31 Oct Massachusetts BBRS to Drop Windborne Debris Zone Requirement
Massachusetts Board of Building Regulations and Standards is proposing to drop current requirements for opening protection in windborne debris zones. If adopted in the 9th edition of the code, the change will take place immediately with no concurrency period with the 8th edition requirements. Here is a draft of the pending provision:
R301.2.1.2 Protection of openings. For high wind locations (typically the southeast shore of MA, the Cape and the Islands) the Residential code requires protection against windborne debris for building openings such as doors and windows. This requirement can be satisfied by using windows with impact resistant glazing or providing a special shutter system. Although recent data, research and modeling indicate slightly less wind speeds than historically predicted, the IRC 2015 has increased the geographical area requiring windborne debris protection. Further detailed investigation by staff indicates the new wind speeds in this extended windborne area are less than the wind speed that triggered windborne debris requirements in the 2009 IRC. With that consideration, and not finding any historical evidence indicating windborne debris has been the primary cause of major structural damage after much investigation, the windborne debris requirement has been eliminated. This simplifies design and construction and significantly reduces cost.
This change may reduce the cost of building in coastal zones by eliminating the mandate for more expensive window and door options or storm shutters. However, the change to the building code will not necessarily translate into changes for the Minimum Adequacy Standards of property-casualty insurance companies keen to encourage storm mitigation practices. The reality is that severe weather and the risks posed, are not going to vanish.
Larger and more frequent storms are associated with widely accepted climate change models and those of us living in coastal communities from Cape Cod to Cape Ann are no strangers to nor’easters. Windows and doors are the weakest point in the envelope of your home. Watching large glass areas bow in the wind is not a comforting experience. Further, many homeowners are not aware of the high potential for water intrusion that can also occur during these days long storms.
So while BBRS may choose to take a new fork in the road to risk reduction good reasons remain for coastal dwellers to be able to batten down the hatches. Be safe at home!
UPDATE: WIND BORNE DEBRIS DEFINITION CODE CHANGE:
In Chapter 52 DEFINITIONS add
WIND BORNE DEBRIS REGION. Areas within hurricane-prone regions within one mile of the coastal mean high water line where the basic wind speed is 110 miles per hour (177 km/h) or greater; or where the basic wind speed is equal to or greater than 120 miles per hour (193 km/h); or Hawaii. The coastal mean high water line, in the Massachusetts 110 mph wind zones, forms the outer edge of the red bands overlaid onto the satellite images found on the MA Department of Public Safety website at www.mass.gov/dps. For estimating purposes only, the inner edge of the red bands is approximately one mile inland from coastal mean high water. To determine whether a building is in a wind borne debris region, the building official shall use a survey, provided with the permit application and the building plan, which indicates the distance, in feet, from the location of the proposed building to the closest location of the coastal mean high water line as described above.