定价： 481元 / 折扣价： 409 元 加购物车

定价： 260元 / 折扣价： 221 元 加购物车

定价： 481元 / 折扣价： 409 元 加购物车

4.1 The purpose of the LIR rating is to describe the low-frequency impact noise, often referred to as “thudding,” primarily generated by footfall on lightweight structures. The rating increases as the impact sound attenuation of the floor-ceiling structure increases. This rating has been shown to correlate with subjective reaction3,4 and can be used to evaluate and compare the low-frequency impact noise performance of assemblies.4.2 The LIIC rating can be used for relative comparison and to rank-order the low-frequency performance of assemblies within a given test laboratory.5 The reproducibility of LIIC between laboratories has not been measured, and the relationship between laboratory and field ratings (LIIC and LIR) is not assumed or established.NOTE 1: The tendency for measurement uncertainty to increase at low frequencies should be considered when utilizing metrics of classification standard.NOTE 2: This classification does not replace Classification E989 (Impact Insulation Class) and is not interchangeable with it. For example, the LIIC rating of an assembly does not determine its IIC rating and cannot be used to show compliance with an IIC requirement. The expectation is that the low-frequency ratings would be reported alongside the existing ratings.4.3 This classification shall only be used with one-third-octave-band data.1.1 This classification provides methods for calculating single-number ratings of low-frequency impact noise transmission, based on one-third-octave-band impact noise levels as described in Test Methods E492 and E1007.1.2 This classification defines ratings that are not defined in other standards. Other standards may define additional ratings based on the methods of this classification.1.3 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 515元 / 折扣价： 438 元 加购物车

5.1 This practice gives an objective measure of the temperature sensitivity of a thermal imaging system (relative to a standard reference filter) exclusive of a monitor, with emphasis on the detector(s) and preamplifier.NOTE 1: Test values obtained under idealized laboratory conditions may or may not correlate directly with service performance.5.2 This practice affords a convenient means for periodically monitoring the performance of a given thermal imaging system.5.3 NETD relates to minimum resolvable temperature difference as described in Practice E1213. Thus, an increase in NETD may be manifest as a loss of detail in imagery.5.4 Intercomparisons based solely on NETD figures may be misleading.NOTE 2: NETD depends on various factors such as spectral bandwidth and background temperature.1.1 This practice covers the determination of the noise equivalent temperature difference (NETD; NEΔT) of thermal imaging systems of the conventional forward-looking infrared (FLIR) or other types that utilize an optical-mechanical scanner; it does not include charge-coupled devices or pyroelectric vidicons.1.2 Parts of this practice have been formulated under the assumption of a photonic detector(s) at a standard background temperature of 295 °K (22 °C). Besides nonuniformity, examinations made at other background temperatures may result in impairment of precision and bias.1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 515元 / 折扣价： 438 元 加购物车

3.1 Resistance or voltage values alone do not provide sufficient detail for an engineering evaluation of contact noise. This practice lists the test conditions that should be reported with noise measurements and indicates some conditions (open circuit voltages, currents, etc.) that have been used for quality control and research studies. The use of these practices should provide sufficient detail for an engineering interpretation of the noise data and allow the tests to be repeated by another laboratory.1.1 This practice describes the practices and factors considered to be most important in the measurement of electrical contact noise of sliding contacts.1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to become familiar with all hazards including those identified in the appropriate Safety Data Sheet (SDS) for this product/material as provided by the manufacturer, to establish appropriate safety, health, and environmental practices, and determine the applicability of regulatory limitations prior to use.1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 515元 / 折扣价： 438 元 加购物车

定价： 345元 / 折扣价： 294 元 加购物车

定价： 345元 / 折扣价： 294 元 加购物车

定价： 260元 / 折扣价： 221 元 加购物车

定价： 345元 / 折扣价： 294 元 加购物车

定价： 481元 / 折扣价： 409 元 加购物车

定价： 481元 / 折扣价： 409 元 加购物车

定价： 384元 / 折扣价： 327 元 加购物车

5.1 The noise reduction of an enclosure is a property of the enclosure, the location of the sound source used to measure noise reduction, and the space in which the enclosure is placed. It is not a property of the enclosure alone, and its measurement under different conditions can be expected to give different results. When the noise reduction is measured in accordance with this test method, the sound source is outside the enclosure and the sound field outside the enclosure approximates a diffuse sound field. Measurements made in accordance with this test method can be expected to be reproducible from one laboratory to another.5.2 The noise reduction measured in accordance with this test method may be used for the following purposes:5.2.1 To rank the order of sound-isolating enclosures according to noise isolation class, NIC.5.2.2 To estimate the highest one-third octave band sound pressure levels that can occur outside the enclosure without exceeding specified sound pressure levels inside the enclosure.5.2.3 To estimate the one-third octave band sound pressure levels that will occur inside the enclosure with specified sound pressure levels outside.5.3 The noise reduction measured in accordance with this test method may not estimate accurately the isolation that the enclosure will provide when it is used to isolate a noise source inside it from the space outside. The user should be cautious when using noise reductions measured by this test method to evaluate enclosures used to enclose noise sources.5.4 Sound-isolating enclosures are frequently made from prefabricated modular panels. The noise reduction measured by this test method applies to the complete enclosure and not to individual panels from which it is made and cannot be used to infer the sound transmission loss of the individual panels.5.5 Specifications for sound-isolating enclosures may include reference to noise reduction and noise isolation class measured in accordance with this test method.1.1 This test method covers the reverberation room measurement of the noise reduction of sound-isolating enclosures.1.2 The noise isolation class may be determined from the noise reduction measured in accordance with this test method.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 590元 / 折扣价： 502 元 加购物车

定价： 481元 / 折扣价： 409 元 加购物车