- Assessment Tools for Accessibility
- Blast Safety of the Building Envelope
- Chemical / Biological / Radiation (CBR) Safety of the Building Envelope
- Designing Buildings to Resist Explosive Threats
- Flood Resistance of the Building Envelope
- HVAC Integration of the Building Envelope
- Indoor Air Quality and Mold Prevention of the Building Envelope
- Seismic Safety of the Building Envelope
- Sustainability of the Building Envelope
- Threat/Vulnerability Assessments and Risk Analysis
- Wind Safety of the Building Envelope
- Windows and Glazing
Building Envelope Design Guide - Exterior Doors
Last updated: 06-07-2010
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This Chapter includes entrance and exit doors, as well as industrial loading dock doors, and addresses waterproofing and durability requirements, primarily. This Chapter covers aluminum- and steel-framed doors, with or without glass panel in-fills, and frameless glass doors. It does not cover wood-framed doors. The following describes common functions served by the door types covered in this chapter:
Entrance and exit doors generally serve as building entrances for the general public or as service entrances for building operations personnel. They typically serve double-duty as emergency egress. The International Building Code (IBC), government regulations, including the Americans with Disabilities Act (ADA), and local codes govern many entrance/exit door requirements pertaining to life safety and accessibility. These requirements are beyond the scope of this chapter.
Industrial Doors provide access for material handling in buildings. Although functionally "doors", they are typically rolling or coiled gates, or sliding security grilles, that can open large apertures in a building wall to allow unloading and loading trucks that back up to an elevated dock, or to allow building access for vehicles.
The following presents brief descriptions of commonly used door types and their components:
Common door types include:
- Swing doors, generally serving Entrance/Exit functions.
- Revolving doors, generally serving Entrance/Exit functions.
- Industrial (e.g. overhead) doors, serving material handling and security functions.
Commonly used door materials include aluminum, steel, wood and glass. Doors that are integrated with commercial storefronts are typically aluminum frames with glass in-fills, or all glass. Steel-clad doors are generally utilized for service entrance/exit functions. Wood doors are most commonly employed in low density residential construction. Monumental wood or wood-and-glass doors are sometimes used in commercial or institutional buildings. Wood doors are beyond the scope of this chapter.
Industrial doors are used for material handling, not for pedestrian access. Their main function is to provide security. They are, therefore, frequently not designed for building envelope performance. Security grates or doors are typically installed over more conventional storefront systems. Typical materials for exterior applications are steel, aluminum, and stainless steel. The doors also frequently incorporate glass in-fill panels. Rolling doors typically consist of a steel frame that is anchored to the perimeter construction to resist wind and operating loads, structural guides for the door edges, and a hood that contains the rolled up "curtain" when the door is in the open position. Larger industrial doors are motorized; smaller units can be operated by manual push-up, chain hoists, or cranks. Motorized doors are often opened and closed with automatic gate operators.
Egress requirements for Entrance/Exit doors are governed by the applicable building code based on building use, occupancy load, and door type (swing, sliding or revolving). Chapter 10 of the IBC—Means of Egress—contains egress requirements, including minimum door height and width, maximum door leaf width, panic hardware, step down dimensions to the exterior, requirements for threshold geometry, door swing direction (in direction of egress travel for occupancy loads greater than 50 people or for high hazard occupancy), illumination, operating force, signage, etc. Revolving doors must fold flat in the direction of egress and have outswinging doors nearby. A further discussion of egress requirements for Entrance/Exit doors is beyond the current scope of this chapter.
The intent of accessibility regulations is to allow persons with physical disabilities to independently enter and use a building. Because non-compliant doors can present obstacles to wheelchair-bound individuals, door design must account for accessibility. Accessibility requirements for Entrance/Exit doors are governed by the applicable building code as well as federal regulations. Chapter 11 of the IBC—"Accessibility", contains requirements for number, location, and configuration of doors that comply with the ADA. For the purposes of this Chapter, discussion of accessibility is limited to the features of accessible doors namely their low threshold heights required to accommodate wheelchairs, that affect their waterproofing performance. A more detailed discussion of accessibility requirements is beyond the scope of this chapter.
