One of the many important tests that customers need to conduct on their products for validation is sand and dust testing. The purpose of testing for sand and dust ingress is to ensure the proper functionality and durability of devices and mechanisms in varying environments. Products may operate without issues in a laboratory with controlled air and temperature, but products operating in the open world are subjected to the ambient air containing microparticles. Failure from sand and dust ingress can occur in many different ways: a fan-cooled power supply will have dust build-up near ventilation points, leading to overheating; solar panels will be covered in dirt and sand, reducing efficiency.
Dust chambers are used to measure a product’s casing or enclosure’s ability to prevent dust ingress. Such products are rated by the IP Code (International Protection Marking), established by the International Electrochemical Commission (IEC) standard 60529. This standard specifies multiple levels of protection from both dust and water ingress with detailed specifications for each level. The first digit refers to solids, second digit refers to liquids. For example, a product rated IP5X is dust protected, which means that dust ingress not fully prevented but is within tolerances of adequate product functionality; an IP6X rated product is fully protected from dust ingress. A product rated IP67 is dust tight and water tight: it is guaranteed to be protected from dust ingress and water ingress up to 13 feet deep. These definitions are backed by IEC-60529.
| IP Code Rating | IPXX (solid) | IPXX (liquid) |
| 0 | No protection | No protection |
| 1 | Protection from solids > 50 mm | Protection from water drops |
| 2 | … solids > 12.5 mm | … water drops at 15° angle |
| 3 | … solids > 12.5 mm | … water spray at 60° angle |
| 4 | … solids > 1.0 mm | … water splashing at all angles |
| 5 | Good protection from dust | … water jets at all angles |
| 6 | Full protection/dust tight | … powerful water jets, waves |
| 7 | N/A | … temporary < 1 m submersion |
| 8 | N/A | … permanent < 3 m submersion |
Testing for sand and dust ingress is especially important for microelectronics and integrated circuits where consistent operation is required indefinitely, or for devices and mechanisms which are expected to operate in harsh environments. Settling dust chambers test products by essentially showering the product with coats of dust within a chamber; this simulates the natural accumulation of dust from a product sitting in a typical location open to the atmosphere.
Relia Test Labs uses the Nvirotest Solutions© LRHS-512DUST which has an interior volume of 0.512 m3, a capable dust concentration of 2.0-4.0 kg/m3, and an air velocity up to 2 m/s. Compatible particulates include dry talcum powder, silicate cement, or smoke ash. This chamber uses a blower motor to pump particulates into the chamber, scattering over the product. A vibration motor is used to pull dust off of the chamber walls. The unit includes a flowmeter and pressure gauge for measuring air flow and pressure respectively, and also features a viewing window for observing tests in action.
The diagram below gives an example of a valid dust settling appatarus defined by the Mil-Std 810F, 510.4.
The Nvirotest Solutions© H-DTDS-216 is a Dual Dust and Sand Chamber used by Relia Test Labs for more in depth reliability testing. This unit simulates blowing dust and sand in a controlled atmosphere for harsher stress testing. The 216 L (7.6 ft3) chamber interior is composed of high-quality SUS#304 stainless steel with high temperature protection. The exterior is formed with solid baked painted steel plating. The chamber utilizes a high-pressure air circulating fan to blow sand and dust, with wind speeds ranging from 1.0 – 29.0 m/s controlled with a speed adjustor. An electric heater with SSR and PID control is used to regulate temperature. The sand and dust volume and consistency can be automatically adjusted with electronic concentration sensors (3.0 – 17.6 g/m3).
The Nvirotest Solutions© settling dust chambers are capable of several ingress protection standards, including IEC-60259, DIN-40050, IP5X, IP6X, SAE-J575, ISO-20653, and IEC-60068-2-68. Test subjects cover more than just electronics - the DIN-40050, ISO-20653, and SAE-J575 standards are intended for road vehicle component certification. The H-DTDS-216 chamber achieves Mil-Stds 810F, 510.4, Procedures I and II (blowing dust and blowing sand respectively).
More in-depth information regarding the Mil-Stds can be found in the source material linked below:
Relia Test Labs is accredited with the ISO/IEC 17025 testing and calibration laboratories standard, making us an attractive solution for your testing needs in the heart of the Silicon Valley.
Why do you need dust testing?
Many electronics and machinery remains in one place for long periods of time, and therefore accumulates dust, especially in environments with poor air flow, such as office buildings, laboratories, and store rooms. Settling dust testing determines a product’s ability to function in the real world, where dust penetrates into cracks, openings,and joints, and interferes with moving parts, mating parts, and filters. The test also evaluate the effectiveness of the filters.
The test conditions like temperature, storage method of the product (covered, uncovered, open, etc.) and type of dust are determined based on the location where the product is meant to be used. The product is placed in a dust chamber that is set to appropriate conditions for the product’s target location, and then the chamber allows dust to settle on the product in a controlled environment.
The most commonly followed standard for settling dust testing is Mil-Std 810G, in which the air velocity does not exceed .2 m/s to allow the dust to settle rather than blow, and the relative humidity does not exceed 30% to prevent caking of dust.The dust particles themselves are no larger than 105 μm.
Hastest Solutions has settling dust testing chambers available for testing that can also be made to follow the following additional standards:
- IEC-600529
- DIN-40050 IP5X & IP6X,
- SAE-J575
- ISO-20653
- IEC-60068-2-68
Settling dust testing is useful in the LED, Smart City Products, and electronics industries.
-Fatima Jafri
