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ASHRAE Indoor Air QualityGuidePresented For:Chicago ASHRAEBy:James Livingston, Regional Sales Manager,Ruskin Company1

Purpose of Presentation Comment on ASHRAE IAQGuide topics as related to aircontrol devices Provide information on thefunction and benefits of thesedevices Provide advice on theirapplication2

Presentation AgendaIAQ Guide BasicsObjectives1 Design & Construction2 Control Moisture4 Moisture in HVAC6 Capture/ExhaustContaminants7 Reduce Contaminants8 Advanced VentilationApproaches3

Purpose of IAQ Guide Provide advice on how provide good IAQvia means that are:– Cost effective– Practical– Currently available– Technologically sound– Sustainable– Goal: Increased usage & IAQ!4

Guide Approach 8 “Objectives” Objectives address components ofbuilding IAQ Each Objective contains individual“Strategies” to help achieve the Objective Benefits designers, constructors, ownersand facility managers5

Scope of IAQ Guide Buildings covered:– Commercial & institutional OfficeRetailEducationalLodgingPublic assembly6

Scope of IAQ Guide Buildings not covered:––––––––KitchensMedical procedure roomsNatatoriumsCold buildingsLaboratoryIndustrialResidentialChemical storage7

Why IAQ? Health & well being of occupants Financial success & sustainability ofbuilding8

Common Sources of Poor IAQ Two Basic Categories–Gaseous –Radon, C02, chemical vapors, etc.Biological (with 2 subcategories) Microbial– Bacteria, molds, mildews, viruses, dustmites, animal dander, etc.Particulate–Dust, pollen, building material fibers,process byproduct (such as saw dust), etc.“THE SOLUTION TOPOLLUTION IS DILUTION”W. K.

Health Issues Increased allergy & asthma symptomsColds & infectionsCarbon monoxide poisoningLegionnaires’ diseaseLung cancer from Radon exposure10

Financial Impact Repairs or modifications to correct issuesPotential temporary building closureDifficulty in renting spacesLegal action due to sick building or otherissues11

A Different Way Of Thinking Traditional high priority features includecost, space, aesthetics, etc. Make IAQ a priority in the beginning! Early discussions & strategies by all parties Improving IAQ after the fact is difficult andsometimes impossible12

Objective 1 Manage the Design &Construction Process to AchieveGood IAQ Strategy 1.1 Traditional Design13

Objective 1 Strategy 1.1 Integrated Design14

Objective 1 Strategy 1.2 Commissioning– Not just post-construction– Employ a Commissioning Authority (CxA) forpre-design and during construction– Ensure the design meets ownersrequirements and is being constructedcorrectly15

Objective 1 Strategy 1.3 Selecting HVAC Systems– Use environmentally-friendly & energy efficientsystems when possible– Displacement ventilation– If conventional means are used (CV, VAV, etc.),be sure good IAQ practices are used (62.1ventilation for example).16

Objective 1 Strategy 1.5 Effective Operation &Maintenance– O&M can be just as important as design &construction– Expected level of owner’s O&M efforts?– Consider O&M during design & construction– Provide documentation & training17

Objective 2 Control Moisture inBuilding Assemblies Moisture is a common cause of IAQ problems andresponsible for the most costly litigation andremediation Thermal bridging enables interior frost build-up &condensation Condensation liquid can travel through capillaryaction to inaccessible locations18

Objective 2 Strategy 2.2 Limit Condensation of WaterVapor within the Building Envelope and onInterior Surfaces– Use Thermally Efficient (Insulated) ControlDampers at outside air intakes19

Strategy 2.2 Why use Thermally EfficientDampers?– Reduce condensation toprevent bacteria, mold,mildew– Thermally broken to preventfrost build-up– Lessen leakage into or out ofspace Generally Class 1 leakage – 4cfm/ft² at 1” w.g.

AMCA 500-D Section 6.9 Thermal Efficiency Test Test setup Figure 5.10 Damper tested in bothairflow directions 2 F Steady StateTemperature for a period of10 minutes Applied torque

AMCA 500-D V-groove referencedamper 9 cfm per squarefoot at 1” w.c. How much moreefficient is the testdamper whencompared to thereference damper?

