This article is reprinted with permission of The Honolulu Advertiser.
LIHU‘E, Kaua‘i – Your house probably can’t protect you from a 2-by-4 timber shot like an arrow at 100 mph.
It would pierce your siding, smash in your doors, even blast through a cinder-block wall – unless each block were filled with concrete.
The Federal Emergency Management Agency has recommended that people in areas prone to damaging winds build shelters inside their houses, so-called safe rooms that will protect the family even if the house is severely damaged. With a safe room, the 2-by-4 itself would shatter, not your wall.
Such issues are more than intellectual exercise for residents of Kaua‘i, who suffered devastating hurricane damage in 1982 and 1992. It’s no surprise that Kaua‘i is the first county in Hawai‘i to enact a law recommending safe rooms, and to provide tax breaks for installing them.
Kaua‘i County has adopted FEMA standards for safe rooms, and will give homeowners a $40,000 property value exemption for tax purposes effective January 1. That would mean a savings of $190 a year to homeowners under current real estate tax rates.
There are several options for building a safe room. FEMA recommends that it be a room in the main house that is used daily and can be converted to use as a shelter. It might be a reinforced closet or a bolt-down steel structure in the carport used for storage.
The room must not have any windows or be in a flood or storm surge zone. It must be able to handle winds of up to 250 mph, which is close to the highest unofficially measured wind speed during Hurricane Iniki in 1992. It needs to have at least 40 square feet of floor space for four people, and 10 square feet for each extra person.
Much of the nation’s research into wind-resistant structures was conducted at the Texas Tech University Wind Engineering Research Center. Some of the construction methods it suggests:
A safe room made of concrete would have 8-inch mortar-filled tile walls and a 4-inch concrete ceiling, all supported with iron reinforcing rod. A wood-framed safe room would have doubled.
2-by-4 studs, set 16 inches on center, faced on one side with 3/4-inch plywood and on the other with 12-gauge steel, and sheathed inside and out with 1/2-inch gypsum board.
A door can be bought or built from two sheets of 3/4-inch plywood glued together and covered with 11-gauge sheet steel. Since it would be heavy, Texas Tech recommends installing a regular door for daily use, and using the storm door only during emergencies.
One reason county officials are so supportive of the safe room concept is a severe shortage of storm-proof emergency shelters on the island.
FEMA has suggested designs for safe rooms in its book, FEMA P-320, Taking Shelter From the Storm: Building a Safe Room for Your Home or Small Business, available for download from the FEMA Library or for delivery by mail from the FEMA Publication Warehouse.