UFC 3-410-01 HVAC.pdf

UFC 3-410-01

1 July 2013

Change 8, 21 July 2021

UNIFIED FACILITIES CRITERIA (UFC)

APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED

HEATING, VENTILATING, AND

AIR CONDITIONING SYSTEMS

Change 8, 21 July 2021

UNIFIED FACILITIES CRITERIA (UFC)

HEATING, VENTILATING, AND AIR CONDITIONING SYSTEMS

Any copyrighted material included in this UFC is identified at its point of use.

Use of the copyrighted material apart from this UFC must have the permission of the copyright holder.

U.S. ARMY CORPS OF ENGINEERS

NAVAL FACILITIES ENGINEERING SYSTEMS COMMAND (Preparing Activity)

AIR FORCE CIVIL ENGINEER CENTER

Record of Changes (changes are indicated by \1\ ... /1/)

Change No. Date Location 1 October 2014 Numerous clarifications, corrections, additions and deletions throughout the document in response to Criteria Change Requests (CCRs) and Tri-Service reviews; the addition of Appendices E, F and G.

2 October 2015 Changes to Chapters 3, 4, 5 and Appendix A in response to CCRs and Tri-Service reviews.

3 January 2017 Criteria Change Request to address variable refrigerant flow (VRF) systems.

4 November

Changes to Chapters 3 and 4 and Appendices A and B in response to CCRs and Tri-Service reviews.

5 November

Added Environmental Severity Classification and humidity design requirements and updated corrosion prevention requirements in 1-3.1, 3-6.11, 3-6.11.1, 4- 2.4.5, 5-2.25, B-12 and B-13.

6 March 2020 Changes to Chapter 3 for VRF requirements and Chapter 4 for referencing IMC-2018. Numerous clarifications, corrections, additions and deletions throughout the document in response to Criteria Change Requests (CCRs) and Tri-Service reviews.

7 February

Change in 3-6.17.3 Design Requirements for VRF Systems paragraph no. 3, and 3-7.6 Electric Resistance Heating.

8 July 2021 Criteria Change Requests to address variable refrigerant flow (VRF) systems.

Change 8, 21 July 2021

This UFC supersedes UFC 3-400-10N, dated July 2006; UFC 3-410-01FA, dated 15 May 2003; MIL-HDBK-1190, Chapter 10, dated 1 September 1987; and TI 800-01, Chapter 13, dated 20 July 1998.

Change 8, 21 July 2021

FOREWORD

The Unified Facilities Criteria (UFC) system is prescribed by MIL-STD 3007 and provides planning, design, construction, sustainment, restoration, and modernization criteria, and applies to the Military Departments, the Defense Agencies, and the DoD Field Activities in accordance with USD (AT&L) Memorandum dated 29 May 2002. UFC will be used for all DoD projects and work for other customers where appropriate. All construction outside of the United States is also governed by Status of Forces Agreements (SOFA), Host Nation Funded Construction Agreements (HNFA), and in some instances, Bilateral Infrastructure Agreements (BIA.)

Therefore, the acquisition team must ensure compliance with the most stringent of the UFC, the SOFA, the HNFA, and the BIA, as applicable.

UFC are living documents and will be periodically reviewed, updated, and made available to users as part of the Services’ responsibility for providing technical criteria for military construction. Headquarters, U.S. Army Corps of Engineers (HQUSACE), Naval Facilities Engineering Systems Command (NAVFAC), and the Air Force Civil Engineer Center (AFCEC) are responsible for administration of the UFC system. Defense agencies should contact the preparing service for document interpretation and improvements. Technical content of UFC is the responsibility of the cognizant DoD working group. Recommended changes with supporting rationale should be sent to the respective service proponent office by the following electronic form: Criteria Change Request. The form is also accessible from the Internet sites listed below.

UFC are effective upon issuance and are distributed only in electronic media from the following source:

• Whole Building Design Guide web site http://dod.wbdg.org/.

Hard copies of UFC printed from electronic media should be checked against the current electronic version prior to use to ensure that they are current.

AUTHORIZED BY:

JAMES C. DALTON, P.E. JOSEPH E. GOTT, P.E.

Chief, Engineering and Construction Chief Engineer U.S. Army Corps of Engineers Naval Facilities Engineering Command

JOE SCIABICA, SES MICHAEL McANDREW Director Director, Facilities Investment and Management

Air Force Civil Engineer Center Office of the Deputy Under Secretary of Defense (Installations and Environment)

Change 8, 21 July 2021

UNIFIED FACILITIES CRITERIA (UFC)

NEW SUMMARY SHEET

Document: UFC 3-410-01, Heating, Ventilating, and Air Conditioning Systems

Superseding: This UFC supersedes UFC 3-400-10N, Mechanical Engineering; UFC 3- 410-01FA, Heating, Ventilating, and Air Conditioning; MIL-HDBK-1190, Facility Planning and Design, Chapter 10; and TI 800-01, Design Criteria, Chapter 13.

Description: This UFC provides requirements for the design of facility heating, ventilating, and Air Conditioning systems. It incorporates the provisions of the International Code Council’s International Mechanical Code (IMC) and ASHRAE design guidance to the greatest extent possible. This UFC is to be applied in conjunction with the core mechanical UFC 3-401-01.

Reasons for Document:

• To unify Department of Defense facility HVAC criteria and create more consistency in DoD designs.

• To incorporate and modify the provisions of the IMC to meet DoD needs.

• To update existing criteria to reflect new and revised industry standards.

Impact:

• Standardized guidance for facility HVAC design among the Services.

• Provides more detail on documentation requirements for design analysis and drawing requirements.

• Incorporates lessons learned from issues which occurred in previous construction contracts.

Unification Issues

• The Navy uses UFC 3-430-08N, Central Heating Plants for design of central heating plants while the Army and Air Force use 3-430-02FA, Central Steam Boiler Plants. There is an ongoing Army project to update and unify these documents.

• ASHRAE's BACnet® protocol is the preferred control system architecture for Navy & Marine Corp facilities. LonWorks® protocol is the preferred control system architecture for Army facilities. The Army uses UFC 3-410-02 for LonWorks® protocol control systems design.

