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ASHRAE 90.1-2019 vs 2018 IECC: Mechanical
October 12, 2021
Providing effective energy strategies for buildings and communities
ICC Preferred Provider # 2396ICC Course # 29754
1. Understand the relationship between and organizational differences
in the IECC and ASHRAE 90.1
2. Understand differences between prescriptive HVAC and Service
Water requirements in the IECC and ASHRAE 90.1
3. Understand similarities between prescriptive HVAC and Service
Water requirements in the IECC and ASHRAE 90.1
4. Understand existing building HVAC and Service Water requirements
in the IECC and ASHRAE 90.1
Leaning Objectives
SEDAC is a Preferred Education Provider with the International Code Council (ICC). Credits earned on
completion of this program will be reported to ICC for ICC members. Certificates of Completion will be issued
to all participants.
This workshop is approved for 1.5 LU/HSW CES credits from the American Institute of Architects (AIA). Credits
earned on completion will be reported for AIA members.
The Smart Energy Design Assistance Center (SEDAC) is an applied research program at University of Illinois.
Our mission: Reduce the energy footprint of Illinois and beyond.
Who We Are
SEDAC is the Illinois Energy Conservation Code Training Provider
This training program is sponsored by
Illinois State Energy Office
Energy Code Training Program
Technical support [email protected]
Online resources at
smartenergy.illinois.edu/energy-code
www.smartenergy.Illinois.edu/energy-code/
Access to 2018 IECC, Illinois Amendments & Chicago Energy Conservation Code
https://codes.iccsafe.org/content/IECC2018P4 https://www2.illinois.gov/cdb/business/codes/IllinoisAccessibilityCode/Documents/2018%20Illinois%20Specific%20Amendments%20with%20Modifications%20Shown.pdf
https://codes.iccsafe.org/content/document/1491
Access to 2016 & 2019 ASHRAE 90.1
https://www.ashrae.org/technical-resources/standards-and-guidelines/read-only-versions-of-ashrae-standards
2019 2016
Free Preview Versions of ASHRAE Standards
Code. Are adopted as law by
authorities having jurisdiction over
the way buildings are constructed.
In Illinois, the State has adopted
the IECC.
The IECC has adopted ASHRAE
as a standard that can be used to
show code compliance.
IECC
Energy Code Compliance
Standard. In Illinois, ASHRAE is a
standard that can be used to show
compliance.
ASHRAE
Remember! You must choose one You must choose one path or the other – not allowed to
“cherry pick” requirements.
SEDAC 2021/2022 Fall Series Workshops
90.1-2019 vs 2018 IECC: Mechanical TODAY!
90.1-2019 vs 2018 IECC: Lighting and Electrical – 11/9/21
90.1-2019 vs 2018 IECC: Performance-Based Compliance – 12/14/21
Registration: https://smartenergy.illinois.edu/energy-code-training/webinars
Or: https://smartenergy.illinois.edu/energy-code/workshops/
Overview
2018 IECCASHRAE 90.1
2 routes to energy code compliance for commercial buildings in Illinois…
2 Paths:
Both Illinois law and the 2018 IECC allow ASHRAE 90.1 as an alternative path to
demonstrate compliance for commercial buildings.
2 Definitions
Organization - Overall
IECC1 Purpose, Scope, Admin, Etc.
Existing Buildings
C401. General
C402. Envelope
C403. Mechanical
C404. Service Water
Heating
C405. Electrical &
Lighting
C406. Additional
Efficiency Packages
C407. Total Building Performance
C408. Maintenance & Commissioning
Chapter 5
Components
Code Compliance
3 General Req.
3 & 4. Definitions, Admin, Etc.
Organization - Overall
ASHRAE1 & 2. Purpose & Scope
11. Energy Cost Budget Method
5. Building Envelope
6. HVAC
7. Service Hot Water
8. Power
9. Lighting
10. Other Equipment
3 & 4. Definitions, Admin, Etc.
Our Series – Register Today!
https://smartenergy.illinois.edu/
energy-code/workshops/1 & 2. Purpose & Scope
11. Energy Cost Budget Method
5. Building Envelope
6. HVAC
7. Service Hot Water
8. Power
9. Lighting
10. Other Equipment
Organization - HVAC
ASHRAE
Hint! Requirements are organized by the
chosen Compliance Path, not components.
1. Climate Zone Differences
Red counties moved to warmer CZ(Calhoun, Clark, Coles, Cumberland, Greene, Jersey)Green counties moved to cooler CZ
ASHRAEIECCZone 5 in IECC Zone 4 in ASHRAE
ASHRAE Additions not
in IECC
Like-for-like replacement, where compliance
would require extensive revisions to other
systems, equipment, or elements of a building,
compliance is not required.
ASHRAE
2. Like for Like Replacement
ASHRAE has a simplified compliance path.
