Audibility of emergency broadcasting sound in a mechanical room in an office building

2021 ◽  
Vol 263 (3) ◽  
pp. 3811-3816
Author(s):  
Jeongho Jeong
Keyword(s):  
Emergency Operation ◽  
Sound Level ◽  
Acoustic Properties ◽  
Office Building ◽  
Fire Alarm ◽  
Transmission Index ◽  
Broadcasting System ◽  
Disaster Situation ◽  
Alarm Sound ◽  
Clear Presentation

Fire alarm and emergency broadcasting sound are important in fire and disaster situations. For the clear presentation of the fire alarm and emergency broadcasting sound to occupants of buildings, some guidelines and requirements were established. In NFPA 72 and BS standard, a specific alarm sound level for alarm sound of residential facilities was proposed and Speech Transmission Index(STI) was regulated for the emergency broadcasting system. In the fire and disaster situation, one of the important facility is a mechanical and electrical system to maintain water and electricity supply. To maintain this function in the buildings, clear presentation of emergency broadcasting sound to the workers in the mechanical and electrical room is crucial for the emergency operation of the system. In this study, the noise level in the mechanical rooms and electricity facilities of more than 40 years old office building were measured. Also, audibility and room acoustic properties such as reverberation time and STIwas simulated using Odeon 12. In order to deliver emergency broadcasting sound more clearly, sound absorption material and a soundproof chamber for noisy devices are needed. Also, the emergency broadcasting system in noisy facilities should be improved to produce the broadcasting sound louder and clearer.

scholarly journals An Experimental Study of Acoustic Comfort in Open Space Banks Based on Speech Intelligibility and Noise Annoyance Measures

2017 ◽  
Vol 42 (2) ◽  
pp. 333-345 ◽  
Author(s):  
Rostam Golmohammadi ◽  
Mohsen Aliabadi ◽  
Trifah Nezami
Keyword(s):  
Background Noise ◽  
Speech Intelligibility ◽  
Open Space ◽  
Irrelevant Speech ◽  
Acoustic Properties ◽  
Noise Levels ◽  
Noise Annoyance ◽  
Transmission Index ◽  
Acoustic Comfort ◽  
Bank Employees

Abstract Tasks requiring intensive concentration are more vulnerable to noise than routine tasks. Due to the high mental workload of bank employees, this study aimed to evaluate acoustic comfort in open-space banks based on speech intelligibility and noise annoyance metrics. Acoustic metrics including preferred noise criterion (PNC), speech transmission index (STI), and signal to noise ratio (SNR) were measured in seventeen banks (located in Hamadan, a western province of Iran). For subjective noise annoyance assessments, 100-point noise annoyance scales were completed by bank employees during activities. Based on STI (0.56±0.09) and SNR (20.5±8.2 dB) values, it was found that speech intelligibilities in the workstations of banks were higher than the satisfactory level. However, PNC values in bank spaces were 48.2±5.5 dB, which is higher than the recommended limit value for public spaces. In this regard, 95% of the employees are annoyed by background noise levels. The results show irrelevant speech is the main source of subjective noise annoyance among employees. Loss of concentration is the main consequence of background noise levels for employees. The results confirmed that acoustic properties of bank spaces provide enough speech intelligibility, while staff’s noise annoyance is not acceptable. It can be concluded that due to proximity of workstations in open-space banks, access to very short distraction distance is necessary. Therefore, increasing speech privacy can be prioritised to speech intelligibility. It is recommended that current desk screens are redesigned in order to reduce irrelevant speech between nearby workstations. Staff’s training about acoustic comfort can also manage irrelevant speech characteristics during work time.

scholarly journals Acoustical Design and Noise Control in Metro Stations: Case Studies of the Ankara Metro System

2007 ◽  
Vol 14 (3) ◽  
pp. 203-221 ◽  
Author(s):  
Zühre Sü ◽  
Mehmet Çalışkan
Keyword(s):  
Computer Simulation ◽  
Nonwoven Material ◽  
Sound Level ◽  
Reverberation Time ◽  
Acoustical Parameters ◽  
Transmission Index ◽  
Speech Transmission ◽  
Absorbing Materials ◽  
Practical Design ◽  
Metro System

The aim of this research is to demonstrate the importance of initial strategies in acoustical design of underground metro stations. The paper searches for practical design solutions by evaluating different materials for providing optimum acoustical conditions in such spaces. Acoustical designs of three metro stations on a new expansion line in Ankara including Sogutozu, Bilkent and ODTU metro stations are presented through computer simulation. Predictions of room acoustical parameters are presented for both platform and ticket office floors in terms of parameters like reverberation time (RT), speech transmission index (STI) and A-weighted sound level (SPL) distribution within spaces. Simulated reverberation times are evaluated in view of legislative requirements. The study confirms the importance of using sound absorbing materials on the ceiling and sidewalls together. The nonwoven material, used behind perforated metal suspended ceilings, has proved effective in reverberation control.

