Pressure or altitude testing is essential for military, industrial, and consumer applications where products or components need to function or be transported in low-pressure environments or withstand rapid decompression in combination with climate control. If your products encounter these environments, or you need to conform to a military or aviation test standard including but not limited to MIL-STD-810 or RTCA DO-160, an altitude test chamber may be the solution you need.
What are the Primary Uses for Altitude Chambers?
Unlike hypobaric chambers used to study the effects of high terrestrial altitude and hypoxia on human physiology, industrial altitude chambers create far more extreme and combined environments including altitude, temperature, humidity, icing, and in some cases, vibration. By combining multiple environments, your products can undergo the qualification testing necessary to simulate real-world conditions. Here are some considerations as you consider investing in an altitude chamber.
By utilizing vacuum pumps of various types and sizes, most altitude chambers are capable of standard vacuum conditions replicating 100,000 ft. with extended ranges available to 200,000 ft. To simulate sudden loss of cabin pressure, some altitude testing chambers can simulate rapid decompression by quickly and dramatically reducing pressure in 15 seconds or less. Alternately, using compressed air or inert gas, altitude chambers can be pressurized to simulate sub-sea or sub-site level altitude.
Using either single-stage or cascade refrigeration, most altitude chambers are designed to provide combined altitude and temperature simulation up to 65,000 ft., allowing for a wide range of combined temperature and altitude profiles. Additionally, altitude chambers can be dual-purposed as temperature-only chambers with temperature ranges of -73°C (-100°F) to 180°C (356°F).
The ability to simulate humidity at ground level in conjunction with temperature/altitude in a cyclical profile is essential in testing the durability and longevity of many critical flight components. In special cases like icing tests, combined environment testing must include control of temperature, humidity, and altitude simultaneously. Most combined environment altitude chambers can be dual-purposed as temperature and humidity chambers, providing ranges of 5% to 95% relative humidity (RH) within the bounds of an 85°C (185°F) maximum dry bulb and a 4°C (40°F) minimum dewpoint.
Under unique circumstances, vibration compatibility with an electrodynamic or mechanical vibration system can integrate with altitude, temperature, and humidity chambers. Real-world applications require unique qualification testing for aerospace and avionics equipment.
Industry Requirements for Altitude Chambers
There are limitless altitude tests that can be tailored for consumer products and packaging, but for military and aerospace applications there are two primary sources of specifications and guidelines, which are often updated to reflect agreed-upon protocol changes and enhancements to ensure products meet the rigorous demands of the industry. Key industry requirements utilizing altitude testing include:
- MIL-STD-810 – The United States DoD released the updated revision H, a successor to MIL-STD-810G, in January 2019. A MIL-STD is simply a list of testing guidelines and standards that ensure commonality in military applications. While MIL-STD-810H covers a wide range of testing methodologies, and several “Methods” within MIL-STD-810H specifically address altitude and/or combined environment testing.
- RTCA DO-160 – This international standard, established in 1958 and most recently updated in 2011(DO-160G), is defined as the Environmental Conditions and Test Procedures for Airborne Equipment. The objectives of the standard are to demonstrate the performance characteristics of devices and equipment subjected to environmental conditions present in airborne equipment. Much like MIL-STD-810H, RTCA DO-160G covers a wide range of testing methodologies, including several “Sections” which specifically address altitude and/or combined environment testing.
Both standards make allowances for tailoring tests based on unique or specific products and/or flight or mission profiles, but in most cases test profiles are developed around four main procedural guidelines:
- Storage – Tests materials and/or packaging transported or stored at high or low altitudes, with or without combined environment testing.
- Operation – Evaluates performance of products or equipment at high or low altitudes, with or without combined environment testing.
- Rapid Decompression – Evaluates the potential impact to personnel, products, or equipment resulting from rapid depressurization.
- Explosive Decompression – Similar to Rapid Decompression, but simulating instantaneous decompression, such as when a pressurized aircraft cockpit becomes compromised.
Other Considerations for Altitude Chambers
With any purchase of environmental test equipment, there are several additional considerations for altitude chambers.
- Chamber Dimensions – How large is your unit under test (UUT)? What quantity will you need to test at one time? Do you have move-in restrictions to your facility, or building infrastructure constraints for getting the chamber to its final place of performance?
- Cooling and Heating Capacity – What is the temperature range requirement for your product? Does your product generate any heat under test? How quickly do you need to heat or cool the chamber? Will your testing capabilities expand in the future?
- Altitude – What is the altitude range requirement for your product? How quickly do you need to change the altitude for your testing? Does your product discharge air or gas into the chamber during altitude tests?
- Humidity – What is the humidity vs temperature testing range requirement for your product? Is humidity required in conjunction with altitude testing? Does your product discharge or remove moisture inside the chamber during tests?
- Combined Environment – Is humidity, icing, and/or vibration required?
The best altitude test chambers are designed and manufactured to meet your exacting specifications. The more information you can provide our Application Engineers, the better the outcome in meeting your requirements, both for now and the future. No two altitude chambers are exactly alike, which makes a collaborative effort between the customer and the manufacturer early in the development process critical.
Russells Technical Products understands altitude test chambers and has the solution to match your requirements. We provide one-on-one attention to our customers to make sure that from start to finish, you stay involved in the process and communicate with a single point of contact at the factory. That’s why we’ve been trusted to design and build some of the most complex altitude systems ever created. Contact us today to start a conversation and learn for yourself why we’ve been supplying superior altitude test chambers for over 50 years.