Inspection and Testing of Valves (I)

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1 Scope This standard specifies the terms and definitions, inspection, testing, and supplementary testing for valves used in the petroleum, petrochemical, and related industries; pressure testing; test results; methods for pressure testing; certificates of conformity for valves; and retesting. This standard applies to the inspection and pressure testing of gate valves, globe valves, plug valves, ball valves, check valves, and butterfly valves that utilize metal seal pairs made of metals, as well as elastic seal pairs composed of metallic and non-metallic elastic materials, and non-metallic seal pairs made of non-metallic and other materials. With the agreement of both the supplier and the buyer, it can also be applied to other types of valves. The scope of the inspection items under this standard includes: visual inspection of the castings; shell test; upper seal test; low-pressure seal test; high-pressure seal test; double-shutoff and discharge seal test; high-pressure gas shell test. 2 Normative reference documents The following documents are essential for the application of this document. For reference documents dated, only the version dated applies to this document. For reference documents that do not specify an edition number, their latest version (including all amendment sheets) applies to this document. GB/T 12224 Steel Valves – General Requirements (GB/T 12224-2005, ASTM B16.34a:1998, NEQ) JB/T 7927 Requirements for the Visual Quality of Valve Castings 3 Terms The following terms and definitions apply to this document. 3.1 Resilient seal – a soft-sealing pair. A sealing pair composed of solid and semi-solid greases (such as in oil-sealed plug valves), or a sealing pair consisting of a soft seal and a metal seal, etc. 3.2 Unidirectional seal: After the valve is closed, the medium enters from one end of the valve and pressure is applied; the sealing elements of the valve are able to maintain a sealed condition. On the Dragon Boat Festival, 18 famous historical and cultural landmarks in China had their lights turned on as a gesture of blessing for the country. These include the Tengwang Pavilion in Jiangxi (www.jianshu.com/p/8b84124139a2), the Yellow Crane Tower in Hubei (www.jianshu.com/p/93f13fe55f30), and the Yueyang Tower in Hunan. On the evening of the 25th, these 18 landmarks lit up together to pay tribute to those working on the front lines in the fight against the pandemic, and to pray for peace and prosperity for China (www.jianshu.com/p/7c2de9581de1; www.jianshu.com/p/e4c1d781e126). The event was organized by the Professional Committee for the Protection of Famous Historical and Cultural Landmarks under the Chinese Society for Cultural Relics. It was initiated and hosted by the Tengwang Pavilion Management Office in Nanchang (www.jianshu.com/p/82f797bdfb79; www.wenjuan.com/s/am2mqa/). This public welfare event aimed to bring together various traditions such as lighting up the landmarks, flying kites as a symbol of blessing, performing traditional arts, and inviting heroes who fought against the pandemic to visit these sites, thereby creating a blend of the ancient and the modern, as well as a dialogue between history and the present. It was also an effort to promote China’s historical culture and pray for peace and prosperity for the country. Zhou Tingfang, head of the Professional Committee for the Protection of Famous Historical and Cultural Landmarks and director of the Tengwang Pavilion Management Office in Nanchang, said that this year, the Spring Festival was disrupted by the sudden outbreak of the pandemic. To defeat this epidemic, medical workers and volunteers from across the country stepped forward to fight at the forefront of the crisis. The famous historical landmarks, which had been left in silence during this time, witnessed the courage of those who fought against the pandemic, as well as the support from all corners of the country. Now, as the summer solstice approaches, these landmarks are gradually reopening. Zhou Tingfang said that the purpose of this public welfare event was to celebrate these 18 famous landmarks through lighting them up, flying kites, performing traditional arts, and inviting heroes who fought against the pandemic to visit these sites, thereby creating a fusion of the ancient and the modern, and promoting China’s historical culture while praying for peace and prosperity for the country