IV.D. - Program Development Study 1.pdf

January 29, 2016 Final Report PDN Number: EP-GS-P-01-16-BW-7166

EDWARD T. GIGNOUX FEDERAL COURTHOUSE

PORTLAND, MAINE

Prepared For: Prepared By:

General Services Administration Thomas P. O’Neill, Jr., Federal Building 10 Causeway Street, Room 1100 Boston, MA 02222

Edward T. Gignoux Federal Courthouse HVAC Upgrades PDS Report

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TABLE OF CONTENTS

TABLE OF CONTENTS

EXECUTIVE SUMMARY

Scope

Primary Purpose

Concerns and Expectations

Implementation Strategy

Critical Delivery Dates

Project Budget

Work Item Summary Table

Third Party Sign‐Off Sheet

BUSINESS PLAN

Assets and Goals

Design Alternatives

Report Quality and Cost Control

Planned and Ongoing Projects

Return on Investments

GENERAL BUILDING REQUIREMENTS

Operations/Services

PROGRAM GOALS

Sustainable Design

Efficient Operations and Maintenance

Innovative Technologies

Life Cycle Cost Analysis

BUILDING SYSTEMS

Work Item 1: Relocate Basement Outside‐Air Intakes

Work Item 2: Upgrade Air Handling Units and Distribution

Work Item 3: Building Automation System Replacement

Work Item 4: Relocate Remote Radiator for Emergency Generator

Work Item 5: Rooftop Fall Protection Upgrades

Work Item 6: Smoke Control System Upgrades

Work Item 7: Heating Plant ‐ Ground‐Source Heat Pump System

Work Item 8: Remove Rooftop Condensing Units

Work Item 9: Remove Abandoned Domestic Water Entrance

Demolition and Abatement

Utilities

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IMPLEMENTATION PLAN

Government Approvals

Utilities and Special Systems

Building Operation

Environmental Impact

Construction Phasing

BUDGET ANALYSIS

General

Estimated Construction Costs

Professional Services

APPENDICES

Appendix A – Photos

Appendix B – Cost Estimates

Appendix C – Life Cycle Cost Analysis

Appendix D – Sketches

Appendix E – Cutsheets

Appendix F – Calculations

Appendix G – Existing Mechanical System Documentation

Appendix H – Programming Contacts List

Appendix I – List of References

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EXECUTIVE SUMMARY

Scope The Architect‐Engineer (A‐E) is preparing a Program Development Study (PDS) for HVAC Upgrades at the Edward T.

Gignoux Federal Courthouse, Portland, Maine.

The Edward T. Gignoux U.S. Courthouse is a three story masonry structure constructed in 1911 and is listed on the National Registry of Historic Places. A major extension to the east side of the building was added in 1932. A modernization project was completed in 1996 – in addition to the construction of a new district courtroom, magistrate courtroom, and grand jury facility, the building’s HVAC and electrical systems were fully modernized. Between 2012 and 2013 the entire exterior building envelope was restored – exterior masonry, roof systems, window glazing, minor interior repairs, sprinkler system, and below grade waterproofing work was performed.

The primary Design Program scope items are as follows:

Evaluate and recommend solutions to relocate the air intake dampers

Evaluate existing Air Handling system in the Courthouse and identify any repairs or replacement needed.

Identify, Contrast and Compare replacing the existing Building Automation System.

Evaluate and recommend solutions to relocate a remote radiator for emergency generator set from rooftop to a lower level.

Evaluate and recommend options to install rooftop protective railings or tie‐offs needed for gutter cleaning.

Evaluate and recommend solutions for the existing smoke sensor locations and smoke exhaust controls.

Identify, Contrast and Compare the Boiler System for installation/replacement in the building.

Provide schedule and cost estimate for the demolition of two old/unused condenser units on the roof.

Provide schedule and cost estimate for the removal of old/abandoned water piping coming from the street in the basement mechanical room.

Identify/Evaluate any/all energy rebate programs that may be applicable.

Identify General Requirements and design directives for each building system.

Primary Purpose The PDS phase provides GSA with a sound foundation to pursue the construction funding and design start for this project. During the PDS phase, the project team, customer agency, and stakeholders use the PDS to develop the HVAC Upgrades project in greater detail. The PDS reviews and revalidates (or revises) all previous project assumptions, plans, and budgets. It will propose an estimated construction budget and implementation strategy for the project.

Concerns and Expectations Input from stakeholders is being used to understand the customer agency, local context, stakeholders’ concerns, and opportunities. Installing new systems in an occupied building of this magnitude may involve phasing, night work, and may influence which equipment is recommended. Ultimately the first choice will be based on the return on investment of the proposed systems and then the complexities of the installation will be considered.

Implementation Strategy The PDS includes an implementation strategy for the project. The plan’s purpose is to guide project phasing, construction procurement, and risk management. The Implementation Strategy considers workplace performance goals, impacts to the historic building façade, space requirements, sustainable design and energy usage targets, updated security and flood‐proofing requirements for the installed equipment, compliance with historic preservation and

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environmental laws, and recommended coordination with local plans. The implementation strategy identifies the proposed delivery method and all critical implementation issues/procedures.

