Sound is created by a source, is transmitted by come path, and is received by the occupants of the space.

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2 All about Sound Control Sound control, the creation of an acoustical environment compatible with the intended function of e room or space, is an important part of building design. Today it ranks equally with creation of a proper thermal and luminous environment. Sound is created by a source, is transmitted by come path, and is received by the occupants of the space. Sound control is an important factor in the design of air distribution system. Most noise is created by the fan used in air conditioning system. The amount of sound reaching the occupied spaces depends on the fan s sound generation characteristics and duct system (supply and return) sound attenuation. Therefore, both supply and return system must be evaluated to provide optimum sound control. GOLDENSTAR joint hand with Tempmaster Corporation USA will be pleased to assist in the solution of your noise problem and will design and manufacture noise control devices to your specific requirements. Do you have a noise problem? Let us have it! and we will do our utmost to keep it quiet. Air Cushion Principle tunes out Low Frequency Fan Noise Conventional noise absorption methods dissipate sound by passing air molecules through glass or mineral wool fibers. This method is most effective for high frequencies where sound weves ere short. For maximum effectiveness in low frequencies, impractical thicknesses of absorbing material ere required. Air Cushion absorption principle. The Air Cushion provides efficient noise reduction in low frequencies, bringing the most severe fan noise problems to within acceptable NC limits. Optimum Economical! Performance, Yet The Air Cushion principle utilizing specially designed, foil kraft laminated, fiberglass construction decreases the effective speed of sound and associated wave lengths by e factor of 2. Therefore, low frequency noise absorption performance can be obtained with one-half the thickness required by conventional methods. The dashed curve shows typical fan noise after attenuation by conventional perforated faced porous fiber absorbers. This\ method is ineffective in low frequencies, and gives more attenuation than is needed in high frequencies where fans produce relatively less troublesome sound. The solid curve shows typical fen noise after attenuation by Acoustic-Cells utilizing the

3 The most modern GOLDENSTAR Airflow and Acoustic Lab, designed and built in accordance to ISO standard prov ide guaranteed perf ormance of GOLDENSTAR acoustic products. The measurements are controlled and superv ised by a computer-based measurement collection system. The measurements are easily controlled as the measurement results are continuously shown in graphics. ACOUSTIC ANALYZER / INSTRUMENT PANEL GOLDENSTAR CUSTOMER TAGNO TITLE FAN DUTY PRESSURE SSCL SA-03S PAC x 800x 600mm 2.85 M'/S 7.50 Pa LICENSE TO PROJECT NAME DATE FAN TYPE SYSTEM K.A.A.U. JEDDAH 26/08/97 SHEETNO:1 SUPPLY OCTAVE CENTRE FREQUENCY, fm Hz K 2K 4K 8K IN DUCT SOUND POWER db TYPE DIMENSION LENGTH RECTANGULAR DUCT RECTANGULAR DUCT RECTANGULAR DUCT ROUND DUCT RADIUSED BEND RADIUSED BEND RADIUSED BEND RADIUSED BEND OUTLET REFLECTION 1500cm TOTAL DUCT ATTENUATION SWL LEAVING SYSTEM PERCENTAGE LEAVING OUTLET 10% OUTLET DISTANCE TO LISTENER 2.00 m DIRECTIVITY TYPE C S 9 TOTAL DIRECT FACTORS DIRECT SPL PERCENTAGE REACHING ROOM 100% ROOM VOLUME 621 m REVERBERATION TIME 0.50 sec TOTAL REVERBERANT PRESSURE LEVEL REVERBERANT SPL COMBINED SPL CRITERION NC REQUIRED INSERTION LOSS + 3dB db ** ** SELECTED INSERTION LOSS db REVERBERANT ROOM Sound measurements are made in a rev erberant room with most modern equipment f rom Bruel & Kjaer. Rev erberant room constructed in accordance to ISO standard, f ully isolated f rom factory f loor to keep background noise as minimum as possible. ACOUSTIC AN ALYSIS SAMPLE REPORT No Guess work! No matter what type of room construction, f an noise, duct lay out and noise criteria to be maintained in y our buildings, GOLDENSTAR powerf ul software dev eloped with latest ISO and ASHRAE recommendation, can tell you precisely how much insertion loss required f or y our sound attenuator to maintain design goal. 3

