Author Archives: Molly

Glazed natural ventilators now available in North America

Firelight

The Bilco Company’s Colt’s Firelight, a glazed, natural ventilator, installs easily in a glass atrium or directly onto the roof of a building. This dual-purpose product provides buildings with both day-to-day ventilation and smoke control to aid building evacuation in the event of a fire.

Firelight is available in single- or double-leaf design and with control options for automated climate control in a building.

Firelight glazed natural ventilators are designed for high aerodynamic, acoustic and thermal performance. The product provides ventilation for most kinds of industrial and commercial buildings, and is particularly suited for installation into atriums and glazing systems.

The Firelight is available in several standard designs and can be specified with a powder coat finish to complement or blend into any roof exterior. The product features a thermally broken design to minimize heat loss for reduced carbon emissions into the environment and maximum energy efficiency.

In addition to the standard manual operation, the Firelight can be specified for electric or pneumatic operation and set to open and close as required for proper mixed-mode ventilation. The systems can provide an energy-efficient solution to maintain a good internal climate, low humidity levels, and low running and maintenance costs. In addition to climate control, the Firelight control options allow the product to be used as a smoke control system in an emergency situation.

Firelight glazed natural ventilators are custom-fabricated to meet virtually any size or building ventilation requirements. Products feature aluminum construction and are available with a number of cover and finish options.

For more information, visit www.bilco-colt.com.

Wind Load and Air Barrier Performance Levels: ABAA-evaluated Air Barrier Assemblies

Even though some codes include air barrier assembly as a compliance option, the default compliance path for air leakage control tends to be through air barrier materials. For many years, practitioners relied on air barrier materials properties, while the performance of installed air barriers was largely untested. While testing air barrier assemblies can offer information on performance of installed air barriers, few manufacturers engaged in this because it was not required by code.

In 2009, the Air Barrier Association of America (ABAA) developed an evaluation process to establish performance of installed air barriers. To

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be listed by ABAA, manufacturers were required to submit third-party test reports for air barrier materials and assemblies, as well as demonstrate compliance with current standards. Air barrier assemblies are required to be tested in accordance with ASTM E2357, Standard Test Method for Determining Air Leakage of Air Barrier Assemblies. The ABAA website currently lists air barriers that have completed the evaluation process to date.*

The air barrier assemblies listed on the site do not include water resistance testing, which is not required by ASTM E2357. This is a major limitation of the standard, since air barriers commonly serve as water-resistant barriers (WRBs) as well. A separate section lists those materials meeting WRB acceptance criteria (i.e. International Code Council Evaluation Service [ICC-ES] Acceptance Criteria [AC] 38, Water-resistive Barriers), but that have not been tested in wall assemblies.** Very few manufacturers integrate the water infiltration resistance testing of ASTM E331, Standard Test Method for Water Penetration of Exterior Windows, Skylights, Doors, and Curtain Walls by Uniform Static Air Pressure Difference, with ASTM E2357’s air barrier assembly testing, which is very important for assessing performance of installed air and water barriers.

Even though the importance of air barrier assembly testing has been recognized before the ABAA initiative, the association’s evaluation process was critical in implementing uniform performance criteria across the industry.

* Visit www.airbarrier.org/materials/assemblies_e.php. This air barrier section does not include water resistance testing (which is not required by ASTM E2357), but WRBs can be found at www.airbarrier.org/resistive/index_e.php.
** Visit www.airbarrier.org/resistive/index_e.php.
† See co-author Spinu’s previous article for The Construction Specifier, “Testing Mechanically Fastened Air Barrier Systems,” which appeared in the December 2009 issue.

To read the full article, click here.

Wind Load and Air Barrier Performance Levels

Photo courtesy DuPont Building Knowledge Center

Photo courtesy DuPont Building Knowledge Center

by Maria Spinu, PhD, LEED AP, Ben Meyer, RA, LEED AP, and Andrew Miles

Continuous air barriers have become mandatory for the building envelope, with energy codes recognizing the importance of air leakage control. However, simple inclusion of an air barrier requirement does not guarantee the desired performance in the field. These systems must be properly installed, meet the building envelope structural wind loads, and maintain their function over time.

There are two accepted performance levels for commercial air barrier systems, determined by the structural design parameters for the building envelope:

  • ASTM E1677, Standard Specification for Air Barrier Material or System for Low-rise Framed Building Walls, applicable to envelope design specifications of up to 105-km/h (65-mph) equivalent structural loads; and
  • ASTM 2357, Standard Test Method for Determining Air Leakage of Air Barrier Assemblies, for buildings designed to withstand structural loads beyond that level.

This article describes the air barrier performance requirements for the desired wind load design specifications. The performance level is not determined by the type of air barrier material, but by the installation details. Examples of how these details can impact the performance level for a given air barrier system will be provided, with special emphasis on mechanically fastened air barriers.

Summary comparison between ASTM E1677 and ASTM E2357 wall assembly testing.

Summary comparison between ASTM E1677 and ASTM E2357 wall assembly testing.

Air leakage control and air barrier materials
Air leakage control is achieved through a continuous air barrier. Any material with an air permeance less than 0.02 L/(s • m2) @ 75 Pa pressure differential (0.004 cfm/sf @ 0.3 in. w.c. or 1.56 psf pressure differential), when tested in accordance with ASTM E 2178, Standard Test Method for Air Permeance of Building Materials, qualifies as an air barrier. Even though many common building products are air barrier materials (e.g. metal sheets, glass, oriented strandboard [OSB], and gypsum board), a continuous air barrier requires many compatible components to achieve a plane of airtightness. In practice, most air barrier materials are specifically designed membranes effectively integrated into a continuous air barrier system.

Testing of walls with mechanically fastened air barrier systems. Image courtesy DuPont and ATICommon air barrier materials include mechanically fastened (i.e. building wraps), fluid-applied, and self-adhered membranes. The choice depends on many factors, such as the substrate, desired performance level, installed cost, personal preference, local practices, and regional availability.

For example, in framed construction where air barriers are applied over exterior sheathing, building wraps are the most cost-effective. For masonry or concrete backup walls, fluid-applied membranes are the common choice. Self-adhered membranes can be used with either substrate, but most are vapor-impermeable and their use should be limited to specific climates and wall design options.

In the case of vapor-impermeable air barriers, the membrane plays a dual role: air and vapor barrier. While air barriers could be installed anywhere in the building envelope, vapor barrier location and use is climate- and design-specific. For example, vapor barriers are required only in cold climates, and must be installed at the ‘warm in winter’ side of the envelope. In warm-humid climates, a vapor barrier could still be acceptable to the outside of the envelope (where the air barrier is generally installed) when design options for drying pathways are available—such as when vapor-permeable materials must be used at least in one direction (in this example, everything to the inboard from vapor barrier must be vapor-permeable). Exulation wall design (i.e. exterior insulation only, no insulation in the stud cavity) can also use vapor-impermeable air barriers. Building physics must always be considered when an unintended vapor barrier is used in a wall assembly.

