The standard families that govern temperature and humidity testing cover different products, and their method numbers are not interchangeable. The same physical stress is written with a different purpose, specimen condition, severity selection and acceptance requirement in each one. Matching the requirement to the right standard is the first step; only then does the chamber specification make sense.
What each family governs
| Standard family | Scope | Representative methods |
|---|---|---|
| GB/T 2423 series | Environmental testing of electric and electronic products | GB/T 2423.3 damp heat |
| GJB 150 series | Environmental testing of military equipment | GJB150.3 high temperature, GJB150.5A temperature shock |
| IEC 60068 | International environmental test methods | −2-1 cold, −2-2 dry heat, −2-14 temperature change, −2-30 damp heat, −2-13 low air pressure, −3-5 chamber performance |
| MIL-STD-810 | US military environmental engineering and testing | Method 501.7 high temperature, 502.7 low temperature, 503.7 temperature shock, 500 low pressure |
| JEDEC JESD22 | Semiconductor reliability | JESD22-A104 temperature cycling, A101 THB, A118 UHAST |
Choosing between them
- General product and electronic environmental testing: IEC 60068 with the corresponding GB/T 2423 part.
- Military equipment and defence programmes: GJB 150, or MIL-STD-810.
- Airborne equipment: RTCA DO-160.
- Automotive electronics: ISO 16750 and AEC-Q100, with GB/T 28046.4 and GB/T 10485 used in some programmes.
- Semiconductor devices: JEDEC JESD22.
How the standard drives the chamber
What the standard fixes is the condition the chamber has to reproduce: temperature range, humidity, ramp rate, pressure and tolerance. A temperature shock requirement such as GJB150.5A or MIL-STD-810H Method 503.7 points to a thermal shock chamber. A moisture-and-bias requirement such as JESD22-A101 THB or JESD22-A118 UHAST points to a temperature-humidity chamber with a bias interface and stable long-duration control. Fix the standard and the method number first; the chamber follows.
A note on humidity tolerance
Humidity test chambers are specified with humidity uniformity of ±1.0% RH and a relative humidity deviation of ≤ ±3.0% RH above 75% RH and ≤ ±5.0% RH at or below. Different standards set different severities and acceptance criteria, so the tolerance quoted has to be read against the standard, not against a general figure.
The method number comes first
Identify the standard and the specific method, then translate it into a chamber requirement. If you are not certain which family applies to your product, contact us with the product type and the intended market and we will point to the usual standard and the chamber configuration it implies.
Two questions that come up
Which chamber for a moisture-and-bias test? JESD22-A101 THB and JESD22-A118 UHAST apply temperature and humidity together with electrical bias, so the chamber needs a bias interface and control that stays stable over a long run, not just a humidity setpoint.
Who verifies that the chamber itself is good enough? IEC 60068-3-5 gives the method for verifying a temperature chamber’s performance, which is separate from the test the chamber is used for.