Critical Delivery Dates Critical delivery dates are included as part of the Implementation Strategy. It identifies key project milestones, stakeholders, funding sources, and uncertainties about or risks to the project’s delivery. It also proposes the project delivery method and assumptions. The dates may include phasing and swing space requirements, potential agency interruptions, utilities coordination, construction phasing, and building turnover plans. It may also describe required stakeholder funding approvals, plus strategies for meeting environmental, historic preservation, and urban development requirements.

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Work Item Summary Table The following table is a summary of the recommended work items as presented in this report:

Work Item Description

Energy Cost

Savings per Year

Pay Back Period

Construction Duration

(excludes pre‐ construction and project closeout)

Total ECC Notes

Work Item 1: Relocate Outside Air (OA) Intakes

Work Item 2: Upgrade Air Handling Units (AHUs) and Distribution

Work Item 3: Building Automation System (BAS) Replacement

Work Item 4: Relocate Remote Radiator for Emergency Generator

Work Item 5: Rooftop Fall Protection Upgrades

Work Item 6: Smoke Control System Upgrades

Work Item 7:

Heating/Cooling System – Boiler Plant and Geothermal Evaluation

Work Item 8: Remove Rooftop Condensing Units

Work Item 9: Remove Abandoned Domestic Water Entrance

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Third Party Sign‐Off Sheet The purpose of this sheet is for GSA regional program office and principal client agencies to indicate their agreement to the project scope, implementation roles, and funding responsibilities.

Contracting Officer: Kathryn Thomas

Project Manager: John Maurer

Portfolio Management (Reg): Bryan Hodgkins

Property Manager: Tom Severance

Design and Construction (Reg): Janice Ramsey

HVAC Advocate (Reg): Waikit Lui

Electrical Advocate (Reg): Noretta Lleshi

Energy Goal Coordination: Sarah Wenninger

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BUSINESS PLAN

Assets and Goals The goal of this project is to reduce building energy consumption for heating, ventilating, and air conditioning (HVAC) systems, reduce overall system maintenance, comply with current GSA codes and standards, simplify building operations, and to extend the life of these systems to ensure future occupant safety and comfort.

Design Alternatives

Work Item 1: Relocate Outside Air (OA) Intakes Work Item 2: Upgrade Air Handling Units (AHUs) and Distribution Work Item 3: Building Automation System (BAS) Replacement Work Item 4: Relocate Remote Radiator for Emergency Generator Work Item 5: Rooftop Fall Protection Upgrades Work Item 6: Smoke Control System Upgrades Work Item 7: Heating/Cooling System – Boiler Plant and Geothermal Evaluation Work Item 8: Remove Rooftop Condensing Units Work Item 9: Remove Abandoned Domestic Water Entrance

Planned and Ongoing Projects Planned and ongoing projects that CCE is aware of, based on discussions with the GSA and field observations, are as follows:

Chiller Replacement Project – ongoing construction, anticipated to be operational by summer 2016

Judges’ Chambers Interior Space Alteration (ISA) – ongoing design, awaiting mold remediation prior to developing further analysis

Building Mold Remediation – ongoing, anticipated to be completed soon

The Work Items in the PDS Report factor these projects into the analysis as follows:

Work Item 2 considers that the interior of ductwork and air handling units will be inspected and cleaned as part of the on‐going building mold remediation effort. The Judges’ Chambers ISA will also be factored into evaluation of the air distribution in the second floor Judges’ Chambers.

Work Item 3 accounts for new BACNet DDC controllers installed as part of the Chiller Replacement Project when considering integration into a new Building Automation System (BAS)

Work Item 5 considers the new chiller equipment on the roof in evaluating fall protection

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We are not aware of any other scope of work overlaps with ongoing or future projects at the Gignoux Courthouse. The Chiller Replacement Project will seek rebates from Efficiency Maine for installing high efficiency chillers and pump VFDs, which were available during the design phase of the project.

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GENERAL BUILDING REQUIREMENTS

Operations/Services

Extended Warranties An extended warranty should be considered for new air handling units and heat pumps, if offered by the manufacturer.

The air handling units (AHUs) investigated for this report can come with an extended 2‐year or 5‐year parts warranty.

There are also varying labor warranties offered for the packaged AHUs. The heat pumps investigated for this report can come with an extended 5‐year parts warranty from the shipment date.

The Energy Recovery Ventilators (ERVs) investigated for this report offer a standard two year warranty for the overall unit and a five‐year warranty for the enthalpy wheel. There is no extended warranty available.

Maintenance Services The GSA currently contracts with CMC Mechanical Services (CMC) to provide on‐site facilities maintenance. CMC performs most of the preventative maintenance and repairs at the Gignoux Courthouse but does not do major repairs or provide specialty services, such as water treatment.

Alternative Energy Tie‐Ins There are no existing alternative energy systems tied in to the building.

As this PDS is an investigation into the existing and potential replacement HVAC systems, alternative energy systems in support of the recommended upgrades were investigated.

The Gignoux Building roof consists of approximately 15,000 square feet of area that could potentially be utilized for a 100 kW solar photovoltaic (PV) system.

Solar thermal domestic hot water heating was not evaluated for this project. The main domestic hot water load is from restroom handwashing and the demand is variable depending on the courtroom occupancy levels on any given day.

With such a relatively small domestic hot water load, we would not anticipate the payback on a solar thermal domestic hot water system to be favorable. If solar thermal panels were installed on the roof, new glycol supply and return piping would need to be routed to the basement in order to reach the existing domestic hot water distribution system. A new indirect‐fired domestic water heater with two coils – one for the solar thermal input and a back‐up coil that ties to the existing boilers – would be required.