There are four essential performance requirements for air barriers:

  • air infiltration resistance;
  • continuity;
  • structural integrity; and
  • durability.1

Another critical property is vapor permeability, which could impact moisture management in wall assemblies. However, the codes do not specify the air barriers’ vapor permeance—the decision is left to the building envelope designer.2

CS_July_2014.inddAir infiltration resistance is an inherent material property for air barrier materials. Other requirements depend not only on material properties, but also on the performance of the installed system determined by the integration of air barrier components into a continuous system, as well as the durability under use conditions. In addition to the primary air barrier membrane, an air barrier system includes installation and continuity accessories, such as primers, mechanical fasteners, seam tapes, flashing, adhesives, and sealants.

This article mainly focuses on structural integrity requirement, which is the ability of an air barrier system to withstand wind loads experienced during the building’s use after construction is complete. There are two accepted performance levels based on building envelope design parameters with regard to wind loads and wind-driven rain. To establish the performance level of an installed air barrier system, air barrier wall assemblies must be tested in accordance with the respective ASTM standards.

Installed air barrier performance and wall assembly testing
Testing is essential for demonstrating performance of installed air barrier assemblies. This process is critical for developing robust installation guidelines for achieving air barrier performance levels consistent with structural design specifications.

As mentioned, ASTM E1677-11 applies to air barrier performance levels for building envelope design requiring up to 105-km/h (65-mph) equivalent structural loads, and up to 24-km/h (15-mph) equivalent wind-driven rain water infiltration resistance. This level is generally adequate for buildings of up to four or five stories, but higher performance is typically required on some low-rise structures like medical facilities and military buildings. ASTM E2357-11, on the other hand, applies to air barrier performance levels for building envelope design structural loads beyond this—such a performance level is generally necessary for buildings taller than five stories.

CS_July_2014.inddBoth test methods are performed on 2.4 x 2.4-m (8 x 8-ft) wall assemblies. ASTM E1677 requires testing of a single, opaque wall assembly (i.e. no penetrations except for the fasteners), while ASTM E2357 involves two specimen—an opaque wall and a penetrated wall that includes standard penetrations such as window openings, external junction boxes, and galvanized duct.

Both test methods require pressurization and depressurization testing, but use different pressure loads and schedules. The major differences between the two test methods are summarized in Figure 1, and consist of the pressure loads, schedule, and requirement for water infiltration resistance testing.

As shown, ASTM E1677 requires five test pressures:

  • ± 75-Pa pressure differential (1.56 psf, 25 mph);
  • two pressures below 75 Pa; and
  • two pressures above 75 Pa.
CS_July_2014.indd

Examples of window flashing for ASTM E2357 performance level.

The pressure loading schedule includes sustained loads of up to ±500 Pa (10.4 psf, 65 mph). This standard requires testing for water infiltration resistance per ASTM E331, Standard Test Method for Water Penetration of Exterior Windows, Skylights, Doors, and Curtain Walls by Uniform Static Air Pressure Difference. Air barriers or air retarders (as they are referred to in ASTM E 331) are classified as either Type I or Type II. Type I air barriers, which can also perform as water-resistive barriers (WRBs), must exhibit no water penetration when tested at 27 Pa (11 in. water pressure difference)—equivalent wind speed of approximately 24 km/h (15 mph)—during a 15-minute test period. Type II air barriers are not required to be tested in accordance with ASTM E 331.

ASTM E2357 requires a minimum of seven test pressures, from ±25 Pa (0.56 psf, 15 mph) to ±300 Pa (6.24 psf, 50 mph). The pressure loading schedule includes sustained, cyclic, and gust winds up to ±160-km/h (100-mph) equivalent wind speed. This standard does not require ASTM E331 testing for water infiltration resistance, which is a significant limitation since many air barriers are commonly required to also perform the WRB function and are exposed to pressure loads above 105-km/h (65-mph) wind.3

A building wrap air and water barrier system is installed over the exterior sheathing, prior to the installation of metal panels. Proper installation is critical for meeting the building envelope structural wind loads and maintaining the air barrier continuity over time.

A building wrap air and water barrier system is installed over the exterior sheathing, prior to the installation of metal panels. Proper installation is critical for meeting the building envelope structural wind loads and maintaining the air barrier continuity over time.

Air leakage results are reported at 75 Pa for both methods. Current codes require the average air leakage rate for air barrier assemblies must not exceed 0.2 L/(s•m2) @ 75 Pa pressure differential (0.04 cfm/sf under a pressure differential of 0.3 in. w.g. or 1.57 psf) when tested in accordance with ASTM E2357 or ASTM E1677.

Since a continuous air barrier experiences both positive and negative pressures during its use, it is important assemblies be tested under both positive and negative pressures. The negative load (under suction) is typically the most severe, as it tries to pull the air barrier off the wall. Different air barrier types have different susceptibility to negative pressure loads.4

For fluid-applied air barriers, wind loads are transferred to the substrate underneath. When the substrate is masonry or concrete, a fully adhered fluid-applied air barrier has excellent structural performance under suction, as the pressure it typically takes to separate it from the substrate far exceeds the actual pressure it must withstand.

However, for framed wall construction, the structural performance of fully adhered fluid-applied air barriers under negative wind loads depends on how well the sheathing is fastened to the building structure. When the exterior sheathing is not installed to withstand the design wind loads, this could reduce the air barrier system’s structural performance. In this case, the typical mode of failure for fluid-applied air barrier is the sheathing pulling over the screws.

CS_July_2014.inddIn comparison, when building wraps are installed over exterior sheathing, the air barrier membrane is supporting the entire load. Consequently, this type of air barrier is more susceptible to wind. The suction forces are transferred through the air barrier membrane to the mechanical fasteners, and then back to the structural supports (i.e. steel or wood studs). As a result, for a mechanically fastened air barrier, the wind load performance is determined by the type of fasteners and the fastener schedule.

The photos in Figure 2 show an example of high-pressure performance testing of commercial building wraps and exemplify the extreme forces experienced by the air barrier wall assemblies under negative pressure loads. The steel studs actually buckle under the pressure differentials used for high performance testing of building wraps (left), but a properly fastened building wrap withstands this pressure and maintains the system’s structural integrity (right).5

These pictures demonstrate the importance of proper fastening of building wraps to withstand high suction loads and maintain the air barrier structural integrity during use. A common mistake with building wraps installation is use of staples for fastening the building wrap into the exterior sheathing (a practice often employed for WRBs in residential construction), rather than employing recommended screws with washers to fasten the membrane into the structural members (wood or steel studs).

