NEC Acostix. Sound Attenuation Calculations and Design Software. General Information

Transcription

1 NEC Acostix Sound Attenuation Calculations and Design Software General Information

2 NEC Acostix TM is an Excel-Based programmable sheets to help engineers and manufacturers design acoustic enclosures, rectangular silencers, acoustic louvers or do noise calculations to verify their selected designs. To get a quote please complete the form and submit. You can contact us on support@najahengineering.com for further details. See also our 2015 Price List NEC Acostix TM gives best estimates for the sound insulation performance of the walls, silencers and louvers depending on the supplied data and acoustic material properties. Acostix TM is registered as a trademark in the ministry of industry & trade in Amman - Jordan under no General Features: All sound calculations meet international standards ASTM E90, ASTM E477, ISO 7235, ISO 3741, ISO 140, ISO 3744, ISO 3746, ISO 6798, ISO , ASHRAE Handbook, Sound Research Laboratory, etc. Calculates the required silencer attenuation to meet noise criteria. Verifies any selected silencer to meet the noise criteria. Design acoustic wall or partition to meet certain SRI or certain noise criteria Change the wall or partition steel thickness, acoustic filling properties and perforation geometry and see the effect on the noise attenuation Takes into consideration free field and reverberant rooms situations. Design rectangular attenuators by allowing you to flexibly adjust all design parameters such as overall aperture size, number of splitters, splitter thickness, air gap between splitters, acoustic filling acoustic properties, perforation sheet configuration, air way length, air flow, flow velocity, etc It uses latest algorithms to predict the performance of splitter duct silencers acoustical performance. Takes into consideration inlet air temperature and temperature rise inside enclosures. It differentiates between inlet and discharge air sound attenuations by considering the regenerated noise. It calculates pressure drop across all air inlet and discharge attenuation systems. Design acoustic louvers by allowing you to flexibly adjust the louver depth, louver blade shape, and louver blade thickness, air gap between blades, louver depth, louver acoustic filling properties and perforation sheet. It allows also adjusting the free area percentage and airflow velocity. It will provide the insertion loss for the designed attenuator and sound transmission loss for the louvers. The software helps to calculate the best perforation that can achieve best acoustic results. 2

3 The software can estimate diesel engine exhaust noise, surface noise and air flows if not known. The software calculates any noise in free filed or inside reverberant rooms either as a single noise figure or over the octave band. The software is equipped with a tool to calculate the wall or partition SRI (TL) The software is equipped with a tool to calculate average room absorption coefficient over octave band. The software is equipped with a tool to calculate pressure drops for different duct configurations and elbows. NEC Acostix Modules: AX-C : Acostix all modules. Only from 2015, this shall include the following modules: AX-01, AX-02, AX- 03, AX-04, AX-05, AX-06 and AX-07. This is a very power tool for designers of enclosures, attenuators, partitions, louvers and silencers (1) plus they can do sound calculations inside and outside rooms/enclosures. AX-01 : Acostix Exhaust silencing module (first license). This module enables you to find suitable muffler insertion loss for a certain engine if you know the engine un-damped exhaust noise SPL or SWL and your acceptance criteria for example: 85 dba at 1 meter AX-02 : Acostix Wall / Partitions Design (TL/SRI) Module. This module enables the designer to select the wall/windows/doors configuration and get individual transmission loss or overall transmission loss. In 2005 versions double-plate structures will be added. AX-03 : Acostix Duct Attenuator Design Module. This enables the designer to specify the dimensional details and acoustic materials specs of the attenuator to get the insertion loss (SIL/DIL). You can also simulate both friction and dynamic pressure losses through the duct. AX-04 : Acostix Acoustic Louvers Design Module. You select one of five different louver configurations, specify the dimensional details and acoustic materials and then get the transmission loss (TL) and Noise Reduction (NR) along with simulated pressure loss. AX-05 : Acostix Genset Acoustic Enclosure/Canopy Design Module. Enter the SWL/SPL, dimensional details of enclosure, dimensional details of engine box, engine airflow data, specify inlet and discharge dimensional details, doors and windows. The module will give the enclosure wall SPL at the specified locations. AX-06 : Acostix HVAC Acoustics Module. Enter the HVAC duct layout and dimensional and acoustical details, AHU fan SWL and the NC at the recipient room. The module calculates the sound attenuation required that can be achieved either by a sound attenuator or by increasing the lining of the ducts. 3

