1b.UFC_3-110-03_Roofing.pdf

UFC 3-110-03

01 May 2012

Change 1, 22 May 2014

UNIFIED FACILITIES CRITERIA (UFC)

ROOFING

APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED

ROOFING

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 COMMAND (Preparing Activity)

AIR FORCE CIVIL ENGINEER SUPPORT AGENCY

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

Change No. Date Location 1 22 May 2014 1-8.4, 2.2, 2-3.5, 2-3.6, 2-5.1, 2-8.1.3, 6-9.2:

Miscellaneous editorial changes 2-8.3: Thickness of weldable thermoplastic membranes changed to 60 mil (1.52 mm) 5-2.4: Insulated metal roof panels allowed in limited circumstances.

6-3.1, 6-3.2, 6.4: MREC rewritten

This UFC supersedes UFC 3-110-03, dated 26 September 2006, UFC 3-320-03A, dated 1 March 2005 with Change 2 dated October 2010, UFC 3-330-02A, dated 1 March 2005 and MIL-HDBK-1001/5, dated 28 February 1990.

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 Command (NAVFAC), and 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/.

Refer to UFC 1-200-01, General Building Requirements, for implementation of new issuances on projects.

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

TERRY G. EDWARDS, P.E. MICHAEL McANDREW Director, Air Force Center for Engineering and the Environment

Director, Facility Investment and Management

Department of the Air Force Office of the Deputy Under Secretary of Defense (Installations and Environment) http://www.wbdg.org/pdfs/ufc_implementation.pdf http://www.wbdg.org/ccb/browse_cat.php?o=29&c=4 http://dod.wbdg.org/

NEW DOCUMENT SUMMARY SHEET

Subject: UFC 3-110-03, Roofing, dated 1 May 2012.

Cancels: UFC 3-110-03, Roofing, dated 26 September 2006, UFC 3-320-03A, Structural Considerations for Metal Roofing, dated 1 March 2005 with Change 2 dated October 2010, UFC 3-330-02A, Commentary On Roofing Systems, dated 1 March 2005 and MIL-HDBK-1001/5, Roofing and Waterproofing, dated 28 February 1990 .

Description of Changes: UFC 3-110-03 updates the roofing design criteria for DOD.

Reasons for Changes:

• Updated to coordinate with the latest editions of the National Roofing Contractor Association’s Roofing Manual and Metal Building Manufacturer's Association Roofing Manual and to meet the latest DOD requirements.

Impact: There are negligible cost impacts. However, the following benefits should be realized.

• By using the current industry standards, designers and contractors will be more familiar with the criteria.

• Continuing to rely on commercial standards minimizes the need for future revisions.

i

TABLE OF CONTENTS

CHAPTER 1 INTRODUCTION

1-1 PURPOSE AND SCOPE

1-2 APPLICABILITY

1-3 GENERAL BUILDING REQUIREMENTS

1-4 CONTENTS

1-4.1 System Design

1-4.2 Appendices

1-5 BACKGROUND

1-6 SYSTEM SELECTION

1-6.1 New Construction

1-6.2 Existing Structures

1-7 SYSTEM TYPES

1-8 GENERAL DESIGN REQUIREMENTS

1-8.1 Unified Facilities Guide Specifications (UFGS)

1-8.2 Wind Resistance Rating

1-8.3 Thermal Expansion

1-8.4 Air and Vapor Barriers

1-8.5 Elimination, Prevention or Control of Fall Hazards

1-8.6 Roof Hatches

1-8.7 Skylights

1-8.8 Cool Roofs

1-8.9 Photovoltaic Systems – Rack Mounted Systems

1-8.10 Design Professional Qualifications

1-8.11 Warranty Requirements

1-8.12 Roof Information Card

CHAPTER 2 LOW-SLOPE ROOFING DESIGN REQUIREMENTS

2-1 GENERAL

2-2 DESIGN-BUILD

2-3 GENERAL LOW-SLOPE ROOFING REQUIREMENTS

2-3.1 Positive Drainage

2-3.2 Roof Curb Heights ii

2-3.3 Horizontal Roof Top Duct Work

2-3.4 Snow and Ice

2-3.5 Hail

2-3.6 Vegetative Roofing Systems

2-4 ROOF DECKS

2-4.1 Deck Slope

2-4.2 Types of Roof Decks

2-5 RIGID BOARD ROOF INSULATION

2-5.1 General

2-5.2 Types of Roof Insulation

2-6 COVER BOARDS

2-6.1 General

2-6.2 Types of Cover Boards

2-7 OVERVIEW OF ROOF MEMBRANES

2-7.1 Types of Membranes

2-7.2 Other Roof Membranes

2-8 GUIDANCE FOR ROOF MEMBRANES

2-8.1 Asphalt Built-Up Roof (BUR) Membranes

2-8.2 Modified Bitumen (MB) Membranes

2-8.3 Ethylene Propylene Diene Monomer (EPDM) Membranes

2-8.4 Weldable Thermoplastic Membranes

2-8.5 Hot Rubberized Reinforced Fluid-applied Membranes

2-8.6 Thermoplastic Polyolefin (TPO)