Building wrap manufacturers usually provide guidelines on the type of fasteners and the fastening schedule recommended for meeting the desired performance level. Figure 3 provides an example of fastening type and schedule guidelines and the maximum wind loads allowable.

Alternate fasteners are also allowed, when applicable. Examples include standard brick tie base plates and metal plates, metal channels, horizontal z-girts, and wood furring strips mounted vertically. They can be used in conjunction with the manufacturer-recommended fasteners to meet and/or satisfy the desired design performance.

In addition to fastener selection and spacing, other installation details are critical when designing for a specific performance level. Some building wrap manufacturers provide different installation details for ASTM E1677 and ASTM E2357. These include details on sealing of penetrations, transitions, and interfaces. For example, no additional fastener sealing is necessary for building envelope design requiring up to 105-km/h (65-mph) equivalent structural loads (i.e. ASTM E1677), when recommended fasteners and schedules are used. However, if higher air infiltration resistance is desired (i.e. ASTM E2357), self-adhered flashing must be used under the fasteners.

Figure 4 shows examples of alternate fasteners, as well as the use of self-adhered flashing under the fasteners for ASTM E2357 performance level. The same recommendations are also for fluid-applied membrane fasteners.

A mechanically-fastened air and water barrier system is installed over the exterior sheathing. Fluid applied air barrier was also used for concrete masonry unit (CMU) portions of this project (not visible in the picture). Proper integration between the two air barriers used for CMU and gypsum-covered metal stud walls was critical for continuity and structural integrity.

A mechanically-fastened air and water barrier system is installed over the exterior sheathing. Fluid applied air barrier was also used for  concrete masonry unit (CMU) portions of this
project (not visible in the picture). Proper integration between the two air barriers used for
CMU and gypsum-covered metal stud walls was critical for continuity and structural integrity.

Among the most critical details determining the air barrier structural performance level are windows and doors integration into the continuous system. Most manufacturers provide step-by-step window installation guidelines. Changes in the provider’s detailing and sequencing could change the performance level (i.e. ASTM E1677 or ASTM E2357). Figures 5 and 6 show examples of specific details for achieving the desired wind load design specifications.

The detail in Figure 5 shows how the window rough openings are treated with self-adhered flashing, for the high-performance level required by ASTM E2357. For example, when the building has non-flanged, storefront, and/or curtain wall windows, the air barrier membrane is typically cut flush with the edge or the rough opening. Then, the self-adhered flashing is installed to protect the rough opening and provide a positive termination of the air barrier membrane. The pictures on the right show examples of high-performance flashing for non-flanged and/or curtain wall windows that may be bumped out from the wall plane.

Figure 6 shows an example of window flashing for ASTM E1677 performance level. The picture captures the alternate head detail, which is generally allowed for building structures with building envelope design requirements not exceeding ASTM E1677. After the air and water barrier is wrapped into the window rough opening, a top hat is created with sealant to divert water away from the window opening (if the air barrier is also intended to serve as the WRB). WRB cut pieces are then installed (I) by wrapping in and around the studs at the jamb and the head, and stapling to inside framing to secure (A). The next steps include (II): (A) apply a continuous sealant bead along jambs and head, (B) install flanged window, (C) install jamb flashing, and (D) install head flashing.

A properly installed building wrap air and water barrier system is the most cost-effective option for this building with sheathing substrate and multi-story curtain wall consisting of brick and solid-surface cladding panels.

A properly installed building wrap air and water barrier system is the most cost-effective
option for this building with sheathing substrate and multi-story curtain wall consisting
of brick and solid-surface cladding panels.

The recommended installation guidelines are based on many wall assembly tests, and changing the installation details in the field could affect the performance level for the installed air barrier assembly. Engaging the air barrier manufacturers in early design stages is critical to understanding the installation details requirement and the optimal installation sequence to achieve the desired performance level. Additionally, it helps avoid unnecessary delays during the construction phase.

The difference between the two performance levels for air barriers is not always understood by industry professionals and installers, and not clearly stated by codes. For example, American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) 90.1-2013, Energy Standard for Buildings Except Low-rise Residential Buildings, Section 5.4.3.1.3.b, defines code-compliant air barrier assemblies as:

Assemblies of materials and components (sealants, tapes, etc.) that have an average air leakage not to exceed 0.04 cfm/sf under a pressure differential of 0.3 in. w.g. (1.57 psf) when tested in accordance with ASTME 2357, ASTM E1677.

As evident from this article, performance levels for ASTM E1677 and ASTM E2357 are not equivalent—nevertheless, ASHRAE 90.1-2013 provides the two options as equals. It is little wonder there is confusion in the industry, and the potential impact of changes to the manufacturer’s installation guidelines is not always appreciated.

A building wrap air and water barrier system is installed over the exterior sheathing, exterior insulation is installed over the air barrier, and exterior cladding (brick, metal panels, and solid surfacing) are installed to the outside.

A building wrap air and water barrier system is installed over the exterior sheathing, exterior insulation is installed over the air barrier, and exterior cladding (brick, metal panels, and solid surfacing) are installed to the outside.

Fortunately, Air Barrier Association of America (ABAA) recently introduced an evaluation process for air barriers, in order to apply consistent standards across the industry. On its website, the group lists the air barriers that have been evaluated and demonstrated to meet ASTM E2357 performance level. (For more, see “ABAA-evaluated Air Barrier Assemblies.”)

Current limitations of air barrier standards
Code requirements on air leakage control have led to a large increase in the number of materials claiming to perform as air barriers. The challenge with some airtight materials is in achieving a continuous and durable air barrier system. For example, many materials designed to perform other functions (e.g. thermal insulation or exterior sheathing) that are also resistant to air infiltration have been promoted as air barriers. While such products are adequate air barrier ‘materials,’ the long term continuity and durability of these air barriers as ‘systems’ is still an open question.

Some such materials have passed the current air infiltration resistance requirements for ‘as-installed’ air barrier assemblies per ASTM E2357 and are listed at the ABAA website. However, these systems may fall short of long-term durability under the use conditions. Additional testing, such as thermal cycling and water resistance, would be necessary to assess the long-term durability of these systems. This discussion is beyond the scope of this paper, but it should be of concern to the industry.

Conclusion
Building energy codes mandate a continuous air barrier for leakage control. The air barrier system must withstand the conditions a building is exposed to during its use. There are two acceptable performance levels for air barrier wall assemblies—ASTM E1677 and ASTM E2357—that are determined by the structural design parameters for the building envelope. Some air barrier manufacturers have developed two-tier installation guidelines for the desired level, and altering the guidelines could change the performance.

A fl uid-applied air and water barrier system is ideal for this building, which consists of multiple substrates and exterior claddings. The air barrier was installed over CMUs and gypsum board sheathing substrates; the multi-story curtain wall consisted of cut limestone on the fi rst fl oor, brick veneer on the upper fl oors, cast stone trim work, and perforated metal panels.

