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ASHRAE Indoor Air Quality Guide
Presented For:
Chicago ASHRAE
By:
James Livingston, Regional Sales Manager,
Ruskin Company
1
Purpose of Presentation• Comment on ASHRAE IAQ
Guide topics as related to air
control devices
• Provide information on the
function and benefits of these
devices
• Provide advice on their
application
2
Presentation Agenda
3
IAQ Guide Basics
Objectives
1 Design & Construction
2 Control Moisture
4 Moisture in HVAC
6 Capture/Exhaust Contaminants
7 Reduce Contaminants
8 Advanced Ventilation Approaches
Purpose of IAQ Guide• Provide advice on how provide good IAQ
via means that are:
– Cost effective
– Practical
– Currently available
– Technologically sound
– Sustainable
– Goal: Increased usage & IAQ!
4
Guide Approach• 8 “Objectives”
• Objectives address components of
building IAQ
• Each Objective contains individual
“Strategies” to help achieve the Objective
• Benefits designers, constructors, owners
and facility managers
5
Scope of IAQ Guide• Buildings covered:
– Commercial & institutional
• Office
• Retail
• Educational
• Lodging
• Public assembly
6
Scope of IAQ Guide• Buildings not covered:
– Kitchens
– Medical procedure rooms
– Natatoriums
– Cold buildings
– Laboratory
– Industrial
– Residential
– Chemical storage
7
Why IAQ?• Health & well being of occupants
• Financial success & sustainability of
building
8
Common Sources of Poor IAQCommon Sources of Poor IAQ
• Two Basic Categories– Gaseous
• Radon, C02, chemical vapors, etc.
– Biological (with 2 subcategories)
• Microbial– Bacteria, molds, mildews, viruses, dust
mites, animal dander, etc.
• Particulate – Dust, pollen, building material fibers,
process byproduct (such as saw dust), etc.
“THE SOLUTION TO “THE SOLUTION TO “THE SOLUTION TO “THE SOLUTION TO
POLLUTION IS DILUTION”POLLUTION IS DILUTION”POLLUTION IS DILUTION”POLLUTION IS DILUTION”W. K.W. K.W. K.W. K.
Health Issues• Increased allergy & asthma symptoms
• Colds & infections
• Carbon monoxide poisoning
• Legionnaires’ disease
• Lung cancer from Radon exposure
10
Financial Impact
• Repairs or modifications to correct issues
• Potential temporary building closure
• Difficulty in renting spaces
• Legal action due to sick building or other
issues
11
A Different Way Of Thinking• Traditional high priority features include
cost, space, aesthetics, etc.
• Make IAQ a priority in the beginning!
• Early discussions & strategies by all parties
• Improving IAQ after the fact is difficult and
sometimes impossible
12
Objective 1 Manage the Design &
Construction Process to Achieve
Good IAQ• Strategy 1.1 Traditional Design
13
Objective 1
• Strategy 1.1 Integrated Design
14
Objective 1
• Strategy 1.2 Commissioning
– Not just post-construction
– Employ a Commissioning Authority (CxA) for
pre-design and during construction
– Ensure the design meets owners
requirements and is being constructed
correctly
15
Objective 1
• Strategy 1.3 Selecting HVAC Systems
– Use environmentally-friendly & energy efficient
systems when possible
– Displacement ventilation
– If conventional means are used (CV, VAV, etc.),
be sure good IAQ practices are used (62.1
ventilation 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 & training
17
Objective 2 Control Moisture in
Building Assemblies• Moisture is a common cause of IAQ problems and
responsible for the most costly litigation and
remediation
• Thermal bridging enables interior frost build-up &
condensation
• Condensation liquid can travel through capillary
action to inaccessible locations
18
Objective 2• Strategy 2.2 Limit Condensation of Water
Vapor within the Building Envelope and on
Interior Surfaces
– Use Thermally Efficient (Insulated) Control
Dampers at outside air intakes
19
Strategy 2.2
• Why use Thermally Efficient
Dampers?
