Rules for building hurricane shelters and safe rooms

New Construction. Appendix U is added to read as follows: “APPENDIX U HAWAI‘I HURRICANE SHELTERING PROVISIONS FOR NEW CONSTRUCTION Section U101. Community Storm Shelters. Chapter 4 is amended by adding Section 421 to read as follows: “SECTION 421 COMMUNITY STORM SHELTERS 421.1 General. In addition to other applicable requirements in this code, community storm shelters and the following specific Occupancy Category IV buildings shall be constructed in accordance with ICC/NSSA-500: (1) Designated earthquake, hurricane or other emergency shelters. (2) Designated emergency preparedness, communication, and operation centers and other facilities required for emergency response. 421.1.1 Scope. This section applies to the construction of storm shelters constructed as separate detached buildings or constructed as safe rooms within buildings for the purpose of providing safe refuge from storms that produce high winds, such as hurricanes. Such structures shall be designated to be hurricane shelters. 421.2 Definitions. The following words and terms shall, for the purposes of this chapter and as used elsewhere in this code, have the meanings shown herein. “COMMUNITY STORM SHELTER. A building, structure, or portions(s) thereof, constructed in accordance with ICC 500-08 ICC/NSSA Standard on the Design and Construction of Storm Shelters and designated for use during a severe wind storm event such as a hurricane.” Section U102. Hawai‘i Residential Safe Room. Chapter 4 is amended by adding Section 422 to read as follows: 5A-37 SUPP. 9 (1-2021) “SECTION 422 HAWAI‘I RESIDENTIAL SAFE ROOM 422.1 Performance-based design criteria. The Residential Safe Room shall meet the minimum performance specifications of Sections 422.1.1 through 422.9, and the owner of the Residential Safe Room shall comply with Section 422.10. 422.1.1 Intent and scope. The intent of the Residential Safe Room is to temporarily provide an enhanced protection area that is either: (1) fully enclosed within a dwelling or within an accessory structure to a residence; or (2) a separate structure outside of the dwelling that meets standards pursuant to 422.1.2.1 or 422.1.2.2. All Residential Safe Rooms shall be designed and constructed to withstand the wind pressures, windborne debris impacts, and other requirements of this section. 422.1.2 Alternative standards. (1) Manufactured Safe Room Designs Subject to Approval. A manufactured safe room or safe room kit may be substituted if documentation is submitted and approved by the building official. The safe room shall be engineered, tested, and manufactured to meet or exceed the criteria of this section. (2) FEMA 320 Shelter Designs Permitted. It shall be permissible to build FEMA Shelters of up to 64 square feet of floor area with walls up to 8 feet long that are built in accordance with construction details of FEMA 320. 422.2 Site criteria. Residential Safe Rooms shall not be constructed within areas subject to stream flooding, coastal flooding or dam failure inundation within any of the following areas: (1) FEMA Special Flood Hazard Areas (SFHA) subject to rainfall runoff flooding or stream or flash flooding; (2) Coastal zones “V” or “A” identified in the Flood Insurance Rate Map (FIRM) issued by FEMA for floodplain management purposes, in which the flood hazard are tides, storm surge, waves, tsunamis, or a combination of these hazards; and (3) Areas subject to dam failure inundation as determined by the Department of Land and Natural Resources. SUPP. 9 (1-2021) 5A-38 BUILDING CODE § 5A-3-24 422.3 Maximum occupancy. The safe room is permitted to be used for a maximum occupancy based on at least 15 square feet per person with a maximum of 8 persons in a room of up to 128 square feet of floor area. 422.4 Provisions for exiting. The room shall be equipped with an inward-swinging door and an impact-protected operable window suitable for a means of alternative exiting in an emergency. 422.5 Design for dead, live, wind, rain, and impact loads. 422.5.1 Structural integrity criteria. (1) The safe room shall be built with a complete structural system and a complete load path for vertical and lateral loads caused by gravity and wind. (2) The building that the safe room is built within shall be assumed to be destroyed by the storm and shall not be taken as offering any protective shielding to the safe room enclosure. (3) The ceiling structure and wall shall be capable of supporting a superimposed debris load of the full weight of any building floors and roof above, but not less than 125 psf. (4) The safe room enclosure shall be capable of simultaneously resisting lateral and uplift wind pressures corresponding to a 160 mph 3-second peak gust, determined in accordance with ASCE Standard 7, Minimum Design Loads for Buildings and Other Structures, calculated using load and importance Factors of 1.0. The site exposure factor shall be based on exposure C. The gust factor and the directionality factor shall be taken as 0.85. Topographic wind amplification caused by mountainous terrain shall be considered in accordance with the building code. Internal pressure shall be determined in accordance with ASCE – 7. (5) The safe room shall be anchored to a foundation system capable of resisting the above loading conditions. 