Environment and Safety
Impact of the Gas Pipeline on the Environment and Public Health
Most pipelines are buried in ground passing through uninhabited areas. Natural wealth requires protection, and therefore the route avoids protected areas and sensitive locations (for example natural or architectural monuments). The third proposed route was rejected for environmental reasons – it was the only one to pass through a highly protected area. The main goal of both the investor and the designer is to restore the original state of the landscape as early after the pipeline installation as possible.
Generally, it is possible to say that gas pipelines are highly considerate of the environment. They do not pose any threat to landowners and/or to inhabitants living in their vicinity. The placement and technical execution of the gas pipeline satisfies the highest safety standards, provided that the restriction of certain activities in the protective zone with a width of two meters to each side of the pipeline axis is observed. A free strip of land with the same width is maintained in forest sections. Unlike automobile transportation, underground transmission does not pollute the atmosphere. The environmental impact can thus relate only to the period of pipeline construction – excavation, trench establishment, and subsequent pipeline installation, and its backfilling. The entire pipeline is not constructed all at once, the work takes place in a sequence. Therefore, there is no stationary construction site like during the construction of an automotive factory or some other similar facility. Even the number of workers and machines required for individual sections cannot be compared with the construction of large halls. All of the machinery will only stay in the dedicated working zone delimited with poles and on access roads with a width of 36 meters in open terrain and 30 meters in forest areas.
There is no data available about any health problems that would relate to pipelines located in the vicinity of residential buildings. The operation does not produce any noise or dust, and the pipelines do not emit any radiation or waste products into the atmosphere. No waste waters or pollutants are discharged into surface waters. The quality of surface or underground waters or water sources is thus not influenced.
The construction is subject to the permission of the Ministry of Environment of the Czech Republic based on the project’s environmental impact assessment (EIA) pursuant to the provisions of Act No. 100/2001 Coll. The assessment covers all possible impacts of pipeline operation and construction on public health and the environment, as, for example, the impact on animals, plants, ecosystems, soil, water sources, the atmosphere, the climate and landscape, natural resources, tangible property, and cultural monuments.
Safety of High-Pressure Pipelines
In the more than thirty years during which natural gas has been transported from Russia to the Czech Republic, there has not been a single interruption of supply or an accident causing fatalities or major material damage. And, considering the current technology and safety requirements, the probability of an accident involving a pipeline explosion is really very low. The construction of a high-pressure pipeline is subject to rigorous safety standards.
Pipes manufactured from high strength steel are used for pipeline construction. All welds are tested. Each section of the new pipeline route is furthermore subject to a hydrostatic test. Pipes and welds are protected by factory fitted insulation and provided with cathodic protection.
A so-called “stress-test” must be performed before the commissioning. This test is used to verify the tightness of the pipeline and fittings, as well as other equipment, using water pressure.
A supervision and maintenance program is carefully observed for each high-pressure pipeline in operation. The reliability of the operated gas pipelines is assured by periodical internal inspections of all pipelines. These inspections use the method of material loss or internal fault identification using changes in the magnetic field. This measurement is carried out with a special inspection piston – a so-called “pig” moving at the speed of approximately 3 m/s inside the pipeline. The piston is equipped with magnets, magnetic field detectors, and a computer with recording equipment. Critical points within the pipeline can be determined after the evaluation of measured values, and subsequent maintenance work can be scheduled. Pipeline cleaning is carried out annually using a cleaning pig. The cleaning pig is inserted into the pipeline in a system of chambers, and it is subsequently pushed through by the gas pressure under operation. Impurities wiped-off the inner rubber ring surface of the pig are subsequently drained from the terminal chamber into the separator, and into a secured waste tank. This waste is disposed of by a specialized company.