The German gas supply system is safe, efficient and eco-friendly. Hence, it has been ranking top for decades by European and international comparison. Thanks to the highly efficient DVGW safety regulations, gas is one of the safest and best-accepted energy carriers.
In terms of safety and environmental protection, Germany ranks top by European and international standards.
Natural gas travels through a widely ramified grid of buried pipelines, invisibly and well protected in the ground, from the source to the domestic service connection. It encounters along its way numerous delivery points and compressor stations as well as underground storage facilities and gas metering and pressure reduction stations, all of which are important components of the natural gas infrastructure. This gas infrastructure, which was built over decades, is crucial for ensuring that one of the most important energy carriers is reliably supplied to Germany as well as to other European countries. In this context, safety always comes first.
The German gas industry provides for the highest possible degree of technical safety, which is rooted mainly in the stringent design, construction and operation regulations defined by the DVGW Set of Rules. Thanks to the high standard that has been attained in the course of the decades, the German gas infrastructure is one of the safest in the world. An international comparison of damage or accident data shows that Germany ranks among the best countries, in spite of her extremely complex and dense pipeline network. If all pipelines were laid end-to-end, they would circle the earth about 13 times.
The protection of humans and of the environment has top priority along the entire gas supply process chain – from design to construction to operation. The holistic safety concept of the DVGW clearly reflects this philosophy, which in addition to the set of strict rules also specifies requirements pertaining to the qualification and certification of products, individuals, service providers and companies.
Diagrams for the illustration of the safety of natural gas
The DVGW Gas Damage and Accident Statistics (website, in German only), which the Association has been keeping since 1981, forms the basis of the DVGW safety concept. All gas grid operators are obliged to report and submit detailed information about all events that involve the inadvertent release of gas. Based on the analysis of the data provided, technologies and procedures are being continuously improved and further training and information measures developed that are incorporated into the DVGW Set of Rules and thus find their way into practice.
The rule-setting process takes into account not only the findings from damage statistics but also, and particularly, scientific research specifically conducted with the intention to advance the technical safety of the gas supply grid. The findings garnered from research projects as well as from other sources such as, for instance, developments in jurisdiction, publications, international sets of rules as well as experiences, are the decisive criteria that form the basis of the DVGW rule-setting process.
Natural gas escaping from a leak is basically harmless as it is lighter than air and liquefies rapidly. A so-called explosive atmosphere will form only if a certain mixing ratio with air (oxygen) is achieved, i.e. when a large amount of natural gas has accumulated inside a closed room or escaped from a pipeline. The critical range is a mixture containing about 4 to 16% of natural gas in the ambient air. In these conditions a small spark will suffice to cause an explosion.
As accidents involving natural gas are almost as rare as death from lightning strike, the Federal Statistical Office of Germany decided some years ago to cease to record them because of their rare occurrence. Since 1981 the DVGW however has been keeping as part of its holistic safety concept its Gas Damage and Accidents Statistics, which cover all events and accidents involving natural gas in Germany. Operators are obliged to collect data on all events involving the inadvertent release of gas and submit them during an annual data collection process. Additionally, all so-called immediately reportable events, i.e. events involving personal injury, deflagration, explosion, conflagration or flying debris, must be immediately reported to the Federal Ministry for Economic Affairs and Energy, the respective regulatory authority, the DVGW Headquarters and the respective regional association of DVGW.
The falling trend in absolute total accident figures, which is currently at a historical record low, impressively demonstrates the high safety level of the German gas supply grid. Since 1981 the number of accidents at pipelines has decreased by 90% despite the fact that the total network length has increased more than twofold over the same period of time. Accidents involving domestic gas installations have also declined continuously: Over the last 15 years only one to two accidents per one million natural gas-heated homes have been recorded annually.
Statistically, accidents or malfunctions involving gas installations occur very rarely. Between 2000 and 2017, 56 per cent of the few accidents and/or immediately reportable events involving personal injury, explosion or conflagration that occurred in conjunction with domestic gas installations were due to flaws caused by customers, attributable, e.g., to intent, imprudence, improper interference or deferred maintenance. The DVGW Set of Rules specifies numerous so-called active and passive measures designed to counteract intentional tampering with gas installations with the intent to kill or commit suicide. These measures include, among others, the installation of special components that impede tampering by automatically interrupting any undesirable release of gas. Passive protective measures have been added, too, e.g. the setting-up of gas installations in rooms not accessible to the general public and the use of safety locks.
The majority of immediately reportable events involving such pipelines are caused by external mechanical interference from machinery used for earthwork in the building industry or by external thermal impacts - frost or heat - as well as by improper working. Damage caused by excavation work provokes the most accidents and affects all pipeline types, e.g. power and water lines as well as telephone cables. The annual damage caused by these accidents amounts to a three-digit million-euro volume. For this reason, DVGW, Deutsche Telekom, VDE (Association for Electrical, Electronic & Information Technologies) and AGFW have jointly founded the BALSibau working group, with the intention being to counteract this wide-spread problem by offering guidance and training courses aimed at reducing and/or avoiding accidents and damage during earthwork and civil engineering activities in the vicinity of pipelines.
