---------------------------------------------------- Sound attenuator with recessed connection for rectangular ducts ---------------------------------------------------------------------- GENERAL is, due to its unique design with connection facing the side baffles, is suitable for use both in ducts and in direct connection to the air handling unit. QUICK FACTS Very compact rectangular attenuator Excellent aerodynamic characteristics Very low pressure drop through tapered splitters Environmentally friendly acoustic material, approved by independent test institute: CLEANOLON -AL Washable surface layer CLEANOLON -AL Available with inspection hatch Fire protected version with 50 mm mineral wool also available Connection dimensions from 400 x 300 to 2200 x 2200 Included in the databases Magic CAD and Point Registered design. The company reserves the right to make design changes without prior notice. 1
-------------------------------------------------------------- DESIGN is manufactured as standard in galvanized steel sheet. The sound attenuating material, CLEANOLON -AL, is tested to Swedish standard with regard to cleaning, fibreloosening, ageing properties, emissions, washable etc. is supplied as standard with C clip connection to connecting ducts. FUNCTION The low pressure drop in has been achieved by designing the splitter elements entirely according to the basic laws of aerodynamics. In order to further optimize the sound attenuator regarding pressure drop, some of the active components of the attenuator are located outside the connection position. This solution has contributed to increasing the set attenuation. The low pressure drop can be utilized for example to: reduce the space requirements through selecting a smaller attenuator decrease the pressure setting in the fan for the same size of attenuator minimize the inherent sound generation in the system due to lower velocities and reduced pressure setting facilitate adaptation of the attenuator to the connected duct system includes all the positive characteristics that Swegon earlier models have offered. By taking into account properties of the component materials and exploiting aerodynamic flow principles, Swegon has optimized the attenuator with regard to: acoustic properties of the sound attenuating materials. thickness of the splitters. width of the slots. length of the splitters. surface covering. By combining the above factors, Swegon can always offer the best sound attenuation and lowest pressure drop according to customer requirements. MAINTENANCE Under normal conditions is maintenance free. If the attenuator is required to be cleanable, it is possible to order with a factory fitted inspection hatch: see accessories. The inspection hatch reveals all the slots to achieve the best possible accessibility. It may however in many cases be advantageous to locate the inspection hatch in the duct adjoining the sound attenuator. ACCESSORIES T1: T2: T3: T4: Non-insulated inspection hatch. Fire-insulated inspection hatch. The sound attenuators is supplied fire-insulated with 50 mm mineral wool. N.B. The attenuator s H measurement is then increased by 100 mm. Perforated steel sheet covering of the insulation material. LOOSE SPLITTERS can be supplied as loose baffles without any housing. Please contact Swegon for further information. CUSTOMER MODIFICATIONS Besides the accessories and variants illustrated in the catalogue, it is always possible to make modifications. For example, can be ordered with lateral connection and horizontal splitters. Swegon, in consultation with a customer, can optimize the sound attenuator with respect to sound attenuation, size, adaptation to air handling unit and choice of materials (e.g. stainless steel, aluminium/zinc and etc.). For further information, please contact Swegon. PLANNING, GENERAL The TECHNICAL DATA shown here refer to the standard version of. Dampers, duct bends, and other equipment near the sound attenuator will increase the inherent sound