5.1 Modern offices and other multipurpose buildings commonly have suspended acoustical ceilings installed over room dividing partitions. The test facility prescribed in this test method is useful for providing ceiling attenuation data on the relevant ceiling/partition elements and systems, to ensure that the transmission of sound through the ceiling and plenum space, or through the combination of ceiling, plenum space, and partition systems, provides a suitable degree of acoustical isolation.
5.2 This test method is useful for rating and specifying, under standardized conditions, the sound attenuation performance of ceiling materials when mounted in a specified suspension system.
5.3 This test method may be useful for selecting a wall-ceiling system for probable compliance with a performance specification for overall sound isolation between rooms. However, the actual field performance may differ significantly, particularly if the field plenum depth is not within the limits specified in this test method or if the plenum space contains large ducts, beams, etc., or both. (See Test Method E336.)
5.4 The flexibility inherent in the test facility enables evaluation of the effects of penetrations, induced leakage paths, luminaire, and air diffuser installations and discontinuities in the ceiling suspension system at the partition line, including penetration of the partition into the ceiling plenum. The effect of installing plenum barriers at the partition line may also be investigated.
5.5 With the concentration of sound absorbent area offered by a suspended sound absorbent ceiling installed in a room, it is not possible to obtain a good approximation to a diffuse sound field in that room. The plenum dimensions prevent the maintenance of a diffuse sound field above the test specimen. These factors affect the values of the measured ceiling sound attenuation and thus the measurements are not a fundamental property of the ceiling. The test method measures the acoustical properties attainable under the prescribed test conditions, which have been arbitrarily selected. The conditions must be adhered to in every test facility so that the measured results will be consistent. Two methods for obtaining A, the receiving room absorption, are given without preference. One method, known as the steady state method, has been used to obtain an estimate for A in the AMA 1-II-1967 standard. The other method follows the procedures used in Test Methods E90 and C423; justification for the use of this method may be found in reference (1)5. Persons wishing to further investigate the limitations imposed by this test method are advised to read references (2), (3), (4) and 玻璃安瓿瓶微泄露密封性检测仪测试原理
测试原理玻璃安瓿瓶微泄露密封性检测仪完全符合
ASTM
F2338-09标准和USP40-1207法规要求,基于双传感器技术,双循环系统的真空衰减法原理。将微泄漏密封性测试仪主机连接到一个特别设计用来容纳需要被测试的包装物的测试腔内。... 以中国科学院声学研究所的混响室为例,声学所混响室分为三种:体积为425m³的一号大混响室可做专门研究;体积为191m³二号标准混响室可用作经常性的吸收材料测试;体积为100m³左右的三号小混响室可用于测量墙与天花板的隔声量或一般性测试。混响室的要求:1、加长空室的混响时间;2、保证室内声场的扩散状态。隔声室隔声室可用于测定楼板、墙板、门窗等对结构和空气声的隔声特性。... 满足标准同时满足JGJ106-2014 ,ASTM D6760等多国检测规范的要求。分析方法缺陷分析方法除JGJ106-2014中的统计法外,还提供美国常用的过滤法。全新测试软件CHA-S CHA-S软件可以同时采集4个探头的6组测试数据,并且能够在测试过程中对测试数据进行评估。CHA-S设置更简单,用户在测试前只需在设置中将探头拖动到相应的声测管即可定义探头位置。...图解专业声学检测实验室
用了它,测试时间减少了80%
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