Appeal 16894

OSSC 3111.4.8.1, exceptions

OSSC 3111.4.8.1, exceptions – based upon the Oregon Solar Installation Specialty Code
The following is from:
2010 OREGON SOLAR INSTALLATION SPECIALY CODE (OSISC)
Commentary Updated October 10, 2011
304.9.1 General Pathway Requirements. All PV installations shall include a 36 inch wide (914mm) pathway maintained along three sides of the solar roof. The bottom edge of a roof with a slope that exceeds 2:12 shall not be used as a pathway. All pathways shall be located over a structurally supported area and measured from edge of the roof and horizontal ridge to the solar array or any portion thereof.
Exception:

1. On structures with a PV array area of 1,000 square feet (92.90 m2) or less installed on a roof with a slope that exceeds 2:12 and with an intersecting adjacent roof and where no section is larger than 150 feet (45720 mm) measured in length or width:

1.1. Where the PV array does not exceed 25% as measured in plan view of total roof area of the structure, a minimum 12 inch (305mm) unobstructed pathway, shall be maintained along each side of any horizontal ridge.
1.2. Where the solar array area exceeds 25% as measured in plan view of total roof area of the structure, a minimum of one 36 inch (914 mm) unobstructed pathway from ridge to eave, over a structurally supported area, must be provided in addition to a minimum 12 inch (305 mm) unobstructed pathway along each side of any horizontal ridge.

1. Pathways are not required on non-occupied accessory structures provided they are separated from occupied structures by a 6 feet (3048 mm) minimum separation distance or by a minimum two-hour fire rated assembly.
2. Townhouses providing fire separation as required by the applicable code at the time of construction may be considered one structure and comply with the provisions of Section 304.9.1(1.1).

Where townhouses are separated by real property lines and pathways cross real property lines, the building official shall review, approve and maintain a record of all easements for access related to the PV system installation. Easements may be general in nature or they may describe specific locations. The applicant shall provide a copy of the recorded easement to the building official prior to issuance of the building permit. Easements shall be recorded for each affected dwelling unit and the book and page number provided to the jurisdiction having authority.
Commentary: This section is meant to address issues that can arise in the event of a fire emergency. The committee worked with a group of solar installers, jurisdictions and fire services personnel to develop provisions that would allow for the maximum amount of space for installing solar panels, while ensuring that fire fighters can respond to a fire emergency in a safe manner. Firefighters require minimum access pathways to move about the roof during a fire event, providing an unobstructed path should the need arise to move quickly. This section contains a general requirement as well as exceptions to the general requirement for smaller systems, non-habitable accessory structures, and townhouses.
The general requirements for a 3 foot pathway on three sides of the array apply, unless one of the exceptions is met. The “solar roof” is the roof or roof plane that will have the solar panels installed on it. The bottom edge of a sloped roof cannot be used as a pathway; discussion with the fire services indicated that walking along the bottom edge of a sloped roof for venting or egress would not be safe. On a flat roof, the three 3-foot pathways can be placed wherever is convenient.
The first exception addresses solar arrays that are 1,000 square feet or less and installed on a roof with a minimum slope of 2:12. In this instance, where the array takes up less than 25% of the total roof area, and there is an adjacent roof plane(often the North facing roof) there is no requirement for a three-foot pathway; however, installers must maintain 12 inches along the ridgeline to allow for fire ladder hooks in the event of a fire. In most all instances, where a solar array comprised less than 25% of a roof’s surface there is a way for fire services personnel to get off a solared roof without having to navigate through or over panels. Gabled roofs will have an adjacent roof plan so long as one side of the roof is clear of panels.
Where a solar array is 1,000 square feet or less and takes up more than 25% of the total roof area where the slope is 2:12 or greater and there is an adjacent roof without panels, then a solar installation must allow for 12 inches at the ridge and a 3-foot pathway for fire fighter egress. Pathways on or near the eaves must be over a structurally supported area; some overhangs on older structures are cantilevered and may not support the weight of a firefighter.
Where a particular structure makes it impracticable or unlikely that the fire services will require the top ridge for ladder attachment, or impractical for fire services to walk along or vent the roof, then the building official should consider working with installers on modifications to this section. Under section 103.10 the building official has the ability to modify provisions of the code where strict adherence is impracticable.
Any required pathway must be shown on the plans.
Non-habitable accessory structures are not subject to the pathway requirements. Committee discussion was that fire services personnel will rarely need to go onto the roof of a non-habitable structure.

Although I could not find the reference, I was told that “the OSISC was integrated into the OSSC. The appropriate code reference is 3111.4.8.1, exception 2. The code language appears to be the same as quoted in the checksheet response. One of two conditions are required for the awning to not require pathways: 1) 6’ separation between the two structures, or 2) 2-hour minimum fire rated assembly. Neither of these conditions are met with this project.”

The awning to be built of steel posts and a standing seam metal roof construction and is fully detached from the house. There is a separation of 6 feet above the existing roof, in the small (less than 3’) overlap it makes above the existing roof.

The entire set of plans for this structure was approved on October 25, 2017 by the City of Portland Bureau of Development Services, as Application #17-261-229-RS. It was designed to maximize the solar output of the structure for the client. LightSource Energy was brought in to replace the former solar contractor, and our solar array design enabled the client to have even more solar production on the structure. We submitted the new design. Although the added weight of the additional panels was well within the capacity of the awning to carry (supported by a letter from the design engineer) we were told that we needed to submit an entirely new permit. It was in this new permit process that delays and complications arose that never occurred before. We obliged the request for 4’ distances called for from property lines, causing us to take 2’ off the total width of the structure. However, the setbacks of 3’ from both the top edge and sides of the structure asked for in this new permit, were not insisted upon in the original plans and should not be insisted upon here.
There is a separation of 6 feet above the existing roof, in the small (less than 3’) overlap it makes above the existing roof. The steel posts closer to the side of the house are made of non-flammable steel. The awning is a non-habitable structure.
The client is seeking the maximum solar available for the structure; the delays in approval have caused a hardship for her (she missed the expected deadline in receiving her Oregon State tax credits because of this). Our company assumed full responsibility for this project, instead of just the solar array, and promised the client that her total cost would be the same as if she had the state tax credit. Hence, we are willingly taking a loss on the project; our intent is that she gets the solar awning she was promised at the original contract price.
The salient point is that this solar awning is a free-standing, steel, uninhabitable structure, separated from the house. The comments in the Oregon Solar Installation Specialty Code address the intent and rationale behind such structures. I repeat the section with those comments below:
Non-habitable accessory structures are not subject to the pathway requirements. Committee discussion was that fire services personnel will rarely need to go onto the roof of a non-habitable structure.