Introduction to Johnson Controls Dampers

Transcription

1 Damper and Actuator Product Guide Damper Engineering Section Product Bulletin Issue Date 1297 Introduction to Johnson Controls Dampers For over 100 years, Johnson Controls has been the industry leader in automatic temperature control. We offer a complete line of Heating, Ventilating, and Air Conditioning (HVAC) controls, including top quality dampers for a wide range of applications, including: CD-1310 class III control damper CD-1320 class II control damper CD-1330 class I control damper BD-1300 balancing damper SD-1320 class II smoke damper SD-1330 class I smoke damper FD /2 hour fire-rated damper LD-1800 light duty damper RD-2000 round control damper To meet each customer s unique damper size and type requirements, we build dampers made-to-order. Dampers can be produced and shipped the next day after the order is received. Figure 1: Selection of Dampers Available Actuators and accessories are ordered with the damper, and can be factory installed or shipped separately, resulting in a damper which perfectly fits your application. All dampers and actuators have a three-year warranty on parts and workmanship Johnson Controls, Inc. 1 Code No. LIT , Rev. B

2 G eneral Dampers are an essential part of HVAC systems. They may control the pressure, temperature, or the amount of air entering, leaving, and flowing through a building. They may also be used to control the passage of smoke or restrict the passage of flame during fires. Johnson Controls dampers come in a variety of shapes and sizes to meet different application and environmental requirements. These include: volume (air) control applications, which regulate airflow temperature control applications, which regulate a constant temperature pressure control applications, which regulate a constant pressure smoke control to restrict the spread of smoke in HVAC systems that are designed to be automatically shut down in the event of a fire, or to control the movement of smoke within a building when the HVAC system is operational in engineered smoke control systems fire-rated, which interrupts airflow automatically through part of an air system so as to restrict the passage of flame, and installed in a fire-rated wall or floor to close automatically in the event of a fire to maintain the integrity of the fire-rated separation Each of these applications will be discussed later in this document in Damper Application Examples. The rectangular damper consists of five major components, identified in Figure 2 and described below: Frame--provides structural support Blades--provide the proper resistance to airflow Seals--prevent airflow when blades close Linkage--drives the blades to position Bearings--provide support and alignment for blade movement Frame Continuing the Johnson Controls effort to protect the environment, the frame is mechanically joined and uses no welding process. This manufacturing process improvement is standard for all of our damper product families. Rectangular Damper Construction Figure 3: 13-gauge Frame Assembly The frame shown in Figure 3 provides the structure and rigidity to the damper. A strong frame minimizes vibration and noise when the damper is exposed to high pressure and airflow. A rugged frame means less damage to the damper during shipping and installation. A square frame allows the blades to move freely, without twisting or binding. Figure 2: Rectangular Damper Components Individual panels can be quickly and easily coupled in the field to form multiple-section units with a modular frame. Blade stops provide sealing on top and bottom. 2 Introduction to Johnson Controls Dampers Product Bulletin

3 Blades Damper blades must withstand different levels of static pressure and velocities; some must provide low leakage rates, withstand high static pressures, or perform with minimal noise generation. The Johnson Controls family of dampers allows you to achieve these results by selecting 16-gauge, double-piece, or airfoil blades, as shown in Figures 4, 5, and 6. Seals Figure 4: 16-Gauge Blade Profile 16-gauge blades are made of 16-gauge rolled sheet metal. Figure 7: Replaceable Blade Seals Dampers with seals have lower leakage rates. This is important in applications where the flow of air must be fully shut off, such as outdoor air intakes and smoke dampers. Standard temperature seals are made of santoprene, which is a general purpose thermoplastic rubber. High-temperature seals are made of silicone. Figure 5: Double-Piece Blade Profile Double-piece blades are made from two layers of 22-gauge rolled sheet metal, mechanically joined. Figure 8: Frame Side Seal Rectangular dampers are provided with self- compensating stainless steel side seals, as shown in Figure 8. Figure 6: Airfoil Blade Profile Airfoil blades are made of extruded 1/16 inch thick aluminum. All dampers are available in 1 inch increments. Introduction to Johnson Controls Dampers Product Bulletin 3