generated in the attenuator as well as the pressure drop. The data shown are based on an even airflow in and out of the sound attenuator. See also the section on SYSTEM POWER and PRESSURE DROP. When the splitter surfaces are covered with perforated steel sheet, the inherent sound generated increases. See the section on INHERENT SOUND GENERATION. With a standard connection the total measurement of the sound attenuator is 200 mm more than the B-measurement. For special requirements the sound attenuator can be supplied for connection to its outer housing, in which case the B- measurement will remain the same as the attenuator s total width. See attenuator CADENZA. ENVIRONMENT "Environment declaration" is available on Swegon s website on the Internet or may be ordered from one of our sales offices. INSTALLATION The C-clip on this product are only intended for connection to ducts. The product is to be installed suspended with supports under its entire width. 2
PLANNING Dimensions/Sound attenuation 1. Calculate the required sound attenuation manually or with the aid of Swegon sound calculation software ProAc (available on our website). 2. Select the attenuator that can manage the calculated sound attenuation requirements for low frequencies (above all, 125 Hz) under TECHNICAL DATA. Also check the sound attenuation in the higher frequencies. 3. Check the H-measurement for the sound attenuator to optimize the pressure drop, also considering the system power. 4. The p-number obtained from TECHNICAL DATA is used to determine the pressure drop through the attenuator. The higher the p-number, the higher the pressure drop, see Nomogram 1. 5. Check the inherent sound generated in the attenuator. Pressure drop 1. Calculate the gross frontal area B x H (m 2 ). 2. Go to the relevant airflow in Nomogram 1. 3. Follow the line up vertically to the p-number obtained for the selected attenuator under TECHNICAL DATA. 4. Read off the pressure drop for duct-duct installation. 5. On selection of types of installation other than duct-duct, correct the pressure drop value with the aid of Graph 1. The pressure drop in Nomogram 1 is multiplied by the value obtained from Graph 1, depending on the installation of the attenuator. Example: A sound attenuator is located next to the air handling unit in a fan room. The airflow is 4 m 3 /s and the sound attenuator is mounted in a duct with a width of 1800 mm. The sound attenuator 1841 with a p-number of 3.2 has been selected from TECHNICAL DATA. The sound attenuator has a width of 1800 mm and is 600 mm high. The gross frontal area will be 1.08 m 2. Nomogram 1 shows a pressure drop of 26 Pa. If the sound attenuator had instead been duct-chamber mounted, the pressure drop would have been multiplied by 2.2 as in Graph 1. The pressure drop then obtained would have been 57 Pa. Nomogram 1. Determining the pressure drop Graph 1. Correction for other installations Curve 1; Chamber-Duct, Curve 2; Duct-Chamber Curve 3; Chamber-Chamber 3
-------------------------------------------------------------- SYSTEM POWER AND PRESSURE DROP Sound attenuator installed before or after a bend The corrections below must be multiplied by those in the graph showing pressure drop. Attenuator before bend: Attenuator after bend: Distance Corr.factor Distance Corr.factor 3xD 1,1 1xD 1,2 2xD 1,2 0 (direct) 1,3 1xD 1,35 0 (direct) 1,5 Sound attenuator installed before or after chamber The total pressure drop through the attenuator is obtained by multiplying the correction factor from Graph 1 by the pressure drop from Nomogram 1. Sound attenuator installed before or after a branch A sound attenuator installed after a branch is comparable to one installed after a chamber. See curve 1 in Graph 1. The total pressure drop through the attenuator is obtained by multiplying the correction factor by the pressure drop from Nomogram 1. Figure 1. Before or after a bend Distance refers to that between the sound attenuator and the bend, D refers to the largest