Introduction
In a school cafeteria operating at full capacity, noise levels quickly reach levels that interfere with students’ concentration and staff working conditions. Large glass surfaces, spacious interiors, and hard floor and wall surfaces amplify reverberation and quickly make the acoustic environment uncomfortable. Beyond comfort, acoustic regulations impose specific requirements on educational institutions. Undertaking soundproofing work without a prior acoustic assessment exposes project owners to misdirected investments and ongoing non-compliance.
Noise in the cafeteria: A health and compliance issue
The cafeteria is one of the most acoustically critical spaces in a school. During mealtimes, the combination of conversations, the clatter of dishes, kitchen equipment, and foot traffic generates a continuous noise level that frequently exceeds 80 dB(A). This level exposes occupants to significant auditory fatigue and impairs communication between students and cafeteria staff.
The consequences go beyond mere discomfort. Prolonged exposure to high noise levels has documented effects on users’ concentration, stress levels, and health. For school cafeteria staff, these conditions amount to occupational noise exposure, which is regulated by the Labor Code. Local governments that own the buildings bear direct responsibility for these operating conditions.
Noise Regulations in Educational Institutions
The decree of April 25, 2003, serves as the reference document forbuilding acoustics in educational institutions. It sets specific requirements for several indicators: reverberation time in classrooms and common areas, airborne sound insulation between rooms, noise levels from technical equipment, and impact noise levels. For cafeterias, the average reverberation time must not exceed 0.8 seconds in the octave frequency bands from 250 Hz to 2,000 Hz.
These requirements apply to new construction and major renovation projects. For older buildings, achieving compliance presents a real challenge, especially since their traditional architectural features—large windows, high ceilings, and hard flooring—are structurally detrimental to controlling reverberation. Demonstrating compliance with the regulation requires field measurements and a validated acoustic simulation, not just a subjective assessment.
Diagnosis and On-Site Measurements: Measure Before Treating
Any acoustic work on a school cafeteria must begin with a structured acoustic assessment. This phase consists of two complementary parts. The first consists of measurements taken when the space is empty: reverberation time by frequency band, residual noise levels from technical equipment, and characterization of the space’s intrinsic acoustic performance. The second component is conducted under real-world conditions during meal service: continuous sound level measurements, identification of dominant sources, and mapping of critical areas.
These acoustic measurements are performed using Class I sound level meters and calibrated reverberation time measurement equipment. They provide an accurate database on the actual acoustic conditions of the space, which is essential for building a reliable digital model and avoiding the main pitfall of this type of project: applying generic solutions—wall panels, sound-absorbing drop ceilings, sound-absorbing furniture—without knowing which frequencies are actually problematic or which surfaces are the primary contributors to the problem.
Acoustic Modeling and Simulation Using CATT Acoustic
Based on on-site measurements, the engineering firm creates a precise volumetric and acoustic model of the dining hall using certified simulation software—CATT Acoustic—designed for spaces with high reverberation. This model incorporates the exact geometry of the space, the existing materials along with their actual absorption coefficients by frequency band, and the furniture as it is actually arranged. No parameters are approximated: the accuracy of the model directly determines the reliability of the simulations.
The model is first calibrated against field measurements to ensure that the simulated results match the measured values. This validation step is essential before any predictive use. Once calibrated, the model can be used to simulate various acoustic treatment schemes—including the type, surface area, and placement of absorptive materials—and to quantify the expected improvements in reverberation time and sound level. This provides the project owner with a performance estimate before any budgetary commitment is made, thereby supporting the investment decision.
The Acoustic Engineering Firm’s Approach
SIM Engineering conducts its projects in school cafeterias according to a three-phase process. The on-site diagnostic phase combines measurements taken under no-load conditions and under actual operating conditions, using certified acoustic measurement equipment. The modeling phase creates a digital twin of the space, calibrated based on the measurements. The simulation phase defines the optimal treatment plan and validates the expected improvements prior to construction, in accordance with the requirements ofthe decree of April 25, 2003.
This step-by-step process ensures that each recommended solution—suspended acoustic panels, sound-absorbing drop ceilings, sidewall treatments, and appropriate furniture—is sized based on the actual data of the space rather than on generic empirical rules. The acoustic report submitted at the conclusion of the study presents the measurement results, the simulation model, a comparison of treatment scenarios, and expected performance. This document serves as the technical basis for discussions with the project manager and justifies the selected options to the local government’s technical departments.
Conclusion
Improving the acoustics of a school cafeteria without a preliminary assessment risks resulting in costly and ineffective renovations. Compliance withthe decree of April 25, 2003, and long-term user comfort are achieved through a rigorous process: on-site measurements, validated modeling, and simulation of acoustic treatments prior to investment. SIM Engineering, an acoustic engineering firm, supports local governments, project managers, and architects on all their school acoustics projects. For any project involving the acoustic retrofit of an educational facility, contact SIM Engineering to obtain a tailored assessment.