PAGA Coverage Study

Our engineers are acutely aware of the importance of building a reliable, fail-safe, and highly intelligible PAGA system. The selection and placement of loudspeakers are meticulously planned by qualified and competent sound experts. You will enjoy a quality system that will produce high speech intelligibility over the entire facility. Using state-of-the-art computer modelling software to predict the surrounding ambient noise and reverberation effects of nearby structures. Our renowned capability in providing the most comprehensive coverage study for PAGA has put us at the forefront of the competition.

Objectives

• Perform acoustic study in full compliance with the industrial Standard
• Identify potential sources of high ambient noise and determine the correct position of field equipment for PPS within the plant area and perform noise mapping.
• Verify and evaluate the existing speakers’ sound coverage for PPS and identify the non coveredarea in the plant area as per the latest approved plot plan to ensure that personnel in the intended reception area can receive and recognize an alert and voice message.
• Based on existing speakers’ sound coverage analysis, provide optimum speaker location and quantity to achieve optimum and proper sound coverage as per industrial standards and industry best practices.

Method of statement

• Before conducting the site survey collect all the necessary drawings and documents such as plant layout drawings, existing speaker position drawings, speaker installation height, tilt, azimuth, etc.
• Identify  the  actual  position  of   the plant  layout  drawing  and  measure  the  average ambient noise using an accurately calibrated dB Meter.
• Repeat the average ambient noise measurement and plot the measured  noise in  the layout drawing. Take the more dense measurement in highly noisy areas.
• Identify nearby acoustic obstacles such as structures, buildings, tanks, etc.  , and measure its typical height.  Record the identified obstacles and its type, height, etc in the plant layout diagram.
• Verify the existing speakers’ location and its  azimuth,  installation  height  , etc  with  the given details
• Gather all  other  related  informations  like  average  ambient  temperature,  humidity,  wind direction & speed, and existing structure elevation.
• Transfer the plant layout diagram into CadnaA tool along with the details of the obstruction such as building, tanks, structures, and its typical height CadnaA tool.
• Transfer the existing speaker details such as its position, spear power, installation height, tilt, and azimuth to the CadnaA tool.
• Transfer the measured average ambient noise details to the cadnaA tool.
• Simulate the CadnaA tool for the average ambient noise plot and save the result to the grid, Simulate the CadnaA tool for the existing speaker coverage plot and save the result to the grid.
• Simulate  the  CadnaA  tool  for  Auditability  by  performing  the arithmetic  operation  and  saving  the result  to  the  grid.  Compare  the  generated  auditability  plot  with  SEC,  NFPA,  and ISO  standards, and  its  requirement.  If  the  result  is  not  meeting  the  SEC,  NFPA  requirement,  simulate  the CadnaA  tool  by  changing/adding  speakers  and  its  position  to  get  optimum  coverage  to  the entire EG2 area.

Ambient Noise Monitoring Equipment     

Extech  407730  digital  sound  level  meter  was  utilised  for  the  measurements.  The  sound  meter  can measure  sound  pressure  levels  varying  from  40dB  to  130dB  maximum  with  an  accuracy  of  2 dB.  It supports both A weighted and C weighted measurement, fast and slow response, Max hold capture for  heights  reading  and  graphical  display.  The  sound  level  meter  was  calibrated  regular  period  of intervals.

The  ambient  noise  measurements  were  carried  out  in  an  approximate  grid  format  in  order  to establish the spatial variation of noise levels in each plant area. The measurement grid resolutions of  ambient  noise  measurement  were  varied  based  on  the  ambient  noise  level  and  density  of equipment  deployed.  Where  ambient  noise  levels  ranged  from  55  –  70  dB(C),  noise measurements  were  taken  at  approximately  30  metre  intervals.  Where  ambient  noise  levels  were higher  than  75  dB(C),  noise  measurements  were  taken  approximately  20  metre  intervals.  The ambient  noise  levels  measured  in  the  EG2  plant  area  ranges  from  a  minimum  of  70  dB(A)  to  a maximum of 103 dB(A).

