WILL OUR LUCK HOLD?

IHPA is working with local business to provide free hurricane protection assessments. The United States has been lucky. The loss of lives has steadily fallen from a high of 8,000 lives lost during the hurricane that came ashore in Galveston, TX, in 1900.

While the number of lives saved have been reduced by advanced tracking and forecasting abilities, the economic losses have continued to skyrocket. As more people move to U.S. coastlines and the demand for housing and services escalate, the potential for a severe loss is greatly increased.

About 80 percent of U.S. coastal residents from Texas to Maine have not experienced a direct hit from a major hurricane since 1900. Risk management models show that there is a 1 percent annual probability that a direct economic loss of $75 billion or more could occur somewhere in the United States from the occurrence of a hurricane. In comparison Hurricane Andrew, the most expensive storm in terms of insurance dollars, cost the insurance industry $26 billion.

The highest historical reconstructed losses using current dollar values would be the Category 4 storm to hit Miami, FL, in 1926 causing $87 billion in damages and $47 billion in insured losses.

Clearly the United States has been lucky.

Rank Hurricane/Year Damage
1. Andrew 1992 / $26.5 billion
2. Hugo 1989 / $7 billion
3. Floyd 1999 / $4.5 billion
4. Fran 1996 / $3.2 billion
5. Opal 1995 / $3 billion

WINDOW, DOOR PROTECTION: LESSONS LEARNED

IHPA window committee, chaired by Tom Johnston, has met to discuss the best ways to illustrate the danger of exposed, non-impact windows and the value to be gained by protecting the openings of the home. The committee findings:

• Damage to Windows and Doors: Lessons from Hurricane Hugo, South Carolina, and Hurricane Andrew, Florida: When window and door loss occurs, interior damage from wind and rain intrusion can be substantial. Many homes were uninhabitable for long periods after the storm subsided, although the main structural system was intact and damage appeared minimal from the outside. Windows, especially sliding glass doors, were very susceptible to failure from wind pressure and debris impact. Frame systems were
usually found intact, but only because the glazing had already failed.

The breaching of the building envelope by failure of openings (doors, windows) due to debris impact was a significant factor in much of the damage from Hurricane Andrew. After-the-storm studies have shown that roof damage from flying debris was a major problem during Andrew because of the quantity of missiles in the air stream. Missiles included tree limbs, fences, dislodged rooftop HVAC equipment and components from failed buildings.

Window protection such as shutters and impact glass performed well. Structures with adequate roof ventilation were observed to have performed better due to the ability of the ventilation to relieve induced internal pressure.

Garage door failure was a significant cause of damage during Andrew. The most common failure was deflection of the garage door from wind pressure until the tracks rotated and the door rollers separated from the tracks. Loss of doors resulted in envelope breach and a sudden increase in internal pressure.

Many researchers regard the loss of doors (primarily garage and sliding glass) and windows to be the second most costly and important cost aspect of the storm after roof damage. Many times loss of windows and doors predicated the roof loss. One investigator noted that during Hugo many anchored roofs failed because of loss of windows and sliding glass doors.

• Doors and Windows: Modern homes are constructed with more and larger openings than older homes. Entry doors are often double, sliding glass doors replace regular doors, and attached garages often have double-width garage doors to hold two cars. (Single-car garages withstand internal pressure better than multi-car garages.) The greater number and size of openings place homes at increased risk from hurricane forces.

Nearly every residential house or apartment in south Florida has at least one sliding glass door and frequently more, sometimes placed in adjacent walls. Sliding glass doors are at least six feet wide. Typical single-family homes have attached garages many with double wide garage doors.

Failure of windows and doors exposes the entire structure to increased force and loads. One research project, performed in 1994, estimated that an opening of only five percent in the windward side of a building will allow full pressurization of the interior, exerting uplift pressure on the roof and horizontal pressure against the interior walls. Clearly, the information needs to be made available to the general public.

The Federal Emergency Management Agency (FEMA) specifically states on its Web site that the openings of windows should be protected:

“High winds and windblown debris can easily break unprotected windows and then enter your house. Once inside, wind and debris can cause more damage. Protecting windows not only helps you avoid damage to your house, it also reduces the likelihood that you or members of your family will be hurt by broken glass and debris.”

IHPA continues to have discussions with various levels of government organizations on the best way to educate the consumer.