<b>Relation between Area of Opening and Range of Splash of Testing Fluid during Hydro Testing of Knife Gate Valve</b> Determination of relations between various variables is necessary while designing any experiment. Various methods may be employed depending on the availability of resources at the experimental setup. However, while the experiment is being designed, it is equally important that the same is backed by theoretical formulae. If not derived or proved already, new ones can definitely be derived using first principles. In this study, a relation between the area of opening and range of splash shall be derived. The aim of this relation shall be to get a basic comprehension of the variation in parameters in relation to the range of splash of testing fluid. The concepts of range of splash and area of opening shall be reported at the initial stage. The area of opening shall then be determined using the method of integration considering variables involved in the formulation. On obtaining an expression, a relation between the area of opening and the range of splash shall be derived. Towards the end a conclusion shall be drawn reporting the proportional relations between the variables. Range, area, splash, hydro, testing 1-4 Issue-1 Volume-5 Gourav Vivek Kulkarni