DIN EN ISO 21809-5:2019
石油和天然气工业 用于管道运输系统的埋地或水下管道的外部涂层 第5部分:外部混凝土涂层(ISO 21809-5:2017)
Petroleum and natural gas industries - External coatings for buried or submerged pipelines used in pipeline transportation systems - Part 5: External concrete coatings (ISO 21809-5:2017)