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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

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2008 title 24 nonresidential hvac acceptance testing for building officials contractors

2008 Title 24 Nonresidential HVAC Acceptance Testing for Building Officials & Contractors

Presented by:

name

title

date

California Commissioning Collaborative


What this talk will cover
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


Overview
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


What is acceptance testing
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


Is acceptance testing needed
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


Who benefits from acceptance tests
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


Acceptance tests
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)


Resources
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


Acceptance chapter in nonresidential manual
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


Acceptance and compliance forms
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


Code enforcement process plans and specifications
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


Code enforcement process testing and inspection
Code Enforcement Process: Testing and Inspection

  • Installing contractor or other “eligible professional” conducts tests and fills out MECH-#Aacceptance 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


Designer has a big impact on ease and cost of acceptance tests
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


Key statements in mech 1c
Key Statements in MECH-1C tests

  • 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


Hvac acceptance tests
HVAC Acceptance Tests tests

Defined in Standards’ Mandatory Section 125

Detailed in the Appendix NA7

Nonresidential Compliance Manual

Test Descriptions in Chapter 10

Forms in Appendix A


Acceptance requirements 1 of 2
Acceptance Requirements (1 of 2) tests

Updated for 2008


New acceptance requirements 2 of 2 for compliance credit measures
New Acceptance Requirements (2 of 2) testsfor Compliance Credit Measures


Acceptance tests always applied to single zone rooftop units
Acceptance Tests Always Applied to Single Zone Rooftop Units tests

  • MECH-2A - Outdoor Air for CAV

    • Measured outside air within 10% of the values listed on MECH-3C

  • MECH-3A - Constant Volume & Single-Zone 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


Acceptance tests single zone rooftop units sometimes in order of likelihood
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


Acceptance tests always applied to variable air volume systems
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


Direct digital control to the zone
Direct Digital Control to the Zone Systems

  • 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


Acceptance tests frequently applied to vav systems with ddc to the zone
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


Acceptance tests usually applied to hydronic systems
Acceptance Tests Usually Applied to the Zoneto 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



5 to the Zone

CV RTU 1 to 5

2

VAV AHU 1 & 2

1

CHW System

Checks in red indicate tests that would always be done for these system types


What is an acceptable package of acceptance tests
What is an acceptable package of acceptance tests to the Zone

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”


T24 2008 hvac forms

Changes in 2008 to the Zone

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)

T24 2008 HVAC Forms


The not so fine print
The not so fine print to the Zone

  • 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??


New field inspection checklist
New Field Inspection Checklist to the Zone

  • 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


Installation certificate
Installation Certificate to the Zone

  • 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


Project information to the Zone(typical)

Technician block(typical)

Reviewer block(typical)

Acceptance forms end in “-#A”


People qualified to certify tests responsible person
People Qualified to Certify Tests to the Zone“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


California contractors typically eligible to take responsibility for acceptance tests
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


Construction inspection (typical) responsibility for acceptance tests

Functional Testing block (typical)


Test summary responsibility for acceptance tests(Typical)


Completed acceptance tests are a condition of the certificate of occupancy
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


Simple spot tests summer economizer
Simple Spot Tests – Summer Economizer Certificate of Occupancy

  • 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


Simple spot tests vav system summer
Simple spot tests VAV system – summer Certificate of Occupancy

  • 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


Minimum outdoor ventilation air acceptance mech 2a appendix na 7 5 1

Minimum Outdoor Ventilation Air Acceptance MECH-2A Certificate of OccupancyAppendix NA 7.5.1


Why is minimum outside air important
Why is minimum outside air important Certificate of Occupancy

  • 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


Outside air dampers
Outside air dampers Certificate of Occupancy

  • 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.


