Unreinforced Masonry Buildings (URM) [Washington (State)--Seattle]
City of Seattle ArcGIS Online Full Details
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Full Details
- Title
- Unreinforced Masonry Buildings (URM) [Washington (State)--Seattle]
- Description
- How were URMs in this database identified? SDCI compiled an inventory of URM buildings from various visual and permit research surveys performed over the years. This inventory was validated by reviewing photographs of the buildings, visiting selected buildings to view the exterior construction details, and reviewing permit records and other documents, to verify each building should be included. The 2016 Report to Policy Committee on URM List Validation provides a detailed description of the data validation process. Are all of Seattle's URMs included in this database? This URM database is intended to be a comprehensive inventory of URM buildings in Seattle. There may be URM buildings that were not identified during the City's inventory process; if a building is found to contain URM load bearing walls and is not included in the inventory, it will be classified as a URM and subject to future mandatory retrofit requirements. How often is this database updated? The URM database is updated regularly. How does the City recognize URM buildings as retrofitted? A URM building owner must provide the required documentation and follow submittal procedures to demonstrate compliance with Seattle Existing Building Code section 304.5.1. This code section establishes a minimum standard for a URM to be recognized as retrofitted. Once SDCI approves this documentation, the building's status in the "Confirmed Compliant Retrofit" column will be updated to "Yes". An adjacent column, "Retrofit Method per SEBC 304.5.1", will be updated to reflect the appropriate level of completed retrofit. See page 3 for further description of columns and field values. When will URM retrofits be required? Owners can undertake a voluntary retrofit at any time. Owners must retrofit URM building parapets (any wall that continues vertically past the roofline) when they are doing other permitted construction work in the building. (Per Seattle Existing Building Code 302.9 and A113.6.) The SEBC currently requires that buildings be seismically retrofitted if owners are conducting a major renovation, occupying a vacant building, or changing the use or occupancy of the building. Future mandatory requirements: The City will not require a mandatory retrofit until financial and supportive resources have been clearly identified. The City passed Resolution 32033 in 2021 guiding the development of a Seattle mandatory URM retrofit program. The resolution recommends a variety of potential funding opportunities and financial incentives to reduce the financial burden on building owners required to seismically retrofit their URMs. Once the City has adopted a mandatory URM Retrofit Ordinance, building owners will be required to meet retrofit deadlines according to the timeline associated with their URM's "Vulnerability Classification" column in the URM database. What are the URM Vulnerability Classifications and their proposed mandatory compliance timelines? URM Vulnerability Classification Proposed Mandatory Retrofit Compliance Timelines Critical vulnerability: emergency service facilities and schools 7 years High vulnerability: buildings over three stories and located in poor soil areas (i.e. liquefaction and slide areas), and buildings with occupancies designated as public assembly. 10 years Medium vulnerability: all other buildings 13 years How is the Vulnerability Classification determined? A URM building's occupancy type, height and poor soil conditions factor into its vulnerability classification. Building Height: taller URM buildings are more susceptible to damage in an earthquake. URM buildings with more than three floors, those with values greater than three in the "Stories" column of the URM database, and located in poor soil conditions, are classified as High Vulnerability. Poor Soil Conditions: Liquefaction occurs when loose, saturated soils lose their strength due to ground shaking (usually from earthquakes). Loss of soil strength can cause sinking, fracturing, and sliding of the ground surface causing significant damage to roads and buildings. Taller URM buildings located in liquefaction prone areas, designated as "Yes" in the "Liquefaction Prone" column are classified as High Vulnerability. Data informing this column was updated in 2023 and impacted the Vulnerability Classification of a number of URMs. Learn more about Seattle's Liquefaction-Prone Areas and updates. Landslides can be caused by the shaking associated with earthquakes. Taller URM buildings located in landslide prone areas are classified as High Vulnerability in the URM database. Two columns provide information on landslide hazards "Steep Slope" and "Potential Slide Area". These columns correspond with the City's mapped Environmentally Critical Areas (ECA) code. A value in either column (for URMs with 3+ stories) contributes to a URM High Vulnerability classification. Occupancy Types: Emergency Services are facilities that would be needed in a major catastrophe. Examples of Emergency Services include police and fire stations, hospitals, and communications centers. URMs designated as "Emergency" in the "Occupancy" column of the URM database are classified as Critical Vulnerability. Schools: are defined as all public and private educational facilities from nursery school to university. Schools are represented as "Schools" in the "Occupancy" column of the URM database and are classified as Critical Vulnerability. URM buildings are a collapse hazard to occupants, with risk of injury and death; a larger number of occupants increases the number of people at risk to the collapse hazard and are thus designated as High Vulnerability in the URM Database. High occupancy URM buildings are as classified as "Public Assembly" in the "Occupancy" column. Examples include theaters, auditoriums, community centers, performance halls and churches. URM Database Column Descriptions Column Title Description Address One of the addresses of the building. Some buildings have multiple addresses, and some are addressed off of more than one street. Confirmed Retrofit Seismic retrofit work is compliant with SEBC 304.5.1. Values are "Yes" for compliant or "No" for not compliant. Compliance Method Description of retrofit method per SEBC 304.5.1. 1: Substantial Alteration per SEBC Section 304.4.2. 2: Alternate Method per SEBC Appendix Chapter 6 3a: Completed substantial alteration permitted between 09/16/1996- 04/24/2009 using 1994 or later edition of SEBC. 3b: Completed substantial alteration permitted between 04/24/2009-11/15/2024 using the 2006 or later edition of SEBC. 3c: Other, as approved by the Code Official. Year Built The year the building was built, based primarily on King County Assessor's records. Buildings listed as built in 1900 were built that year or earlier. Stories The number of building stories above grade. Occupancy Primary use of the building. Many buildings have more than one use. Occupant Load The maximum number of people in a building allowed per code. Steep Slope Landslide prone area per the Environmentally Critical Areas (ECA) codes. Liquefaction Prone Liquefaction prone area per the Environmentally Critical Areas (ECA) map. Potential Slide Area Landslide prone area per the Environmentally Critical Areas (ECA) codes. Vulnerability Classification Used to inform future compliance timelines. Classification is a factor of URM height, occupancy type, and soil conditions. See previous page for detailed description. Council District The numbered council district, 1-7, which the URM is located within. Neighborhood The neighborhood which the URM is located within. Neighborhood boundaries based on city Community Reporting Areas. Overlay District Identifies districts, such as historic and conservation districts, where district rules or guidelines will inform rehabilitation work. Landmark Status Denotes whether the URM is designated as a Seattle landmark, subject to protection by city ordinance.
- Creator
- City of Seattle ArcGIS Online
- Temporal Coverage
- Last modified 2025-03-18
- Date Issued
- 2024-12-04
- Rights
- The City of Seattle makes no representation or warranty as to its accuracy, and in particular, its accuracy as to labeling, dimensions, contours, property boundaries, or placement or location of any map feature thereof.
- Access Rights
- Public
- Format
- Shapefile
- Language
- English
- Date Added
- March 06, 2025
Resource Class
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Cite and Reference
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Citation
City of Seattle ArcGIS Online (2024). Unreinforced Masonry Buildings (URM) [Washington (State)--Seattle]. . https://data-seattlecitygis.opendata.arcgis.com/datasets/SeattleCityGIS::unreinforced-masonry-buildings-urm (dataset) -
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