As operators of high-pressure long-distance pipelines have to follow especially strict safety procedures, events involving the inadvertent release of gas are relatively rare. Statistical analyses show a marked decline in damage incidence with increasing pipeline diameters. In particular damage by excavation work - the main cause of damage to thinner pipelines – rarely affects high-pressure gas pipelines thanks to their greater wall thicknesses. A great wall thickness also offers a very high degree of corrosion protection, which is increased further by other existent corrosion protection measures.
As a technical-scientific association, the DVGW is responsible for setting the rules that govern the public gas supply grid and, consequently, bears the heavy responsibility for ensuring that it is technically safe. While the state defines the legal framework in the form of laws, acts and ordinances, it however refrains from establishing the details of the safety regulations. Rather, it makes explicit reference to the duty to observe and abide by the DVGW Set of Rules and confines itself to exercising reserved control. This arrangement confers on the DVGW Set of Rules the status of a legal instrument, which on the one hand offers companies and businesses legal certainty, while on the other it supports the state in the form of a technically independent authority.
Grid operators and/or gas supply utilities are obliged to build and operate their plants and systems in such a way as to ensure their technically safe operation. In this context, it is mandatory for them to observe and abide by the DVGW technical rules.
Looking back on more than 150 years of experience, the DVGW in its capacity as an independent body pools the interdisciplinary specialist knowledge of experts from ministries, government agencies, companies and science. Various committees constantly update the technical rules in a transparent process, taking into account the latest findings from the field. This process ensures that the technical rules always reflect the state of the art, guaranteeing the maximum level of safety in the gas supply industry.
This system of technical self-management has proven its worth for many decades. It has helped create an extremely safe and reliable gas infrastructure that is second to none by international standards. From pipeline engineering to plant engineering to domestic engineering - the DVGW Set of Rules covers all aspects of gas supply, and its stringent and comprehensive requirements guarantee the maximum level of safety for humans and the environment alike.
The DVGW Set of Rules, the DVGW certification scheme for individuals, companies and products as well as the relevant in-service training courses endow the gas sector with a package of measures whose consistent application ensures technical safety in Germany.
Impeccable materials and qualified staff are indispensable for ensuring the safety of German gas supply systems. The stringent and comprehensive provisions stipulated by the DVGW have greatly contributed to the fact that German safety standards represent the highest level by international comparison. Only companies and persons that are technically qualified and have passed a mandatory verification procedure are allowed to work on gas pipelines.
Certification on the basis of the DVGW Set of Rules is THE standard for building contractors, manufacturers and gas pipeline workers to prove that they meet all requirements on quality and technical knowledge. For more than 70 years the DVGW has been maintaining a system of testing and certification that is especially tailored to the needs of the gas and water sectors and attaches top priority to neutrality, quality and reliability.
Boasting a share of approximately 48%, natural gas is by far the most popular energy carrier on the heat market, heating almost every other home in Germany. The DVGW Technical Rules on Gas Installations (TRGI) define the safety standards that apply to gas installations in buildings, thus ensuring that natural gas can be safely used at all times. The TRGI form the basis for legally and technically correct work and cover all aspects of domestic gas installation from construction to operation to maintenance. It is, in other words, mandatory reading for installers, utility personnel and grid operators as well as for chimney sweeps, designers and government agencies.
The DVGW’s comprehensive range of further education and training options for the energy and water industry ensures a high standard of education, training and qualification. Every year approximately 30,000 persons from the industry participate in more than 2,400 vocational training seminars. Additional qualifications such as, for instance, gas leak detection specialist training, are indispensable for ensuring the technical safety of the gas infrastructure and form an integral part of the DVGW Set of Rules. This guarantees the exclusive deployment of technically qualified staff, which is not only crucial for maintaining technical safety levels but also provides an efficient preventive measure to avoid damage and accidents.
A range of special training courses is dedicated to preventing damage caused by excavators during civil engineering operations.
Once the construction work is finished, the pipeline network is permanently monitored during operation. All pipeline network operators maintain control centres for round-the-clock pipeline monitoring so that local staff on stand-by duty can be alerted at any time. The DVGW Set of Rules stipulates additional regular inspection and maintenance measures that form an integral part of the safety concept such as, for instance, dedicated helicopters for surveillance by air, highly sensitive detection devices for surveillance on foot or so-called pigs equipped with high-tech sensors that traverse the pipelines. All these measures help to identify and repair even the minutest damage at a very early stage.
Corrosion protection is another crucial element of pipeline safety as it helps forestall damage to the material.
The protective measures provided by the DVGW Set of Rules cover the entire journey of the natural gas from its source to the consumer’s home. It comprises approximately 340 sets of rules that apply to gas and specify detailed provisions for all components of the gas infrastructure, with a special focus on both the approximately 40,000-km-long network of long-distance pipelines that transmit, at high pressure and over long distances, enormous amounts of energy to the supply areas on the one hand, and on the associated gas distribution network with its length of approximately 500,000km on the other.
Observing and abiding by the stringent requirements of the DVGW Set of Rules across the entire process chain, i.e. from design to construction to operation and, finally, maintenance, is mandatory in order to protect humans and the environment against potential hazards and to ensure a maximum level of safety for the gas grid.