This may be used if all of the following
applies:
• Building 2 stories or less
• Gross floor area less than 25,000 SF
• Each HVAC system complies with 6.3.2
ASHRAE
2. Simplified HVAC Path (6.3)
Single HVAC zones
Variable flow per 6.5.3.2.1 (Multi-stage fan above 5 tons)
Unitary packages or split-system with required efficiency
Air economizer
Exhaust air energy recovery per 6.5.6.1
Manual changeover or dual setpoint t-stat
Heat pump auxiliary heat minimization
ASHRAE
2. Simplified HVAC Path (6.3.2)
No reheat
Scheduled system operation w/ manual override
Hotel/Motel see 6.4.3.3.5 (50+ rooms)
Piping Insulation
Ductwork insulation per Table 6.8.2 and sealed
per 6.4.4.2.1
Air Balance required
ASHRAE
2. Simplified HVAC Path (6.3.2 cont.)
Outdoor Air and exhaust per 6.4.3.4
If separate heating/cooling systems, interlock
required preventing simultaneous operation
Design Capacity above 10,000 CFM requires
optimum start
DCV per 6.4.3.8, standby per 6.5.3.8,
ventilation per 6.5.3.7
Door switch per 6.5.10
ASHRAE
2. Simplified HVAC Path (6.3.2 cont.)
Photo Courtesy of Garage Doors Unlimited
Requires the following data:
• Blade span (diameter)
• Rated airflow and power @ max speed
ASHRAE
2. Large Diameter (>7’) Ceiling Fans
Photo Courtesy of RuppAir
Mechanical cooling shall not
reduce humidity below a
dewpoint of 55°F or relative
humidity of 60% in the coldest
zone whichever is lower
ASHRAE
Dehumidification
Fossil fuel or electricity shall not
be used to produce relative
humidity above 30% in the
warmest zone served by the
system
ASHRAE
Humidification
Photo Courtesy of Blackall Mechanical
Requires DDC for particular
applications and meeting
qualifications (See Table
6.4.3.10.1)
ASHRAE
Direct Digital Controls
Specifies minimum requirements
in 6.4.3.10.2
Zone 5A Zone 4AWater Cooled 1,500 tons 1,000 tonsAir Cooled 860 tons 570 tons
ASHRAE
Chiller Plant Monitoring
Requires electric and efficiency measurement recorded at least every 15
minutes for 36 months for chiller plants sized:
Photo Courtesy of Onset
Zones with only Auto-off lighting
controls, and 62.1 occupancy
permits ventilation to 0 when in
occupied-standby.
Shall do the following 5 min after
vacated:
ASHRAE
Occupied-standby
Heating & Cooling Setpoints
setback 1°F
Zero airflow when space in
deadband
Photo Courtesy of Lighting Controls Association
Where reheat is permitted and
supply & return openings are
above 6’ off floor, supply temp is
limited to not more than 20°F
above room temp
ASHRAE
Supply Temp Reheat Limit
Photo Courtesy of Barcol-Air
Preheating jackets shall be
automatically turned off when
humidification is not required
Dispersion-tube hot surfaces
insulated at least R-0.5
ASHRAE
Humidification
Preheat coils shall stop heat
output when mechanical cooling
is occurring
Photo Courtesy of AprilAire
Chilled water and Condenser
piping designed to limit velocity
per Table 6.5.4.6
Ranges from 5-13 ft/sec
depending on run time and if the
flow is variable or not
ASHRAE
Pipe Sizing
Photo Courtesy of Rocky Mountain Institute
Chilled water coils to have at
least 15F delta and leaving water
temperature of at least 57F at
design conditions
ASHRAE
Coil Selection
Exceptions for constant air
volume systems, smaller (5000
CFM or less) systems, and less
common applications.
Photo Courtesy of Froztec
• 1-10 mmBtu/h
• Excludes units of 300 kBtu or
smaller
• Return water must be limited
to 120F or below
High Capacity Space Heating
Chart Courtesy of Weil McLain
ASHRAE
• Different requirements for non-
transient dwellings. 60%
enthalpy recovery ratio at
winter design condition
ASHRAE
Exhaust Air Energy Recovery
Photo Courtesy of ERI Corporation
• Required for facilities that:
• Operate 24 hrs/day
• Design load exceeds 1
mmBtu/h
• Heat-rejection equipment of
water-cooled systems
exceeds 6 mmBtu/h
ASHRAE
Service Water Heat Energy Recovery
Condenser heat recovery shall
supply 7% of cooling capacity for
following conditions:
• Inpatient hospital operating
24/7
• Design CHW capacity >3.6
mmBtu/h
Space Conditioning Heat Recovery
ASHRAE• Simultaneous heating and
cooling occurs above 60F
OAT
• Indoor pools over 500 sf with
dehumidifiers shall have one
of the following:
ASHRAE
Pool Dehumidifier Energy Recovery
1. Exhaust sensible or total
energy recovery of at least
50%
2. Condenser heat recovery to
use 100% for pool heating
when needed
• Conditioned space with a door
opening to the outdoors shall
be provided with controls that
when door is opened:
ASHRAE
Door Switches
• Disable heating or lower
setpoint to 55F or lower
• Disable cooling or raise
setpoint to 90F or higher
• Excludes entries with
automatic closing devices
Photo Courtesy of Control By Web
• HVAC serving only a computer
room with load greater than
10kW shall use ASHRAE 90.4
Energy Standard for Data
Centers
ASHRAE
IT loads 90.4
• Has recommendations for
spaces indirectly conditioned
ie. return air plenums
ASHRAE
Duct Insulation – Indirectly Conditioned
ASHRAE & IECC
Comparisons
Addition served by existing HVACR systems
and equipment, existing equipment does not
need to comply.