2-9 LOW-SLOPE CONSTRUCTION DETAILS

CHAPTER 3 STEEP-SLOPE ROOFING DESIGN REQUIREMENTS

3-1 GENERAL

3-2 DESIGN-BUILD

3-3 GENERAL STEEP-SLOPE ROOFING REQUIREMENTS

3-3.1 Self-Adhering Underlayment

3-3.2 Overhangs

3-3.3 Curb Heights

3-3.4 Metal Flashing iii

3-3.5 Gutters and Downspouts

3-3.6 Snow and Ice Considerations

3-3.7 Hail Resistance

3-3.8 Fall Protection

3-4 ASPHALT SHINGLES

3-4.1 Wind Pressure

3-4.2 Perimeter Drip Edge

3-4.3 Valley Flashing

3-4.4 Underlayments

3-5 TILE ROOFING

3-5.1 Slope

3-5.2 Fasteners

3-5.3 Flashing

3-5.4 Perimeter Drip Edge

3-5.5 Batten Boards

3-5.6 Snow Guards

3-5.7 Roof Cement

3-5.8 Self-Adhering Underlayment

3-5.9 Felt Underlayment

3-6 SLATE ROOFING

3-6.1 Roof Cement

3-6.2 Self-Adhering Underlayment

3-6.3 Felt Underlayment

3-6.4 Snow Guards and Fences

3-7 OTHER STEEP-SLOPE ROOFING

3-8 STEEP-SLOPE CONSTRUCTION DETAILS

CHAPTER 4 ROOF SYSTEM RELATED SHEET METAL FLASHINGS

4-1 GENERAL

4-2 REFERENCE STANDARDS

4-3 SHEET METAL

4-3.1 Sheet Metal Type

4-3.2 Sheet Metal Gauge and Thickness iv

4-3.3 Organic Coatings

4-4 MATERIAL COMPATIBILITY

4-5 EXPANSION AND CONTRACTION

CHAPTER 5 STANDING SEAM METAL ROOFING SYSTEM DESIGN

REQUIREMENTS

5-1 INTRODUCTION

5-2 GENERAL REQUIREMENTS

5-2.1 Design-Build

5-2.2 Panels Type

5-2.3 Overhangs

5-2.4 Insulated Metal Panels

5-2.5 Corrosion Treatment

5-2.6 Organic Coatings

5-2.7 Metal Thickness

5-2.8 Panel Attachment

5-2.9 Flashings and Penetrations

5-2.10 Other Rooftop Appurtenances

5-2.11 Wind Design

5-3 HYDROSTATIC SYSTEM REQUIREMENTS

5-3.1 General

5-3.2 Material

5-3.3 Panel Type

5-3.4 Slope

5-3.5 ASTM Test Method

5-3.6 Hydrostatic Specifications

5-3.7 Recommended Hydrostatic Construction Details

5-4 HYDROKINETIC SYSTEM REQUIREMENTS

5-4.1 General

5-4.2 Material

5-4.3 Panel Type

5-4.4 Flashing Details

5-4.5 Slope

5-4.6 Hydrokinetic Roofing Specifications v

5-4.7 Recommended Hydrokinetic Construction Details

CHAPTER 6 RE-ROOFING REQUIREMENTS

6-1 OVERVIEW

6-2 GENERAL CONSIDERATIONS

6-2.1 Terminology

6-2.2 Life Cycle Cost Analysis

6-2.3 Low-sloped Versus Steep-Sloped Considerations

6-3 MESH REINFORCED ELASTOMERIC ROOF COATINGS (MREC)

6-4 LOW-SLOPE ROOFING REMOVAL AND REPLACEMENT

6-4.1 Analysis of Existing System

6-4.2 Phenolic Foam Board Insulation

6-4.3 Testing for Asbestos Containing Materials (ACM)

6-4.4 Slope

6-5 REPLACING SINGLE-PLY SYSTEMS

6-6 LOW-SLOPE CONVERSIONS

6-7 TAPERED ROOF INSULATION SYSTEMS

6-8 RECOVERING STEEP-SLOPE ROOFS

6-8.1 Historic Buildings

6-9 METAL ROOFING

6-9.1 Metal Roofing Recover

6-9.2 Metal Roofing Overbuild

6-10 SPRAY APPLIED POLYURETHANE FOAM

6-10.1 Foam

6-10.2 Coating

6-11 NEW TRUSSES AND DECKING

6-12 SECONDARY PROTECTION

6-13 CLIMATE/WEATHER CONSIDERATIONS

6-13.1 Night Seals

6-13.2 Upgrading Insulation

6-14 LOGISTICAL CONSIDERATIONS

6-14.2 System and Site Safety Considerations

6-14.3 Deck Replacement vi

APPENDIX A REFERENCES

APPENDIX B BEST PRACTICES

B-1 INTRODUCTION

B-2 SUSTAINABILITY

B-2.1 21 TENETS OF SUSTAINABILITY

B-3 ROOFING SYSTEMS

B-3.1 LOW-SLOPE ROOF DRAINS

B-3.2 COVER BOARDS

B-3.3 COMMON METAL ROOF PANEL PROFILES

B-4 TEMPORARY ROOFS

B-5 ELECTRIC FIELD VECTOR MAPPING (EFVM)

B-5.1 HOW EFVM WORKS

B-5.2 LOCATING A BREACH IN THE MEMBRANE

B-6 RECYCLING

B-7 LIFE CYCLE ASSESSMENT

B-8 COOL ROOFING AND HEAT ISLAND ISSUES

B-9 GUTTERS AND DOWNSPOUTS

B-10 PARAPETS

B-11 DESIGN PROFESSIONAL QUALIFICATIONS

B-12 REROOFING

B-13 RECOVERING

APPENDIX C GLOSSARY, ACRONYMS AND ABBREVIATIONS

APPENDIX D WARRANTIES

D-1 GENERAL

D-2 WARRANTY TYPES

D-2.1 MANUFACTURERS’ WARRANTIES

D-2.2 GENERAL CONTRACTOR’S WARRANTIES (ONE TO FIVE YEARS).

D-2.3 ROOF INSTALLERS WARRANTY TO GENERAL CONTRACTOR

(ONE TO TWO YEARS)

