Once the harmful effects caused by noise emissions was understood, OEM vehicle and engine manufacturers also considered this issue throughout the entire development of their products. In this context, mufflers are a standard part for an exhaust system. Of course, regulations exist to make sure this equipment is in accordance with reasonable emission levels. In Europe, for example, noise emissions from motor vehicles are covered by two directives introducing sound level limits. The construction equipment sector is based in the EEC conformity assessment procedure framework directive, which has led to the adoption of seven daughter directives on particular types of construction equipment.
Directive 70/157/EEC introduces limits on the sound levels of noise for road vehicle and gives requirements for measuring sound levels, exhaust systems and silencers. Several amendments, like the Directive 96/20/EC, have reduced these permissible sound levels. Limit values range from 74 dB to 80 dB.
For construction plants, permissible sound levels are outlined within the framework of directive 84/532/EEC, in seven separate directives, each of them concerning particular pieces of equipment (Compressors, Tower Cranes, Welding Generators, Power Generators, Concrete breakers, Lawnmowers and Hydraulic Excavators). These requirements are in an effort to overcome other variables such as the working conditions these machines are found.
In the US, it is no different. SEC. 36.409 says that "Except for emergency work, it shall be unlawful for any person to operate construction equipment or cause construction equipment to be operated, that exceeds an average sound level of 75 decibels for an eight-hour period, between 7 a.m. and 7 p.m., when measured at the boundary line of the property where the noise source is located or on any occupied property where the noise is being received".
For retrofit purposes, our DPF systems
replace the muffler. If additional reductions are necessary, an additional muffler can be installed at the exhaust outlet module.