Acceptance Tests - Western HVAC Performance Alliance

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2008 Title 24 Nonresidential
HVAC Acceptance Testing
for Building Officials & Contractors
Presented by:
name
title
date
California Commissioning Collaborative
What this talk will cover
• Description of acceptance testing requirements
in 2008 Title 24
• The motivation behind the requirements
• How acceptance testing affects design and
specification practices
• How it impacts compliance documentation
• New responsibilities of the designer and the
contractor
• Impacts on plan review and inspection
Title 24 2008 Acceptance Testing
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Overview
• Building Efficiency a product of:
– Materials and equipment
– Installation and set-up
– Occupant patterns and control
• Traditional standards
– Specify materials, equipment, controls
– Law of diminishing returns for more efficient equipment
• 2008 Title 24 standards – Acceptance Tests
– Ensure equipment works as intended
Title 24 2008 Acceptance Testing
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What is acceptance testing?
• Two components of acceptance testing
– Construction inspection
• Is the specified equipment installed and calibrated?
– Functional performance testing
• Does the equipment work as intended?
• Tests designed to uncover specification, installation
or set-up problems
• Not replacing commissioning
– Commissioning = broader scope
Title 24 2008 Acceptance Testing
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Is acceptance testing needed?
• PIER Small Commercial HVAC survey*
• Small commercial buildings < 4 yrs old
– 64% of economizers failed
• Cooling energy increased by 37%
– 38% of supply fans cycling during occupancy
• Violation of Title 24
– 30% unoccupied fan operation
• Increase of fan and heating energy
– 8% no outside air
– 8% simultaneous heating and cooling
* http://www.energy.ca.gov/reports/2003-11-17_500-03-082.PDF
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Who benefits from acceptance tests?
• The designer
– System installed and controlled according to code design intent
– Reputation based on correct equipment operation
• The contractor
– Technician’s work is reviewed
– Fewer call-backs
• The owner
– Equipment works right the first time
– Energy cost savings
• Society
– Less pollution associated with reduced energy consumption
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Acceptance Tests
• Required self-certification that equipment
and systems were tested and work as
intended
• Requires someone with a license to sign
off on the testing (architect, engineer or
contractor)
• Only one test (air distribution efficiency)
requires 3d party verification
– Home Energy Rating Service (HERS)
Title 24 2008 Acceptance Testing
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Resources
• 2008 Standards (Title 24)
• 2008 Standards Nonresidential Appendices NA 7
– Reference – not needed for design or testing
• 2008 Nonresidential Energy Standards Compliance
Manual
– Chapter 4 – Mechanical Systems
– Chapter 10 – Acceptance Requirements
– End of Manual – Compliance and Acceptance Forms
• CEC Resources
– http://www.energy.ca.gov/title24/2008standards/
– CEC Bldg Standards Hotline 1-800-772-3300
Title 24 2008 Acceptance Testing
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Acceptance Chapter in Nonresidential Manual
• Overview of compliance process
• At-A-Glance – 2 page overview of test
– Purpose
 Estimated Time
– Benefits
 Warnings or Cautions
– Instrumentation  Test conditions
– Acceptance Criteria
• Detailed test description
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Acceptance and Compliance Forms
• Compliance forms
– Filled out by designer
– MECH-1-C (C for compliance)
– Reviewed by plans checker
• Acceptance Forms
–
–
–
–
–
Filled out by person conducting test
Reviewed by person with a license
Usually contractor, TAB or commissioning agent
MECH-1-A to MECH (A for acceptance)
Collected by Inspector prior to CO (Certificate of Occupancy)
• Forms in Appendix A of the Nonresidential Compliance
Manual
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Code Enforcement Process:
Plans and Specifications
• Compliance documentation with
equipment specification and forms
– MECH-1C lists all tests and which
equipment must be tested
– MECH-3C lists design minimum outside air
• Criteria for outside air tests (NJ.3.1 & 3.2)
• Plan checker reviews and approves or
asks for modifications
– All AC systems should be listed with
appropraite tests
