL-STD-810, the applicable Method 500 procedure and tailoring requirements should be followed.
Important procurement point
A chamber advertised as a “MIL-STD-810 altitude chamber” does not automatically mean that the complete test program is compliant with IEC 60068-2-13.
The equipment capability and the test method are related, but they are not the same thing.
What Engineers Should Specify When Buying a Low Pressure Test Chamber
The equipment specification should start from the test requirement.
Instead of purchasing based on a chamber name such as:
“Altitude Chamber”
or:
“Vacuum Chamber”
define the actual environmental requirements first.
Recommended procurement specification
| Parameter | Engineering Requirement to Define |
|---|---|
| Test Standard | IEC 60068-2-13:2021 |
| Test Method | Test M — Low Air Pressure |
| Pressure Range | Required minimum and maximum operating pressure |
| Target Pressure | Required test pressure / setpoint |
| Pressure Control | Required pressure control accuracy and stability during exposure |
| Pressure Measurement | Measurement range, accuracy, resolution and calibration requirements |
| Exposure Duration | Required exposure time at the specified pressure |
| Chamber Volume | Product dimensions + fixtures + instrumentation + required clearance |
| DUT Condition | Operating, non-operating, or operating under specified load |
| Temperature | Required temperature range when temperature is part of the test profile |
| Humidity | Required humidity range when specified by the test program |
| Feedthroughs | Power, signal, thermocouple, sensor and communication connections |
| Data Logging | Continuous recording of pressure, time and relevant DUT parameters |
| Calibration | Traceable calibration for pressure and other critical measurement systems |
| Safety | Pressure/vacuum protection, alarms, interlocks and emergency protection |
| Software | Programmable test profiles, monitoring, alarms, data storage and report generation |
| Recovery | Controlled return from low pressure to atmospheric pressure |
| Customization | Custom chamber dimensions, fixtures, feedthroughs and DUT interfaces |
A low air pressure test chamber should be specified according to the actual IEC 60068-2-13:2021 Test M requirements, rather than by maximum simulated altitude alone.
Five questions to ask the supplier
1. What is the guaranteed pressure range?
Do not rely only on the theoretical ultimate vacuum.
Ask for the usable test range.
2. What pressure stability can be guaranteed at the required setpoint?
This is more relevant to a long-duration qualification test than the maximum vacuum capability alone.
3. How is pressure measured and calibrated?
The sensor range and calibration should match the actual test requirement.
4. Can the specimen operate during the test?
If the DUT must operate under low pressure, confirm the required feedthroughs, instrumentation and thermal management.
5. Can the system generate a complete test record?
For qualification work, traceable test data is part of the engineering value of the equipment.
IEC 60068-2-13 Test Report Requirements
A useful IEC 60068-2-13 test report should make the test condition reproducible and allow another engineer to understand what was actually performed.
The relevant specification and test report are explicitly addressed within the standard structure.
Recommended test report information
Test identification
Standard
Edition
Test method
Test laboratory
Test date
Specimen information
Product name
Model
Serial number
Configuration
Quantity
Pre-test condition
Equipment information
Chamber identification
Pressure measurement system
Calibration status
Relevant instrumentation
Environmental condition
Target pressure
Actual pressure profile
Exposure duration
Pressure transition
Temperature, where applicable
Operational condition
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Load condition
Monitoring parameters
Functional state
Measurements
Initial measurements
During-test measurements
Final measurements
Abnormal events
Alarm events
Recovery
Recovery condition
Recovery time
Post-test stabilization
Results
Acceptance criteria
Actual observations
Functional results
Physical inspection
Deviations
Final test result
Why the actual pressure profile matters
A report stating only:
“Altitude test completed successfully”
provides limited engineering information.
A stronger report records the actual pressure history and relevant DUT response.
This creates a much more useful qualification record for design engineering, quality assurance and customer audits.