Thermally Efficient Damper Features Insulated & thermallybroken blades Blade & jamb seals forlow leakage Thermally brokenframes Non-metallic bearings

Thermally Efficient Damper Performance AMCA Standard 500-D– AMCA certified leakage– AMCA certified performance– AMCA certified Thermal Efficiency

Objective 2 Strategy 2.3 Maintain Proper BuildingPressurization– Building pressure affects moisture infiltrationand exfiltration– Negative pressure in hot, humid conditionspromotes moisture infiltration into spaces– Positive pressure in humid spaces increasescondensation buildup within envelope25

Strategy 2.3 Pressurization often is not consistentthroughout building due to:– Stack effect– Wind speed & direction– Temperature– HVAC supply & exhaust rates26

Strategy 2.3 Airflow measuring stations can assist withpressurization27

Pick the Product for the Application Use Electronic Air Flow Measurement forvery low velocities and large openings Use Velocity Pressure Measurement for highvelocities or small openings.

Electronic Airflow Measuring Thermistors, heated mass flow sensors,hot film anemometers, etc.– Measures energy to heat element– Low velocities – as little as 0 fpm29

Velocity Pressure Airflow Measuring Differential Pressure– Minimum 300 fpmTotal Pressure ChamberPtPsStatic Pressure ChamberPv Pt - Ps

Locations For Airflow Measuring Stations

Suggestions for Measuring OutsideAirVAV & CV Systems Air measuringstation w/ controldamper built-in Damper control ismanual or by BASDCV Systems Air measuringstation with built-incontrol damper andcontrol system Control systemmaintains CFM setpoint as fans scrollup and downAny system, limitedspace Air measuringcombined withoutside air louver Can be as little as4” total depth32

Suggestions for Measuring SupplyAirFan inlet Highest velocitypoint in the system Total system supplyairflowRetrofit – single flooror pressure area Probes or stations Can install as closeas 4” in front ofexisting dampersNew construction –single floor or pressurearea Air measuringstation w/ controldamper built-in Damper control ismanual or by BAS33

Suggestions for Measuring ReturnAirRetrofit – single flooror pressure area Probes or stations Can install as closeas 4” in front ofexisting dampersNew construction –single floor or pressurearea Air measuringstation w/ controldamper built-in Damper control ismanual or by BAS34

Suggestions for Measuring ExhaustAirUse velocity pressure probesor stations Works well with highvelocity exhaust airflow Much less expensive thanelectronic airflow stations35

Objective 4 Control Moisture &Contaminants Related toMechanical Systems Strategy 4.1 Control Moisture and Dirt in AirHandling Systems– Fungi & bacteria are normally present on buildinginterior surfaces, including HVAC components– Microorganism growth in HVAC system results inmalodors, nasal & throat irritation and buildingrelated illnesses36

Strategy 4.1 Outside air louvers can prevent rainpenetrationLouvers37

Louvers With Plenum Behind38

Water Penetration39

Sloped Plenum Detail40

Strategy 4.1 Traditional louvers provide protectionfrom non-storm rain Wind Driven Rain Resistant louver providestorm condition protection Let’s look at the differences 41

Strategy 4.1 Traditional Louvers:– Horizontal blades– Drain Gutters– Wide Spacing– High Free Area– Low Cost– Stops some rain– Not effective in storms42

Strategy 4.1 Traditional louver sizing– AMCA Water Penetration test – BeginningPoint of Water Penetration free area velocity(FAV)– Determine design FAV considering AMCA testdata– CFM/FAV Total Free Area required– Reference louver Free Area Guide todetermine appropriate louver size43

Standard 500-L Louvers5.6 Water PenetrationAir ExhaustWaterdrop ManifoldWetted Wall ManifoldWaterDropletsTest UnitAir Entrainedinto chamberthrough louverExhaustFanAir FlowMeasurementCollectionZone“Still Air”Condition!