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PROGRAM GOALS

Sustainable Design This project seeks to meet the GSA’s standards and federal requirements for reductions in building energy consumption.

If LEED certification is desired, CCE recommends that GSA retain a specialized consultant to manage and administrate the certification process.

Energy Efficiency Work Item 2 would reduce building energy consumption through the installation of more efficient air handling units and modifications to the existing system. Work Item 3 would provide a new Building Automation System (BAS) which would improve system efficiency throughout the building.

Energy analysis for the work items have been performed for this submission with Trane TRACE 700. Energy modeling inputs and current preliminary results are included in Appendix F. The design phase of this project shall include more detailed computer‐based energy modeling to confirm that the systems that are ultimately chosen will meet the GSA’s target energy reduction goal. All energy modeling is performed in accordance with the GSA’s PBS‐P100 standards.

Energy rebates and incentives are currently offered through the Efficiency Maine program. The incentives and rebates vary each year so it is unknown what types of credits the GSA may be eligible for when these projects move forward into construction. Currently there are incentive programs for the following Commercial Building upgrades:

Electricity Savings: Annual reductions of 350,000 kWh or more o The Electricity Savings incentive is not feasible for the work outlined in this PDS. An annual reduction of

350,000 kWh roughly equates to a daily reduction of 1,000 kWh. Given that the building’s function and operation are not scheduled to be affected by this work, the work of this PDS alone is not enough to realize 1,000 kWh/day in electricity savings.

Greenhouse Gases: Annual reductions of 500,000 pounds of CO2 o For the Gignoux Courthouse, the energy model shows that a geothermal system does not qualify for the

Greenhouse Gases incentive program.

There are also prescriptive incentives for the following upgrades:

Modulating Burner Control – Work Item #7

Boiler Economizer – Work Item #7

Boiler Reset/Lock Out Controls ‐ Work Item #7

Oxygen Trim Controls ‐ Work Item #7

Boiler Tabulator ‐ Work Item #7

Programmable Thermostat – Work Item #3

Gas‐Fired Tankless Water Heater ‐ (New condensing gas‐fired DWH installed in 2010)

Water Conservation This project does not include the replacement of plumbing fixtures or propose to reduce water usage inside the building.

Thermal Integrity/Moisture Protection There were historical issues with moisture intrusion into the exterior walls of the building but these issues have since been corrected and there are no known issues at this time with thermal integrity and moisture protection. Building envelope thermal images were taken on September 18, 2015 during the afternoon when the outdoor temperature was approximately 80 degrees Fahrenheit. The building envelope appears to be in good condition and properly sealed. See Appendix A for the thermal images.

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Efficient Operations and Maintenance All new equipment recommended for installation will reduce operations and maintenance, particularly the new air handling units recommended in Work Item 2. However, the ERVs investigated in Work Item 2, while reducing building energy consumption, will increase O&M needed for the building. The geothermal system in Work Item 7 would also increase O&M requirements.

Building Automation Work Item 3 proposes replacement of the existing outdated BAS with a new GSA‐compliant BAS utilizing BACNet protocol. This will greatly improve operations in the building as the current BAS is often unreliable and doesn’t allow for consistent monitoring and control due to its age.

Durability and Maintainability All equipment evaluated as replacement Work Items will be heavy commercial or light industrial grade to meet the durability requirements for the HVAC and plumbing services in the building. Air handling units and pumps will have expected service lives of at least 20 years and 15 years, respectively. All systems will be maintained by full‐time facilities personnel and separate contracts will need to be maintained for specialty services, such as water treatment.

Innovative Technologies The installation of a geothermal heat pump system at this building, as studied in Work Item 7, would represent an innovative technology that goes above and beyond the project requirements. Based on the energy model and as described in Work Item 7, the installation of a geothermal heat pump system is not a good fit for the Gignoux Courthouse.

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BUILDING SYSTEMS

Work Item 1: Relocate Basement Outside‐Air Intakes Existing Air Intakes: The existing outdoor air intake louvers for HVAC‐1, HVAC‐2, HVAC‐3, and MAU‐1 are located in basement mechanical spaces along the exterior of the building. The two (2) 60”X26” outdoor air intake louvers serving HVAC‐3 are located along Pearl Street (East façade). The four (4) 48”X56” outdoor air intake louvers serving HVAC‐1 and HVAC‐2 are located along Federal Street (North façade). The two (2) 48”X25” outdoor air intake louvers serving MAU‐1 are located along Market Street (West façade). These outdoor air intake locations are a security concern and do not comply with P‐100 (Facilities Standards for the Public Buildings Service) 2015, Section 5.3.3.2.

The existing outdoor air intake hood for HVAC‐4 is located on the Southwest corner of the roof. This air intake location complies with P‐100.

Existing Air Exhausts: The existing exhaust air louvers for HVAC‐1 are located in basement mechanical spaces along the exterior of the building. The two (2) 48”X56” exhaust louvers serving HVAC‐1 are located along Pearl Street (East façade). The exhaust vent hood serving HVAC‐2 is located on the Northeast section of the roof, near the existing cooling towers. The exhaust vent hood serving HVAC‐3 is located on the Southeast section of the roof, which was relocated from the original location near the existing cooling towers. The exhaust vent hood serving HVAC‐4 is located on the Northwest section of the roof. There is no dedicated exhaust for MAU‐1.

