Humidity heat test

A test specimen is subjected to elevated temperature and relative humidity over a certain period of time. The parameters frequently used in practice for MID have temperature set to +85 °C and 85% relative humidity for this test. The thermoplastic substrates absorb water under these conditions, so the test enables insulating properties to be checked along with corrosion of the plating. Humidity heat testing is frequently followed up by an extra test of the metallization s adhesion. 

In addition to the temperature-shock and humidity heat tests common in MID engineering, but with degrees of severity adapted to the automotive application, the project also included steady-state high-temperature tests at 125 and 150 °C. The samples were also subjected to mechanical loading in vibration tests, partly because the high proportions of fillers in the plastics were expected to cause reduced adhesion of the metallization. Supplementing the numerous tests for plastics char-... 

If it is variable, set the outside air intake quantity to the winter value. Set the desired temperature up to a maximum, leaving the humidity setting alone. It will be appreciated that as the room temperature rises during the heating test the rh tends to fall. However, since the humidity setting remains unaltered the humidifying system will be called upon to operate until at one condition it is working at peak winter rate. Due to the faster characteristic of heaters, the rh will be found to fall but absolute moisture should be found to steadily rise. The duration of the test is normally about 3 h and final conditions should be held for half an hour to prove the moisture source. 

There are different heat tests, some being specific to a product environment. There are those for temperature and also humidity. With certain materials, humidity combined with elevated temperatures has a significant effect on the material s behavior. This effect would not be evident in the conventional heat distortion test (HDT). 

The damp heat test can be made under steady state conditions when 40 °C and 93% relative humidity (RH) are specified, or under dynamic conditions when the temperature is cycled from 25 °C to 40 °C or 55 °C. Clearly, other conditions could be chosen to suit the application. 

Finally, considering that, in general, ZnO is known to be particularly sensitive to a humid environment (see paragraph 9.4.1.2), this feature should also be checked, in more detail, for the case of ZnO films deposited by CVD. In fact, Sang et al. [84] reported that in a humid environment, ZnO B films deposited by LP-CVD showed higher degradation than sputtered ZnO Ga films. On the other hand, Oerlikon Solar (formerly Unaxis Solar) [79] has proven that thin him silicon solar modules using LP-CVD ZnO as TCO layers can successfully pass the standard damp-heat test, provided they are encapsulated in an appropriate manner. 

Reliable stability data of the p-i-n solar cell itself are not easily obtained, especially for non-encapsulated cells or modules. One of these tests e.g. for EN/IEC 61646 certification of modules is the so-called damp-heat test (85°C, 85% humidity, up to lOOOh). Recent studies were performed by Stiebig et al. [50, 51] exposing different types of cells to harsh conditions. One of the most important results was the excellent stability of silicon thin film solar cells. Remarkably, this is also valid for small area modules even without encapsulation [52]. This is of high interest because costs and efforts for module encapsulation strongly depend on the inherent stability of the solar cells. As a more detailed treatment of this subject is beyond the scope of this chapter, the reader is referred to the original papers [50,51]. 

When reporting on dry-heat test data, relative humidity is measured and controlled instead of water activity. This is because of the fact that biological materials more closely parallel vapor pressure than water content, and vapor pressure of the gas atmosphere surrounding dry microbial cells is more easily measured and controlled than the water content inside the cell. ... 

Nitroindene polymer was obtained by the nitration of polyindene (31- It is an amorphous solid of m.p. 230 0, and is insoluble in most solvents. Decomposition (explosion) temperature is above 360 C. It is sliglitly hygroscopic, taking 1.61% w ater from the atmosphere of 100% relative humidity. The Inler-nationaJ heat test at 75 C showed 1.1% loss of weight. A sample of 5 g evolved in vacuo 2 cm of gas in 48 hours. It was considered for use in U.S.. Army as a time fuse but was found to be too sensitive to impact. 

