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Control Dampers
This document discusses control dampers and their integration into building management systems for energy conservation. It covers damper basics, leakage, design for energy efficiency, and fire/smoke damper actuators. Control dampers regulate air flow through ducts and openings. Properly specifying low leakage dampers and modulating actuators can improve energy efficiency. International building codes require low leakage dampers and economizers.
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Control Dampers
- 1. Air Control Considerations For Energy Conservation & BMS Integration Presenter: James Livingston, Ruskin Company
- 2. We Will Discuss Control Damper Basics Control Damper Leakage Control Damper Design For Energy Conservation Fire/Smoke Damper Acutators For Energy Conservation
- 3. What is aControl Damper? One or more movable blades Mounts in ducts or openings Regulates the flow of air
- 4. Control Damper Applications Air Handling Units (AHU) Mixing Boxes Fresh Air (FA) Return Air (RA) Backdraft Dampers (BD) Zone Mixing Dampers (ZMD)
- 5. Parts of aControl Damper Frame Linkage Blade Jamb Seals Blade Seals
- 6. Damper Construction Galvanized Aluminum Frames V-Groove Blades Airfoil Blades
- 7. V-Groove Blade Dampers •Velocities less than 1500 FPM • 3”- 4” Static Pressure • Noise not a factor
- 8. Airfoil Blade Dampers • Velocities above 2000 FPM • Above 3”- 4” Static Pressure • Noise is a concern • Lowest Pressure Drop Required
- 9. How Are Fire,Fire/Smoke and Smoke Dampers Different? Maintains fire or smoke walls Fire dampers - steel construction Often have sleeves Usually not controlling air That is changing!
- 10. Damper Leakage –What is it? Per AMCA Publication 502, Damper Application Manual for Heating, Ventilating and Air Conditioning: “The Air Leakage, or Sealing Performance, of a closed damper is the airflow leakage rate through the damper for a given pressure differential across the damper.”
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- 12. Why Are WeConcerned? Code requirements Energy losses due to escaping conditioned air through closed damper Maintaining pressure in system with closed damper
- 13. Control Damper LeakageClasses
- 14. Smoke & Fire/SmokeDamper Leakage Classes
- 15. Damper Leakage Notes Leakage is a function of Pressure, not Airflow Generally expressed or plotted as: Cfm/ft² of damper face area at a certain pressure and with a certain seating torque Metric: m³/second per m² Example for a 24” x 24” opposed blade damper: 32 cfm/ft² @ 4” w.g. pressure with 5 inch- pounds/ft² torque applied holding damper closed
- 16. Calculating Leakage Mostdampers have published leakage at 1” w.g. Multiply the cfm leakage at 1” times the square root of the desired pressure Example 10 cfm @ 1” w.g. = 20 cfm @ 4” w.g. Be sure the damper is rated for the higher pressure!
- 17. International Codes International codeshave been adopted in All 50 states, D.C. & Puerto Rico One or more International Codes currently enforced statewide www.iccsafe.org 17
- 18. International Codes International codesmandate… Occupancy-based ventilation (IMC 403.3) VAV systems shall have controls to monitor and maintain O.A. flow based on 403 requirements, through the entire range of the system (IMC403.3.3) All dampers penetrating the building envelope shall be class 1 leakage rated, not to exceed 4cfm/sf @ 1” w.c. (IMC301.2, IBC1301 & IECC) Motorized dampers required on building envelope penetrations (IECC 502.4.4 & 503.2.4.4) D.O.E. mandates ASHRAE 90.1 as a minimum for all Federal buildings. (IECC 4 CFM Supersedes)
- 19. International Codes “The occupant load utilized for design of the ventilation system shall not be less than the number determined from the estimated maximum occupant load rate indicated in Table 403.3”
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- 21. International Mechanical Code ergy g En rdin tion ega rva R C onse
- 22. International Building Code rgy Ene ding ion R egar rvat Co nse
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- 24. International Energy ConservationCode • Required in all states that have adopted the IBC or IMC. • Addresses OA & EA Damper leakage 4 cfm/ft2 @ 1” w.g. • Economizers Required (503.3.1 & 503.4.1) • Refers to 90.1 for climate zones and as a standard for applications not covered in the code.
