Solar Photovoltaic System Installations

Baltimore County has adopted the changes to the National Fire Protection Association (NFPA) Fire Code concerning Solar Photovoltaic (PV) installations. These changes address a longstanding need for firefighters’ access to smoke ventilating areas. As a result, major changes to the installation methods of Solar PV arrays are mandated in the Baltimore County Building Code.

In addition to all other Solar PV Installation Requirements, the following information is provided as guidance for planning your installation in compliance with NFPA 1:

TYPES OF BUILDINGS

  1. One and Two Family Buildings—These are buildings with a sloped roof having a pitch greater than two inches in 12 inches. This term applies to any building having this roof pitch regardless of the type of occupancy.
  2. Other than One and Two Family Buildings—These are buildings whose roof pitch is two inches in 12 inches or less. This term applies to any building having this roof pitch regardless of the type of occupancy. The Solar PV arrays associated with these structures are limited to 150 feet by 150 feet (no greater than 150 feet along either axis).

The following types of buildings are exempt from this section: 

  • Sunrooms
  • Open porches and deck roofs
  • Group U structures (2009 International Building Code including:
    • Agricultural buildings
    • Aircraft hangars (accessory to one and two family occupancy)
    • Barns
    • Carports
    • Fences higher than six feet
    • Grain silos
    • Greenhouses (accessory to a residential occupancy)
    • Livestock shelters
    • Private garages (one story)
    • Retaining walls
    • Sheds
    • Stables
    • Tanks
    • Towers

ROOF ACCESS POINT

This is the point at which the firefighters first access the roof. This point may not be above windows or doors and must be free of overhead obstructions such as tree limbs, wires, or signs above or below the access point. This point must be located at a strong point of building construction.

The access point is located at the bottom of each access pathway. See section below.

There must be a minimum six feet clear perimeter along the edge of the roof. If either axis of the building is 250 feet or less in length, a reduction to a minimum four foot clear perimeter along the edge of the roof shall be permitted.

PATHWAYS

These are the routes to the ventilating opportunities. All pathways must be kept unobstructed. All wiring crossing the pathways must be kept as short as possible, be clearly identified, and be protected in rigid metal conduit or schedule 80 PVC. All raceways must be kept as close as possible to the roof surface so as to not present a tripping hazard while still permitting water to flow underneath the raceway.

In addition to number one above, if wiring must cross the access pathway it must be kept as low on the roof as possible to avoid any conflict with ventilating opportunities and for ladder stabilization.   

Single Ridge Layouts—A three feet wide clear pathway on each ascending side of the array must be provided for each roof slope where modules are located. These pathways must extend from the roof access point to the roof ridge. Townhouses, semi-detached, or duplex structures with adjoining roofs:

  • On separate planes—Must maintain a three feet pathway from the edge of the structural roof.
  • On the same plane—Must maintain an 18 inch pathway off the property line so that a combined three feet wide access pathway is provided.

Hip and Valley Layouts—Where modules are placed on:

  • Both ascending sides of a hip or valley—A clear pathway 18 inch wide must be maintained between each array (and its associated equipment and the hip or valley. The pathway must be unobstructed from the roof access point to the roof ridge.
  • Only one side of a hip or valley and the adjoining roof surface of the hip or valley provides an unobstructed access pathway from the roof access point to the roof ridge—the solar array (and its associated equipment may be installed directly adjacent to the hip or valley.

In addition to number one above, pathways must be:

  • Capable of supporting the weight of firefighters.
  • No less than four feet wide and clear of obstructions.
  • An unobstructed straight line from the roof edge access to skylights, ventilation hatches and fire department standpipes.
  • Centerline access pathways—Shall be provided between arrays on both axes. The width of the centerline access pathway is to be determined by the ventilation method chosen, but in any case shall be no less than four feet in width.

VENTILATION OPPORTUNITIES

A clear, three-foot wide access pathway between the roof ridge and the Solar PV array shall be provided. This access pathway must be continuous and unobstructed along the entire roof ridge.

A minimum of:

  • Eight feet wide unobstructed access pathway between arrays on both axes.
  • Four feet wide unobstructed pathway and bordering on existing roof skylights and access hatches.
  • Four feet wide unobstructed pathway and bordering on four feet by eight feet "venting cutouts" spaced every 20 feet on alternating sides of the pathway between arrays on both axes.

GROUND-MOUNTED PV ARRAYS

A clear, 10-foot area around the installation shall be provided. A gravel or other non-combustible base shall be installed and maintained under and around the installation.

SIGNAGE REQUIREMENTS

All signage must be weather resistant, and otherwise suitable for the environment.

  • Main Service Disconnect must read: “Warning: Photovoltaic Power Source” and be:
    • Affixed to the panel
    • In Red and white lettering
    • In capital letters
    • Three-fourths inches in height
    • Reflective
  • Circuit Disconnect must read “Photovoltaic Disconnect” and be:
    • Adjacent to the breaker
    • Contrasting colors
    • In capital letters
    • Three-eighths inches in height
  • Obstructions in Pathways—All raceways crossing or within access pathways must be clearly marked with red reflective coloring.

This section specifies the DC system signage requirements for conduits, enclosures, cable assemblies, combiner boxes and junction boxes, which must read: “Warning: Photovoltaic Power Source” and be:

  • Located every 10 feet, at turns, above and below penetrations, on every combiner box, and on every junction box
  • Red with white lettering
  • In capital letters
  • Three-eighths inches in height
  • Reflective