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74 All airport SIPs share a common goal of providing homeowners, students, and worshippers quiet environments in which to carry out activities without disruption from aircraft noise. Geo- graphic diversity, wide-ranging climatic conditions, local construction practices, and building codes dictate acoustical and architectural applications that are appropriate to particular com- munities. Programs across the country tailor their sound insulation treatments to meet unique local conditions as well as the end userâs needs for user-friendly, architecturally appropriate, historically correct, and acoustically effective products. Finding the right combination of appropriate treatments that provide acoustical performance, building owner satisfaction, operational ease, reasonable cost, appropriate lead times for fabrica- tion and delivery, extended warranty, and customer service is critical in delivering a successful sound insulation program. Sound insulation treatments are designed to reduce noise entering into interior space through the exterior building envelope. Since windows and doors can account for the majority of unwanted noise entering a standard structure, SIPs have focused their efforts on creating better barriers for these major noise paths while being mindful of ancillary noise paths. Effective collaboration between program managers, designers, and manufacturers of acoustical products has resulted in a variety of architectural solutions. 5.1 Treatment Goals As explained in Chapter 4, the FAA has set two measureable goals to prove the efficacy of sound insulation. They are that the post-treatment interior noise level is equal to or less than 45-dB DNL and that the treatments have achieved at least 5 dB of NLR. To meet these goals, the design effort needs to establish what the existing noise-reducing performance is of the build- ing being treated and to what noise level it is exposed. This information can be obtained either through testing every building to be treated or undertaking an effort to establish statistical per- formance based on construction typologies. Residential neighborhoods with standard construc- tion typologies are suited to a statistical understanding of performance. Public institutional buildings tend to be unique and require individualized testing and design. Once a performance objective is established, the design effort can begin. This chapter presumes that a building has met qualifying thresholds of noise exposure discussed in Chapters 2 and 4 and is eligible for treatment. In addition to measurable acoustic goals, successful programs set a goal to establish good rela- tionships with the community served by the program. Many aspects of community outreach are discussed in Chapter 3. However, there are aspects of treatment design that contribute to meeting the goal of community satisfaction. These include choosing products that are of good quality, C H A P T E R 5 Design of Architectural Treatment Strategies
Design of Architectural Treatment Strategies 75 that are long lasting, and that perform well; designing treatments that maintain the aesthetic characteristics of the neighborhood as much as possible; and detailing treatment installations to reduce disruption to occupants during construction. Defining these aspects for each program can be informed by programs and practices at airports across the country, but the final determi- nation of what is appropriate is a local decision. 5.1.1 Determining Treatment Needs Exterior noise levels ranging from 65-dB DNL to upwards of 75-dB DNL affect buildings treated for sound insulation. The majority of airports have reduced their highest noise contours to the extent that most residences are not exposed to noise above 70-dB DNL; however, some larger airports still have noncompatible structures in high noise contours. It is important in determining treatment requirements to know the NLR of an existing building and the exterior noise exposure level in which it is located. The mathematical difference between the two deter- mines the noise level reduction needed to bring the building into compliance with the goal of having interior exposure at or below 45-dB DNL. While 5-dB NLR is the minimum reduction to achieve, some buildings will require more due to their exterior exposure level or deficient pre- existing construction. Coordinate this with the acoustical consultant as part of the early design process. Noise contours are determined in 5-dB increments (e.g., 65 dB to 70 dB and 70 dB to 75 dB). The 2005 guidelines state, âIn determining the required noise reduction, the higher end of the noise zone range is always used.â1 So exposure within the 65-dB to 70-dB DNL is regarded as exposure to 70-dB DNL. This accommodates rounding and statistical margins of error in mea- surements. Noise contour 70 dB DNL 70 dB NLR required to reach â¤45 dB 25 dB 25 dB Pre-existing NLR 19 dB 21 dB Treatment goal 6 dB 5 dB (program minimum) Table 5.1 shows the successful average NLR achieved by sound insulating programs as verified in post-construction testing of approximately 4,000 homes. These data span many programs and years. 5.1.2 Understanding Building Code Regulations Program treatments must be designed and constructed in accordance with prevailing building codes. While a single national building code based on the IBC is slowly emerging, each state, and 1 Department of the Navy, Naval Facilities Engineering Command, Guidelines for the Sound Insulation of Residences Exposed to Aircraft Operations, as referenced in FAA AC 150/5000-9A, April 2005. pp. 3â18. NLR Region Pre- Test Post- Test Increase Northern 27.2 34.1 6.9 Western 25.2 32.2 7.0 Southern 23.9 32.8 8.9 Table 5.1. Average NLR increase across many programs.
76 Guidelines for Airport Sound Insulation Programs sometimes municipality, may adopt variations in its requirements for construction. Additionally, each jurisdiction may have adopted different editions or appendices of the IBC, which is updated every 3 years. In code parlance, the work of sound insulation programs is âalterationâ rather than ânew construction.â There are three levels of alteration, each with increasing requirements based on the extent and value of work. Questions may arise as to whether a building permit is even needed. That determination is strictly a local issue, and a ruling will be required from each jurisdiction affected by the SIP. In some jurisdictions, homeowners may be able to self-perform alterations to their homes without a building permit; however, in most jurisdictions the replacement of HVAC systems and the use of licensed contractors, design professionals, and federal funds necessitates the issuance of building permits. The codes for residential and institutional buildings differ greatly, and programs will need to understand these differences if working on both types of properties. An important program start-up activity is to meet with the local building official(s) and pre- sent the program protocols. It is a best practice recommendation to go to that meeting with a code, zoning, and permitting review already completed, accompanied by a prepared interpreta- tion of the requirements that will affect the SIP. If the program spans multiple jurisdictions, the building officials from each jurisdiction will need to be consulted. If there is a difference in code interpretation between jurisdictions, a program may want to adopt the strictest interpretation for all of their treatments to avoid confusion among homeowners, designers, and contractors. Building codes are revised regularly and often in response to situations that have become apparent through experience. Most of the buildings treated by sound insulation programs are older and built under codes that have since been superseded. Safety is the first consideration of building officials, so while a structure may be able to persist in its present or grandfathered con- dition, the action of pulling a construction permit may present an opportunity for officials to correct issues they deem to be of importance for life safety. This can lead to resizing of windows, doors, or mechanical systems, or prevent ceiling treatments that would lower an already non- conforming ceiling height. Programs use the phrase âlike for likeâ to indicate that treatments replace existing conditions and do not constitute a renovation project. Where necessary, pro- grams may need to enlarge windows or doors for emergency egress, build safer landings at entrances, or increase electrical services and air ducts for ventilation systems in order to offer the treatments while meeting the requirements of the authority having jurisdiction. The U.S. Department of Energy (U.S. DOE) requires buildings to be energy efficient, and many state and local jurisdictions have adopted energy conservation codes. These could include thermal performance, like U-value or solar heat gain, that restricts the use of some types of win- dows or glass. Further discussion of energy issues is contained in Chapters 7 and 8. 5.1.3 Best Practice Recommendations: Treatment Goals 1. Meet with the local building official(s) and present the program protocols; go to that meeting with a code, zoning, and permitting review already completed, accompanied by a prepared interpretation of the requirements that will affect the SIP. 2. If the SIP spans multiple municipalities and there is a difference in code interpreta- tion between jurisdictions, a program may want to adopt the strictest interpreta- tion for all of its treatments to avoid confusion among homeowners, designers, and contractors. 3. Determine a method for identifying noise exposure and pre-existing NLR to calcu- late treatment goals.
Design of Architectural Treatment Strategies 77 5.2 Residential Sound Insulation Treatments The majority of houses in the United States are built using defined standards and materials. Standard residential construction is made up of dimensional wood lumber or masonry units. There are always exceptions, but most programs do not encounter log homes, geodesic domes, traditional adobe, tensile fabric structures, and so forth. When exceptions occur, specialized attention to treatability and eligibility will require professional evaluation, which is outside the realm of these guidelines. Mobile (manufactured)2 homes are not considered standard residen- tial construction and are not eligible for sound insulation. Modular construction required to meet the standards for the IBC is considered standard construction and is eligible for sound insulation. Details for installing the acoustical treatments may need modification to account for differences in the modular construction. PGL 12-09 states, âSome permanent modular structures may be classified as permanent if they meet construction guidelines applied to permanent structures.â3 Building codes have specific regulations governing the construction of modular structures. As such, permanent modular structures may be treatable if they conform to the applicable building codes governing their construction. 5.2.1 Windshield Surveys If a thorough inventory of the housing stock is not part of the Part 150 noise compatibility study, one should be undertaken to catalog the eligible buildings in the contour. Using avail- able municipal GIS data as a base, drive past every property (thus the title âwindshield surveyâ) with the goal of gathering preliminary information on the housing stock and its condition. It is not uncommon to discover discrepancies between public records data and actual conditions at the sites. The data gathered will help identify the housing typologies that inform initial treatment pro- tocols and concepts of neighborhood treatment standards. Establishing typologies also helps generate program policies that can be applied across multiple residences and allows for the for- mation of an approach for choosing homes in pilot studies. Testing each typology provides data that validate and calibrate acoustical modeling for individual homes. These data will direct the design team toward creation of acoustical treatments and selection of appropriate products for the types of houses to be treated. The goals of the windshield survey are to: â¢ Verify the number of residential units within the noise impact area. â¢ Catalog residential housing types in addition to vacant lots, apartments with multiple units, mixed-use commercial, and residential properties found throughout the neighborhoods. â¢ Photograph all housing to correlate with county property records. â¢ Collect data for categorizing all of the properties by type, style, construction, and construc- tion date. â¢ Determine, based on view from the street, if the structure is in good, fair, or poor condition. Condition of the residences generally correlates to ease of construction and potential for issues that can delay participation in the program. â¢ Inform the development of policies and procedures and treatment recommendations to meet neighborhood standards. 2 See Section 2.1.4, Items to Consider Prior to Program Start-Up, Subsection A, Types and Number of Structures, for defini- tions of modular and manufactured homes. 3 U.S. DOT, FAA, PGL 12-09, August 17, 2012, Attachment 1, Â§812 (c)(3),Table 3, p. 1-10.
