【法规名称】
【法规编号】 79200 什么是编号？
【正 文】
第2页 CAP 400D NOISE CONTROL (HAND HELD PERCUSSIVE BREAKERS) REGULATIONS
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[接上页] 3. DEFINITIONS 3.1 Sound pressure level LpA The sound pressure level LpA is obtained by applying the weighting A to the sound pressure level Lp.The sound pressure level Lp, expressed in dB, of a noise is defined by- Lp=20 log10 P/Po Where- P is the effective sound pressure value measured at a particular point, expressed in Pa; Po is the effective reference sound pressure, equal to 20 x 10-6 Pa. The value LpA of the A-weighted sound pressure level, expressed in dB(A), is obtained by applying the weighting A to the measuring system. 3.2 Measuring surface The measuring surface of area S (see paragraph 8.3) is a hypothetical surface surrounding the sound source and on which the measuring points are arranged (see paragraph 6.4). 3.3 Surface sound pressure level LpAm The surface sound pressure level LpAm is the root mean square of the sound pressures recorded on the measuring surface, calculated in accordance with the method set out in paragraph 8.4. 3.4 Sound power level LWA The sound power level LWA is obtained by applying the weighting A to the sound power level LW. (80 of 1997 s. 102) The sound power level LW, expressed in dB, of a sound source is defined by- LW=10 log10 W/Wo Where- W is the total sound power generated by the sound source, expressed in watts; Wo is the reference sound power, equal to 10-12W. The value LWA of the A-weighted sound power level, expressed in dB, is obtained by applying the weighting A to the measuring system. 3.5 Extraneous noise Extraneous noise means the noise resulting from background noise and parasitic noise. 3.5.1 Background noise Background noise means any noise recorded at the measuring points which is not generated by the appliance. 3.5.2 Parasitic noise Parasitic noise means any noise at the measuring points which is generated by the appliance but not directly radiated by it. 4. CRITERION TO BE USED FOR EXPRESSING RESULTS 4.1 Acoustic criterion for the environment The acoustic criterion for the environment of the appliances is their sound power level. 5. MEASURING INSTRUMENTS 5.1 General The instruments shall be designed to measure the A-weighted level of the root mean square of the sound pressure. The level of the root mean square value in time for a measurement point is obtained either by direct reading of the instrument, or by calculation in accordance with paragraph 11. 5.2 Measuring instruments The following instruments may be used- (a) a sound level meter meeting the requirements of International Electrotechnical Commission (IEC) publication 651:1979 (type 1). The meter shall be set at "slow" response; (b) an integrating sound level meter effecting analog or digital integration of the squared signal over a given time interval meeting the requirements of IEC 804:1985 (type 1). The meter shall be set at "fast" response. 5.3 Microphone with cable Use shall be made of a microphone with cable complying with IEC publication 651:1979, and calibrated for free field measurement. 5.4 Weighting network Use shall be made of an A-weighting network meeting the requirements of IEC publication 651:1979. 5.5 Inspection of the measuring apparatus Before the tests, the acoustic properties of the entire apparatus (measuring instruments including microphone and cable) shall be checked by means of a calibrated sound source with an accuracy of at least 0.5 dB (e.g. a pistonphone); the apparatus shall be checked again immediately after each series of measurements. 6. TEST CONDITIONS 6.1 General 6.1.1 Determining the mass of an appliance When the mass is being determined, the appliance shall be fitted out as for normal use, except for the chisel, the supply tube and, where appropriate, the coupling. 6.1.2 Block characteristics The concrete test block shall be constructed in accordance with Figure 1. 6.2 Operation of the appliance during measurements To ensure that the measurement may be reproduced, all appliances shall be tested in the vertical position. The appliance shall be operated by an operator standing on top of the test block and shall be held firmly down as shown in Figure 2. In the case of pneumatic appliances, the air exhaust axis of the test appliance shall be equidistant from 2 measuring points (air exhausted directly on to a microphone distorts the measurement, which consequently has to be abandoned). The operation of the appliance shall have the same acoustic stability as in normal service and shall satisfy the following requirements- The appliance shall operate at a working pressure of 600 kPa or as specified by the manufacturer. The pressure used shall be indicated in the test report. The appliance shall operate normally; and hindrances to the air exhaust, such as icing up, shall be avoided. In the case of appliances powered other than by compressed air, the operating conditions shall be those corresponding to the maximum speed at which the appliance can operate continuously, according to the manufacturer's statement. |
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