In 2011 the Dutch Ministry of Infrastructure and the Environment (I&M) introduced new legislation for pipelines transporting dangerous substances. This legislation applies to pipelines transporting natural gas and to pipelines transporting oil products and deals amongst other things with the consequences of (new) pipelines on spatial planning. Risk methodologies have been revised in order to reflect new understandings in risk scenarios, failure frequencies and consequences. In the Netherlands operators and responsible authorities are now required to use these methodologies in risk calculations.
A risk methodology for pipelines transporting chemicals (substances other than natural gas or oil products) has currently been developed. These pipelines have a total length of about 3,000 kilometer and 18 different chemicals such as ethylene, hydrogen, chlorine and carbon dioxide are involved. This paper describes the risk methodology for underground pipelines transporting chemicals, including modeling aspects and failure frequencies. The application of measures to reduce the risk and some case analysis results are presented as well.