4 Linkage The linkage connects the drive blade to the other blades, assuring simultaneous rotation of the blades. The linkage: features rugged, self-lubricating acetal (a polymer with up to 20% glass fiber) or bronze bearings for smooth, low-torque operation tested over 100,000 cycles is located in a side channel of the frame to reduce air noise, friction, and pressure drop requires no maintenance One blade in a multi-blade panel is always designated as the preferred drive blade and labeled accordingly, as shown in Figure 10. The actuator should be connected on the linkage side of this blade. This blade is recommended from experience to provide optimal performance and consistent mounting arrangements. For dampers with blades operating in parallel, any blade can be used as the drive blade. The ideal situation is to use a drive blade near the center of the damper height to distribute the torque evenly. For dampers with blades operating in opposed direction, the following blades should be used: Table 1: Single Drive Location Height, inches Blade 24 or less No. 1 or 3 Greater than 24 but less than 48 No. 3 or 5 Greater than 48 but 76 or less No. 5 or 7 For dampers using a single actuator, install the direct-mount actuator or associated actuator linkage to the linkage side of the recommended drive blade shown in Table 1. Use only odd-numbered blades for dampers with opposed blade rotation. Figure 9: Opposed and Parallel Operation The blades can operate parallel or opposed. In parallel operation, all the blades rotate in the same direction as shown in Figure 9 (right). In opposed operation, one blade rotates clockwise while the adjacent blade operates counterclockwise as shown in Figure 9 (left). The flow characteristics for the parallel and opposed operation differ significantly, but the pressure drop across the parallel and opposed dampers is identical. See Damper Application Examples for details. Table 2: Multiple Drive Location Height, inches Blade 30 Nos. 3 and 5 Greater than 30 but less than 48 Nos. 3 and 7 Greater than 48 but 76 or less Nos. 3 and 9 For dampers using multiple actuators, install the direct-mount actuator or associated actuator linkage to the linkage side of the recommended drive blades shown in Table 2. Note: Use only odd-numbered blades for dampers with opposed blade rotation. All other blades are connected to this blade by linkage. Additional linkage assemblies on multiple-section dampers should connect drive blade to drive blade for optimum performance. Figure 10: Drive Blade Identification 4 Introduction to Johnson Controls Dampers Product Bulletin

5 Bearings Johnson Controls offer two types of self-lubricating bearings: acetal and bronze. Selecting the proper bearing for your application is based on several factors: When cost is the only factor, acetal bearings would be the choice. In considering durability, bronze bearings are better where there are airborne contaminants that would attack the acetal bearing. For temperature limits, acetal bearings are rated to 250 F (121 C) and bronze bearings are rated to 350 F (177 C). Selecting the Correct Control Damper This section helps to determine appropriate applications for CD-1310, CD-1320, and CD-1330 Dampers. Dampers throttle or stop the flow of air through a duct or opening. The size and type of damper depends on the application and the environment. Listed below are some areas to consider when selecting a damper: What will be the maximum air velocity in the duct? What will be the maximum static pressure? What leakage rate will be acceptable? What will be the maximum and minimum operating temperature? Factors for selecting the appropriate model include the following: What is the control application (strategy)? Operating conditions including: - Velocity/pressure - Leakage - Temperature - Pressure drop - Closing Torque Figures 11 through 15 and Tables 3 through 5 provide the performance characteristics for the base models of control dampers. Table 3: Leakage Resistance Classes Class Static Pressure (inches water) I II III Leakage in cfm/sq ft Figure 11: CD-1310 Leakage Resistance Figure 12: CD-1320 Leakage Resistance Figure 13: CD-1330 Leakage Resistance Introduction to Johnson Controls Dampers Product Bulletin 5

6 Figures 11 through 13 show resultant air leakage through the damper, corrected to standard temperature and pressure conditions, as determined using instrumentation and procedures in accordance with AMCA Standard for Test Methods for Louvers, Dampers, and Shutters No It is not always an accurate characterization to have specifications list percent leakage. The truth is that the dynamics of airflow are not simple. The factors affecting leakage are static pressure, actuator torque (affecting how much the seals are compressed), and damper size. These variables interact with each other in an indirect manner. When it is stated that dampers have a leakage of 1/2%, you need to know how that percentage was derived. For example: A damper that is 24 x 24 inches may have a leakage rate of 12 cfm at a velocity of 600 fpm and 1 inch static pressure (this is equal to 1/2%). The same damper may have a leakage rate of 40 cfm under conditions such as 1000 fpm at 2 inches of static; in this case the damper has a leakage of 1%. That is why Johnson Controls rates our CD-1300 damper leakage in cfm at specific levels of velocity and static pressure. Table 4: Temperature Rating Description CD-1310 with standard seals and acetal bearings BD-1310 without seals and with bronze bearings CD-1320 with standard seals and acetal bearings CD-1320 with silicone seals and bronze bearings CD-1330 with standard seals and acetal bearings Closing Torque Table 5: Required Closing Torque Temp. Rating -40 to 200 F (-40 to 93 C) -65 to 350 F (-54 to 177 C) -40 to 200 F (-40 to 93 C) -65 to 350 F (-54 to 177 C) -40 to 200 F (-40 to 93 C) Operating Torque in lb/sq ft (in. static, fpm velocity) CD-1310 CD-1320 CD , , , Another important issue to consider is the amount of actuator closing torque available. To size an actuator, divide the rated torque from the actuator by the required closing torque of the damper for the given conditions from Table 5. Pressure Drop Figure 14: Recommended Pressure/Velocity Limits Figure 14 indicates the recommended velocity and pressure limits at various damper widths. Note: Figure 15: Pressure Drop The pressure drop is the same for all models due to identical frame construction. 6 Introduction to Johnson Controls Dampers Product Bulletin