A fluid-applied air and water barrier system is ideal for this building, which consists of multiple substrates and exterior claddings. The air barrier was installed over CMUs and gypsum board sheathing substrates; the multi-story curtain wall consisted of cut limestone on the first floor, brick veneer on the upper floors, cast stone trim work, and perforated metal panels.

A major limitation of ASTM E2357 is the lack of water infiltration resistance requirement. Very few manufacturers integrate testing for ASTM E2357 air infiltration resistance with ASTM E331 water infiltration resistance of installed wall assemblies.

Current test methods are effective in measuring performance of newly installed air barrier assemblies under pressure differentials experienced by above-grade exterior walls and represent a huge step forward from relying solely on materials properties. However, current standards do not provide information about the long-term performance under field use conditions experienced by the buildings, which include seasonal and daily temperature variations.

The air barrier system performance is only as good as the weakest link, and differential expansion and contraction of multicomponent air barrier systems can compromise its continuity. Integration of rigorous structural integrity testing of air barrier wall assemblies with thermal cycling and water infiltration resistance will provide valuable information on the long-term durability of these systems.

Notes
1 These requirements have been described in various articles, including 2006’s “Air Barriers: Walls Meet Roofs,” by Wagdy Anis and William Waterston (www.shepleybulfinch.com/pdf/Air_Barriers_wall_meets_roof_final.pdf) and 2004’s “Air Barriers, Research Report,” by Joseph Lstiburek (www.buildingscience.com/documents/reports/rr-0403-air-barriers). Additional references can be found at the Air Barrier Association of America (ABAA) web site at www.airbarrier.org. (back to top)
2 The impact of air barriers’ vapor permeance on moisture management has been discussed by co-author Spinu in two other articles that were published in The Construction Specifier: April 2007’s “To Be or Not to Be Vapor-Permeable,” and November 2012’s “Designing without Compromise: Balancing Durability and Energy Efficiency in Buildings.” (back to top)
3 The wind loads and schedule considered in these tests have been developed by the ASTM standard committee. While the authors are not part of this committee, it is possible one of the reasons for developing multiple pressure loads is to extrapolate the data at low pressures through linear regression. At low pressure loads, the errors are larger than at high pressures, so it is important to have multiple data points. (back to top)
4 The standards assume the air barrier plane will take the full wind loads (even though this would only be true for pressure-equalized façades). (back to top)
5 The air barrier structural loading is based on the assumption the air barrier plane: (1) takes the full wind loads (even though this only occurs for pressure-equalized façade systems), (2) experiences thousands of cycles of high positive and negative pressure loads during its service life, and (3) experiences two severe storms in the first 15 years of service. The steel studs shown buckling in the picture are at the very high end of the pressure loads. The point is when proper fasteners and spacing are used, air barriers can perform under wind gust conditions. These tests are quite stringent, but air barriers must perform for the life of the building envelope and such conditions could be occasionally experienced. (back to top)

Maria Spinu, PhD, LEED AP, is a building scientist with DuPont Building Knowledge Center, where she has led global building science and sustainability initiatives for the commercial market for the past decade. She is the author of 16 patents and has been a speaker at many regional, national, and international conferences on building science and sustainability topics. Spinu can be contacted via e-mail at maria.spinu-1@dupont.com.

Benjamin Meyer, RA, LEED AP, is a building science architect with DuPont Building Knowledge Center, where he works with customers and industry associations to answer questions on commercial building envelope design. Meyer is on the board of the Air Barrier Association of America (ABAA), a member of the Materials and Resources Technical Advisory Group of LEED, and also a consultant of the ASHRAE 90.1 Envelope Subcommittee. He can be reached benjamin.meyer@dupont.com.

Andrew Miles is a forensics engineer, providing technical support as part of the DuPont Tyvek Specialist network. His responsibilities include mock wall testing and field investigations related to use, performance, and customer concerns. Miles can be e-mailed at andrew.s.miles@dupont.com.

Success in the Balance: Form and function with balanced doors

Photo © Heather Collins Roe Photography

Photo © Heather Collins Roe Photography

by Mark Graves

Specifying doors is a complex task, given the various choices available to meet aesthetic and functional needs. When choosing a marquee entry, a specifier needs to consider several criteria.

First, the amount of traffic to the door must be anticipated. If the door’s location subjects it to constant use from foot traffic and exposure to the environment, the assembly needs to be a solid product resistant to deterioration and abuse. Second, the building’s wind and stack action pressure must be considered. The door needs to open easily and remain closed in all conditions. Third, the door must be able to be opened easily by all users, despite size and weight. Finally, if applicable, the door’s leaf projection to the exterior should be reviewed to prevent it from protruding onto the sidewalk area and possibly obstructing pedestrian traffic.

Available for more than 80 years, balanced doors can meet these challenges. Their design and solid construction means the fulcrum is inset at one-third the door’s width, which allows for large, heavy, and durable doors to be opened with relative ease. This design facilitates fluid opening and closing, even when strong external wind pressures and internal stack pressures exist, as the door works with—rather than against—these forces. This also ensures doors will remain closed and not flutter when confronted with uneven air pressure, ultimately reducing a facility’s energy costs.

Design options and possibilities
Balanced doors can complement any design, or act as the design centerpiece of the buildings they serve. Commonly offered in bronze, stainless steel, steel, aluminum, and wood, manufacturers can produce doors with virtually infinite combinations of materials, sizes, and designs. Sidelites and transoms can also be incorporated around the doors, but it is recommended architects and designers work with a curtain wall or storefront manufacturer to achieve a unified aesthetic between the door system and surrounding building area.

The main entrance of the Lakewood Cemetery’s Garden Mausoleum in Minneapolis showcases a pair of custom muntz-bronze balanced doors covered in decorative bronze grilles with a wide perimeter accent bronze trim. [CREDIT] Photo © Paul Crosby

The main entrance of the Lakewood Cemetery’s Garden Mausoleum in Minneapolis showcases a pair of custom muntz-bronze balanced doors covered in decorative bronze grilles with a wide perimeter accent bronze trim. Photo © Paul Crosby

A durable and design-flexible balanced door system can be composed of formed-up bronze or stainless steel. Sheet stock is bent and formed to desired specifications, and is flexible enough to accommodate details such as flush-type glazing, wider door stiles and rails, and various finish options.

Balanced doors made from formed stainless steel or bronze are constructed with a minimum stile and top rail of 69.8 mm (2 ¾ in.), and a minimum bottom rail height of 152 mm (6 in.), though 254 mm (10 in.) is recommended to comply with the current 2010 Americans with Disabilities Act (ADA). The formed-up glass stops can accommodate various glass thicknesses from 6.35 to 25-mm (¼ to 1-in.) insulated glass, and have the capacity to accommodate bullet-resistant or blast-mitigation glass by making the door slightly thicker.

