Originally published in Interiors & Sources

03/22/2005

Taking Stock of Florida’s Codes After the 2004 Hurricane Season

TechTalk

 

Photo Compliments of Solutia

A major controversy surrounds Florida’s current building codes, which allow buildings outside Miami-Dade and Broward counties to be built to “internal pressure” standards. When windows and doors are broken open by winds, pressure differences between the inside and outside of a building can dislodge the roof, after which walls generally collapse.

The devastating hurricanes of 2004 are now spinning off scattered political storms over revisions to Florida’s state and local building codes – particularly over questions about  roofing materials, internal pressure criteria and water penetration of siding, doors and windows.

“Three of the four hurricanes last year were among the most damaging to hit Florida in more than a decade,” says Nanette Lockwood, an engineer with Tampa-based Solutia Inc. and a longtime advocate for more stringent building codes in the heart of America’s “Hurricane Alley.”

Solutia manufactures a polyvinyl butyral window interlayer called KeepSafe Maximum, which, when placed between two layers of glass, significantly improves a window’s overall strength.

But Lockwood’s push for code improvements long predates her position with Solutia, and what she witnessed last year only reinforced her convictions.

“Winds demolished hundreds of homes and businesses,” she says. If certain state and local codes had been stronger, she insists, much of that destruction could have been avoided.

Back in 1992, Hurricane Andrew first revealed the extent to which Florida lacked uniformity in codes and enforcement. The  state’s answer was the 2001 Florida Building Code (FBC), adopted on March 1, 2002. It was basically an amalgam of the South Florida Building Code and some 400 local codes from around the state, but it also drew elements from the 1997 Standard Building Code, developed by what is now the International Code Council, the association of architects, engineers and government officials that develops residential and commercial building codes. The FBC used the 1998 version of ASCE 7 as its structural standard.

But the resulting FBC was actually two codes – one for the High Velocity Hurricane Zone (HVHZ), consisting of Miami-Dade and Broward counties, and a second, less stringent code for the rest of Florida.

Miami-Dade and Broward counties opted to enforce more stringent standards, Lockwood said, because they had experienced a direct hit from Andrew.

Of course, the Florida Building Code was finalized long before the 2004 storms wreaked their destruction. Now, advocates and officials alike are suggesting that the code be revisited in light of what was learned last year.

Fixing What’s Broken

The Florida Building Commission, based in Tallahassee, amends the code every three years after extensive public input. Its executive director, Rick Dixon, says, “Preliminary investigations indicate buildings built to the 2001 Florida Building Code generally performed well structurally.”

Even so, Dixon says, portions of the code are being considered for possible amendment. These include failures related to soffit installation, roof tiles, screened pool enclosures, exterior insulation and finish systems, and siding – vinyl as well as masonry – that allowed wall leakage.

Among the factors that must be considered in the wake of the 2004 season was that Hurricane Ivan created storm surges and wave action that caused damage above the building elevation requirements of the Flood Insurance Rate Maps program. In addition, Ivan’s winds caused some cladding failure that resulted in water intrusion.

Dr. Timothy Reinhold, a wind engineer and vice president of engineering for the Tampa-based Institute for Business & Home Safety, surveyed damage after each of 2004’s four storms. He says that whatever it’s shortcomings, the 2001 FBC made a difference: “When new codes were followed, we observed significant improvement in structural performance, particularly less loss of roof sheathing and structural damage.”

However, Reinhold adds: “We’re still finding major problems with some types of roof covering, depending on installation, as well as with soffits. The building code needs to better address specifications regarding water-penetration issues and details, including the pressure threshold for water penetration through windows and doors.”

Lockwood agrees with that assessment, adding, “In the midst of high-wind storms, structural openings such as failed doors and windows compromise a home’s structure.”

Beyond that, however, Lockwood, is also concerned about the code’s lack of uniformity. She worries, for example, that while Miami-Dade and Broward counties had more stringent requirements to protect windows and garage doors, much of the remainder of Florida’s cities and counties were not equally protected in the 2004 storms.

Pressures From Within and Without

In general, Lockwood says, the FBC is less stringent than both the 2003 Standard Building Code and the International Residential Code with regard to protecting doors and windows from hurricanes. This is largely because a 2002 state statute prevents the enforcement of window and door protections in the Panhandle area of the state for any building more than one mile from the water.

Even more controversial, the statute also allows buildings outside of Miami-Dade and Broward counties to be built “for internal pressures.”

The “internal pressures” criterion was largely a nod to contractors who wanted to keep building costs down, but Lockwood and others want to see the statute changed.

Jerry Sparks, AIA, CBO, CFM, who serves as building services director and designated building official for the city of St. Pete Beach in Pinellas County, is among those who criticize the “design-for-internal-pressures” option.

“Structures in wind-borne debris regions should be designed as ‘enclosed’ structures, with openings protected with impact-resistant glazing and/or hurricane storm shutters,” Sparks says. But he also concedes that perhaps this should apply only to residential structures.

“I don’t see a problem designing a commercial facility as ‘partially enclosed’,” Sparks says, “because it’s not someone’s home where, by design, the windows will blow out and all their personal possessions will be destroyed.”

Jonathan Parks, AIA, an architect from Sarasota, agrees that ridding the FBC of the “internal pressures” option should be a priority when the codes are next revised. At first blush, he admits, “designing for internal pressures seems like a good idea; after all, it keeps building costs lower.” But, he asks, “If the building is breached and still stands, but everything inside is lost, what is left? Especially, what is left for the homeowners?”

