Definition
Burst height is the altitude at which a shell opens, and burst diameter the width of the resulting bouquet; together they define the volume of sky the effect occupies. Both depend first on calibre: as an order of magnitude, a shell climbs roughly as many metres as its calibre has millimetres, that is 75 to 100 m for a 75 mm, 100 to 130 m for a 100 mm, 150 to 200 m for a 150 mm, and more for 200 and 300 mm, with an opening diameter of the same order. Lift charge, mortar length, angle, wind and temperature alter these values. Manufacturer sheets give height, diameter and rise time; these are the figures used to size the site, to stage calibres at different heights and to set the synchronisation.
In practice, for the display company
Height and diameter decide the layering of the show: cakes low, 75 and 100 mm in the middle, 150 mm and above at the top. PyroDesk stores these values on every product sheet, and PyroSimulator sizes each burst from its calibre, star size and duration included, so you can judge on screen whether the sky is full, hollow or saturated.