Work Item 1: This work item involves relocating the outdoor air intakes for HVAC‐1, HVAC‐2, HVAC‐3, and MAU‐1 to the roof level and reconfiguring the associated ductwork to accommodate the new location. All new and reconfigured ductwork shall be provided with new insulation in accordance with ASHRAE Standard 90.1. Relocating these air intakes will bring the facility into compliance with P‐100. Refer to Work Item #1 Sketch (Appendix D) for existing and proposed configurations. The exhaust locations on MSK‐105 shall be installed with backdraft dampers to ensure they are not used as an outdoor air intake. Rooftop exhaust fans will be installed to provide better control for the air handling systems.

Two (2) existing rooftop vent hoods, serving HVAC‐2 and HVAC‐3, will be removed and replaced by the exhaust fans.

Currently, the air handling units are able to operate in economizing mode without any pressurization issues.

The reconfiguration of the outdoor air intakes involves new ductwork to be located within existing vertical shafts in the Eastern portion of the building. Colby Company gained access into the vertical shafts at the basement level, second floor, and third floor by means of access panels and transfer ducts. Refer to Appendix A for photos and Appendix D for sketches with respect to the following discussion.

There is a larger shaft towards the South end of the building, and a smaller shaft towards the North end of the building.

These will be referred to as the North shaft and South shaft. The North shaft is continuous from the basement slab to the roof deck, with the exception of the second floor which divides the shaft into two. There is ample free space within the North shaft until it reaches the second and third floors. On the third floor just below the roof deck, there is only one

5.3.3.2 Outdoor Air Intake Locations (P‐100):

The placement and location of outdoor air intakes must be in compliance with the ISC (Interagency Security Criteria).

On buildings more than 12 m (40 ft.) tall, intakes must be located a minimum of 12 m (40 feet) above grade. On buildings less than 12 m (40 ft.), the intakes must be located as high as practical on the roof or on a wall. Table 6‐2 provides requirements for minimum separation distances between ventilation air intakes and other building features.

Outdoor air intakes must be ducted directly to the AHU cabinet; the equipment room must not be used as an outdoor air intake plenum.

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open area of approximately 30‐Inches by 30‐Inches. This opening can be used for an outdoor air duct serving HVAC‐3.

The remaining area of the North shaft is used by piping, ductwork, and associated components (See MSK‐106). The South shaft is continuous from the basement slab to the roof deck. There is no available space within the South shaft (See MSK‐106), which is fully utilized by existing supply and return ductwork.

Surrounding areas and rooms along the North and South shaft were evaluated for possible shaft expansions or new shafts. The janitor closets, adjacent to the North Shaft, have a significant amount of piping, pumps, ductwork, etc. (see the photo in Appendix A). Based on the existing configuration and use of the janitor closets, the space is not useable for new ductwork. The vestibules on the first, second, and third floors are all used as access into the courtrooms. A direct vertical path from the basement to the roof is unattainable, unless significant work is done to reconfigure the vestibules (Vest 256 and Vest 363) on the second and third floors and the entrance into the second floor courtroom (Rm 258). New floor penetrations and reconfiguration of existing piping, ductwork, electrical, etc. would also be required in order to achieve this. Based on the complexity of this work and the historic nature of the building, it is not recommended to make these alterations.

HVAC‐1 uses the South shaft to provide supply air to the spaces, and uses the North shaft as a return plenum to return the air back to the air handling unit. As discussed above, the outdoor air intake and exhaust are located at the basement level. The following two (2) options were evaluated for relocating the outdoor air intake for HVAC‐1 (refer to Appendix D for sketches).

Option A involves relocating the outdoor air intake exhaust vent to the roof level above the vertical shafts. A new outdoor air intake duct would be routed within, or in the vicinity of, the North shaft. The North shaft would also be used as a return/exhaust air plenum. However, based on the existing conditions (previously discussed) and the size of the outdoor air duct, it is not recommended to pursue Option A.

Option B involves relocating the outdoor air intake to the exterior courtyard wall (See Photo in Appendix A) and relocating the exhaust vent to the roof level. The ductwork along Pearl Street and the ductwork along Federal Street would be removed. The louvers would remain and be insulated and blanked‐off. New outside air ductwork, airflow measuring stations, and motorized dampers will be installed to serve HVAC‐1. To comply with P‐100, the outside air duct must be routed directly to the air handling equipment. The duct within the courtyard will be extended 40 feet above grade to satisfy P‐100. The duct will be routed from within the courtyard, to the North shaft, and to the return fan (RF‐1). All exterior ductwork will not be visible from the street level. This work involves one (1) roof penetration for the exhaust, removal and reconstruction of shaft walls and ceilings, a penetration through the exterior courtyard wall, and ductwork along the courtyard wall. New ductwork will be installed to connect Return Fan 1 (RF‐1) to HVAC‐1. Option B is feasible and satisfies P‐100.

The International Mechanical Code (Section 401.4) allows outdoor air intakes to be located above parking lots provided that the opening are located not less than 25 feet vertically above the parking lot. The outdoor air intake will be a minimum of 40 feet above the parking lot. To enhance the system beyond code requirements, additional filters and duct mounted CO sensors can be added to improve and monitor outdoor air intake quality but there are no performance based reasons for CCE to recommend this at this time.