D-3 BONDING

D-4 WARRANTY REVIEW

D-5 CONTRACTOR’S WARRANTY

vii

D-5.1 ROOF MANUFACTURER’S WARRANTY

D-5.2 WARRANTY CLAIM

D-6 CLOSE-OUT

D-7 BUILDING MAINTENANCE

D-8 POST-CONSTRUCTION ROOF MODIFICATIONS

APPENDIX E QUALITY ASSURANCE CONSIDERATIONS

E-1 GENERAL

E-2 DESIGN

E-3 SPECIFICATIONS

E-3.1 ROOF SYSTEM

E-3.2 MAINTAINABILITY

E-3.3 SUBMITTALS

E-3.4 ROOF MANUFACTURER INSPECTION

E-3.5 WARRANTY SELECTION

E-3.6 PRE-INSTALLATION/PRE-CONSTRUCTION MEETING

E-3.7 MINIMUM INSTALLER QUALIFICATIONS

E-4 FIELD INSPECTION(S)/CQM

E-4.1 INSTALLATION

E-4.2 LEAKS

E-5 CLOSE OUT OF CONTRACT

APPENDIX F OTHER RESOURCES

TABLES

TABLE 1-1. RELATIONSHIP WITH NRCA MANUAL

TABLE 2-1. LOW-SLOPE ROOFING CONSTRUCTION DETAIL LIMITATIONS

TABLE 3-1. STEEP-SLOPE ROOFING CONSTRUCTION DETAIL LIMITATIONS ... 27

TABLE 5-1. HYDROKINETIC METAL ROOFING CONSTRUCTION DETAIL

LIMITATIONS

TABLE 6-1. ALLOWABLE RECOVER OVER EXISTING ROOFING*

viii

FIGURES

FIGURE B-1. COMMON METAL ROOF PANEL PROFILES AND CLIPS

FIGURE B-2. BULB SEAM ZIP RIB

CHAPTER 1 INTRODUCTION

1-1 PURPOSE AND SCOPE.

Use this UFC in conjunction with the current editions of the National Roofing Contractors Association (NRCA) Roofing Manuals (NRCA Manual) and the NRCA technical bulletins and the Metal Building Manufacturers Association (MBMA) Metal Roofing Systems Design Manual (MBMA Roofing Manual) to provide specific design guidance for Military roofing projects. This UFC explains how to apply the NRCA Manual and the MBMA Roofing Manual to the design of Military projects (including Army, Navy, and Air Force).

1-2 APPLICABILITY.

This UFC is applicable to all military projects and planners, design professionals and contractors responsible for roofing planning, system design, installation, and maintenance. Family housing requirements may differ from the requirements stated herein. Where one Military Service's criteria vary from the other Services' criteria, it is noted in the text.

1-3 GENERAL BUILDING REQUIREMENTS.

UFC 1-200-01, “General Building Requirements”, provides applicability of model building codes and government-unique criteria for typical design disciplines and building systems, as well as for accessibility, antiterrorism, security, sustainability, and safety.

Use this UFC in addition to UFC 1-200-01 and the UFCs and government criteria referenced therein.

1-4 CONTENTS.

Roofing design begins with system selection documented in this UFC, the NRCA Manual, and the MBMA Roofing Manual.

1-4.1 System Design.

The NRCA Roofing Manual and the MBMA Roofing Manual provide information regarding the design and construction of roofing systems. However, because of the emphasis on low life cycle cost, this UFC limits the applicability of certain techniques permitted by NRCA and MBMA. The NRCA Roofing Manual CD 2010 comprises five volumes (collectively referred to as NRCA Manual). Table 1-1 illustrates the relationship of this UFC with the NRCA Manual. Use the MBMA Roofing Manual for the design of metal roof systems in combination with the NRCA Manual.

TABLE 1-1. RELATIONSHIP WITH NRCA MANUAL

Primary Design Criteria

Additional Criteria (Reference Only)

Chapter 2 - Low-slope Roofing Design Requirements (except metal roofing)

The NRCA Manual: Membrane Roof Systems – 2007 The NRCA Manual: Metal Panel and SPF Roof Systems – 2008 NRCA Construction Details CD –

Chapter 3- Steep-slope Roofing Design Requirements (except metal roofing)

The NRCA Manual: Steep-slope Roof Systems – 2009 NRCA Construction Details CD - 2010

Chapter 4 – Roof System Related Sheet Metal Flashing

The NRCA Manual: Architectural Metal Flashing, Condensation Control & Reroofing – 2010

SMACNA Architectural Sheet Metal Manual

Chapter 5 – Standing Seam Metal Roofing Design Requirements

MBMA Roofing Manual (for Hydrostatic systems) NRCA Construction Details CD – 2010 (for Hydrokinetic systems)

The NRCA Manual: Metal Panel and SPF Roof Systems – 2008 & SMACNA Architectural Sheet Metal Manual

Chapter 6 - Reroofing Requirements

The NRCA Manual: Architectural Metal Flashing, Condensation Control and Reroofing

1-4.2 Appendices.

Appendix A is a reference list. Appendix B provides background information and design best practices. Appendix C is the glossary of acronyms and abbreviations. Appendix D provides considerations on roof warranties. Appendix E provides quality assurance guidelines. Appendix F provides other resource documents.

1-5 BACKGROUND.

There are a variety of materials and roofing systems available. Satisfactory roofing performance comes from careful system and material selection, design, contract document preparation, specification, installation, and maintenance.

Roofing systems are exposed to the full brunt of the weather and can allow moisture intrusion or fail prematurely if not properly designed, installed, and maintained.

Moisture intrusion can be costly, adversely affect the functions within the building, and result in roof system failure. Since modern roofing systems contain considerable thermal insulation, moisture intrusion lowers thermal efficiency and hinders energy conservation. Wet materials support fungus or mildew, cause deterioration of other roofing system components, and can emit odors leading to sick buildings and occupants.

1-6 SYSTEM SELECTION.

There are two starting points in roofing system selection.

1-6.1 New Construction.

In new construction, the roof system selection is an integral part of the overall building design and must take into account interior building usage and climate. For example, the building can be designed to prevent outward moisture drive, support heavy roof systems (such as garden roofs or paver systems), or sloped for the desired durability (life cycle cost benefit) and aesthetic considerations.

1-6.2 Existing Structures.

See Chapter 6 for more information on reroofing. When dealing with existing structures, weight, slope, existing and hazardous materials, and historic preservation may become constraints. For example, the thickness, weight, and reflectivity of the roof system has a major impact on roof/structure as already designed. Further, with an occupied building, construction noises, fumes, fire hazards, and roof access all take on increased importance.

1-7 SYSTEM TYPES.

For the purposes of this UFC, roofing is categorized as low-slope, steep-slope and metal roofing. Low-slope roofing systems are weatherproof membrane types of roof systems installed on slopes at or less than 3:12 (14 degrees). Steep-slope roofing systems are water-shedding types of roof coverings installed on slopes greater than 3:12 (14 degrees). Standing-seam metal roofing (SSMR) systems are either hydrostatic that are designed and constructed to be totally water resistive (like a roof membrane) or hydrokinetic that are not totally resistive to water intrusion and rely on slope to shed water.

