# Presentation: 490856

## Data Center CX

**Data Center CX**

- Mark Hydeman, P.E., FASHRAE Taylor Engineering, LLCmhydeman@taylor-engineering.com

## Data Center Cx Overview

- Roles and Responsibilities
- Cx Timeline
- Prefunctional Testing
- Functional Testing
- Trend Reviews
- Other Issues

## Commissioning

- Level of commissioning
- No “right” answer – it depends on amount owner is willing to spend vs. perceived and real benefit of a functioning system
- Typically follows 80-20 rule: 80% of benefit achieved with 20% of effort, and to eliminate the last 20% of problems requires 80% more effort
- Make the level appropriate for the building type and complexity of systems
- Non-critical:  Small retail and office
- More critical:  Large, complex buildings
- Most critical:  Data centers, central plants, labs

## Current Cx Practice

- Includes:
- Submittal review
- Post construction walk-through
- Typically no testing beyond T24
- Title 24 2005 requires some performance verification tests

## Comprehensive Cx

- Comprehensive Cx:
- 3rd party peer review of design and sequences
- Detailed submittal review
- Detailed programming review including simulations
- Prepare pre-functional and functional test forms
- Pre-functional test verification
- Perform functional tests
- All main systems
- Subset of repetitive systems (e.g. VAV boxes)
- Post-construction trend review
- Post-occupancy trend review
- Pre-warranty trend review
- Fully documented all steps and submit Cx report

## Who Does Commissioning

- Contractor
- Current practice
- Largely ineffective due to competitive pressures, lack of oversight
- Design engineer
- Most familiar with design, but often not sufficiently experienced with controls
- Cx not included in standard fees
- 3rd Party
- No conflict of interest, but most expensive and can be disruptive
- Combination of above
- Split work among various parties to minimize cost, take advantage of expertise
- Cx Plan must be clearly detailed in spec’s!

## Roles and Responsibilities

## Timeline (from EMCS Specification)

- Submit Submittal Package 1 (Hardware and Shop Drawings) and receive approval.
- Initiate installation of EMCS hardware, devices and wiring.
- Develop point database and application software.
- Simulate sequencing and debug programming off-line to the extent practical.
- Submit Submittal Package 2 (Programming and Graphics) and receive approval.
- Complete installation of EMCS hardware, devices and wiring.
- Install point database and application software in field panels.
- Submit Submittal Package 3 (Functional Testing) and receive approval.
- Perform EMCS Pre-functional Tests (start up, calibration and tuning) and submit Pre-functional Tests for approval.
- Field test application programs prior to functional testing.
- Receive EMCS Pre-functional Test Report approval and approval to schedule Functional Tests.
- Assist TAB contractor in TAB tests and determining setpoints as specified in Section 15950.
- Perform and record functional tests and submit Functional Test Report for approval.
- Submit Package 4 (Training Materials) and receive approval.
- Receive EMCS Functional Test Report approval and approval to schedule Demonstration Tests.

## Timeline, continued

- Perform Demonstration Tests to Commissioning Coordinator and Owner’s Representatives and submit Demonstration Test Report.
- Receive acceptance of Demonstration Tests.
- Train Owner personnel on EMCS operation and maintenance.
- Substantial Completion.
- Prepare and initiate commissioning Trend Logs.
- Submit Submittal Package 5 (Trend Logs) in format specified for review and approval.
- Receive approval of successful Trend Log tests, or retest as required.
- Complete all items in Completion Requirements
- Provide administration level password access to the Owner.
- Final Acceptance.
- Begin Warranty Period.
- Prepare and initiate post-occupancy Trend Logs.
- Two months prior to end of Warranty Period, submit Submittal Package 6 (Trend Logs) in format specified for review and approval.
- Receive approval of successful Trend Log tests, or retest as required.
- Revise and submit record documents and O&M Manuals.
- Update all software as specified.
- End of Warranty Period.

## Programming Review

- Not intended to debug programming
- Just to make sure specified sequences were actually followed
- Most contractors will use programming developed from previous jobs
- OK provided spec’d functionality is maintained

## Programming Review Example

## Programming Review Example

- Economizer is controlling to mixed-air temperature (MAT) not supply-air temperature (SAT)
- Economizer is controlled to a fixed 60F.  Specs call for the economizer to be controlled to reset SAT setpoint using same SAT PID loop controlling mechanical cooling
- Economizer is disabled when OAT > 68F.  Specs say it is disabled when outdoor air temperature exceeds the return air temperature

## Example Programming Review

## Prefunctional tests

- Augments and documents manufacturer’s start up procedures for equipment
- Includes some system testing like
- Pipe pressure testing
- Duct leakage testing
- Valve leakage tests
- May include factory witness testing (e.g. chillers)

## Control system pre-functional tests

- General
- Inspect the installation of all devices.
- Verify integrity/safety of all electrical connections.
- Verify that all sensor locations are as indicated on drawings
- Digital Outputs
- Verify DOs operate properly and that the normal positions are correct.
- Digital Inputs
- Adjust setpoints, where applicable.
- Analog Outputs
- Verify start and span are correct and control action is correct.
- Analog Input Calibration
- Calibrated as specified on the points list
- Inaccurate sensors must be replaced if calibration is not possible.