78 Guidelines for Airport Sound Insulation Programs â¢ Establish if any houses might need a review for historic significance. â¢ Document visible code or safety concerns, such as bedroom windows that are too small or high off the ground to meet current building code standards for emergency egress and fire access. â¢ Identify unique conditions that may be visible to establish potential custom treatments that may affect program policies. â¢ Establish style typology. Since the style of the house can indicate acoustical treatment response, the windshield survey records information about the various styles in treatment- eligible areas. 5.2.2 Housing Typologies The form, materials, and construction of a buildingâs exterior envelope can have an impact on acoustical treatment strategies. In addition to material and construction, the styles of houses can result in noise paths that program consultants need to be aware of. All of the following styles and houses have participated in SIPs. A. Cape Cape-style houses (see Figure 5.1) are prevalent in the eastern and middle United States and were a popular housing type in the post-WWII suburban expansion. The impact to acoustical treatment for this style is the presence of living space directly under the roof without the ben- efit of buffering from attic space. The roof is also low and proximate to head height in upper floor rooms. Due to the location of these rooms directly below the roof structure, additional mass or insulation may need to be added to mitigate noise paths through walls or ceilings if no barrier materials currently exist. The existing knee walls should have a continuous, minimum Â½-in. gypsum wall board (GWB) or equivalent interior finish. The existing inclined and hori- zontal ceilings should have a continuous, minimum Â½-in. GWB or equivalent interior finish. For upper-level living spaces where barrier materials exist at knee walls and ceilings and where there is access to spaces behind knee walls and above ceilings, insulation should be installed at the back side of the wall and/or above ceilings. Doors or access panels to an attic space need to be replaced with a fully weather-stripped interior solid core door if the existing door does not meet acoustical guidelines. Undersized bedroom windows may need to be enlarged for emergency egress. Figure 5.1. Cape-style houses.
Design of Architectural Treatment Strategies 79 B. Ranch The ranch (see Figure 5.2) is a common style that uses siding, stucco, or brick. Many contem- porary ranch houses are on slab foundations, thereby eliminating any acoustic exposure through crawl spaces located under floors. The majority have shallow-pitched gable or hip roofs with small attics beneath. Small attics can create design challenges for locations of air conditioning or ventilation systems. Openings into the attics from the interior will require treatment for reduc- tion of noise though pull-down stairs or attic hatches. There is some possibility for cathedral ceilings. Acoustic exposure will need to be evaluated by testing to determine if treatment to any ceilings will be needed. Many ranch houses have picture windows in the front, and some may be configured with bay/bow windows. Replacement of bay/bow windows with a similar acoustic style is generally not possible. Alternately, an interior storm window mounted flush with the interior wall surface can be installed on the existing bay/bow window unit. Window configura- tions will be dependent on sizes available from manufacturers. C. Raised or Split Ranch The raised or split ranch style includes two-story single-family homes where it is possible that framing will differ between floors. The photos in Figure 5.3 show raised ranch style houses with a hip roof. These houses appear to be frame construction on the second floor and block construc- tion on the first floor. One of the design considerations in mixed framing is that the installation details in the house will vary depending on the wall thicknesses and exterior siding. Split-level ranches involve level changes in the house and often have multiple levels of roof. Exposure to noise may be through walls that are exposed to roof noise. D. A-Frame Contemporary The A-frame contemporary style (see Figure 5.4) is dominated by the roof and has large sec- tions of custom glazing. Shown on the right is a coastal A-frame with hurricane protection panels over trapezoidal glass sections. The roof, the glass, and the volume of space to be treated require thoughtful acoustical, HVAC, and architectural design. E. The Row House and Triple-Decker The row house and triple-decker (see Figure 5.5) styles have in common that they are single- family dwellings in a multifamily setting. A triple-decker is three units stacked vertically. The Figure 5.2. Ranch houses.
80 Guidelines for Airport Sound Insulation Programs Figure 5.3. Raised or split ranch houses. Figure 5.4. A-frame contemporary style houses. Figure 5.5. The row house and triple-decker.
Design of Architectural Treatment Strategies 81 uppermost unit is often under a flat roof with exposure to overflight noise. If the structure has been made into condominiums, issues may arise about exterior consistency of design for treat- ments, depending on each owner. Row houses are similar except horizontally stacked. Issues of exterior consistency need to be negotiated before design proceeds. F. Beach Bungalow As opposed to arts and crafts style bungalows, which can be very detailed and historic, the beach bungalow (see Figure 5.6) is a minimalist box with a flat roof. The flat roof is often low and is a direct noise path potentially requiring treatment. G. Historic Homes Historic homes (see Figure 5.7) come in many styles across the country and are discussed in Chapter 6. Issues may include custom window and door shapes, intricate detailing for product installation, and design restrictions due to historically significant characteristics. Figure 5.6. Beach bungalows. Figure 5.7. Historic homes.
82 Guidelines for Airport Sound Insulation Programs H. Additions While not a style, additions to houses (see Figure 5.8) require special attention for noise paths. Additions can be built of lighter-weight construction than the rest of the house. Closer inspec- tion of the houses during assessment will help determine whether any exterior walls or ceil- ings consist of a less-than-normal assembly of materials and whether more in-depth structural inspections will be necessary. It is also cautioned to review building permit records to see if additions were inspected. Unpermitted additions may require additional coordination with the local building department for the program to pull permits for the sound treatments. These types of enclosed spaces will be evaluated to determine if they meet the criteria for year-round habit- ability, including adequate and permanent HVAC; construction materials and assemblies that meet standard building practices; and foundation, wall, ceiling, and roof assemblies that meet code requirements. Where additions do not meet standards for year-round habitability, evaluate noise paths into the main structure for treatment. Finally, it is important to verify that any area of the house that is being considered for sound insulation meets the best practice recommenda- tions discussed in Section 5.2.7. 5.2.3 Developing Treatment Strategy Understanding where aircraft noise intrudes into a building means understanding the build- ingâs exterior envelope (see Figure 5.9). From the foundation to the walls to the roof, wherever air enters a building, noise can be transmitted. Thanks to several decades of experience, the sound insulation industry has a body of knowledge regarding noise paths into most residential structures. Sources of noise penetration include: â¢ Fenestration openings (windows, doors, and skylights), â¢ Walls, â¢ Roofs, â¢ Attics and crawl spaces, â¢ Chimneys and other exhaust openings, and â¢ HVAC systems. Treatment of these noise paths involves two primary methods. The first involves dissipation, which reduces the noise energy through baffles and turns in ductwork. Where air flow cannot be eliminated, such as in mechanical systems and attics, noise energy dissipation through baffles Figure 5.8. Additions.