Herminio Gonzalez, director of the Miami-Dade Building Code Compliance Office, concurs that the FBC needs strengthening. “If the rest of the counties were to adopt the HVHZ provisions of the code, they would be better protected,” he says. However, he also admits that the public hearing process might make changes to the “internal pressures” criterion difficult. “Sometimes stricter codes mean more cost to the homebuilders, and they do attend the regular meetings of the commission,” he says.

Lockwood stresses that in the HVHZ, designing to internal pressures is not allowed, and in the 2004 Supplement to the International Residential Code, the option to design to internal pressures has been removed. She notes, too, that ASCE 7 2005, which will be incorporated into the 2006 IBC, will no longer allow design for internal pressures, except in the cases of agricultural, temporary and minor storage facilities. (Sparks says, in fact, that this option was eliminated from that IBC to a great extent because of Lockwood’s efforts in her previous position as director of building codes and engineering at IBHS.)

“We need to require protection for all openings – not just glazed,” Lockwood says.

But there is a catch. Even if the code were to add HVHZ-level protections throughout Florida, it would probably have very little impact for the next several hurricane seasons, since building codes affect only new construction and extensive renovations. At the current rate of construction, most existing buildings would be vulnerable to hurricanes for another 50 years.

For that reason Lockwood argues that it might be necessary to require retrofitting existing structures: “Accelerated retrofit guidelines exist for the HVHZ,” she points out. “Why not incorporate this for the rest of the state?”

Keeping the Doors Open for Disaster?

She bolsters that argument by pointing to research by Raleigh, N.C.-based Applied Research Associates (APA) suggesting that a lack of opening protection in structures built to “internal pressures” criteria can account for up to 50% of insured losses. In addition, ARA research also shows that damage from wind-borne debris begins when winds reach 105 miles per hour. Yet window and door protection is not required unless structures are built in areas that experience winds exceeding 120 mph inland or 110 mph within a mile of the coast.

Of course, when compromised, windows or doors allow pressurized outside air to find low-pressure pockets inside a building and expand. The resulting force is often enough to dislodge a roof and destroy the building. Parks points out that under current codes, this leaves garage doors vulnerable in new structures throughout the state.

Lockwood points to another inconsistency in the code: Plywood or oriented strand board by themselves do not pass any of the tests that impact-resistant windows and shutters must pass. They therefore are not options in the HVHZ. However, they are allowed throughout the rest of the state.

Sparks adds that designing to internal pressures creates compliance questions, too.

“Almost every day I review construction plans for one- or two-family dwellings in which the architect or engineer has certified that the proposed construction has been designed for the increased internal pressures of a partially enclosed structure,” he says. “However, when asked to demonstrate compliance, they are unable to, because the structural calculations have not been performed.”

Lockwood predicts that Florida homes and businesses will face even more severe challenges in the years ahead.

“Out of the four hurricanes that struck Florida last year,” she says, “only Charley was strong enough to truly test structures built under the new Florida Building Code for wind resistance.” Some future storms, she reasons, are likely to be even stronger.

Currently, the Florida Building Commission is reviewing public input – including the views of the Florida Home Builders Association – concerning FBC revisions.

Lockwood says she is concerned that the only proposed FBC changes she has heard about so far relate to water damage, which in her mind is not the major threat in hurricanes. In addition to code changes, she is pushing hard for a repeal of the 2002 “Panhandle statute.” The Florida Legislature is scheduled to consider such a repeal this session.

As for Sparks, his biggest worry is that, given the political muscle of Florida’s developers and builders, the commission “hasn’t let the fox guard the hen house.”

 


Visit our website today to learn about the design flexibility of a Morton building and the endless possibilities of partnering with our designBUILD team.


Wood construction is both cost and energy efficient. Check out Morton Buildings and our designBUILD team online today to discover all the benefits of post-frame construction.


When choosing a metal-clad building for your next construction project, consider Morton Buildings, Inc., and their designBUILD team, we’ll make your dream a reality.

Bluebeam® Revu® simplifies digital facilities document management from design review to leveraging as-builts, maintenance manuals and O&Ms submittals.

Yaskawa drives offer quality performance for air handlers and cooling towers on the roof to secondary chilled water pumps in the basement

We Can Help You Reduce Energy by 30%

Our mission is to help our customers manage their buildings' energy costs, improve reliability, and enhance performance while having a positive impact on the environment.
CLICK HERE to find out how.


Visit our website today to learn about the design flexibility of a Morton building and the endless possibilities of partnering with our designBUILD team.


Wood construction is both cost and energy efficient. Check out Morton Buildings and our designBUILD team online today to discover all the benefits of post-frame construction.


When choosing a metal-clad building for your next construction project, consider Morton Buildings, Inc., and their designBUILD team, we’ll make your dream a reality.

Bluebeam® Revu® simplifies digital facilities document management from design review to leveraging as-builts, maintenance manuals and O&Ms submittals.

Yaskawa drives offer quality performance for air handlers and cooling towers on the roof to secondary chilled water pumps in the basement

We Can Help You Reduce Energy by 30%

Our mission is to help our customers manage their buildings' energy costs, improve reliability, and enhance performance while having a positive impact on the environment.
CLICK HERE to find out how.


 
comments powered by Disqus

Sponsored Links