Standard 500-L LouversTest Conditions 48” x 48” size 15 minute intervals Manifold (raindrops) - 4” perhour (3.15 gal/15 min) Wetted wall - .25 gpm (3.75gallons/15 min) Ventilation airflow only – nowind 1250 fpm max free areavelocity

AMCA “Still Air” Water Test

Water Penetration GraphBeginning PointOf WaterPenetration: .01oz/ft² at 1,023fpm Free AreaVelocity.01 oz./ft²of freearea

“Still Air” Test with Non-drainable Louver

Traditional Louvers Where to use:– Properly drained applications Sloped plenums & ductwork Floor drains– Protected areas (overhangs, barriers, interior,non-prevailing wind elevations)– “Screen” applications (vision barriers) Sizing– Use Safety Factor (15% to 20% min) Does NOT stop storm rain

Traditional Drainable Louver29 mph wind, 3”/hr rain, 1,000 fpm intake velocity

New Louver Technology Wind Driven Rain Louvers– Horizontal or Vertical blades– Drain Gutters on horizontal– Hooks on vertical– Close spacing– Lower Free Area– Higher Velocity– Effective in storms51

Std 500-L Wind Driven Rain Test5.11 Water Rejection Wind Driven RainAir ExhaustTest LouverRain WaterDischargeNozzlesWind/RainMachineWind DrivenRain plusAir EntrainedInto ChamberThrough LouverExhaust FanCollection Zone52

Std 500-L Wind Driven RainTest Rejection Effectiveness ClassesA 99% to 100%B 95% to 98.9%C 94.9% to 80%D below 80% (std. louvers)3” rain/29 mph wind8” rain/50 mph wind53

Wind Driven Rain Louver29 mph wind, 3”/hr rain, 2,000 fpm intake velocity

Rear view, 29 mph wind, 3”/hr rain, 2,000 fpm intake velocity

How Much Water Is Applied? 3” Per Hour Rain On 1m X 1m 21 Gallons Applied Over 1 Hr.– Class A (99% or better) allows 27 fl. oz penetration– Class D (80% or worse) allows over 4 gallons– Std Louvers (60% or lower) - over 7 gallons

Wind Driven Rain Louver Benefits Prevent rain infiltration– Lessens interior water damage & mold growth– Helps keep walls & floors dry– Helps keep filters dry– Excellent for Penthouses Allow higher intake velocities– Use smaller louvers! Reduce future problems & liability

Wind Driven Rain LouversHorizontal blade models40% - 50%free area2” to 8” deepClass A @800 to 1200fpmModerate pTraditionalappearanceVertical blade models40% - 45%free area3” to 7” deepClass A @1500 to 2100fpmLow pBestperformance58

Sizing Example 48” x 48” & 7,000 cfm 6” Traditional710 fpm.07” p60% Wind DrivenRain Effectiveness(29 mph)Cost 1.0 5” Horizontal WDR1,002 fpm.16” p99.8% Wind DrivenRain Effectiveness(29 mph)Cost 1.7 6” Vertical WDR1,030 fpm.09” p99.8% Wind DrivenRain Effectiveness (50mph)Cost 2.748” x 36” (25% smaller)1,488 fpm.18” p99.8% Wind Driven RainEffectiveness (50 mph)Cost 2.3

Rooftop IntakesTraditional style, allowsrain penetrationWind Driven Rain Design,prevents rain penetration

What About Snow?61

Suggestion for Stopping SnowPenetration Heated screen behind louver Prevents snow blowing intoductwork Reasonable pressure drop Relatively slow airflow - 350 FPMFace area velocity.

Objective 7 Reduce ContaminantConcentrations through Ventilation,Filtration and Air Cleaning First goal is to reducing contaminant sources,then capturing & exhausting Remaining contaminants should be– Diluted with ventilation air, or– Reduced by filtration and gas-phased air cleaning(FAC)63

Strategy 7.2 Continuously Monitorand Control Outdoor Air Delivery Fixed minimum outdoor air dampers may notprovide optimum control of intake CFM,particularly in VAV systems Over-ventilation is common now – estimated30% annual savings in U.S. building energy costsif ventilation per standards is maintained64

Suggestion for Maintaining ProperOutdoor Air Intake Levels Use air measuring station with built-in controldamper and control system to maintain CFM setpoint65