7 Free Area Ratio Table 6 provides the free area ratio of Johnson Controls damper product families. Free area is the nominal area x free area ratio where nominal area = W x H of the damper frame. Table 6: Free Area Ratio Height Width, in. (cm) in. (cm) 8 (20) 12 (30) 16 (41) 20 (51) 24 (61) 28 (71) 32 (81) 36 (91) 40 (102) 44 (112) 48 (122) 6 (15) (36) (56) (76) (97) (107) (127) (148) (168) (188) (193) Coupled Panels Panels can be coupled to create larger damper banks. Such damper banks require special consideration: Are reinforcements needed? Some form of reinforcement, cross-bracing, or structural support should be installed for dampers subjected to high pressures or high air velocities. Refer to the CD-1300 Installation Instructions Control Dampers Only Installation Bulletin (LIT , Rev A). It is recommended that Support Bars (DMPR-KC200) be used for extra support at the intersection of four dampers. Are the damper sections correctly aligned? Each section must be vertically and horizontally aligned. If necessary, install shims to bring each section into alignment. For versatility and ease of ordering, multiple-section dampers are available for sizes up to 192 inches wide and 228 inches high. Multiple-section dampers are available in 1 inch increments only. Vertical coupling kits (DMPR-KC100) will be provided for sections greater than 76 inches high. All dampers are shipped as individual panels for field coupling. Figure 16: Multiple-Section Dampers Introduction to Johnson Controls Dampers Product Bulletin 7

8 Balancing Dampers BD-1300 Dampers come in a variety of sizes to meet different balancing application and environmental requirements. These include: volume (air) control applications, which regulate airflow pressure control applications, which maintain a constant pressure can be used in manual or motorized applications The BD-1300 Balancing Damper is the same frame and blade as a CD-1310 but has no seals and is not leakage rated. These dampers have no seals which requires less torque and therefore a smaller actuator may be used. Smoke Dampers A smoke damper is: intended to restrict the spread of smoke in HVAC systems that are designed to be automatically shut down in the event of a fire, or intended to control the movement of smoke within a building when the HVAC system is operational in engineered smoke control systems a 2-position control only SD-1320 Smoke Dampers meet UL Class II (leakage less than 20 cfm/sq ft at 4 inch W.C.) at 250 F (121 C) with acetal bearings, and 350 F (177 C) with bronze bearings. SD-1330 Smoke Dampers meet UL Class I (leakage less than 8 cfm/sq ft at 4 inch W.C.) at 250 F (121 C) with acetal bearings, and 350 F (177 C) with bronze bearings. Standard mechanically joined frames, double-piece and airfoil blades, are used in the construction of smoke dampers. This provides more cost-effective construction and keeps system performance characteristics the same as our control dampers. Smoke&Control Dampers Figure 17: Smoke Damper with Electric Actuator The SD-1320 and SD-1330 Smoke Dampers are designed to restrict the flow of smoke in the ductwork. These UL/cUL leakage rated dampers are listed under UL-555S Standard, dated May 1995, and are California State Fire Marshal listed. Electric and pneumatic actuators, UL tested and approved with the damper as a matched set, are factory assembled. Single-section dampers up to 48 inches wide x 76 inches high (122 x 193 cm) are approved for vertical or horizontal mounting. Figure 18: Smoke&Control Damper with Pneumatic Actuator The SD-1320 and SD-1330 Smoke&Control Dampers are designed to restrict the flow of smoke in the ductwork and operate as volume control dampers. These UL/cUL leakage rated dampers are listed under UL-555S Standard, dated May 1995, and are California State Fire Marshal listed. 8 Introduction to Johnson Controls Dampers Product Bulletin

