{"id":303,"date":"2019-04-01T04:30:46","date_gmt":"2019-04-01T02:30:46","guid":{"rendered":"https:\/\/www.as-schneider.blog\/?p=303"},"modified":"2020-10-06T11:38:17","modified_gmt":"2020-10-06T09:38:17","slug":"dvt-tat-design-verification-test","status":"publish","type":"post","link":"https:\/\/as-schneider.blog\/2019\/04\/01\/dvt-tat-design-verification-test\/","title":{"rendered":"Challenge of Design Verification Test (DVT\/TAT)"},"content":{"rendered":"\t\t
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Challenge of Design Verification Test (DVT\/TAT)<\/h1>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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In my professional career I have found that in practice there is often misinterpretation in understanding Design Verification\u00a0Test (DVT). DVT is formerly known as TAT (Type Acceptance Test) \u2013 a Shell Specification (MESC SPE 77\/300A).\u00a0<\/strong><\/p>

In the industry, there are many different manufacturers offering valves meeting Shell requirements. Users should also find out if these valves also meet the full Shell MESC SPE 77\/300A Specification. This misinterpretation made me write this post.<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t

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Understanding Shell\u2019s DVT\/TAT (MESC SPE 77\/300A)<\/h2>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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The new term DVT is rarely used in practice. People still use the previous term TAT. That`s why I use in my post both terms.<\/p>

When speaking about testing we also have to differentiate between that two terms:<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t

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1. Factory Acceptance Test (FAT)\n<\/h4>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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The\u00a0 Factory Acceptance Test (FAT) assesses equipment during and after assembly. It confirms that the manufacturers have indeed built it. The FAT also ensures that users are operating it according to design specifications. Manufacturers conduct FATs to check non-conformities and inconsistencies, and to develop a procedure for managing these.<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t

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2. Design Verification Test (DVT\/TAT)<\/h4>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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DVT\/TAT is a term used in Shell specifications, but it also appears in other standards besides Shell.<\/p>

Performing a DVT\/TAT test on a product already needs to be considered in design stage during developing the prototype.<\/p>

The goal of a Design Verification Test is to ensure that a product meets all its design specifications. The DVT\/TAT proves also if the valve design meets specific users` requirements or specifications.\u00a0 For example the Original Equipment Manufacturer (OEM) specifies a P\/T rating. The DVT\/TAT procedure proves or disproves this rating by performing a series of clearly defined mechanical and thermal cycles over the full range of the test valve temperature rating.<\/p>

DVT\/TAT increases customers\u2019 trust in the reliability of a product. It is also useful for finding problems early. DVT\/TAT reduces the likelihood of having to do an expensive fix later on, too.<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t

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General features of a DVT\/TAT test<\/h3>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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In the petrochemical industry, DVT\/TAT involves the testing of valves. Engineers test these valves to their design limits on pressure and temperature (ambient temperature, elevated and minimum temperature). The procedure includes both:\u00a0 Several seat tests with use of nitrogen as well as body tests (static and dynamic) with use of helium to ensure tightness acc. Fugitive Emission Testing.<\/p>

Engineers perform as many as about 200 mechanical cycles including opening and closing torques. The specification bases the acceptance criteria for required seat tests on ISO 5208 and values for shell\/ body tests on ISO 15848 (FE).<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t

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DVT\/TAT is part of a total valve qualification program:\n<\/h4>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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