A common question I\u00a0get is whether or not flanged and bonneted valves need to be torqued when they are installed. Unfortunately, many of these questions are due to OSHA citations \u2013 Ideally you want to answer this question BEFORE the OSHA inspection.<\/p>\n
The short answer is: Yes<\/strong>, you need to torque valves and bonnets to the manufacturer\u2019s recommendations when you install them.<\/p>\n \u00a0The long answer begins with a little history\u2026<\/p>\n The 2005 version of IIAR-3 (Valves) section 5.8, states: \u201cThe applicable tightening torque values for the valve bonnet, flanges and other pressure-containing attachments to the valve shall be specified by the manufacturer and made available on request.\u201d<\/p>\n Valve manufacturers went ahead and complied with this and every major valve manufacturer that we\u2019re aware of published torque recommendations. The IIAR revised their wording in 2012 to \u201cThe applicable assembly and installation procedures for the valve bonnet, flanges and other pressure-containing attachments to the valve shall be specified by the manufacturer and made available on request.\u201d However, the valve manufacturers had ALREADY posted the torque recommendations.<\/p>\n For one example, R\/S Parker, see page 216-218 of the link below:<\/p>\n R\/S Parker Valve Catalog<\/a><\/p>\n That link would be the \u201capplicable assembly and installation procedures,” right? Even the current version of IIAR-2 states that: \u201c10.5.1 Valves (or flange sets) with specialized tightening requirements shall be installed according to manufacturer\u2019s instructions.\u201d<\/p>\n PSM also requires us to adhere to manufacturer\u2019s instructions:<\/p>\n 1910.119(j)(6)(ii) \u200b \u200bAppropriate checks and inspections shall be performed to assure that equipment is installed properly and consistent with design specifications and the manufacturer’s instructions.<\/p>\n<\/blockquote>\n In my\u00a0opinion, and based on citation history, the belief that valve torque is NOT required is unsupportable. If the valve manufacturers removed all their torque requirements from published documents, then it\u2019s possible the issue could be avoided. But honestly, that\u2019s exactly what they are trying to do \u2013 Avoid the conversation. It\u2019s really infuriating that the same people that wouldn\u2019t think of installing a new head on their hot-rod without a torque wrench are the people that usually give you the most grief about valve torque.<\/p>\n The real question is: Is the flange or bonnet torque important? The answer to that is undeniably: Yes<\/strong>.<\/p>\n Over-torqueing pinches gaskets making leaks more likely and extreme over-torqueing on bonnets can warp them to the degree that it impairs the function of the valve or regulator.<\/p>\n We should torque the flanged valves and bonnets to manufacturer\u2019s specification not because PSM tells us to, or because the IIAR tells us to, or even because the manufacturer tells us to. We should the flanged valves and bonnets to manufacturer\u2019s specification because it is the right<\/strong> thing to do.<\/p>\n p.s. Previous discussion and citation at this link:\u00a0https:\/\/taocompliance.com\/\/?p=380<\/a><\/p>\n p.p.s.\u00a0You can\u2019t torque old bolts reliably. Once you\u2019ve torqued the bolt, you don\u2019t go back and torque it again since the act of tightening a bolt actually stretches it minutely. Lubrication on bolts drastically changes the actual bolt tension for a given torque \u2013 you shouldn\u2019t lubricate bolts that you are going to torque unless the torque specification specifically tells you to. Unless stated otherwise, torque specifications are assumed to be dry, clean and new threads.<\/p>\n \n","protected":false},"excerpt":{"rendered":" A common question I\u00a0get is whether or not flanged and bonneted valves need to be torqued when they are installed. Unfortunately, many of these questions are due to OSHA citations \u2013 Ideally you want to answer this question BEFORE the … Continue reading \n