4.1 Weathering is an inherently variable science because weather itself is variable. Bukod pa rito, even if all devices run the same exposure cycle, results from manually accelerated tests may vary. Kaya nga, all factors need to be controlled as much as possible to reduce the overall source of error.

4.2 Proper handling of samples is important to maintain the integrity of the material being evaluated. Damage to specimens due to improper handling and labeling can adversely affect the effectiveness of test procedures, resulting in loss of money and time. Improper handling can introduce non-standard procedures into the scheme, which can be a significant source of variability, adversely affecting the overall accuracy of the results obtained. Improper processing may also introduce bias in the obtained results.

4.3 The material will change even under seemingly benign conditioning conditions, especially if the sample has been exposed. Kaya nga, it is necessary to minimize the number and length of non-test periods so that exposure is a cause for further changes.

ASTM G147-2017 Standard Practice for Condition Regulation and Handling of Non-Metallic Materials for Natural and Artificial Climatic Testing

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1.1 This practice covers sample preparation, identification, packaging, transportation, handling and conditioning before, during and after natural and artificial aging tests.

1.2 This practice includes detailed information on the conditioning of specimens after exposure and before examination. This practice also includes long-term storage of sample files.

1.3 Regulation in this practice does not refer to the specific act of exposing the specimen to weathering factors.

1.4 Ang pamantayang ito ay hindi nilayon upang matugunan ang lahat ng mga alalahanin sa kaligtasan, kung meron man, na nauugnay sa paggamit nito. Responsibilidad ng mga gumagamit ng pamantayang ito na magtatag ng angkop na mga kasanayan sa kaligtasan at kalusugan at upang matukoy ang pagiging angkop ng mga paghihigpit sa regulasyon bago gamitin.

ASTM G147-2017 Standard Practice for Condition Regulation and Handling of Non-Metallic Materials for Natural and Artificial Climatic Testing

Tala 1: There is no equivalent ISO standard describing procedures for the identification, transport, conditioning and handling of specimens used for natural or artificial ageing tests. ISO 139 at ISO 291 describe procedures for adjusting specimens before and during physical performance tests.

1.5 Ang internasyonal na pamantayang ito ay batay sa mga prinsipyo ng standardisasyon na kinikilala ng internasyonal na itinatag sa Desisyon sa mga Prinsipyo para sa Pag unlad ng mga Internasyonal na Pamantayan, Mga Patnubay at Rekomendasyon na inilabas ng WTO Committee on Technical Barriers to Trade.