Change 8, 21 July 2021 i

TABLE OF CONTENTS

CHAPTER 1 INTRODUCTION

1-1 PURPOSE AND SCOPE

1-2 APPLICABILITY

1-3 GENERAL BUILDING REQUIREMENTS

1-3.1 \5\ Environmental Severity and Humid Locations

1-4 \6\ CYBERSECURITY

1-5 REFERENCES

1-6 BEST PRACTICES

1-7 GLOSSARY

1-8 \8\ OPEN CONTROL SYSTEM REQUIREMENTS

1-9 EPA HFC-REFRIGERANT REGULATIONS

CHAPTER 2 MECHANICAL CONSENSUS STANDARDS

2-1 PRIMARY VOLUNTARY CONSENSUS STANDARD REFERENCE

2-1.1 International Mechanical Code© Copyright

2-1.2 IMC Additions, Deletions, and Revisions

CHAPTER 3 GENERAL DESIGN REQUIREMENTS

3-1 \1\ HVAC /1/ SYSTEM SELECTION \1\ AND LIFE CYCLE COST

ANALYSIS CONSIDERATIONS

3-2 \6\ [FOR NAVY PROJECTS ONLY] VENTILATION AIR

3-2.1 DOAS Associated with Light-Duty Equipment

3-2.2 DOAS Associated with Medium-Duty Equipment

3-2.3 DOAS Associated with Light-Duty or Medium-Duty Equipment

3-2.4 Additional Requirements

3-3 \6\ [FOR AIR FORCE PROJECTS ONLY] VENTILATION AIR

3-3.1 DOAS Requirements

3-3.2 General Ventilation Requirements

3-4 \4\ \2\ [FOR ARMY PROJECTS ONLY] VENTILATION AIR AND USE OF

DOAS

3-5 HEATING AND COOLING LOAD CALCULATIONS

3-5.1 Load Calculations

3-5.2 Outdoor Design Conditions

3-5.3 Indoor Design Conditions

Change 8, 21 July 2021 ii

3-6 SPECIFIC FACILITY-TYPE HVAC REQUIREMENTS

3-6.1 Facility Air Conditioning Eligibility

3-6.2 Natural or Mechanical Ventilation Requirements

3-6.3 Nonpermanent Construction

3-6.4 Intermittent Occupancy Facilities

3-6.5 Vestibules

3-6.6 Closets and Storage in Air Conditioned Facilities

3-6.7 Aircraft Maintenance Shops

3-6.8 Data Processing Centers and \1\ Server Rooms. /1/

3-6.9 Health Care Facilities

3-6.10 Laboratories

3-6.11 Fitness Centers

3-6.12 General Purpose Aircraft Hangars

3-6.13 Aircraft Fire and Rescue and Fire Station

3-6.14 \6\ Telecommunications Rooms

3-6.15 Laundries and Dry Cleaners

3-6.16 Dining Facilities

3-6.17 Variable Refrigerant Flow (VRF) Systems

3-7 OTHER HVAC DESIGN CONSIDERATIONS

3-7.1 Latent Load Considerations

3-7.2 Reheat

3-7.3 Economizer

3-7.4 Redundant Systems

3-7.5 Humidification

3-7.6 Electric Resistance Heating

3-7.7 Steam Systems

3-7.8 Fan Coil Applications for Ventilation Air

3-7.9 Ground Coupled Heat Pumps

3-7.10 Variable Air Volume (VAV) Cooling

3-7.11 \1\ Corrosion

3-7.12 Sound and Vibration Control

3-7.13 Radon

Change 8, 21 July 2021 iii

3-7.14 HVAC System Testing & Balancing

3-7.15 Commissioning Requirements

CHAPTER 4 SUPPLEMENTAL IMC TECHNICAL CRITERIA

4-1 GENERAL SUBSTITUTIONS

4-2 IMC SUPPLEMENTARY PARAGRAPHS

4-2.1 IMC CHAPTER 1 “SCOPE AND ADMINISTRATION” SUPPLEMENTS.

4-2.2 IMC CHAPTER 2 “DEFINITIONS” SUPPLEMENTS

4-2.3 IMC CHAPTER 3 “GENERAL REGULATIONS” SUPPLEMENTS

4-2.4 IMC CHAPTER 4 “VENTILATION” SUPPLEMENTS

4-2.5 IMC CHAPTER 5 “EXHAUST SYSTEMS” SUPPLEMENTS

4-2.6 IMC CHAPTER 6 “DUCT SYSTEMS” SUPPLEMENTS

4-2.7 IMC CHAPTER 8 “CHIMNEYS & VENTS” SUPPLEMENTS

4-2.8 IMC CHAPTER 9 “SPECIFIC APPLIANCES, FIREPLACES AND

SOLID FUEL-BURNING EQUIPMENT” SUPPLEMENTS

4-2.9 IMC CHAPTER 10 “BOILERS, WATER HEATERS AND PRESSURE

VESSELS” SUPPLEMENTS

4-2.10 IMC CHAPTER 11 “REFRIGERATION” SUPPLEMENTS

4-2.11 IMC CHAPTER 12 “HYDRONIC PIPING” SUPPLEMENTS

4-2.12 IMC CHAPTER 13 “FUEL OIL PIPING AND STORAGE”