Design of Architectural Treatment Strategies 83 and ductwork works well. The second treatment method involves providing physical barriers to noise, usually in the sequence of (1) mass, (2) air space, and (3) mass. This applies to many build- ing assemblies, such as walls, roofs, and glazed systems. Glazed openings are treated using this sequence to reduce noise without making products that are too heavy. Mass is provided by glass that is thicker than standard materials (e.g., laminated glass) on either side of approximately 1 in. to 2 in. of trapped air space (e.g., between insulating glass). More information on fenestra- tion products is available in Chapter 9. It is important in the pilot phase of a program to include treatment protocols for treating noise paths other than windows, doors, and HVAC systems. Until the first structures are assessed, impacts from those paths may not be discernible. Per PGL 12-09, authorization to treat such noise paths must be secured in advance, making it imperative that treatment designs are included in the initial submission of the program policy and procedure manual to the ADO: Noise insulation measures are limited to window and door replacement, ceiling insulation, caulking, weather stripping, and central air ventilation systems. The use of other measures is not allowable unless the ADO has approved the use of the measures in advance.4 Treating windows and doors addresses the major source of noise into most homes. There are three principal ways to treat fenestration openings: 1. Repair and upgrade existing windows and doors with new glass, weather stripping, caulking, and so forth. 2. Add secondary storm products to the existing openings. 3. Replace the product with acoustically rated products. PGL 12-09 limits noise insulation measures to âspecific items.â5 Except for ceiling insula- tion, wall and ceiling treatments are not included in the list of treatments cited. If achieving a 5-dB reduction is an absolute, then in some instances, wall and ceiling treatments will be required. The PGL allows for these as âother measures,â subject to approval in advance by the Courtesy the Jones Payne Group, Inc. Courtesy Wyle Laboratories, Inc. Figure 5.9. Noise paths. 4 U.S. DOT, FAA, PGL 12-09, August 17, 2012. Attachment 1, Â§812 (c)(1),Table 1, p. 1-4. 5 U.S. DOT, FAA, PGL 12-09, August 17, 2012. Attachment 1, Â§812 (c)(1),Table 1, p. 1-4.
84 Guidelines for Airport Sound Insulation Programs ADO. A design/policy manual for a program that specifies when wall and ceiling treatments are needed may be sufficient advance notice if the design manual is approved by the ADO. Program sponsors and consultants are advised to consult with their local ADO for further clarification regarding this issue. While it is possible to achieve noise reduction by refurbishing existing windows and doors, most programs choose complete replacement of fenestration with acoustically rated products. (Note: Refer to Chapter 6 for guidance on where replacement of windows and doors in historic structures is counter-indicated.) This provides greater confidence in the results and longevity of the sound insulation. The other potential sources of noise penetration require evaluation for their conditions and contribution to noise. The following sections will discuss them in further detail. 5.2.4 Treatment of the Residential Building Envelope Once program standards and typologies are established from the windshield survey, treatment options can be designed. Architectural differences in housing styles across the country require considerable thought to make products visually appealing while meeting sound reduction goals. Local communities, especially historic districts desiring to maintain neighborhood character, will often want to review the style of products a program is planning to install. A. Walls While windows and doors are an obvious source for noise penetration into a building, the walls contribute to or detract from noise reduction as well. Per the acoustic principles discussed in Chapter 4, mass (density, weight) plays an important role in reducing sound transmission. Wood- framed homes are composed of the lightest mass construction materials of the standard American home. If the wood framing and siding does not conform to normal construction standards for materials and assembly, the walls potentially become a noise path. Concrete block or brick faÃ§ades provide significant mass, thereby reducing the possible need to treat lightweight walls. To achieve the NLR necessary to meet the acoustic goals, the first step is to determine the STC or NLR performance of the main structure of the building. The great majority of homes in the United States meet the minimum standard to achieve an STC of 37â40 in the wall construction. The diagram of a wall section in Figure 5.10 shows the minimum construction needed to proceed in sound insulation in the 65-dB to 70-dB DNL without consideration of treatment to the walls. Figure 5.10. Minimum STC 37â40 wall.
Design of Architectural Treatment Strategies 85 Without insulation, the wall performs at 37 STC, and with insulation it can achieve up to 40 STC. If either the interior or exterior wall does not have the minimum Â½-in. material with good mass properties, or the stud cavity is less than 3Â½ in., the wall may not perform to the standard neces- sary to create a consistent envelope when STC 38â40 fenestration products are installed. Closer inspection of homes during assessment will determine whether any exterior walls consist of a less-than-standard assembly of materials. Structures in 70-dB to 75-dB DNL may have higher STC needs that should be determined in conjunction with the acoustical consultant. Wood-frame construction is susceptible to wind and termite damage. Investigate for any evi- dence of structural issues before adding additional load of drywall or other materials. B. Ceilings Evaluating noise impacts through roofs is an important component of providing sound insu- lation. Much like walls, the roof/ceiling needs to have a minimum STC performance to provide a consistent envelope before considering the impact from fenestration openings. The roof/ceiling assembly requires evaluation for its contribution to noise intrusion. A good discussion of ceiling considerations is in the 1992 guidelines.6 In the early practice of some programs, flat or monolithic roofs were built up with new roofing as an insulation treatment. Given wind and structural load issues, programs have developed interior treatments as an alternative. Programs need to establish the prevalence of ceiling impact and design effective treatments with the acoustical consultant. The following list is a sampling of the ceiling/roof conditions that need to be assessed as potential noise paths: â¢ Lightweight construction materials, such as tin or Celotex ceilings or material with less mass than Â½-in. drywall/plaster. â¢ Cathedral ceilings with no enclosed attic space above. â¢ Attic spaces that are uninsulated or that have large ventilation grilles. â¢ Flat, monolithic roof/ceiling systems without attic space or air space above. (Concrete flat roofs may be an exception.) C. Attics Attic spaces are considered unfinished space immediately below the roof structure. Various types of construction will contain openings into attics that create noise paths. These openings will need to be evaluated for their impact on the noise level in habitable space. A good discussion of attics and their acoustic impact is in Chapter 3 of the 1992 guidelines.7 Insulation. Where there is access into attic spaces and existing thickness is less than 6-in., provide insulation to the floor of attic spaces up to a maximum of 6 in. No insulation is required for floor spaces covered with plywood or flooring material providing adequate acoustical mass. No insulation will be provided where access into attic space does not exist and openings would have to be cut into the ceiling. Where the program is adding insulation, venting will need to be provided to meet code requirements. If existing venting exceeds code minimum sizes, vents may be acoustically baffled on a case-by-case basis. Swinging Doors. Swinging doors to an attic or eave space should be replaced with a fully weather-stripped interior solid core door if the existing door does not meet acoustical guidelines. Install storm windows to existing windows to create a uniform, consistent appearance to the house. 6 U.S. DOT, FAA, Report No. DOT/FAA/PP-92-5, Guidelines for the Sound Insulation of Residences Exposed to Aircraft Opera- tions, October 1992. 7 U.S. DOT, FAA, Report No. DOT/FAA/PP-92-5, Guidelines for the Sound Insulation of Residences Exposed to Aircraft Opera- tions, October 1992.
86 Guidelines for Airport Sound Insulation Programs Attic Hatch. If the existing hatch is tight fitting and consists of minimum Â¾-in. plywood or equal material, provide weather stripping around the perimeter only. All other hatches are to be replaced with a fully weather-stripped hatch consisting of Â¾-in. plywood, Â¾-in. sound deaden- ing board, and Â½-in. plywood. If mechanical equipment is located in the attic space, the access opening may need to be enlarged to meet code requirements. Pull-Down Stairs. All existing pull-down stairs are to have a sound-insulated enclosure. If the pull-down stair is in disrepair or will not allow the installation of the sound-insulated enclo- sure, replace the pull-down stair and install the sound-insulated cover. D. Miscellaneous Openings Any direct opening that connects the exterior to the interior needs to be reviewed as a noise path. This can include mail slots through the wall or door, through-wall fan vents that are not ducted, milk delivery slots in older homes, and unit ventilators. All of these items will need to be removed and the opening sealed with wall materials or new doors. Fireplaces require special consideration. While each fireplace system, especially manufactured units, will need to be evalu- ated, common treatments include glass doors on the firebox and a chimney-top damper. Install- ing glass doors on manufactured units may be prohibited by the manufacturer, particularly as it pertains to heat buildup in the firebox. 5.2.5 Treatment of Residential Fenestration As discussed throughout these guidelines, building codes are adopting increasingly stringent energy efficiency requirements. These requirements extend to replacement of residential fen- estration. When determining treatments and selecting products, be aware of solar heat gain coefficients and U-values. Specific to the climate region where the program is located, these requirements affect the type of glass that may need to be put in the windows and the overall energy performance of the assemblies. A. Windows Choosing a window for a residential sound insulation program involves investigating many areas of performance. Some questions regarding performance that most homeowners will be concerned with are: Will it be a quality product that will hold up over time? How is it going to look in my home? Can I clean it? What do I have to do to maintain it? Can I still fit my plants on the window sill? Will it really reduce noise? Other criteria that will directly affect homeowners are installation and aesthetics. How easy is the window product to install? How much of the wall needs to be disturbed to get a good installation? The answers to these questions often depend on the construction of the house. Not all houses were built with the thought of easy window replacement, but careful planning can minimize the time and cost of installing the right product. Programs should also take into con- sideration a homeownerâs maintenance costs, the most common of which comes from replacing acoustical glazing should it be broken. If a program uses a window with expensive, laminated, argon-filled glass to meet the performance criteria, it is unlikely that the homeowner will replace the acoustical glazing with identical material. The issue of aesthetics is crucial to many homeowners since it affects the value of their prop- erty. A colonial house with traditional windows may be easier to retrofit with replacement win- dows than a modern beach house with huge expanses of glass. Introduced in the 1990s, acoustic vinyl and vinyl composite windows, specifically designed for residential sound insulating programs, have become the preferred window type for many programs. Some programs use dual metal windows; however, the increasing energy performance