Thermal performance (conduction, solar radiation, thermal break, comfort)
Doors are frequently problematic components of a building's thermal envelope. Typical issues include heat loss from air movement during operation, heat loss from air movement through the perimeter detail, and radiant heat loss through the door materials themselves. Door frames that do not incorporate adequate thermal isolation form thermal bridges that tend to lead to wintertime condensation. Overall door thermal performance is a function of the type of operation (e.g. swing, sliding, revolving), the glazing (if applicable), the frame and perimeter details, the sash and sash weatherstripping, and the door materials.
Aluminum-framed doors that are part of curtain wall or storefront assemblies sometimes have thermally-broken frames and insulating glass units, which provide improved thermal performance. See the discussions in Glazing and Curtain Walls. Opaque entrance doors or loading dock doors often have foamed-in-place insulation between their exterior and interior metal skins, which typically provides better thermal performance than insulating glass. These insulated doors must have internal stiffeners to stiffen the face skins and provide adequate structural performance.
Heat loss from air leakage is the most significant challenge to thermal performance for heavily used entrance and exit doors. Strategies to limit air loss and improve thermal performance for these doors include:
Revolving doors minimize heating and cooling losses from air movement and minimize wind effects on door operability. Since they cannot be left open, they also make mechanical loads on the building more predictable, and are therefore preferable for the building's HVAC design. In colder climates, air curtains provide a barrier of fast-moving warm air that limits penetration of cold exterior air while the door is open and are frequently used with sliding doors. The warm air may also be used to raise the surface temperature of the doors, which limits condensation. Entrance vestibules with separate inner and outer doors provide improved energy performance over a single entrance door, mainly by limiting loss of conditioned air during door operation.
When they are closed, all doors rely on weatherstripping between the operable sash and the door frame to limit air movement.
Because the irregular articulated surfaces and mounting hardware of rolling doors do not lend themselves to weatherstripping, the perimeter construction of loading dock doors is notorious for poor air penetration resistance. Because these doors are typically specified for warehouses, garages, and similar applications, thermal performance is often a secondary concern. The air penetration resistance of rolling doors can be improved by providing heavy duty weatherstripping, including vinyl or wool pile weatherstrips along the jambs, a neoprene bulb wiper strip at the front of the curtain, and a neoprene baffle at the top of the coil. These features also help with water penetration resistance; see below.
Moisture protection (water penetration, condensation resistance)
Water penetration resistance is a function of glazing details (see Glazing), frame drainage details, weatherstripping and perimeter details (head, jamb and sill flashing). See Windows for general guidelines on perimeter details of punched openings, which apply to doors as well.
Outswinging doors generally resist water and air penetration better than inswinging doors, because the upturned leg of the threshold is on the interior side of the door and also because exterior positive wind pressures tend to compress the door leaf against the weatherstripping.
Entrances/exits are often recessed from the plane of the exterior wall to avoid opening out into a public way, but also to provide shelter from wind and weather. Entrance vestibules with inner and outer doors provide improved moisture protection performance over a single entrance door. The vestibule itself can be designed to tolerate water by providing water resistant finishes (e.g. concrete or tile), a waterproofing membrane beneath the finishes, and a floor drain. Where a full vestibule is not feasible, an overhanging awning provides some protection from the rain.
Door thresholds frequently leak. To collect this water penetration and drain it back to the exterior, sill flashings with a panned up interior leg and end dams are required. The sill flashing, if properly designed and installed also serves to collect and expel water that is collected by the jamb flashing, which has to shingle into the sill flashing. The waterproofing performance of door thresholds can be improved by increasing the threshold height, but threshold height is frequently limited by ADA requirements.
Visual (Daylighting, Aesthetics)
Entrances and Exits frequently include glazed doors. Key visual features of glazed doors include glazing appearance (see Glazing) and frame sightlines. Frameless (all glass) doors maximize the glass area, generally at a cost premium.
