c) For standard air pipes of 760 mm height closed by heads of not more than the tabulated projected area, pipe thickness and bracket heights are specified in Tab 27. Where brackets are required, three or more radial brackets are to be fitted. Brackets are to be of gross thickness 8 mm or more, of minimum length 100 mm, and height according to Tab 28 but need not extend over the joint flange for the head. Bracket toes at the deck are to be suitably supported.