# Analysis of the Causes of Excessive Noise and Vibrations of Live Steam Pipelines
## 1 Introduction  
Power plants and heating power stations have a significant influence on the atmospheric air, soil, and water and, in effect, on plants, animals, and people, i.e., on the natural environment. Such influence is exerted by:  
* Products of fuel combustion, i.e., produced as by-products of the power plant fuel cycle. Such products include the following: fumes containing fly ash (dust), sulfur dioxide, nitrogen oxides, carbon monoxide and dioxide, slag from boilers, and waste and wastewater from fuel desulphurization (dustiness also occurs during the transport, storage, and unloading of fuels). * The natural environment is significantly affected by industrial wastewater, which is the by-product of water purification for steam cycles and cooling cycles and is also produced by fuel desulphurization systems, as well as systems for heating water in rivers (lakes) if turbines are cooled by means of an open cooling system. Closed cooling systems--based on ventilators and towers--produce noise [1, 2, 3], which leads to complaints from residents in nearby areas. * Electrical networks, through the impact of electromagnetic fields, also have a detrimental effect on the natural environment. * Noise. * With the progressing knowledge about the influence of sound on human performance, the development of countries, and the awareness of societies, noise pollution has become a regular aspect of environmental planning and protection. With that, requirements for all the industrial installations, especially those erected in past few decades, have put more focus on noise generation. * There are many places in the power-generating units of a power plant that create the following types of noise:
* Noise caused by transformers and engines;* Noise caused by turbines [4];
* Noise caused by the unloading and crushing of coal;
* Noise produced by air and fume extraction fans and compressors;
* Noise caused by steam collectors;
* Noise from other sources. Protection against noise has become a challenge for the entire civilization. Currently, all power plants are required to prepare inventories of noise sources and measure the average sound level. Power plants must also implement a noise reduction program by acquiring low-noise-emission equipment, building anti-noise barriers and noise dampers, and soundproofing the facility [5]. Basic investments aimed at protection against excessive noise emission include noise enclosures and sound insulation for air and fume extraction fans, acoustic protection of boiler outlet pipes, acoustic enclosures for turbine casing, acoustic protection of air fans in ash storage tanks, an anti-noise wall with a sliding door, acoustic enclosures and screens for several pieces of equipment, and others [6; 7]. In power plants, the situation might be even more complicated, as the interaction of the flowing media might excite structural vibrations. It is a challenge of great importance to secure laminar flow both from the point of view of the process as well as complex aeroacoustic phenomena, often leading to resonant amplification and wideband noise emissions. Properly designed geometry of the media guiding structures is of great importance. Additionally, the application of the attenuating materials can be taken under consideration. Recent years have brought great development in sustainable damping/attenuating materials and especially great promise in the application of novel acoustic metamaterials [7]. However, one has to keep in mind that the power plant is a harsh environment with elevated or even extreme temperatures. In one of the coal power plants (Figure 1), it was noticed that one of the live steam pipelines vibrated and generated an excessive level of noise in comparison to the other similar ducts. Additionally, that unusual noise presence was observed shortly after maintenance operations.