Sound insulation of doors - Part 1: Prediction models for structural and leak transmission

Examination of sound insulation of doors presupposes two separate transmission paths to be considered: the structural transmission through the door leaf and the leak transmission through the slits. In this paper, simple prediction models for both transmission paths are presented which are applicable for most types of passage doors. The practicability of the selected models are of great concern to obtain a high degree of utilization in product development. Most doors are designed nowadays as double-panel structures with sound absorbing and fire-resistant materials in the air cavity. Strong interpanel connections are often present at least in the edges of the door. Sharp's double-panel prediction model was found appropriate for modelling both single- and double-panel doors. The slit transmission can be estimated at least by two different theories. The simple model assumes perfect transmission through the apertures. The more profound Gomperts model enables the evaluation of structurally regular slits. The total sound reduction index of doors is predicted from the area-weighted sum of the structural transmission and the slit transmission. Acoustical structure and airtightness of the door shall be developed hand-in-hand to obtain the optimum performance of the door. The prediction models presented in this paper are verified in the second part for 18 steel doors and timber doors [1]. (C) 2000 Academic Press.