在异常操作条件下，立式固定顶储罐可能会经历蒸汽压力的快速增加，这会压倒通风装置，并导致储罐故障。EEMUA 180为此类储罐的设计人员和用户提供了指导，指导他们在设计、操作和维护过程中可以采取的实际步骤，以使屋顶到外壳的接头比外壳到底部的接头更容易发生故障，从而确保储罐内容物的保留。这种相对薄弱的屋顶至外壳接缝被称为“脆弱屋顶接缝”。还提供了关于如何确定1985年之前建造的储罐的实际脆弱性的指南（脆弱性成为设计要求的日期）。

Under abnormal operating conditions, vertical fixed roof storage tanks may experience rapid increases in vapour pressure which overwhelm venting devices and lead to tank failure. EEMUA 180 gives guidance to designers and users of such tanks on the practical steps that can be taken in design, operation and maintenance to predispose the roof-to-shell joint to fail in preference to the shell-to-bottom joint, thereby ensuring retention of the tank's contents. Such relatively weak roof-to-shell joints are known as 'frangible roof joints'. Guidance is also provided on how to determine the actual frangibility of tanks built before 1985 (the date where frangibility became known as a design requirement).