the sectional headers being in vertical or substantially-vertical arrangement

Full Title

Water-tube boilers of horizontally-inclined type, i.e. the water-tube sets being inclined slightly with respect to the horizontal plane > built-up from water-tube sets in abutting connection with two sectional headers each for every set, i.e. with headers in a number of sections across the width or height of the boiler > the sectional headers being in vertical or substantially-vertical arrangement