GSA Commissioning Guide (September 2020)

Overview

The guide describes the Total Building Commissioning process by which GSA's Public Buildings Service verifies the functionality of new construction and major modernizations. Following ASHRAE Guideline 0-2019, commissioning is a quality-focused process that verifies and documents that all commissioned systems and assemblies are planned, designed, installed, tested, operated and maintained to meet the Owner's Project Requirements (OPR). The guide follows project initiation, design, construction, and occupancy and operations. The primary audience is project managers, construction management advisors, the Commissioning Provider (CxP) and GSA's Office of Facilities Management.

For benefits it cites the U.S. Department of Energy 2018 Commissioning Cost/Benefit Study: commissioning existing buildings yields 3% to 10% energy savings, and new-construction commissioning yields a 13% median whole-building saving. Benchmark CxP fees run from 0.5% to 1.75% of construction cost for offices ($3.25-$5.00/GSF) to 0.90% to 2.50% for laboratories ($7.00-$10.00/GSF), and complexity, size and 24/7 operation affect them. In design, focused CxP design reviews are recommended at the end of Design Concepts, during Design Development (50%) and near the end of Construction Documents (95%).

In construction, functional performance testing begins where construction checklists end; it evaluates whether components work together to meet the OPR and is valid only once start-up and testing, adjusting and balancing (TAB) are done. Test records include a test reference, date and time, first test or retest, system identification, conditions (steady state), expected and observed performance, issues and signatures. Retest costs and delays should be the contractor's responsibility. For systems that cannot be tested at full load for seasonal reasons, such as a chiller and tower in winter, deferred and seasonal testing is planned for the operations phase.

In operations, at 10 months of a 12-month warranty period the CxP, the operations office and the CMa critically review systems. The CxP delivers a Final Commissioning Report that serves as a reference for future recommissioning. The guide also describes recommissioning and continuous commissioning programmes: targeted E4 BAS re-tuning at 83 GSA buildings (over 35 million ft2) yielded about 9% annual energy savings in the first year and 13% in the second. The Appendix B systems-selection matrix shows which systems are recommended for commissioning by building type (such as generators) and has a Data Center column.

The guide is a general building guide: it contains no data-center-specific test procedures or integrated systems test levels and reflects the organisation of U.S. federal projects (GSA, PBS-P100). Elements such as the OPR, basis of design (BOD), review milestones, test records and the roles-and-responsibilities matrix can still be adapted for any critical facility. Commissioning may call for separate plans for the building enclosure, fire and life safety, HVAC and landscape, which need different personnel.

Key points

1. Commissioning existing buildings saves 3-10% of energy, and new-construction commissioning gives a median 13% whole-building saving (DOE 2018 Cost/Benefit Study).
2. Benchmark CxP fees range from 0.5-1.75% of construction cost for offices ($3.25-$5.00/GSF) to 0.90-2.50% for laboratories ($7.00-$10.00/GSF).
3. CxP service costs are cited at $0.13-$0.48 per square foot for existing buildings and $0.40-$1.35 for new construction.
4. CxP design reviews are recommended at the end of Design Concepts, during Design Development (50%) and near the end of Construction Documents (95%).
5. Functional performance testing starts after construction checklists; components and start-up and TAB must be verified first.
6. Retest cost and delay are the contractor's responsibility to encourage construction quality; the Cx plan should state the number of retests and the protocol.
7. At 10 months into a 12-month warranty period the CxP, operations office and CMa review systems for warranty repairs.
8. Targeted BAS re-tuning at 83 GSA buildings (over 35 million ft2) yielded about 9% energy savings in year one and 13% in year two.
9. The Appendix B systems-selection matrix lists the systems recommended for commissioning by building type, including a Data Center column (for example, generators).
10. The guide is a general building guide with no data-center-specific test procedures or integrated systems test levels.

Using it in design

• Set up the commissioning plan at the start of a data center project: review the OPR and basis of design with the CxP and write measurable performance targets.
• Place CxP design reviews at the end of concept, the 50% and the 95% milestones, remembering that changes made early cost less than changes after installation.
• Add the commissioning budget to the first cost estimate, show services and testing separately and leave time and money for retests.
• Write functional test procedures and a test record template (conditions, expected and observed performance, signatures) into the specification, and assign retest responsibility to the contractor.
• For seasonal systems such as chillers and towers, and equipment that cannot be tested at full load, write deferred and seasonal testing and a payment holdback into the contract.
• Define data-center-specific integrated systems testing (electrical, cooling, controls) separately, since this guide does not cover it; use the Data Center column of the systems matrix as a starting point.

Who should read it

Project managers, designers and commissioning providers who set commissioning scope, budget and design-review milestones for data center or critical facility projects.

Document contents

1. Foreword
2. Introduction
3. Philosophy
4. Building Commissioning Process: Overview
5. Project Initiation Phase: Define Owner's Project Requirements with the Customer Agency
6. Develop Preliminary Commissioning Plan and Establish Initial Budget
7. Incorporate Commissioning into A/E and CMa Scopes of Services
8. Retain Commissioning Provider Services
9. Design Phase: Review Owner's Project Requirements and Basis of Design
10. Concept, DD and CD Design Reviews
11. Develop Commissioning Specifications
12. Construction Phase: Review Submittals and Oversee Functional Performance Testing
13. Conduct Owner Training and Turnover Commissioning Record
14. Occupancy and Operations Phase: Deferred and Seasonal Testing
15. Final Commissioning Report, Recommissioning and Ongoing Commissioning
16. Appendix A - Commissioning Roles and Responsibilities Matrix Template
17. Appendix B - Commissioning Systems Selection Matrix
18. Appendix C - Resources and References
19. Appendix D - Glossary and Definitions

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Publication details

Authors

U.S. General Services Administration, Public Buildings Service

Publisher

U.S. General Services Administration (Public Buildings Service)

Year

2020

Document language

English

Source type

Government / public

Access

Open licence — downloadable

Licence

U.S. public domain — U.S. Government work; free to reuse

Licence evidence

www.copyright.gov

Citation