- 25. ASHRAE 90.1 6.4.3.3.3 Motorized dampers required on OA & EA applications 6.5.1.1 Economizers required
- 26. Specifying Low Leakage Dampers AMCA 511 Certification Independent testing Verified catalogs Periodic Check Tests
- 27. AMCA International Certified RatingsProgram… How do you know the product you specified is licensed by AMCA International? There are basically four ways to determine if a product is participating in AMCA International’s Certified Ratings Program. They are: WWW.AMCA.org Manufacture Model # Manufacture’s Catalog (most are online) Certified Ratings Seal on the product (could be too late) Contact AMCA International Phone 847-394-0150 Fax 847-253-0088 Email crp@amca.org 27
- 28. AMCA 511 DamperAir Leakage At least two sizes tested 12” x 48” Max width x 36” Up to two more sizes can be tested, 36” max tall AMCA configs 5.4, 5.5 or 5.6 Round dampers Min & Max sizes tested
- 29. AMCA 511 DamperAir Leakage AMCA 500 Test Standard Figure 5.5 Leakage & Pressure
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- 32. Air Leakage Certification Not the same! Be sure it’s rated for Air Leakage, not just Air Performance!
- 33. Energy Saving Damper Construction Blades Jamb Seals Blade Seals
- 34. Blades Galvanized Aluminum V-Groove Blades Generally not Class 1 Airfoil Blades Class 1 and 1A available
- 35. Airfoil Blades Advantages Best Torsion Performance No Twist Best Closure Seal For All Blade Lengths Class 1 & 1A available
- 36. Airfoil vs. “V”Groove Maximums Blade Shape Matters Airfoil 60” Span @ 3.5 w.g. 3000 FPM 3-VEE 48’ Span @ 2.5 w.g. 1500 FPM
- 37. Airfoil vs. “V”Groove Pressure Drop Airfoil 24” x 24” .07 w.g. @ 2000 FPM 3-VEE .19 w.g. @ 2000 FPM Almost 3 times the Pressure Drop!
- 38. Jamb Seals Betweenends of blades and jamb frames Metallic or synthetic material Compresses when blades close
- 39. Blade Seals BladeSeals Mechanically Locked Inflatable Maintenance Wiper Type No Adhesive or Clip On Style
- 40. Insulated Dampers Reducesthermal energy loss Different methods Double airfoil damper - expensive Single airfoil foam injected blades – less expensive Thermal break frames available Class 1 leakage Applications down to -100°F
- 41. Combination Louvers Drainable fixed louver & airfoil control damper in same frame Class 1 leakage Meets IECC building envelope leakage requirement! Available w/ most electric actuators Louver & Damper Less product cost than separate in One! louver, damper & sleeve Less installation cost 41
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- 43. Electric Actuator Types Actuators are available in three types: 1) Two Position Spring Return 2) Modulating 3) Power Open-Power Closed Can be controlled by BMS Most Damper applications call for Two Position Spring Return or Modulating
- 44. Two Position Limit tolimit operation – does not float Open/close applications Spring reverses direction when power fails Typically 120V or 24V voltage Power draw for common 175 in/lb model 120V – 60 VA driving, 13 VA holding 24V – 40 VA driving, 8 VA holding
- 45. Modulating Actuator moves tooany point within its rotation limits to control airflow Requires a control signal 2-10 Vdc or 4-20 mA Signal can come from BMS based on: Temperature Pressure Air pollutants and/or occupancy Power draw for common 175 in/lb model 24V – 16 VA driving, 5 VA holding
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- 47. Modulating Considerations Airflownot linear to blade position
- 48. Modulating Considerations Linear flow damper characteristics From AMCA Pub 502 Damper Application Manual
- 49. Modulating Fire/Smoke andSmoke Damper Actuators BMS signal controls blade position in normal condition Damper closes fully during fire Damper opens fully to relieve smoke
- 50. Modulating Smoke &F/S Dampers
- 51. Modulating Smoke &F/S Dampers Eliminates balancing dampers Less pressure drop Less cost Use smoke dampers for return air on Air Handlers Maintain floor pressure in multi floor systems
- 52. Modulating Smoke &F/S Dampers Advantage over manual balancing dampers Modulating actuator goes full-open for smoke purge Smoke system does not have to fight semi- closed manual dampers
- 53. 3-Position Smoke &F/S Dampers No Control Signal Required Built in potentiometer to 20% to 100% balance position Allows the damper to be SET at any position for BALANCING AIRFLOW under normal operations, open or closed for SMOKE CONTROL and closed as required in the fire area
- 54. Summary Current buildingcodes require low leakage dampers Damper construction greatly affects leakage characteristics Modulating actuators can be controlled by BMS to adjust airflow for temperature and IAQ requirements Smoke and Fire/Smoke dampers are available w/ modulating & 3-position actuators
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