HVAC‐2 uses the South shaft for its return and supply ductwork. The system is fully ducted, and the shaft is not used as an air plenum. New outside air ductwork would be installed from the roof level and connected to the existing return air ductwork within the South shaft. The ductwork along Federal Street would be removed. The louvers would remain and be blanked off with insulated sheet metal panels. A new outside air intake hood would be installed on the roof above the South shaft. Motorized dampers and an airflow measuring station would also be installed. This work involves one (1) roof penetration, removal and reconstruction of shaft walls, and reconfiguration of existing piping and ductwork within the vertical shaft. The proposed work for HVAC‐2 appears to be feasible based on the South shaft investigation.

HVAC‐3 duct configuration is similar to HVAC‐2, with the exception that it is located in the North shaft. A new outside air duct would be installed from the roof level to the existing return air ductwork within the North shaft. This configuration

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does not comply with P‐100 (2015) section 5.3.3.1, but it is the only feasible approach. Further discussion on this is provided in Work Item #2. The ductwork along Pearl Street would be removed. The louvers would remain and be insulated and blanked‐off. Motorized dampers and an airflow measuring station would be installed. This work involves one (1) roof penetration, removal and reconstruction of shaft walls and ceilings, and reconfiguration of existing piping and ductwork within the vertical shaft. The proposed work for HVAC‐3 appears to be feasible based on the North shaft investigation.

MAU‐1 is located in the basement custodial room (016) on the West side of the building. The ductwork along Market Street would be removed. The louvers would remain and be insulated and blanked‐off. There is a series of small closets adjacent the rotunda on the first and second floors that would be used as a vertical shaft for the outdoor air intake.

These closets are either empty or used for storage. At the time of this report, the use of these closets and whether these closets are common or tenant‐rented spaces was not fully confirmed. The use of these closets is a viable option for routing of ductwork, but verification of the existing use shall be determined during the design phase of this project. A new outdoor air intake hood would be installed on the roof above the new vertical shaft. A new outside air duct would be installed within the vertical shaft from the roof level to MAU‐1. Fire dampers would be installed to maintain existing fire‐rated barriers. This work involves one (1) roof penetration, reconfiguration of closets into a vertical shaft, and one

(1) wall penetration into the air handling room. Work Item #2 will incorporate further modifications to the MAU‐1 system.

P‐100 requires the outdoor air intake to be located a minimum distance away from certain objects (see table 6‐2). The chiller replacement job will utilize air cooled chillers, not impacting the distance requirements. All new intake locations shall comply with P‐100’s table 6‐2.

Architecture: To accommodate the installation of the new exhaust ductwork it will be necessary to create new wall penetrations. To install the ductwork in the shafts, new opening in the shaft walls will be required; these openings are to be kept to a minimum. This will require the cutting and removal of the existing wall construction, and, accordingly, the reinstallation of wall construction or installation of new access panels once the mechanical work has been completed. Also, existing floor and roof structure penetrations will be required to accommodate ductwork installation.

As this building is a Historic Facility, The existing wall materials will be replaced to match existing to the point of non‐ removal state. This will require specific effort to match existing materials at the location of removal and repainting of the entire wall to conceal any removal work performed. The materials required will be concrete masonry units, metal framing, gypsum board, plaster finish, and painting. During the design process it will be required of the design firm to conduct existing material analysis (core samples) to determine the specific materials required to match existing. As the existing intake and exhaust louvers at ground/basement level will no longer be required it is necessary to “close‐off” these louvers. It is recommended that the louvers remain in place and board insulation with painted plywood be installed on the inside of the louvers to make a weather tight seal. Other options are to remove the intake and exhaust louvers and install new window units to match existing in the exterior wall openings, or to fill in the openings with materials to match existing adjacent construction. The recommended option would be the less expensive method and the appearance of the building would be unchanged. As noted, Option B incorporates installation of exposed exterior ductwork on the exterior wall of the interior courtyard; as this is not a public way the A/E and GSA will work closely with

Table 6‐2 Minimum Separation Distances between Ventilation Air Intakes and Other Building Features:

Object Minimum Distance (feet)

Garage Entry, Loading Dock 25

Driveway, Street, or Public Way 10

Limited‐Access Highway 25

Cooling Tower or Evaporative Condensers 25

Exhaust Fans and Plumbing Vents 15

Kitchen Exhaust Air 25

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the ME SHPO to ensure that any exterior ductwork will have a minimal on the building’s Historic fabric. All associated drawings and specifications regarding all wall, ceiling, and roof penetrations along with exterior elevations will need to be prepared for GSA for SHPO review.

Work Item 2: Upgrade Air Handling Units and Distribution Existing HVAC‐1, HVAC‐2, and HVAC‐3 & HVAC‐4: HVAC‐1, ‐2, ‐3 & ‐4 are all Trane Modular Climate Changers, which is a discontinued model. Records show that HVAC‐1, ‐2, ‐3 & ‐4 are approximately 20 years old, exceeding their expected useful life of 15 years. All of the units appear to be in fair to poor condition. The units are configured with mixing boxes, filters, heating and cooling coils, humidifiers and supply fans and have 1” insulated walls. The units have humidification coils but these are no longer in use.