scholarly journals A Study on Awareness Rate of the Fire Alarm Sound in the Factory

2013 ◽  
Vol 13 (2) ◽  
pp. 163-173
Author(s):  
Young-Sam Lee ◽  
Dong-Ho Rie
Keyword(s):  
Fire Alarm ◽  
Alarm Sound

Acoustics of Classrooms in Primary Schools - Results of the Reverberation Time and the Speech Transmission Index Assessments in Selected Buildings

2011 ◽  
Vol 36 (4) ◽  
pp. 777-793 ◽  
Author(s):  
Witold Mikulski ◽  
Jan Radosz
Keyword(s):  
Correlation Analysis ◽  
Primary Schools ◽  
Building Construction ◽  
Acoustic Properties ◽  
School Building ◽  
Reverberation Time ◽  
Frequency Range ◽  
Transmission Index ◽  
Speech Transmission ◽  
Precise Assessment

Abstract The article presents results of our own research regarding acoustic properties of 110 classrooms in five typical primary schools in Warsaw. The target of the research was to assess the classrooms using established criteria. These criteria include the reverberation time and the speech transmission index. The research has shown a large diversity of acoustic properties of classrooms within each of the schools and between the schools, resulting from the classroom equipment and the school building construction. In addition, the assessment has indicated that classrooms in schools researched do not meet the established acoustic criteria (reverberation time and speech transmission index). Because the classroom equipment is different for younger forms (integrated teaching) and for older forms (subject teaching), the results have been analyzed separately for rooms for younger forms (0-III) and for rooms for older forms (IV-VI). Synthetic results prove the advisability of such division. Correlation analysis has been conducted for the speech transmission index STI and reverberation time Tmf, as well as for the speech transmission index STI and the suggested reverberation time Twf defined in a similar manner as Tmf, but in a wider frequency range. The correlation between the speech transmission index STI and Twf is higher than that between the STI index and Tmf. The reverberation time Twf can therefore be used for a more precise assessment of acoustic properties of interiors with regard to verbal communication than Tmf. In addition, the paper presents estimated analysis results of the influence of selected classroom equipment (carpets) on its acoustic properties.

Evaluation of A “Direct-Comparison” Approach to Automatic Switching In Omnidirectional/Directional Hearing Aids

2008 ◽  
Vol 19 (09) ◽  
pp. 708-720 ◽  
Author(s):  
Van Summers ◽  
Ken W. Grant ◽  
Brian E. Walden ◽  
Mary T. Cord ◽  
Rauna K. Surr ◽  
...  
Keyword(s):  
Hearing Aids ◽  
Predictive Accuracy ◽  
Mode Selection ◽  
Sound Level ◽  
User Preferences ◽  
Acoustic Properties ◽  
Directional Hearing ◽  
Comparison Approach ◽  
Listening Environments ◽  
Automatic Switching

Background: Hearing aids today often provide both directional (DIR) and omnidirectional (OMNI) processing options with the currently active mode selected automatically by the device. The most common approach to automatic switching involves “acoustic scene analysis” where estimates of various acoustic properties of the listening environment (e.g., signal-to-noise ratio [SNR], overall sound level) are used as a basis for switching decisions. Purpose: The current study was carried out to evaluate an alternative, “direct-comparison” approach to automatic switching that does not involve assumptions about how the listening environment may relate to microphone preferences. Predictions of microphone preference were based on whether DIR- or OMNI-processing of a given listening environment produced a closer match to a reference template representing the spectral and temporal modulations present in clean speech. Research Design: A descriptive and correlational study. Predictions of OMNI/DIR preferences were determined based on degree of similarity between spectral and temporal modulations contained in a reference, clean-speech template, and in OMNI- and DIR-processed recordings of various listening environments. These predictions were compared with actual preference judgments (both real-world judgments and laboratory responses to the recordings). Data Collection And Analysis: Predictions of microphone preference were based on whether DIR- or OMNI-processing of a given listening environment produced a closer match to a reference template representing clean speech. The template is the output of an auditory processing model that characterizes the spectral and temporal modulations associated with a given input signal (clean speech in this case). A modified version of the spectro-temporal modulation index (mSTMI) was used to compare the template to both DIR- and OMNI-processed versions of a given listening environment, as processed through the same auditory model. These analyses were carried out on recordings (originally collected by Walden et al, 2007) of OMNI- and DIR-processed speech produced in a range of everyday listening situations. Walden et al reported OMNI/DIR preference judgments made by raters at the same time the field recordings were made and judgments based on laboratory presentations of these recordings to hearing-impaired and normal-hearing listeners. Preference predictions based on the mSTMI analyses were compared with both sets of preference judgments. Results: The mSTMI analyses showed better than 92% accuracy in predicting the field preferences and 82–85% accuracy in predicting the laboratory preference judgments. OMNI processing tended to be favored over DIR processing in cases where the analysis indicated fairly similar mSTMI scores across the two processing modes. This is consistent with the common clinical assignment of OMNI mode as the default setting, most likely to be preferred in cases where neither mode produces a substantial improvement in SNR. Listeners experienced with switchable OMNI/DIR hearing aids were more likely than other listeners to favor the DIR mode in instances where mSTMI scores only slightly favored DIR processing. Conclusions: A direct-comparison approach to OMNI/DIR mode selection was generally successful in predicting user preferences in a range of listening environments. Future modifications to the approach to further improve predictive accuracy are discussed.

