Reviewers Omoniyi Ogheneruemu Olagunju and Mishael Emmanuel Bulus used a PRISMA-informed narrative literature approach rather than a systematic or scoping review. Searches conducted between June and July 2026 covered Google Scholar, Scopus and ScienceDirect, supplemented by manual inspection of five journals, citation tracking and eligibility screening for Nigerian public buildings, acoustic design and accessible full texts. The databases initially returned 204 records, but date restrictions, relevance screening and full-text assessment reduced the final corpus to 13 peer-reviewed journal articles or conference papers.

Because the search was not exhaustive, no formal critical appraisal was undertaken and biomedical databases such as PubMed were excluded, the authors describe their framework as an interpretive mapping of the literature rather than a complete assessment of Nigerian acoustic practice. Building geometry and spatial volume were recurring factors in the reviewed studies. Large rooms, high ceilings, domes, vaults and atriums can produce long reverberation times and uneven sound distribution, while room shape can affect the clarity of speech.

Reverberation time, or RT60, is the time required for sound to decay by 60 decibels after its source stops. The review cites target ranges of 0.5–0.7 seconds at 500–1,000 hertz for lecture halls and 1.8–2.1 seconds for concert and music halls, illustrating why a single acoustic target cannot suit every function. Geometry must therefore be considered when planning spaces intended for lectures, sermons, music or conversations, rather than leaving acoustics to be addressed solely with amplified sound after construction.

Surface finishes were another major determinant. Hard ceilings, walls, floors, glazing and plastic seating reflect sound, whereas rugs, carpets, upholstered furniture and absorptive ceiling treatments can reduce reflected energy. Ceilings were identified as a dominant surface in many of the included studies, and recommendations favoured selecting absorption according to the function of each room instead of applying a generic list of products.

In a simulated worship space, suspended ceiling baffles, wall panels and a six-zone delayed loudspeaker array were associated with an RT60 reduction from 3.2 to 1.6 seconds and an increase in the Speech Transmission Index, or STI, from 0.48 to 0.72. These were modelled results from one reviewed study and do not establish that the same package will perform identically in other buildings. Intended activity also shaped acoustic requirements.

University lecture rooms, multi-purpose halls and convention centres may accommodate speech, lectures, exhibitions, performances and social events, requiring a balance between absorption and diffusion. Worship spaces face the related challenge of supporting intelligible sermons while retaining reverberant character for music. Libraries and clinical environments instead emphasize speech privacy and low background noise.

STI, measured on a scale from zero for unintelligible speech to one for perfectly clear speech, is a composite measure incorporating signal-to-noise and reverberation effects; the review notes cited guidance that educational spaces should achieve an STI of at least 0.60. Sound-pressure level and its A-weighted time average, LAeq, describe acoustic energy over an interval, while signal-to-noise ratio compares a desired sound with unwanted background noise. Each metric must be matched to the relevant building function.

Site context and external sources also appeared repeatedly in the evidence. One included hospital study reported average levels of 52–60 decibels across several facilities, which the review compares with cited World Health Organization recommendations of 30 dB LAeq in ward rooms and 35 dB LAeq in treatment and observation rooms. Traffic, generators, steel doors and glass windows were identified among sources of intrusion, and users reported annoyance, exhaustion, distraction, headaches, stress and impaired communication.

These observations support including traffic, mechanical equipment and noisy circulation areas in site selection and interior zoning for hospitals, libraries and other sensitive facilities. They do not establish how external and internal noise sources compare in every building, nor does the review test whether a particular interior treatment is sufficient in a given site. The authors organize transferable measures into six themes.

Architectural strategies include acoustic planning during site selection, orientation, geometry and zoning, rather than adding devices late in construction. Material strategies involve absorptive surfaces, upholstery and potentially bio-based treatments; environmental strategies use appropriately located vegetation as an external noise buffer; and technical strategies combine room design with zoned loudspeakers, digital signal processors, suitable microphones and post-installation tuning. The review treats a strategy as broadly applicable when it addresses an acoustic function relevant to multiple typologies, is not dependent on one geometry, fits Nigerian tropical conditions and uses materials or techniques accessible within Nigeria.

Those qualifications matter because durability, maintenance and lifecycle evidence remain limited. Imported rock wool, acoustic panels and micro-perforated absorbers may add cost, while professional audio equipment requires capital, commissioning expertise, spare-parts logistics and tuning capacity. Vegetative buffers depend on land availability, species selection and upkeep, and their performance in Nigerian conditions requires documentation.

Bio-based materials are described as potentially lower-impact alternatives, but the studies did not systematically compare embodied energy, greenhouse-gas emissions, transport, durability, service life or disposal. Affordability, local availability and environmental performance are therefore related priorities, but they are distinct and should not be treated as interchangeable evidence of sustainability. The distribution of evidence is uneven.

Religious buildings were the most frequently studied typology, followed by educational and performance or arts buildings, while healthcare and commercial buildings received partial coverage. No eligible study represented industrial, transport, civil or judicial, hospitality or recreational facilities, and libraries were absent despite their need to support quiet study alongside collaborative activity. The authors describe these categories as having “no evidence identified in the present search,” rather than as proof that no research or regulation exists.

They also did not systematically audit Nigerian regulatory instruments, so the absence of a national acoustic code from the included studies is not independent confirmation that no relevant provisions exist anywhere in the country. The resulting framework points to integrated acoustic planning supported by empirical verification, context-specific standards, professional training and routine occupant feedback. Designers would begin with the acoustic functions required by the building, then coordinate geometry, orientation, zoning, finishes, technical systems and operating practices around those requirements.

Passive measures using locally available materials may offer accessible options, but their environmental case requires lifecycle analysis and verification of moisture, durability and fire performance. The review does not test a complete strategy in a new building, and it cannot establish a causal pathway from any single intervention to better public-space outcomes. Its contribution is instead a structured map of the Nigerian evidence: the available measures are more varied than a single typology-specific solution, while the research needed to establish durable standards, compare local materials and cover neglected building types remains incomplete.

Subject of Research: Narrative review of acoustic design determinants, strategies and research gaps in Nigerian public buildings

Article Title: Beyond a single typology: applicable acoustic design in Nigerian public buildings

Article References: Olagunju, O. O., & Bulus, M. E. (2026). Beyond a single typology: applicable acoustic design in Nigerian public buildings. Frontiers in Built Environment, 12, 1951241. https://doi.org/10.3389/fbuil.2026.1951241

Image Credits: AI Generated

DOI: 10.3389/fbuil.2026.1951241

Keywords: building acoustics, Nigeria, public buildings, acoustic comfort, speech intelligibility, reverberation control, noise control, acoustic planning, sustainable materials, narrative review, Beyond, single