1-8 GENERAL DESIGN REQUIREMENTS

The following requirements apply to all military roofing projects, regardless of system type:

1-8.1 Unified Facilities Guide Specifications (UFGS).

All roofing projects, including both design-build and design-bid-build, shall be designed consistent with this UFC and requirements of the applicable UFGS. Design-bid-build projects are required to utilize the applicable UFGS. Appendix A lists the applicable UFGS documents.

1-8.2 Wind Resistance Rating.

The designer of record shall determine wind uplift pressures and dimensions of the corners, perimeter, and field of the roof in accordance with ASCE-7, Minimum Design Loads for Buildings and other Structures. Delineate calculated values in the roof specification or drawings. Utilize independently tested and rated roof systems, such as Factory Mutual (FM), Underwriters Laboratory (UL), and Single Ply Roofing Industry

(SPRI).

1-8.3 Thermal Expansion.

The design of the roof and building thermal expansion systems shall consider the selected roof system and shall comply with the roofing system manufacturer requirements.

1-8.4 Air and Vapor Barriers.

Coordinate the roofing design with UFC 3-101-01, “Architecture”, which provides design criteria for the building envelope as a whole, including the roof. UFC 3-101-01 includes requirements for air and vapor barriers associated with roofing systems as well as the required \1\ /1/ calculation to determine the need for a vapor retarder and to verify that the vapor retarder has been positioned correctly in the roof assembly. Care must be taken to maintain the continuity of the roof vapor retarder, which is critical to its performance. Moist air leakage through poorly installed vapor retarders defeats their purpose and creates interior moisture problems.

1-8.5 Elimination, Prevention or Control of Fall Hazards.

Any part or component of the building, facility, structure or equipment requiring future maintenance work at all roofs shall incorporate in the design fall prevention methods or techniques to eliminate fall hazards during occupancy and when performing maintenance work. The preferred order of control measures or the hierarchy of controls is to eliminate the need to work at heights (design out fall hazards), followed by prevention (installing guards) and protection and control of fall hazards by identifying, designing and installing anchorages (hard points) for safe use of fall arrest equipment and systems. The materials used in all fall protection equipment shall be selected for metal compatibility in order to minimize corrosion -- type 316 stainless steel is recommended.

Elimination, prevention or control of fall hazards shall comply with the provisions and requirements of American National Standards Institute, ANSI/ASSE Z359 Fall Protection Code, ANSI/ASSE A1264.1 Standard and DOL - 29 CFR Part 1910, Subpart D. For additional information, refer to Building Design Elements for Enhanced Fall Protection for Construction and Maintenance Personnel: An NRCA Perspective.

1-8.6 Roof Hatches.

All buildings over two stories, excluding family housing, shall have a roof hatch with an interior ladder or building-attached exterior ladder for roof access. This includes metal roof overbuilds. Provide roof hatches with fully lined and insulated curbs. Coordinate curb height with tapered insulation heights; standard curb height is 12 in. (305 mm), 16, 18, and 24 in. (405, 455, and 610 mm) are available. The height of the roof curb shall be selected to provide 8 inch minimum curbing above the surface of the roof. Also, provide ladders up to the roof hatch, ladder up safety posts, and safety rails per OSHA requirements. Coordinate with UFC 4-010-01, “DoD Minimum Antiterrorism Standards for Buildings”.

1-8.7 Skylights.

If skylights are included, specify fully lined and insulated curbs. Coordinate curb height with tapered insulation heights; standard curb height is 12 in. (305 mm), 16, 18, and 24

in. (405, 455, and 610 mm) are available. The height of the roof curb shall be selected to provide 8 inch minimum curbing above the surface of the roof. Skylight framing and flashing shall extend over and beyond the curb’s vertical wall.

1-8.8 Cool Roofs.

If a cool roof is selected, meet the ASHRAE 90.1 (2010) Chapter 5 values for cool roofing. If a cool roof is not selected in climate zones 1-3, meet one of the exception requirements listed in ASHRAE 90.1 (2010) Chapter 5 or provide thermal insulation above the deck with an R-value of 33 or greater.

Mechanically fastened single-ply roof systems shall comply with the requirements for mechanically fastened single-ply systems in Chapter 2. Condensation on the underside of mechanically fastened systems can result in ice build-up in winter, mold growth on the facers, moisture dripping into the interior, and replacement of the roofs with less than four years of service. See Appendix B for more information.

1-8.9 Photovoltaic Systems – Rack Mounted Systems

If a photovoltaic system is selected, the contractor shall adhere to the following guidelines:

• Building Owners Guide to Roof-mounted Photo Voltaic Systems published by NRCA.

• Guidelines for Roof-mounted Photovoltaic Systems published by NRCA.

The installation of a photovoltaic roof system over existing roof systems shall be undertaken with extreme caution. Planning and design efforts on PV systems located on roofs shall include the following:

• Determine if the existing roof structure can handle the anticipated roof load increase. Design to ensure that roof drainage is maintained considering the additional roof deflection due to load.

• Inspect and determine that the existing roof system has at least 10 years of service life remaining. If not, the existing roof shall be removed and a new replacement roof system designed in tandem with the photovoltaic system.

• If 10 years remaining service life remains, contact the warranty holder and involve them in the design of the intersecting details, required roof protection, re-inspections, and their requirements for maintaining the roofs guarantee.

• Design the roof related details for anticipated roof replacement work.

Coordinate with the photovoltaic system designer to anticipate and plan for future roof replacement.

• PV equipment on a roof places an entirely new set of roof protection requirements during initial installation and throughout the maintenance cycle. Specify a roof protection program to be applied during the PV system installation.

• PV supports shall be permanently affixed stanchions that are anchored to the building structure.

1-8.10 Design Professional Qualifications.

Both design-build and design-bid-build projects with more than 15,000 ft.2 (1400 m2) of roof area or that is defined as “critical use” or “mission critical” in the project DD Form 1391 shall have a Registered Roof Consultant (RRC) or a registered PE or RA that derives his or her principal income from roofing design on the quality control staff of the Design or Design-Build (DB) team.