side of the attenuator. Total pressure drop = attenuator pressure drop as in Nomogram 1 x correction factor. A sound attenuator installed before a branch is comparable to one installed before a chamber. See curve 2 in Graph 1. The total pressure drop through the attenuator is obtained by multiplying the correction factor by the pressure drop from Nomogram 1. Sound attenuator installed by an air handling unit It is difficult to obtain accurate corrections for a sound attenuator installed next to an air handling unit. This is mainly due to the variations in the fan outlet size between different manufacturers. The most common arrangement is a relatively small fan outlet (leading to high air velocities) combined with a large duct connection (with airflows of around 4-6 m/s). In general terms, the angle between the fan outlet and duct should not exceed 15. To ensure a good distribution of the airstream, a diffuser plate can be used with favourable results. Sound attenuator installed next to a damper A sound attenuator installed next to a damper can result in large pressure drops. As the damper angle increases there is a corresponding increase in the velocity profile spread. This leads to a greater air velocity between the attenuator splitters and thereby higher pressure drops. Sound attenuators connected in series When sound attenuators are connected in series, the basic principle is to avoid changes in the velocity profile between the connected attenuators. If the straight section between the attenuators can be made sufficiently long (4 x D), then in the best case the stated pressure drop per single attenuator will apply. One important aspect is also to ensure that the splitters in the attenuators do not cover other air slots. Please contact Swegon when connecting attenuators in series. 4
INHERENT SOUND GENERATION An attenuator does not only suppress sound, but also generates sound itself when there are high velocities and large pressure drops. There are normally no problems encountered as long as the recommended working range as shown in Nomogram 1 is observed. For accurate calculations there are curves marked in Nomogram 1 for inherent sound. Please use ProAc, in which we show pressure drop in addition to inherent sound levels. The L wt values given are sound power levels for with a reference value of 10-12 W for an airflow of 1 m 3 /s. By correcting L wt with K 1 for, the sound power level for each octave band is obtained. For with perforated steel sheet covering, first add 12 db to the indicated L wt value and then correct using K 2. Hz 63 125 250 500 1K 2K 4K 8K K 1-5 -5-9 -11-14 -17-18 -20 K 2-1 -2-10 -17-22 -24-25 -20 Corrections for airflows other than 1 m 3 /s are made by using Graph 2 below. Inherent sound generated must be 8 10 db lower in every octave band than the requirement for sound power level after the attenuator. Graph 2. Correction for other airflows Example: A sound attenuator is installed next to an air handling unit in a fan room. The airflow is 4m 3 /s and the sound attenuator is mounted in a duct with a width of 1800 mm. The sound attenuator 1841 with a p-value of 3.2 has been selected from TECHNICAL DATA. The height of 600 mm gives a gross frontal area of 1.08 m 2. Nomogram 1 gives L wt = 38 db. Correct with K 1 to obtain an octave band breakdown, and for 4 m 3 /s as in Graph 2: Hz 63 125 250 500 1K 2K 4K 8K L wt 38 38 38 38 38 38 38 38 K 1-5 -5-9 -11-14 -17-18 -20 4 m 3 /s 6 6 6 6 6 6 6 6 L w 39 39 35 33 30 27 26 24 5
