Calculating Boiler Wall Thickness per ASME Section VIII

In one of the projects I was asked to determine is existing but old boiler is fit for health. Two standards were used to determine this

1. ARAMCO SA 516-70
2. ASME Section VIII, Division 1

Mathematical functions were developed & each minute variable (e.g static heads while boiler is flooded) was taken into account to ensure asset is safe to be used fuurther