1-8.11 Warranty Requirements.

Any new, permanent construction facility shall be designed and specified with a warranty that meets the following requirements:

• Has “no dollar limit,”

• Covers full system water-tightness,

• Is from the single source manufacturer, and

• Has a minimum duration of 20 years.

Manufacturers’ warranties that require periodic inspections or repairs at the Government’s expense to maintain the warranty are not permitted. The warranty terms, exclusions, and limits must be enumerated in the specifications and require that all roof curbs and penetration flashings \1\ (these include snow guard and lightning protection attachments) /1/ integrated into the roof system are covered under the warranty. For additional background on warrantees, refer to Appendix D.

1-8.12 Roof Information Card.

Per the UFGSs for each roof installation, furnish a typewritten information card for facility records and a card laminated in plastic and framed for interior display at roof access point.

This Page Intentionally Left Blank

CHAPTER 2 LOW-SLOPE ROOFING DESIGN REQUIREMENTS

2-1 GENERAL.

The NRCA Manual provides a wide range of information for design and construction of low-slope roofing assemblies. This chapter does not address low-slope metal roofing (see Chapter 5). This chapter reinforces particularly salient information with regard to military use or limits the applicability of certain techniques in the NRCA Manual. Where contents of the NRCA Manual are acceptable without modification, those sections are not mentioned herein.

2-2 DESIGN-BUILD.

Because of the wide variety of materials available and the variation in quality in similar materials, design-build contracts for low-slope roofing systems must name the specific desired low-slope roofing system (BUR, \1\ Modified Bitumen, MREC, /1/ EPDM, etc.)

and identify relevant performance requirements to be provided under the contract. It is not sufficient to simply specify a low-slope roofing system per this UFC.

2-3 GENERAL LOW-SLOPE ROOFING REQUIREMENTS.

2-3.1 Positive Drainage.

The minimum slope for construction of new buildings is ½:12 to achieve positive drainage. Consult with a plumbing engineer to determine the appropriate number of roof drains and the size of drain pipes. Retrofit drains are not permitted.

2-3.2 Roof Curb Heights.

Curbs height shall be a minimum of 8 in. (200 mm) above the roof surface, but shall not be less than 6 in. (150 mm) above the high point of a cricket. Roofs with slope may need additional crickets on the upslope side of all non-round penetrations to assure positive drainage around equipment. Crickets are required on the upslope side of all penetrations greater than 24-in. (610-mm) wide

2-3.3 Horizontal Roof Top Duct Work.

Horizontal roof-top ductwork shall have a minimum clearance of 18 in. (455 mm) above the roof plane to ensure ease of re-roofing. Ductwork larger than 48-in. (1220-mm) wide will require a minimum clearance of 24-in. (610-mm) and shall be coordinated with the HVAC engineer.

2-3.4 Snow and Ice.

Over-the-eaves drainage in cold climates can be problematic if snow and ice issues are not addressed early in the design process. Issues that designers shall address are contained in the Cold Regions Research & Engineering Laboratory (CRREL) report MP- 01-5663, Minimizing the Adverse Effects of Snow and Ice on Roofs.

Locate downspouts to avoid ice build-up on pedestrian circulation paths.

2-3.5 Hail.

Some geographical areas of the United States are more prone to severe hail events.

Roof assemblies shall be capable of resisting impact from reasonably expected hail storms for a given geographical area in accordance with IBC-2009 Paragraph 1504.7.

Typical enhancements include a thicker membrane combined with a rigid coverboard directly below the membrane.

Owners of critical facilities, such as hospitals, schools, computer centers, airports and sensitive government buildings have come to realize the importance of installing a hail resistant roof assembly over critical facilities. Hail-resistant roof assemblies shall incorporate high-density cover boards when fully-adhered roof covers are specified.

Examples of roof covers that have been shown to perform well in hail prone areas (up to 2-in. (50-mm) hail stone size) include the following:

• Aggregate surfaced built up roofing

• Aggregate surfaced modified bitumen

• \1\ /1/

• Fully adhered 90 mil (2.28 mm) EPDM

• Granule or smooth with coating polyester reinforced modified bitumen 2-3.6 Vegetative Roofing Systems.

Vegetative roof systems are a roof area of plantings/landscaping installed above a waterproofed substrate at any building level that is separated from the ground beneath by its manmade structure. A vegetative roof system consists of a waterproofing system and its associated components such as protection course, root barrier, drainage layer, thermal insulation and aeration layer, and an overburden of growth medium and plantings. See NRCA Vegetative Roof Systems for additional information.

Vegetative roof systems must be installed over newly installed roof systems and cannot be installed over existing roof systems. Knowledgeable selection of compatible building materials, quality vegetative roof system materials, and systems that will withstand the conditions of the location where a building is located are vital to a quality vegetative roof assembly design. Properly prepared contract documents with accurate drawings and details are essential. Vegetative roof systems shall be designed by an RRC or a registered PE or RA that derives his or her principal income from roofing design. Test the final assembly with a 48-hour water test per ASTM D5957 and/or using an electric field vector mapping (EFVM) system (see Appendix B for more info on EFVM).

Recommended waterproof membrane systems for use in vegetative roofs include:

• Hot fluid applied modified asphalt membrane, fabric reinforced – 215 mils minimum thickness

• Atactic polypropylene polymer (APP) and Styrene butadiene styrene (SBS) polymer modified bitumen sheet membrane, 2-layer minimum

• 1\ /1/

• PVC reinforced – 72 mils (1.82 mm) minimum thickness

2-4 ROOF DECKS.

2-4.1 Deck Slope.

For new construction, the minimum slope noted in Chapter 2, Positive Drainage, must be accomplished in the structural deck.

2-4.2 Types of Roof Decks.

2-4.2.1 Steel Decks.

Steel roof decks are common on military facilities. When properly designed, they provide an economical and dependable roof deck. They are lightweight and are particularly useful where relatively large clear spans are desired. Mechanically attach roof insulation for this type of roof deck. Design to prevent mechanical fasteners from backing out enough to disengage the deck. In addition, the design of the roof insulation must be tolerant of a small degree of fastener back out. Two layers of insulation are required. Depending on wind resistance requirements, all layers of insulation may be mechanically fastened or the bottom layer may be mechanically fastened and the top layer adhered. Wood fiberboard may not be in direct contact with steel decks.