The formed-up balanced door features a tie-channel assembly, which extends all the way up and around the vision opening. It is made up of individual channel shapes welded at the corners to form a sub-assembly slid between the door skins. It is then spot-welded (i.e. resistance) into place for superior door rigidity and longevity. The formed-up door also features top and bottom channels, which are placed between the interior and exterior skins. Both the door skin and subframe materials are 2.2-mm (0.09-in.) thick bronze or stainless steel, which is among the heaviest used in door construction.

Extruded aluminum balanced doors are a budget option similar in structural appearance to formed stainless steel or bronze balanced doors. Aluminum extrusions are used in place of the formed metal. Aluminum material is available in an almost limitless number of polyvinylidene fluoride (PVDF) or powder coating paint finishes, as well as traditional anodized finishes.

A balanced door pivots at two-thirds of the door, distributing the weight and creating a balance allowing the door to easily open. The bottom arm (shown above) is one of two connections between the door leaf and frame. One end of the bottom arm is connected to the door by a stainless steel pin which projects out of the door bottom pivot and engages into the arm. The other end of the bottom arm is welded to the full-height steel tube portion of the hinge pivot assembly.  [CREDIT] Photo © Heather Collins Roe Photography

A balanced door pivots at two-thirds of the door, distributing the weight and creating a balance allowing the door to easily open. The bottom arm (shown above) is one of two connections between the door leaf and frame. One end of the bottom arm is connected to the door by a stainless steel pin which projects out of the door bottom pivot and engages into the arm. The other end of the bottom arm is welded to the full-height steel tube portion of the hinge pivot assembly. Photo © Heather Collins Roe Photography

Stiles versus no stiles on a tempered glass door
For many years, architects have been designing entrances with less metal and more glass, which often leads to requests for tempered glass balanced doors. A tempered glass door may offer aesthetic benefits, but there are major issues that need to be considered when using them in a high-traffic exterior environment.

Balanced doors are available with tempered glass where the glass is the structure of the door, either with or without stiles. In either door type, full top and bottom rails are required to accommodate the balanced hardware, so patch block fittings are not an option.

Most balanced door manufacturers strongly recommend using stiles for added strength, door integrity, and energy efficiency. A narrow stile is in some cases unnoticeable, especially after the addition of push/pull or panic hardware.

Stiles provide edge protection and structural strength for a tempered glass door. When stiles are added, there is no exposed edge to the glass. This protects the vulnerable edge of the glass from possible damage and breakage, which could lead to personal injury and litigation. Glass deflection occurs as the glass gets taller. Glass is a flexible material; one way to mitigate this problem is to use vertical stiles on the glass edges.

On an aluminum tempered glass door, the narrow stiles are solid aluminum bar. On a stainless steel or bronze door, the stiles also use the solid aluminum bar and then are cladded to match the rest of the door using 2.2-mm (0.09-in.) cladding.

When architects specify tall doors over 2.7 m (9 ft), and are not using vertical stiles, 19-mm (¾-in.) glass is required. Adding narrow stiles, such as 25-mm (1-in.) aluminum stiles or 28.5-mm (1 1/8-in.) stainless steel or bronze stiles, allows the balanced door manufacturer to use 12.7-mm (½-in.) thick glass, in lieu of the 19-mm glass. This cuts down on the overall weight and cost of the door, as 19-mm glass is significantly more costly and heavier than 12.7-mm glass.

Stainless steel stile and rail-type balanced doors were used on New York by Gehry in New York City to provide a transparent aesthetic for the glass-enclosed lobby. [CREDIT] Photo © Barry Schwartz Photography

Stainless steel stile and rail-type balanced doors were used on New York by Gehry in New York City to provide a transparent aesthetic for the glass-enclosed lobby. Photo © Barry Schwartz Photography

There is no effective way to place weatherstripping on a door that does not have vertical stiles. Stiles allow the door to be properly weatherstripped, which is necessary due to more stringent energy codes including American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) 90.1, Energy Standard for Buildings Except Low-rise Residential Buildings and the International Energy Conservation Code (IECC).

A 25-mm vertical stile allows polypropylene pile weatherstripping to be incorporated into the door. Without weatherstripping, there is poor energy efficiency. There are clear acrylic weatherstripping solutions that are taped on, but they tend to be ineffective and prone to discoloration and cracking. They also easily lose their adhesion and are often knocked off the door. With a stile, a tighter seal and a more energy-efficient solution can be created, in addition to eliminating wind noise that can occur when there are gaps around the door.

Frame options
A balanced door can be designed with a concealed hinge pivot shaft (within the vertical framing), making a full three-sided frame around the door, or more minimal framing can be used by having a header only with an exposed clad hinge pivot shaft. By exposing the hinge pivot shaft, it balances the metal used for the stile on the pull side as the eye is drawn to the vertical usage of metal.

The minimal frame approach is typically used in curtain wall applications and the shaft is often covered in the corresponding door material. The look is less bulky, but the balanced door still needs a header to contain the check and guide channel portion of the balanced hardware. Since there is no vertical framing and the shaft/cladding rotate, the header needs to be properly supported by the curtain wall material from above.

The custom balanced doors at the museum entrance of the Exploratorium in San Francisco feature stile and rail-type construction of painted extruded aluminum material. Photos © Heather Collins Roe Photography

The custom balanced doors at the museum entrance of the Exploratorium in San Francisco feature stile and rail-type construction of painted extruded aluminum material. Photos © Heather Collins Roe Photography

Engineering considerations
Engineering considerations to keep in mind to accommodate balanced doors include:

  • top and bottom arm swing interference;
  • hardware projection;
  • finish hardware; and
  • access to balanced door hardware.

A clear space needs to be provided for top and bottom arm swings and door travel to the interior. A balanced door projects to the interior—as the door opens, the heel edge swings inward and the arms rotate inward as well. This means there cannot be any interference with the ceiling for the balanced door to operate properly. For example, a soffit ceiling cannot be placed too close to the interior door opening adjacent to the doorframe’s back side. There needs to be enough room to allow the door to fully open.

The floor also needs to be kept free of interference for the balanced door path to the full open position. The floor cannot slope and, just as the ceiling above, the door needs room to allow the heel edge to swing in and the arms to rotate.

It is also important to ensure there are no columns or permanent obstruction blocking the heel edge. If the balanced doorframe is going to be partially recessed into an interior wall, it can be recessed about 38 mm (1 1/2 in.) and still provide enough space for the arms to rotate inward. A pocket in the surrounding wall material will be required if the frame is recessed more than 38 mm to allow the arms to fully rotate. If the frame is to be recessed into the exterior wall, the pull handle needs adequate clearance so it will not crash into the wall when the door is in the full open position.

