Air Control Considerations For Energy Conservation & BMS IntegrationPresenter: James Livingston,Ruskin Company
We Will Discuss Control Damper Basics Control Damper Leakage Control Damper Design For Energy Conservation Fire/Smoke Damper Acutators For Energy Conservation
What is a Control Damper?One or more movable bladesMounts in ducts or openingsRegulates the flow of air
Control Damper Applications Air Handling Units (AHU) Mixing Boxes Fresh Air (FA) Return Air (RA) Backdraft Dampers (BD) Zone Mixing Dampers (ZMD)
Parts of a Control Damper Frame Linkage Blade Jamb Seals Blade Seals
Damper Construction Galvanized Aluminum FramesV-Groove Blades Airfoil Blades
V-Groove Blade Dampers• Velocities less than 1500 FPM• 3”- 4” Static Pressure• Noise not a factor
Airfoil Blade Dampers• Velocities above 2000 FPM• Above 3”- 4” Static Pressure• Noise is a concern• Lowest Pressure Drop Required
How Are Fire, Fire/Smoke andSmoke Dampers Different? Maintains fire or smoke walls Fire dampers - steel construction Often have sleeves Usually not controlling air That is changing!
Damper Leakage – What is it?Per AMCA Publication 502, DamperApplication Manual for Heating,Ventilating and Air Conditioning:“The Air Leakage, or SealingPerformance, of a closed damper isthe airflow leakage rate through thedamper for a given pressuredifferential across the damper.”
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
Calculating Leakage Most dampers 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!
International CodesInternational codes have been adopted inAll 50 states, D.C. & Puerto Rico One or more International Codes currently enforced statewide www.iccsafe.org 17
International CodesInternational codes mandate… 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)
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”
International Energy Conservation Code • 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.
ASHRAE 90.1 220.127.116.11.3 Motorized dampers required on OA & EA applications 18.104.22.168 Economizers required
AMCA InternationalCertified Ratings Program… 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 firstname.lastname@example.org 27
AMCA 511 Damper Air 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
AMCA 511 Damper Air Leakage AMCA 500 Test StandardFigure 5.5 Leakage & Pressure
Airfoil vs. “V” Groove Pressure DropAirfoil 24” x 24” .07 w.g. @ 2000 FPM3-VEE .19 w.g. @ 2000 FPMAlmost 3 times the Pressure Drop!
Jamb Seals Between ends of blades and jamb frames Metallic or synthetic material Compresses when blades close
Blade Seals Blade Seals Mechanically Locked Inflatable Maintenance Wiper Type No Adhesive or Clip On Style
Insulated Dampers Reduces thermal 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
Combination Louvers Drainable fixed louver & airfoil control damper in same frame Class 1 leakage Meets IECC building envelope leakage requirement! Available w/ most electric actuatorsLouver & Damper Less product cost than separatein One! louver, damper & sleeve Less installation cost 41
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
Two PositionLimit to limit operation – does notfloatOpen/close applicationsSpring reverses direction whenpower failsTypically 120V or 24V voltagePower draw for common 175 in/lbmodel 120V – 60 VA driving, 13 VA holding 24V – 40 VA driving, 8 VA holding
ModulatingActuator moves too any point withinits rotation limits to control airflowRequires a control signal 2-10 Vdc or 4-20 mASignal can come from BMS based on: Temperature Pressure Air pollutants and/or occupancyPower draw for common 175 in/lbmodel 24V – 16 VA driving, 5 VA holding
Modulating Smoke & F/S DampersEliminates balancingdampers Less pressure drop Less costUse smoke dampers forreturn air on Air HandlersMaintain floor pressure inmulti floor systems
Modulating Smoke & F/S DampersAdvantage overmanual balancingdampers Modulating actuator goes full-open for smoke purge Smoke system does not have to fight semi- closed manual dampers
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
Summary Current building codes 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