Purpose of outdoor air acc test
Purpose of Outdoor Air Acc. Test Certificate of Occupancy

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


Design minimum outside air mech 3c vav o office space vav a assembly space min o a in column i
Design Minimum Outside Air MECH-3C Certificate of OccupancyVAV-O = office space, VAV-A = assembly space, Min O/A in Column I

VAV-O 1,000 0.15 150 5 75 150 160 350 400 400 300 N/A

VAV-A 1,000 0.15 150 34 510 510 510 1,200 400 1,200 550 N/A

Totals 39 660 670 0

Min O/A for MECH-2A

67 x 0.5 = 34


Fixed minimum oa damper position only allowed for constant volume systems
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


Test procedure cv system
Test Procedure CV System volume systems

Disable economizer (if applicable)

Disable DCV (if applicable)

Measure and record OSA

Restore boxes, economizer and DCV controls

Setup

Test

Clean up


How to disable an economizer
How to Disable an Economizer volume systems

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)


How to disable and engage dcv controls
How to Disable and Engage DCV Controls volume systems

Disable DCV

Raise CO2 setpoint significantly above current CO2 reading (all controls)

Engage DCV

Lower CO2 setpoint to lowest possible setpoint (all controls)


How to measure osa
How to Measure OSA volume systems

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


Construction inspection
Construction Inspection volume systems

  • 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)


Vav acceptable o a control dual minimum
VAV Acceptable O/A Control volume systemsDual 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


Example method of dynamic osa control injection fan

Injection Fan w/ Discharge Damper volume systems

Outdoor Air Intake

Return Air

Example Method of Dynamic OSA Control: Injection Fan

Signal from SAT Controller


Example method of dynamic osa control fixed damper with dp control

Can be 1 section or entire OA damper volume systems

Example Method of Dynamic OSA Control: Fixed Damper with DP control

∆P correlated to flow for fixed orifice

Outdoor Air Intake

Return Air

Signal from SAT Controller


Test procedure vav system
Test Procedure VAV System volume systems

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

Combinetests to save time and $$

MECH-2A full airflow test with DCV disabled

MECH-6A. full airflow test with DCV enabled

Setup

Test 1

Test 2

Clean up


How to drive vav boxes open
How to Drive VAV Boxes Open volume systems

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


How to drive system to minimum airflow
How to Drive System to Minimum Airflow volume systems

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)


Project information volume systems(typical)

Technician block(typical)

Reviewer block(typical)


Project XYC, Somewhere, California volume systems

AH 1

2nd Floor Offices

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


Test summary volume systems(Typical)

Project XYC, Somewhere, California

AH 1

2nd Floor Offices


Reasons to reject the mech 2a
Reasons to Reject the MECH-2A volume systems

  • 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



Purpose
Purpose volume systems

Check thermostat, setpoints and scheduling controls

Verify that heating, economizer and cooling are properly sequenced

Verify operation in occupied and unoccupied modes


Mech 3a functional tests
MECH-3A Functional Tests volume systems

  • 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


Occupied mode test procedure
Occupied volume systems Mode Test Procedure

Heating

Supply fan operates continuously

OSA is provided

No cooling occurs

Verify that all heating stages work

Dead Band

Supply fan operates continuously

OSA is provided

No heating or cooling occurs

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


How to drive the unit into heating cooling or deadband
How to drive the unit into heating, cooling or deadband volume systems

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


Unoccupied mode test procedure
Unoccupied volume systemsMode Test Procedure

Heating

Supply fan cycles on with call for heating (and off when satisfied)

OSA is closed or cycles with supply fan

No cooling occurs

Dead Band

Supply fan is off

OSA damper is closed

No heating or cooling occurs

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


How to move the unit into unoccupied mode
How to move the unit into “unoccupied” mode volume systems

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


Override mode test procedure
Override volume systems Mode Test Procedure

Enable after hours override

System goes to “occupied” mode

System returns to “unoccupied” mode after timed delay

Return system to normal operation

Reset all setpoints

Remove any jumpers


How to activate the after hours override
How to activate the after-hours override volume systems

Put the unit into “unoccupied” mode (see previous slide)

Push the after-hours button on the thermostat


Air side economizer mech 5a

Air-Side Economizer volume systemsMECH-5A


Purpose1
Purpose volume systems

Check economizer installation and provision for exhaust or relief

Test economizer operation

When a call for coolingand it is cool outsidethe economizerbrings in outside air

Other times min O/A


Overview1
Overview volume systems

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


High limit switch
High Limit Switch volume systems


Economizer functional testing
Economizer Functional Testing volume systems

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


How to disable an economizer1
How to Disable an Economizer volume systems

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


Vav supply air acceptance test mech 7a
VAV Supply Air volume systemsAcceptance TestMECH-7A

Drawing courtesy of Steven Taylor


Purpose2
Purpose volume systems

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


Overview2
Overview volume systems

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


Construction inspection verify
Construction Inspection - Verify volume systems

  • 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.