## Calibration Log

## Pre-functional tests, continued

- Alarms and Interlocks:
- Check each alarm separately by including an appropriate signal at a value that will trip the alarm
- Verify internal and external response to alarm (email, page)
- Gateways
- Verify operation and map across points
- Loop Tuning
- Achieve specified stability
- Operator Interfaces
- Verify that all elements on the graphics, functional and are bound to physical devices
- Verify hyperlinks
- Trending/Network Traffic Test
- TAB tests
- Setpoint Determination, e.g. DP and minimum outdoor air damper position

## Functional Tests

- Scope
- Test every sequence
- Test every unique subsystem and a subset of multiple subsystems (e.g. VAV boxes)
- Format
- Test form to include setup, steps, expected response, and actual response
- Who does prepares and performs tests?
- May be contractor, engineer, or 3rd party Cx agent
- We often have the engineer prepare and witness them and the contractor performs them

## Functional Tests

## Functional Tests

## More Functional Tests

- Shut off devicesand watch systemresponse  (e.g. startof backup pump)
- Check alarms andresponse
- Override setpointsand watch systemresponse
- Push system to extremes (full cooling/heating)
- Power system down and check recovery
- Observe system as it operates

## Trend Reviews

- Required even when detailed functional tests are performed
- Functional tests mimic control sequences – they prove programming matches sequences but cannot identify bugs in sequences
- Less expensive than comprehensive functional testing with proper analysis tools
- But trends do not generally show faults – they must be tested in the field since they may not occur during trend period
- Requires experienced eye – design engineer with controls experience who is very familiar with sequences and HVAC systems

## DDC Trend Reviews

- Collect Trends using DDC system
- Massage data
- Software tool enables import, normalization, sorting, grouping and exporting of trends
- Perform statistical analysis
- Graph selected variables
- Analyze results

## Time Series Static Pressure Reset

## Scatter Plot Loop Tuning, Reset

## Statistics

## Combination of Statistics, Time Series

## Pivot Table or Summation Query

## Other Cx Issues

- One person on site must coordinate all Cx activities
- Hold regular weekly Cx meetings
- Use of load banks
- Detail recovery procedures for testing on live data centers
- Carefully coordinate electrical, mechanical and control testing to save time and costs

## Best Practices for Cx

- Specify thorough commissioning for data centers
- Be specific on roles and responsibilities
- Have an experienced Cx Coordinator on the site
- Hold weekly Cx meetings with all trades represented
- Carefully coordinate electrical, mechanical and control system testing

## Resources

## General Resources

- ASHRAE (_http:\\www.ashrae.org_)
- Technical Committee (TC) 9.9 Mission Critical Facilities _[http://tc99.ashraetcs.org/](http://tc99.ashraetcs.org/)__ _
- Design Considerations for Datacom Equipment Centers
- Datacom Equipment Power Trends and Cooling Applications
- Thermal Guidelines for Data Processing Environments
- Additional Guidelines in Development (1/2007)
- TCO and Energy Efficiency
- High Density Data Centers
- Liquid Cooling
- Filtration
- Structural

## General Resources

- LBNL High Performance Buildings for High-Tech Industries (_[http://hightech.lbl.gov/datacenters.html](http://hightech.lbl.gov/datacenters.html)_)
- PG&E CoolToolsTM Chilled Water Plant Design Guide (_[http://taylor-engineering.com/publications/design_guides.shtml](http://taylor-engineering.com/publications/design_guides.shtml)_)
- LBNL High Performance Datacenters, A Design Guidelines Sourcebook (_[http://hightech.lbl.gov/documents/DATA_CENTERS/06_DataCenters-PGE.pdf](http://hightech.lbl.gov/documents/DATA_CENTERS/06_DataCenters-PGE.pdf)_)
- Electrostatic Discharge Association (_[http://www.esda.org/](http://www.esda.org/)_)
- Uptime Institute (_[http://www.upsite.com/TUIpages/tuihome.html](http://www.upsite.com/TUIpages/tuihome.html)_)
- Green Grid (_[http://www.thegreengrid.org/home](http://www.thegreengrid.org/home)_)
- EPA/Energy Star (_http://www.energystar.gov/index.cfm?c=prod_development.server_efficiency_)

## Control Resources

- DDC Online (_[http://www.](http://www.ddc-online.org/)__[ddc](http://www.ddc-online.org/)__[-online.org](http://www.ddc-online.org/)_)
- AutomatedBuildings (_http://www.automatedbuildings.com/_).  This site is an e-zine on building automation and controls.
- ASHRAE Guideline 13-2000, “Specifying Direct Digital Control System.”
- Control Spec Builder an on-line resource for developing control specifications (_http://www.CtrlSpecBuilder.com_)
-  National Building Controls Information Program (NBCIP, _http://www.buildingcontrols.org/_)

## Control/Cx Resources

- CSU Control and CX Guidelines (_[http://www.calstate.edu/cpdc/ae/guidelines.shtml](http://www.calstate.edu/cpdc/ae/guidelines.shtml)_)
- California Commissioning Collaborative (CaCx, _http://www.cacx.org_)

## Take Aways

- No “right” way to perform commissioning
- Comprehensive Cx involves many steps
- Various approaches—contractor, engineer, 3rd party, combo
- Commissioning plan must be in specifications
- Controls programming  should be reviewed
- Prefunctional and functional tests verify system and component function
- Trend reviews while not as comprehensive can identify problems
- Coordination is important during commissioning

## The End