Work Item #2: Table 2.1

HVAC‐1, Model MCAA066, is located in the basement mechanical room (042) and is capable of supplying 31,700 cubic feet per minute (cfm) of air with a minimum outside airflow rate of 6,740 cfm. HVAC‐1 serves spaces on every floor of the building, primarily offices and conference rooms. HVAC‐1 utilizes Variable Air Volume (VAV) boxes with reheat coils to distribute the air to the spaces. The VAV boxes create several zones throughout the building by varying the supply airflow at constant temperature. A return fan (RF‐1), manufactured by Greenheck Model 44‐TCF‐1‐HBM‐T‐A250, and is used to pull return air to HVAC‐1. RF‐1 is approximately 20 years old and is approaching its expected useful life of 25 years. It is located in the basement mechanical room (042) and appears to be in fair condition.

HVAC‐2, Model MCAA017, is located in the basement mechanical room (042) and is capable of supplying 8,000 cfm of air with a minimum outside airflow rate of 2,840 cfm. HVAC‐2 serves the second floor district courtroom (258) with a constant volume air flow and varying supply temperature.

HVAC‐3, Model MCAA010, is located in the basement mechanical room (042) and is capable of supplying 4,500 cfm of air with a minimum outside airflow rate of 2,000 cfm. HVAC‐3 serves the third floor grand jury room (355) with a constant volume air flow and varying supply temperature.

HVAC‐4, Model MCAA017, is located in the third floor mechanical room (328) and is capable of supplying 7,200 cfm of air with a minimum outside airflow rate of 2,400 cfm. HVAC‐4 serves the second floor district courtroom (221) with a constant volume air flow and varying supply temperature.

Existing MAU‐1: MAU‐1 is also a Trane Modular Climate Changer. Records show that MAU‐1 is approximately 20 years old, exceeding its expected useful life of 15 years. MAU‐1, Model MCAA008, is located in the basement custodial room

(016) and is capable of supplying 3,000 cfm of outside air. There is no dedicated exhaust or return air ductwork system associated with MAU‐1. The unit appears to be in fair condition. It is configured with filters, heating and cooling coils, a

Existing Air Handling Units

Tag Min

OA

Max

OA

MAKE Model

HVAC‐1 6,740 31,700 Trane Modular Climate Changer

HVAC‐2 2,840 8,000 Trane Modular Climate Changer

HVAC‐3 2,000 4,500 Trane Modular Climate Changer

HVAC‐4 2,400 7,200 Trane Modular Climate Changer

MAU‐1 3,000 3,000 Trane Modular Climate Changer

RF‐1 ‐ 31,700 Greenheck 44‐TCF‐1‐HBM‐T‐A250

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humidifier and a supply fan and has 1” insulated walls. The unit has a humidification coil that is no longer in use. MAU‐1 provides ventilation air to storage and custodial spaces in the basement, first floor offices on the Northwest side of the building, and the judges’ chambers on the first and second floors on the South side of the building.

In the basement, ventilation air is provided to the spaces through wall mounted grilles near the ceiling. In the first floor, ventilation air is provided to the spaces from overhead ceiling diffusers. In the second floor judges’ chambers, the ventilation air is provided to the spaces through floor mounted supply grilles. Fan coil units are located directly above the floor mounted supply grilles. The ventilation air effectiveness appears to be inadequate due to the absence of a return and exhaust air system.

Existing Bathroom Exhaust Fans (EF): There are five (5) rooftop exhaust fans servings the bathrooms and locker rooms within the building. EF‐2 (1,230 cfm) serves the North Bathrooms, EF‐3 (1,850 cfm) serves the East Bathrooms, EF‐4 (750 cfm) serves the first floor Cell Bathrooms, EF‐5 (780 cfm) serves the South Bathrooms, and EF‐6 (265 cfm) serves the West Bathrooms.

Existing Air Compressor and Humidification System: There is an existing Powerex Model 0LD15‐6A2 air compressor, installed in 1995, located in the basement mechanical room (042). The unit was dedicated for the humidification system that is no longer in use due to operational and maintenance issues. The design intention was to use an air compressor and water to atomize the water and introduce it into the air handling system. Each air handling unit has a section between the heating and cooling coils where the humidification coil is located.

P‐100 Ch. 5 (Mechanical Engineering) states that “for general occupancy, higher levels of humidity control performance are not required or encouraged.” However, P‐100 Ch. 8. (Design Standards for US Court Facilities) states that the HVAC system shall maintain 45‐50% relative humidity for summer conditions and 25‐35% relative humidity for winter conditions. Indoor relative humidity data was collected from within the building using four (4) humidity loggers that were setup from September 2015 through January 2016. Logger #4 was also relocated to a courtroom for a duration of four (4) days. The charts below display the relative humidity in the building. Refer to Work Item #2 sketches for humidity logger locations.

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Date

Data Logger Number 1 Second Floor Reception 242

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Date

Data Logger Number 2 Second Floor Library 235

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Date

Data Logger Number 3 Second Floor Reception 231

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The humidity loggers show relative humidity levels dropping below 25% (P‐100’s Ch. 8 low winter limit) during January.

The majority of the time, the relative humidity trend line is within P‐100 ranges.

There are two (2) different types of humidification systems: adiabatic and isothermal. An adiabatic system uses pressure to atomize water (convert water into fine particles) and introduce it into the air handling unit. The existing compressed

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Date

Data Logger Number 4 Second Floor Corridor 225

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Date

Data Logger Number 4 Second Floor District Courtroom 221

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air system is an adiabatic system. An isothermal system uses an external heat source to convert water into steam, which is then introduced into the air handling system. Gas‐fired steam generation, electric steam generation, and district steam are all examples of an isothermal system.

