This recommended practice is intended to apply to relieving devices and their discharge systems on pressure vessels designed for operating pressures of more than 15 psig. Other considerations@ such as an estimation of the heat input from an exterior fire@ are applicable to all vessels within refineries. Pressure vessels used for transportation of petroleum products@ in bulk or in shipping containers@ are not within the scope of this recommended practice. Inasmuch as pressure-relieving devices only protect a vessel against overpressure and not against a bursting failure when exposed to fire@ means are suggested in this recommended practice both for reducing the pressure to near atmospheric and for restricting the heat input.