b e s l brooks energy & sustainability lab kristin heinemeier, ph.d., p.e. technical director...
TRANSCRIPT
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Kristin Heinemeier, Ph.D., P.E.Technical Director
Brooks Energy & Sustainability Lab
with Balaji Santhanakrishnan, Anita Ledbetter, Michael Martin, Dean Schneider,
Jim Shoop, Wes Harvey, Joseph Martin, Frank Thomas
12th National Conference on Building Commissioning
May 18, 2004
Metrics for Reporting Benefits of Commissioning
in New School Facilities
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Benefits of Commissioning
Reduce Operating Costs Energy O&M
Better Building Thermal comfort Indoor air quality
Better Process for Providing Building On time Within budget
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There is an urgent need for solid (non-anecdotal) data on the benefits of commissioning.
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Case Study into Benefits for Texas Schools
Funded by State Energy Conservation OfficeInvestigate the Feasibility of Commissioning in New School FacilitiesEmphasize BenefitsDevelop a Guide for other Texas Schools
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Possible Methodologies
Large Sample Size Statistically significant sample Expensive! What metrics to collect?
Carefully Controlled Side-by-Side Hard to find good comparisons A lot of variables to control How generalizable are results Still need metrics for comparison
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Methodology We Used
Exploratory, Not-So-Controlled Side-by-Side StudyMixture of Qualitative and Quantitative Methods Quantify, Estimate, Identify
Very detailed data collection
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Commissioned School
Northside ISD – San AntonioDean Krueger Elementary School 100,800 sqft 800 students ~$11,000,000 construction cost (est) Design started 2003 Expected Occupancy August 2005
MEP Commissioned by TSI
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Baseline School
Patricia Blattman Elementary School 80,000 sqft (a little smaller) 660 students (a little fewer) ~$10,400,000 construction cost
(est) (a little less) Design started 2001 Occupancy August 2003 Same architect, different
contractors
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Baseline School: Blattman Elementary School
source: www.nisd.net
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Baseline School: Blattman Elementary School
source: www.nisd.net
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Baseline School
From an uncommissionedschool we expected:
Chaos Upon First Occupancy
source: www.nisd.net
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Baseline School
But it’s a verygood school.
source: www.nisd.net
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Data Collection Methods
Interviews School District Staff (engineering,
construction, energy management, O&M) Architect, ME, GC, Subcontractors
Construction Documents Building Plans and Specs, Change Orders,
Requests for Information, Meeting Minutes
Work Order DataUtility Data, Interval Energy DataOccupant Surveys and InterviewsBuilding Walkthru, Observations
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Analysis Methods
Define Narrative of Design and Construction ProcessesModeling
Without Deficiencies
WithDeficiencies
WithDeficiencies
WithoutDeficiencies
Baseline Building
CalibratedSimulation
Adjusted Simulation
Identify Deficiencies
Identify Deficiencies
Commissioned Building
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Analysis Methods, cont.:Define and Tabulate Metrics
NumericClearly Defined, Unambiguous Easily Collected using Simple Data Collection MethodsNormalized for Different Size Schools (sqft or construction costs) and Other Factors Capture Benefits from Commissioning
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Request for Information
Formal Communication from Contractor to Design Team ask for clarification comment on items that may not work as
designed suggest alternative design
Are they good or bad? design was unclear or incorrect healthy communication between contractor
and designers
Metrics Number of MEP-related RFIs/10,000 sqft
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RFIs at Baseline School
92 RFIs submitted 22 related to MEP – 2.6/10,000 sqft
For MEP-related RFIs 0-32 days in review, 9 average
Several resulted in Change OrdersSeveral could have been addressed in Design Stage
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Change Orders
Work required by contractor differs from what was assumed during the bidding process unforseen circumstances change in requirements by designer or owner response to RFI
More expensive to do work as a change orderMetrics Number of MEP-related Cost / 10,000 sqft Cost (as % of construction costs)
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MEP-Related Change Orders at Baseline School
Number of Change Orders
Cost of Change Orders
drainage in playground 4 43,577$ gym air conditioning 2 24,322$
misc PLUMBING 10 11,099$ misc ELECTRICAL 10 4,820$
misc HVAC 3 3,693$ plumbing/HVAC conflicts 1 3,556$
ventilation for electrical room 1 2,497$ misc FIRE/SECURITY 2 1,409$
pressure valve 1 -$ weatherstripping on doors 1 -$
library dehumidifier 2 -$ TOTAL 37 94,973$
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Ex: Adding Ventilation as CO
41% of price
Prepare Opening in SR Ceiling Sheet Metal Labor: Reassignment of ManpowerTouch up Painted Ceiling Sheet Metal Labor: Concurrent OperationsMaterial Handling Sheet Metal Labor: Beneficial OccupancyClean Up Sheet Metal Labor: Site AccessPM Coordination Time CoordinationEstimating Time Drafting/As-Built DrawingsField Clerk TestingAs-built & Shop Drawings Administrative fee
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Punch List