– Reduce condensation to
prevent bacteria, mold,
mildew
– Thermally broken to prevent
frost build-up
– Lessen leakage into or out of
space
• Generally Class 1 leakage – 4
cfm/ft² at 1” w.g.
AMCA 500-D Section 6.9
• Thermal Efficiency Test
• Test setup Figure 5.10
• Damper tested in both
airflow directions
• ±2°F Steady State
Temperature for a period of
10 minutes
• Applied torque
AMCA 500-D
• V-groove reference damper
• 9 cfm per square foot at 1” w.c.
• How much more efficient is the test damper when compared to the reference damper?
• Insulated & thermally
broken blades
• Blade & jamb seals for
low leakage
• Thermally broken
frames
• Non-metallic bearings
Thermally Efficient Damper Features
• AMCA Standard 500-D– AMCA certified leakage
– AMCA certified performance
– AMCA certified Thermal Efficiency
Thermally Efficient Damper Performance
Objective 2• Strategy 2.3 Maintain Proper Building
Pressurization
– Building pressure affects moisture infiltration
and exfiltration
– Negative pressure in hot, humid conditions
promotes moisture infiltration into spaces
– Positive pressure in humid spaces increases
condensation buildup within envelope
25
Strategy 2.3
• Pressurization often is not consistent
throughout building due to:
– Stack effect
– Wind speed & direction
– Temperature
– HVAC supply & exhaust rates
26
Strategy 2.3• Airflow measuring stations can assist with
pressurization
27
Pick the Product for the Application
• Use Electronic Air Flow Measurement for
very low velocities and large openings
• Use Velocity Pressure Measurement for high
velocities 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 fpm
29
Pv = Pt - Ps
PsPt
Total Pressure Chamber
Static Pressure Chamber
Velocity Pressure Airflow Measuring
• Differential Pressure
– Minimum 300 fpm
Locations For Airflow Measuring Stations
Suggestions for Measuring Outside
Air
32
VAV & CV Systems
• Air measuring
station w/ control
damper built-in
• Damper control is
manual or by BAS
DCV Systems
• Air measuring
station with built-in
control damper and
control system
• Control system
maintains CFM set
point as fans scroll
up and down
Any system, limited
space
• Air measuring
combined with
outside air louver
• Can be as little as
4” total depth
Suggestions for Measuring Supply
Air
33
Fan inlet
• Highest velocity
point in the system
• Total system supply
airflow
Retrofit – single floor
or pressure area
• Probes or stations
• Can install as close
as 4” in front of
existing dampers
New construction –
single floor or pressure
area
• Air measuring
station w/ control
damper built-in
• Damper control is
manual or by BAS
Suggestions for Measuring Return
Air
34
Retrofit – single floor
or pressure area
• Probes or stations
• Can install as close
as 4” in front of
existing dampers
New construction –
single floor or pressure
area
• Air measuring
station w/ control
damper built-in
• Damper control is
manual or by BAS
Suggestions for Measuring Exhaust
Air
35
Use velocity pressure probes
or stations
• Works well with high
velocity exhaust airflow
• Much less expensive than
electronic airflow stations
Objective 4 Control Moisture &
Contaminants Related to
Mechanical Systems• Strategy 4.1 Control Moisture and Dirt in Air-
Handling Systems
– Fungi & bacteria are normally present on building
interior surfaces, including HVAC components
– Microorganism growth in HVAC system results in
malodors, nasal & throat irritation and building-
related illnesses
36
Strategy 4.1
• Outside air louvers can prevent rain
penetration
37
Louvers
Louvers With Plenum Behind
38
Water Penetration
39
Sloped Plenum Detail
40
Strategy 4.1• Traditional louvers provide protection
from non-storm rain
• Wind Driven Rain Resistant louver provide
storm 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 storms
42
Strategy 4.1• Traditional louver sizing
– AMCA Water Penetration test – Beginning
Point of Water Penetration free area velocity
(FAV)
– Determine design FAV considering AMCA test
data
– CFM/FAV = Total Free Area required
– Reference louver Free Area Guide to
determine appropriate louver size
43
Air ExhaustWater
Droplets
Waterdrop Manifold
Wetted Wall Manifold
Test Unit
Air Entrained into chamber
through louver
Air FlowMeasurement
CollectionZone
ExhaustFan
“Still Air” Condition!