Design of Architectural Treatment Strategies 87 required in many code jurisdictions will require careful review to confirm if they will meet code requirements for U-values, condensation resistance, and thermal performance. A detailed examination of acoustical windows is in Chapter 9. The use of secondary glazing products, or storm windows, can help create the conditions essential for aircraft noise reduction. Wood replacement windows with the addition of secondary storm windows are offered in a third of all programs and have been approved for application in historic properties. Residential windows have a standard variety of opening configurations, including double hung, sliding, projecting, and fixed. There are some variations on this that are available in high- quality custom windows, such as pivot-hinged windows, but these options are not available in the U.S. acoustical market. There are also some regionally specific window types, such as jalousie windows in coastal regions, that cannot be replicated in acoustic windows. In addition to opera- tional configurations, nonrectilinear shapes require review for product availability. Custom or curvilinear shapes are difficult to manufacture in vinyl and expensive in other materials. In some programs, home security is an issue that can affect the scope of work for installation of new products. When homeowners have protective metal grilles on windows, programs have to evaluate the life-safety code requirements for ease of egress without special tools or knowledge of how to operate the window. In other words, during an emergency, a window must be easy for occupants to exit through or for firefighters to enter. Programs take various approaches to this issue. For the window hardware itself, most programs provide standard industry hardware. For protective grilles, some programs remove them without replacing, leaving the resolution to the homeowner, while other programs adapt grilles with emergency hardware or install new grilles with current, code-compliant hardware. With the general increase in depth of the acoustic win- dow product, reusing the existing grilles can be problematic without adjustment. There are many details involved in treating windows, such as color, sizing, decorative elements like mullions and grids, art glass, garden windows, sidelights to doors, installation details, and the likelihood that window treatments will require adjustments to be reinstalled. Homeowners will have concerns about these specifics that the program needs to address and record in its PPM. B. Doors Each successful sound insulation program needs to consider what types of doors are archi- tecturally appropriate to the neighborhoods where they will be applied and look carefully at what homeowners have selected. The technical challenges of sound level reduction can then be resolved with door types and styles that homeowners will see as appropriate. There are three basic primary entrance door types used in sound insulation projects: steel/metal, flush wood, and wood panel (stile and rail). Fiberglass doors, while increasingly popular in home renovations, do not currently provide the necessary acoustical performance criteria for SIPs. Many homes have French or patio doors of various types, such as sliding, single hinged, and hinged pairs. Most acoustically rated doors use mass as the primary method of reducing sound transmis- sion. Where mass alone cannot achieve the goal or where those options are not agreeable to homeowners, a successful solution is installing a primary and a secondary door. Secondary doors create an air space with the primary door and a consequent decoupling between the two doors. This significantly increases the sound transmission loss of the door opening. A third option is to eliminate flanking sound paths with good gasketing. All primary and secondary doors must have excellent gasketing and weather stripping to be effective. While stand-alone acoustical doors without glazing are offered in many programs, many pro- grams also provide custom-quality doors with insulated glass installed with secondary storm doors. Only a handful of manufacturers make STC-rated flush doors that have a high enough
88 Guidelines for Airport Sound Insulation Programs STC rating to be used without a secondary door. Homeowners are more receptive to this stand- alone product in regions where storm doors are not commonly used. Flush or flat doors do not complement the architectural style of houses in many areas of the country. Panel doors are more compatible to the architecture found in older communities and cooler climates. To remedy this problem, applied moldings can be added to flush doors to simu- late the look of panel doors. Steel doors are available with a wide range of STC ratings, including the very high ratings needed for recording studios and other special uses. Steel doors are available with STC performance in the ranges needed for SIPs, but they are often not very residential in appearance. Some manufacturers make an embossed or pressed-in panel to simulate the look of a panel door or apply moldings to the surface of a flush door. Acoustically rated steel doors for exterior use are a solid choice in situa- tions where a secondary door cannot be installed and where a fire rating is needed. Wood Panel Doors (Stile and Rail). In the regions in which these are used, they are custom- arily installed with secondary doors. Some wood panel doors have not been laboratory-tested for STC rating, and generally none have the combination of primary and storm doors mounted together. Since the primary and storm doors are usually made by different manufacturers, there is little laboratory testing of the two products as a single assembly. Nevertheless, sound insula- tion programs have found through extensive field testing that the necessary noise level reduction for door openings can be achieved using high-quality residential products with an intervening air space. This field testing has shown that panel doors can be used for SIPs when they are con- structed with wood of a density and thickness that is greater than standard raised panels installed between stiles and rails. Figure 5.11 shows two door sections. The door on the left has been accepted for use in SIPs. Note that the raised panel is thicker in both the main section and in the edge that joins with the stiles and rails. Figure 5.12 shows the installation with full-lite secondary products over the door and sidelights. The door must be fully gasketed, and glazing should be insulated glass. This type of construction is available from a number of fabricators. This solution nicely meets the needs of aesthetics, acoustics, and durability. Figure 5.11. Wood panel, sound- insulating door compared to builderâs- grade panel door.
Design of Architectural Treatment Strategies 89 Flush Wood Doors. Flush wood doors for exterior use often require that the doors be pro- tected from the weather with overhangs or secondary doors. If these conditions cannot be met, a warranty may not be available from the manufacturer. Some programs instead purchase an extended warranty from the installing contractor. Occasionally homeowners who select wood doors want them stained and varnished. Unfortunately, even the best exterior varnishes have a short life and must be reapplied at least every other year. Several programs have eliminated stained finishes due to their climate and maintenance concerns. Patio Door. Patio door models suitable for sound insulation programs are available in wood, aluminum, swinging, and sliding. The choice is largely driven by the prevalent architec- tural styles and homeowner preference. Only a few aluminum doors are manufactured with the STC ratings required to meet the needs of a stand-alone, single unit in a sound insulation program. Where an alternative appearance is desired, a secondary door is required. There is a limited selection of sliding aluminum secondary doors available that will provide the necessary noise level reduction through decoupling. These can be used with in-swinging hinged and slid- ing patio doors of various types. C. Fenestration Installation Considerations and Methods Sound insulation programs are by nature retrofit or replacement programs. Since all of the products will be replacing existing windows, it is important to consider the constructability characteristics of these replacements. How well does the window work as a replacement? Is it available in custom sizes? How thick is the frame, and will it fit in the walls? A 6-in.-deep window will not fit in a standard wood-frame wall without special modifications to the opening. Does the window have installation extrusions like nailing flanges or snap-on trim? If a home is occupied, how quickly can the windows be installed to minimize homeowner inconvenience? Proper Installations. Proper installations begin with good design of flashing details incor- porated into the projectâs construction documents. Information on proper flashing is found in a number of sources, such as the Sheet Metal and Air Conditioning Contractorsâ National Association (SMACNA) Residential Sheet Metal Design Guide, manufacturersâ published data, Figure 5.12. Secondary products over door and sidelights.
90 Guidelines for Airport Sound Insulation Programs and architectural graphic standards. ASTM E2112, Standard Practice for Installation of Exterior Windows, Doors, and Skylights, has been developed by industry consensus to address the qual- ity of fenestration installation and includes recommendations about proper flashing. Architects should use these standards and guidelines to produce suitable designs. Of course, the best design poorly executed will not ensure the needed acoustic performance or homeowner satisfaction. Programs reduce the risk of improperly installed products by imple- menting construction quality control procedures. On-site observation services provided by qualified project representatives are the best defense against deficient installations. Observers can detect nonconforming work and direct the contractor to correct it. Qualified contractor personnel improve the quality of installations as well. Some programs have required contractors to use installers trained under the provisions of the American Architectural Manufacturers Asso- ciation (AAMA) InstallationMasters Training and Certification Program.8 This program is based on the requirements of the ASTM E2112 standard. InstallationMasters is a nationwide training and certifications program that was prompted by the Building Environment and Thermal Enve- lope Council (BETEC) through the U.S. DOE and developed by the AAMA. Designed for new construction and replacement installers of windows and exterior glass doors in residential and light commercial markets, the InstallationMasters program is an important tool offered across the country. Detailing the Fenestration Installation. This falls into two broad categories, retrofit (pocket for windows, leaf for doors) installation and rough opening or unit installation. Retrofit instal- lations are used when the replacement acoustic product will fit easily into the existing opening with little modification to the window frame or wall. This is common in older, Eastern and Mid- western houses where window sashes were designed to be replaced without removing the entire frame. Retrofit installation of windows saves time, is less disruptive to homeowners, and allows less opportunity for construction issues. Presuming that the existing frame is in good condition, the installation needs to include insulation and sealants to prevent air and noise infiltration. Where window weight pockets exist, they need to have weights removed from the wall and have the remaining void insulated to increase acoustic performance. Figure 5.13 shows a typical jamb section at a pocket install for a vinyl composite window. Rough opening or unit installations are used when the fenestration will not fit easily into the existing window frames or wall depth or when the conditions of the opening are deteriorated or not square and will not allow for proper insulation and sealant installation. Construction methods vary regionally, and window installations typify this difference. Recent construction practices, such as installing windows with nailing fins or using drywall surrounds to embed the window, make window replacement more difficult, often necessitating taking out the window trim/surrounds and frame back to the wall studs. This is considered the rough opening. Figures 5.13 and 5.14 are sche- matics for wood-framed walls; there are many types of walls. The important differences in adapting regional window installation details to sound insulation are: â¢ Overlap of materials to mitigate sound penetration, â¢ Proper insulation and caulking installation, and â¢ Consideration of wall thickness and trim detailing due to thicker and heavier products. Replacement windows should be sized to match existing openings. All windows should be custom manufactured to meet the specified installation detail rather than being an off-the-shelf, standard size. The enlarging or downsizing of openings is not recommended except for specific 8 See InstallationMasters USA website, http://www.installationmastersusa.com.
