December 18, 1967, was a red-letter day in the American noise abatement movement. The locale was the side of the reflecting pool at that citadel of culture, Lincoln Center for the Performing Arts. The invited guests were important enough—two Congressmen (Theodore Kupferman and William F. Ryan), representatives from the Mayor's office and his task force on noise control, representatives of American manufacturers of pneumatic construction equipment, and members of the press. The star of the occasion was a yellow two-wheeled contraption imported from England, something never before publicly demonstrated in the United States, and not being manufactured here: a silenced portable air compressor. Thanks to the English business contacts of Anthony Essex Potter, CQC Board Member, and a British construction equipment manufacturer, Holman Bros., CQC was able to inform the American public that unmuffled construction noise was not necessary.
Several months later, Ingersoll-Rand announced a quieter American two-wheeled compressor, and then topped this with the marketing of a silenced giant four-wheeled compressor (900 cfm) that generated 85 decibels at 1 meter, instead of 105 decibels. Thus was started a gradual move to introduce a degree of quiet design into pneumatic construction equipment. It is taking more than five years of my life, but the days of raw, uncontrolled construction noise are numbered. In April 1970, I was informed by Joy Manufacturing Company that it was introducing a complete line of quieter compressors, ranging from 175 cfm to 1,200 cfm. The design goal was 85 decibels at 1 meter for a premium of 25 per cent, and 90 decibels at 1 meter for an increase in cost of 10 per cent. Electric air compressors, heretofore kept under wraps by their manufacturers, are now being used for tunnel projects, and for public works sites where militant residents insist on quieter operations. The first electric compressor I experienced was in 1966 in Zurich. Serving a major street renovation project, it was, compared to the monsters on Sixth Avenue, almost ajoy to hear. And no dense diesel fumes on-site.
At that same Lincoln Center demonstration, co-star billing was given to two jackhammers with built-in mufflers, one imported from Holman Bros. and the other discovered in the catalogue of Chicago Pneumatic Tool Co. Both were some hefty 10 decibels less than their noisy unmuffled competitors.
There is nothing impractical about jackhammers with built-in mufflers. The principles governing Holman's design improvement are: 1) the performance of the machine cannot be noticeably reduced, 2) its bulk or weight cannot be increased to the point where it becomes difficult to handle, and 3) the additional cost is to be moderate.
Today other American companies are making quieter jackhammers, and one puts out an accessory muffler that fits around the shaft of any regular jackhammer. Electric hammers are available and eliminate the punch of the pneumatic exhaust. The French are marketing, in the United States, hydraulic paving-breakers with a patented treatment of the internal piston that reduces much of the noise from that source. They combine the breaker with a small silenced compressor as a special package for utility company night work. Hughes Tool Company markets a rotary "cookie cutter" that quietly cuts circular holes in pavement. The primitive mechanical pile driver, with its day-long pounding and pounding, can be silenced by substituting the hydraulic and sonic equipment now on the market.
Of course, silencing is a relative term. For example, what has been accomplished is not to make construction noise a desirable neighbor, but at least to soften some of the naked sounds of construction machinery.
The question always raised is: what noise level? The German Health Ministry realizes existing knowledge does not permit drawing a hard and fast line to divide health-injuring noise from noise that is merely "annoying." Lacking a specific exposure limit (combination of time and noise level), Germany nevertheless seeks to promulgate laws requiring the reduction of intense noise—at its sources. In 1965 the West German government put noise curbs on construction projects.
The operator of construction machinery must see to it that all noises which, according to the latest technical developments, it is possible to avoid or minimize are avoided or minimized, and also see to it that the emanation of unavoidable noises from the construction site be kept to the absolute minimum possible. The operation of a machine that does not comply with these stipulations can be prohibited until the noise is reduced. This is much more effective than a fine.
Switzerland was regulating construction noise before 1965. In 1964, Zurich's noise control office investigated 303 construction sites. Several projects were shut down until the contractors found methods to reduce noise. Austria makes possible an immediate reduction in construction-equipment noise by applying an existing law, the gist of which is that noise made in an "improper" manner is punishable. If noise emanates from a tool that is not technically up to date, it could be interpreted to be an "improperly" made noise. Compressed air equipment lacking muffling would fall into this category.
In America, regulatory agencies, such as the Transit Authority, have the power to curb construction noise without any new legislation. All they have to do is enforce the silencing clause that is standard in many contracts awarded by public agencies. Could any wording be more explicit, or more completely ignored, than the silencing clause in the subway extension contract between the Transit Authority and the contractors? "The contractor must perform all work in such a manner as to create a minimum of noise. He may be required to shield or otherwise cover or insulate his operations so as to restrict the transmission of noise...(he) shall be solely responsible for the performance of the work in a manner which will not create or constitute objectionable noise or other nuisance to the public..."