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Code Enforcement Process:
Testing and Inspection
• Installing contractor or other “eligible
professional” conducts tests and fills out
MECH-#A acceptance forms
– Equipment fixed until it passes all tests
• Completed forms handed to inspector along
with other documentation
– Inspector makes sure documentation is filled out
correctly
– Incomplete documentation is returned to contractor
• Certificate of Occupancy granted when
building is in full compliance
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Designer has a big impact on ease and cost of
acceptance tests
• Designer clearly identifies tests
– Problem if covered equipment not specified
on MECH-1C form and later needs testing
• Designer specifies equipment
– Pre-calibrated equipment is cheaper
• Designer builds in test capabilities
– Test ports and pre-installed gauges
– Valves for isolating equipment
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Key Statements in MECH-1C
• The plans meet code
• I am qualified to sign these forms
• List of all mechanical acceptance tests
with blanks for:
– Equipment to be tested
– Checkboxes to indicate which tests apply to
the equipment listed
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HVAC Acceptance Tests
• Defined in Standards’ Mandatory Section
125
• Detailed in the Appendix NA7
• Nonresidential Compliance Manual
– Test Descriptions in Chapter 10
– Forms in Appendix A
Title 24 2008 Acceptance Testing
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Acceptance Requirements (1 of 2)
Standard
Section
Additional
Standard
Section
Certificate of
Acceptance
125(a)1
121
MECH-2A
125(a)2
122
MECH-3A
NA 7.5.3 Air Distribution
125(a)3
124, 144(k) or
149(b)1D
MECH-4A
NA 7.5.4 (Air-Side) Economizer
125(a)4
144(e)
MECH-5A
NA 7.5.5 Demand Control Ventilation
125(a)5
121(c)3&4
MECH-6A
NA 7.5.6 Supply Fan Variable Flow Controls
125(a)6
144(c)2
MECH-7A
125(a)7 & 8
144(j)2 or 3
MECH-8A
NA 7.5.8 Supply Water Temperature Reset Controls
125(a)9
144(j)4
MECH-9A
NA 7.5.9 Hydronic System Variable Flow Controls
125(a)7
144(j)6
MECH-10A
NA 7.5.10 Automatic Demand Shed Controls
125(a)10
122(h)
MECH-11A
ACM Section and Test
NA 7.5.1.1 Variable Air Volume Systems Outdoor Air
NA 7.5.1.2 Constant Volume Systems Outdoor Air
NA 7.5.2 Constant Volume Packaged HVAC Systems
NA 7.5.7 Valve Leakage Test
Updated for 2008
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New Acceptance Requirements (2 of 2)
for Compliance Credit Measures
Additional
Standard
Section
ACM Section and Test
Standard
Section
NA 7.5.1.11 FDD for Packaged DX Systems
125(a)11
MECH-12A
NA 7.5.1.12 FDD for AHUS and Zone Terminal Units
125(a)12
MECH-13A
NA 7.5.1.13 Distributed Energy Storage DX AC
Systems
125(a)13
MECH-14A
NA 7.5.1.14 Thermal Energy Storage Systems
125(a)14
MECH-15A
Title 24 2008 Acceptance Testing
Certificate of
Acceptance
17
Acceptance Tests Always Applied to
Single Zone Rooftop Units
• MECH-2A - Outdoor Air for CAV
– Measured outside air within 10% of the values
listed on MECH-3C
• MECH-3A - Constant Volume & SingleZone Unitary
– Verifies that sequence of operation is correct
•
•
•
•
Setup and setback works
Fan turns off – unoccupied period
When fan off – O/A damper closed
No simultaneous heating and cooling
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Acceptance Tests - Single Zone Rooftop
Units – sometimes in order of likelihood
• MECH-5A - Economizer Controls
– Only if the unit has an economizer
• MECH-6A - Demand Control Ventilation
– Required for high density applications
• Retail (first floor)
• Auditoriums
• Schools are specifically exempt
• MECH-4A - Air Distribution Ducts
– Duct leakage test
– Only if > 25% of duct surface area outdoors or in
ventilated attic (not plenum)
– Change-outs ducts not inc conditioned space
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Acceptance Tests Always Applied to
Variable Air Volume Systems
• MECH-2A - Outdoor Air for VAV
– Measured outside air within 10% of the values
listed on MECH-3C at high and low flowrate
• MECH-7A Supply Fan VAV
– Fan slows down at lower loads
– For DDC to zone, duct pressure drops
• MECH-5A - Economizer Controls
– Systems over > 75,000 Btu/h required to have
an economizer
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Direct Digital Control to the Zone
• System has a central automated control
that receives feedback from all zones
– Allows pressure reset of variable flow fans or
pumps
• Pressure dropped until most open damper or coil
valve is almost full open. Thus all zones have
enough pressure.
