What Is Altitude?
The altitude test is one in which the sample is held at a low air pressure representing high altitude to assess function, sealing and cooling performance.
Purpose of Altitude
The purpose is to verify that products operating at high altitude or transported by air remain safe and functional at low pressure.
Which Products Is Altitude Applied To?
- Aerospace avionics units
- Electronic devices used at high altitude
- Battery systems
- Pressure-sensitive enclosures
- Fan-cooled devices
In Which Sectors Is Altitude Used?
Standards Related to Altitude
- IEC 60068-2-13series of environmental testing methods test
- RTCA DO-160 Section 4
- MIL-STD-810 Method 500
- UN 38.3 T.1
Altitude Conditions
- Pressure
- Defined in the specification; absolute pressure corresponding to altitude
- Time
- Holding time defined in the standard
- Temperature
- If necessary, apply combined with low temperature.
- Operating condition
- Defined as running or off
Equipment for Altitude
- Vacuum chamber (pressure-controlled)
- Pressure and temperature measurement system
- Function-monitoring rig
- Mass measurement (for sealing assessment)
Sample Requirements for Altitude
- The sample must be installed in its typical mounting configuration
- Function and, if required, mass must be measured before the test
- Cooling performance must be monitored for fan-cooled devices
- Sealing elements must be in the assembled state
Duration of Altitude
Depends on the duration defined in the specification; typically hours.
Altitude Procedure
- 1The sample is placed in the chamber and initial measurements are taken.
- 2Pressure is lowered to the defined value in a controlled manner.
- 3It is maintained for the defined duration; function is monitored in the operational test.
- 4The pressure is returned to ambient.
- 5Function, sealing and visual condition are assessed.
Altitude Acceptance Criteria
The acceptance criterion is defined in the specification: continuity of function, no leakage, and adequate cooling performance.
Evaluation of Results
Air cooling weakens at low pressure, so the temperature rise is also assessed. Whether deformation occurs due to the pressure change is examined.
Altitude Report
- Standard applied
- Pressure, duration and temperature conditions
- Operating condition
- Function and sealing results
- Measured temperatures
Accreditation
EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.
Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.
Scope and authorisationsRelated Regulations
- Aerospace equipment requirements
- UN 38.3 (battery transport)
Environmental and Climatic Testing — What Does This Testing Field Cover?
The section below describes the field that the Altitude test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.
Environmental testing shows whether a product withstands ambient factors such as temperature, humidity, pressure, solar radiation, dust, water and corrosive atmospheres. The aim is not to break the product but to bring forward, in ACCELERATED form, the conditions it will meet over its life.
Test profiles are derived from the product's real exposure, and that derivation is the actual engineering work of the field. A device operating in an enclosed office and one mounted on a pole are not tested with the same profile. The IEC 60068 series defines general methods, MIL-STD-810 military profiles, RTCA DO-160 aviation profiles and the ISO 16750 series location-based automotive profiles. A test applied without a profile selection produces both unnecessary cost and false confidence.
Temperature tests simulate three separate phenomena and all three produce different failure modes. Steady high/low temperature tests whether the material can operate at that temperature. Temperature CYCLING creates fatigue at joints between materials with different expansion coefficients — solder cracks appear here. Thermal SHOCK intensifies this effect through an abrupt transition.
There is a distinction in humidity testing too. Steady damp heat shows the diffusion of moisture into the material and its effect on insulation properties. Cyclic damp heat creates condensation: water droplets form on the cooling surface, and this is far more aggressive than dry humidity. Water ingress into enclosures, increased leakage current and corrosion usually appear in the cyclic test.
Dust and water protection is a separate body of work and is expressed by the IP code. The point to note here is that an IP test is not a DURABILITY test: it shows that protection is provided under defined and short-duration conditions, not resistance to long-term immersion or pressure washing.
The most common mistake in this family is translating a test result directly into a LIFE PREDICTION. Accelerated tests are designed for comparison and design verification; a reliable conversion between hours in a chamber and years in the field can only be established with a material-specific acceleration model calibrated against field data.
Functional monitoring determines the value of the test. Keeping a product in a temperature chamber and then switching it on does not show what happened DURING the test. In critical applications the product is operated throughout the test and its parameters are monitored; intermittent faults that appear and disappear can only be caught this way.
Method groups in this field
Temperature
Dry heat, cold, change of temperature and thermal shock; steady and cyclic profiles.
Humidity
Steady damp heat and cyclic damp heat; cycles with condensation are more aggressive.
Water and dust
IP protection tests: dripping, spraying, jets, immersion and dust tightness.
Radiation and ageing
Accelerated ageing by xenon arc and fluorescent UV, solar radiation simulation.
Pressure and altitude
Low pressure (altitude) and rapid pressure change tests.
Corrosive atmosphere
Salt spray, mixed flowing gas corrosion (simulating industrial atmospheres), mould and fungus tests.
Commonly confused in this field
- Test duration cannot be converted into field life; a conversion made without an acceleration model is misleading.
- Temperature cycling and steady temperature produce different failure modes; neither replaces the other.
- If the product is not operated during the test, intermittent faults remain invisible; functional monitoring determines the value of the test.
- IP protection is not evidence of durability; it shows protection under defined and short-duration conditions.
- A test applied without profile selection both increases cost and gives false confidence.
- The mounting and orientation arrangement affects the result; the report must document it.
Which decisions these results support
- Design verification and qualification
- Declaration of the protection class and operating temperature range
- Reproducing field failures in the laboratory and root cause analysis
- Supplier component approval
- Decisions on warranty period and storage conditions
Related Tests
Frequently Asked Questions About Altitude
According to which standard is Altitude made?
Altitude is executed in scope IEC 60068-2-13, RTCA DO-160 Section 4, MIL-STD-810 Method 500 and UN 38.3 T.1. The limit values and acceptance criteria to be applied are defined in the product standard; The version valid for your product is confirmed in writing at the offer stage.
Which products does Altitude apply to?
Mainly applied to Aerospace avionics units, Electronic devices used at high altitude, Battery systems, Pressure-sensitive enclosures and Fan-cooled devices. Whether your product is included in the scope is determined by examining its technical specifications and intended use.
Under what conditions is Altitude done?
The determining parameters are: Pressure — Defined in the specification; absolute pressure corresponding to altitude, Time — Holding time defined in the standard and Temperature — If necessary, apply combined with low temperature.. The full terms are in the "Test Conditions" section on the page and vary depending on the product standard.
What kind of sample is needed for Altitude?
The sample must be installed in its typical mounting configuration, Function and, if required, mass must be measured before the test and Cooling performance must be monitored for fan-cooled devices. The number of samples is determined according to the product standard and the scope to be reported.
How long does Altitude take?
Depends on the duration defined in the specification; typically hours. This duration belongs to the experiment itself; sample preparation, queuing and reporting are also evaluated. A realistic schedule for your product is given in the offer.
What is the Altitude result called "appropriate"?
The acceptance criterion is defined in the specification: continuity of function, no leakage, and adequate cooling performance.