Tool we use for modeling

What are included in our report

In order to establish the operational coverage of the in-plant paging system within the EG1 plant area, the  internationally  recognized  noise  modelling  software  ‘CadnaA’  has  been  utilized.  CadnaA  meets the requirement for Quality Assurance of software for the calculation of sound outdoors according to DIN 45687 and ISO 17534 series.

CadnaA is  perfect  tool  for  design  of  Public  Address  and  General  Alarm  (P.A.G.A.)  Systems  in industrial  sites  or  even  dams,  where  certain  noise  levels  must  be  assured.  Such  a  project  needs specific requirements:

• First, verbal announcements and alarms transmitted via the loudspeakers shall have a sound pressure level above background noise for a defined value.
• In addition, as specific loudspeakers are used, the sound pressure level at the listener should not be greater than a defined level above the background noise to avoid hearing problems to the listeners.
• Paging system Modelling and Assumptions

The following input data are used for acoustics modelling of the in-plant paging system.

 Average Ambient Noise Analysis

In Ambient noise analysis, as mentioned Method of statement, all the measured actual noise is transferred to the CadnaA tool. Simulated output is saved to the grid. This ambient noise grid map is used for Auditability by performing the arithmetic operation.  The simulated output  of  the  average ambient noise measured is shown In the figure

Speaker Sound Propagation Analysis

In this  stage,  existing  speaker  details  such  as  Speaker  power,  octave  band,  installation  height, azimuth,  tilt;  and  obstructions  such  as  buildings,  structures,  tanks;  and  reflection  parameters, ground absorption coefficient, meteorological data etc. are transferred to the CadnaA tool. The grid map calculation was then carried out at a resolution of 5 meters to simulate the approximate sound levels achieved by the speakers  in  the  study  area.  The simulated output for speaker sound propagation is saved to the grid and is depicted in the figure

Auditability (Coverage Analysis)

In this stage, CadnaA uses the two previously simulated outputs (Speaker sound output and average ambient noise output) and perform arithmetic  operation.  The result of the arithmetic operation  gives auditability, as shown in the figure.

ACOUSTIC COVERAGE STUDY

Aarmtech Acoustic study service is available to enable the project to predict broadcast system performance. The study is executed based on a site survey, where actual broadcast versus ambient noise sound pressure level readings are recorded and mapped onto area plot plans. For green field sites, the acoustic coverage study can be implemented from data derived from ambient noise predictions. In either case, the field equipment is then specified in terms of type, quantity, orientation, frequency response, and power output.

The System performance criterion includes intelligibility of speech, speech/alarm tone audibility, and broadcast clarity, in each case with the coverage area envelope defined by the client.

In order to execute an acoustic study we require some basic information from the client:- Scaled plot plan and elevation drawings generated in Auto CAD, area classification i.e. Safe area, zone 1 and zone 2 potentially explosive hazardous area, performance basis for study – Broadcast audibility and/or intelligibility. The coverage envelope required detailing escape routes, muster areas, and critical locations. Finally, ambient noise predictions for each area of the site can be in the form of contoured maps, spreadsheet analysis, software-generated files, or spot ambient noise data given at strategic locations. Where the client has no knowledge of the ambient noise then Aarmtech is able to deliver a solution based on our nominated ambient noise estimates from our extensive experience of similar sites.

Output from the acoustic study

A graphical illustration of system broadcast performance is overlaid onto the client project plot plan drawings, this shows coverage sound pressure level gradients from each loudspeaker and signal to ambient noise maps (relative levels above the ambient noise levels measured or predicted). Each device is uniquely tag numbered with the following data appended – power setting, type of loudspeaker (i.e. horn-loaded, direct radiator, explosion proof or safe area) alignment. The study considers compartment footprint and height, dividing walls, target listening area, location, and quantity of devices. A detailed report is delivered which contains the design input data, the basis for the study, rules/specifications (where applicable), and output data i.e. quantity of field devices, location, and type. The report details the predicted performance of the system and compliance with specifications/standards plus any corrective actions.

If you have any question about Acoustic study service or would like to request a quote, you can reach us by email, phone or by filling out the contact form, our dedicated team of Acoustic study will get back to you as soon as possible, We look forward to hearing from you

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