Photo courtesy CRL

Movable glass systems with a CW40 Performance Grade rating identify doors well-suited for challenging applications where high loads, limits on deflection, and heavy use are expected.

Other common debris culprits include mulch used around fences or decks, or vegetation that is allowed to grow up around the treated wood. These sources can quickly turn an above-ground exposure into one that presents the same challenges to wood as direct ground contact.

Providing good ventilation is also very important in the design of a treated wood structure. Decay fungi tend to thrive in dark, damp areas. This is especially important when decks are built within two feet of the ground or are elevated and include an under-deck ceiling. Again, factoring these site conditions in on the front end of the design is important to ensure the long-term life of the project.

Wood treated to (UC4B) heavy-duty standards should be used in very severe environments or for critical structural components such as foundation piling. It is crucial to always consult local building codes for additional requirements for specific structures. These requirements should be considered when the wood will be used to support a permanent structure.

Examples of UC4B applications include:

• Heavy-duty projects or functions.
• Wood that is difficult to replace or maintain.
• Treated wood that supports a permanent structure.
• Wood that has exposure to saltwater spray.
• Wood projects in extreme and tropical climates.
• Wood used for supporting a dock, pier, or marine structure; not in salt water but above it.

Bringing Strength to a Project with Doors

Doors, especially movable glass panel systems, may seem an unlikely candidate to bolster a home’s resilience. However, unlike standard sliding door systems, manufacturers today can provide sliding and bi-folding systems with a distinguishing NAFS CW Performance Class rating, making the systems well-suited for exterior applications where high loads, limits on deflection, and heavy use are expected. Compared to similar bi-folding or sliding doors in the market, these products also offer superior thermal and structural performance using thermally broken framing and 1-inch insulating glass. Here again, securing a resilient product can be achieved by knowing standards and requiring a performance specification.

The most widely recognized and relevant standard for fenestration is the North American Fenestration Standard (NAFS) which governs windows, doors, and skylights. Known as AAMA/WDMA/CSA 101/I.S.2/A440, this standard is familiar to many specifiers and includes four Performance Class categories. Classification of window and door products under the NAFS is based on independent testing that evaluates the design pressure of wind forces acting on the fenestration (measured in pounds per square foot/psf) at a stated pressure difference (measured in pascals Pa). It is helpful to think of Performance Class as a classification system that evaluates products based on a progressively greater ability to resist wind pressure, and water penetration, and for certain operable products, greater resistance to wear and abuse. For these reasons, Performance Class can be viewed as a classification that ranks products on the basis of durability.¹⁸

The criteria for tested fenestration units in each of the Performance Classes are as follows:

• R: commonly used in one- and two-family dwellings
• LC: commonly used in low-rise and mid-rise multifamily dwellings and other buildings where larger sizes and higher loading requirements are expected.
• CW: commonly used in low-rise and mid-rise buildings where larger sizes, higher loading requirements, limits on deflection, and heavy use are expected.
• AW: commonly used in high-rise and mid-rise buildings to meet increased loading requirements and limits on deflection, and in buildings where frequent and extreme use of the fenestration products is expected.

Critically for the case of large format glass doors that may face wind and environmental hazards, CW class units are now available from select manufacturers. Bi-folding and multi-slide movable glass panel systems with a CW certification have been independently tested and shown to meet the criteria to qualify for this preferred class of fenestration. This helps design professionals when selecting and specifying such products, but ultimately it means it benefits the owners and occupants of single- and multi-family housing. The ratings reflect performance features that help achieve the goal of reducing energy use while still meeting design intents. When specified correctly, these systems can enhance the building’s visual appeal, durability, and sustainability.

Meeting Unique Weather Challenges: Florida Product Approved

Protecting structures from extreme events and hazards begins with the exterior envelope. In addition to CW performance classes, the resilience offered by movable glass panel systems can go even further, including defending homes from adverse weather conditions found in Florida and other coastal regions.