The acoustic performance of doors is primarily a function of the air leakage around the door, the materials (see Glazing for a discussion of strategies to limit sound transmission for insulating glazing, which is applicable to doors with large vision lites or all-glass doors). Sound attenuation through doors can be improved by increasing the mass of the frames and sash, improving the airtightness of the glazing, sash-to-frame and frame-to-perimeter joints, and placing sound-absorptive materials at the perimeter of the doors.
Revolving doors and entrance vestibules with inner and outer doors provide improved acoustic performance by limiting air leakage during door operation.
Glass in doors should be safety glazing; see the discussion in Glazing.
Motorized rolling doors and security grates must have a safety system that reverses the direction of door travel when they encounter an obstruction. This feature is intended to prevent serious injuries from pinching or crushing. Obstruction-sensing devices include pressure sensors in the leading edge of the door, or photo eye sensors. Motorized revolving doors require similar obstruction-sensing devices.
Operating and security hardware and access control are key design features for doors. Important design issues include:
- Panic hardware for egress doors
- Electronic access control systems
- Automatic operators for security and accessibility
- Locking hardware
This subject is beyond the scope of this chapter.
Water leakage through or around doors can contribute to indoor air quality (IAQ) problems by supplying moisture for mold growth. This leakage can often remain concealed within the wall system or flooring and not become evident until concealed wall components experience significant deterioration and mold growth. See the section on moisture protection (Section 3.4 above) for a discussion.
Revolving doors and double-wall vestibules limit ingress of airborne pollutants and dust particles by reducing air flow through doors. The U.S. Green Building Council's LEED Rating System includes credits for Indoor Chemical and Pollutant Source Control. To obtain a portion of the credits, a project must have "permanent entryway systems (grills, grates, etc.) to capture dirt, particulates, etc. from entering the building at all high volume entryways." The grills and walk-off mats necessary for this system are often housed in a vestibule.
Wear and Tear: Since they are used intensively, doors will typically have a shorter service life and higher maintenance requirements than other building envelope components such as curtain walls and windows. Entrance doors must be able to handle the ingress/egress demands of the building. Intensity of use is measured by cycles of operation. ANSI A250.8—Recommended Specifications for Standard Steel Doors and Frames, and ANSI A250.4—Test Procedure and Acceptance Criteria for Physical Endurance for Steel Doors, Frames, Frame Anchors and Hardware Reinforcings, establish the following Performance Classifications and swing-and-latch test cycles:
- Level C, Standard Duty — 250,000 cycles
- Level B, Heavy Duty — 500,000 cycles
- Level A, Extra Heavy Duty — 1,000,000 cycles
Life cycle operation durability is a function of door leaf (i.e. sash) construction (e.g., size and thickness of aluminum frames, thickness of steel sheet facings), frame construction, durability of hardware, etc.
Corrosion Resistance: Aluminum frames are inherently corrosion resistant in many environments if anodized and properly sealed or if coated with baked-on fluoropolymer paint. Aluminum frames are subject to accelerated deterioration of the coating and corrosion of aluminum in severe (industrial, coastal) environments, and galvanic corrosion from contact with dissimilar metals. Doors and storefronts are frequently exposed to de-icing salts that degrade frame and sash finishes and base materials.
Steel doors depend on an applied coating for corrosion resistance. Coating systems that include a galvanic protection primer (e.g. zinc-rich paint, hot dipped galvanizing) in combination with a barrier coat of paint provide significantly better corrosion resistance than coating systems that rely on a barrier coat of paint alone.
Doors and perimeter sealants require maintenance to maximize their service lives. Perimeter sealants, properly designed and installed with high quality material, have a typical service life of 10 to 15 years although some breaches are likely from day one. Perimeter sealants require careful surface preparation to minimize breaches and maximize surface bond.