– Allows resetting of zone temperature in
response to a utility signal (demand response)
– Allows adjusting outside air in response to
CO2 level in zones
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Acceptance Tests Frequently Applied to
VAV Systems with DDC to the Zone
• MECH-11A Automatic
Demand Shed Control
– Setup in response to utility
signal
• MECH-6A Demand Control
Ventilation
– Required for high density
applications
• Retail (first floor)
• Auditoriums
• Exempted: Schools, healthcare,
social service
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Acceptance Tests Usually Applied
to Hydronic Systems
• MECH-8A - Valve Leakage Test
– Check isolation valves on
boilers and chillers
– Test all valves on rest of system
• MECH-10A - Hydronic System
Variable Flow Control
– Under low coil load, fan speed
drops
– Under low coil load, system that
is DDC to zone, pressure drops
• MECH-9A - Supply Water
Temp. Reset
– Reset required only for systems
> 500,000 Btu/h.
– If system has controls, test
required
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Compliance forms end in “–C”
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CV RTU 1 to 5
VAV AHU 1 & 2
CHW System
5
2
1










Checks in red indicate tests that would always be done for these system types
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What is an acceptable package of
acceptance tests
• All Acceptance Tests listed on MECH-1C
are completed
• All signature blocks legible and signed
• All values filled in & specific to equipment
– Identical values for all tests indicate tests not
being conducted
• All tests should be “Passed”
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T24 2008 HVAC Forms
Changes in 2008
• Revisions to MECH-1C Certificate of
Compliance
• New Field Inspection Checklist
• New Installation Certificate
(10-103(a)3A)
• Reorganized Acceptance Test Forms
(Certificates of Acceptance)
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The not so fine print
• Systems Acceptance. Before occupancy permit is
granted …
• … all control devices shall be certified as meeting the
Acceptance Requirements
• Systems Acceptance. Before occupancy permit is
granted. All newly installed HVAC equipment must be
tested using the Acceptance Requirements.
• The MECH-1C form is not completed and is not to be
accepted by the building department unless the correct
boxes are checked.
• The building inspector must receive the properly filled
out and signed forms before the building can receive
final occupancy.
• Do you see a pattern??
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New Field
Inspection
Checklist
• Filled out by designer or Title
24 documentation author
(or automatically by
compliance software)
• Used by field inspector to
help identify critical
components
Title 24 2008
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Installation
Certificate
• Completed by licensed
person responsible for
building construction or
installation of the mechanical
system
• Certifies that installed
system meets code
requirements
There is no longer
a MECH 1A Form!
Title 24 2008
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Acceptance forms end in “-#A”
Project
information
(typical)
Technician
block
(typical)
Reviewer
block
(typical)
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People Qualified to Certify Tests
“Responsible Person”
• California licensed engineer, or architect
– Eligible under Division 3 of the Business &
Professions Code ... to take responsibility for
the scope of work
– Mechanical and civil engineers
• California licensed contractor
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California Contractors typically eligible to
take responsibility for acceptance tests
•
•
•
•
•
•
•
•
•
•
A General Engineering Contractor
B General Building Contractor
C-4 Boiler, Hot Water Heating System Fitting Contractor
C-20 Warm-air Heating, Ventilation & Air Conditioning Contractor
C-36 Plumbing Contractor
C-38 Refrigeration Contractor
C-43 Sheet Metal Contractor
D-62 Air and Water Balancing
C-10 Electrical Contractor (controls)
C-7 Low Voltage Systems Contractor (controls)
• Other contractors with related classifications
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Construction
inspection
(typical)
Functional
Testing block
(typical)
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Test summary
(Typical)
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Completed acceptance tests are a
condition of the Certificate of Occupancy
• Late installation of a given piece of
equipment is no excuse
• All other equipment can be tested and a
conditional permit granted for the late
piece of equipment
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Simple Spot Tests – Summer Economizer
• Have contractor place all AC in cooling
mode in early morning
– All economizers should be open
• Have contractor place in heating mode
– All economizers should be closed
• Have contractor place systems back in
cooling mode
– All economizers should close when it is hot
out
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Simple spot tests VAV system – summer
• Have contractor set cooling setpoint low
– Fan speed should increase – listen or look at
VFD output
• Have contractor set cooling setpoint high
– Fan speed should decrease
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Minimum Outdoor Ventilation Air
Acceptance MECH-2A
Appendix NA 7.5.1
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Why is minimum outside air important
• Too little O/A – sick building syndrome
– Often too little O/A at low flow for VAV
systems
• Too much O/A – huge energy penalty
– Hot summer day - 3 tons extra cooling for
each 1,000 cfm excess outside air.