SUPPLEMENTS

4-2.13 IMC CHAPTER 14 “SOLAR SYSTEMS” SUPPLEMENTS

CHAPTER 5 DESIGN ANALYSIS AND DRAWING REQUIREMENTS

5-1 DESIGN ANALYSIS

5-1.1 Basis of Design Narrative Requirements

5-1.2 Calculations and Analysis Requirements

5-2 FINAL DRAWING REQUIREMENTS

5-2.1 Site Work

5-2.2 Floor Plans

5-2.3 Enlarged Plans

5-2.4 Mechanical Room Plans

5-2.5 Schematic Diagrams

5-2.6 Design Conditions

Change 8, 21 July 2021 iv

5-2.7 Equipment Schedules

5-2.8 Control Valves Schedule

5-2.9 Metric Valve Coefficient

5-2.10 Outdoor Air Schedule

5-2.11 Vibration Isolator Schedule

5-2.12 Fouling Factors

5-2.13 Details

5-2.14 Access Panels

5-2.15 Sequence of Operations

5-2.16 Control Diagrams

5-2.17 Roof Fans

5-2.18 Equipment Supports

5-2.19 Drain Lines

5-2.20 Balance Dampers

5-2.21 Ductwork Testing

5-2.22 Duct Construction Classifications

5-2.23 \1\ Make-up Water. /1/

5-2.24 Flow and Slope Arrows

5-2.25 Guides for Piping

5-2.26 Pipe Anchors

5-2.27 Pressure Gauges

5-2.28 Air Vents

5-2.29 Balance Valves

5-2.30 Kitchen Hood Diagram

APPENDIX A REFERENCES

APPENDIX B BEST PRACTICES

B-1 OUTSIDE AIR INTAKES

B-2 INDEPENDENT VENTILATION SYSTEMS

B-3 PURGE MODE

B-4 FILTRATION

B-5 COMFORT VENTILATION

B-6 FAN COIL UNITS

Change 8, 21 July 2021 v

B-7 \1\ DEDICATED OUTSIDE AIR SYSTEM (DOAS). /1/

B-8 INFRARED HEATING

B-9 RELIABILITY

B-10 PHOTOCOPIERS & LASER PRINTERS

B-11 VRF SYSTEMS

B-12 \5\ CAPACITY OF EQUIPMENT

B-13 \5\ LOCATION OF EXHAUST REGISTERS FOR MOISTURE

REMOVAL

APPENDIX C GLOSSARY

APPENDIX D MINIMUM CONTROL POINTS LIST

APPENDIX E – HVAC SYSTEM SELECTION FLOW CHART

APPENDIX F – 90% ENERGY-EFFICIENT HVAC SOLUTIONS (FOR ARMY

PROJECTS ONLY)

APPENDIX G - EVALUATION OF DISTRICT AND ISLANDED/DECENTRALIZED

UTILITY OPTIONS WITH LIFE-CYCLE COST ANALYSIS GUIDANCE

(FOR ARMY PROJECTS ONLY)

TABLES

Table 6-2 Ductwork Construction and Leakage Testing Table...…..……………… Table D-1 DDC Minimum Points List………………………………………………………74

Change 8, 21 July 2021

CHAPTER 1 INTRODUCTION

1-1 PURPOSE AND SCOPE.

This UFC provides requirements and guidance in the design of heating, ventilating, and air-conditioning (HVAC) systems, together with the criteria for selecting HVAC materials and equipment.

1-2 APPLICABILITY.

This UFC is applicable to all service elements and contractors involved in the planning, design and construction of DoD facilities worldwide. Where conflicts in requirements appear between sections of any mechanical UFC or applicable codes or laws, the most restrictive requirement will govern.

1-3 GENERAL BUILDING REQUIREMENTS.

\6\ Comply with UFC 1-200-01, DoD Building Code (General Building Requirements).

UFC 1-200-01 provides applicability of model building codes and government unique criteria for typical design disciplines and building systems, as well as for accessibility, antiterrorism, physical security, cybersecurity, high performance and sustainability requirements, and safety. Use this UFC in addition to UFC 1-200-01 and the UFCs and government criteria referenced therein. /6/

1-3.1 \5\ Environmental Severity and Humid Locations.

In corrosive and humid environments, provide design detailing, and use materials, systems, components, and coatings that are durable and minimize the need for preventative and corrective maintenance over the expected service life of the component or system. UFC 1-200-01, section titled “Corrosion Prone Locations” identifies corrosive environments and humid locations requiring special attention. UFC 1-200-01, section titled “Requirements for Corrosion Prone Locations” provides examples of necessary actions. To determine Environmental Severity Classifications (ESC) for specific project locations refer to UFC 1-200-01 Appendix titled “Environmental Severity Classifications (ESC) for DoD Locations”. /5/

1-4 \6\ CYBERSECURITY.

All control systems (including systems separate from a utility monitoring and control system) must be planned, designed, acquired, executed, and maintained in accordance with UFC 4-010-06 and as required by individual Service Implementation Policy.

Cybersecurity is implemented to mitigate vulnerabilities to all DoD real property facility-related control systems to a level that is acceptable to the System Owner and Authorizing Official. UFC 4-010-06 provides requirements for integrating cybersecurity into the design and construction of control systems. /6/

Change 8, 21 July 2021

1-5 REFERENCES.

Appendix A contains a list of references used in this document. The publication date of the code or standard is not included in this document. In general, the latest available issuance of the reference is used.

1-6 BEST PRACTICES.

Appendix B contains information that is not requirements but is considered best practices based on experience and lessons learned.

Change 8, 21 July 2021

1-7 GLOSSARY.

Appendix C contains acronyms, abbreviations, and terms.

1-8 \8\ OPEN CONTROL SYSTEM REQUIREMENTS.

10 USC 2867 requires the adoption of a “Department-wide, Open Protocol, Energy Monitoring and Utility Control System Specification” for use in military construction and military family housing activities. Public law (10 USC 2867) states: “The Secretary of Defense shall adopt an open protocol energy monitoring and utility control system specification for use throughout the Department of Defense in connection with a military construction project, ...” It continues: “The energy monitoring and utility control system specification ... shall cover: (A) ... (B) Indoor environments, including temperature and humidity levels. (C) Heating, ventilation, and cooling components. ...” DoD has published the following control system specifications to meet this requirement:

1. UFGS 25 10 10 Utility Monitoring and Control System (UMCS) Front End and Integration

2. UFGS 23 09 00 Instrumentation and Control for HVAC

3. UFGS 23 09 23.01 LonWorks Digital Control for HVAC and Other Building Control Systems

4. UFGS 23 09 23.02 BACnet Digital Control for HVAC and Other Building Control Systems

All HVAC control systems must meet the requirements of UFGS 23 09 00 and either UFGS 23 09 23.01 or UFGS 23 09 23.02 These specifications require the installation of non-proprietary control networks down to the level of each individual device in the system.

1-9 EPA HFC-REFRIGERANT REGULATIONS.

