Rupture discs and burst discs are designed to open and relieve overpressure, high temperature, or vacuum conditions at a predetermined differential pressure or specific temperature. They may be thermally or mechanically actuated. A rupture disc burst indicator alerts operators that a rupture has occurred. In the biotech, pharmaceutical and food and beverage industries, a sanitary burst indicator meets the requirements for sanitary installation and operation such as clean-in-place, steam-in-place, and FDA-approved gasket materials. Rupture disc accessories include burst checks, burst indicators, clamps and ferrules. A safety buckling rupture disc is designed to actuate without fragmenting. A pressure burst disc bursts when pressure exceeds a stated amount. A burst disc relief valve is primarily used for liquids. Rupture discs and burst discs come in two designs: tension type rupture discs (installed with process pressure against the concave side of the disc) and reverse-acting rupture discs (installed with the process pressure against the convex side of the disc).
Product specifications for rupture discs and burst discs include burst pressure, size, fragmentation on burst, relief valve isolation, non fragmenting design, resistance to fatigue, maximum operating ratio, compatibility with fluids, temperature range, and leak tightness. When selecting rupture discs and burst discs, size is important for safety reasons, particularly the minimum net flow area and the certified flow resistance factor. Rupture discs and burst discs can be sized using one of three methods: the coefficient of discharge method (KD), the resistance to flow method (KR), and the combination capacity method.
Standards that apply to rupture discs and burst discs include the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Section VIII, Division 1, the American Petroleum Institute (API) Recommend Practice 520, and CE Pressure Equipment Directive 97/23/00. An ASME code rupture disc carries the UD code symbol. The International Organization for Standardization (ISO) standards that apply to rupture discs and burst discs include ISO 4126-2 and ISO 6718.