Equivalent Values of Traffic, Aircraft and Industrial Noise.
Abstract
Equivalent values of traffic, aircraft and industrial noise, as rated by the separate indices L sub 10 (18 hour), Noise and Number Index (NNI), and Corrected Noise Level (CNL) respectively, are derived by a translation method which uses L sub eq and L sub NP as intermediate measures. The value of NNI numerically equivalent to a particular value of L sub 10 as derived by the L sub eq translation differs by approximately 10 units from that derived by the L sub NP translation. The origins of this numerical difference are outlined and the implications discussed. Evidence is presented which suggests that L sub NP is the more appropriate measure to use in equating levels of separate indices in terms of acceptability. The result of the translation from L sub 10 to NNI using L sub NP confirms the implied equivalence between the traffic and aircraft noise criteria recommended in the Department of the Environment Circular 10/73, 'Planning and Noise', within the tolerance imposed by the limitations of the respective descriptors. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1974
- Accession Number
- ADA085009
Entities
People
- B. F. Berry
Organizations
- National Physical Laboratory