Beginning 1-Jan-2019, the EPA implemented new rules to regulate HFC refrigerant systems including those used for comfort cooling. This regulation includes R-410A, a common HFC refrigerant used in DX systems. The new rules lowered the threshold leak rate to 10% loss annually. Systems exceeding this rate must be repaired within 30-days or else face mandatory system shutdown, costly retrofits, or replacement. (The Services estimate a current annual refrigerant leak rate of 25%.) /8/

Change 8, 21 July 2021

This Page Intentionally Left Blank

Change 8, 21 July 2021

CHAPTER 2 MECHANICAL CONSENSUS STANDARDS

2-1 PRIMARY VOLUNTARY CONSENSUS STANDARD REFERENCE.

The DoD uses the International Code Council™ International Mechanical Code© as the primary voluntary consensus standard for DoD facility HVAC systems. The scope of the IMC is stated as:

“This code must regulate the design, installation, maintenance, alteration and inspection of mechanical systems that are permanently installed and utilized to provide control of environmental conditions and related processes within buildings.”

2-1.1 International Mechanical Code© Copyright.

The International Mechanical Code© is copyrighted by International Code Council, Inc., Falls Church, Virginia, U.S.A. Without advance written permission from ICC or its duly authorized agent, no portion of the IMC may be reproduced, distributed, or transmitted in any form or by any means, including, without limitation, electronic, optical, or mechanical means (by way of example and not limitation, photocopying, or recording by or in an information storage and retrieval system). For information on permission to copy IMC material exceeding fair use, please contact the International Code Council, Inc.

2-1.2 IMC Additions, Deletions, and Revisions.

The additions, deletions, and revisions to the IMC sections listed in Chapter 4 “Supplemental Technical Criteria” of this document preserve the appropriate supplemental technical criteria for use in current and future designs of DoD facilities.

When and if these supplemental technical criteria are adopted into the IMC, they will be removed from this document. When interpreting the IMC, the advisory provisions must be considered mandatory; interpret the word “should” as “must.” The format of Chapter 4, including English and metric unit references, does not follow the UFC format, but instead follows the format established in the IMC, to the extent possible.

Change 8, 21 July 2021

This Page Intentionally Left Blank

Change 8, 21 July 2021

CHAPTER 3 GENERAL DESIGN REQUIREMENTS

3-1 \1\ HVAC /1/ SYSTEM SELECTION \1\ AND LIFE CYCLE COST

ANALYSIS CONSIDERATIONS.

\6\ The designer must develop three energy efficient solutions for each individual energy system and prepare a LCCA to determine the heating and cooling systems, fuel sources and major system components. Designers should follow Appendix E - HVAC Systems Selection Flow Chart for this selection process. The analysis must conform to the life cycle cost and energy criteria specified in UFC 1-200-02 /6/. For Army projects only:

Centralized versus De-centralized Plants - De-centralized plants may be a more cost effective alternative for a new or replacement project. The designer must follow the "Evaluation of District and Islanded/Decentralized Utility Options with Life-Cycle Cost Analysis Guidance" in Appendix G to determine which alternative is most life cycle cost effective. /1/

3-2 \6\ [FOR NAVY PROJECTS ONLY] VENTILATION AIR.

\4\ These requirements apply to Navy projects. Final determination of equipment’s dehumidification capabilities is subject to approval by the Navy based on submitted equipment selections, control sequences, and psychrometrics. /6/

A Dedicated Outdoor Air System (DOAS) is the only allowed method for providing dehumidification of ventilation air (outside air) when replacing an existing DOAS delivering any quantity of ventilation air or when the sum of all ventilation air into facility is greater than 750 cfm (354 lps) and either of the following conditions apply:

• Design includes any direct-expansion or chilled water equipment such as heat pumps, packaged terminal air conditioners, split systems, and fan coil units delivering any quantity of outside air with limited dehumidification capability referred to below as light-duty equipment

• Design includes any direct-expansion equipment delivering any quantity of outside air with cycling refrigeration circuit(s) not manufactured and controlled for continuous dehumidification referred to below as medium-duty equipment

3-2.1 DOAS Associated with Light-Duty Equipment.

DOAS’s associated with light-duty equipment must be selected, designed, and controlled as follows:

• Cooling coil must be selected to meet outside air sensible and latent loads plus space latent load

• Cooling coil must be selected and controlled to maintain a continuous coil leaving air temperature no greater than 55.0 °F for applications requiring

Change 8, 21 July 2021 space conditions of 78.0 °F dry-bulb / 57.9 °F dewpoint / 50-percent relative humidity

• Cooling coil must be selected and controlled to maintain a continuous coil leaving air temperature suitable for applications requiring space conditions more stringent than 78.0 °F dry-bulb / 57.9 °F dewpoint / 50-percent relative humidity

• Reheat coil must be selected and controlled to maintain a unit discharge air temperature equivalent to the facility average design temperatures for comfort cooling and comfort heating

(73.0 °F for 78.0 °F comfort cooling / 68.0 °F comfort heating)

• DOAS must not be subject to intermediate season (no-heat / no-cool) shutdown

• DOAS must distribute airflow directly to zones without passing through light-duty equipment

• DOAS air inlets and outlets must deliver airflow quantities equal to or greater than 50 cfm (24 lps) through each device to allow for proper system balancing

3-2.2 DOAS Associated with Medium-Duty Equipment.

DOAS’s associated with medium-duty equipment must be selected, designed, and controlled as follows:

• Cooling coil must be selected to meet outside air sensible and latent loads, but not space loads

• Cooling coil must be selected and controlled to maintain a continuous coil leaving air temperature no greater than 58.0 °F for applications requiring space conditions of 78.0 °F dry-bulb / 57.9 °F dewpoint / 50-percent relative humidity

• Cooling coil must be selected and controlled to maintain a continuous coil leaving air temperature suitable for applications requiring space conditions more stringent than 78.0 °F dry-bulb / 57.9 °F dewpoint / 50-percent relative humidity

• Reheat coil must be designed and controlled to maintain a unit discharge air temperature equivalent to DOAS’s coil leaving air setpoint temperature plus 5.0 °F to maintain discharge ductwork relative humidity less than 90-percent to help prevent ductwork microbial growth

• DOAS must distribute airflow directly into inlet of associated equipment and must not distribute airflow directly into zones

3-2.3 DOAS Associated with Light-Duty or Medium-Duty Equipment.

