1 Modeling Noise Levels in USM Penang Campus Hang See Pheng, Teh Su Yean, Koh Hock Lye, Ahmad Izani Md. Ismail and Suraiya Kassim School of Mathematical Sciences Universiti Sains Malaysia 11800 Penang, Malaysia. E-mail: hlkoh@cs.usm.my Abstract. Several research projects have been initiated by the Healthy Campus Concept to promote a healthy environment in USM campus conducive to learning and creativity. Staffs working in the New Science Complex NSC have experienced some noise annoyance due to sound emanating from air-condition exhausts. The air conditioning system is located at about 3.5 meter above ground level, within the compound of NSC. A concern was raised as to whether the noise level produced by the air conditioning system would pose hazards to the staffs and students who work in the NSC for long duration. A research was thus initiated to monitor and model noise level in the vicinity of the sound sources and to propose mitigation measure if deemed necessary. An in-house noise simulation model NOISEPAC was developed for this purpose. This paper will present a synthesis of the sound monitoring to identify locations of high noise levels and discuss noise simulation results performed by NOISEPAC. Key words: NoisePac simulation, sound insulation barrier, healthy campus. 1. Introduction The New Science Complex (NSC) in USM Penang campus was completed in the year 2001 to accommodate staffs and students of the School of Computer Sciences and the School of Mathematical Sciences. An air conditioning system known as the “Air Cooled Rotary Screw Flooded Chillers” was installed to provide comfortable environment to the staffs and students in the 7-storey building. As the air conditioning system is located in the middle of the NSC building compound, the noise emitted by the system may interrupt the learning process in the classroom and may hinder communication in the meeting rooms and offices. Several sources in the air conditioning system that are most likely to generate noise are identified. They include the twin compressors, air cooled chillers and condenser fans. Under the Healthy Campus Program, which strives for a better campus environment, a research project was conducted to assess the noise level emitted by the air conditioning systems. For this purpose, an in-house noise simulation model NOISEPAC is used to simulate the sound pressure level for outdoor and indoor areas of the building NSC. MATLAB is used to generate noise contours to provide a visual image of the sound field over the study area. For the purpose of validating the simulated results from NOISEPAC, the sound pressure level in the surrounding areas of the air conditioning systems was measured by using