Design of Architectural Treatment Strategies 91 construction and life-safety egress requirements, such as when the window will be too small to allow for fire egress or the window exceeds the minimum or maximum dimensions of product availability. For doors, the rough opening/unit or full-frame replacement has become the preferred method in most cases due to the reliability of the install compared to trying to adjust a new door to a frame that may be out of square or skewed. Further information about installation is available in Sections 9.4 and 11.3.2. D. Hurricane Impact Hurricane impact code requirements are becoming more prevalent along the East and Gulf Coasts; however, they vary greatly depending on the wind speed and impact resistance require- ments for the region. The first step in establishing the programâs design requirements is to estab- lish the maximum wind load for the project area. This is determined by referencing the stateâs approved building code map that describes expected wind loads for any given area of the state. Once the wind load is defined, the design pressure needed9 to withstand the wind load can be determined. Design pressure is one of the components of the AAMA performance standard used in the construction product industry to define classes of products. Determining the class of products sets the minimum quality standard for the program. Figure 5.13. Retrofit installation jamb detail of vinyl composite window. 9 See ASCE 7-02, Minimum Design Loads for Buildings and Other Structures.
92 Guidelines for Airport Sound Insulation Programs It is important to note that design pressure requirements are separate from impact resistance requirements (another important performance requirement) and that the strength of window and door product frames and anchoring must respond to the designated wind load conditions. Areas subject to hurricane impact are also prone to flooding, which can trigger an additional project work requirement that all mechanical equipment, including condensers and electric feeds, be raised above stipulated worst-case flood conditions. There are two primary means of protecting the openings of homes in hurricane zones: impact-resistant products and physical barriers, such as shutters or removable impact panels bolted over windows and doors. Impact resistance requirements are very specific and extensive because doors and windows need to withstand the impact of small and large projectiles fired at specific velocities. While many manufacturers are developing window and door products to meet impact resistance standards, the focus has been on commercial rather than residen- tial products. Impact resistance was added to the code as a way of ensuring that the exterior envelope of structures remained intact without the installation of large, heavy protection. The products, including glass, are essentially designed to bend but not shatter, thereby minimizing interior wind and water damage to the structure. Nevertheless, it is not unusual for windows and doors to be damaged. Given the expense of replacement and the limited availability of acoustically tested products, impact-resistant windows and doors are relatively new to sound insulation programs. In some hurricane zones, the preferred protection for impact resistance is shutters or metal panels placed over windows and doors. If one adopts this design approach to deal with impact resistance, an important requirement is to maintain the required deflection distance between the shutter and Figure 5.14. Rough opening/unit installation jamb detail of vinyl composite window.
Design of Architectural Treatment Strategies 93 the acoustical door or window product, which are constructed with deeper frames than most non-acoustical residential products. Many frames are between 4.5 in. and 5 in., which allows room for deflection space when installed in a typical concrete masonry unit wall. In a typical wood-frameâconstructed wall, however, accommodation must be made. It should be noted that in high-velocity hurricane zones, such as South Florida, air and water infiltration requirements are higher than the national requirements. This may limit the number of acoustic products available. Balancing wind and acoustic performance requirements can be achieved by combining acoustically rated products with hurricane-resistant products. This is a good way to provide homeowner-friendly treatment options in hurricane-prone regions. For example, an out- swinging full-lite impact-resistant door can be paired with an acoustically rated in-swinging prime wood or metal door and meet or exceed noise reduction requirements. Cases where there are products that meet both impact and sound insulation needs are relatively few, thereby requiring the architect to be creative when writing specifications and selecting products that meet all the performance requirements. 5.2.6 Encountering Hazardous Materials The presence of hazardous materials such as lead and asbestos may affect eligibility for inclu- sion in SIPs, as well as treatment approaches for certain building components. Under current federal and state regulations, the handling and removal of hazardous materials from residential structures in connection with building rehabilitation- and renovation-type projects is clearly defined. The handling of hazardous materials in the program is limited to areas where the acoustical and associated improvements are installed. Two primary hazardous materials, asbes- tos and lead paint, are often encountered in homes. In addition to federal requirements, each state and municipality will have abatement procedures for public work. Working with a local hazardous materials consultant to format policies and procedures is an important part of pro- gram formation. Asbestos. Asbestos-containing materials encountered in the sound insulation process may be removed, altered, or disposed of under the construction contract. These may be found as part of the existing HVAC systems or in transite-type asbestos siding materials, which may be affected by window and door replacement. Work performed affecting these materials must be carried out in conformance with all applicable federal, state, and local regulations. Lead Paint. Lead paint can be found in wood surrounding windows and doors as well as other potential areas affected by SIPs. If lead paint is present, it does not exclude the residence from the sound insulation program. If, however, a homeowner has been issued an order to de- lead by a responsible authority, the residence may need to be placed on hold until all de-leading activity has been completed and certified by the responsible oversight agency. Mold and Radon. Mold and radon, although not addressed as hazardous materials as such, can pose environmental health problems. Specific to the climate of each SIP, programs will need to develop policies on appropriate actions to take if these items are discovered in the structure. Chapter 7 addresses the indoor air quality and ventilation requirements of homes in SIPs. Appropriate federal, state, and local regulations must be followed where the installation of acoustical treatments or associated treatments may disturb known or suspected lead-paintâ containing materials. The U.S. EPAâs web page for the Lead Renovation, Repair, and Painting Program states that: Common renovation activities like sanding, cutting, and demolition can create hazardous lead dust and chips by disturbing lead-based paint, which can be harmful to adults and children. To protect against
94 Guidelines for Airport Sound Insulation Programs this risk, EPA requires contractors performing renovation, repair, and painting projects that disturb lead- based paint in homes, child care facilities, and schools built before 1978 must be certified and must follow specific work practices to prevent lead contamination.10 It is important that contractors working on SIPs are compliant with the EPAâs Lead Renova- tion, Repair, and Painting Program. 5.2.7 Building Codes for Residential Buildings The first step in evaluating building codes for sound insulation is to determine which ver- sions of codes are in effect for each jurisdiction affected by the program. Each state, county, and municipality may have different legislation establishing jurisdictional power to set codes. Determine if there are local code requirements or zoning provisions that supersede the model building codes adopted by the state. Local provisions are particularly important when it comes to interpreting codes for renovation and can place additional performance require- ments on residential SIPs. Code interpretation is largely dependent on whether the local authority having jurisdiction rules that the sound insulation treatments constitute a renova- tion of a major system rather than being simply a repair or replacement of an existing building component. In some jurisdictions, installation of acoustical doors and windows is considered to be a major system renovation that triggers other work requirements. Installing HVAC systems requires a building permit in most jurisdictions and is considered a major system renovation in a residence. PGL 12-09 states, âIf it is determined in the course of designing a sound insulation project that a building needs improvements in order to conform to local building codes, only the costs of sound insulation are allowable.â11 The intent of this statement is to limit the responsibility of SIPs to correct a structureâs outstanding maintenance issues using AIP funds. In order to con- form to local building codes, installation of code-conforming acoustical treatments is required. When a building was properly built under the prevailing code of its time, updating aspects of the structure to accommodate the installation of sound insulation treatments may be accept- able. For example, if a bedroom window opening has to be enlarged to meet egress require- ments per local codes, the cost of creating a larger opening is an allowable program expense. Or, if the code requires impact-resistant windows or storm shutters that must remain a defined distance away from thicker windows, thus requiring modification of the window opening, this is an allowable cost. However, there are many situations where it is difficult to separate the acoustical treatment from the code-conforming installation of the treatment. Program spon- sors and consultants are advised to consult with their local ADO for further clarification regarding this issue. A. Defining Habitable Space Previous chapters in these updated guidelines have discussed the issue of treatment eligibility based on acoustical factors. Not every space that qualifies for treatment based on acoustical fac- tors necessarily qualifies for treatment, depending on the program definition of habitable living space. Not every SIP has had the same criteria for determining what spaces within a residence are habitable. This is due to three factors: (1) varying interpretations of building codes on what constitutes âhabitable spaceâ or âliving space,â (2) a lack of specificity in previous versions of the guidelines, and (3) community expectations for treatment consistency in each home. 10 Renovation, Repair, and Painting Program â Related Information, United States Environmental Protection Agency, accessed January 2012, http://www.epa.gov/lead/pubs/rrp.htm. 11 See note 4. Attachment 1, Â§812 (c)(3),Table 3, p. 1-8, 1-9.