• Without adjusted O/A – easily 100%
excess outside air
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Outside air dampers
• When in heating mode or in cooling mode
where bringing outside air would increase
load on building…
• ….outside air dampers are set or
controlled to allow the minimum outside air
needed to protect health and dispel normal
odors.
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Purpose of Outdoor Air Acc. Test
• Verification of minimum OutSide Air (OSA)
as scheduled on plans
• Verification that minimum OSA is provided
throughout the range of operation in a
VAV system and at design for CV systems
• Measured CFM of minimum outside air at
min flow and full flow must be within 10%
of design CFM on MECH-3C
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Design Minimum Outside Air MECH-3C
VAV-O = office space, VAV-A = assembly space, Min O/A in Column I
VAV-O 1,000
0.15
150
5
75
150
160
350
VAV-A 1,000
0.15
150
34
510
510
510
1,200
Totals
39
660
670
400
400
300
400 1,200
550
N/A
N/A
0
Min O/A for MECH-2A
67 x 0.5 = 34
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Fixed Minimum OA Damper Position only
allowed for constant volume systems
For VAV systems does NOT WORK since
mixed air plenum pressure varies!! Outdoor
air flow will vary proportional to supply air
flow
Outdoor
Air Intake
Minimum
Signal Pot.
Return Air
Signal from
SAT Controller
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Test Procedure CV System
Setup
Test
Clean up
1.
2.
3.
4.
Disable economizer (if applicable)
Disable DCV (if applicable)
Measure and record OSA
Restore boxes, economizer and DCV
controls
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How to Disable an Economizer
• Drop high-limit control setpoint below
current OA temperature or enthalpy (all
controls), or
• Raise OA temperature or enthalpy reading
above high limit control setpoint (DDC
controls), or
• Disable economizer control block (DDC
controls)
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How to Disable and Engage DCV Controls
• Disable DCV
– Raise CO2 setpoint significantly above
current CO2 reading (all controls)
• Engage DCV
– Lower CO2 setpoint to lowest possible
setpoint (all controls)
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How to Measure OSA
• AFMS (air flow monitoring station)
– If part of the system
•
•
•
•
•
Calibrated damper (if part of the system)
Traverse of OSA louver/duct
Traverse of SA and RA ducts (differential)
For each test OSA must be +/-10% of design
Note: on small packaged units you might have to
provide a temporary sheet metal hood on the
OSA intake to get a good reading
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Construction Inspection
• Calibration of AFMS or calibrated damper
(if part of the system)
• Verify that there is a provision for dynamic
control of OSA (if VAV)
• Verify that there is a provision for minimum
OSA (if CV)
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VAV Acceptable O/A Control
Dual Minimum
• Minimum damper position is set
proportionally based on fan speed
between setpoints determined when the
fan is at full speed and minimum speed
• Low cost
• Affected by wind, stack effect, filter loading
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Example Method of Dynamic OSA
Control: Injection Fan
Injection Fan w/
Discharge Damper
Outdoor Air
Intake
Return Air
Signal from SAT Controller
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Example Method of Dynamic OSA
Control: Fixed Damper with DP control
Can be 1 section or
entire OA damper
∆P correlated to flow
for fixed orifice
Outdoor Air
Intake
Return Air
Signal from SAT Controller
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Test Procedure VAV System
Setup
Test 1
Test 2
Clean up
1.
2.
3.
4.
5.
6.
7.
8.