Gotham West, a luxury rental apartment building in New York City, facilitates access with two single narrow stile bronze balanced door units with a satin finish. The narrow stile design features tempered glass construction, containing a top and bottom rail that secures the glass to the hinging mechanism. [CREDIT] Photo © Barry Schwartz Photography

Gotham West, a luxury rental apartment building in New York City, facilitates access with two single narrow stile bronze balanced door units with a satin finish. The narrow stile design features tempered glass construction, containing a top and bottom rail that secures the glass to the hinging mechanism. Photo © Barry Schwartz Photography

The hardware and grillwork projection off the door’s exterior face must also be considered. Most balanced door manufacturers advise against using a horizontal pull handle because it cannot go all the way across the door’s face without interfering with the door jamb, preventing the door from fully opening. The door handles provide visual cues, with a vertical pull indicating pull action and horizontal pull indicating a push action. Users with physical limitations, such as crutches, find it difficult to open a door with horizontal pulls. The maximum projection of hardware and grillwork off the exterior face of the door at hinge side is 12.7 mm (½ in.).

The same finish hardware items used on a conventional swing door can be used on a balanced door. This can provide design and usage continuity throughout a space. Balanced doors can accommodate:

  • push/pulls (except horizontal pulls);
  • deadlocks;
  • flushbolts; and
  • manual panic exit devices and electronic locking hardware (i.e. surface maglocks, concealed shearlocks, electronic latch retraction panic exit devices, and electric release strikes).

It should be noted there are specific guidelines addressing the use of panic devices on a balanced door set by the International Building Code (IBC) and the National Fire Protection Association (NFPA).1

IBC, Section 1008.1.10.2, “Balanced doors,” states:

If balanced doors are used and panic hardware is required, the panic hardware shall be the push-pad type and the pad shall not extend more than one-half the width of the door measured from the latch side.

NFPA 101 Life Safety Code, Section 7.2.1.13, “Balanced door assemblies,” states:

A pair of balanced doors offers a pleasing aesthetic to match the exterior of the decades-old Blessed Sacrament Cathedral in Greensburg, Pennsylvania. Both doors contain a total of six bronze panels—three on the front and three on the back—and weigh 317.5 kg (700 lbs), making the balanced design necessary to facilitate easy opening and closing. [CREDIT] Photo courtesy Ellison Bronze

A pair of balanced doors offers a pleasing aesthetic to match the exterior of the decades-old Blessed Sacrament Cathedral in Greensburg, Pennsylvania. Both doors contain a total of six bronze panels—three on the front and three on the back—and weigh 317.5 kg (700 lbs), making the balanced design necessary to facilitate easy opening and closing.
Photo courtesy Ellison Bronze

If panic hardware is installed on balanced door leaves, the panic hardware shall be of the push-pad type, and the pad shall not extend more than approximately one-half the width of the door leaf, measured from the latch stile.

This requirement helps reduce the force needed to open the door leaf. The panic hardware actuating bar should be close to the latch side of the door and away from the roller and hinge side. This arrangement is more effective when using push-pad panic hardware that readily instructs the user where to push instead of a crossbar-style panic device.

If using stiles, a design that can accommodate the hardware requirements should be specified. For example, a concealed vertical rod-type panic device can only be used on a stile and rail type door with a wider stile, not on a narrow stile tempered glass door.

Finally, it is important to keep the balanced door hardware accessible. If the balanced door hardware needs to undergo maintenance or repair, the guide channels and doorjambs cannot be concealed.

Conclusion
The long-term functional and aesthetic benefits a balanced door system provides make it a suitable choice for commercial, institutional, and monumental facilities. When making the decision to incorporate a balanced door into the building design, it is important to choose an experienced manufacturer skilled in the design and maintenance of balanced door systems. The manufacturer should have a strong reputation for lasting doors and serviceability.

All balanced door systems should be periodically maintained to ensure a long service life, and an annual inspection is recommended. It is important to select a manufacturer that offers a comprehensive warranty for the entire door system, including the door, frame, and balanced hardware.

Notes
1 For more information, visit www.iccsafe.org and www.nfpa.org. (back to top)

Mark Graves is the president of Ellison Bronze Inc. He has more than 30 years of experience in the general construction, architecture, and manufacturing industries. Graves has spent 25 years of his career manufacturing custom balanced doors with Ellison. He can be reached via e-mail at mgraves@ellisonbronze.com.

Understanding New Accessibility Requirements for Doors

All images courtesy Allegion

All images courtesy Allegion

by Lori Greene, AHC/CDC, CCPR, FDAI

The 2010 Americans with Disabilities Act (ADA) Standards for Accessible Design went into effect in March 2012, but there are several requirements that continue to surprise architects and specifiers.

This article examines four particular changes related to doors on an accessible route:

  • door hardware must now operate with 22.2 N (5 lb) of force—a limit most panic hardware does not meet;
  • any low-energy automatic operators actuated by a motion sensor must meet the safety requirements for a full-powered automatic operator—possibly including safety mats and guide rails;
  • bottom rails of manual swinging doors must be at least 254 mm (10 in.) high, and no hardware may protrude from the push side within the bottom 254 mm (10 in.); and
  • automatic operators on doors that do not provide proper egress-side maneuvering clearance for a manual door must have standby power.
A change submitted for the next edition of International Code Council (ICC) A117.1, Accessible and Usable Buildings and Facilities, would limit rotational force to 3 N-m (28 inch-pounds), and operation by a pushing/pulling motion to 66 N (15 lb).

A change submitted for the next edition of International Code Council (ICC) A117.1, Accessible and Usable Buildings and Facilities, would limit rotational force to 3 N-m (28 inch-pounds), and operation by a pushing/pulling motion to 66 N (15 lb).

Some of these issues are specific to the 2010 ADA, while others are also addressed by International Code Council (ICC) A117.1, Accessible and Usable Buildings and Facilities. This standard is referenced by the International Building Code (IBC), International Fire Code (IFC), and National Fire Protection Association (NFPA) 101, Life Safety Code, for doors on an accessible route.

Operable force for door hardware
An editorial change was made to the 2010 ADA to limit the operable force for door hardware to 22.2 N (5 lb). Editorial changes are normally used to address errors or make clarifications that do not affect the scope or application of the code requirements. These changes do not go through the normal code development process (i.e. committee hearings and opportunities for public comment). In other words, this change was unexpected.

In the 1991 edition of ADA, door hardware was required to have:

a shape that is easy to grasp, and does not require tight grasping, tight pinching, or twisting of the wrist to operate.

This is the same language currently included in A117.1. No force limitation was mentioned with regard to the operation of hardware.

The 2010 edition of ADA changed the section that applies to door hardware, by referring to Paragraph 309.4–Operation:

Operable parts shall be operable with one hand and shall not require tight grasping, pinching, or twisting of the wrist. The force required to activate operable parts shall be 5 pounds (22.2 N) maximum.