Change 8, 21 July 2021

DOAS’s associated with light-duty or medium-duty equipment, in addition to other requirements, must be selected, designed, and controlled as follows:

• DOAS must be provided with energy recovery devices in accordance with

ASHRAE 90.1

• Energy recovery devices must be controlled to never increase energy (enthalpy) of outside air when energy of outside air upstream of energy recovery device is greater than energy of outside air immediately downstream of DOAS’s cooling coil

• Energy recovery devices must be controlled to never decrease dry-bulb temperature of outside air when dry-bulb temperature of outside air upstream of energy recovery device is less than dry-bulb temperature of outside air immediately downstream of DOAS’s cooling coil

• DOAS must be designed and controlled to be in operation during all occupied periods, but not necessarily unoccupied periods

• Ventilation air does not require humidification regardless of how it is provided into facility

• System controls must monitor the DOAS cooling coil leaving air temperature and unit discharge air temperature regardless of which point is used for control

• A visual alarm must be initiated upon detection of cooling coil leaving air temperature being equal to or greater than 5° F above design dew point temperature at the Operator work station (OWS) or at DOAS for construction without an OWS

3-2.4 Additional Requirements.

Additional requirements are as follows:

• Zone terminal heating / cooling equipment must have occupant control and may be subject to intermediate season heating / cooling curtailment as directed by installation or command policy

• A vapor transmission (hygrothermal) analysis must be provided in accordance with UFC 3-101-01 /4/

3-3 \6\ [FOR AIR FORCE PROJECTS ONLY] VENTILATION AIR.

These requirements apply to Air Force projects. Final determination of equipment’s dehumidification capabilities is subject to approval by the Air Force subject matter expert (SME) as applicable based on submitted equipment selections, control sequences, and psychrometrics.

Change 8, 21 July 2021

A Dedicated Outdoor Air System (DOAS) is the only allowed method for providing dehumidification of ventilation air (outside air) when replacing an existing DOAS delivering any quantity of ventilation air or when the sum of all ventilation air into facility is greater than 750 cfm (354 L/sec) and the 1% occurrence humidity ratio (as documented in the official engineering weather data, or EWD) is above the inside cooling load design dew-point temperature of 57.9°F.

3-3.1 DOAS Requirements.

Systems must be selected, designed, and controlled as follows:

• Cooling coil must be selected to meet outside air sensible and latent loads plus space latent load

• Cooling coil must be selected and controlled to maintain a continuous coil leaving air temperature no greater than 55.0 °F

• Reheat coil must be selected and controlled to maintain a unit discharge air temperature equivalent to the facility average design temperatures for comfort cooling and comfort heating

(73.0 °F for 78.0 °F comfort cooling / 68.0 °F comfort heating)

• DOAS must not be subject to intermediate season (no-heat / no-cool) shutdown

• DOAS must distribute airflow directly to zones

• DOAS air inlets and outlets must deliver airflow quantities equal to or greater than 50 cfm (1400 L/min) at flow velocities between 400 – 800 ft/min (2 – 4 m/sec) through each device to allow for proper system balancing

• DOAS cooling coil leaving air temperature must be reset to 73°F and reheat coil de-energized when dew-point of outdoor air is at or below 57.9°F

• DOAS must be provided with energy recovery devices in accordance with

ASHRAE 90.1

• Energy recovery devices must be controlled to never increase energy (enthalpy) of outside air when energy of outside air upstream of energy recovery device is greater than energy of outside air immediately downstream of DOAS’s cooling coil

• Energy recovery devices must be controlled to never decrease dry-bulb temperature of outside air when dry-bulb temperature of outside air upstream of energy recovery device is less than dry-bulb temperature of outside air immediately downstream of DOAS’s cooling coil

• DOAS must be designed and controlled to be in operation during all occupied periods

Change 8, 21 July 2021

• Ventilation air does not require humidification regardless of how it is provided into facility

• System controls must monitor the DOAS cooling coil leaving air temperature and unit discharge air temperature regardless of which point is used for control

• A visual alarm must be initiated upon detection of cooling coil leaving air temperature being equal to or greater than 5° F above design dew point temperature at the Operator work station (OWS) or at DOAS for construction without an OWS

• A vapor transmission (hygrothermal) analysis must be provided in accordance with UFC 3-101-01

3-3.2 General Ventilation Requirements.

If a DOAS is not required, ventilation air may be brought in through the primary HVAC system only if the system is configured to continuously supply ventilation air. /6/

3-4 \4\ \2\ [FOR ARMY PROJECTS ONLY] VENTILATION AIR AND USE OF

DOAS.

\6\ When the 1% occurrence humidity ratio (as documented in the official engineering weather data, or EWD) for the outside air (OA) is greater than the inside cooling load design set-point (78°F, 57.9°F dew-point) humidity ratio, dehumidification of outdoor air is necessary and a Dedicated Outdoor Air System (DOAS) must be one of the three solutions included by the designer as described in the Appendix E - HVAC System Selection Flow Chart to address the humidity. Conditioning more humid air to design set points and the associated reheat can result in a DOAS being more Life Cycle Cost Effective (LCCE).

The DOAS must also be one of the three solutions included when the ventilation air for the building is 1000 CFM or greater. When larger volumes of ventilation air are required the DOAS may be more LCCE.

The required DOAS solution must apply to new and renovation projects.

Life cycle cost analyses (LCCA) must be performed to include a DOAS. The calculations must show the Energy Use Index (EUI) for the DOAS as well as the other solutions.

For buildings that may be unoccupied for extended periods of time, a DOAS may be necessary to maintain humidity conditions in the building to avoid mold growth or moisture damage during such time periods. An example building would be a barracks for which the assigned unit deploys. Coordinate with the installation Directorate of Public Works or component equivalent to determine when this is necessary. When this is required, ensure that the DOAS is designed, including capacity and controls, to properly dehumidify the building.

Change 8, 21 July 2021

The DOAS coils must be designed to condition OA, occupant and space loads.

An alarm must be included with the HVAC controls that would indicate if the outside air damper failed to open during occupied period.