Disable economizer (if applicable)
Disable DCV (if applicable)
Drive all boxes to minimum airflow
Measure and record OSA
Drive all boxes to design airflow
Measure and record OSA
Restore boxes, economizer and DCV controls
System passes if measured OSA in steps 4 & 6
are within 10% of design OSA
Combine tests to save time and $$
– MECH-2A full airflow test with DCV disabled
– MECH-6A. full airflow test with DCV enabled
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How to Drive VAV Boxes Open
• Set zone cooling temperature setpoint below the
current zone temperature (all controls)
• Override the VAV box airflow setpoint (DDC
controls)
• With DDC controls you might want to specify
preset functions to drive all boxes to design
airflow and minimum airflow to speed up the
tests
• Note: if you override the VAV box damper you
may provide more than the design maximum
airflow
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How to Drive System to Minimum Airflow
• Set zone cooling temperature setpoint
above the current zone temperature (all
controls)
• Override the VAV box control airflow
setpoint (DDC controls, could be preset)
• Manually slow down fan until airflow is
~30% of design airflow (all controls,
requires AFMS or duct traverse)
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Project
information
(typical)
Technician
block
(typical)
Reviewer
block
(typical)
Title 24 2008 Acceptance Testing
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Project XYC, Somewhere, California
2nd Floor Offices
AH 1
Construction
inspection
(typical)




1,850
2,000
3 mins

Testing block
(typical)
1,910
2,000
3.2 mins

92.
5
95.5
Title 24 2008
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Project XYC, Somewhere, California
AH 1

Title 24 2008 Acceptance Testing
2nd Floor Offices
Test
summary
(Typical)
58
Reasons to Reject the MECH-2A
• Signatures or names are missing for
technician or reviewer
• Ratio of measured flowrate to design
outside air flow rate (Percent OSA)
– >110%
– <90%
• Suspicious if all tests:
– Measured airflow equal to design airflow rate
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Packaged HVAC
Controls MECH-3A
Title 24 2008 Acceptance Testing
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Purpose
• Check thermostat, setpoints and
scheduling controls
• Verify that heating, economizer and
cooling are properly sequenced
• Verify operation in occupied and
unoccupied modes
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62
MECH-3A Functional Tests
• Simulate various operating modes
– Heating load occupied, no-load occupied, heating
load unoccupied, no load unoccupied, etc.
– Each condition is a column on the table
• Check for various HVAC unit responses
– Different responses represented by each row
– Areas grayed out are incorrect responses
– Areas with check boxes are correct responses
• Test and fix until under each operating mode
only responses are those indicated by check box
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64
Occupied Mode Test Procedure
1. Heating
–
–
–
–
Supply fan operates continuously
OSA is provided
No cooling occurs
Verify that all heating stages work
2. Dead Band
– Supply fan operates continuously
– OSA is provided
– No heating or cooling occurs
3. Cooling
–
–
–
–
Supply fan operates continuously
OSA is provided
No heating occurs
Verify that all cooling stages work
Note the cooling test is repeated under economizer acceptance
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How to drive the unit into heating,
cooling or deadband
• Cooling
– Move thermostat cooling setpoint below the current
room temperature
• Dead Band
– Move the thermostat cooling setpoint above the
current room temperature, and
– Move the thermostat heating setpoint below the
current room temperature
• Heating
– Move the thermostat heating setpoint above the
current room temperature
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66
Unoccupied Mode Test Procedure
4. Heating
– Supply fan cycles on with call for heating (and off when satisfied)
– OSA is closed or cycles with supply fan
– No cooling occurs
5. Dead Band
– Supply fan is off
– OSA damper is closed
– No heating or cooling occurs
6. Cooling
– Supply fan cycles on with call for heating (and off when satisfied)
– OSA is closed or cycles with supply fan
– No heating occurs
Again, the cooling test is repeated under economizer acceptance
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How to move the unit into “unoccupied”
mode
• Adjust the schedule so that the unit is
scheduled off at the current time, or
• Reset the current time so that it is outside
of the scheduled occupied period
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68
Override Mode Test Procedure
7. Enable after hours override
– System goes to “occupied” mode
– System returns to “unoccupied” mode after
timed delay
8. Return system to normal operation
– Reset all setpoints
– Remove any jumpers
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69
How to activate the after-hours override
• Put the unit into “unoccupied” mode (see
previous slide)
• Push the after-hours button on the
thermostat
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Air-Side Economizer
MECH-5A
Title 24 2008 Acceptance Testing
71
Purpose
• Check economizer installation and
provision for exhaust or relief
• Test economizer operation
• When a call for cooling
and it is cool outside
the economizer
brings in outside air
• Other times min O/A
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72
Overview
• References
–
–
–
–
Standard Sections §144(e) and §125(a)4
Form MECH-5A
Non-Residential Appendix NA 7.5.4
Nonresidential Compliance Manual 10.6.10
• Scope
– All new systems with air-side economizers
– No functional testing required if economizer is factory
installed and certified operational
• None certified currently
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High Limit Switch
Title 24 2008 Acceptance Testing
75
Economizer Functional Testing
Step 1: Disable demand control ventilation (DCV) systems (if applicable)
Step 2: Enable the economizer and simulate a cooling demand
– Economizer damper is 100 percent open and return air damper is 100 percent
closed.