Ungalvanized steel frames require frequent inspection and maintenance of coatings. Steel frames that have galvanic protection under the paint can generally tolerate longer intervals between paint maintenance than those without galvanic protection. Hollow steel doors with direct exposure to the weather often rust prematurely, even if they are galvanized and frequently repainted, because water inevitably finds its way between the exterior and interior steel sheets, causing the doors to rust from the inside out.
Aluminum frames are painted or anodized. Factory applied fluoropolymer thermoset coatings have good resistance to environmental degradation and require only periodic cleaning. Recoating with an air-dry fluoropolymer coating is possible but requires special surface preparation and is not as durable as the baked-on original coating.
Anodized aluminum frames cannot be "re-anodized" in place, but can be cleaned, restored visually, and protected by proprietary clear coatings that require frequent re-application.
Door hardware requires frequent inspection, adjustment, and lubrication.
The best strategy for sustainability of doors is to employ good design practices to ensure the durability (maximum service life) of the installation.
Aluminum and steel frames can be recycled at the end of their service lives. Salvage and demolition contractors generally require a minimum of 1,000 sq ft or more of curtain wall/storefront to make material recycling economical (smaller amounts are generally disposed as general trash). Recycling is less economical if the aluminum is contaminated with sealants, glass fragments, etc., as salvage companies pay considerably less for the material.
Aluminum window and door frames generally do not incorporate post-consumer recycled material because manufacturers have reported problems with the appearance and durability of anodized coatings. Manufacturers report fewer problems with paint coatings. Most production facilities are set up to recycle their own aluminum scrap (e.g. cuttings, rejected frame sections).
Energy efficiency is an important factor when designing for sustainability. Vestibules and revolving doors improve energy performance.
Establish System Track Record
Select a door with a demonstrated track record in similar applications and exposures. Verifying track records may require significant research by the designer. ASTM E1825 provides guidance.
Review laboratory test results of door systems for air, water, and structural resistance, heat transmission, condensation resistance, sound transmission, and operability. Verify that tests pertain to the specific door under consideration and not a version of the door with the same product name but of different construction.
Designing for Waterproofing Performance
Designers can provide the following to improve the waterproofing performance of entrance doors:
- Vestibules or awnings shield the doors from wind-driven rain.
- Trench drains along the door sill, and paving surfaces that slope away from the door, reduce ponded water against the sill.
- Waterproofing membranes that extend under the entire vestibule, and shed water toward the exterior (e.g. extensions of the plaza waterproofing) can collect and discharge water that penetrates past the doors. The waterproofing membrane and interior flooring must be carefully detailed to prevent water damage to interior floor finishes from water collected on the membrane, for example, water from the exterior wicking upward in a sand setting bed used to support stone flooring.
- Continuous perimeter flashings that collect and expel water that penetrates through or around the frames are vastly more effective than relying solely on perimeter seals or weatherstripping to keep water out. See Windows for guidance on head, jamb and sill flashings that are applicable to doors. These details must be adjusted to reflect the door threshold geometry and fastening requirements. The horizontal portion of the sill flashing must not be penetrated with threshold fasteners. Instead, where attachment of the threshold is required, an attachment angle should be provided inboard of the threshold and fastened through the upturned leg of the sill flashing into the back of the threshold. The threshold should then be recessed flush with the finish floor to avoid a tripping hazard and to protect the inboard upturned leg of the flashing. Where the recessed attachment angle and flashing cannot be accommodated, the sill flashing should have a small upturned leg concealed within the threshold, but inboard of the innermost weatherstripping and fasteners. The sill flashing must extend beyond the jamb to collect leakage from the jamb flashing.
- Raised door sills and thresholds elevated above the sidewalk to shed water provide for more reliable waterproofing details at entrance doors but are almost always at odds with ADA requirements; see 3.4 above for door sill flashing recommendations. Where such limitations do not exist, a minimum threshold height of 6 in. (more if the door sill will be subject to drifted snow) is advisable. Entrance doors at grade will almost always have a flush sill to satisfy ADA regulations, reduce tripping hazards, and to facilitate deliveries. Consider alternative designs utilizing ramps and platforms to comply with ADA requirements while allowing favorable curb, threshold and flashing heights.