Design of Architectural Treatment Strategies 95 The 1992 and 2005 versions of the guidelines attempted to address this issue by providing guidance for the treatment of habitable rooms and living spaces. Unfortunately, code defini- tions of living space and habitable space are not the same. Specifically, the definition of a habit- able space excludes âbathrooms, toilet rooms, closets, halls, storage or utility spaces, and similar areas,â whereas the definition of living space includes spaces for âbathing, washing, and sanita- tion purposes.â The full definitions of these terms as provided in the 2009 and 2012 versions of the IRC are provided in the following. âHabitable Space â A space in a building for living, sleeping, eating, or cooking. Bathrooms, toilet rooms, closets, halls, storage or utility spaces and similar areas are not considered habitable spaces.â12 The concept of habitability establishes standards for building planning, general health, life safety, egress, and minimum room dimensions. This forms the key reference for determina- tion of which spaces within a home are eligible for treatment. While this habitability definition excludes bathrooms, toilet rooms, closets, halls, or storage or utility spaces, the code further defines âliving spaceâ as: âSpace within a dwelling unit utilized for living, sleeping, eating, cooking, bathing, washing, and sanitation purposes.â13 Living space as defined in the International Mechanical Code includes any space that receives HVAC, including hallways, bathrooms, laundry rooms, and foyers. Living space identifies the total occupiable portion of a building that requires appropriate engineered systems for comfort and livability. Note: Therefore, for the purposes of SIPs, the FAA limits architectural treatments to code- defined habitable rooms, while mechanical treatments must encompass the code-defined living space to meet code requirements. B. Determining Architectural Treatment Eligibility Some programs have used the definition of âhabitable spaceâ to create narrow parameters for treating only those rooms used for living, sleeping, eating, or cooking. Other programs have used the definition of âliving spaceâ to treat all interior spaces. FAA directs that: Eligible projects may include noise insulation of only the habitable areas of residences such as living, sleeping, eating, or cooking areas (single family and multifamily). Bathrooms, closets, halls, vestibules, foyers, stairways, unfinished basements storage or utility spaces are not considered to be habitable.14 Supplementary treatments for architectural consistency to areas that the FAA determines ineligible for treatment cannot be reimbursed under AIP funding. Programs have found that homeowners have challenged policies that create inconsistency in their homeâs exterior appear- ance or in sound insulation performance by not having hallways, laundry rooms, or bathroom fenestration treated. Consult with the local ADO regarding rules for applying local funding to provide consistent treatments. C. Evaluating Habitability The great majority of homes built to industry standard practices will meet code requirements for habitability. Dwellings built prior to codes or ones that have been altered, built onto, or 12 International Code Council, Inc., International Mechanical Code. 2009, 2012. 13 International Code Council, Inc., International Mechanical Code. 2009, 2012. 14 See note 4. Attachment 1, Â§812 (c)(3),Table 3, p. 1-9.
96 Guidelines for Airport Sound Insulation Programs subdivided will often require more careful assessment of physical conditions, which is the basis of code determinations of habitability. Table 5.2 is based on the 2009 IRC and provides a list of physical conditions relevant to SIPs that should be evaluated in each home to determine whether spaces that are acoustically eligible for treatment also meet code habitability requirements. Remediating conditions in spaces that make them nonhabitable, such as inadequate room dimensions, improper heating or sanitation, or insufficient light and air, can require sig- nificant effort. Any deficiencies in these basic building standards that are not corrected may cause difficulties with building inspections during permitting and construction and, as such, should be addressed before treatment recommendations are finalized and treatments are bid. Many programs either disqualify homes or specific rooms within homes with such issues or allow the homeowner the opportunity to correct the issues and return to the program at a later date. Code Issue Minimum Code Standards Egress Requirements For rooms used for sleeping purposes Must have one means of egress that meets code minimum dimensions for clear opening, max sill height with no obstructions that impair egress. Ceiling Height, Material, and Structure Height Minimum 7â0â. Impediments Not less than 6â4â. Adequacy of structure Must support barrier materials. Insulation and venting Sufficient to meet code minimums. Room Dimensions For dwelling unit Must have one room not less than 120 ft2. For defined âhabitableâ rooms in units Not less than 70 ft2 and not less than 7â0â in any dimension. Indoor Air/Light Quality Minimum window area of 8% of floor area per room for light with 4% operable or vented by mechanical means Heat Determine winter design temperature. If qualified, must achieve minimum 68Â° F (cannot be space heaters). Mechanical Ventilation Combustion air for fuel burning heating Must meet code requirements. Carbon monoxide and smoke detectors Must meet code requirements. Electrical Defective wiring Must meet code requirements. Noncompliant but nondefective Can be grandfathered. Foundation Barrier skirting Equivalent to min Â½-in. plywood with venting. Structurally sufficient Must be adequate to meet both existing and acoustical treatment loads. Walls Insulation As required to meet code. Interior wall material Equivalent to min Â½-in. gypsum board. Exterior wall material Equivalent to standard sheathing and siding. Floor Continuous barrier material Equivalent to min 5/8-in. plywood; no gaps. Insulation As required to meet code. Windows Prime windows Maximum air infiltration â 0.50 cfm/lin ft crack perimeter. Doors Prime door Maximum air infiltration â 1.25 cfm/ft2. Adequate landing Min. 36 in. both sides of door. Other Laundry and toilet rooms Natural or mechanical venting as required by code. Mechanical room and garage Fire separations and venting as required by code. Table 5.2. Potential habitability issues based on 2009 IRC and best practices.
Design of Architectural Treatment Strategies 97 D. Code Requirements That Affect Treatment Recommendations The consultant team will need to conduct a code review as an essential part of program start-up. This review will need to include consultation with the local building authority on code interpretation as it applies to the intended program treatments. During property assess- ments, the design team will look for and take note of existing conditions that do not conform to code and may potentially affect treatment recommendations. When surveying existing conditions, there is no implied or expressed intent to conduct a detailed code review and analysis or to identify all nonconforming conditions that may be present in the residence. The scope of the survey is limited to identifying any conditions that may affect treatment recom- mendations at a given location or for the residence as a whole. The intent of the program is not to undertake extensive remedial measures to correct outstanding deficiencies to allow implementation of the acoustical treatments. The program focuses only on the mechanical, electrical, structural, or code issues that will affect proper installation of the sound insula- tion products as recommended. The responsibility for resolution of these deficiencies may belong to the property owner, depending on the negotiated environmental impact study or local program funding. Code-required items to be assessed include: 1. Does the door opening conform to required dimensions of height and width? Are there as many doors as the code requires? Some jurisdictions require two egress doors from a residence. 2. Is the height of threshold at egress doors less than allowed by code so that they are not a trip hazard? This can be a particular issue at basement openings through foundation slabs and walls and sometimes at doors out to balconies. 3. Does the door open to a code-conforming landing? Is that landing in sound condition? (See Figure 5.15.) Figure 5.15. Door landing in poor condition.
98 Guidelines for Airport Sound Insulation Programs 4. If new HVAC systems are being installed, does the electric panel meet the requirements for the work to proceed? While the wiring for the whole house is not checked, are there nonconform- ing conditions for elements of the system that the program will be altering? 5. Life safety items that local code officials often require as part of SIPs are smoke detectors and egress windows. a. If a home does not have smoke detectors, it is often required that SIPs install them. The consultant team should confirm with local building officials if they need to be hard wired or if battery-operated ones are acceptable. b. The requirements for bedroom window sizes for access by firefighters have increased decidedly since most of the homes in programs were built. Many homes in the 1960s were built with then-popular long, high ribbon windows. These windows are now too high from the floor (>44 in.) and too small (<5.7 ft2) to meet current egress standards. Many jurisdictions require SIPs to enlarge the openings and lower sills to meet emergency requirements, whether the walls are concrete block, wood frame, or brick. 5.2.8 Developing Program Standards As a publicly funded activity, sound insulation programs treat single residences within the context of neighborhoods. This means that while each home and homeowner is unique, they must be treated within the framework of a program with well-defined guidelines and standards that are equitably applied. The most successful programs are those that provide consistent treat- ments while including a rule set for addressing unique issues. This can be an important asset when homeowners believe neighbors have received benefits they have not. Chapter 3 deals with various methods of community outreach, while the specific program standards that outreach will communicate are discussed throughout these guidelines. Specific mention needs to be made here about a particular challenge inherent in communicating pro- gram standards, which is communicating a consistent message throughout the process. Pro- grams vary in how they accomplish this, but a couple of methods are: 1. Programs can have a single point of contact (a homeowner liaison, which can be either a sponsor employee or a consultant) for speaking with homeowners. This reduces the potential for inconsistent messages. This person must be able to address all aspects of the program. 2. Programs should prepare written scripts for program personnel to deliver at the appropriate stages in the process. Practice these talks and review potential ramifications of not staying on message. Homeowners are neighbors and will compare what they are told by program representatives. As the program develops its standards, being mindful of how they will be communicated and perceived will facilitate community participation. A. Establishing Program Protocols with the ADO PGL 12-09 speaks to providing conformity of treatment at the neighborhood level: To ensure community support, it may be reasonable to include provisions for neighborhood equity in a noise insulation project. In these cases, the sponsor develops two sets of noise insulation packages. The standard noise insulation package will be prepared for residences that meet the interior noise criteria. A second package will be prepared consisting of other improvements such as caulking, weather stripping, installation of storm doors, or ventilation packages for residences that are not experiencing interior noise 45 dB or greater.15 15 See note 4. Attachment 1, Â§812 (d)(1),Table 4, p. 1-11.