2-4.2.2 Structural Concrete Decks.

Structural precast and poured-in-place concrete roof decks are also commonly used on military projects. They are heavy and are best suited to roof decks with relatively short spans. Use mechanically fastened insulation only when fully adhered roof systems will not meet the required wind uplift resistance. Due to the inherent moisture in the concrete, proper drying time is required. Ensure during system selection and installation that adequate bonding takes place between the roof system and the deck.

Prior to installing any roof system on a concrete deck, conduct a test per ASTM D4263.

The deck is acceptable for roof system application when there is no visible moisture on underside of plastic sheet after 24 hours.

2-4.2.3 Wood-Plank and Structural Wood-Panel Decks.

Wood-plank and structural wood-panel decks were used in the past on many military facilities. Generally, this material may only be used on small buildings or in reroofing when the existing material is in fair or better condition. Use of this material on new buildings must be supported with strong arguments demonstrating that neither steel nor structural concrete decks fulfill the specific functional requirements.

2-4.2.4 Cement-Wood Fiber Deck Panels.

Cement-wood fiber deck panels have limited utility due to concerns about moisture susceptibility. This type of deck shall not be used for new construction.

2-4.2.5 Lightweight Insulating Concrete Decks.

Lightweight insulating concrete decks have limited utility due to its hydroscopic nature and difficulty of reroofing. Do not use this type of roof deck for new construction.

2-4.2.6 Poured Gypsum Concrete Decks.

Poured gypsum concrete decks have limited utility due to difficulty in attaching membranes to the deck and difficulty in repair. Do not use this type of roof deck for new construction.

2-4.2.7 Precast Gypsum Panel Decks.

Precast gypsum panel roof decks have been used on many military facilities. However, where membrane leaks have occurred, these roof decks pose a safety hazard due to structural instability. Do not use this type of roof deck for new construction.

2-4.2.8 Thermosetting Insulating Fills.

Thermosetting insulating fills have limited utility. Do not use this type of roof deck for new construction.

2-5 RIGID BOARD ROOF INSULATION.

2-5.1 General.

Roof insulation is a very cost-effective means of reducing energy consumption.

Depending on climate and the type of membrane selected, the position of the insulation in the roof system greatly affects the performance of the roof system. Insulation system shall be selected and designed to meet the requirements in UFC 3-101-01, “Architecture”, and \1\ UFC 1-200-02, “High Performance and Sustainable Building Requirements”. /1/

2-5.2 Types of Roof Insulation.

2-5.2.1 Cellular Glass Insulation.

Cellular glass roof insulation is not widely used due to its high cost. It is most commonly used in cold storage facilities and other areas where excessive amounts of moisture would degrade the insulating capabilities of other types of insulation.

2-5.2.2 Perlite Board Insulation.

Perlite board insulation is commonly used and may be specified where factors other than insulating efficiency per unit thickness are the primary design considerations. It is particularly useful in roof assemblies where fire resistance is of primary concern and the potential for water vapor intrusion is limited. Perlite board shall not be used in high-wind areas.

2-5.2.3 Polyisocyanurate Foam Board Insulation.

Polyisocyanurate foam board is the most commonly used roof insulation. It is often specified where insulating ability is the primary design consideration. The minimum compressive strength of polyisocyanurate foam board shall be 25 psi (172 kPa).

2-5.2.4 Polystyrene Board Insulation.

Polystyrene board roof insulation is used by the military and is made in two types:

expanded polystyrene board (EPS) and extruded polystyrene board (XPS). In terms of moisture resistance and insulating capability, XPS is superior to EPS. It is also more expensive but appropriate for use in inverted membrane systems and cold storage facilities. Do not use polystyrene in direct contact with hot mopped systems. It is typically necessary to use underlayment board and cover board with polystyrene insulation in order to provide for necessary fire interior and exterior ratings and membrane adhesion properties, except when used as part of a loose-laid, inverted roof system assembly on concrete deck. When polystyrene is used on the interior of a building, it must be encased with a fire resistive material.

2-5.2.5 Composite Board Insulation.

Composite board roof insulation may be specified where a multiple layer type of insulation does not satisfy all design requirements, and where there are cost savings available from reducing the number of construction operations needed to install two different kinds of roof insulation. Single layer applications shall be limited when possible.

2-5.2.6 Phenolic Foam Board Insulation.

Phenolic foam board insulation causes severe corrosion when in contact with steel roof decks. It is no longer manufactured in the United States. Phenolic foam board insulation shall not be specified for use.

2-5.2.7 Tapered Insulation Systems.

Tapered rigid board roof insulation systems are more expensive per square unit than non-tapered insulation. As a result, do not use tapered insulation to create the primary slope in new construction. Use tapered insulation in crickets and saddles to ensure positive drainage when adequate drainage already exists in the roof deck as a whole.

The slope of crickets and saddles shall be twice that of the main slope.

2-6 COVER BOARDS.

2-6.1 General.

Coverboards installed directly below the roof membrane shall be used within all roof assembles except single-ply ballasted roof systems. Coverboards provide the following functions:

1. Separate incompatible material

2. Minimize the effects of thermal drift; and

3. Protect the thermal insulation and provide a rigid support for the roof membrane.

2-6.2 Types of Cover Boards.

2-6.2.1 Glass Mat Silicon-modified Gypsum Boards.

Provides improved impact and moisture resistance to roof covers and improved fire resistance.

2-6.2.2 High Density Wood Fiber.

Provides improved impact resistance to roof covers, but is hydroscopic in nature.

2-6.2.3 Paper-faced Gypsum Board.

This shall not be used as a cover board.

2-7 OVERVIEW OF ROOF MEMBRANES.

The NRCA Manual discusses all available roof membranes; however, some membranes do not provide the long-term performance requirements for military buildings. Some new products may not be judged suitable because of the lack of proven performance. Other existing membrane systems may not be suitable because experience has shown a lack of cost effectiveness over the required life cycle.

