The purpose of this study is that there are two methods for designing firefighting piping: the hydraulic calculation method and the conventional piping method. In the field, the conventional piping method according to the ‘Fire Safety Performance Standards for Sprinkler Equipment’ [Appendix 1] is preferred. There is no mention of the basis and physical meaning of the number of heads for each water supply pipe diameter in the conventional piping method, and the types of pipes that can be used have also increased. Since there was no confirmation as to whether it was appropriate to calculate the number of heads according to [Appendix 1] for each type of pipe, an attempt was made to establish a basis through comparison of regulations in each country and hydrodynamic calculations.
 The research method was to confirm the basis of the ‘Fire Safety Performance Standards for Sprinkler Equipment’ [Appendix 1] through analysis of relevant standards in the US, UK, and Korea. Based on the flow rate in the pipe, the mass flow rate-based head and the number of pipe heads were calculated and compared. As for the type of pipe, KS D 3507, which is the most commonly used, was used as a standard, and KS D 5301 and 3595 pipes were compared to determine whether the number of heads was appropriate. In addition, in order to check the limits of branch piping based on the flow speed limit of branch piping (6 ㎧) and the flow speed limit of other piping (10 ㎧), 25A (25 Su), 32A (30 Su), 40A (40 Su), we checked for changes by increasing the number of branch pipes to 50A (50 Su).
 Through this study, it was confirmed that the basis for the method for calculating water supply pipe diameter by number of sprinkler heads is in NFPA 13. Based on the pipe flow rate, the number of heads was calculated by comparing the head number based on mass flow rate for the head and pipe. Using KS D 3507 as the calculation standard in [Appendix 1], it was confirmed that KS D 5301 and 3595 pipes can be sufficiently used as a result of comparative comparison considering the degree of irradiation. In addition, as a result of increasing the number of branch pipes, it was determined that it was appropriate to use branch pipes up to 40A, and it was confirmed that there was no change as the number of branch pipes increased.
 Through comparison of the standards and the number of heads based on mass flow rate, the basis of ‘Fire Safety Performance Standards for Sprinkler Equipment’ [Appendix 1] was confirmed, and it was confirmed that all KS D 3507, 5301, and 3595 are applicable. In the case of KS D 3595, there are 60 Su and 75 Su as names corresponding to 65A, so it was judged that flexibility in design could be achieved.