4 Complete Flexibility A wide choice of noise control products to your any specific application from one manufacturer. Whatever noise control requirements, GOLDENSTAR Acoustic products must fulfil, you can be sure there is an Air cushion Acoustic-cells equal to the task. In any size, configuration, and price change that is exactly right for you. º Square / Rectangular Model GTS GTF GTF-VB/FTF-HB Standard Acoustic cells Acoustic cells with perforated steel protection Bend Type º Round GTFR High db Attenuator with center pod Also available from Goldenstar - Acoustic Louvers - Acoustic - Tube silencers, for air transfer applications. (cross talk attenuator) - Acoustic - enclosure for generating sets. Table-l RECOMMENDED NOISE CRITERIA FOR ROOMS Type of Ares NC Level,Decibels Type of Area NC Level,Decibels AUDITORIUMS Concert and Opera Halls, Studios for sound Reproduction to 25 Legitimate Theaters, Multi-purpose Halls to 30 Movie Theaters, Lecture halls, Planetarium. TV audience studios to 35 Lobbies to 46 CHURCHES AND SCHOOLS Sanctuaries to 30 Libraries, Schools and Classrooms to 40 Laboratories to 45 Recreation Halls, Corridors and Halls to 50 Kitchens to 50 HOSPITALS AND CLINICS Private Rooms to 35 Operating Rooms, Wards...30 to 40 Halls and Corridors, Laborataties, Lobbies and Waiting Rooms to 45 Washrooms and Toilets to 50 RESTAURANTS AND LOUNGES Restaurants to 45 Cocktail Lounges to 60 Night Clubs to 45 Cafeterias to 50 SPORT ACTIVITIES INDOOR Coliseums to 40 Bowling Alleys, gymnasiums to 45 Swimming Pools to 55 TRANSPORTATION Ticket Sales Offices to 40 Lounges. Waiting Rooms to 50 HOTELS Individual rooms or suites, Ball rooms,banquet rooms. 30 to 40 Halls and corridors Lobbies to 45 Garages. Kitchens and Loundries to 50 MANUFACTURING AREA Foreman s Office..... A0 to 50 Assembly Lines, Light Machinery to 70 Foundries, Heavy Machinery to 75 OFFICES Board Room to 30 Conference Rooms to 35 Executive Office to 40 Supervisor Office, Reception Room to 45 General Open Offices, Drafting Rooms to 50 Halls and Corridors to 55 Tabulation and Computation to 60 STORES RETAIL PUBLIC BUILDINGS Clothing Stores, Department Storeslupper floors) to 45 Public Libraries. Museums, Court Rooms to 40 Department Storestmain floor).small Retail Stores. Post Offices, General Banking Areas, Lobbies to 45 Supermarkets to 50 Washrooms and Toilets to 50 4

5 Advanced design 1. Attenuator Casing 2. Acoustic Fill 3. Ceils Protection 4. Wedge Design 5. Straight-thru Air passage 6. Casing Seams 7. Cells - Beads 8. Flanges 9. Modular Construction 10. Optional Construction features Constructed from high quality galvanized steel of min. 22g. Moisture, Odor,Vermin, Fire and Erosion-proof Fibre glass laminated layers Air cushion. GTS-Aluminum Foil Kraft GTF-Galvanized Perforated steel over Acoustic Fill. Minimize air turbulence at intake and exit. Design minimize air pressure drop and maximum air handling capacity. Lock-formed or welded continuously and applied silicone sealant; Prevent air leak up to IO (250 Pa) static pressure. Optional heavy guage casing construction with welded seams available for higher static pressure application. Filled by silicone sealant; Minimize re-generated noise. 30mm Roll formed galvanized Doby slide flanges for attenuator cross section up to 3000mm (W +H), 40mm angle iron flanges (painted) over 3000mm (W + H) Attenuators are normally supplied in sections when any of the following dimensions are exceeded. W = 2500mm, H = I800mm, L = 3000mm Stainless steel casing MYLAR/MYLINIX Acoustic fill protection for clean room application. Epoxy paint coating for Corrosive air handling Heavier gauge casing construction. 5

6 Bend Attenuators Model - GTF-VB / GTF-HB The Construction of bend attenuators is generally as for the straight version. Dimension L, denotes the bend centre path length which is equal to the attenuator Length referred to in the various-.&election tables. Dimensions L1 and L2 refer to the air entry and discharge Legs respectively, measured along the outside of the bend. Unless requested otherwise, bend attenuators would be supplied with L1equal to L2. Bend attenuators can be designed for vertical or horizontal installation as shown below; to suit ductwork Layout, Air pressure drop of bend attenuators add 35% to the pressure loss, for the straight attenuator.