scholarly journals Audibility Problems with Fire Alarms in Apartment Buildings

1995 ◽  
Vol 39 (15) ◽  
pp. 989-993 ◽  
Author(s):  
Guylène Proulx ◽  
Chantal Laroche ◽  
John C. Latour
Keyword(s):  
Fire Safety ◽  
Movement Time ◽  
Subjective Assessment ◽  
Sound Level ◽  
Building Evacuation ◽  
Fire Alarm ◽  
Apartment Buildings ◽  
Evacuation Drills ◽  
Audio Tape Recorder ◽  
The Impact

A previous study of apartment building evacuation drills showed that as many as 25% of the occupants mentioned not hearing the fire alarm from inside their apartments. A new experiment was developed to observe evacuation drills and to measure the sound level of the fire alarms in three high-rise apartment buildings. These buildings, built during the 1980's, met the local building regulations regarding the provision of fire alarms at the time of construction. Each building contained approximately 200 apartments, with 1 to 4 persons per apartment. For each building, the printed fire safety procedures stated that all occupants should leave the building or move to an area of refuge, upon hearing the building fire alarm. During each evacuation drill, video cameras, were located in corridors and staircases, to record the movement time and behaviour of occupants. Using a digital audio tape recorder, precise sound samples of the fire alarm and background noise were taken from different locations in the buildings. Analyses of the alarm sound spectrum and levels were performed. Results confirm the subjective assessment of occupants who mentioned not hearing the fire alarm in specific locations of the building. It was also found that, in some other areas, the alarm was overpowering. The impact of alarm audibility on fire safety is discussed.

scholarly journals Predicting the Perceived Restorative Potential of Bird Sounds Through Acoustics and Aesthetics

2018 ◽  
Vol 52 (4) ◽  
pp. 371-400 ◽  
Author(s):  
Eleanor Ratcliffe ◽  
Birgitta Gatersleben ◽  
Paul T. Sowden
Keyword(s):  
United Kingdom ◽  
Sound Level ◽  
Acoustic Properties ◽  
Regression Analyses ◽  
Restorative Environments ◽  
Online Study ◽  
Natural Stimuli ◽  
The United Kingdom ◽  
Objectively Measured ◽  
Shed Light

Some, but not all, bird sounds are associated with perceptions of restoration from stress and cognitive fatigue. The perceptual properties that might underpin these differences are understudied. In this online study, ratings of perceived restorative potential (PRP) and aesthetic properties of 50 bird sounds were provided by 174 residents of the United Kingdom. These were merged with data on objectively measured acoustic properties of the sounds. Regression analyses demonstrated that sound level, harmonics, and frequency, and perceptions of complexity, familiarity, and pattern, were significant predictors of PRP and cognitive and affective appraisals of bird sounds. These findings shed light on the structural and perceptual properties that may influence restorative potential of acoustic natural stimuli. Finally, through their potential associations with meaning, these findings highlight the importance of further study of semantic or meaning-based properties within the restorative environments literature.

scholarly journals Acoustic and Flow Aspects of Novel Synthetic Jet Actuator

Actuators ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 100 ◽  
Author(s):  
Emil Smyk ◽  
Paweł Gil ◽  
Rafał Gałek ◽  
Łukasz Przeszłowski
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Optimal Solution ◽  
Sound Level ◽  
Pressure Level ◽  
Synthetic Jet ◽  
Acoustic Properties ◽  
Synthetic Jet Actuator ◽  
Flow Parameters ◽  
Level Meter

The acoustic and flow aspects of the novel synthetic jet actuator (SJA) with fins inside the cavity were experimentally investigated for three types of enclosure design and two models of loudspeaker. The aim of the study is to find the parameter which connects the flow and acoustic properties of the SJA and allows us to choose the optimal solution in those regards. The hot wire anemometry was used for the velocity measurements and the sound pressure level was measured with a sound level meter. The model of the loudspeaker turned out to have a significantly stronger impact on the flow parameters and noise level than the shape of the fins in the cavity. The parameter that showed a dependence on the shape of the fins was the actuator’s efficiency. A ratio of the root-mean-square velocity at the orifice axis to the sound pressure level (U0.c/SPL) was used to connect the acoustic and flow properties of the tested actuators. This parameter was subsequently applied to determine the best configuration among the tested actuators.

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