– For systems > 75,000 Btu/h economizer is integrated
•
100 % open when the cooling demand can no longer be met by the economizer alone.
– All applicable fans and dampers operate as intended to maintain building
pressure.
– The unit heating is disabled.
Step 3: Disable the economizer and simulate a cooling demand.
– Economizer damper closes to its minimum position.
– All applicable fans and dampers operate as intended to maintain building
pressure.
– The unit heating is disabled
Step 4: Simulate a heating demand and set the economizer so that it is
capable of operating (i.e. actual outdoor air conditions are below lockout
setpoint).
– The economizer is at minimum position
Step 5: Restore DCV systems and remove all system overrides
Title 24 2008 Acceptance Testing
76
How to Disable an Economizer
• Drop high-limit control setpoint below
current OA temperature or enthalpy (all
controls), or
• Raise OA temperature or enthalpy reading
above high limit control setpoint (DDC
controls), or
• Disable economizer control block (DDC
controls)
• Do the opposite to enable economizer
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78
VAV Supply Air
Acceptance Test
MECH-7A
Drawing courtesy of Steven Taylor
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79
Purpose
• Check calibration and setpoint of pressure
sensor for VAV systems
• Check stability of control on VAV systems
at full and part load
• Make sure fan speed slows with reduced
load, supply air pressure does not rise
• For DDC to zone system, system air
pressure drops at reduced load
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80
Overview
• References
– Standard Sections §144(c)2B, C & D and §125(a)6
– Non-Residential Appendix 7.5.6
– Nonresidential Compliance Manual 10.6.14
• Scope
– New VAV fans greater than or equal to 10 hp
– Both prescriptive and performance approach
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81
Construction Inspection - Verify
•
•
Discharge static pressure sensors are either
factory calibrated or field-calibrated.
The static pressure location, setpoint, and
reset control meets the requirements of
§144(c)2C and §144(c)2D.
–
Sensor Location so set point < 1/3 the total design
static P (i.e. near the end of the duct)
•
–
–
except for DDC to zone systems w/ pressure reset
If located below major duct splits, sensors in each
major branch, take lowest value for control
DDC to Zone, Set Point Reset.
•
•
pressure set point based on the zone w/ most need
zone damper needing most pressure is nearly wide open.
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Construction Inspection
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Test Procedure
You may have to disable SA temperature reset
during this test to prevent unwanted flow
fluctuations
1. Drive boxes to achieve design airflow (refer to
min OSA test for how to do this)
2. Record measured SP (must be +/- 10% of
setpoint)
3. Note if fan speed stabilizes within 5 minutes
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Test Procedure
4. Drive boxes to achieve minimum airflow (refer
to min OSA test for how to do this)
5. Record measured duct static pressure (must
be +/- 10% of setpoint)
6. For DDC to zone systems, pressure setpoint
must be reduced
7. Note if fan speed stabilizes within 5 minutes
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Functional Performance Testing
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Demand Control
Ventilation (DCV)
MECH-6A
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Demand Control Ventilation Requirements
(§121(c)4)
• Where DCV is applied, it must meet the following:
– One sensor for each space that meets the criteria of 121(c)3B
– Sensor must be CO2
– Sensor must be located in the breathing zone between 3’ and 6’
AFF or at the anticipated level of the occupant’s heads
– Maintain setpoint of 600ppm + OSA ppm
• 400 PPM default or
• dynamically measured
– No greater than design ventilation @ 15 cfm/person
– No less than ventilation from Table 121-A (cfm/ft2)
– Design ventilation for spaces without DCV
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Do Return CO2 Sensors Work?