Result of Inspection near end of construction All items must be addressed as part of
Substantial completion
Want this List as Short as Possible EVERYBODY wants to finish project, so
items may be ignored
Metrics number of MEP-related items on
punchlist/room
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MEP-Related Punch List at Baseline School
Total IssuesAvg. Issues /
Room Total IssuesAvg. Issues /
Room
Building A 69 3.0 82 2.5Building B 30 2.0 41 1.5Building C 59 2.2 56 1.7Building D 56 4.7 109 3.9
Mechanical Rooms - - 84 8.4TOTAL 214 2.6 372 2.8
GRAND TOTAL 586 2.7
Above Ceiling Inspections Final Punchlist
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ScheduleCx helps anticipate and eliminate schedule conflictsAddressing issues earlier rather than later, in design and constructionDefine Milestones: Beginning of Design End of Design/Beginning of Construction
(est/actual) End of Construction (est/actual)
Metrics % Slippage (actual duration/expected
duration)
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Schedule at Baseline School
Est. Act. DiffMilestones:
Design Begins (Schematic Design Review) 24-Jul-01Construction Begins (First Construction Meeting) 18-Mar-02 05-Mar-02 -13 daysConstruction Ends (Substantial Completion) 14-Apr-03 31-Jul-03 108 days
Duration (days):Design Phase 237 224 -5 %Construction Phase 405 513 27 %
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Cost
Cost of Designing and Building the Facility Can be Reduced Design Costs Construction Costs (including all
contingencies and change orders)
Metric $/sqft percent overrun:
bid / expected (how well design met cost expectations)
actual / bid (cost overruns during construction)
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Cost at Baseline School
Difference between Expected and Actual Design Cost -4%
Difference between Expected and Bid Construction Cost -5%
Difference between Bid and Actual Cost 1%
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Work Orders
Cx should Reduce Number of Service Calls and Cost of Service Calls Especially during early occupancy:
problems have already been addressed More maintainable building
Metrics Number and Cost of MEP-related
Service Calls in first year / 10,000 sqft
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Work Orders at Baseline School
Number of Work Orders
Cost of Work
Orders
Routine Maintenance 65 7,088$ Preventive Maintenance 27 898$
Warranty Issues 18 -$ Vandalism 5 537$
Contractor Support for Projects Not Initiated by Maintenance
5 466$
New Work 2 60$ TOTAL 122 9,049$
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Occupant Identified Problems
Occupants are a good judge of significance of problemsSurveys, interviews of principal, teachers, custodian, other staff, studentsShould be fewer occupant-reported problems, especially in early occupancyMetrics Number of Significant MEP-related
Problems reported in first year Judgement: what is significant?
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Occupant Identified Problems at Baseline School
5 Significant Problems Reported: AC in Gymnasium didn’t work Problems with Plumbing Window and Door Leaks Premature Ballast Failures Dusty Rooms
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Energy Use
Energy Use should be lower than Non-Commissioned SchoolMetric Site Btu/sqft for first year - %
below benchmark (CBECS regional) Other normalization:
Weather Computer labs, AC in Gym, pools
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Energy Use
Monthly Energy Use (first 6 months)
5.1 kBtu/sqft 30% Above District Average 10% Below CBECS South
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1
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Aug 03 Sep 03 Oct 03 Nov 03 Dec 03 Jan 04 Feb 04 Mar 04 Apr 04 May 04 Jun 04 Jul 04
Mo
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Use
(kB
tu/s
qft
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Gas
Elec
District Avg.
CBECS, South
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Summary of Metrics
Others to consider: callbacks, major deficiencies thermal comfort, IAQ,
RFIs Number of MEP-Related RFIs (per 10,000 sqft) 2.6 Average Number of Days in Review 9
Change Orders Number of MEP-Related Change Orders (per 10,000 sqft) 4.4 Cost of MEP-Related Change Orders (% of Construction Cost) 0.9%
Punchlist Average Number of MEP-Related Punchlist Issues per Room 2.7 Schedule Difference between Expected and Actual Duration of Design Phase -5.5%
Difference between Planned and Actual Duration of Construction Phase 26.7%Cost Difference between Expected and Actual Design Cost -4.2%
Difference between Expected and Bid Construction Cost -4.7%Difference between Bid and Actual Cost 1.2%
Post-Occ Eval. Number of Significant MEP-Related Issues Identified in First Year 5 *Work Orders Number of MEP-Related Work Orders in First Year (per 10,000 sqft) 14.5 *
Cost of MEP-Related Work Orders in First Year (per 10,000 sqft) 1,079$ *Energy Use Electricity (annual kBtu/sqft) 23.7 *
Natural Gas (annual kBtu/sqft) 7.0 ** = first six months
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Future Work Needed
How reliable are the metrics? How much natural variation is there?
What is the best normalization?What is the appropriate scope (eg, MEP)?How well do they really capture performance? How much effort does it take to collect them? Who can collect them?How much are they affected by judgement required?
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Application of Metrics
Include these types of metrics in case-study protocols eg, California Commissioning Collaborative
Large statistically-significant data collection efforts (combined efforts? BCA?)Compared to what? Need research on current practices in
building construction and metrics for performance of conventional buildings
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Thank you!Questions?
source: www.nisd.net