A low-energy automatic operator must be actuated by a knowing act (e.g. this wall-mounted push button), or must comply with the requirements of a Builders Hardware Manufacturers Association (BHMA) standard.

A low-energy automatic operator must be actuated by a knowing act (e.g. this wall-mounted push button), or must comply with the requirements of a Builders Hardware Manufacturers Association (BHMA) standard.

By referencing Paragraph 309.4, a limit for the operable force of hardware was established.

Conflicts and clashes
This change created conflicts with other codes and standards, and even within the 2010 ADA standards. For example, in ADA, Section 404.2.9 addresses door and gate opening force—the force required to physically open the door. This section states the 22.2-N (5-lb) limit on opening force does not apply to the force required to release the latchbolts. This implies the allowable force required to release latchbolts could be greater than the 22.2-N (5-lb) opening force. The U.S. Access Board unofficially acknowledged there was a conflict between the opening force section and the operable force required by reference, but to date the standards have not been modified.

Another conflict lies with IBC, IFC, and NFPA 101, for which panic hardware is required to operate with a maximum of 66 N (15 lb) of force to release the latch. In an attempt to establish a level of operable force aligned with other codes and standards, a change proposal was submitted for the 2015 edition of ICC A117.1. If approved, the proposal would establish a limit of 66 N (15 lb) maximum for hardware operated by a forward, pushing, or pulling motion, and 3 N-m (28 inch-pounds) maximum for hardware operated by a rotational motion.

Additionally, the 2013 California Building Code (CBC) includes language virtually identical to the 2010 ADA operable force requirements, and requires hardware to operate with 22.2 N (5 lb) of force, maximum. However, the code contains conflicting language in Section 1008.1.10–Panic and Fire Exit Hardware, which requires panic hardware to operate with a maximum of 66 N (15 lb) of force.

Given the change to CBC and the delay in addressing the conflict within the 2010 ADA standards, there are projects where the 22.2-N (5-lb) limit is being enforced for both lever-operated and panic hardware. For each project, a decision must be made regarding whether to use hardware meeting the requirements of IBC (and its referenced standard, ICC A117.1), or whether to specify hardware that meets the 22.2-N limit to avoid a conflict with ADA standards.

If a motion sensor is used to actuate a door with an automatic operator, then guide rails and safety sensors are typically required.

If a motion sensor is used to actuate a door with an automatic operator, then guide rails and safety sensors are typically required.

Actuators for automatic operators
From a codes and standards perspective, there are three basic types of automatic operators for swinging doors:

  • power-assist;
  • low-energy; and
  • full-power.

Power-assist operators reduce the opening force so the door can be manually opened more easily, but some manually applied force is still necessary. These operators are usually activated by pushing or pulling the door, although occasionally a wall-mounted actuator is employed to reduce the force only for users who need that feature.

Low-energy operators are often used when the door will be opened manually by some users and automatically by others. The doors are subject to limitations on opening speed and force to curtail the generation of kinetic energy and the potential for injury. Further, they must be operated by a ‘knowing act,’ as described later in this article.

Due to these limits, most doors with low-energy operators are not required to have safety sensors, control mats, or guide rails. Both power-assist and low-energy operators must comply with American National Standards Institute/Builders Hardware Manufacturers Association (ANSI/BHMA) A156.19, Power-assist and Low-energy-operated Doors.

Full-power operators are typically found on high-use openings like the entrance to a grocery store or department store. These operators are not subject to the same restrictions on speed and force, and safety sensors or control mats and guide rails are required to prevent the doors from opening if someone is in the path of the door swing. Full-power operators must comply with ANSI/BHMA A156.10, Standard for Power-operated Pedestrian Doors.

The 2007 edition of ANSI/BHMA A156.19 introduced a requirement for power-assist and low-energy-power-operated doors to be activated by a ‘knowing act,’ and this requirement carries forward to the 2013 standard. The ‘knowing act’ method may be:

  • a push-plate actuator or non-contact switch mounted on the wall or jamb;
  • the act of manually pushing or pulling a door; or
  • an access control device like a card reader, keypad, or keyswitch.

The A156.19 standard also makes recommendations regarding the mounting location of a knowing act switch. Actuator switches should be located:

  • a maximum of 3.7 m (12 ft) from the center of the door (0.3 to 1.5 m [1 to 5 ft] is preferred)—when further, the recommended increased hold-open time is one additional second per 0.3 m (1 ft) of distance;
  • where the switch remains accessible when the door is opened, and the user can see the door when activating the switch;
  • in a location where the user would not be in the path of the moving door; and
  • at an installation height of 864 mm (34 in.) minimum and 1219 mm (48 in.) maximum above the floor.

The 2010 ADA and ICC A117.1 contain requirements pertaining to the actuators for automatic doors in addition to what is included in the referenced standard. Clear floor space for a wheelchair must be provided adjacent to the actuator, and beyond the arc of the door swing. The mounting height is variable, depending on the reach range associated with the switch location. However, the range recommended by ANSI/BHMA standards is acceptable for most applications. Actuators must not require tight grasping, pinching, or twisting of the wrist to operate, and the operating force is limited to 22.2 N (5 lb) maximum.

This door lacks proper maneuvering clearance on the egress side. If an automatic operator were to be installed to overcome this issue, the 2010 ADA requires standby power for the operator.

This door lacks proper maneuvering clearance on the egress side. If an automatic operator were to be installed to overcome this issue, the 2010 ADA requires standby power for the operator.

Stepping into the field of a motion sensor is not considered a knowing act. If automatic operation via a motion sensor is desired, automatic doors must comply with the standard for full power operators—ANSI/BHMA A156.10, instead of A156.19. This means even though the door may have a low-energy operator, it has to meet the same requirements as a full-power operator, including the safety sensors or control mats and guide rails.

Typically 762 mm (30 in.) high, guide rails are required on the swing side of each door. For some locations, the need for guide rails may mean motion sensor operation is not feasible. When certain criteria are met, walls may be used in place of guide rails. When doors are installed across a corridor, guide rails are not required if the distance between the wall and the door in the 90-degree open position does not exceed 254 mm (10 in.).

The 2013 California Building Code requires two push-plate actuators at each actuator location—one mounted between 178 and 203 mm (7 and 8 in.) from the floor to the centerline, and the other mounted between 762 and 1118 mm (44 in.) above the floor. Vertical actuation bars may be used in lieu of two separate actuators, with the bottom of the bar at 127 mm (5 in.) maximum above the floor and the top at 889 mm (35 in.) minimum above the floor.

Actuators must be in a conspicuous location, with a level and clear ground space outside of the door swing. The minimum size for push plates is 102 mm (4 in.) in diameter or 102 mm square, and the minimum operable portion for vertical actuation bars is 51 mm (2 in.) wide. Both types of actuators must display the International Symbol of Accessibility.