Return is diluted by other
Zones and does not track
the critical zone
No. Separate sensors are needed in each high density space
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Purpose
• Check DCV calibration and installation
• Test DCV at:
– High CO2 levels
– Low CO2 levels
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Related Tests
• NA 7.5.1 Outdoor Air Acceptance
• NA 7.5.4 (Air-Side) Economizer
Acceptance
This test should be combined with
minimum OSA and economizer
acceptance tests to reduce time and costs
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DCV Test Procedure
•
•
Disable economizer controls
Measure CO2 concentration
– If dynamic control < 600 ppm above ambient concentration
– Default ambient concentration 400 ppm, indoor air < 1,000 ppm
•
Step 1:Simulate a signal at or slightly above the CO2 concentration setpoint
required by §121(c)4C. Verify and document the following:
– For single zone units, outdoor air damper modulates open to satisfy the total
ventilation air called for in the Certificate of Compliance.
– For multiple zone units, either outdoor air damper or zone damper modulate
open to satisfy the zone ventilation requirements.
• Not required to have cfm greater than MECH-3C column I (design ventilation air cfm)
•
Step 2: Simulate signal well below the CO2 setpoint. Verify :
– For single zone units, outdoor air damper modulates to the design minimum
value.
– For multiple zone units, either outdoor air damper or zone damper modulate less
open to satisfy the reduced zone ventilation requirements.
• CFM must be at least as much as MECH-3C Column D (Min CFM by Area) for DCV
controlled zone + MECH-3C column I (design ventilation air cfm) for uncontrolled zones
•
Step 3: Restore economizer controls and remove all system overrides
initiated during the test.
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Overriding CO2 Controls
• To simulate high demand you need to
decrease the sensor setpoint
• To simulate low demand you need to
increase the sensor setpoint
• Best accuracy results from using
calibrated gas
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Default is 400 ppm
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Duct Sealing
Air Distribution Systems
MECH-4A
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MECH-4-A Air Distribution §144(k)
• Small (<5,000 sf) CV systems only
• When > 25% of duct surface is outdoors
or in unconditioned space
• Place greater than 75% of ducts under
insulated roof – test not needed
• Ducts must be tested for duct leakage
…. and verified as sealed by a HERS
rater
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MECH-4-A Construction Inspection
• Drawbands
– Stainless steel worm drive or
– UV resistant nylon duct ties
• Duct leakage tests performed before access is
blocked
• Duct tape not used unless with drawbands and
mastic
• R-8 insulation
• Outdoor insulation protected from damage
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MECH-4A Calculated supply fan flow
• Rated flow from capacity
– 400 cfm/ton
– 21.7 cfm/kBtuh heating only systems
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MECH4-A Leakage Test New Construction
• Seal all diffusers
• Pressurize system to 25 Pa (0.1 in WC)
with fan with calibrated orifice (duct
blaster)
• Measured leakage no greater than 6% of
rated flow
• Likely conducted by HVAC contractor
• Verified by HERS rater
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MECH-4-A Duct testing
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MECH-4A Duct Testing Results
New Construction or Alterations
New
Alterations
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MECH-4-A Duct Sealing on Retrofits
§144(k), 149(b)1D&E
Applies to small CV system with ducts outside or in
unconditioned spaces when:
– Ducts replaced
– HVAC system is replaced or major repair (new
compressor, new coil etc.)
Existing duct leakage
– ≤15% of rated supply flow
– >60% reduction of leakage prior to sealing ducts with
all visible leaks sealed
– Can’t get at the ducts and all visible leaks are sealed
as certified by a HERS rater
• Exceptions
– Asbestos
– Existing ducts that were previously certified
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HERS Rater Sampling Test Validation
• All systems must best tested by person conducting
acceptance tests
• Independent HERS rater verifies results through
sampled re-testing of systems:
– Verify the first system tested
– Verify one out of the each group of 7 tested
• If that unit fails the test,
• test a second unit in the group of 7
• if that fails test the other 5 in the group of 7
– Certify ALL of the tests made by the contractor
– Enter all tests into the HERS database
• New groups of 7 applies to each new construction
project (but not for retrofit)
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Automatic Demand
Shed Controls
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Automatic Demand Shed
Controls (122(h))
All
New!
• For systems with DDC to the zone:
– Ability to reset thermostat setpoint up to 4°F on all “non-critical”
zones through real or virtual DI.
– System needs an adjustable rate of change for reset
• Shown by LBNL and Purdue to reduce on-peak demand
by over 30%.
• Supported by ASHRAE Standard 55
(Table 5.2.5.2).