Design of Architectural Treatment Strategies 99 However, use of this secondary protocol is significantly restricted: In order for grant funding to be available for the secondary package, participation must be limited by FAA policy to less than 10 percent of the residences in the neighborhood (as logically bounded by either streets or other geographic delineation), but by FAA policy in no case more than 20 residences total in a phase of the noise insulation program. Where there are more than 10 percent or 20 residences proposed for neighborhood equity packages, the costs of this work must be funded with other, non-federal, sources of funds. If a sponsor proposes the use of secondary packages for neighborhood equity, the sponsor must pro- vide a list to the ADO that outlines the number of residences that are proposed for noise insulation, breaking down the residences that meet criteria and those that do not. The sponsorâs report must also provide detailed information about the proposed neighborhood equity package including costs of the secondary package compared to the cost of a standard noise insulation package. The ADO must review and approve/disapprove the sponsorâs proposed neighborhood equity pack- age to ensure that the use of the minimal neighborhood equity packages on non-eligible residences is required to allow successful completion of the overall noise insulation program in the neighborhood, thus allowing these residences to be noise insulated within the guidelines of AIP eligibility. The ADO must document the approval of the noise insulation package in the project files. In extremely rare cases, the ADO may determine that the program will benefit by providing noise equity packages to more than the 10 percent/no more than 20 residence limit. In this instance, the ADO must receive APP-1 approval to exceed this limit.16 B. Assessing Level of Flexibility in Design An important start-up task is to determine the values and acoustical needs that will guide the program and formulate them into a policy and procedure manual. These values are informed by investigating policy questions such as: â¢ Will the levels of treatment vary according to the noise contour? Will all homes be offered the same palette of treatments? â¢ Is there a budget or spending cap that the program will set on a per-house basis or as a percent- age of the homeâs assessed value? â¢ Will this budget achieve the quality the program needs to satisfy affected homeowners? â¢ How much flexibility and choice will the program offer, for example, in options such as color, material, or style of windows and doors? Once the guiding values are established, the program formation process should lead toward the selection of consistent, standardized program protocols. Identify the level of design flex- ibility that is to be allowed in the program. By understanding the level of unique design issues identified in the contour area through the windshield survey, informed decisions can be made. Small programs may have room for more individualized attention to variations and customiza- tion of treatments, whereas large programs may have to limit choices in order to maintain the pace of the program and secure quality control. Chapters 2 and 10 discuss program manage- ment structures. Criteria for choosing a management structure include considering how much flexibility the program needs to serve its community and deciding at what pace homes need to be treated. C. Determining Regional Product Expectations Each region of the country has unique features to its residential construction that require consideration when designing acoustical treatments. Climatic conditions necessitate thermal, solar heat gain, and wind load performance on fenestration products that are locally defined. 16 See note 4. Attachment 1, Â§812 (d)(1),Table 4, p. 1-12.
100 Guidelines for Airport Sound Insulation Programs Styles of homes may determine materials that are appropriate and incorporate window patterns with customized shapes. If the program is in a high wind region, the window will be subjected to damaging pressure, thereby requiring a stronger frame and hardware or thicker glass. By understanding both the requirements for noise reduction and the expectations of homeowners and local codes, programs can offer sound insulation treatments that are effective and regionally appropriate. Another consideration when choosing products is whether more than one manufacturer makes the product that the program requires. If only one source is available, special procedures are in place with the FAA and other public funding agencies to approve a sole source provision, but these are time consuming and require extensive documentation and should be avoided if possible. While meeting a specific need, choosing a sole source product limits competitive bid- ding. Availability is also a factor in choosing products. Consider the ability of a manufacturer to meet the construction schedule when making promises to the community. If the program chooses a product that has limited availability, the delivery of treatment to homeowners will require adjustment. D. Program Specifications and Evaluating Products Construction professionals, architects, engineers, and general contractors use written speci- fications to communicate the quality of products to be installed in a given project. The creation of standard program specifications establishes quality levels for programs, ensures consistency between bid packages and in neighborhoods, puts research in the design phase rather than during shop drawing and submittal reviews when time is constricted, and helps project costs for bidding. To provide clarity on the quality expected, specifiers use performance standards that are promulgated by testing agencies and professional associations. Designations such as HMMA (Hollow Metal Manufacturers Association), ASTM, and AAMA refer to organizations that establish product standards. These standards provide a common language for design- ers and contractors to use in choosing the right product for a project. Products are reviewed according to their ability to meet minimum requirements such as air infiltration, water infil- tration, thermal performance, and strength under stress conditions. Additional performance characteristics are considered for products that are to reduce noise, such as STC or NR (noise reduction) ratings. Establishing a performance standard should involve an understanding of what is available to meet the standard. There are manufacturers of architectural products that serve the sound insu- lation market. This is further discussed in Chapter 9, with some current product manufacturers listed in Appendix C. While the national providers are an important element in providing quality sound insula- tion, working with local companies can be useful to a program. However, the local companies must meet standards for warranty, quality, consistency, and performance. If they are not familiar with the paperwork required for participating in a federal program, they may need to be guided through the process. One purpose of a pilot program may be to test local products or new theo- ries on installation in an unusual construction type. Also, a new assembly of materials can be field tested to determine their effectiveness. An important aspect of evaluating products for inclusion in AIP-funded projects is satisfying the federal Buy American requirements. A reference to the Buy American Act is in Chapter 11 under the section on program assurances. ACRP Legal Research Digest 18: Buy American Requirements for Federally Funded Airports was published in March 2013. It is a useful reference for sponsors and consultants who have questions regarding Buy American requirements for AIP-funded programs such as SIPs.
Design of Architectural Treatment Strategies 101 5.2.9 ACRP Project 02-31, âAssessment of Sound Insulation Treatmentsâ At the time of the publication of these guidelines, the Airport Cooperative Research Program began ACRP Project 02-31, âAssessment of Sound Insulation Treatments,â to conduct research and provide evaluation of the performance of acoustical products and treatments in previous SIPs, including the proper maintenance required to ensure the longevity of the installed acousti- cal treatments. It is recommended that users of these guidelines review the results and recom- mendations of ACRP Project 02-31 for further information regarding sustainable and effective noise reduction products and treatment strategies. 5.2.10 Best Practice Recommendations: Residential Treatments 1. Conduct a thorough inventory of the housing stock to catalog eligible buildings in the contour if that was not already done as part of the Part 150 noise compatibility study. 2. Establish typologies to help generate program policies that can be applied across multiple residences without necessarily acoustically testing each home to determine treatment goals. 3. Understand that the codes for residential and institutional buildings differ greatly, especially if working on both types of properties. 4. Pay special attention to noise paths of home additions since these additions can be built of lighter-weight construction than the rest of the home. 5. Implement construction quality-control procedures to reduce the risk of improperly installed products. The best design poorly executed will not ensure needed perfor- mance or homeowner satisfaction. On-site observation services provided by quali- fied project representatives are the best defense against deficient installations. 6. Two primary hazardous materials, asbestos and lead paint, are often encountered in homes. Work with a local hazardous materials consultant to formulate policies and procedures as an important part of program formation. 7. Allow for the consistent treatment of all windows, doors, and ventilation systems that are part of the occupiable home and subject to noise disturbance. 5.3 Public Buildings In addition to residential structures, noise generated by airport operations affects noise- sensitive structures like schools, libraries, places of worship, nursing homes, hospitals, com- munity centers, and performance spaces. Unlike residential structures, where a typology of architectural features can be determined, public buildings will be unique in design and con- struction. Therefore, while the AIP Handbook is more specific on residential structures, it understands that the treatment protocols for public buildings will require custom sound insu- lating solutions. The AIP Handbook, FAA 5100.38C, Chapter 8, Section 812.c, states: For schools, the usual design objective for classroom environment is a time-average A-weighted sound level of 45 dBA resulting from aircraft operations during normal school hours. As with residential noise insulation, a school project should reduce existing noise levels by at least 5 dBA for the same time-average school hoursâ time frame.