Standard 500-L Louvers5.6 Water Penetration
Test Conditions
• 48” x 48” size
• 15 minute intervals
• Manifold (raindrops) - 4” per hour (3.15 gal/15 min)
• Wetted wall - .25 gpm (3.75 gallons/15 min)
• Ventilation airflow only – no wind
• 1250 fpm max free area velocity
Standard 500-L Louvers
AMCA “Still Air” Water Test
Water Penetration GraphBeginning Point Of Water Penetration: .01 oz/ft² at 1,023 fpm Free Area Velocity
.01 oz./ft² of free area
“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 Louver
29 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 storms
51
52
Wind/RainMachine
Test Louver
Wind DrivenRain plus
Air EntrainedInto Chamber
Through Louver
Air Exhaust
Exhaust FanCollection Zone
Rain WaterDischargeNozzles
Std 500-L Wind Driven Rain Test
5.11 Water Rejection Wind Driven Rain
• Rejection Effectiveness Classes
A 99% to 100%
B 95% to 98.9%
C 94.9% to 80%
D below 80% (std. louvers)
• 3” rain/29 mph wind
• 8” rain/50 mph wind
53
Std 500-L Wind Driven Rain Test
Wind Driven Rain Louver
29 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 models Vertical blade models
58
40% - 50% free area
2” to 8” deep
Class A @ 800 to 1200 fpm
Moderate ∆p
Traditional appearance
40% - 45% free area
3” to 7” deep
Class A @ 1500 to 2100 fpm
Low ∆p
Best performance
Sizing Example• 48” x 48” & 7,000 cfm
• 6” Traditional• 710 fpm• .07” ∆p• 60% Wind Driven Rain Effectiveness (29 mph)
• Cost 1.0
• 5” Horizontal WDR• 1,002 fpm• .16” ∆p• 99.8% Wind Driven Rain Effectiveness (29 mph)
• Cost 1.7
• 6” Vertical WDR• 1,030 fpm• .09” ∆p• 99.8% Wind Driven Rain Effectiveness (50 mph)
• Cost 2.7
• 48” x 36” (25% smaller)• 1,488 fpm• .18” ∆p• 99.8% Wind Driven Rain Effectiveness (50 mph)
• Cost 2.3
Rooftop Intakes
Traditional style, allows rain penetration
Wind Driven Rain Design, prevents rain penetration
What About Snow?
61
Suggestion for Stopping Snow Penetration
• Heated screen behind louver
• Prevents snow blowing into
ductwork
• Reasonable pressure drop
• Relatively slow airflow - 350 FPM
Face area velocity.
Objective 7 Reduce Contaminant
Concentrations 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 Monitor
and Control Outdoor Air Delivery
• Fixed minimum outdoor air dampers may not
provide optimum control of intake CFM,
particularly in VAV systems
• Over-ventilation is common now – estimated
30% annual savings in U.S. building energy costs
if ventilation per standards is maintained
64
Suggestion for Maintaining Proper
Outdoor Air Intake Levels
• Use air measuring station with built-in control
damper and control system to maintain CFM set
point
65
Air Measuring & Control Stations
• Advantages
– System automatically modulates
damper to maintain CFM
– Can be used as minimum outside air
damper only (overridden when
economizer damper opens), or
– Can be used as entire outside air
damper
66
� Air Measuring & Control Damper
Documentation I/O Chart
� Provided w/ unit
� Calibration Certificate
� 0 - 10 VDC Input - CFM Setpoint
� 0 – 10 VDC Output - Measured CFM
� Alarm when CFM falls below setpoint
Pressure Signal Chart
text
Strategy 7.2 Continuously Monitor
and Control Outdoor Air Delivery
• Proper placement of airflow stations is critical
• Installing too close to an elbow or other
disrupting feature can affect performance
68
Air Measurement Station Placements for Acceptable Installations
Air Measurement Station Placements for Acceptable Installations
Air Measurement should be in the Mechanical Spec!