An adiabatic humidification system typically requires 6 to 8 feet of straight duct for the absorption to occur. Currently, the longest length after the dispersion is 15‐Inches, which is significantly less than the recommended 6 to 8 feet.

Additionally, it is recommended to use deionized water or reverse osmosis for this type of system. It is believed that untreated tap water was used for the humidification system at Gignoux. It is possible that problems, such as dusting or clogging, occurred due to the short absorption distance and lack of treated water. A compressed air humidification system at the Gignoux Courthouse is not recommended based on the two issues previously noted.

An isothermal system was evaluated for the Gignoux Courthouse as part of this project. These types of systems require 2 to 3 feet of absorption distance, which can be reduced by using manufactured dispersion devices. As district steam is not available, a gas‐fired steam generator and electric steam generator were considered. A gas‐fired steam generator requires a significant amount of maintenance and is difficult to use with varying airflows. An electric humidification system requires the least amount of maintenance and is able to modulate with fluctuating airflows. Armstrong International HumidiClean Series HC‐6000 (see Appendix E) were used as the basis of the study. The electrical service available at the building, 208 Volt/ 3‐Phase, limits the steam output capacity of one unit to a maximum of 135 lbs./hr.

An energy model was compiled to determine the estimated humidification load for each system. The results are listed in Table 2.2 below. For HVAC‐1, four (4) electric humidification units, installed in series, would be required to match the modeled results. MAU‐2 would require two (2) electric humidification units, installed in series. The remaining three (3) AHUs would require one (1) electric humidification unit. The estimated installation cost of nine (9) HumidiClean units, based on the modeled results, and the estimated yearly operating cost (using the Trace energy model, Appendix F) are listed in Table 2.2.

Work Item #2: Table 2.2

Lastly, the building is currently dealing with moisture and odor issues, which is being explored in an ongoing study separate from this PDS. There are no known issues or complaints resulting from low relative humidity. Additionally, P‐ 100 Ch. 5 mentions woodwork vulnerability as a potential driver for a humidification system. Colby Company does not

Humidification Coils Existing

Output Energy Model

Results Estimated # of Units Tag Serves

(LB/HR) (LB/HR)

HC‐1 HVAC‐1 216 546 4

HC‐2 HVAC‐2 90 144 1

HC‐3 HVAC‐3 66 78 1

HC‐4 HVAC‐4 78 134 1

HC‐5 MAU‐1 96 354 2

Notes: 1. Installation cost includes electrical and mechanical scope

2. Maximum capacity of a single electric humidification unit is 135 lb/hr

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believe the woodwork at Gignoux is particularly sensitive to low relative humidity levels. Based on the evaluation of the existing humidification system, potential replacement options, and existing moisture and odor issues, it is not recommended to have a humidification system at the Gignoux Courthouse. Colby Company recommends treating the building as “general occupancy” and complying with P‐100 Ch. 5 standards.

Work Item 2: On Friday August 25, 2015 and Friday September 11, 2015, Colby Company Engineering conducted a Load Survey for each floor of the Gignoux Courthouse. The As‐Built Drawings do not accurately depict all of the room configurations and usages. Several rooms throughout the building have changed both layouts and occupancy usage. An energy model, using Trane Trace 700, was compiled to determine the airflow requirements and heating and cooling loads. (Refer to Appendix F for calculations and energy model results and Appendix D for sketches). The following table compares the existing airflows to the calculated airflows:

Work Item #2: Table 2.3

HVAC‐1, ‐2, ‐3 & ‐4: Based on the age and condition of the HVAC units, it is recommended to replace the units in‐kind with Trane Modular Climate Changers model CSAA. Refer to Appendix E for cutsheets. The existing air handlers will be removed and the replacement units will be installed in the same locations. Modifications will be made to the ductwork, as discussed in Work Item 1, in order to comply with P‐100. The new units will have 2” of injected foam insulation (R‐13) with better deflection (deformation of the external surface of the casing) and a tighter leakage rate. Factory mounted Variable Frequency Drives (VFDs) will be incorporated to reduce energy usage. The system will be required to be tested, balanced, and recommissioned.

RF‐1: Based on the expected useful life of the existing RF‐1, it is recommended to replace the return fan. Manufacturer’s recommendation is to replace the unit with a Greenheck Model QEI due to lower operating horsepower, less noise, and lower equipment cost. Refer to Appendix E for the cutsheet. The new fan will be VFD rated and shall account for additional static pressure due to the additional intake ductwork.

MAU‐1: Based on the age and condition of the MAU‐1, it is recommended to replace the unit in‐kind with a Trane Modular Climate Changers model CSAA. Refer to Appendix E for the cutsheet. The existing MAU‐1 will be removed and the replacement MAU‐1 will be installed in the same location. The new unit will have 2” of injected foam insulation (R‐

13) with better deflection and a tighter leakage rate. A factory mounted Variable Frequency Drive (VFD) will be incorporated to reduce energy usage. The system will be required to be tested, balanced, and recommissioned.