New systems need to comply.
ASHRAE & IECC
2. Addition w/ existing Equipment
IECC
• At least 1 thermostatic control per zone
• 5°F deadband
• Programmable thermostat or BAS
• Setback controls
• Optimum Start for DDC systems
• Zone isolation
• Hotel/Motel guest room controls
ASHRAE & IECC
2. Mandatory Similarities
IECC
10°F heating setback
4°F for radiant system
5°F cooling setback
ASHRAE
Setback Temperatures
Setback to 55°F heating
Setback to 85°F cooling
IECC
Lumps setback and shutdown
together under one item: Timeclock
or programmable controls providing
7-day schedule.
2-hr override to be provided
10-hr back-up
No other options listed
IECC
Setback Control Options
ASHRAESplits setback from shut-down.
Setback is same as IECC
Shutdown includes following control
options:
• Occupancy sensor
• Manual timer w/ 2hr limit
• Interlock to security system
Space Temp
Occupied Setpoint
Outdoor Temp
Time to Occupancy
Floor Temp for radiant systems
ASHRAE
Optimum Start
Adjust start time in order to bring
space to desired temperature
immediately prior to scheduled
occupancy
IECC
Zone 4 – 10 cfm/ft2
Zone 5 – 4 cfm/ft2
ASHRAE
Motorized Damper Leakage
4 cfm/ft2
IECC
Photo Courtesy of Price Industries
Detect contaminants and
stage/modulate to 50% or less
capacity
ASHRAE
Enclosed Parking Garage Ventilation
Stage/modulate to 50% or less
capacity or;
Intermittently operate less than
20% of time (or as required to
maintain acceptable contaminant
levels)
IECC
Photo Courtesy of Greg Seiber
Exception for<30,000 SF or
1,500 SF/hp or more & no
heating or mechanical cooling
ASHRAE
Enclosed Parking Garage Ventilation
Exception for 1,125 CFM/hp or
more & no heating or mechanical
cooling
Exception for exhaust capacity
<22,500 cfm
IECC
Photo Courtesy of Blackrock HVAC
• Design Outdoor Airflow <750
cfm
• >75% of outdoor air is
provided for makeup for that
space or transferred to other
spaces for makeup
• Ventilation for specific
occupancy categories
ASHRAE
Demand Controlled Ventilation Exceptions
• Design Outdoor Airflow <1,200
cfm
• Supply minus makeup/transfer
<1,200 cfm
• Ventilation only for process
loads
IECC
Eliminate economizer
requirements by increasing
cooling efficiency by 42% in
Zone 4A and 49% in Zoner 5A
ASHRAE
Economizer Exception
Eliminate economizer
requirements by increasing
cooling efficiency by 20% in
Zone 4A
IECC
Uses Fan Efficiency Index
1.00 or higher
ASHRAE
Fan Efficiency
Uses Fan Efficiency Grade
67 or higher
IECC
Photo Courtesy of Rocky Mountain ASHRAEPhoto Courtesy of Greenheck
• 15% up to 240,000 Btu/h
• 10% above 240,000 Btu/h
ASHRAE
Hot Gas Bypass Limit
• 50% up to 240,000 Btu/h
• 25% above 240,000 Btu/h
IECC
Photo Courtesy of York Central
Hydronic systems with 3 or more
control valves must be variable
flow.
ASHRAE
Variable Flow Controls
Hydronic systems of 300,000
Btu/h or more must be variable
flow
IECC
Service Water Heating
• Equipment shall be sized per
manufacturer’s published
guidelines, engineering
standards and handbooks
acceptable to AHJ
ASHRAE
Service Water Heating Load Calculation
• 120F or lower as needed for
intended use
• 110F for public lavatories
ASHRAE
Service Water Heating Temp Limits
• Time switches or other
automatic controls to switch
off system during extended
periods when hot water not
required
ASHRAE
Temp Maintenance Controls
• More specific about start and
stop of pumps/maintenance
system. Clearer compliance.
IECC
• Required for heated pools
indoors or outdoors
• Pools heated above 90F must
have a cover of R-12 or better
unless 60% solar or site
recovered energy
ASHRAE
Pool Covers
• Required for outdoor heated
pools unless 75% energy over
the season is site recovered
energy
IECC
• Provides provisions if
equipment can serve both
space heating and service
water heating; At least one of
the following:
ASHRAE
Shared Equipment
• Low standby loss
• Demonstrated savings over
separate units
• Total capacity <150,000 Btu/h
• Supply volume limit:
• Public lavatory: 2 ounces
• All other: ½ gallon
Heated Pipe Length
IECC
Replacement Equipment needs to meet the same requirements as new
construction without requiring alterations to building systems outside the
scope of alteration or replacement
• I.e. Load calculation, Economizer, DCV, etc.
ASHRAE & IECC
Existing Buildings
IECC
