<p>The sound field driven by piping systems in enclosures may severely affect living comfort, which is frequently encountered in various engineering applications. Managing this sound field relies heavily on the available prediction tools at hand, e.g., the widely used finite element methods are computationally expensive due to the necessity to discretize entire space, analytical models, based on modal expansion method, may offer substantial advantages in terms of computational cost and efficiency. However, deriving eigenmodes of irregular enclosed spaces may be challenging, which impedes accurate and rapid predictions of the sound field in practical applications. This study presents an analytical framework aimed at rapidly and accurately predicting the interior sound field driven by the piping system vibrations in irregular enclosures. Vibration response of the piping system is obtained using the wave approach, and a line dipole source is idealized as the sound source of the piping system vibration. On the basis of eigenmodes of regular enclosures, the Kirchhoff-Helmholtz integral theorem (modal expansion method for irregular enclosures) is introduced to account for the boundaries of irregular enclosures. This theoretical framework is validated through numerical simulations by finite element method and experiments, demonstrating high accuracy and significant efficiency advantages. The proposed method can be further employed to optimize radiated sound fields by tailoring the impedance of space walls or layout of piping systems. This study provides an efficient tool for predicting radiated sound field in general enclosures driven by vibration of piping systems, paving a new path for indoor acoustical optimization.</p>