BS EN ISO 4611:2010 pdf download

BS EN ISO 4611:2010 pdf download.Plastics -Determination of the effects of exposure to damp heat, water spray and salt mist(ISO 4611:2010).
4.2 Exposure conditions
4.2.1 Damp heat
4.2.1.1 General
The preferred exposure conditions correspond to those described In the IEC publications referred to in 42,1.2 and 42.1.3. Different temperature and/or humidity conditions may be used, however, If specified In the relevant product specifications or by agreement between the interested parties.
4.2.1.2 Steady state test
Unless otherwise specified, the chamber shal be at ambient laboratory temperature and humidity at the start of the test. Place the conditioned specimens (see 4.3.1) in the chamber and adjust the controls to produce the following conditions:
temperature: 401 C:
relative humidity: 93 %.
As the chamber temperature is increasing to 40 C. the rate of temperature change shall not exceed 1 C!min. averaged over a period of not more than 5 mm. During the heating-up period, condensation shall not occur on the specimens.
Once the specified temperature is reached, adjust the relative humidity to the specified level within no more than 2 h
The period ol exposure shall be as specified by the specification covering the material or product being tested When not specified, this period shall be agreed upon by the interested parties. Recommended periods of exposure are 12 h, 16 h, 24 h. 48 h, 96 hand 240 h.
NOTE The conditions given In this subclause correspond to those specified In IEC 60068.2.78:2001
4.2.1.3 Cyclic test
This test takes the chamber and specimens through a number of 24 h cycles during which the temperature shall be maintained at an upper value and at (25±3) C. One of the following two temperatures shall be chosen as the upper temperature:
a) (40 t 1) C (wi which case the number of cycles shall be 2,6, 12.21 or 56);
b) (55± 1)C (in which case the numberof cycles shall be 1, 2or6).
The upper temperature shall be readied within the first 3 h ± 30 mm of each 24 h cycle. Dunng this temperature increase, the relative humidity shall not drop below 95 %. except during the last 15 mm when the relative humidity may drop below 95 % but not below 90 %. Dunng the temperature increase, condensation on the specimens is allowed.
In the following hours, the temperature shall be maintained at the upper value chosen and the relative humidity shall be maintained at (93 ± 4) %.
After 12 h of the 24 h cycle, the temperature shall be allowed to decrease, within 3 Ii to 6 h, to the lower temperature of (25 ± 3) C. During this temperature decrease, the relative humidity shall not drop below 80 %.
For the rest of the 24 h cycle, the temperature shal be maintained at (25 ± 3) C and the relative humidity shall not be less than 95%.
NOTE I The conditions given in this sttdause correspond to those specified in IEC 60068-2-30:2005 (using vaflant 2 for the temperature decrease part of the cycle).
NOTE 2 For composite lemperature/humicMy cycles, with the addition of a number of excursions to sub-zero temperalwes, guidance can be found in IEC 60068-2-38
4.2.2 Water spray
The main difference between this exposure condition and that for damp heatlsteady state (see 42.12) is the constant presence of the liquid phase, in the form of small water droplets.
Suitable equipment for obtaining these conditions is substantially identical to that for the salt mist exposure (see 4.2-3) and Is described in the relevant specifications.
Distilled or deionized water, having a pH between 6 and 7. shall be used instead of the salt solution.
The temperature in the test enclosure shall be (40 ± 2) ‘C.
4.2.3 Salt mist
Dissolve a sufficaent mass of sodium chloride in distilled or deionized water with a conductivity not higher than 20 p51cm at (25±2) C to produce a concentration of (50 ± 5) gil. The specific-gravity range for a (50 ± 5) g/l solution is 1029 to 1,036 at 25 C.
The sodium c.lilohde shalt contain less than 0.001 % by mass of copper and less than 0,001 % by mass of nickel, as determined by atomic absorption spectrophotometry or another analytical method of similar sensitivity. It shall not contain more than 0.1 % by mass of sodium iodide or more than 0,5 % by mass of total impurities, calculated with respect to the dry salt
Adjust lhe pH of the salt solution so that the pH of the salt mist collected in the chamber (see below) is between 6.5 and 7,2 at (25 ±2) C. Check the pH by electrometnc measurement or, for routine checks, using short-range pH paper which can be read In increments or 0.3 pH-units or less. Make any necessary correction by adding hydrochlonc acid, sodium hydroxide or sodium bicartonate solution prepared from analytical-grade reagents.