Unfortunately, some companies aren't performing any qualification testing at all. Qualification testing can be expensive and time-consuming. After all, being first to market is key. However, without qualification testing, it is impossible to know whether a product is reliable. Qualification testing answers some important questions:

GR-63-CORE, a specification developed by Telcordia, is relatively simple to use. It covers all aspects of physical qual-ification testing for equipment to be installed in an office building or other weather-protected, temperature-controlled location. Included in the specification are temperature extremes of –40° to 70°C for nonoperational storage tests. It also includes an eight-day operating-temperature humidity test profile that runs from –5° to 55°C. Packaging qualification is achieved by the successful completion of transportation, vibration, and handling tests. Other tests include heat dissipation, illumination or readability, altitude, acoustics, contamination, operational sine vibration, and disasters such as fire and earthquake.

GR-63-CORE has two basic test categories: the product must be classified as either a shelf-level product or a frame-level product. A shelf-level product is defined as a chassis or unit designed to be mounted into either a cabinet or an uneven-flange rack. A frame-level product includes a full frame or rack. GR-63-CORE encompasses all of the information needed to perform qualification testing, from test methodologies to test severity levels.

The ETS documents, published by the European Telecommunications Standards Institute, are not as clear-cut as GR-63-CORE. ETS 300 019-X-X includes more than 30 documents under its scope of testing. Although it may appear to be an overwhelming task for a compliance engineer to determine which documents pertain to which tests, a few guidelines can provide some direction.

Unlike GR-63-CORE, the ETS documents specify test se-verity levels only. They do not specify test methodologies. Identifying the appropriate test methodology requires referring to standards issued by the International Electrotechnical Commission. However, the ETS documents are organized in a logical order. A good place to start is with ETS 300 019-1-0, which explains the series and provides an easy-to-follow spreadsheet of other documents.

The documents are divided into seven categories covering in-use installation areas, which GR-63-CORE does not cover. For ease of use, each category is always associated with the same number. For example, ETS 300 019-X-1 always refers to the storage category, ETS 300 019-X-2 always refers to the transportation category, and so forth. This method continues through the installation categories designated stationary in-use weather-protected, stationary non-weather-protected, mobile ground and ship environments, portable nonstationary, and stationary underground.

For this article, only three categories are addressed: storage, transportation, and stationary in-use weather-protected installations. Storage is defined as any time the product is packaged but not in transit, such as sitting on a dock or in a warehouse. Transportation is defined as when the product is in transit from the warehouse to the customer. The final category, stationary in-use weather-protected, refers to when the product is deployed (inside a building or office), protected from the outside elements, and operated while stationary.

In addition, each category has different classes associated with it. The class for each category determines the test severity required for qualification. There are generally three classes for each category. Because the goal is to combine the benefits of GR-63 and ETS 300 testing, it is important to determine which ETSI class to use in the storage, transportation, and in-use categories.

In ETS 300 019-1-1, storage has three classes. Class 1.1 is designed to simulate storage in a partly temperature-controlled, weather-protected area. Class 1.2 simulates equipment storage in a weather-protected area that is not temperature controlled. Class 1.3 recreates storage conditions in a non-weather-protected area with no temperature control. The committee that wrote the ETS specifications recommends Class 1.1. However, using Class 1.2 allows simulating real-life conditions such as non-temperature-controlled trailers. In addition, using Class 1.2 enables the product to qualify as a higher class, because all of the GR-63-CORE requirements are equal to Class 1.2 or higher.

For the transportation category in ETS 300 019-1-2, there are also three classes to choose from: Class 2.1, very careful transportation; Class 2.2, careful transportation; and Class 2.3, public transportation. Needless to say, domestic commercial carriers should not be considered as anything except Class 2.3.

The final category is the operational, or in-use, category. The classes in this category consist of Class 3.1, temperature-controlled location; Class 3.2, partly temperature-controlled location; Class 3.3, not temperature-controlled; Class 3.4, sites with heat traps; and Class 3.5, sheltered location. To be more realistic, choose the higher Class 3.2 in lieu of the recommended Class 3.1.

With categories defined and a suitable class selected for each, the next step is to determine which steps from ETS and GR-63 to combine. Further complicating the process, the vibration and temperature levels overlap in certain areas of the two standards. But combining the two specifications is a relatively easy process.

The levels for storage (Class 1.2) can be found in ETSI EN 300 019-2-1, version 2.1.2, which also provides a list of different tests. Fortunately, only five of the tests are required. The first test required is a low-air-temperature test at –25°C that continues for three days. GR-63-CORE specifies a three-day low-temperature-storage and thermal-shock test requirement of –40°C. Class 1.2 requires a high-air-temperature test of 55°C for three days, whereas the high-temperature and thermal-shock test in GR-63-CORE is 70°C for three days.