A DOAS is required whether or not life cycle cost effective per the following paragraphs:

When zone sensible cooling systems (e.g. fan coil units, chilled beams, heat pumps, etc.)

are employed, Dedicated Outdoor Air Systems (DOAS) must be utilized to dehumidify all outside air for conditioned spaces. Use of DOAS may be applicable for use with central air handling systems when LCCE. The DOAS will separate the ventilation function from the space air conditioning function, (refer to Appendix F). Size the DOAS to condition the ventilation air necessary to remove the latent heat from the ventilation air and the latent heat from the space. The DOAS cooling coil must be sized using the 0.4 outdoor peak dew point design value and it’s Mean Coincident Dry Bulb (MCDB) for the outside air conditions in accordance with ASHRAE Fundamentals Handbook. Coil loads must be checked against peak conditions. /6/

On DOAS units, system controls must monitor the discharge temperature to prevent condensation in the space or zone. Provide energy recovery devices where life-cycle cost-effective or where required by ASHRAE 90.1.

Consider the following when completing your Life Cycle Cost Analysis (LCCA) of your HVAC systems selection:

- The additional outside air required per ASHRAE 62.1 for VAV systems that condition ventilation air (multiple space equation).

- Fan coil unit maintenance considering the available capacity of maintenance staff

- Cost saving from the energy savings of fan coil unit or VAV (recirculated air) cycling

(as stated above)

- The HVAC system application, (e.g. fan coil units may not be practical for a large open- space layouts or mission applicable).

- The loss of the ability to provide air-side economizer to include the added cost (incl.

maintenance) for water side economizer.

/2/ /4/

3-5 HEATING AND COOLING LOAD CALCULATIONS.

Heating and cooling system design loads for the purpose of sizing systems, appliances and equipment must be determined in accordance with the following requirements.

\2\ The HVAC design analysis for new facilities or renovation of existing facilities must include a psychrometric analysis documenting that the system meets design criteria.

The analysis must provide calculations of system cooling load, energy/mass transfer through conditioning equipment and fans, and a system schematic indicating state point dry bulb and wet bulb temperatures (or humidity ratios) of outside air, mixed air, supply

Change 8, 21 July 2021 air, and return air flow streams. The system must provide the capability to condition ventilation air and maintain space relative humidity over the full range of cooling load.

/2/

3-5.1 Load Calculations.

Heating and cooling system design loads must be determined in accordance with the calculation procedures described in the ANSI/ASHRAE/ACCA Standard 183 unless otherwise specified herein.

Provide no more than a \1\ 1.15 /1/ safety factor for heating equipment and distribution sizing to account for morning warm-up.

Change 8, 21 July 2021

3-5.2 Outdoor Design Conditions.

Use UFC 3-400-02 for outdoor design conditions \2\ for Navy projects. For Army and Air Force projects, use ASHRAE Fundamentals Handbook or UFC 3-400-02. /2/

3-5.2.1 \1\ Spaces /1/ Conditioned for Comfort Cooling.

Size equipment and all system components to maintain and control indoor design conditions at each of the following: (1) the 1.0 percent dry bulb and the corresponding mean coincident wet bulb (MCWB) temperature and (2) the 1.0 percent humidity ratio and corresponding mean coincident dry bulb (MCDB) temperature.

3-5.2.2 \1\ Spaces /1/ Conditioned for Specialized Technical Requirements.

Size equipment and all system components to maintain and control indoor design conditions at each of the following: (1) the 0.4 percent dry bulb temperature and the corresponding MCWB temperature and (2) the 1.0 percent humidity ratio and corresponding MCDB.

3-5.2.3 \1\ Spaces /1/ Conditioned for Comfort Cooling Using Evaporative Equipment.

Size equipment and all system components to maintain and control indoor design conditions at each of the following: the 1.0 percent wet bulb temperature and corresponding MCDB.

3-5.2.4 \1\ Spaces /1/ Conditioned for Comfort Heating.

Size equipment and all system components to maintain and control indoor design conditions at the 99 percent dry bulb temperature.

3-5.2.5 Condensers and condensing units.

For \1\ sizing condensers and condensing units, add 5°F (3°C) to the outdoor dry bulb temperature. /1/

3-5.3 Indoor Design Conditions.

Indoor cooling and heating conditions are determined as follows \1\ unless specified in a facility type UFC or as approved by the authority having jurisdiction (AHJ). /1/

3-5.3.1 \1\ Spaces /1/ Conditioned for Comfort Cooling.

\4\ 78.0° F (25.6 °C) dry-bulb / 57.9° F (14.4 °C) dewpoint / 50-percent relative humidity.

/4/ The design must take into account the moisture gain in the space.

Change 8, 21 July 2021

3-5.3.2 \1\ Spaces /1/ Conditioned for Comfort Cooling Using Evaporative Equipment.

80°F (26.7°C) dry bulb and a maximum of 55°F (12.8°C) dew point.

3-5.3.3 \1\ Spaces /1/ Conditioned for Comfort Heating.

68°F (20°C) dry bulb.

During unoccupied hours, temperatures must be set no higher than 55°F (12.8°C).

\1\ Provide humidification where the indoor relative humidity for comfort heating is expected to fall below 30 percent at design conditions. /1/ Coordinate with the architect to design the building envelope to prevent condensation in the wall/roof systems during the time humidification is in operation. Include in the design analysis a dew point analysis profile (ASHRAE Fundamentals Chapter 23) for winter design conditions, showing condensation boundaries. The dew point analysis must consider the effect of air movement into the walls for buildings under positive pressurization relative to the outdoors.

3-5.3.4 \1\ Spaces /1/ Conditioned for Heating - High to Moderate Physical Activity.

55°F (12.8°C) dry bulb. Examples of these facilities include areas in maintenance shops where engines are rebuilt and aircraft shops where instrumentation is repaired, warehouses areas where there are forklift loading operations, and aircraft hangars with high bay areas and limited amounts of people.

3-5.3.5 \1\ Spaces /1/ Conditioned for Heating - Freeze Protection.

40°F (4.5°C) at the 99.6 percent dry bulb outdoor design temperature.

3-5.3.6 \1\ Spaces /1/ Which are Naturally or Mechanically Ventilated Only \1\ for Comfort. /1/

80°F (26.7°C) dry bulb and 55°F (12.8°C) dew point maximum and 68°F (20°C) dry bulb minimum.

3-5.3.7 \1\ Spaces /1/ Conditioned for Process Cooling and Heating.

Process cooling and heating indoor design conditions are determined by the respective process requirements.