While all these requirements have the same basic intent, it is best to check state and local codes to see which standard has been adopted, and what the specifics are in reference to actuators for automatic operators. It is important to verify the actuator type/quantity, location, and any additional requirements. Further, one must keep in mind additional safety features—including sensors and guide rails—may be required for low-energy operators actuated by a motion sensor.

Some jurisdictions require actuators mounted in two positions, or a vertical bar actuator that will allow the door to be operated by a hand/arm or a crutch, cane, or wheelchair footrest.

Some jurisdictions require actuators mounted in two positions, or a vertical bar actuator that will allow the door to be operated by a hand/arm or a crutch, cane, or wheelchair footrest.

Standby power for automatic operators
The 2010 Americans with Disabilities Act includes revisions to the section on automatic doors with regard to clear width and maneuvering clearance. (These have not been included in A117.1 to date.) The ADA standards read:

404.3.1 Clear Width. Doorways shall provide a clear opening of 32 inches (815 mm) minimum in power-on and power-off mode. The minimum clear width for automatic door systems in a doorway shall be based on the clear opening provided by all leaves in the open position.

404.3.2 Maneuvering Clearance. Clearances at power-assisted doors and gates shall comply with 404.2.4. Clearances at automatic doors and gates without standby power and serving an accessible means of egress shall comply with 404.2.4.
EXCEPTION: Where automatic doors and gates remain open in the power-off condition, compliance with 404.2.4 shall not be required.

According to both accessibility standards and egress requirements, most doors have to provide at least 815 mm (32 in.) of clear opening width. (For pairs of doors, at least one leaf has to provide this.) The aforementioned Paragraph 404.3.1 states the required clear opening width must be provided “in power-on and power-off mode.” The clear opening’s full width is considered—for example, a 1.5-m (5-ft) pair of automatic doors would provide sufficient clear width even though neither leaf meets the minimum clear width for a manual door.

Maneuvering clearance for manual doors is addressed in Section 404.2.4 of the 2010 ADA. This section establishes the minimum space around the door needed by a wheelchair user to manually operate the door. The previously cited Paragraph 404.3.2 requires power-assisted doors and gates (manually operated but with reduced opening force) to have the same maneuvering clearance as manual doors. Automatic doors and gates serving an accessible means of egress without standby power would also need the required maneuvering clearance. Therefore, automatic doors and gates with standby power do not need the maneuvering clearance that would be required for a manual door.

Manual doors on an accessible route must have a smooth surface on the push side with no protruding hardware within 254 mm (10 in.) of the floor or ground. In the photo at left, these components could inhibit passage through a door opening by catching a crutch, cane, walker, or wheelchair.

Manual doors on an accessible route must have a smooth surface on the push side with no protruding hardware within 254 mm (10 in.) of the floor or ground. In the photo at left, these components could inhibit passage through a door opening by catching a crutch, cane, walker, or wheelchair.

If an existing door serving an accessible means of egress does not have the required maneuvering clearance and an auto operator is added to overcome that problem, the operator needs to have standby power (unless the door stands open on power failure per the exception). This applies to doors part of a means of egress that must be accessible in an emergency, and is intended to avoid entrapment of a person with a disability if there is a power failure. The standard does not include a requirement for how much standby power must be provided.

It is important to keep in mind automatic operators on fire-rated doors are required to be deactivated upon fire alarm. Therefore, an automatic operator with standby power should not be used on a fire-rated door to overcome maneuvering clearance problems because it will not be functional when the fire alarm is sounding.

Flush bottom rails
For many years, ICC A117.1 has included a requirement for a 254-mm (10-in.) high flush bottom rail on manual doors, and this requirement is now included in the ADA standards. The text of both standards is similar, except ADA also addresses existing doors. (This requirement appears in the “Manual Doors” section of both publications, so it does not apply to automatic doors.)

The purpose is to avoid projections that could catch a cane, crutch, walker, or wheelchair and inhibit passage through the door opening, so the requirement applies to the push side of the door only. The 254-mm (10-in.) measurement is taken from the floor or ground to the top of the horizontal bottom rail, extending the full width of the door. Prior to the 2003 edition of A117.1, the required dimension was 305 mm (12 in.).

Manual doors on an accessible route must have a smooth surface on the push side with no protruding hardware within 254 mm (10 in.) of the fl oor or ground. In the photo at left, these components could inhibit passage through a door opening by catching a crutch, cane, walker, or wheelchair.

Manual doors on an accessible route must have a smooth surface on the push side with no protruding hardware within 254 mm (10 in.) of the floor or ground. In the photo at left, these components could inhibit passage through a door opening by catching a crutch, cane, walker, or wheelchair.

The standards require the surface of swinging doors and gates within 254 mm (10 in.) of the finish floor or ground to have a smooth surface on the push side that extends the full width of the door or gate. Narrow bottom rails and protruding surface bolts, surface vertical rods, kick-down stops, and full-height door pulls installed on the push side of the door would not comply with this requirement for a 254-mm (10-in.) high smooth surface. Horizontal or vertical joints in this surface must be within 1.6 mm (1/16 in.) of the same plane. If a kick plate is added to a door with a narrow bottom rail to resolve this problem, the cavity between the kickplate and the glass or recessed panel must be capped.

There are several exceptions to this requirement. Sliding doors are not required to comply. Tempered glass doors without stiles are not required to have a 254-mm (10-in.) bottom rail (if the top of the bottom rail tapers at 60 degrees minimum from the horizontal), but protruding hardware is not allowed in the 254-mm (10-in.) high area. Doors that do not extend to within 254 mm (10 in.) of the finish floor or ground are also exempt.

As outlined in ADA, existing doors are not required to provide the 254-mm smooth surface, but if kick plates are added to widen the bottom rail, the gap between the top of the plate and the glass must be capped. Existing doors are not addressed by A117.1, which is typically used for new applications as referenced by IBC. Now the standards are consistent, and increased awareness and enforcement of this requirement seem likely.

Conclusion
With regard to these changes in the Americans with Disabilities Act standards, some accessibility requirements are not prescriptive and enforcement varies by jurisdiction. Therefore, it can be difficult to apply the standards, especially when conflicts exist. Additionally, some states have established their own accessibility standards. Following the most stringent requirements can help to avoid problems, and the local authority having jurisdiction (AHJ) can also provide assistance to determine what is required.

Lori Greene, AHC/CDC, CCPR, FDAI, is the codes and resources manager for Allegion. She has been in the industry for more than 25 years, and used to be a hardware consultant writing specifications. Greene is a member of CSI, the Door and Hardware Institute (DHI), the International Code Council (ICC), the National Fire Protection Association (NFPA), and the Builders Hardware Manufacturers Association (BHMA) Codes and Government Affairs Committee. She has a monthly column on code issues in Doors & Hardware, and blogs at www.iDigHardware.com (or www.iHateHardware.com). Greene can be contacted via e-mail at lori.greene@allegion.com.