422.5.2 Windborne debris impact protection of building enclosure elements. The entire enclosure of the safe room, including all walls, ceilings, and openings, fixed or operable windows, and all entry doors into the safe room, shall meet or exceed Level D requirements of ASTM E 1996 (Table 422.5-1). Any wall or ceiling penetration greater than 4 square inches shall be considered an opening. 5A-39 SUPP. 9 (1-2021) Exception: Electrical outlet boxes and interior lighting switches not penetrating more than 2.5-inches into the interior wall surface and a plumbing piping or conduit not greater than 1.5-inch in diameter shall be exempted from this requirement. 422.5.3 Cyclic pressure loading of glazing and protective systems. Impact protective systems shall meet the ASTM E 1996 cyclic pressure requirement for the loading given in Table 422.5-1. TABLE 422.5-1 WINDBORNE DEBRIS PROTECTION AND CYCLIC PRESSURE CRITERIA FOR RESIDENTIAL SAFE ROOMS Enclosure Wall Ceiling, ASTM E and Floor Cyclic Air 1996 Debris Debris Missile Pressure Testing - Missile Impact Size maximum inward and Level Speed maximum outward Rating pressures 2 x 4 weighing 9.0 lb. +/- 0.25 lb., 50 ft./sec. and with min. 35 psf inward D or at least length 8 ft. 45 psf outward 34 mph +/- 4-inch 422.6 Ventilation. The room shall be naturally ventilated to allow the enclosure to have approximately one air change every 2 hours. This requirement may be satisfied by 12 square inches of venting per occupant. There shall be at least two operable vents. The vents shall be protected by a cowling or other device that shall be impact tested to comply with ASTM E 1996 Level D. Alternatively, the room shall be evaluated to determine if the openings are of sufficient area to constitute an open or partially enclosed condition as defined in ASCE 7. 422.7 Communications. The safe room shall be equipped with a phone line and telephone that does not rely on a separate electrical power outlet. Alternatively, a wireless telephone shall be permitted to rely on an Uninterruptible Power Supply (UPS) battery device. 422.8 Construction documents. Construction documents for the Residential Safe Room shall be directly prepared by a Hawai‘i licensed professional structural engineer. SUPP. 9 (1-2021) 5A-40 BUILDING CODE § 5A-3-24 422.9 Special inspection. The construction or installation of the safe room shall be verified for conformance to the drawings in accordance with Chapter 17. 422.10 Notification. The owner of the safe room shall notify the State Department of Defense and county civil defense agency of the property’s Tax Map Key or Global Positioning System coordinates.” Section U102. State and County-owned public high occupancy buildings - design criteria for enhanced hurricane protection areas. Chapter 4 is amended by adding Section 423 to read as follows: “SECTION 423 STATE AND COUNTY-OWNED HIGH OCCUPANCY BUILDINGS - DESIGN CRITERIA FOR ENHANCED HURRICANE PROTECTION AREAS 423.1 Intent. The purpose of this section is to establish minimum life safety design criteria for enhanced hurricane protection areas in high occupancy state- and county-owned buildings occupied during hurricanes of up to Saffir Simpson Category 3. 423.2 Scope. This section shall apply to state- and county-owned buildings which are of Occupancy Category III and IV defined by Table 1604.5 and of the following specific occupancies: (1) Enclosed and partially enclosed structures whose primary occupancy is public assembly with an occupant load greater than 300. (2) Health care facilities with an occupant load of 50 or more resident patients, but not having surgery or emergency treatment facilities. (3) Any other state- and county-owned enclosed or partially enclosed building with an occupant load greater than 5,000. (4) Hospitals and other health care facilities having surgery or emergency treatment facilities. Exception: Facilities located within flood zone V and flood zone A that are designated by the owner to be evacuated during hurricane warnings declared by the National Weather Service, shall not be subject to these requirements. 423.3 Site criteria. 5A-41 SUPP. 9 (1-2021) 423.3.1 Flood and tsunami zones. Comply with ASCE 24-05, Flood Resistant Design and Construction, based on provisions for Occupancy Category III. (1) Floor slab on grade shall be 1.5 foot above the Base Flood Elevation of the county’s flood hazard map, or at higher elevation as determined by a modeling methodology that predicts the maximum envelope and depth of inundation including the combined effects of storm surge and wave actions with respect to a Category 3 hurricane. (2) Locate outside of V and Coastal A flood zones unless justified by site-specific analysis or designed for vertical evacuation in accordance with a method approved by the building official. When a building within a V or Coastal A zone is approved, the bottom of the lowest structural framing member of any elevated first floor space shall be 2 feet above the Base Flood Elevation of the county’s flood hazard map, or at higher elevation as determined by a modeling methodology that predicts the maximum envelope and depth of inundation including the combined effects of storm surge and wave actions with respect to a Category 3 hurricane. (3) Locate outside of Tsunami evacuation zones unless justified by site-specific analysis or designed for vertical evacuation in accordance with a method approved by the building official. 