Florida state law requires certain building envelope components and systems to have either a statewide or local product approval to demonstrate resistance to structural wind loads, defined by the Florida Building Codes, as a prerequisite for building permit approval. By Florida state law, building envelope components such as roofing, shutters, doors, and windows are required to have a Florida Product Approval. This approval provides evidence that the product is suitable for use in the state of Florida based on standards set in the current Florida Building Codes. The “Approved for use in the HVHZ” or High-Velocity Hurricane Zone (HVHZ) demonstrates statewide approval, as long as specific limitations of use are provided, which limit the approved product's use to rated structural loads. A Miami-Dade Notice of Acceptance (NOA) is the local product approval that demonstrates product satisfaction of the code criteria in the High-Velocity Hurricane Zone (HVHZ) as defined by the Florida Building Codes (FBC). The evaluation protocols for the NOA and HVHZ are the same.

Approved products can be found on the Building Code Information System (BCIS) at www.floridabuilding.org/pr/pr_app_srch.aspx.

Unseen Resilience: Protecting the Acoustical Environment

Although invisible, the effects of noise pollution have come under enhanced scrutiny within the past decade. Numerous studies demonstrate the significant impact of sound on people's performance, especially when it comes to mental and physical health.¹⁹ Mental stress and psychological problems are linked to noisy environments, and excessive noise can make people more irritable and nervous.²⁰ Loud noise, especially that from road or air traffic can greatly disturb people's sleep quality. Being exposed to noisy environments has also been linked to an increased risk of cardiovascular disease and metabolic disease. The result of research into human interactions with noise has resulted in noise itself being classified as an environmental pollutant.

For a home, mitigating noise plays an important role in promoting the health and productivity of those who occupy its space. Controlling how sound moves through a structure and the building’s acoustics provides protection from external noise, enhances comfort and privacy, and reduces sound transmission and vibration passing through building elements. ASTM E90, “Standard Test Method for Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and Elements,” is the test method that covers the laboratory measurement of airborne sound transmission loss of interior and exterior building partitions and elements. Testable products and assemblies under ASTM E90 include windows, doors, interior and exterior wall constructions, floor-ceiling systems, roof assemblies, curtain wall and storefront systems, skylights, office screens, and many other types of products. The ASTM E1425 standard practice specifies standard test sizes for these systems. The data obtained from this test is used to calculate sound transmission class (STC) and outdoor-indoor transmission class (OITC) ratings in accordance with ASTM E413 and ASTM E1332 respectively. Manufacturers can provide both bi-fold and sliding glass panel systems that achieve an STC rating of 33 to 37. By using advanced products, architects and designers can create designs providing calm and private spaces, while maintaining a vibrant, open aesthetic.

Quantifying Benefits of Green

Almost half of homebuyers surveyed—46%—report that a home that minimizes its impact on the environment is important to their personal wellness.²¹ Terms like “high performance,” “quality construction,” and “operating efficiency” resonate with modern buyers.²² Selecting materials that are healthy and provide efficiency speaks to an increasingly educated residential audience. They also communicate value. These attributes create distinguishing marks in a turbulent market.

Photo courtesy CRL

ENERGY STAR reports that market studies consistently demonstrate the case for energy-efficient homes, with sale and re-sale price premiums.

Saving Energy and Bolstering Performance with Movable Glass Panel Door Systems

Windows, doors, skylights, and curtain walls, both residential and commercial, have their thermal transmittance assessed via NFRC 102–Procedure for Measuring the Steady-State Thermal Transmittance of Fenestration Systems. The thermal transmittance (U-Factor) of the product is determined by placing the product in a wall between warm and cold control rooms. Temperatures of 70ºF (21ºC) and 0ºF (-18ºC) and a wind speed of 15 mph (24 kph) are maintained in the two rooms until steady-state conditions have been met for temperature on both sides and the energy input to the warm side has been measured. The heat flow through the product is measured to determine the U-Factor of the product. The U-Factor can be used to determine energy losses through the system. This test is used in conjunction with the NFRC 100 simulation methods to prove the validity of the simulation results for the product.