2-7.1 Types of Membranes.

Generally, low-slope roof membranes that are suitable for use by the military are limited to the following:

• Asphalt built-up roof membranes.

• Styrene butadiene styrene (SBS) or Atactic polypropylene polymer (APP) modified bitumen membranes.

• Ethylene propylene diene monomer (EPDM) single-ply membranes.

• Weldable thermoplastic polyvinyl chloride (PVC) single-ply membranes.

• Spray applied polyurethane foam (SPF) membranes.

• Hot rubberized reinforced fluid-applied membranes.

2-7.2 Other Roof Membranes.

Other roof membranes will be considered and evaluated on a case-by-case basis.

Thermoplastic Polyolefin (TPO) shall only be allowed on roofs with an anticipated life of 10 years or less. See additional guidance below for TPO.

2-8 GUIDANCE FOR ROOF MEMBRANES.

This Section provides requirements and considerations for the design and construction of the above roof membrane types. The use of any membrane type for which there is not a corresponding UFGS shall be considered on a case-by-case basis and approved by the project manager.

2-8.1 Asphalt Built-Up Roof (BUR) Membranes.

BUR systems have broad applicability for dependable low-slope roof systems with low service life cost. Consider this roof system unless it can be shown that it fails to meet important design criteria. Positive attributes of BUR membranes include:

• Durability with long service life

• Low maintenance

• Well-understood maintenance procedures However, the success of this roofing system is based upon sound installation techniques accompanied by suitable quality control. Quality control can be influenced by the warranty. More information on warranties may be found in Appendix D and more information on quality assurance may be found in Appendix E.

2-8.1.1 Cant Strips.

Provide cant strips for all built-up roof systems.

2-8.1.2 Fiberglass Mat Material.

BUR systems must use fiberglass mat material and no less than three-ply or as limited by the UFGS.

2-8.1.3 Roof Vents.

\1\ Ventilating base sheets are required on all concrete roof deck systems. Roof vents are not permitted for new construction. /1/

2-8.1.4 Types of BUR Membrane Surfacing.

The allowable types of top surfacing for BUR membranes are granulated modified bitumen cap sheet and aggregate.

2-8.1.4.1 Granulated Modified Bitumen Cap Sheet.

Ceramic granules reduce the temperature effect on BUR systems. However, as granules are lost, degradation due to ultraviolet (UV) radiation will negatively affect performance. Longevity of these systems on average is not as great as aggregate surfaced BUR systems.

2-8.1.4.2 Aggregate Surface.

The most common type of BUR surfacing is aggregate embedded in a bituminous flood coat. The thickness of 400 lb. (180 kg) gravel surfacing per square of roofing is 0.5 to

0.75 in. (12 to 18 mm). This surfacing allows the temperature of the BUR membrane to remain somewhat cooler than mineral surfaced cap sheet BUR systems. Aggregate surface BUR systems tend to have a longer expected service life than mineral surfaced cap sheet BUR systems because of lower membrane temperature and due to protection of the membrane by the aggregate.

Aggregate surfaced roof system coverings shall be designed and installed in accordance with the IBC Code and Table 1504.4 based on the exposure category and basic wind speed at the building site. The aggregate shall comply with the ASTM D1863 No. 6 aggregate in hurricane prone regions as defined by the IBC Section

1609.2. Aggregate is not permitted when the basic wind speed is 100 mph or greater or at airfields.

2-8.2 Modified Bitumen (MB) Membranes.

MB roofing systems have low maintenance cost, and must be considered when long service life is required. The polymers used to modify the asphalt bitumen improve the performance characteristics of the asphalt. The addition of polymers increases low temperature flexibility and high temperature stability. MB membranes are reinforced with fiberglass, polyester, or a combination of both. MB membranes must have at least two-ply or as specified by the UFGS.

2-8.2.1 Polymer Modifiers.

The two major types of bitumen modifiers used are an elastomeric Styrene Butadiene Styrene (SBS) polymer and a thermoplastic Atactic Polypropylene (APP) polymer. SBS systems are usually applied by hot mopping asphalt; however, torch varieties of SBS membranes are gaining prominence. Some SBS products are applied with cold adhesive or torching. APP systems are typically applied with propane torches, which necessitate special requirements for safe handling and storage. All torch-applied MB systems will utilize non-combustible cant strips at parapets and curbs. Only non-combustible materials shall be used for torch-applied systems, including the roof deck, parapets, and structure. If the torch method is used, specify that the roofing contractor conduct an on-site two-hour fire watch after the last torch is extinguished. Provide access to the building interior for the fire watch personnel.

2-8.2.2 MB Membrane Surfacings.

The three common types of surfacing used for the top sheet of MB systems are granulated surfaced, metal foil faced, and coated smooth surfaced.

2-8.2.2.1 Granulated Surface.

Ceramic granules reduce the temperature effect on MB systems. However, as granules are lost, degradation due to ultraviolet (UV) radiation will negatively affect performance.

Longevity of these systems on average is not as great as aggregate surfaced MB systems.

2-8.2.2.2 Metal Foil Surface.

Metal foils surfaced MB roof systems may be used to achieve solar reflectivity or to improve fire resistance.

2-8.2.2.3 Smooth Surface.

Uncoated smooth surfaced systems are not permitted. Smooth surface membranes must be factory coated for heat reflection and UV protection.

2-8.3 Ethylene Propylene Diene Monomer (EPDM) Membranes.

EPDM roof membranes provide predictable serviceability in roof systems in all climates.

The minimum sheet thickness shall be 90 mil. All lap seams shall be fabricated with 6-

in. (150 mm) seam tape and stripped-in with self-adhering, semi-cured EPDM cover strips.

\1\ /1/

2-8.3.1 Mechanically fastened EPDM Systems.

Mechanically fastened EPDM are not permitted.

2-8.3.2 Fully Adhered EPDM Systems.

Fully adhered EPDM systems do not allow billowing of the membrane and are the preferred method of EPDM installation.

2-8.3.3 Ballasted EPDM Systems.