423.3.2 Emergency vehicle access. Provide at least one route for emergency vehicle access. The portion of the emergency route within the site shall be above the 100-year flood elevation. 423.3.3 Landscaping and utility laydown impact hazards. Landscaping around the building shall be designed to provide standoff separation sufficient to maintain emergency vehicle access in the event of mature tree blowdown. Trees shall not interfere with the functioning of overhead or underground utility lines, nor cause laydown or falling impact hazard to the building envelope or utility lines. 423.3.4 Adjacent buildings. The building shall not be located within 1,000 feet of any hazardous material facilities defined by Table 1604.5. Unanchored light-framed portable structures shall be not permitted within 300 feet of the building. 423.4 Enhanced hurricane protection area program requirements. SUPP. 9 (1-2021) 5A-42 BUILDING CODE § 5A-3-24 423.4.1 Applicable net area. At least 50 percent of the net square feet of a facility shall be constructed to qualify as an enhanced hurricane protection area. The net floor area shall be determined by subtracting from the gross square feet the floor area of excluded spaces, exterior walls, columns, fixed or movable objects, equipment or other features that under probable conditions cannot be removed or stored during use as a storm shelter. 423.4.2 Excluded spaces. Spaces such as mechanical and electrical rooms, storage rooms, attic and crawl spaces, shall not be considered as net floor area permitted to be occupied during a hurricane. 423.4.3 Occupancy capacity. The occupancy capacity shall be determined by dividing the net area of the enhanced hurricane protection area by 15 square feet net floor area per person. 423.4.4 Toilets and hand washing facilities. Provide a minimum of 1 toilet per 50 enhanced hurricane protection area occupants and a minimum of 1 sink per 100 enhanced hurricane protection area occupants, as determined per Section 423.4.3, located within the perimeter of the enhanced hurricane protection area. These required toilet and hand-washing facilities are not in addition to those required for normal occupancy and shall be included in the overall facility fixture count. 423.4.5 Accessibility. Where the refuge occupancy accommodates more than 50 persons, provide an ADA-accessible route to a shelter area at each facility with a minimum of 1 wheelchair space for every 200 enhanced hurricane protection area occupants determined per Section 423.4.3. 423.5 Design wind, rain, and impact loads. 423.5.1 Structural design criteria. The building Main Wind Force Resisting System and structural components shall be designed per ASCE 7 for a 115 mph minimum peak 3-second gust design speed with a load factor of 1.6, and an Importance Factor for Occupancy Category III. Topographic and directionality factors shall be the site-specific values determined per Appendix W. Design for interior pressure based on the largest opening in any exterior facade or roof surface. 423.5.2 Windborne debris missile impact for building enclosure elements. Exterior glazing and glazed openings, louvers, roof openings and doors shall be provided with windborne debris impact resistance or protection systems conforming to ASTM E1996-05 Level D, i.e., 9 lb. 2 X 4 @ 50 fps (34 mph). 5A-43 SUPP. 9 (1-2021) 423.5.3 Cyclic pressure loading of impact resistive glazing or windborne impact protective systems. Resistance to the calculated maximum inward and outward pressure shall be designed to conform to ASTM E1996-05. 423.5.4 Windows. All unprotected window assemblies and their anchoring systems shall be designed and installed to meet the wind load and missile impact criteria of this section. 423.5.5 Window protective systems. Windows may be provided with permanent or deployable protective systems, provided the protective system is designed and installed to meet the wind load and missile impact criteria and completely covers the window assembly and anchoring system. 423.5.6 Doors. All exterior and interior doors subject to possible wind exposure and/or missile impact shall have doors, frames, anchoring devices, and vision panels designed and installed to resist the wind load and missile impact criteria or such doors, frames, anchoring devices, and vision panels shall be provided with impact protective systems designed and installed to resist the wind load and missile impact criteria of this section. 423.5.7 Exterior envelope. The building enclosure, including walls, roofs, glazed openings, louvers and doors, shall not be perforated or penetrated by windborne debris, as determined by compliance with ASTM E1996-05 Level C. 423.5.8 Parapets. Parapets shall satisfy the wind load and missile impact criteria of the exterior envelope. 