Stability testing is a technical experiment conducted at well-defined conditions, for example at fixed temperatures and humidities. These testing conditions provide a model for the climatic conditions in the environment in which the drug substance or medicinal product is stored and shipped during shelf-life. This environment can be sufficiently described by parameters influencing the stability, mainly heat and... 

In the damp heat test, the test pieces are subjected either to static temperature and humidity conditions of 40"C at 93% relative humidity or to 12-1- 12 hour cycling between 23" C at >95% relative humidity and 40 C (or 55 C) at 93% relative humidity. For the water spray test a mist of distilled water at 40 C is sprayed over the surface of the plastic at the rate of 125 to 250 ml per hour per square meter of surface, while for the salt spray test... 

Properties of coated fabrics can alter or change with exposure to humidity, heat. cold, fatigue, and chemicals, and tests have been devised to simulate these conditions and monitor behavior. 

In order to demonstrate that HER compared to butanediol-based elastomer has better physical and mechanical properties at elevated temperatures, cast elastomers with 95% stoichiometry have been made from an MDI terminated polyester prepolymer (Baytec MS-242) extended with butanediol and HER-HP (from INDSPEC Chemical Corporation). Test specimens were cut from a sheet post cured at 110 °C for 16 hours, for the tensile, tear, DSC and DMA determinations. In the preparation of material for the dry heat aging evaluation, tensile, DSC and DMA samples were placed in an air oven with the temperature controlled within 2 °C of the set point and aged for 28 days at 100 °C, 21 days at 120 °C and 14 days at 135 °C. Then, all the samples were stored for at least seven days at room temperature and 50% relative humidity before testing. 

High temperature/high humidity bias test and storage test, JIS C 7022, B-5 lEC PUB 68 Test C (heat test, MIL-STD-750, method 2031 ... 

The goal of the backsheet is to provide UV and moisture protection, electrical insulation, and durability. To this purpose, standard international committees (such as lEC and UL) have defined a set of tests to be passed before a photovoltaic s module could be placed on the market. The lEC 61215 is one of the most used standards for qualifying a PV module [7]. The aim of these tests is to check the resistance of the PV module to all the variables that can affect and infiuence the life of the module itself such as electrical performance, hail and impact test, weathering, and temperature (UV and thermal cycling). One of the most important tests is the damp heat test, 1000 hours inside a climatic chamber at 85°C and 85% relative humidity. Most of the PV module producers tend to prolong well above 1000 hours of damp heat, to be sure that the module will survive after 25 years giving at least 80% of the initial power. This trend is also taken into consideration into the new version of the standard tests that is considering to have at least 2000 hours of damp heat for qualification. 

Fig. 13.10 Results of FEM simulations of the humidity in PV modules in the encapsulant. Left diagram in front of the impermeable silicon cell (Pos 4 in the inset to the right) calculated with real monitored climatic border conditions at different locations with periodic repletion of one-year data of weathering. Right diagram during an extended damp-heat testing for 3000 h at 85 °C and 85 % relative humidity at different places in the PV module 1 is between the permeable back-sheet, 2 in the gap between two cells, 3 at halfway between edge and centre of a cell, 4 at the centre of the cell...

The stability of TMETN is not very satisfactory as indicated by the vacuum stability and heat tests. In the 100°C heat test, a 2.5 percent weight loss is reported in the first 48 hours and 1.8 percent in the second 48 hours. No explosions occur in the first 100 hours. In the 100°C vacuum stability test, 1.9 cubic centimeters of gas are evolved in the first 40 hours. At 25 C TMETN is hygroscopic to the extent of 0.07 percent with 90 percent relative humidity and 0.14 percent at 100 percent relative humidity. 

The 150°C vacuum stability test indicates HMX is comparable to TNT in stability, with test values of 0.6 and 2.5 milliliters of gas evolved. The 100°C heat test loss in the first 48 hours is 0.05 percent and in the second 48 hours 0.03 percent. No explosions occur in 100 hours. At 30°C and 95 percent relative humidity, HMX is nonhygroscopic. In the LLNL reactivity test, less than 0.01 cubic centimeters of gas are evolved. The... 

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