9 SD-1300 Series Smoke&Control Dampers are also suitable for volume control. Pneumatic actuators, UL tested and approved for 100,000 cycles with the damper as a matched set, are factory assembled. Single-section dampers up to 48 inches wide x 76 inches high (122 x 193 cm) are approved for vertical or horizontal mounting. A Smoke&Control Damper is: intended to restrict the spread of smoke in HVAC systems that are designed to be automatically shut down in the event of a fire, or intended to control the movement of smoke within a building when the HVAC system is operational in engineered smoke control systems also suitable for proportional temperature and pressure control applications SD-1320 Smoke Dampers meet UL Class II (leakage less than 20 cfm/sq ft at 4 inch W.C.) at 250 F (121 C) with acetal bearings, and 350 F (177 C) with bronze bearings. SD-1330 Smoke Dampers meet UL Class I (leakage less than 8 cfm/sq ft at 4 inch W.C.) at 250 F (121 C) with acetal bearings, and 350 F (177 C) with bronze bearings. Standard mechanically joined frames, double-piece and airfoil blades, are used in the construction of Smoke&Control Dampers. This provides more cost-effective construction and keeps system performance characteristics the same as Johnson Controls control dampers. Fire Dampers Figure 19: Fire Damper Components A fire damper interrupts airflow automatically through part of an air system to restrict the passage of flame. Installed in a fire-rated wall or floor, the fire damper closes automatically in the event of a fire in order to maintain the integrity of the fire-rated separation. The FD /2 Hour Fire-rated Damper is designed to limit fire migration and maintain the integrity of the fire wall it is installed in, and to restrict airflow (oxygen) in the ductwork in fire situations. These dynamically tested fire-rated dampers are UL/cUL Listed under UL-555 Standard, dated May 1995, and are California State Fire Marshal listed. The spring on the FD-1300 provides the torque required to close and hold the damper blades against an airstream velocity of 3500 fpm at 8 inches W.C. static pressure in either direction of airflow. The damper is not designed to reopen except through manual intervention once the fusible link melts. If the temperature in the system climbs above 165 F (74 C), the fusible link will melt allowing the high-torque spring to close and lock the damper blades. 212 F (100 C) fusible link is optional. Single-section fire dampers are approved for the following: vertical mounting in walls made of masonry or gypsum wallboard with metal or wood studs up to 32 inches wide x 48 inches high (81 x 122 cm) horizontal mounting in cement floors up to 32 inches wide x 36 inches high (81 x 91 cm) Introduction to Johnson Controls Dampers Product Bulletin 9

10 Light Duty Dampers Table 7: LD-1800 Specifications Description 1 inch WG static pressure 4 inch WG static pressure Leakage (all sizes) 15 cfm 25 cfm Operational Torque 5 in lb 5 in lb Temperature Rating Approximate Weights (all sizes) -20 F to 200 F (-29 C to 93 C) 2.5 lb (1.13 kg) Table 8: LD-1800 Free Area Ratio Height, Width, inches inches Figure 20: LD-1800 Johnson Controls Light Duty Control Dampers are used in small ducts where maximum flow is required. Damper frames are constructed of formed, mechanically joined 18-gauge galvanized steel. Compressible spring stainless steel side seals are provided. Round Damper Construction Blade Shroud Damper blades are constructed with 16-gauge galvanized steel and have closed-cell polyurethane foam tape seals and a 5/16 inch round blade pin. Damper performance is designed for shutoff against a 6 inch pressure differential. Damper sealing force at 3 inches differential does not exceed 5 inch pounds per square foot. LD-1800 Dampers are ordered using the standard ordering system. LD-1800 Dampers are only available in 1 inch increments. Example: LOFNS-040 x 040 (4 inch W x 4 inch H) LOFNS-070 x 070 (7 inch W x 7 inch H) A 1/2 inch diameter shaft adapter is available. Seal Nylon Washer Shaft Figure 21: Round Damper Components The round damper consists of five major components: Shroud--provides structural support Blade--provides the proper resistance to airflow Shaft--drives the blade to position Washer--provides support for blade movement on diameters larger than 8 inches Seals--prevents airflow when blade is closed After rolling and forming, the shroud is mechanically joined for strength. 10 Introduction to Johnson Controls Dampers Product Bulletin