Time Period
1/4 h 1/2 h 1 h
2h
Maximum Operative
Temperature Change Allowed
2.0°F
5.0°F 6.0°F
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4h
107
Overview
• References
– Standard Sections §122(b)4, §122(h) and
§125(a)10
– Non-Residential Appendix NA 7.5.10
– Nonresidential Compliance Manual 10.6.19
• Scope
– New DDC Zone Controls
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Purpose
• To make sure that the demand shed
controls are programmed and work when
engaged
• Demand shed controls gives the owner the
opportunity to temporarily turn up t-stats in
all non-critical areas 4F a few hours per
year.
– Utility financial incentives
– Less likely to have a black-out
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Automatic demand shed controls
• NA7.5.10.1 Construction Inspection
• Prior to Acceptance Testing, verify and document the
following:
– That the EMCS interface enables activation of the central
demand shed controls.
• NA7.5.10.2 Functional Testing
• Step 1: Engage the global demand shed system. Verify :
– Cooling setpoint in non-critical spaces increases by the proper
amount.
– Cooling setpoints in critical spaces do not change.
• Step 2: Disengage the global demand shed system.
Verify :
– Cooling setpoint in non-critical spaces return to their original
values.
– Cooling setpoint in critical spaces do not change.
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Beyond Scope for Today
ACM Section and Test
Standard Section
NA 7.5.1.11 FDD for Packaged DX Systems
125(a)11
NA 7.5.1.12 FDD for AHUS and Zone Terminal Units
125(a)12
NA 7.5.1.13 Distributed Energy Storage DX AC Systems
125(a)13
NA 7.5.1.14 Thermal Energy Storage Systems
125(a)14
These tests are documented in the Non-Residential
Appendices and Non-Residential Compliance
Manual. They are only required when you seek a
compliance credit.
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Summary
• Acceptance tests assure that design intent for energy
savings is executed
• All heating and cooling systems have at least one
associated acceptance test
• The designer identifies which tests get applied to
which equipment on the MECH-1-C form
• Plans examiner reviews MECH-1C form to assure all
equipment has applicable tests specified
– Compliance forms are rejected and returned to applicant if all
applicable HVAC systems and tests are not called out
• Fully COMPLETED acceptance test forms with all
systems PASSING must be given to inspector before
building receives Certificate of Occupancy.
– Schedule a challenge test if results are suspicious
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Sample Questions
• Which compliance form lists all acceptance tests
that must be conducted?
• Who can be a “responsible person” for the
acceptance tests?
• Are acceptance tests a requirement for a
certificate of occupancy?
• Which acceptance test requires a third party
HERS verification?
• Are any tests valid without 3d party verification?
• What is done if a system does not pass an
acceptance test?
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More questions
• What tests are always required on
constant air volume systems?
• What tests are always required of VAV?
• What tests are usually required of VAV
systems with DDC to the zone?
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Outdoor Air Acceptance Test Questions
•
•
Which compliance form contains the design
ventilation air information?
Measured ventilation air cfm must be within
what percentage of design ventilation air cfm?
a) 5%, b) 10%, c) 30%, d)50%
•
For VAV, variable air volume, systems outside
air must be measured at design (full) flow and
at what other supply air flowrate?
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Packaged A/C Acceptance Test Questions
• Select all true answers below
When is supply fan on during occupied hrs:
a) Heating call, b) Cooling call, c) No call for
either heating or cooling
When is supply fan on during unoccupied hrs:
a) Heating call, b) Cooling call, c) No call for
either heating or cooling
•
When is the outside air damper
completely closed?
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Air-side Economizer Test Questions
• True or False
– Economizer open when call for cooling and
outside air temp is below high limit setpoint
– Economizer is open when call for heating and
outside air temp is below high limit setpoint
– Economizer closed when call for cooling and
outside air temp is above high limit setpoint
– Construction inspection not required for
factory installed economizer w/ CEC
certification.
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Resources – 2008 Standard
• Energy Efficiency Hotline
– E-mail: [email protected]
– Phone: 916-654-5106 or
– Phone: 1-800-772-3300 (toll free in Calif.)
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Acknowledgements
• California Commissioning Collaborative
• Pacific Gas & Electric Company
– Codes & Standards Program
• California Energy Commission
– Tav Commins, Project Manager
• Mark Hydeman, Taylor Engineering
• Jon McHugh, McHugh Energy Consultants
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