-------------------------------------------------------------- TECHNICAL DATA B-measurement: 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1800, 2000, 2200 H-measurement: 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2200 B- and H-measurements in bold figures marked in yellow are standard. Total installation measurements in H plane: H+40 mm L-measurement: See the table in TECHNICAL DATA. Figure 2. INSPECTION HATCH In certain situations, requirements are placed on the attenuator being cleanable either through a hatch on the attenuator itself or in the duct next to it. The accessory T1 is available for with an inspection hatch that facilitates access to all air slots. The technical data are not affected when the accessory CAL- MO T1 is used. FIRE INSULATION In many cases the attenuator is installed in fire protected duct systems. When ventilation ducts are covered with fire protective insulation of 50 mm mineral wool, the sound attenuator may be externally insulated directly at site or in certain cases at the factory. This is available for as an accessory. There are two options: to only insulate the inspection hatch ( T2) or to insulate the whole attenuator ( T3). Technical data are not affected when accessories T2 or T3 are used. Figure 4. with 50 mm of mineral wool as fire protection Figure 3, with inspection hatch, T1 In those cases when is fitted with an inspection hatch, it is on the upper or lower surface of the attenuator (i.e. the B-measurement is defined as the width). When it is necessary to have the inspection hatch on the side, for example in confined spaces, the B-measurement will then be defined as the height instead (see above diagram). There must be enough space to open the hatch. The distance required for the fully open hatch is 700 mm. 6
TECHNICAL DATA B-measurement Code Length Static set attenuation (db) as in ISO 7235:91 P-value (mm) (mm) 63 125 250 500 1K 2K 4K 8K 400 0411 650 4 8 13 21 28 26 17 13 1.8 0421 1250 5 11 23 36 46 42 38 19 2.0 0431 1850 6 13 31 50 50 48 34 23 3.5 0412 650 5 10 15 22 27 26 16 14 4.0 0422 1250 7 14 24 36 45 40 24 18 5.0 0432 1850 10 17 32 49 50 45 32 21 8.0 500 0511 650 4 9 15 22 28 24 16 13 1.8 0521 1250 5 12 23 36 41 36 23 18 2.0 0531 1850 7 15 31 46 49 43 28 23 3.5 0512 650 6 10 16 25 30 29 18 14 4.0 0522 1250 8 16 26 39 46 41 28 20 5.0 0532 1850 10 20 33 48 50 46 35 26 8.0 600 0611 650 4 10 15 23 27 27 15 10 3.9 0621 1250 7 15 24 39 45 40 23 17 3.6 0631 1850 8 19 32 48 50 45 30 22 4.2 0612 650 4 8 12 18 22 20 11 8 1.3 0622 1250 5 12 19 32 37 31 15 11 1.7 0632 1850 7 15 26 44 48 38 19 16 2.7 0613 650 6 10 16 25 30 29 18 14 4.0 0623 1250 8 16 26 39 46 41 28 20 5.0 0633 1850 10 20 33 48 50 46 35 26 8.0 700 0711 650 3 6 9 14 18 16 8 5 1.2 0721 1250 4 10 16 28 33 27 9 6 1.4 0731 1850 5 12 21 42 45 34 12 10 1.9 0712 650 6 8 14 20 25 23 13 11 1.5 0722 1250 8 12 21 35 40 35 20 15 2.0 0732 1850 10 16 29 46 48 40 26 19 3.0 800 0811 650 4 9 14 21 27 26 16 14 1.8 0821 1250 6 13 23 35 45 40 24 18 2.1 0831 1850 7 16 31 48 50 45 32 21 3.5 0812 650 4 8 12 17 20 15 8 10 1.2 0822 1250 5 11 18 28 32 22 13 12 1.4 0832 1850 6 14 25 37 42 27 15 15 1.9 0813 650 5 10 15 22 27 26 16 14 2.8 0823 1250 7 14 24 36 45 40 24 18 3.2 0833 1850 10 17 32 49 50 45 32 21 5.2 900 0911 650 4 6 15 13 16 13 8 8 1.0 0921 1250 5 9 17 22 27 19 12 11 1.1 0931 1850 6 12 22 32 35 23 13 13 1.5 0912 650 5 9 16 23 30 27 18 16 2.8 0922 1250 7 14 25 38 44 39 27 21 3.2 0932 1850 10 18 34 47 50 45 33 26 5.2 7
-------------------------------------------------------------- TECHNICAL DATA, continued B-measurement Code Length Static set attenuation (db) as in ISO 7235:91 P-value (mm) (mm) 63 125 250 500 1K 2K 4K 8K 1000 1011 650 5 9 16 23 30 27 18 16 2.8 1021 1250 7 14 25 38 44 39 27 21 3.2 1031 1850 9 18 34 47 50 45 33 26 5.2 1041 2450 12 24 38 50 50 50 42 32 6.6 1012 650 4 6 10 12 16 12 9 8 0.9 1022 1250 5 9 16 20 24 17 12 11 0.9 1032 1850 6 11 21 28 30 20 13 12 1.1 1042 2450 7 14 26 36 37 23 15 13 1.2 1013 650 5 8 13 19 23 20 12 9 1.4 1023 1250 7 11 20 33 38 32 17 13 1.8 1033 1850 8 15 26 44 48 39 21 18 3.0 1043 2450 11 20 31 50 50 46 28 21 3.6 1100 1111 650 5 10 15 23 27 27 15 10 1.8 1121 1250 6 15 24 39 45 40 23 17 2.1 1131 1850 8 19 32 48 50 45 30 22 3.5 1141 2450 10 24 38 50 50 50 40 26 4.2 1112 650 5 9 16 23 30 27 18 16 4.0 1122 1250 7 14 25 38 44 40 27 21 5.0 1132 1850 10 19 34 47 50 45 33 26 8.0 1142 2450 12 24 38 50 50 50 42 32 10.0 1200 1211 650 4 7 10 14 17 13 8 8 1.1 1221 1250 5 10 17 24 28 20 12 10 1.2 