משמעות ושימוש
4.1 The significance of these test methods lies in the ability to distinguish the degree of ozone resistance under limited and specific conditions of accelerated testing. The degree of resistance is judged by the appearance and size of cracks formed on the surface of the material under test.
4.2 In use, rubber materials deteriorate when exposed to ozone. There needs to be a test method in which simple, accelerated time/exposure, comparing the ability of the material to resist cracking caused by ozone exposure, can be evaluated empirically. Such tests can be used for producer/consumer acceptance, adjudication purposes, research and development.
4.3 These methods are not necessarily suitable for use in purchase specifications as the actual conditions of service (outdoor exposure) vary by geographic location and may not produce repeatable or reproducible results and therefore may not have a correlation with service performance.
ASTM D1149-2018 Standard Test Method for Rubber Breakage and Cracking in Ozone-Controlled Environments
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1.1 These test methods are used to estimate the effects of exposure on vulcanized rubber, rubber compounds, moulded or extruded soft rubber and other specified materials under surface tensile strain conditions, dynamically or statically, in an atmosphere containing specified ozone concentration levels expressed as partial pressure (see note 1), or as determined by experience. Excludes the effects of naturally occurring sunlight or artificial light sources.
1.2 Previously published ASTM documentation test method D518 and test method D3395 were included in these test methods D1149 in 2007. See note 2.
1.2.1 Test method D518 and test method D3395 have since been withdrawn and replaced by test method D1149. When referring to or otherwise referring to test method D1149, a symbol to that effect shall be included. See Section 3.2 for appropriate references.
1.3 Specific conditions of exposure to ozone in a controlled environment accelerate compared to outdoor exposure. These accelerated ozone testing methods may not give results relevant to outdoor exposure testing or service performance.
ASTM D1149-2018 Standard Test Method for Rubber Breakage and Cracking in Ozone-Controlled Environments
1.4 All materials, instruments or equipment used to determine mass, force, גודל, ozone concentration, partial pressure, טֶמפֶּרָטוּרָה, velocity and gas exchange rate shall be traced directly to the National Institute of Standards and Technology or other internationally recognized organizations of a parallel nature.
1.5 Values expressed in SI units shall be treated as standard values. הערכים המופיעים בסוגריים הם לעיון בלבד. Many of the SI units described were directly converted from the U.S. customary system to accommodate instruments, practices, and procedures that existed prior to the Metric Conversion Act of 1975.
1.6 This standard relates to hazardous substances, in particular ozone. It can also involve dangerous operations and equipment. This standard is not intended to address all safety concerns, אם בכלל, הקשורים לשימוש בו. באחריות המשתמשים בתקן זה לבסס בטיחות מתאימה, שיטות בריאות וסביבתיות ולקבוע את תחולתן של הגבלות רגולטוריות לפני השימוש.
הערה 1: A discussion and explanation of the measurement of ozone concentration based on the ozone component and partial pressure per unit of air is provided in test method D4575, especially in appendices X1 and X2. Test method D4575 is also recommended as a source of background information for standards involving materials exposed to ozone.
1.7 This international standard is based on internationally recognized standardization principles established in the Decision on Principles for the Development of International Standards, הנחיות והמלצות שהונפקו על ידי הוועדה בנושא חסמים טכניים לסחר של ארגון הסחר העולמי.