4 AX-07 : Acostix Sound Calculations Module. This includes free field and inside rooms sound calculations, room average sound absorption coefficient, pressure drop for extended ducts and SPL/SWL/Air flow estimator for industrial machines. (1) Exhaust Silencers design is not yet included in AX-C module. This may be available in future versions Wall/Noise Barriers Design and SRI Calculations Tool This sheet calculates the overall SRI (TL) of an acoustic wall or barrier, that may contain doors and windows. The sheet enables you to select the windows and doors dimensions, Windows glass and thickness configuration. You need to enter the wall, door and windows dimensions. Then the sheet will calculate the overall SRI of the assembly. This SRI can then be used as a known SRI Value to complete the wall design for enclosure or rooms as stated in wall design sheet above. Acoustic Enclosure / Canopy Design for Diesel Generator Sets: This module designs the acoustic enclosure for diesel generators applications to meet certain noise rating or criteria. The module is fed with the engine noise data and then the designer will select the dimensional parameters of the wall, windows, inlet/discharge attenuation, and exhaust silencing to meet the criteria. The module allows you to enter either SPL or SWL data. You may also select between baffle type attenuators and acoustic louvers for inlet and discharge aperture attenuations. All design parameters and results are watched instantly at the same time on the same page for all parameters. By clicking a simple button, the module allows you to see the detailed calculations for all results if wanted. 4

5 Exhaust Noise Silencing and Calculations: This design sheet enables to do either do the exhaust noise calculations to find the optimum exhaust silencer attenuations (db's) at all 8 frequencies, or if you have a silencer with a known db's you can verify if it suites your diesel engine. Of course, you have to define criteria such as 90 dba at 1 m or 75 dba at 7 m and so on. You have to have the engine exhaust noise SPL or SWL data from the engine manufacturer. If not known then you can use the exhaust noise estimator, which is part of NEC Acostix to get the engine exhaust noise. If the engine is inside a room or enclosure with reverberant characteristics then you need to enter the room dimensions. To be much more precise you need to enter the average sound absorption coefficient of the room internal walls. If not known to you then you can use the absorption coefficient calculator to find them. At the end, the software will give you the results and summary of all calculations. You can always hide or show this calculation for the purpose of submittal to your customers. Inlet/Discharge Attenuators Design & Calculations: This is a powerful design sheet, which does two things at the same time. It designs the rectangular attenuator by finding its dimensional parameters and acoustic characteristics to achieve the noise attenuation from one side and it gives the dimensional parameters that achieve maximum allowable pressure drop across the attenuator air ducts. The sheet can do 4 functions: design inlet attenuator, design discharge attenuator, verify inlet attenuator and verify discharge attenuator. You need to enter the engine surface noise SPL data, airflow data, noise criteria; overall aperture height and width and then you select the number of airways and the thickness of the splitters. Of course there are rules how to select them which you can learn in our noise. You can fine-tune your selection to get the best results of acoustic and pressure drop performance. You can always select to show or hide the detailed calculations. The sheet allows you to select the acoustic materials filling details and enter the average room absorption coefficient, which can be calculated by NEC Acostix. 5

