THE SCIENCE AND APPLICATIONS OF ACOUSTICS - H. H. Arnold ...

13.12 Guidelines and Regulations in the United States 347not be exposed to more than A-weighted L eq = 85 dB per 8-h day. This value isdetermined from measurements made at the position occupied by a worker’s earsduring work, preferably in that person’s absence, using a technique that minimizesthe effect on the sound field. If the microphone has to be located close to theworker’s body, appropriate adjustments should be made to determine an equivalentundisturbed field pressure. The daily personal noise exposure does not take intoaccount the effect of any personal ear protectors used. Should the allowable dailyexposure be exceeded, the affected workers are to be notified, and proceduresmust be enacted to lower the exposure, which may include periodic checks ofthe work environment, provision of ear protectors, and audiology tests. If thedaily personal noise exposure exceeds 90 dB(A) or the maximum value of theunweighted instantaneous sound pressure is greater than 200 Pa, the employermust exert every effort to cut down this exposure.Vehicle Noise RegulationsExterior noise tests for road vehicles have been used in Japan since 1971. Thecurrent version of the tests is quite thorough and consists of three parts: (a) a fixedpassby test at 7 m, 60% rated engine speed or 65 km/h, (b) an acceleration passbytest at 7.5 m, and (c) a stationary test behind the exhaust outlet at 20 m.In these tests the microphone is placed 1.2 m above ground level. The noiselimits for new highway vehicles are given in Table 13.6 which went into effect in1998. Another 2 dB reduction in these noise limits has been in effect since 2002.Table 13.7 lists the mandatory exterior limits for new highway vehicles sold inthe European Union. The EU vehicle noise test procedure is prescribed in CouncilDirectives 92/97 EEC and 81/334/EEC, presented in the Official Journal ofthe European Communities. Amendments were added for automatic transmissionequippedand for high-powered vehicles. The test is based on ISO 362, which issubstantially equivalent to SAEJ140 (cf., Handbook of the Society of AutomotiveEngineers). A 1-dB(A) tolerance is permitted in this test. The test and its derivativesTable 13.6. Japanese Noise Limits for New Highway Vehicles.VehicleDescription GVWR (metric tons) Power (kW) Limit [dB (A)]Passenger car — — 76Light truck 3.5 >150 81Moped 50 cc < 125 cc 70>125 cc < 250 cc 73>250 cc 76