3-6 SPECIFIC FACILITY-TYPE HVAC REQUIREMENTS.

3-6.1 Facility Air Conditioning Eligibility.

Facilities are eligible for air conditioning where facilities of similar structure and function in the local private sector are equipped with air conditioning.

Change 8, 21 July 2021

\6\ Air conditioning for comfort cooling is not allowed for the following facilities \1\ unless approved by the AHJ for Army and Air Force projects. /1/ Air conditioning for comfort cooling is not allowed for the following facilities unless required to meet ASHRAE 55 for occupied spaces and work areas for Navy projects. /6/ Comfort conditioning is allowed in administrative areas of these facilities.

• Motor vehicle storage garages

• Aircraft maintenance facilities & hangars

• Special areas requiring high ventilation rates (i.e., woodshops, paint booth) \1\ unless approved by the AHJ /1/

• Vehicle storage areas of crash and fire stations

• Boiler plants and rooms

• Greenhouses

• General Warehouses

\6\ For Navy projects only: Evaluate air conditioning for work areas to determine most life cycle cost effective approach. Include equipment that will contribute to generating heat loads when sizing air conditioning equipment. Consult with end user on operations that will occur in work areas that may also contribute to sizing air conditioning equipment.

For Army projects only: Manufacturing or maintenance processes may require temperature and humidity air conditions that need to be considered when determining the eligibility for comfort cooling. Cooling can be provided if the 1% occurrence temperature or humidity set point is above the temperature or humidity set point required by the equipment manufacturer or maintenance process. Comfort cooling for the aforementioned facilities can be considered on a case by case basis if cooling is common in industry for that type of facility but must still be approved by the AHJ. /6/

3-6.2 Natural or Mechanical Ventilation Requirements.

In areas where mechanical or natural ventilation may be feasible, evaluate the use of these methods in lieu of other air conditioning methods to meet interior design conditions. Ambient noise levels and the availability of prevailing winds should be addressed in the evaluation. Include the effect of outdoor humidity levels when designing the mechanical ventilation systems.

3-6.3 Nonpermanent Construction.

The design of air conditioning for semi-permanent or temporary facilities must be on a minimum cost basis with exposed duct work, electrical work, and refrigerant or water piping and all other possible economies used. See UFC 1-201-01 for temporary contingency operations facility requirements.

Change 8, 21 July 2021

3-6.4 Intermittent Occupancy Facilities.

Facilities such as reserve centers, chapels, auditoriums, and theatres are occupied at irregular or infrequent intervals. Typically, only a small portion of a reserve center is occupied during normal working hours, while the balance of the facility is used primarily for weekends only. Consider the anticipated occupancy pattern when developing equipment layout and sequence of operation in order to ensure that overall life cycle cost is minimized. Evaluate opportunities such as thermal storage systems and demand controlled ventilation by occupancy sensors for these facility types. \6\ /6/

3-6.5 Vestibules.

Vestibules must be heated to 50°F (10°C) to melt tracked-in snow in locations where conditions warrant. Otherwise, vestibules must not be heated or air conditioned.

3-6.6 Closets and Storage in Air Conditioned Facilities.

These areas must be either directly air conditioned (greater than 50 sq. ft (4.6 sq.

meters) of floor space) or provided with exhausts to transfer conditioned air from adjacent spaces (lesser than 50 sq. ft (4.6 sq. meters) of floor space).

3-6.7 Aircraft Maintenance Shops.

Provide air conditioning for those functional areas where required for quality control of equipment, material, and task. \1\ Localized or spot air conditioning is allowed at individual workstations. /1/

3-6.8 Data Processing Centers and \1\ Server Rooms. /1/

HVAC designs for data processing centers \1\ and server rooms must follow DOE- FEMP “Best Practices Guide for Energy-Efficient Data Center Design unless specific manufacturer’s guidance exceeds the criteria contained within. /1/

3-6.9 Health Care Facilities.

HVAC designs for health care facilities will be in accordance with the current issue of

UFC 4-510-01.

3-6.10 Laboratories.

The design of HVAC systems must provide control over space temperature conditions including contaminants and fume control appropriate to the space function. \1\ /1/Exhaust systems must be provided with fume hoods to remove toxic substances as near to the source of the fumes as practical. Hood and system design must follow the recommendations of the following manual from the American Conference of Government Industrial Hygienists (ACGIH): ACGIH Industrial Ventilation: A Manual of Recommended Practice. Where laboratories are required to be under a negative

Change 8, 21 July 2021 pressure relative to other areas in the facility, coordinate with the architect to locate these spaces in the interior to prevent negative pressure induced infiltration of outdoor air into exterior wall cavities. Medical labs must meet the requirements of UFC 4-510- 01.

3-6.11 Fitness Centers.

HVAC designs for Fitness Centers will be in accordance with this document and the current issue of \6\ UFC 4-740-02 /6/.

3-6.12 General Purpose Aircraft Hangars.

\6\ HVAC designs for general purpose aircraft hangars will be in accordance with the current issue of UFC 4-211-01. /6/ 3-6.13 Aircraft Fire and Rescue and Fire Station.

\1\ Provide fire apparatus vehicle exhaust removal systems in all new, rehabilitated, or self-help Aircraft Fire and Rescue Station and Fire Stations. Projects must prevent exposure of fire fighters and contamination of living and sleeping areas to exhaust emissions. /1/ As required by NFPA 1500, such systems must permit the operation of the apparatus with the apparatus doors closed. \6\ Refer to UFC 4-730-10. /6/

3-6.14 \6\ Telecommunications Rooms.

HVAC designs for telecommunications rooms will be in accordance with UFC 3-580-01.

/6/

Change 8, 21 July 2021

3-6.15 Laundries and Dry Cleaners.

Mechanical ventilation will generally be the primary method of heat dissipation.

Evaporative cooling may be provided where effective. Spot air conditioning or general air conditioning must be provided to keep the temperature in the work areas from exceeding 85°F (29°C). Coil discharge temperatures used in spot cooling must be 50°F (10°C) dry bulb maximum for maximum dehumidification. Where life cycle cost effective, use heat recovery equipment on exhaust air to temper makeup air in cold weather \2\ to reduce the energy consumption /2/. \1\ Provide a readily accessible clean-out in all dryer exhaust ducts. /1/

3-6.16 Dining Facilities.