7 Table-2. Recommended 3rd band Attenuation(dB) for Quick Selection. Type of ventilated area being served by low velocity system Rooms with average Rooms with limited Rooms without soft finishing:floors carpeted furnishings: mainly hard furnishing, including: including: surface, including: Offices, Banks, Libraries, Hospital areas, Kitchens; Swimming Pools, High velocity CVlVAV Lecture rooms, Restaurants, Supermarkets, Computer Sports Halls, Covered systems incorporating Hotel rooms, Department rooms, Clean rooms, garages, Warehouses. terminal units. stores, Laboratories, Cafes, Dance Halls, Museums, Canteens, Toilets ) Fan Static Pressure 250Pa 500Pa 1000Pa 250Pa 500Pa 1000Pa 250Pa 500Pa 1 000Pa 2000Pa Max Attenuator Selection Procedure - GTS/GTF The following procedure allows quick selection of Sound attenuator. If attenuator performance requirements have been established by using Goldenstar computer Acoustic Analysis program, then proceed with Selection procedure described in step-3 onwards. However, to enable engineers for quick selections to assist in design planning, 3 rd band attenuation value required for various system and applicatioris has been devised in Table-2. It is recommended that Goldenstar engineers must verify such selections, when detailed system data is available. Any requirements for noise levels of below NC30 should be referred to Goldenstar for Acoustic Analysis and Computer Selection. Selection Procedure. 1. From Table-l,. select the recommended space noise criteria for the type of area concerned. 2. From Table-2, select recommended 3 rd band attenuation value for appropriate fan static pressure, noise criteria and type of area. 3. From Table-3, establish preferred duct width, #of cells and free area (Lower the percentage free area will give higher attenuation value). 4. Now from Table-4, select required attenuator length against free area to meet 3 rd band attenuation value established in Step Multiply selected 3 rd band attenuation value by using Octave Band Correction Factor Table-5 to have attenuation value for other bands. 6. Calculate the face velocity (in m/s) of selected attenuator by using following formula. Q/(WxH) = m/s Q - Airflow in m3/s W - Attenuator width in meters H - Attenuator height in meters 7. Pressure drop can be established by entering calculated face velocity in chart- 1. Draw a vertical straight line through face velocity until intersection with diagonal alignment line, then project horizontally to selected attenuator free area and read pressure drop in Pascals.(Pa.) Pressure drop to be corrected for selected attenuator length by using Table-6 factors. If pressure drop exceed to un acceptable level, increase the attenuator height and recalculate from Step-6 or increase the attenuator width and recalculate from Step-3 onwards until to miet all parameters. 8. Dynamic & Regenerated noise correction: Dynamic and regenerated noise correction in almost all cases, have very little influence in general performance and, therefore, may be ignored. However for critical application, these to be verified by using Chart-2 & Chart-3.

8 Selection Example. Given: 20dB 3 rd band attenuation required to maintain NC-40 in an office room, ducted system having, IOOOPa. fan static pressure, 1000 x 500 preferred attenuator size, 2.25m3/s airflow and IOOPa. pressure drop. Select: Attenuation, air pressure drop and length. Step-l Enter Table-3, check free area and #of cells against attenuator width 1 OOOmm. % of free area 70, 55, 40, 25 #of cells 2. 3, 4, 5 Step-2 From Table-4, select attenuator length to satisfy 20dB, 3 rd band attenuation. 25% 900mm 40% 1500mm 55% 2400mm 70% - not available Select any preferred length. All the above length will satisfy 20dB or more. Select 900mm 5 cells. Step-3 Using Table-5 Octave Band Correction Factors, find attenuation value of other bands. (Model GTF provide max. attenuation on all bands.) Octave Band Attenuation(dB) Step-4 Calculate the face velocity(m/s) of attenuator. Q/(1000x500) = 2.25/( 1.0x0.5) = 4.5 m/s Step-5 Find air pressure drdp of selected attenuator by entering in Chart-l, 4.5m/s 25% free area = 125Pa. Step-6 Correct pressure drop for selected using correction factor Table-6 125x0.8 = 100 Pa. Step-7 Find weight of selected attenuator. Enter Table-7, 900mm long and 5 cells Weight of IOOOmm width = 195kg (Interpolate between 900mm and 1200mm) Selection: Model - GTF Size-1000x500x900(WxHxL) Attenuation Air pressure drop Pa. Weight - 195kg. DYNAMIC CORRECTION REGENERATED NOISE The dynamic correction percentage is the increase or decrease in sound absorption due to flow of sound in the opposite o.r same direction as the flow of air. The percentage change in attenuation can be found from Chart-2 using the free area velocity(free area velocity = Airflow/Attenuator cross section X %free area). The correction increases the attenuation (added to) if the listener is on the return air side of the sound sound attenuator(difference attenuator and decrease the attenuation (subtracted from) if the listener is on the supply air side of the sound attenuator. 8 Regenerated Noise is sound caused by air motion in. the sound absorber. The amount of regenerated noise can be found by entering Chart-2 with free area velocity and reading up to System airflow. The: value found must be added logrithamically(see Chart-3) to the fan noise level obtained in the duct after the between fan sound power and absorber attenuation). In almost all cases, the regenerated noise level will be 10 db or more lower than the fan noise obtained after the absorber and, therefore, may be ignored. If the regenerated noise is too high, reselect the attenuator for lwer free area velocity.

