PV and Green Roofs

VISION

ISSUE TWELVE | SPRING 2021

PV and Green Roof Requirements You Should Know

In November of 2019, Local Laws 92 and 94 for NYC were enacted to improve the sustainability of buildings that undergo the installation of a new roof or the replacement of an entire existing roof deck or roof assembly. These laws establish requirements for the provision of either photovoltaic array systems, green vegetative roofs, or both-depending on the contiguous roof area.

All new buildings must follow the permitting and installation requirements as mandated by the NYC Department of Buildings (DOB) for all new projects; there are no retroactive requirements for existing buildings with no roof construction. For low slope roofs (less than 2:12), requirements include 200 square feet of contiguous space for solar photovoltaics or green roofs with a minimum of 4kW of PV (or green roof) if the roof square footage doesn’t achieve 200 square feet.

This requirement drops to 4kW of PV for high slope roofs (greater than 2:12) or green roofs throughout.

Calculation and Shading Reports

A licensed professional is required to sign off on the calculations to confirm PV capacity, as well as shading reports, and to delineate efficiency of the system proposed to be installed for the scope of work designated.

Image 1: PV Roof Installation In order to show compliance with these requirements, department filing forms representing the scope of work must be submitted to the DOB with accompanying drawings. Drawings showing compliance shall include the following:

Structural Fire Resistance and Support

Documentation shall show that the building’s roofing system is built to withstand the structural impacts of the proposed photovoltaic or vegetative system, as well as any fire resistive requirements.

Sustainable Roof Zone Clearly Delineated

Of course, as with most rules, exceptions exist to the mandate on implementing sustainable roofs. They include the circumstances outlined below:

Roof Setbacks

Sustainable Roof Zones are not required in the area designated for roof setbacks per the Fire Department of New York (FDNY) requirements.

These are designated areas to allow for FDNY access in the event of an emergency and, thus, must be left clear.

Rooftop Equipment

Sustainable Roof Zones are not required in the areas where rooftop equipment is located. This includes, but is not limited to, roof-mounted

Air Handling Units (AHUs), exhaust fans, vent ductwork or piping, and any clearances required for the equipment.

Terraces and Recreational Spaces

For terraces that occupy less than 25% of the floor plate, or for areas designated as recreational space for building use, there is no requirement that they be equipped with

Sustainable Roof Zones.

Steep Slope Roofs

Pitched roofs with slopes exceeding 17% and that cannot accommodate a minimum 4kW photovoltaic system shall not be required to be equipped with Sustainable Roof

Zones.

To understand the typical process followed to achieve compliance, see page 5, Figure 1.

For further information, please contact Kohler Ronan or your trusted consultant regarding the Sustainable Roof Zone requirements, Local Laws 92 and 94, and how these mandates might affect your new construction or renovation project.

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PV and Green Roofs 1

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