An explosive is a mixture of compounds which, when initiated by heat, impact, friction, or shock, undergoes a rapid decomposition in the form of heat and gas where tremendous amounts of energy is released. Full or partial collapse of buildings, minor and major cracks are the most perceptible type of failure that may result from a blast load. The level of damage produced in a structure depends on charge weight, distance of building from point of explosion . This work deals with study of nature of blast loading and its effects on regular and irregular multi-storey building with and without shear wall opening.