- Out-swing doors: Outswinging doors generally resist water and air penetration better than inswinging doors, because the upturned leg of the threshold is on the interior side of the door and also because exterior positive wind pressures tend to compress the door leaf against the weatherstripping.
- Weatherstripping alone, even double weatherstripping, is typically not sufficient protection from wind-driven rain in high exposure locations.
- Roofing: Vestibules projecting beyond the face of a building require a competent roof. See Roofing Design for design advice on roofing systems.
Designing for Condensation Resistance
Use thermally broken aluminum frames for improved condensation resistance. AAMA's Window Selection Guide provides guidance on glazed door selection for condensation resistance. Establish the required Condensation Resistance Factor (CRF) based on anticipated interior humidity and local climate data and select a door with an appropriate CRF. Designers should be aware that, similar to windows, the CRF is a weighted average for a door assembly. The CRF does not give information about door cold spots that could result in local condensation. When evaluating a potential door system, carefully review the data contained in the CRF test report for the specific product. The report will contain a listing of interior surface temperatures and locations on both the frame and glazing. In many cases, comparing surface temperature data to the expected interior dewpoint temperature can provide a better measure of condensation resistance than the CRF alone. Projects for which condensation control is a critical concern, such as high humidity buildings, require project-specific thermal modeling. Careful analysis and modeling of interior conditions is required to accurately predict condensation on the glass and frame. Doors that are set well away from perimeter heating elements will have air temperatures along their interior surface that are significantly lower than the design wintertime interior temperatures. Thermal modeling of the building interior using Computational Fluid Dynamics (CFD) software can help establish a reasonable estimate for air temperatures at the inside surfaces of the glass and frame. These interior air temperatures are inputs for window thermal modeling software such as THERM.
Consider frame geometry for thermally conductive frame materials (aluminum, steel). Maximize the mass of framing exposed to the interior to improve condensation resistance.
Refer to AAMA 1503 Voluntary Test Method for Thermal Transmittance and Condensation Resistance of Windows, Doors, and Glazed Wall Sections for descriptions of test method, parameters and equipment for determining U values and CRF's for door products.
Vestibules and air curtains reduce heat loss at inner doors and creation of cold spots. Both reduce the potential for condensation problems.
Designing for Finish Durability
Aluminum: Class I anodic coatings (AAMA 611, supersedes AAMA 606, 607 and 608) and high performance factory applied fluoropolymer thermoset coatings (AAMA 2604, supersedes AAMA 605) have good resistance to environmental degradation.
Steel: The thin steel used in conventional steel-clad doors with steel frames makes galvanized coating as a base for paint a must.
All frame materials: Shielding doors from the weather by recessing them back from the exterior face of the wall and/or providing roof overhangs or projecting head flashings or drips is an effective strategy for minimizing water penetration and maximizing the service life of door finishes.
This section to be developed
Loading Dock Doors
Logistical and Construction Administration Issues
The service life of even the most durable door is likely to be shorter than that of the surrounding exterior wall construction. Therefore, the design of the door and perimeter construction should permit door removal and replacement without removing adjacent wall components that will remain.
The service life expectancy of components that are mated with the door into an assembly should match or exceed the service life expectancy of the door itself. Require durable flashing materials, non-corroding attachment hardware and fasteners, and moisture resistant materials in regions subject to wetting.
Laboratory testing: For projects with custom doors, require laboratory testing of mock-up door prior to production of doors for the project. Have a building technology specialist present to document mock-up door construction.
Field Mock-up: For all doors, stock or custom, require construction and testing of a field mock-up representative of the wall/door assembly for testing and evaluation of constructability, sequencing of trades and integration with adjacent wall elements.
Testing of production doors: Require the field testing of production doors for quality assurance of door fabrication and installation. Require multiple tests early in the construction phase to catch problems early.
Shop drawing coordination: Require door installation shop drawings showing all adjacent construction and related work, including flashings, door attachments, interior finishes, and indicating sequencing of the work. Shop drawings should show isometric or axiometric details of corner assemblies.
