IS 4991 : Part 1 : 2024 Criteria for Blast Resistant Design of Structures - Part 1 Above-ground Explosions

1 SCOPE

1.1 This standard (Part 1) prescribes the minimumcriteria for analysis and design of new structures for blast effects of above-ground explosions of high-explosives under three different detonation scenarios: surface burst, free-air burst, and air burst. The primary objective of this standard is to minimize human casualties and safeguard assets due to above ground explosions. The performance expectation of a structure designed as per the provisions of this standard would depend on the type of protection category selected for that structure and the blast loading determined through threat assessment.

1.2 This standard shall be used in conjunction withother applicable standards for analysis and design of structures. This standard does not supersede or replace other design standards. This standard shall be applicable if design against malevolent or accidental blast loading is determined to be a credible threat to a structure.

1.3 The owner of a structure is the competentauthority who can determine the necessity of blast-resistant design. In the scenario of accidental and malevolent blast event which may pose public health and safety issue, competent authorities other than the owner of building that govern or regulate the construction, operation, and maintenance of the structural facility, can specify the requirement of blast-resistant design.

1.4 The provisions of this standard do not addressthe following:

a) Estimation of structural loads due tonuclear detonations, pressure vesselexplosions, dust, and vapour cloudexplosions;

b) Effects of cased explosives and shapedcharges;

c) Threats emanating from fragmentation,induced fire or thermal effects, biologicalor chemical radiations, electromagneticpulse (EMP) and deflagration events; and

d) Detonations in contact with structuralelements.