The California Noise Insulation Standards have been in effect for about two years. This unique piece of legislation has for the first time placed minimum requirements for noise insulation within all building codes in the state. Many such modifications of the building code takes time to filter down to the local governments. Lacking the acoustical expertise, local governments have varying responses to the Noise Insulation Code and varying approaches to responsibility for imposing requirements. One result of the rode has been stricter reviews of current practices in constructing party walls and floor-ceiling assemblies in the field. This has revealed many difficulties in current designs and most particularly in practices in the building industry for the installation of such assemblies. This paper will address the experience of Bio-Acoustical Engineering Corp. as a consultant to builders and local building officials on this issue in over 500 different separate reports in the last two years. Some recommendations on the implementation of the code will be included.

The Del Mar Fairgrounds, San Diego, hosted the IMSA Grand Prix for 6 years from 1987–1993. The project provides a unique long-term study of professional road racing noise in a unique setting, a narrow valley just east of the coastline and within an environmentally sensitive lagoon. Sponsors were required to perform community noise monitoring at selected locations in the adjacent hills and lagoon. Both human and bird responses were examined. The monitoring documented the hour by hour variations in the maximum and average noise levels at up to 12 separate locations. The results indicated the thresholds which would trigger community response, the sensitivity of the response to diurnal and short-term wind shift, the effect of the inversion layer, the effects on bird patterns, and the statistical distribution of vehicle noise levels for the IMSA class vehicle. Basic findings revealed community response was triggered when levels exceeded 70 dBA Lavg. Downwind levels tended to increase at 1 dBA/mph over 5 mph. When the track was within an inversion, levels increased 10 dBA. The mean vehicle level at 15 m was 105 dBA with a 4-dBA standard deviation.

The California Noise Insulation Standards has for the first time imposed STC testing on a broad segment of the building industry. Local officials and builders, its well as consultants, find it increasingly burdensome to implement standard STC (ASTM) field testing because of costs and delays. Inspectors are reluctant to require testing because of the costs and delays, yet there seems to be no easy alternative available. This paper discusses the results of over 100 tests conducted in the Southern California area of party walls with the object of considering whether a screening method for party-wall checks can be used as a viable alternative to the ASTM method in field inspections. The paper will propose a possible technique for adoption as a supplement to ASTM methods currently employed.

Pomona International Raceway, Pomona, California is the premier venue for drag racing sanctioned by the National Hot Rod Association. Community noise was studied for 9 years from 1984–1993. The project provided a unique long-term study of professional drag racing noise at 14 locations in a built-up community adjacent to the starting line. The object was to establish a basis for documenting the effects of noise mitigation’s planned for a renovated facility. The study revealed startling diurnal variations in noise, year to year variations, and the wide variety of emission characteristics of racing types. The simultaneous community and trackside locations permitted accurate correlation of events and established the basis for predictive models. The large data base permitted creation of a benchmark location by which the construction mitigation measures could be verified in a statistically valid manner. The study also revealed that the data spread is so wide that only multiple event sampling will provide an accurate picture of the community noise levels.

A five-station, permanent, 24-h centralized aircraft noise monitoring system has been installed in the community surrounding Orange County Airport, Santa Ana, California. This paper will discuss the design concept, the results obtained from initial tests involving measurement of over 1000 flights, the practical experience gained from the installation, the true value to the community, and the potential for effective noise management programs. In addition, the measurement data will be used to demonstrate the value of the California noise index CNEL.