Ballasted EPDM roof systems use larger sheets with factory made seams, which are proven superior to field seams. The downside of ballasted roof systems is the need for stone ballast or concrete pavers, and the increased difficulty in detecting sources of leaks. The ballast is relatively heavy at 10 to 12 lbs. per sf. (49 to 59 kg per sm) and may affect the structural system. All ballasted systems shall comply with ANSI/SPRI RP-4, Wind Design Standard for Ballasted Single-ply Roofing Systems.

2-8.4 Weldable Thermoplastic Membranes.

Thermoplastics are materials that soften when heated and regain their physical properties upon cooling. Weldable thermoplastic membranes are appealing as roofing systems because when the seams are properly heat welded they can exhibit seam strengths comparable to the membrane sheet. Weldable thermoplastic membranes are available in white or other light colors to reduce solar heat gains. While the material costs are higher than bituminous-based roofing, labor costs are generally lower.

Properly constructed weldable thermoplastic membrane systems may last 15 years or more. Of all weldable thermoplastics, PVC systems have the longest time in service.

TPO is addressed separately—see below.

The minimum thickness of weldable thermoplastic membranes shall be \1\ 60 mils (1.52

mm) /1/

2-8.4.1 Mechanically fastened Weldable Thermoplastic Systems.

Mechanically fastened weldable thermoplastic systems allow some billowing of the roof membrane; however, this is greatly limited by reinforcement fabrics. Cool roofs in ASHRAE Climate Zones 4-8 shall be fully adhered and not mechanically fastened.

2-8.4.2 Fully Adhered Weldable Thermoplastic Systems.

Fully adhered weldable thermoplastic systems do not allow billowing of the roof membrane and are the preferred method of installation.

2-8.5 Hot Rubberized Reinforced Fluid-applied Membranes.

Hot rubberized reinforced fluid-applied membranes are only permitted when designed and shop drawings reviewed by an RRC or a registered PE or RA that derives his or her principal income from roofing design. Further, the membrane shall be applied to a minimum 4-inch (100-mm) thick concrete surfacing.

2-8.6 Thermoplastic Polyolefin (TPO).

TPO membranes are a relatively new roof membrane in the commercial roofing market and have seen several reformulations in the past decade. They are typically white in color and, as a thermoplastic, the seams are heat welded. Since they are new, long-term performance is unknown at this time. TPO should be specified with caution and only with 72 mil (1.8 mm) minimum thickness.

Mechanically fastened systems are popular but are restricted to the ‘rhino bond’ system and are not permitted in ASHRAE zones 4-8. Fully adhered systems are recommended. A cover board shall be utilized in all systems.

As noted above, TPO shall only be allowed on roofs with an anticipated life of 10 years or less. Further, TPO shall only be used with approval from the Service-specific subject matter expert (SME).

2-9 LOW-SLOPE CONSTRUCTION DETAILS.

Use the NRCA Construction Details CD - 2010 construction details as applicable, except as noted in Table 2-1 in this UFC. For details pertaining to low-slope metal roofing, refer to Chapter 5 of this document. Design documents for individual projects must supplement these standard details with additional information related to closures, terminations, transitions, corners, lap and joint conditions, materials interface, sealant requirements, and other project specific conditions. Address all flashing requirements with a complete set of detail drawings. Minimize the use of pitch (or pourable sealer) pans.

TABLE 2-1. LOW-SLOPE ROOFING CONSTRUCTION DETAIL LIMITATIONS

NRCA Detail Comments BUR-4 For use only with concrete parapet walls where installation of a reglet and counter flashing inserted into the reglet joint is not possible.

BUR 4S For use only with concrete parapet walls where installation of a reglet and counter flashing inserted into the reglet joint is not possible.

8B Do not use.

8BS Do not use.

MB-4 For use only with concrete parapet walls where installation of a reglet and counter flashing inserted into the reglet joint is not possible.

MB-4S For use only with concrete parapet walls where installation of a reglet and counter flashing inserted into the reglet joint is not possible.

8B/8C Do not use.

8BS/8CS Do not use.

EPDM-4 For use only with concrete parapet walls where installation of a reglet and counter flashing inserted into the reglet joint is not possible.

EPDM-4S For use only with concrete parapet walls where installation of a reglet and counter flashing inserted into the reglet joint is not possible.

EPDM-5 Termination Bar holes must be slotted for expansion and contraction.

EPDM-5S Termination Bar holes must be slotted for expansion and contraction.

EPDM-8B Do not use.

EPDM-8BS Do not use.

3 For use only with concrete parapet walls where installation of a reglet and counter flashing inserted into the reglet joint is not possible.

3S For use only with concrete parapet walls where installation of a reglet and counter flashing inserted into the reglet joint is not possible.

5S Lightweight insulating concrete not applicable.

SPF-7A Do not use.

SPF-7AS Do not use.

(FB)-1 Fleece-backed membrane not applicable.

(FB)-2 Fleece-backed membrane not applicable.

(FB)-3 Fleece-backed membrane not applicable.

(FB) -4 Fleece-backed membrane not applicable.

(FB)-5 Fleece-backed membrane not applicable.

(FB)-6 Fleece-backed membrane not applicable.

Figure 9 Page 314 For use only with concrete parapet walls where installation of a reglet and counter flashing inserted into the reglet joint is not possible.

SP-4 For use only with concrete parapet walls where installation of a reglet and counter flashing inserted into the reglet joint is not possible.

SP-4S For use only with concrete parapet walls where installation of a reglet and counter flashing inserted into the reglet joint is not possible.

SP-5 Termination Bar holes must be slotted for expansion and contraction.

SP-5S Termination Bar holes must be slotted for expansion and contraction.

SP-8A Do not use.

SP-8AS Do not use.

CHAPTER 3 STEEP-SLOPE ROOFING DESIGN REQUIREMENTS

3-1 GENERAL.

Steep-slope roofs provide more efficient drainage than low-slope systems and, as a result, are less likely to leak. This chapter does not cover steep-slope metal roofing (see Chapter 5). Chapter 3 limits the applicability of certain techniques permitted by the NRCA to focus on long life cycle military requirements. Where contents of the NRCA Manual are acceptable without modification, those sections are not mentioned.

3-2 DESIGN-BUILD.

Because of the wide variety of materials available and the variation in quality…