Multi-Hazard Mitigation Plan: 17. Shelters

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Chapter 17:Shelters and gable openings in all the shelter-designated areas are estimated to be capable of providing protection for an ASTM-E-1996 Level A missile. If it desired to achieve a Type A hurricane shelter, it would be necessary to retrofit the windows and gable openings in all the shelter-designated areas so that an ASTM-E-1996 level C missile protection is provided in conformity with such shelter designation. The interior doors between the kitchen and the multi-purpose dining hall would not have to be upgraded to resist an ASTM-E-1996 Level C missile. The analysis made based on the specific properties of the standing seam metal roof indicates that the roof panels over the shelter-designated areas are adequate to resist the wind uplift pressures required for an EHPA Type hurricane shelter in Building C. It would be necessary to retrofit the windows and gable openings in all the shelter-designated areas so that an ASTM-E-1996 level D missile protection is provided in conformity with an EHPA shelter designation. The MWFRS and other secondary structural components are theoretically capable resisting wind loads that correspond to an EHPA type shelter. The capacity of Building C to resist hurricane wind loads is most likely governed by the capacity of the web verticals in the trusses over the multi-purpose dining hall. It was found that these truss elements are capable of resisting wind pressures corresponding to a peak gust wind speed at the strength level of 155-mph for the partially enclosed condition. It is important to note that an enclosed condition was not evaluated or considered, since Building C is a naturally ventilated building. Therefore, prevention of interior pressurization is considered economically impractical. A summary of the retrofits recommended above,based on Shelter Type, is as follows: • All Types: Provide and enclosure to protect exterior propane storage tank from windborne debris. • All Types: Verify, and if necessary provide, adequate anchorage of mechanical ventilation units in roof above kitchen. • All Types: Provide adequate bracing for the framing of the lay-in acoustic tile and gypsum board ceilings as they constitute a falling hazard in their existing condition. • Type A Shelter: Provide impact protection for all exterior- windows and gable openings in all the shelter-designated areas (ASTM-E-1996 Level C Missile or better). • EHPA Type Shelter: Provide impact protection for all exterior windows and gable openings in all the shelter-designated areas (ASTM-E-1996 Level D Missile or better). In addition to these recommendations, it is advised that portions of two other buildings in the school—Buildings B and E—be considered as potential candidates for hurricane shelters. 17-14 Hawaii County Multi-Hazard Mitigation Plan