Construction inspection1
Construction Inspection volume systems


Test procedure
Test Procedure volume systems

You may have to disable SA temperature reset during this test to prevent unwanted flow fluctuations

Drive boxes to achieve design airflow (refer to min OSA test for how to do this)

Record measured SP (must be +/- 10% of setpoint)

Note if fan speed stabilizes within 5 minutes


Test procedure1
Test Procedure volume systems

Drive boxes to achieve minimum airflow (refer to min OSA test for how to do this)

Record measured duct static pressure (must be +/- 10% of setpoint)

For DDC to zone systems, pressure setpoint must be reduced

Note if fan speed stabilizes within 5 minutes




Demand control ventilation requirements 121 c 4
Demand Control Ventilation Requirements (§121(c)4) volume systems

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


Do return co 2 sensors work
Do Return CO volume systems2 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


Purpose3
Purpose volume systems

Check DCV calibration and installation

Test DCV at:

High CO2 levels

Low CO2 levels


Related tests
Related Tests volume systems

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


Dcv test procedure
DCV Test Procedure volume systems

  • 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.


Overriding co2 controls
Overriding CO2 Controls volume systems

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


Default is 400 volume systemsppm


Duct sealing air distribution systems mech 4a

Duct Sealing volume systemsAir Distribution SystemsMECH-4A


Mech 4 a air distribution 144 k
MECH-4-A Air Distribution volume systems§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


Mech 4 a construction inspection
MECH-4-A Construction Inspection volume systems

  • 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


Mech 4a calculated supply fan flow
MECH-4A Calculated supply fan flow volume systems

  • Rated flow from capacity

    • 400 cfm/ton

    • 21.7 cfm/kBtuh heating only systems


Mech4 a leakage test new construction
MECH4-A Leakage Test New Construction volume systems

  • 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


Mech 4 a duct testing
MECH-4-A Duct testing volume systems


Mech 4a duct testing results new construction or alterations
MECH-4A Duct Testing Results volume systemsNew Construction or Alterations

New

Alterations


Mech 4 a duct sealing on retrofits 144 k 149 b 1d e
MECH-4-A Duct Sealing on Retrofits §144(k), 149(b)1D&E volume systems

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


Hers rater sampling test validation
HERS Rater Sampling Test Validation volume systems

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)


Automatic demand shed controls
Automatic Demand volume systemsShed Controls


Automatic demand shed controls 122 h
Automatic Demand Shed volume systemsControls (122(h))

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).

All New!


Overview3
Overview volume systems

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


Purpose4
Purpose volume systems

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


Automatic demand shed controls1
Automatic demand shed controls volume systems

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.


Beyond scope for today
Beyond Scope for Today volume systems

These tests are documented in the Non-Residential Appendices and Non-Residential Compliance Manual. They are only required when you seek a compliance credit.


Summary
Summary volume systems

  • 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


Sample questions
Sample Questions volume systems

  • 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?


More questions
More questions volume systems

  • 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?


Outdoor air acceptance test questions
Outdoor Air Acceptance Test Questions volume systems

  • Which compliance form contains the design ventilation air information?

  • Measured ventilation air cfm must be within what percentage of design ventilation air cfm?

    • 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?


Packaged a c acceptance test questions
Packaged A/C Acceptance Test Questions volume systems

  • 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:

    • Heating call, b) Cooling call, c) No call for either heating or cooling

  • When is the outside air damper completely closed?


Air side economizer test questions
Air-side Economizer Test Questions volume systems

  • 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.


Resources 2008 standard
Resources – 2008 Standard volume systems

  • Energy Efficiency Hotline

    • E-mail: [email protected]

    • Phone: 916-654-5106 or

    • Phone: 1-800-772-3300 (toll free in Calif.)


Acknowledgements
Acknowledgements volume systems

  • 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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