Steam boilers and steam pipes under IBR

Steam pipes
IBR steam pipe means any pipe through which steam passes from a boiler to a prime mover or other user or both if pressure at which steam passes through such pipes exceeds 3.5 kg/cm2 above atmospheric pressure or such pipe exceeds 254 mm in internal diameter and includes in either case any connected fitting of a steam pipe.

Steam boiler

Steam boilers under IBR means any closed vessel exceeding 22.75 liters in capacity and which is used expressively for generating steam under pressure and includes any mounting or
other fitting attached to such vessel which is wholly or partly under pressure when the steam is shut off.