The Huge Sloped and welded equipments case

Take care if big equipments shall be installed with slope and also shall be welded together in site (as Sulphur reactor with Waste heat boiler).
For instance, large diameters as nine feet, with a slope of one degree create a top projection in the highest equipment (and also a bottom projection in the lowest equipment) of almost one inch. If by mistake the highest equipment will be early installed, erection contractor will found an overlapping of almost two inch (usually they will claim by a foundation mistake)