FRALEX-TDP-008: A Tight Bolt Is Not a Tight Joint

A bolted flange joint that has been tightened has shown that tools were used; it has not shown that the joint is tight. This white paper sets out what a bolted joint must demonstrate before it is accepted as assembled: verified components, gasket and lubricant as assumed, a tightening procedure suited to the joint, tools verified, passes and sequence recorded, and a leak test with defined acceptance. It applies the FRALEX Decision Architecture with its three-point Decision Gate, includes an illustrative worked example and decision record, and states when acceptance is not the right answer. It is a decision-support framework, not a tightening procedure or a design specification.