Air Measurement Station Placements for Acceptable Installations
90° DEGREE UNVANED ELBOW
5D 1D
Strategy 7.2 Continuously Monitor
and Control Outdoor Air Delivery
• Consider using airflow
measuring sensors
between fixed louver
blades
– Higher velocity, better
accuracy
20,000 CFM supply air measured
±±±±1,000 CFM @ 5% accuracy (S.A.)
16,000 CFM return air measured
±±±±800 CFM @ 5% accuracy (R.A.)
THE DIFFERENCE
Could be off by ±±±±1,800 CFM
Versus measurement at the intake
4,000 CFM @ 5% accuracy (O.A.)
±±±±200 CFM @ 5% accuracy (O.A.)
Air Flow Sensing Stations
Accuracy Considerations:Outside Air Measurement Advantage
Outside Air
Objective 8 Apply More Advanced
Ventilation Approaches
• Strategy 8.2 Use Energy Recovery Ventilation
Where Appropriate
– Required by ASHRAE 90.1 2007 & 2010 in some
cases
74
Code Driven Requirements
ASHRAE 90.1 2007 Energy StandardEnergy recovery is required on individual fan systems that are:
5000 cfm or greater, and
Outside air accounts for 70% or more of the design supply air quantity
Energy recovery system shall have 50% effectiveness:
Change in enthalpy equal to 50% of the difference between outdoor air and return air at design conditions
Status of Code Adoption: Commercial
www.energycodes.gov/adoption/states
As of February 2013
Most States are Expected to Adopt 90.1 2010 by End of 2013!
DOE Climate Zone Map – for 90.1
Miami FL
Houston, TX
Phoenix, AZ
San Francisco CA
Baltimore MD
Salem, OR
Chicago, ILBoise, ID
Burlington, VT
Helena MTDuluth, MN
El Paso, TX
Albuquerque, NM
Memphis TN
Figure B-1
How do Climate Zones affect ERV?
ASHRAE 90.1 2010 states:6.5.6.1 Exhaust Air Energy Recovery. Each fan system shall have an energy
recovery system when the system’s supply air flow rate exceeds the value listed
in table 6.5.6.1 based on the climate zone and percentage of outdoor air flow rate
at design conditions.
• Stretch standard for energy efficiency
• “Glimpse” of the future of 90.1
• Currently being specified for some
government buildings
• Requires even more energy recovery
• As low as 10% outside air requires energy
recovery in some cases
• The energy recovery effectiveness shall be
60%
ASHRAE 189.1 Standard
Energy Recovery
• ERV – Latent Recovery
– Energy Recovery Wheels
– Fixed Plate w/ Latent Transfer
• HRV – Sensible Only (no latent)
– Fixed Plate
– Heat Pipe
– Runaround Loops
80
Wheel ERV’s – How They WorkWheel Rotates between the
Return Air and the Outdoor Air
Airstreams
Return Air Temperature and
Humidity is absorbed onto the
Desiccant Wheel
Outdoor Air is tempered
(Heated/Cooled) as it flows
across the Wheel
Outdoor Air Humidity
Decreases or Increases as air
flows across the Wheel
Exhaust Air Transfer Ratio
EATR is the % of air being exhausted from
the occupied space that leaks around the
ERV wheel and re-enters occupied space.
Importance: Per ASHRAE 62.1……
Dedicated Duct System
Ducted to Rooftop Unit
Common ERV Configurations
UnitizedStand Alone
Typically 300 to 12,000 CFM
Small ERV’s – 150 to 1000 CFM
Only 18” to 22” tall!
Example of small ERV application
Small ERV Installation
Questions?
89
90
Thank You!