HVAC designs for Dining Facilities will be in accordance with this document, the following requirements, and the current issue of FC 4-722-01N and FC 4-722-01F.

Provide fire suppression system for hoods in accordance with UFC 3-600-01.

3-6.16.1 Kitchen Ventilation.

Comply with NFPA 96. No air must be returned from the kitchen to the HVAC system.

Generally, air flows from the dining areas to the kitchen areas to provide make-up air for kitchen exhausts. Maximize the use of dining area make-up air to the kitchen as this will provide secondary cooling for the kitchen staff. Kitchen hoods with built-in make-up air must be of the horizontal face discharge type.

Localized air conditioning or general air conditioning must be provided to keep temperature in the work areas from exceeding 85°F (29°C) dry bulb, if the main portion of the facility is air conditioned and the criteria for exhaust ventilation are met. Provide a separate ventilation system for the dishwashing area. Furnish tempered 65°F DB minimum (18°C DB minimum) makeup air for the range hood exhaust. The design must not allow recirculation of more than 75 percent of air (excluding hood exhausts) in the kitchen at any time. Kitchen canopy hood exhaust ventilation rates must be 75 fpm (0.4 m/s) for grease filter sections, and 50 fpm (0.25 m/s) for open hood section, measured at the horizontal hood opening. As an alternative, internal baffle-type canopy hood with peripheral slot and a slot velocity of 500 fpm (2.5 m/s) must be provided. Electrically interlocked supply and exhaust air fans must be designed for \1\ at least /1/ 2-speed operation. \1\ Commercial kitchen Type I or Type II hoods for systems over 1000 CFM must be provided with variable speed, demand control for exhaust air. /1/ Provide control interlocks for supply and exhaust fans to ensure that the HVAC system balance is maintained and that the proper direction of airflow is maintained during normal operations. Do not use evaporative coolers on kitchen supply air in humid areas

If additional make-up air is required for kitchen exhausts, provide push-pull kitchen hoods with built-in heated make-up air supply.

Change 8, 21 July 2021

3-6.16.2 Ductwork for Humid Dishwasher Room Exhaust.

Dishwasher room exhaust ducts must be as short as possible with direct runs to outside of building. Ductwork must \1\ be aluminum or stainless steel and /1/ have watertight joints, and must have a drain line from the low point. Approximately 25 percent of the exhaust air must be exhausted from the ceiling level.

3-6.16.3 Heat Recovery for Kitchens.

When heat in kitchens rejected by refrigeration equipment exceeds 10,551 W (36,000 Btuh), heat recovery systems must be used \1\ unless not /1/ life cycle cost effective.

\4\ \3\

3-6.17 Variable Refrigerant Flow (VRF) Systems.

VRF systems are a relatively new technology with design considerations and requirements that may differ from traditional HVAC systems.

\8\/8/

\8\See paragraph 1-8 for Open Control System Requirements. /8/ \6\ As of the publication date for this UFC, all known commercially-available VRF systems rely on a proprietary network with a gateway to provide Open protocol interface; this arrangement does not comply with the UFGS requirements for open protocols. UFC 3-410-02 includes a process by which specific systems can be excepted from some of the open protocol requirements and permitted to use proprietary communications between system components with a gateway or interface meeting the open protocol requirements. /6/

Change 8, 21 July 2021

3-6.17.1 Design Requirements for VRF Systems.

1. \6\ VRF systems must meet the control system specifications, or the system must be identified for an exception in accordance with UFC 3-410-02. /6/

2. The design must not preclude competition between vendors:

a. Since VRF systems from different manufacturers require different mechanical designs, provide a design with necessary design allowances to permit multiple manufacturers to meet the design.

For example, piping designs differ between VRF manufacturers so do not require specific VRF piping design, but rather indicate where piping may be installed.

b. Edit project specifications and requirements to include contractor design drawings as additional pre-construction drawing SD-02 Shop Drawing submittals. These drawings must document the details of the VRF design, including but not limited to piping layout.

3. Designs must require that the system be configured and installed strictly in accordance with the manufacturer’s installation requirement \7\ with the exception of press-fittings, which are not permitted per paragraph #5 below.

/7/

4. Include and require refrigerant line vibration isolation at all connections to motorized equipment, including but not limited to the refrigerant line connections at each fan coil unit.

5. VRF systems piping/tubing must have all brazed connections that meet ASME B31.5 requirements and the manufacturer’s installation requirements.

The list of fittings and joints that are prohibited include but are not limited to the following: push-on fittings, extruded fittings, flare fittings, press-connect fittings, mechanical joints and groove joints. The VRF system must be pressure tested and vacuum tested.

6. VRF systems must be provided to meet ASHRAE 15 and IMC safety requirements pertaining to leakage to rooms and spaces. Calculations must be performed per IAW ASHRAE 15 and IMC and must be provided to demonstrate these requirements are met.

7. The total refrigerant charge of the independent VRF system must be \8\ in compliance with the latest EPA Section 608 Refrigerant Management Regulations. (See paragraph 1-9 EPA HFC-Refrigerant Regulations /8/ for more information on EPA regulation and refrigerant leakage concerns.)

Change 8, 21 July 2021

3-6.17.2 Additional Considerations for VRF Systems.

3-6.17.2.1 Life-Cycle Cost Analysis.

Life Cycle Cost analysis comparing VRF with traditional systems can be difficult given the relative newness of VRF systems, and given that many VRF systems can only be serviced by factory-trained technicians which affects the maintenance costs for the system compared to more traditional systems. When performing life cycle cost analysis for VRF systems use care to properly identify all operation and maintenance costs. See APPENDIX B for more information on considerations regarding life-cycle costs.

3-6.17.2.2 Coordination with Project Site.

As with any system, coordinate the design of a VRF system with the government representative for the project. This is particularly important for VRF systems because their complexity can introduce operational, maintenance and cybersecurity challenges that are not necessarily experienced by traditional HVAC systems. For example: a higher level of training and expertise required to repair the system; differences in capability to operate the system in a degraded or manual mode; safety and operational considerations of running refrigerant lines through occupied spaces.

/3/ /4/

3-7…