BLD2023-1649_Structural_Calculations_12.27.2023_1.57.51_PM_3972419Code Change Alert:
Permitting of Solar Photovoltaic Systems in Washington State
Background
Historically, the permitting requirements for rooftop solar photovoltaic (PV) systems in
Washington State have varied widely from jurisdiction to jurisdiction. Requirements for full
engineering reports and stamped drawings for simple systems has resulted in an additional
$500 to $2,500 per system for engineering -related expenses, construction delays of up to 8
weeks, and a deterrent to solar installations in some jurisdictions. In an effort to reduce
unnecessary permitting costs and to support the growing solar industry in Washington, the
Northwest Solar Communities, a coalition of industry stakeholders, jurisdictions, non -profits,
and state entities, developed an expedited process for standard rooftop mounted, residential
PV systems. The objective was to establish a permit process that is simple, fast, and cost
effective for both reviewing jurisdictions and permit applicants, and several jurisdictions across
the state have taken steps to implement streamlined processes. In order to implement a
standard, predictable process statewide, the Washington State University Energy Program
worked with the Northwest Solar Communities team to develop and submit an amendment to
the International Residential Code for solar photovoltaic systems. The amended code was
approved as an emergency rule as described below.
Emergency Rule Regarding Rooftop Solar Photovoltaic Installations
On June 13, 2014 the Washington State Building Code Council approved an emergency rule -
making order to allow installation of standard solar photovoltaic systems on residential
rooftops without the need for an engineering report. The effective date of the emergency rule
is July 1, 2014. Under the rule, the following section is added to the Washington amendments
to the International Residential Code:
WAC 51-51-2300 Section M2302—Photovoltaic solar energy systems.
M2302.2 Requirements. The installation, inspection, maintenance, repair and replacement
of photovoltaic systems and all system components shall comply with the manufacturer's
instructions, sections M2302.2.1 through M2302.2.3, NFPA 70, and the IFC as amended by
Washington State.
M2302.2.1 Roof -mounted panels and modules. Where photovoltaic panels and modules are
installed on roofs, the roof shall be constructed to support the loads imposed by such
modules.
EXCEPTION: The roof structure shall be deemed adequate to support the load of the
rooftop solar photovoltaic system if all of the following requirements are met:
1. The solar photovoltaic panel system shall be designed for the wind speed of
the local area, and shall be installed per the manufacturer's specifications.
2. The ground snow load does not exceed 70 pounds per square foot.
3. The total dead load of modules, supports, mountings, raceways, and all
other appurtenances weigh no more than four pounds per square foot.
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Code Change Alert:
Permitting of Solar Photovoltaic Systems in Washington State
4. Photovoltaic modules are not mounted higher than 18 inches above the
surface of the roofing to which they are affixed.
5. Supports for solar modules are to be installed to spread the dead load across
as many roof -framing members as needed, so that no point load exceeds 50
pounds.
Roof -mounted photovoltaic panels and modules that serve as roof covering shall conform to
the requirements for roof coverings in Chapter 9. Where mounted on or above the roof
coverings, the photovoltaic panels and modules and supporting structure shall be
constructed of noncombustible materials or fire -retardant treated wood equivalent to that
required for the roof construction.
Recommended Building Permit Process — Over the Counter
To support implementation of the emergency rule, a checklist template is available for adoption
by jurisdictions having authority throughout the state. This checklist is provided as an example
process that complies with the new code change requirements and is not required for
jurisdictions to adopt. The checklist identifies the minimal structural characteristics that the
proposed solar photovoltaic system must satisfy in order to be deemed to comply with
engineering requirements. If all of the checklist criteria are met and a site plan is provided, the
building permit can be issued over-the-counter (on-line or in person) without providing an
engineer's stamped drawing, and the inspector in the field can easily verify the system design.
As an alternative to the over-the-counter process, jurisdictions may opt to exempt solar
photovoltaic systems that satisfy the checklist criteria from building permit requirements. For
example, the City of Bellevue passed an ordinance amending the Bellevue City Code to
eliminate the permit requirement for standard rooftop solar PV installations. See:
http://www.bellevuewa.gov/Ordinances/Ord-6113.pdf and
http://www.ci.bellevue.wa.us/solar photovoltaic systems permitting.htm
Recommended Building Permit Fees
Jurisdictions should establish fees that are reasonably necessary to cover the costs of
administering and enforcing the provision of this rule. In order to obtain statewide consistency,
the following methods are provided as a suggestion in developing the cost structure for a local
jurisdiction.
1. Fixed fee. For systems that qualify for the over-the-counter building permit process, it is
recommended that a flat fee be charged for the permit. The amount of the fee should
be calculated so that it is sufficient to cover the cost of checklist review and a single
inspection. For example, the City of Edmonds has implemented a flat fee of $135 for
over-the-counter residential solar installations. (http://edmondswa.gov/additional-
links/rooftop-solar-installations.html)
2. Valuation based fee. For systems that do not qualify for the over-the-counter building
permit process, it is recommended that a valuation -based fee be charged for the permit.
Costs for building permits are often based on the total project cost, assuming that the
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Code Change Alert:
Permitting of Solar Photovoltaic Systems in Washington State
cost of the project accurately represents the scale of the project and the level of permit
review required. However, with a rooftop solar photovoltaic installation, the equipment
costs are much higher than with conventional projects of similar scope. It is therefore
recommended that the permit fee for a rooftop solar photovoltaic system be calculated
based on a valuation of the structural components and labor only. The value of the
electrical components, including the solar modules and inverters, is subtracted from the
overall valuation because these elements are not looked at as part of the structural
inspection.
Recommended Electrical Permit Process
In addition to building permit requirements, solar photovoltaic systems will require some level
of electrical permitting in order to be installed. For jurisdictions that use their own electrical
reviewers and inspectors, a checklist is available to use in determining when a solar
photovoltaic system qualifies for an over-the-counter electrical permit. The over-the-counter
checklist includes a set of electrical one -line diagram templates and is intended to simplify the
application process and minimize the need for detailed plan review. If all of the checklist
criteria are met and one -line diagrams are provided, the electrical permit can be issued over-
the-counter (on-line or in person) and the inspector in the field can easily verify the system
design. The checklist and templates are provided as an example process and are not required
for jurisdictions to adopt. The Department of Labor and Industries will also accept the electrical
diagram templates for their review and the over-the-counter process created here does not
change their authority.
For more information
To obtain electronic versions of the templates that can be modified for jurisdiction use or for
questions related to the code change, contact:
Gary Nordeen, Senior Building Science Specialist
WSU Energy Program
(360) 956-2040
nordeeng@energy.wsu.edu
www.ener2v.wsu.edu/code
Northwest Solar Communities
http://nwsolarcommunities.org/priorities/permitting/
info@nwseed.org
(206) 328-2441
WASHINGTON STATE UNIVERSITY
EXTENSION ENERGY PROGRAM
Northwest Solar
Communities
nwsolarcommunities.org July 2014