11 Damper Systems The manufacturer s published data is collected with the damper in a test environment, under controlled conditions. When dampers are affected by their surroundings, the published data will not always reflect the performance of the damper in an actual installation. The following factors affect the performance of dampers: Inlet and outlet conditions--certain conditions cause air currents which can adversely affect damper performance: - overhangs - projections - obstructions - adjacent walls - turbulence from a nearby discharge fan Damper location--the air entering the damper should be distributed evenly across the face of the damper, and the air leaving the damper should not be restricted. Take into consideration: - the nearness of duct elbows, both upstream and downstream from the damper - the location of the next damper Flow characteristics--the resistance offered by a parallel blade damper differs significantly from the resistance offered by an opposed blade damper. Damper authority--the impact of the damper on total system performance. See the Damper Engineering section of the Damper and Actuator Product Guide (FAN 268.1) for additional information. In-duct obstructions--some common in-duct obstructions include: - actuators - jackshaft assemblies - sensing devices - switching devices - structural supports - filters Installation quality--some common in-duct obstructions include: - squareness - proper installation per guidelines Damper Application Examples As stated earlier, dampers are used to control volume (air), pressure, or temperature. Volume Control Dampers Damper Regulates Air to Branch Figure 22: Volume Control Application A volume control damper regulates the flow of air, as shown in Figure 22. Common applications include: Isolating damper--this damper regulates the flow of air in branches of a duct system. This type of damper is either fully open or fully closed. The damper usually has seals to lower the leakage rate in the fully closed position. Modulation damper--unlike the isolating damper, the modulating damper must be able to hold the damper blades at a specified position to limit airflow. Fan inlet damper--either parallel or opposed blade dampers can be used to control the airflow rate to the fan--usually installed in an inlet box at the suction of the fan. Fan outlet damper--as with the fan inlet box damper, either parallel or opposed blade dampers can be used to provide proper control. Temperature Control Dampers Figure 23: Temperature Control Application Temperature control dampers operate as pairs, working together to maintain a predetermined temperature set point. The dampers simultaneously regulate two different airstreams, each having a different temperature. Introduction to Johnson Controls Dampers Product Bulletin 11

12 Temperature and Volume Control Dampers Figure 24: Pressure Control Application Control dampers can be used to control the temperature as well as maintain a constant volume of air. Figure 24 shows a typical mixed air control application. Dampers A and B work together to maintain a constant mixed-air temperature of air entering the coil. This is usually called the mixed air temperature. When these dampers are sized properly, they will also maintain a constant volume of air to the coil for all damper positions. Damper C will normally be controlled with Damper A with a common signal but in special cases, volume control can also be achieved by modulating Damper A with a control signal independent of Damper C. BD-1300: each panel is available in 1 inch increments from 8 to 48 inches in width and 6 to 76 inches in height. SD-1320: available in 1 inch increments from 10 to 48 inches in width and from 10 to 76 inches in height. SD-1330: available in 1 inch increments from 18 to 48 inches in width and from 10 to 70 inches in height. FD-1300: available in 1 inch increments from 10 to 32 inches in width and 10 to 48 inches in height for vertical mounting, and from 10 to 32 inches in width and 10 to 36 inches in height for horizontal mounting. LD-1800: available in 1 inch increments from 4 to 7 inches in width and 4 to 7 inches in height. RD-2000: available in 1 inch increments from 4 to 10 inches in diameter and 2 inch increments from 10 to 16 inches in diameter. Dimensional Information The damper is selected width x height, width dimension is listed first. All dimensions are from the outside of the frame. CD-1310: each panel is available in 1 inch increments from 8 to 48 inches in width and 6 to 76 inches in height. CD-1320: each panel is available in 1 inch increments from 8 to 48 inches in width and 6 to 76 inches in height. CD-1330: each panel is available in 1 inch increments from 8 to 48 inches in width and 7 to 76 inches in height. Note: Figure 25: Mounting Dimensions, inches Actual damper size will be less than width and height ordered. The performance specifications are nominal and conform to acceptable industry standards. For application at conditions beyond these specifications, consult the local Johnson Controls office. Johnson Controls, Inc. shall not be liable for damages resulting from misapplication or misuse of its products. Controls Group E. Michigan Street FAN P.O. Box 423 Damper and Actuator Product Guide Milwaukee, WI Printed in U.S.A. 12 Introduction to Johnson Controls Dampers Product Bulletin