423.5.9 Roofs. 423.5.9.1 Roof openings. Roof openings (e.g., HVAC fans, ducts, skylights) shall be provided with protection for the wind load and missile impact criteria of Sections 423.5.2 and 423.5.3. 423.5.9.2 High wind roof coverings. Roof coverings shall be specified and designed according to the latest ASTM Standards for high wind uplift forces. 423.5.9.3 Roof drainage. Roofs shall have adequate slope, drains and overflow drains or scuppers sized to accommodate 100-year hourly rainfall rates in accordance with Section 1611.1, but not less than 2- inches per hour for 6 continuous hours. SUPP. 9 (1-2021) 5A-44 BUILDING CODE § 5A-3-24 423.6 Ventilation. 423.6.1 Mechanical ventilation. Mechanical ventilation as required per the International Mechanical Code. Air intakes and exhausts shall be designed and installed to meet the wind load and missile impact criteria of Sections 423.5.2 and 423.5.3. 423.6.2 HVAC equipment anchorage. HVAC equipment mounted on roofs and anchoring systems shall be designed and installed to meet the wind load criteria. Roof openings for roof-mounted HVAC equipment shall have a 12-inch-high curb designed to prevent the entry of rain water. 423.7 Standby electrical system capability. Provide a standby emergency electrical power system per Chapter 27 and NFPA 70 Article 700 Emergency Systems and Article 701 Legally Required Standby Systems, which shall have the capability of being connected to an emergency generator or other temporary power source. The emergency system capabilities shall include: (1) An emergency lighting system, (2) Illuminated exit signs, (3) Fire protection system(s), alarm and sprinkler, and (4) Minimum mechanical ventilation for health/safety purposes. 423.7.1 Emergency generator. When emergency generators are pre-installed, the facility housing the generator, permanent or portable, shall be an enclosed area designed to protect the generators from wind and missile impact. Generators hardened by the manufacturer to withstand the area’s design wind and missile impact criteria shall be exempt from the enclosed area criteria requirement. 423.8 Quality assurance. 423.8.1 Information on construction documents. Construction Documents shall include design criteria, the occupancy capacity of the enhanced hurricane protective area, and Project Specifications shall include opening protection devices. Floor plans shall indicate all enhanced hurricane protection area portions of the facility and exiting routes there from. The latitude and longitude coordinates of the building shall be recorded on the construction documents. 5A-45 SUPP. 9 (1-2021) 423.8.2 Special inspection. In addition to the requirements of Chapter 17, special inspections shall include at least the following systems and components: (1) Roof cladding and roof framing connections. (2) Wall connections to roof and floor diaphragms and framing. (3) Roof and floor diaphragm systems, including collectors, drag struts and boundary elements. (4) Vertical windforce-resisting systems, including braced frames, moment frames and shear walls. (5) Windforce-resisting system connections to the foundation. (6) Fabrication and installation of systems or components required to meet the impact-resistance requirements of Section 1609.1.2. Exception: Fabrication of manufactured systems or components that have a label indicating compliance with the wind-load and impact- resistance requirements of this code. 423.8.3 Quality assurance plan. A construction quality assurance program shall be included in the Construction Documents, including: (1) The materials, systems, components and work required to have special inspection or testing by the building official or by the registered design professional responsible for each portion of the work. (2) The type and extent of each special inspection. (3) The type and extent of each test. (4) Additional requirements for special inspection or testing for seismic or wind resistance. (5) For each type of special inspection, identification as to whether it will be continuous special inspection or periodic special inspection. 423.8.4 Peer review. Construction Documents shall be independently reviewed by a Hawai‘i-licensed Structural Engineer. A written opinion report of compliance shall be submitted to State Civil Defense, the Building Official, and the owner. 423.9 Maintenance. The building shall be periodically inspected every three years and maintained by the owner to ensure structural integrity and compliance with this section. A report of inspection shall be furnished to State Civil Defense. SUPP. 9 (1-2021) 5A-46 BUILDING CODE § 5A-3-24 423.10 Compliance re-certification when altered, deteriorated, or damaged. Alterations shall be reviewed by a Hawai‘i-licensed structural engineer to determine whether any alterations would cause a violation of this section. Deterioration or damage to any component of the building shall require an evaluation by a Hawai‘i-licensed structural engineer to determine repairs necessary to maintain compliance with this section.” (2020, ord 20-61, sec 3.) 5A-3-24