6 Acoustic Louvers Design and Calculations: Similarly this design sheet enables to design the acoustic louvers to achieve the required acoustical and airflow performance. You can select either to design inlet or design discharge louvers. You can select among 5 different louver shapes. Other configurations can also be added upon request. You have to enter the noise source SPL/SWL. You need to enter the selected acoustic filling materials absorption coefficients and thickness. You need also to select the perforation configuration. You have to specify the noise criteria and distance. You can select if the room is reverberant or not and accordingly enter the absorption coefficient data, which can also be calculated by NEC Acostix tools. Then you can choose your design parameters. Louvers blade thickness, Louver depth, louver blades spacing and free area percentage of the overall aperture. The software will display the resultant noise and air pressure drop for the selected design. You can fine-tune your design parameters to optimize the results. Of course you can select to show or to hide the calculations before you print the report. Cover Sheets Perforation Configurations and Calculations: These tools enable you to find the Transparency Index (TI) and the open area percent of the perforated sheet used to cover the acoustic materials used in air ducts. These two parameters affect the acoustic performance of the perforated sheet and therefore affect the overall acoustic performance of the air duct assembly. Of course, the higher the TI the better it will be for the noise absorption of the acoustic filling but this may not be possible due to the perforation sheet mechanical characteristics and strength. You enter the perforation geometry and the sheet will calculate the TI and P. These two parameters are inputs to the design of the walls, attenuators and louvers. The resultant of this sheet are the TI, P and the access factor, which will be multiplied by the absorption coefficient of the acoustic material. In other words, this access factor downgrades the acoustic materials sound absorption capability. 6

7 Engine Exhaust Noise/Surface Noise and Air Flow Estimator: This tool enables the designer to estimate the engine exhaust noise SPL or SWL, engine surface noise SPL and the inlet and discharge airflow. You just enter the engine KW and then select from the drop down lists different characteristics of the engine, which must be known if the engine is physically available. The software will display the engine exhaust and surface noise data over the 8 frequencies and the inlet and discharge air flow. These results can be used to design walls, attenuators and louvers if the data is not available from the manufacturer. Free Field / Inside Rooms (reverberant) Noise Calculations Tool: Sometimes you may need to calculate the noise in the free filed if the noise is knows at some location. This sheet allows for noise calculations of SPL or SWL at different distances in the free field. You can either do the calculation for a single db figure or over the Eight (8) frequencies. SPL vs SWL: The difference between SPL and SWL: SPL is the sound pressure level =20 log P/Pref. Pis sound pressure in N/m 2 and Pref = 20 x 10-6 N/m 2, while SWL is sound power level = 10 log W/Wref, where W is sound intensity in Watts and Wref = Watt. The sound is is coming out from the source as SWL and when it travels spherically its intensity will be distributed over sphere area which makes it pressure SPL. You may also need to do calculations of noise inside the room if the noise source is placed at certain distance and you need to measure noise at certain point inside the room taking into consideration the reverberation time of the room. This tool does this. You can do this as a single figure or you can enter the noise data of the source in SPL or SWL over the octave band, and enter all other details of the room. The resulting information will be the noise level at the point you selected. You can select to show or hide the calculations before printing the report. 7

8 Average Room Absorption Coefficient Calculations Tool This tool helps designers calculate the room average sound absorption coefficient over the octave band. The sheet allows to enter the room dimensions, and from the drop down lists one may select the sidewall, end walls, roof and floor material. The results of this sheet will be the average absorption coefficients and the reverberation times. These results are very valuable when calculating sound from inside rooms through walls, attenuators and louvers. Pressure Drop Calculator Tool: This sheet helps gives the pressure drop across different duct systems, which you may choose from the drop down list. It helps when sometimes the inlet air or the discharge air needs to be ducted 45 degrees or 90 degrees for some distance. 8

9 Training and Technical Support: You can attend the following courses that will enrich your knowledge and skills in industrial noise control and sound attenuation design: AC-01 Industrial Noise Control and Sound Attenuation Design Five (5) days course organized publicly or in-house. This is 30 hours of training instruction and Extensive design workshops covering all the concepts of noise, sound insulation materials and Design of noise control modules for power generation, residential, HVAC and other applications AC-04 NEC Acostix Software training course. This is a two (2) days course that explain the fundamentals of acoustics and then go through the Acostix software modules with examples You can register in any of the training courses online by visiting our itd website For technical support, you may contact support@najahengineering.com 9