102 Guidelines for Airport Sound Insulation Programs General practice is that requirements for schools set the standard for treatment of other non- residential properties. Aircraft over-flights can cause disruptions to the ability to understand speech in such structures. Many noise mitigation programs adopt speech interference metrics as a guide to providing appropriate levels of sound insulation in classrooms, churches, and other noise-sensitive public spaces. The use of the term âusualâ in the FAA guidelines for schools allows room for the application of supplemental metrics as the study of the impact of noise on learning continues to evolve. The standard recommended by FICAN is to provide an interior learning environment with no greater than a 60-dBA noise level during the 95th percentile of the flights in order to eliminate speech interference.17 This is described as Lmax, or maximum level of noise. 5.3.1 Treatment Strategy To achieve a balance of cost, constructability, and acoustic performance, coordination of structural, mechanical, and acoustic design is required. Using engineering calculation models to project the performance of modifications provides the basis for the recommended sound mitigation treatment options. A. Building Envelope As with residential projects, walls and ceilings are the first elements to be reviewed for noise paths. Public buildings have larger spaces than homes, and the potential percentage impact of a lightweight ceiling/roof is great. In general, the walls of public buildings are constructed of heavier mass than wood-frame construction and rarely require direct treatment. However, the opposite is true for the ceilings. As shown in the before-and-after photos of a treated commu- nity space (Figure 5.16), the lack of a ceiling covering the exposed roof deck was the major noise path into the space. Several skylights and direct venting HVAC systems further increased the noise penetration. The windows and doors were a minor noise path into the space. Treatment of ceilings involves lighting and mechanical penetrations as well as structural reinforcement for new loads. B. Mechanical Systems Working in public buildings requires a different level of communication and discussion than residential work. Most of the noise-sensitive institutions are public or not-for-profit organiza- tions, and renovations to their buildings will occasion questions about the operational costs of any new systems in their buildings. Fortunately, the new systems are usually much more energy efficient than what will be replaced. Providing ventilation for public buildings is much more complex than for residential build- ings. Commercial building codes govern construction and renovation of schools, places of wor- ship, and community buildings. This means fresh air requirements and thermal loads are more exacting based on the occupancy of the building. Some buildings are part of a larger institutional system, and treatment decisions may need to be reviewed in the context of facility standards. For example, school systems may set standards for levels of quality or energy usage of equipment in their buildings. In one northern region elementary school, a unique program of ducted ventilation air with an innovative low-tech cool- ing option using ceiling fans was selected over an air conditioning option due to operating costs 17 Federal Interagency Committee on Noise, Federal Agency Review of Selected Airport Noise Analysis Issues, Technical Report, Volume 2, August 1992.
Design of Architectural Treatment Strategies 103 and the desire to avoid setting an unattainable precedent for schools in their district outside of the noise contour. C. Building Codes for Public Buildings There are many components to a successful nonresidential sound insulation project, but it is important to determine early in the process which governmental entities have jurisdiction over the project and what their distinctive requirements and approval processes are. It is not unheard of for state, school district, and local jurisdictions to have unique regulations and submittal requirements. Project schedules must be adjusted to allow for review at each level. In school construction, be aware that some agencies may have extensive review time, depending on their current backlog or time of year. The code analysis starts with the International Existing Building Code if the jurisdiction has adopted it. As with residential projects, it is imperative for the program to provide a code analysis of the projected scope of work to the building officials early in the design process. The discussion will need to identify what level of repair or alteration the building officials assign to the work. For mechanical system replacement, the International Mechanical and National Electrical Codes will govern the work. As with residential projects, most of the public buildings that are eligible for sound insulation were built prior to current code standards, necessitating a thorough review of the existing condi- tions. If building elements that require accessibility for people with disabilities are to be replaced as part of sound mitigation, the proposed treatments will reflect those requirements. 5.3.2 Defining Eligibility Within a Building Under FAA guidelines, all occupied school spaces are eligible for treatment except gyms, cafeterias, and hallways, unless these spaces are used for instructional activities and assem- blies. Offices in schools are eligible for treatment under this FAA guideline. Offices are sup- portive to the main educational and community purpose of the building and do not comprise the majority of the building. Programs need to evaluate the percent of the floor area not used for congregating or instructional activities and establish a policy on recommendations for treatment of those areas. Figure 5.16. Community building before and after treatment.
104 Guidelines for Airport Sound Insulation Programs When treatment recommendations do not include treating every exterior opening of a build- ing, consideration should be given to faÃ§ade consistency and reasonable design judgments for architectural continuity. Some programs have allowed schools to contribute to the construction costs of coordinating treatments for non-eligible spaces. Accounting for this cost sharing may require a memorandum of understanding with the regional FAA and full disclosure in the con- struction contract. 5.3.3 Schools A. Impact to Learning Environment Since FICANâs 1992 recommendation, the standard for classroom noise intrusion has con- tinued to evolve. The current ANSI recommendation for school design (ANSI S12.60-2002 R-2009)18 calls for a classroom environment with a noise background level of no greater than 35 dBA. This is significantly lower than the 45-dBA interior cited as usual in the AIP Handbook as amended by PGL 12-09. While the ANSI standard is not yet codified in the IBC, it is worth noting since the recom- mendations of the ANSI standard have been implemented in a number of states, including Ohio, New Hampshire, New Jersey, Minnesota, and Connecticut. Other classroom acoustics standards and directives based on ANSI S12.60 are in use in the states of California, Washington, and New York as well as in the Philadelphia, Minneapolis, and Washington, D.C., school districts. As the designated national standards entity, the ANSI recommendation will likely be the resource used in updates to the national building codes. In addition, the U.S. Access Board has proposed referencing ANSI S12.60 in the 2012 IBC. This standard may affect the sound insula- tion of schools if incorporated into the code for the renovation of existing buildings. B. Modular Classrooms Modular classrooms can be sound insulated, and several programs have done this. With many schools, a feasibility or justification study is done to test and design schematic treatments for the entire campus prior to a full commitment to treatment. During that process, additional consid- erations that are applied to treating modulars are: â¢ What is the extent of the design treatments needed to effectively sound insulate the structure? â¢ Is the structure considered a permanent part of the school facility, with a 10- to 20-year life span? â¢ What is the costâbenefit analysis, and will the treatments be cost-effective? After these due diligence items are established, consult the FAA to determine whether the school project will be funded. Unlike mobile homes, which have minimal construction and a temporary nature, modular classrooms are more permanent in construction. They are standardly built using 2x4 framing and are constructed similarly to a modular home. Modular homes that have been placed on per- manent foundations have also been treated in residential sound insulation programs across the country. The only real difference is that the modular units are partially constructed in a factory rather than stick built on site. In addition to being built on a movable chassis, mobile homes have a much different construction, making upgrading the walls and ceilings to meet noise reduction properties of standard construction cost prohibitive and space consuming. To sound insulate modular classrooms, they should be assessed as any other construction type by evaluating sound paths into the structure. If the walls and ceilings are a minimum Â½-in. 18 ANSI, ANSI S 12.60-2002 R2009, Acoustical Performance Criteria, Design Requirements, and Guidelines for Schools.
Design of Architectural Treatment Strategies 105 GWB construction on wood studs/joists with a standard exterior sheathing, those walls and ceil- ings need only be treated if the level of exterior noise exposure is too high to achieve the desired interior noise levels. The possible treatments for these structures include: â¢ New windows, â¢ New doors, â¢ New accessible entry platforms, â¢ New HVAC systems, â¢ New GWB wall layer, â¢ New acoustical ceiling-tile ceilings, and â¢ Structural reinforcement to meet seismic loads. 5.3.4 Best Practice Recommendations: Public Buildings 1. Be aware that unlike residential structures, where a typology of architectural features can be determined, public buildings will be more likely to be unique in design and construction. 2. Many noise mitigation programs, in consultation with their ADO, adopt speech interference metrics as a guide to providing appropriate levels of sound insulation in classrooms, churches, and other noise-sensitive public spaces. The standard rec- ommended by FICAN is to provide an interior learning environment with no greater than a 60-dBA noise level during the 95th percentile of the flights to eliminate speech interference.19 3. Remember that public buildings have larger spaces than houses, and the potential percentage impact of a lightweight ceiling/roof is great. 4. Working with public buildings requires a different level of communication and dis- cussion than residential work. There are many components to a successful nonresidential sound insulation project, but it is important to determine early in the process which governmental entities have jurisdiction over the project and what their distinctive requirements and approval processes are. 19 See note 4. Attachment 1, Â§812 (c)(3),Table 3, p. 1-9.