Class 1.2 also requires a high-relative-humidity (RH) test for four days at –30°C (93% RH). GR-63 specifies a four-day high- relative-humidity exposure test at –40°C (90–95% RH).

All of the GR-63-CORE tests require specifications that either meet or exceed the requirements for Class 1.2. For the remaining tests in the Class 1.2 requirements, the transportation levels of Curve 2 in GR-63-CORE cover the sine vibration test level. For testing to Class 2.3, public transportation, the relative-humidity condensation test levels exceed those of Class 1.2. Therefore, qualification to this class requires no additional tests.

However, as mentioned earlier, there will be some additional storage tests to run to qualify on the basis of ETS 300 019. Most of the additional tests fall in Class 2.3, transportation. The levels for this category and class can be found in ETS EN 300 019-2-2, version 2.1.2. For the thermal portion of this specification, the GR-63-CORE requirements meet or exceed the low-air-temperature, high-air-temperature, and damp-heat steady-state requirements.

In this category, the only additional environmental test requirements to perform are the air-to-air change-in-temperature test, the rain-intensity test, and the relative-humidity condensation or damp-heat cyclic test, which qualifies for both Class 1.2 and Class 2.3.

Three dynamic tests are required for this class. A random-vibration test is run for 30 minutes in each of the three mutually perpendicular axes at an overall level of 0.8 g rms. A half-sine shock test exposes the product to either a 10-G, 11-millisecond or a 30-G, 6-millisecond pulse, depending upon its weight, 100 times in each of six directions. (Shipping a product on a skid can reduce the 600 pulses down to 100 pulses in one direction of the vertical axis only.) The final test to cover in this category is the free-fall or drop test. This test, specified for Class 2.3, has higher drop heights than the requirements in GR-63-CORE. Class 2.3 requires drops on only the six flat surfaces, whereas GR-63-CORE requires drops on three flat surfaces, three edges, and four corners.

To blend these two tests, drop all six flat surfaces from the higher height requirements of the two specifications and continue with the drop heights from GR-63-CORE for the corners and edges. It should be noted that this drop test is for items that fall into category A of GR-63-CORE. For skidded items, two bottom drops are required for ETS Class 2.3. One bottom drop, two edge drops, and two corner drops are required for GR-63-CORE in category B packages. These tests can be assimilated in the same manner as those for the category A products.

Merging the Class 3.2 in-use stationary location tests is not as straightforward as blending the tests for the other two classes. Initially, the operating-temperature profiles must be combined from both specifications to design a profile (see Figure 1).

Figure 1. Test profile combining test levels of ETS 300 019-2-3, Class 3.2, and GR-63-CORE.

Combining the test procedures provides innumerable benefits to test engineers, and to the bottom line, but it does present a few pitfalls to address. One problem is the in-use sine requirements. The office vibration test for a shelf-level product in GR-63-CORE requires that the test sample be mounted into an uneven-flange, zone 4–qualified frame. ETS, however, requires mounting the sample into a rigid fixture that simulates its in-use mounting configuration.

Another issue is the exposure time. The GR-63-CORE office vibration test is 30 minutes longer than that of the ETS in-use requirement. However, the ETS test levels are higher, and the frequency range extends out to 200 Hz, whereas GR-63-CORE only reaches 100 Hz. In this case, it is simply easier to run the test profiles separately than to calculate the abstract mathematics required to combine the two test curves. An additional benefit to keeping them separate is that ETS also specifies an in-use shock requirement, which requires the same rigid mounting configuration as the in-use sine test.

The last test that requires assimilation is the earthquake requirement from each specification. The zone 4 test curves are the same for GR-63-CORE and ETS 300 019. ETS requires the test sample to be mounted in a rigid test fixture, and GR-63-CORE shelf-level requirements state that the sample must be mounted at the top of an uneven-flange frame.

Extensive research has shown that this difference does not pose a serious problem. To accommodate the difference, use the test setup from GR-63-CORE and place a response accelerometer at the top of the frame near one of the mounting locations of the test sample. The response accelerometer placed at the top of the frame always exceeds the required response spectrum. Simply stated, both requirements can be met with the same mounting system. Furthermore, this fact can be easily proven with test response data.

Where would this leave a company attempting to qualify its product? To meet the requirements of not only GR-63-CORE but also ETS storage Class 1.2, ETS transportation Class 2.3, and stationary in-use weather-protected installation Class 3.2, a company should perform all of the tests as listed in GR-63-CORE, combining the operating-temperature profile and the flat-drop heights from ETS Class 3.2. Finally, adding the air-to-air temperature cycling, damp-heat cyclic, and rain tests from ETS Class 2.3 and the dynamic tests of Class 3.2 completes the combination process.

A total of seven additional tests, taking approximately one week's time, allow a company to save a far greater amount of time in the long run, and they produce a more reliable product. To perform them is certainly a worthwhile investment, because the extra testing opens another continent for marketing.