9 Attenuators Selection Model - GTS/GTF Table - 3 Percentage Free Area: ATTENUATOR WIDTH # OF CELL / ACOUSTIC BAFFLE MM INCH ' ' Note: 1. Applicable for any Attenuator height. 9

10 Model - GTS/GTF Table - 4 Attenuation (db) at Different Length & Free Area:(3rd Band) % OF FREE ARE A ATTENUATION LENGTH (MM / INCH) ^ ;

11 Table-5 Octave Band Correction Factor: (Multiply 3rd Band value from Table-4 to find other Band value. FREQUENCY (Hz) K 2K 4K 8K OCTAVE BAND MODEL GTF GTS Note : For clean room application (MYLAR faced Attenuator), use GTS multiplier. Pressure drop Chart-1 are based on attenuator model GTF with 1200mm long. The following correction (Table-6) to be applied for other length or models Table-6 Air Pressure Drop Multiplier Attenuator Model Attenuator Length (mm) GTF GTS GTF-VB/GTF-HB

12 Table-7 Attenuator Weight - GTF Number of Cells Length Heiqht Weight.kg ±5% ,

13 CIRCULAR ATTENUATORS MODEL - GTFR CONSTRUCTION FEATURE OUTER CASING Constructed from not less than 1.0 mm. Galvanized mild steel sheet. Joints lockformed. º SOUND ABSORBENT MATERIAL Mineral wool protected by glass fiber tissue facing, In order to minimise frictional losses and prevent entrainment of fibers and particles. Acoustic fill of inert, non-hygroscopic, non-combustible and vermin proof. Packed to a density of not less than 70 kg/m3. Acoustic fill protected by a galvanized perforated steel. CENTER POD Constructed from not less than 1.O mm. Galvanized mild steel sheet, and perforated galvanized metal faced over acoustic fill. POD fitted with aerodynamically shaped leading edge for smooth air flow. º FLANGES Galvanized steel rings with tapped holes, to suite standard fan flanges. Casing peined over flange face. OPTIONAL EXTRAS º MYLAR FACED ~ACOUSTIC FILL FOR CLEAN ROOM APPLICATION. º EPOXY PAINT FINISH FOR CORROSIVE APPLICATION. 0 SPIGOT ENDS FOR DUCT CONNECTION. 13

14 PERFORMANCE DATA,_. DYNAMIC INSERTION LOSS (db) DIA(ID) LENGTH K 2K 4K BK 12 1D D D * D D D D D DIA SHOWN IN INCHES

15 NOMENCLATURE GTF (Model with perforated lining) GTS (Std. construction) GTFVB (Bend type vertical) GTF-HB (Bend type horizontal) GTFR (Round) Size (W x H x L) OPTIONS (Cell protection/coatings: M-MYLAR Faced cells S-Perforated stainless stl E-Epoxy painted O-Standard Casing type 0 - std. lock formed, GI 1 - welded casing, GI 2 - stainless steel stainless steel PVC casing SUGGESTED ENGINEERING SPECIFICATION General: The contractor shall furnish and install factory fabricated sound attenuators in the duct work that maintain all. acoustic and airflow criteria shown in this specification and schedule. The sound attehuator shall be model as manufactured by Goldenstar, K.S.A. Outer casing of the attenuators shall be constructed by 22 guge galvanized steel, lock formed and mastic sealed joints and shall be suitable for installing in duct system up to 10 inches wg.(2500 Pa.) positive pressure. Acoustic-cell shall be of the wedge design for low pressure drop and minimal noise generation. Acoustic fill shall be moisture-proof, odor-proof, vermin-proof, fire proof, erosion-proof. Air cushion multiple laminated layers, spring/mass tuned for low frequency absorption. Facing shall be reinforced aluminum / mineral fiber tissue and shall be retained in position by perforated, galvanized steel of minimum 24 guge, and shall be held in the frame with continuous beads of inert silicon sealant. Attenuator shall be fitted with roll formed 40mm Doby slide on flanges for cross section size up to 3000mm (W +H) and cold rolled steel angle end flanges drilled to a standard for larger size. INSTALLATION Sound attenuators shall be installed in the duct at a sufficient distance down stream of the fan or elbow to ensure uniform air velocity over both side of the unit. Down stream of a fan, attenuator shall be placed at least 4 duct diameters from the discharge opening and at a plane vertical to the fan shaft. Down stream of an elbow, the attenuator shall be placed 1 duct diameter from the end of the elbow and in the same plane as the turn. 15