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ISO 19862-2015 pdf free download
ISO 19862-2015 pdf free download.Buildings and civil engineering works Sealants Durability to extension compression cycling under accelerated weathering
Bâtiments et ouvruges (legenie civil — Mustics — Durubilité (I un cycle d ‘extension -compression du ns des conditions de vielilissem en t uccéléré.
5.10 Fully automated artificial weathering test chamber with an artilicial light source, fully automated test chamber with an artificial light source (see Ill), shall he used. capable of exposing the test spt’cimlwns to radiation under controlled conditions of temperature, relative humidity, and watel; complying with the requirements of ISO 4892—1. ISO 4892—2, ISO 41192—3. and ISO 4892-4. The radiation is always directed towards the same surface of the sealant specimen. Standard practices for operating such accelerated weathering chambers are described in ISO 4892-I.
The level of irr.mdiance and water exposure at the specimen surface may not be altered.
In fully automated test equipment, exposure to water for this test method is accomplished by water spraying the specimen surface or immersing the test specimens in water (see Note 1 and Note 2). Contamination of the water is to he avoided. The purity of the water to be used is described in ISo 4892-1. The water temperatures are typically (21 ± 5) °C for the spray water and typically (40 ± 5) nC for the re—circulated immersion water (see Note 3).
Suitable equipment and test procedures for cyclic exposures to water are described in ISO 4892-1, ISO 4892-2, ISO 4892-3, and ISO 4892.4. Water is a key factor contributing to the ageing of sealants, especially in combination with exposure to light. In xenon arc devices that use water spray for wetting. relative humidity during the light period shall be maintained at (SO ± 10) % Rh, (see ISO 4892-2:2013, Table 3, Method A, Cycle Number 1) (see Note 4).
In the immersion technique, the test specimens arc placed in a chamber that is periodically flooded with re-circulated water. During immersion, the specimens are completely covered by water. The water temperature is measured below the water surface with the black standard thermometer. The immersion spray water can he at a higher temperature. The uncontrolled temperature of the recirculated immersion water during operation of the weathering device is typically (40 ± 5) GC. It can be controlled by heating the water to a Ii igher temperature. however, heating is not desirable because the water immersion temperature would then (litter to a larger extent from the spray water temperature,
NOTI I Adequate heat transfer between the test specimen and the environment is essential during the lower temperature period in the fluorescent IJV/condensatmon device in order [or condensation on the sealant to occur. This l)Iaces restrictions on the thermal niass and, consequently, tjn the dimensions of a specimen. No (J)erimental data have heeii generated on the time-of-wetness of sealant test specimens oft he kind specified in this International Standard when placed in fluorescent IIV/condensation device operating at conditions specified in this International Standard. Ilowever. testing conducted by ASTM C24 on ISO 8339 specimens appears to suggest that the condensation process provided in the fluorescent (IV/condensation apparatus is generally not applicable to the type of sealant specimens tested. Therefore, wetting in this International Standard is carried out by water spray on the exposed specimen surface (delimIt method). However, the front surface water spray accessory was not designed for this purpose and requires an unreasonable amount of ptii’t’ water for the wet period specified. Therefore, often the equipment is modified to allow re-circulation of the water during the exposure pi’riod. Some fluorescent LIV equipment have adaptable spray manifolds, which allow installation of lower flow type nozzles, thus reducing the amount of pure waler used.ISO 19862-2015 pdf free download.
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