Disc selection depends from exercise conditions of the equipment to be protected:
Conventional discs have a flat or concave surface exposed to the pressure. Bursting happens when the pressure (or depression) overcomes the mechanical resistance of the material, after having gradually increased the camber of the disc.
Reverse acting discs have a convex surface exposed to the pressure. The shape of the disc does not change until the pressure reaches the bursting point.
Graphite discs are recommended at low exercise pressure in contact with aggressive fluids. They are normally used at low and medium pressure.