1231 1850 6 11 22 33 38 25 14 11 1.6 1241 2450 6 13 27 42 48 31 17 11 1.9 1212 650 6 10 15 19 23 21 13 11 1.4 1222 1250 8 14 24 33 40 35 20 15 1.8 1232 1850 10 18 31 46 50 42 25 18 3.0 1242 2450 13 23 34 50 50 49 30 21 3.6 1213 650 6 11 16 24 30 28 17 13 4.0 1223 1250 9 16 25 39 46 40 27 20 5.0 1233 1850 11 19 32 48 50 45 34 26 8.0 1243 2450 14 28 36 50 50 50 44 31 10.0 1300 1321 1250 5 12 19 29 35 27 16 13 1.7 1331 1850 6 16 26 40 44 34 18 16 2.4 1341 2450 7 20 31 46 50 40 20 19 3.0 1322 1250 7 14 25 38 44 39 27 21 5.0 1332 1850 10 18 34 47 50 45 33 26 8.0 1342 2450 12 24 38 50 50 50 42 32 10.0 1400 1422 1250 5 11 18 27 32 22 13 12 1.4 1432 1850 6 14 25 38 42 27 15 15 1.9 1442 2450 8 17 29 49 50 33 18 17 2.3 1423 1250 7 12 21 33 39 33 18 14 1.9 1433 1850 8 15 28 44 48 40 23 18 3.2 1443 2450 11 21 33 50 50 47 30 22 3.9 1500 1521 1250 5 12 19 32 37 31 15 11 1.7 1531 1850 7 15 26 44 48 38 19 16 2.7 1541 2450 9 20 32 50 50 46 26 17 3.2 8
TECHNICAL DATA, continued B-measurement Code Length Static set attenuation (db) as in ISO 7235:91 P-value (mm) (mm) 63 125 250 500 1K 2K 4K 8K 1600 1621 1250 7 15 24 39 45 40 23 17 2.0 1631 1850 9 19 32 48 50 45 30 22 3.5 1641 2450 11 24 38 50 50 50 40 26 4.2 1622 1250 4 9 16 21 25 18 11 11 1.0 1632 1850 5 11 21 30 33 21 13 13 1.4 1642 2450 6 15 27 38 40 25 15 14 1.7 1800 1821 1250 6 13 20 31 37 31 16 14 1.7 1831 1850 8 17 28 42 45 38 21 17 2.7 1841 2450 10 21 33 47 50 46 25 20 3.2 1822 1250 5 9 15 26 31 25 8 6 1.3 1832 1850 6 11 20 40 44 33 10 9 1.7 1842 2450 7 16 25 49 51 43 17 10 2.0 2000 2022 1250 5 11 18 27 32 22 13 12 1.4 2032 1850 6 14 25 38 42 27 15 15 1.9 2042 2450 8 17 28 50 50 33 18 17 2.3 2023 1250 7 12 21 34 39 34 19 15 1.9 2033 1850 8 16 28 45 48 40 24 19 3.2 2043 2450 11 21 33 50 50 47 31 23 3.9 2200 2221 1250 7 14 22 35 40 36 20 15 1.9 2231 1850 9 18 30 46 47 43 26 19 3.2 2241 2450 10 24 35 50 50 50 33 23 3.9 2222 1250 4 9 17 22 27 19 12 11 1.1 2232 1850 6 12 22 32 35 23 13 13 1.5 2242 2450 7 15 28 39 43 28 15 14 1.8 9
-------------------------------------------------------------- MEASUREMENTS AND WEIGHTS B-measurement: 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1800, 2000, 2200 H-measurement: 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2200 B- and H-measurements in bold figures marked in yellow are standard: the others may be ordered. Total installation measurements in H plane: H+40 mm L = see the table in TECHNICAL DATA Weight = please contact your nearest Swegon office. SPECIFICATION Product Rectangular sound attenuator a aaaa bbbb x cccc x dddd Version: Code: Measurement: B x H x L Accessories T1 = Non-insulated inspection hatch T2 = Fire protected inspection hatch T3 = Attenuator supplied fire protected with 50 mm mineral wool. T4 = Perforated steel sheet cover N.B. If the attenuator is equipped with an inspection hatch there must be sufficient space to open the hatch. Fully opened, the hatch requires a distance of 700 mm. Figure 5. splitters are designed in accordance with the basic laws of aerodynamics. In addition, some of the active components of the attenuator are located outside the connection position. These improvements have considerably reduced the pressure drop in comparison with conventional attenuators. Order example Straight sound attenuator, code 0631, fulfilling the sound attenuation requirements as calculated. The attenuator is to be fitted with a non-insulated inspection hatch. The installation space is limited vertically to a maximum of 1300 mm, which means that there is sufficient room to open the inspection hatch (700 mm). Order code: a 0631 600x600x1850 T1 SPECIFICATION EXAMPLE Swegon rectangular sound attenuator, type, with the following functions: Aerodynamically formed splitters give extremely low pressure drop. Insulation material, approved by independent test institute: CLEANOLON -AL. Sound attenuation in db (stated clearly for different frequency bands) Pressure drop in Pa (stated clearly). Size a aaaa bbbb x cccc x dddd xx. units 10