Minimum Outdoor Airflow Analysis: Per P‐100 Ch.8 ‐ 20 CFM/Person

EQUIP

Room Area (ft2)

Height (ft)

Volume (ft3)

#ppla cfm per personb

Min

OA

(CFM)c

Existing

OA

CFM

Max CFMc

Existing Max

CFM

Serves

HVAC‐1 27,155 ‐ ‐ 301 20 6,499 6,740 22,519 31,700 Offices

HVAC‐2 2,780 23 63,940 195 20 3,894 2,840 6,057 8,000 district courtroom 258

HVAC‐3 1,447 11 15,917 101 20 2,027 2,000 3,583 4,500 grand jury suite 355

HVAC‐4 2,436 25 60,900 171 20 3,412 2,400 5,585 7,200 district courtroom 221

MAU‐1 21,010 ‐ ‐ 136 20 2,839 3,000 2,839 3,000 Offices

Notes a Based on ASHRAE Standard 62.1‐2019 Ventilation for Acceptable Indoor Air Quality b Based on P‐100 Chapter 8, Design Standard for U.S. Court Facilities c Based on Trace 700 Energy Model

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Modifications will be made to the outdoor air intake ductwork, as discussed in Work Item 1, in order to comply with P‐

100. To improve the ventilation effectiveness for MAU‐1, ductwork will be installed and routed to an existing shaft space on the North side of the building adjacent the rotunda. On the second floor, the ventilation air in the office spaces must transfer into the hallway to improve ventilation effectiveness (see MSK‐202). The air in the hallway will be ducted to the rooftop ERV. Transfer grilles shall not be installed in the doors, as they are all historic. The majority of the doors have transom windows above (see photo in Appendix A), some fixed and some operable. The design shall utilize the door undercuts and windows when feasible, and new transfer grilles and acoustic lined ductwork if the undercuts/windows are not sufficient. The goal is to minimize the amount of transfer grilles. On the third floor, ductwork will be installed from the shaft to the roof level, where it will exhaust through an energy recovery ventilator. Refer to the Work Item #2 sketch for this work.

An alternative option was evaluated to install three (3) rooftop exhaust fans to serve spaces ventilated by MAU‐1, which would eliminate new ductwork on the second floor. Three (3) exhaust fans would be required based on the locations of the spaces served by MAU‐1. However, this would eliminate the energy recovery ventilator, require additional floor penetrations, require additional ceiling return grilles, and be challenging to balance the system.

VFDs: VFDs are beneficial during final balancing and allow for a soft motor start resulting in less wear and tear on the unit. HVAC‐1 is a VAV system and MAU‐1 is proposed to be a VAV system. For MAU‐1 and HVAC‐1, VFDs will allow the fan speed to modulate based on ventilation air requirements.

Special Area HVAC Systems: P‐100 states that special areas, such as entrance lobbies and vestibules, must have dedicated HVAC systems. Fan coil units serve the rotunda entrance as well as the rear entrance on Newbury Street.

These units should be replaced with new fan coil units. The capacities of the new units should be increased as needed to satisfy the space they serve. A new air curtain should be installed in the vestibule on Newbury Street. Ventilation air for these spaces are satisfied by the frequent air changes due to the use of the exit and entrance door.

General Room Improvements: The basement Marshall Office space, converted from storage and custodial space, should be modified, tested and balanced to provide adequate ventilation air and satisfy thermal comfort. During the design phase, heating and cooling loads will determine whether the existing fan coil units are sized appropriately.

The cell control room (160) on the first floor has a significant amount of electrical equipment. HVAC‐1 serves the room and provides ventilation air through a dedicated VAV box, which is supposed to satisfy the cooling and heating loads.

The user of the room has a floor fan to help with thermal comfort. It is recommended to install a fan coil unit in this room to adequately cool and heat the space.

Existing Air Compressor and Humidification System: The existing air compressor, humidification system, and all associated components shall be removed. For the potential future installation of a humidification system, the new air handlers should be equipped with a blank section between the heating and cooling coils, ensuring that is long enough to accommodate an electric humidification system. Refer to the humidification discussion in WI #2 for more information.

Energy Recovery Ventilators: P‐100 states that the building’s HVAC Energy Performance shall comply with ASHRAE 90.1 2010 (Energy Standard for Buildings Except Low‐Rise Residential Buildings). ASHRAE 90.1 Section 6.5.6 lists requirements for when Energy Recovery Ventilators (ERVs) are to be installed. ASHRAE 90.1 2010 requires ERVs based on the percentage of outdoor air required, the systems design supply airflow rate, and the building’s climate zone. One exception to this requirement is when a system is expected to operate less than 20 hours per week at the outdoor air percentage listed in ASHRAE 90.1‐2010.

The Gignoux Courthouse estimates that the courtrooms on the second floor are occupied 20 hours per week on average and the courtroom on the third floor is occupied 25 hours per week on average. The Courthouse reported that the courtrooms are rarely at full capacity, typically not exceeding 25% of the total capacity. Based on this information, ERVs

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serving HVAC‐2, HVAC‐3, and HVAC‐4 are not required per ASHRAE 90.1‐2010. Additionally, HVAC‐1 has a design outdoor airflow rate of 29% of the design supply airflow rate, which is less than the ASHRAE 90.1‐2010 minimum threshold of 30% that requires an ERV. MAU‐1 supplies 100% outdoor air, so an ERV is required to serve this unit per

ASHRAE 90.1‐2010.

Work Item #2: Table 2.4

Results show that…