New York City Updates Energy Conservation Code; Now Current With State Code

New York City has updated its New York City Energy Conservation Code
(NYCECC), which now includes more stringent glazing and building insulation requirements. The updated code will be current with the 2020 Energy Conservation Construction Code of New York State, which is based on the 2018 International Energy Conservation Code and ASHRAE Standard 90.1-2016. The 2020 NYCECC became effective May 12, 2020, the same effective date as the state’s energy code.

The update aligns the code with the New York State Energy Research and Development Authority (NYSERDA) NYStretch Energy Code-2020, which was adopted by the New York City Council on March 29, 2020.
Updates include:
• Additional thermal envelope performance requirements for buildings choosing to comply with energy modeling;
• More stringent fenestration requirements for most assembly types;
• Allowance of source energy as a metric, instead of energy cost, for building owners opting to comply with energy modeling; and
• Whole building energy monitoring on commercial buildings.

Kathy Krafka Harkema, U.S. codes and regulatory affairs manager for the Fenestration and Glazing Industry Alliance, says the updated energy code provides an opportunity for the city’s building owners to achieve greater energy efficiency through proper selection, installation and maintenance of today’s more energy efficient glazing products.

“Changes incorporated from ASHRAE 90.1-2016 include more stringent requirements for fenestration, which reduced the U-factor and solar heat gain coefficient (0.36),” she says.

Changes incorporated from the feedback of the NYC Energy Code Advisory Committee also include reduced U-factors for fenestration, as well as default U-factors for spandrel panel assemblies. U-factors are now material dependent, explains Krafka Harkema. New U-factor requirements include:
• Non-metal framing: U-factor of 0.28. This was previously a U-factor of 0.38 for fixed units and 0.45 for operable units.
• Metal framing, fixed: U-factor of 0.30 (below 95 feet) and 0.36 (95 feet and above). Both previously required a U-factor of 0.38.
• Metal framing, operable: U-factor of 0.40 (below 95 feet) and 0.42 (95 feet
and above). Both previously required a U-factor of 0.45.
• Curtainwall, fixed: U-factor of 0.36 (all heights). This was previously 0.38.

“The 2020 NYC Energy Code also requires thermal bridge documentation for all new buildings, including both commercial and residential construction. The requirement also applies to all additions to residential or commercial buildings, as well as any alteration where the building envelope is part of the project scope,” says Krafka Harkema.

ASTM Highlights Windborne Debris Standard

ASTM International gave a history lesson on its windborne debris standards for glazing systems. David Hattis, president of Building Technology Inc., led the webinar titled, “Windborne Debris Standards in Hurricanes for Exterior Windows, Curtain Walls, Doors, and Impact Protective Systems.”

Hattis explained that Hurricane Alicia, which hit Houston in August 1983, was when the industry originally recognized that windborne debris is a major source of glass breakage during hurricane events.

“If debris breaks the building envelope, windows or glazed openings it causes pressurization,” said Hattis, adding that when a building is partially enclosed the interior pressure increases significantly and can lead to a partial or full building collapse.

The immediate response to the recognition of the problem was windborne debris impact research conducted by Professor Joseph Minor at Texas Tech University.

ASTM Task Group E06.51.17 was established in the early 1990s with Hattis as chair. Their goal was to develop a test method followed by a specification. The first part of the test involves impacts by missiles representing windborne debris. The second is pressure cycling, which represents hurricane winds with positive and negative pressures.

The impact test includes two types of missiles: a large missile and a small missile. The large missile is a 2×4 of timber to represent the structural elements while the small missile is a steel shot, which represents roof gravel. The missiles are shot from two types of apparatus: an air cannon and a bungee. However, Hattis said that most tests currently use the air cannon.

The glazing system is then subjected to 9,000 pressure cycles, which can take seven to eight hours.

Three specimens must be tested for the large and small missile tests and three impact locations must be chosen for each. For the large missile test the glass must be hit in the center, in one corner and then in the opposite corner. For the small missile test the glass must be hit in three different spots at one time. To pass, fenestration can have no tear formed longer than 5 inches nor any opening through which a 3-inch sphere can pass.

Hattis said one of the most important changes that’s been made to the standards is impact protective system substitutions. He explained that manufacturers wanted to be able to change out minor details without having to retest three identical specimens. Four substitution categories were created:

Automatic: No additional testing or analysis necessary;
Engineering analysis: Demonstrated or documented performance through a review of materials that predicates a minimum of equivalent performance required;
Single specimen: One specimen to be tested, identical to the original specimens qualified with the only difference being the elements to be substituted; and
Not allowed: A substitution not qualified by testing of a single specimen. Three identical specimens out of four are required to qualify the substitution, such as a new product.

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