IEC 60068-2-13 Test M: Engineering and Procurement Checklist
Before releasing a purchase specification, confirm:
Test Standard
IEC 60068-2-13:2021
Test Method
Test M — Low Air Pressure
Pressure
Target pressure and required control/stability
Duration
Exposure duration defined according to the applicable specification
Specimen
Dimensions, quantity and operating condition
Environment
Temperature/humidity requirements if applicable
Instrumentation
Pressure, temperature and DUT monitoring
Data
Continuous recording and export requirements
Calibration
Traceable pressure measurement
Safety
Controlled pressure reduction and recovery
Documentation
Calibration, factory testing, operating documentation and test records
A properly defined specification allows engineering, quality and procurement teams to evaluate suppliers using the same technical criteria.
TestEQ Low Air Pressure Test Systems
TestEQ provides environmental test systems for applications involving low air pressure, altitude simulation and combined environmental conditions.
Depending on the project requirement, the system can be configured for:
• Low air pressure testing
• High-altitude simulation
• Temperature-altitude testing
• Combined temperature and low-pressure testing
• Environmental qualification
• Aerospace and avionics testing
• Electronic component testing
• Automotive electronics testing
• Custom chamber configurations
• Product-specific fixtures and instrumentation
For an IEC 60068-2-13 project, TestEQ can evaluate the required pressure range, chamber volume, exposure duration, DUT operating condition, temperature requirements and instrumentation before recommending the equipment configuration.
The objective is not simply to achieve a specified altitude. It is to create a controlled and documented low-air-pressure test environment that matches the actual qualification requirement.
Frequently Asked Questions
1.What is IEC 60068-2-13:2021?
IEC 60068-2-13:2021 is the fifth edition of the IEC environmental testing standard for Test M: Low Air Pressure. It applies to specimens that may experience low air pressure during transportation, storage or service.
2.What does Test M mean in IEC 60068?
Test M is the low-air-pressure test method defined in IEC 60068-2-13.
3.Is IEC 60068-2-13 an altitude test standard?
It is a low-air-pressure environmental test standard. Altitude can be used to describe an equivalent environmental condition, but the controlled test parameter is air pressure.
4.What products use IEC 60068-2-13?
Typical applications can include aerospace equipment, avionics, electronic assemblies, sensors, communication equipment, automotive electronics and products intended for reduced atmospheric-pressure environments.
5.Does IEC 60068-2-13 specify test pressure?
The standard provides test severities for low-air-pressure testing. The applicable severity should be selected according to the relevant product specification and environmental requirement. The 2021 edition aligned the severity framework with relevant IEC 60721 classifications.
6.Does IEC 60068-2-13 specify test duration?
Yes. The 2021 edition includes Annex A, which provides guidance for selecting the duration of exposure.
7.What is the difference between IEC 60068-2-13 and IEC 60068-2-39?
IEC 60068-2-13 focuses on low air pressure, while IEC 60068-2-39 addresses combined temperature or temperature/humidity with low air pressure.
8.What is the difference between IEC 60068-2-13 and MIL-STD-810?
IEC 60068-2-13 is an IEC environmental test method specifically addressing low air pressure. MIL-STD-810 is a broader U.S. military environmental engineering standard based on environmental tailoring and laboratory test methods.
9.What chamber is required for IEC 60068-2-13?
A suitable system must be capable of achieving and maintaining the specified low-air-pressure condition with appropriate pressure measurement, control, data acquisition and specimen interfaces.
10.Can a low-pressure chamber also control temperature?
Yes. If the test program requires simultaneous temperature and low-pressure conditions, the chamber configuration should be designed around the applicable combined environmental test requirement.
11.What should I provide when requesting an IEC 60068-2-13 chamber quotation?
Provide the required pressure, exposure duration, product dimensions, specimen quantity, operating condition, temperature requirements, instrumentation, feedthrough requirements and applicable test standard.
12.Can TestEQ customize an IEC 60068-2-13 test system?
Yes. TestEQ can configure low-pressure and altitude environmental test systems according to required pressure range, chamber volume, temperature conditions, specimen operation, instrumentation and test-profile requirements.