The following details can be downloaded in DWG format or viewed online in DWF™ (Design Web Format™) or Adobe Acrobat PDF by clicking on the appropriate format to the right of the drawing title. Download Autodesk® DWF Viewer. Download Adobe Reader.
This detail shows the construction of a waterproofing membrane under a vestibule.
- The exterior waterproofing membrane continues into the vestibule and is turned up against a curb. The membrane and finish floor slope to the exterior.
- The exterior and interior doors have double sweep gaskets to improve air and water penetration resistance.
This detail shows the construction of a waterproofing membrane under a revolving door.
- The exterior waterproofing membrane continues into the vestibule and is turned up against a curb. The membrane and finish floor slope to the exterior.
- The revolving door frame is mounted to a curb to improve its water penetration resistance.
- The revolving door leaves have sweep gaskets to improve air and water penetration resistance.
This detail shows the construction of a sill flashing under a door sill. The sill is mounted flush without a raised curb.
- The door sill has a concealed sill flashing with an upturned end-dam. The flashing has to extend beyond the jamb and is integrated with the jamb flashing; see Detail 3.5-4.
- The sill flashing shingles over the plaza or foundation wall waterproofing membrane below.
This detail shows the construction of a door jamb.
- The door has a continuous jamb flashing that is integrated with the wall waterproofing. The flashing is sealed to the door frame to provide a continuous air barrier.
- The jamb flashing shingles into the sill flashing; see Detail 3.5-3.
This detail shows the construction of a door head flashing.
- The door has a continuous head flashing that is integrated with the wall waterproofing. The flashing extends beyond the face of the wall, is sloped toward the exterior, and has a drip.
Biometric Access Control Systems include devices that verify a person's identity based on unique personal biometric characteristics, such as fingerprints, before allowing access to high-security areas. Biometric access control systems have been in use for years, but have seen increased use and development recently because of homeland security concerns.
Blast-Resistant Door and Window Assemblies are discussed in the Resource Page Blast Safety.
Energy Star is a federal initiative to help consumers identify energy efficient products, including doors and windows. Available energy star ratings include residential products only, but the program is expanding to commercial buildings.
Relevant Codes and Standards
General Building Code Requirements and Safety
- International Building Code (IBC), Chapters 10 and 11
- UL Bulletin 325 "Safety for Door, Drapery, Gate, Louver, and Window Operators and Systems"
Design and Selection
- AAMA/WDMA/CSA 101/I.S.2/A440-05—Standard/Specification for Windows, Doors and Unit Skylights (updated)
- ANSI A250.4 for Steel Doors and Frames
- ANSI A250.8 for Steel Doors and Frames
- AAMA 1503, Voluntary Standards for Thermal Transmittance and Performance
- AAMA 1504, Voluntary Standards for Thermal Transmittance and Performance
- AAMA 1505, Voluntary Test Methods for Thermal Performance of Fenestration Products with Multiple Glazing Options
Water Penetration Resistance
- AAMA 609—Cleaning and Maintenance Guide
- AAMA 610—Cleaning and Maintenance Guide
- AAMA 611—Voluntary Specification for Anodized Architectural Aluminum
High Performance Organic Coatings
- AAMA 2604—Voluntary Specification for High Performance Organic Coatings on Aluminum Extrusions and Panels
Products and Systems
Section 07 92 00: Joint Sealants, See appropriate sections under applicable guide specifications: Unified Facility Guide Specifications (UFGS), VA Guide Specifications (UFGS), DRAFT Federal Guide for Green Construction Specifications, MasterSpec®
- American Architectural Manufacturers Association, information on aluminum and wood doors.
- Steel Door Institute, information on steel-clad doors.
- Door and Access Systems Manufacturers Association International, includes information on industrial and loading dock doors, standards pertaining to rolling door performance, and technical data sheets that address installation and design advice.
- Cornell Iron Works, rolling door specialists, includes a good terminology section on industrial and loading dock doors.