important alert
State closes I-5 southbound at Rose Quarter for 5 weeks starting Sept. 11

Plan for major delays. More at i5rosequarter.org. Visit Shift Your Trip to keep Portland moving.

informational alert
Portland is a Sanctuary City

Building Code Guide 12-10: FRP Screening

Label: Information
Can Fiber Reinforced Plastic (FRP) be used to construct rooftop antenna screens? What are the design and construction requirements and limitations for FRP rooftop antenna screens? We answer your questions about the application of building codes and outline optional alternates.

Building Code Guides (BCGs) provide a comprehensive alternative to a complicated set of code requirements.

QUESTION: Can Fiber Reinforced Plastic (FRP) be used to construct rooftop antenna screens? What are the specific design and construction requirements and limitations that must be considered when designing and building FRP rooftop antenna screens?

RESPONSE:  Antennas and other equipment related to wireless communication services are often installed on roofs and screened from public view with fiber reinforced plastic (FRP) materials. Screens constructed of conventional building materials, wood and steel, tend to interfere with or block the signals passing from and to the antennas.

Equipment screening must be constructed of the materials specified for exterior walls in accordance with the type of construction of the building. FRP is a combustible material and is not allowed unless the screening is at least 20 feet from the property lines and a maximum 4 feet in height. Most screens are taller than 4 feet.

In order to meet the needs of the wireless communication providers, Portland Permitting & Development (PP&D) will allow the use of plastic materials (FRP) for the purpose of screening wireless rooftop antennas and other related equipment under the conditions outlined in this code guide.

Requirements and Limitations for the use of Fiber Reinforced Plastics in Rooftop Screening Applications

A. GENERAL

  1. All FRP rooftop screening plans shall be submitted for review and approval by the Building Official and Fire Marshal prior to permit issuance.
  2. Fiber Reinforced Plastic (FRP) products proposed for use within the jurisdiction of the City of Portland must have a valid evaluation report. Examples include International Code Council Evaluation Service (ICC-ES) reports, UL Evaluation Reports, or Intertek reports. The report must be current and must address structural and fire behavior properties. Reports validating the allowable use of an FRP product must be made available to PP&D. The design of the FRP screen must meet all of the requirements given in the evaluation report for the FRP product being specified.
  3. The fabrication of the FRP product must be in accordance with manufacturer's quality control manual.
  4. The engineer of record for the FRP screen design must specify the manufacturer of all FRP products that are to be used in the construction of any FRP screen structure. This information must be shown on the permit documents. All FRP products used must be labeled with the name of the product manufacturer.
  5. For cases where the requirements of this guide and a product-specific test report are in conflict, the more restrictive requirement must be met.
  6. A complete permit application will include plans and structural calculations prepared, stamped and signed by an engineer licensed in the State of Oregon.
  7. In addition to all the requirements listed in this guide, the rooftop screening must meet the height, design and other requirements of the Portland Zoning Code.

B. DESIGN AND CONSTRUCTION

  1. The FRP screen systems must not include any type of covered roof structure.
  2. The FRP screen must not exceed 18'-0" in height above the roof deck as described in OSSC 1511.6.1. The exception for Type IA does not apply.
  3. Fire separation:
    1. Rooftop screening located at least 20 feet from any interior property line must have a maximum flame spread of 25 and meet all requirements as necessary to be the equivalent of fire treated wood.
    2. Rooftop screening located at least 10 feet and less than 20 feet from any interior property line must be classified as CC1 or better in addition to the requirements in 3a.
    3. FRP rooftop screening is not permitted to be located less than 10 feet from an interior property line.
    4. Where the evaluation report does not demonstrate the product is equivalent to fire-retardant treated wood or meet the CC1 classification, the applicant must submit a technical opinion report prepared and signed by a fire protection engineer to establish equivalency for the specified FRP product.
  4. The rooftop screening must be located no closer than 5'-0" clear from any mechanical equipment. Verify whether any specific equipment requires larger clearances and provide as necessary.
  5. The rooftop screening must not obstruct fire department access to the roof. For example, rooftop screening that blocks all access on the street face of the building, or dominant face, for ground ladders or aerial access will not be approved.
  6. The rooftop screening must not block any means of egress or emergency escape and rescue for the occupants of the building.
  7. The rooftop screening must not obstruct roof drainage.
  8. Access pathways must be provided as described in this document. Access pathways must be clear of any smoke and heat vents, other roof vents, drains or other small obstructions. Access pathways must be a minimum of 5'-0" wide and have a minimum overhead clearance of 7'-0".
  9. The rooftop screening must be located such that an access pathway is maintained on three sides of the rooftop screen. The bottom edge of sloped roofs (slope > 2:12) must not be used as a pathway.
  10. Access pathways must be provided at 50'-0" maximum along each length of screen wall.
  11. Screening must not be illuminated or electrified.
  12. FRP structures must be built in the shop as much as possible. If any field cutting is required, all cut edges and drilled holes must be sealed using a vinyl ester sealing kit supplied by the manufacturer.
  13. Engineering design:
    1. Engineering design must be based on the properties and safety factors given in the evaluation report for the product specified on the design drawings. The design must provide a complete load path for all code prescribed loads on the screen structure.
    2. Moment connections are not allowed for resisting lateral or vertical loads.
    3. FRP panels may not be used as shear panels to resist lateral loads.
    4. All connections must be made with FRP or steel bolts or threaded rods and nuts. Plastic epoxy or adhesive may not be used when designing connections.
    5. In applications where extreme temperatures are expected, the design must consider the reduced capacities of FRP at elevated temperatures.

C. INSPECTION

Special inspection must be provided for FRP installations.

  1. The special inspector must verify that the FRP material specified on the approved design documents is being installed.
  2. The special inspector must verify that all cut edges and drilled holes are properly sealed using a vinyl ester sealing kit supplied by the manufacturer.
  3. The special inspector must verify that the structure is built in accordance with the approved design documents.

Alternative proposals not meeting the standards of this code guide may be approved on a case-by-case basis through the building code administrative appeals process.


HISTORY: Implemented April 9, 2012. Updated March 7, 2017,  August 17, 2022, and August 18, 2026.

DOWNLOAD a copy of this Code Guide:

QUESTIONS? Free 15-Minute Appointments for Permit, Code, and Zoning Questions

Back to top