10 END USER AGREEMENT Copyright (c) Najah Engineering Consultants LLC END-USER LICENSE AGREEMENT YOU SHOULD CAREFULLY READ THE FOLLOWING TERMS AND CONDITIONS This End-User License Agreement for NEC Acostix software ("SOFTWARE PRODUCT") is a legal agreement between you (either an individual or an entity) and Najah Engineering Consultants LLC Team ("AUTHOR"). You agree that your use of the SOFTWARE PRODUCT acknowledges that you have read this license, understand it, and agree to be bound by its terms and conditions. IF YOU DO NOT AGREE TO THE TERMS AND CONDITIONS OF THIS LICENSE AGREEMENT, DO NOT INSTALL AND/OR USE THIS SOFTWARE. 1. LICENSE GRANT: The SOFTWARE PRODUCT is licensed, not sold, to you by AUTHOR for use only under the terms of this License, and AUTHOR reserves any rights not expressly granted to you. 1.1 LICENSE TYPES AUTHOR provides the following types of licenses - EVALUATION LICENSE (TRIAL MODE) and SINGLE USER BUSINESS LICENSE. Before purchasing a license, you may have to install the trial version of the SOFTWARE PRODUCT and verify that the SOFTWARE PRODUCT is working correctly and as expected on your computer. With the SINGLE USER BUSINESS license, you are granted a full working copy of the software for limited or unlimited period of time depending on what you purchased. 1.2 EVALUATION LICENSE ENTITLEMENT The EVALUATION LICENSE ENTITLEMENT only applies when you obtain a copy of the SOFTWARE PRODUCT for the first time. You may use the Evaluation (Trial) Version of the SOFTWARE PRODUCT for a certain number of days evaluation period. After the evaluation period, if you want to continue to use the SOFTWARE PRODUCT you must purchase the required number of Single User Business Licenses and remove the trail version software from your computer. Packages created with the SOFTWARE PRODUCT under EVALUATION LICENSE CANNOT be used for commercial purpose. 1.3 SINGLE USER BUSINESS LICENSE ENTITLEMENT AUTHOR grants to you a personal, non-transferable and non-exclusive right to use the copy of the SOFTWARE PRODUCT provided with this License. The SINGLE USER BUSINESS LICENSE authorizes you to use one copy of the version of the SOFTWARE PRODUCT on a single computer. Packages created with the SOFTWARE PRODUCT under SINGLE USER BUSINESS LICENSE can be used for commercial purpose and contain the references to AUTHOR and SOFTWARE PRODUCT. You are NOT authorized to use our product as a SERVICE to a third party developers. 2. ORDERING How to order the license, you can find out on Najah Engineering Consultants LLC web site 3. NO REFUND No refund is given at any time, unless authorized by the AUTHOR under unexpected circumstances. The AUTHOR reserves the right to provide refunds, or make any commercially reasonable efforts to solve any issues at his discretion. Please contact the AUTHOR to see if you qualify for a refund. 4.DISCLAIMER OF WARRANTY AND LIABILITY THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS. AUTHOR DISCLAIMS ALL WARRANTIES RELATING TO THIS SOFTWARE, WHETHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. NEITHER AUTHOR NOR ANYONE ELSE WHO HAS BEEN INVOLVED IN THE CREATION, PRODUCTION, OR DELIVERY OF THIS SOFTWARE SHALL BE LIABLE FOR ANY INDIRECT, CONSEQUENTIAL, OR INCIDENTAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE SUCH SOFTWARE, EVEN IF AUTHOR HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES OR CLAIMS. THE PERSON USING THE SOFTWARE BEARS ALL RISK AS TO THE QUALITY AND PERFORMANCE OF THE SOFTWARE. 5. EXCEPTIONS No exceptions to any portion of this license agreement will be allowed without the express written permission of AUTHOR. If you have any questions about this Agreement or the Software, feel free to contact us at: Support@najahengineering.com 10

11 Acostix Trade Mark Registration 11