Strict Testing Standards for Steel Windows Needed to Reduce Insurance Losses from Extreme Weather Events

Robust product testing improves life-safety and reduces property and casualty claim costs 

By Seth Rose, Founding Director, Eneref Institute

Atlantic hurricanes have become significantly more powerful in the last decade and will continue to get stronger. As storm intensities increase due to global warming so too will the damage inflicted on building structures. The growing number of property and casualty insurance claims is just one indicator of changing weather patterns.

The foundation of the Eneref Institute’s Code for Climate campaign is the immense need for more stringent window testing to meet building code requirements and to withstand extreme weather events in light of these changing weather patterns. Strengthening the building envelope of existing structures will prevent damage from climate change and offer other life-safety benefits as well.

Extreme Weather Events Driving Costly Property & Casualty Insurance Claims

Extreme weather events will continue to increase in intensity, frequency, and the areas affected by these events will likewise grow in the coming years. This will lead to increased property damage if not properly prepared. Hurricanes Harvey, Irma, Maria, and Nate caused over $250 billion in property and casualty damage in the United States. The National Oceanic and Atmospheric Administration (NOAA) found that 90 percent of fatalities are caused by water and 50 percent of those deaths were due to storm-surge. This underscores the need for greater integrity in the building envelope and code enforcement.

There are five major reasons for property and casualty events that damage custom steel windows. Field research by Eneref Institute determined that some contractors do not comply with code if not compelled to do so by a code enforcement official. Second, some code officials are unfamiliar with custom window products that are not listed and do not meet code. Third, manufacturers do not always test for design load, and fourth, architects historically focus more on energy efficiency and thermal performance. The final reason for costly property and casualty claims is that insurance companies rely on existing building envelope systems, not realizing that some custom steel windows do not meet current building codes.

Product Testing Ensures Integrity in Extreme Weather

Before entering the market, products should, of course, be tested to ensure their structural integrity. Products are tested for resistance to air, water, structural damage, thermal intrusion, impact, fire, and forced entry. According to Eneref Institute research, window manufacturers use a broad range of testing standards. One example of a company that rigorously tests windows on each area of code compliance is Hope’s^® Windows, Inc., maker of steel-framed windows and doors in Jamestown, NY. Their windows have proven to stand up to the most inclement weather because of their very high quality, which has been a direct result of extremely rigorous testing standards.

The company subjects its products to more third-party testing and certifications than any other custom steel window and door manufacturer evaluated in the Eneref Institute research. In addition, the Hope’s Windows engineers make certain their products meet and often exceed the building code requirements of any project.

A window’s integrity is tested in pressure load, and measured in pounds per square foot (psf). Tests for integrity are performed inside a vacuum chamber where manufacturers look at several factors including air infiltration, heavy rain water resistance, structural endurance and robustness. These tests are meant to determine the durability of the window’s glass, frames, and anchorage. If not strong enough, the glazing (glass) may fail or the anchorage may fail causing the entire frame to be ripped from the wall. Catching failures during a test prevents expensive property damage from occurring during a weather event.

A window’s energy efficiency is measured in W/m K – also known as the U-value – a unit that demonstrates the conduction of heat through the window. A better-insulated window yields a lower U-value. Windows with low U-values may lack structural integrity when or if thinner glass, such as triple-pane glass, is used, making them vulnerable in extreme weather events. The custom window market generally prioritizes energy efficiency and a low U-value despite the need for windows that can withstand stronger and more frequent extreme weather events.

In terms of air infiltration, standard residential windows must withstand a minimum air pressure of 1.57 pounds per square foot (psf) without any air infiltration. In architectural buildings, the higher-grade windows require a pressure load of 6.24 psf or greater. If not strong enough, windows may fail as they cannot resist high wind pressures.

Water and structural tests require even higher testing pressure loads. Water resistance of standard residential homes is tested at 15 percent of the design pressure for 15 minutes, while an architectural-grade home is tested at 20 percent. Architects and builders look for windows that not only remain intact during tests but also prevent water intrusion so as to minimize expensive repairs.

Window frames are traditionally made from wood, fiberglass, vinyl, aluminum composite, steel or bronze. Hot-rolled steel windows are the most structurally secure. In the hot-rolling process, the metal is heated to such an extreme temperature that it becomes malleable and is then shaped by passing through an array of precision tooling into its final shape. Solid steel windows are incredibly durable, making them popular for retrofit construction. Steel windows perform well in general, but it is essential that the manufacturer carry out proper testing to ensure that the most durable products go to market.

The Case for Tested Steel Windows

Code enforcement officials should look for certifications for steel windows that have been rigorously tested. Improving the building envelope with rigorously tested windows will save lives and money. According to the Federal Emergency Management Agency (FEMA), $5 is saved for every $1 spent on home improvements to protect them from winds. Hot-rolled steel is three times stronger than aluminum and sixteen times stronger than wood, making it a superior building material choice in the right application. Implementing home improvements with rigorously tested steel windows ensures a more resilient building envelope.

Many custom window manufacturers, however, are not testing their products. Research by the Eneref Institute found that 50 percent of steel window manufacturers fail to test their products to assure even minimum code compliance. Products that have not been properly tested are more likely to fail in an extreme weather event.

On the other hand, if more custom window companies followed testing procedures similar to that of Hope’s Windows, there would be a dramatic drop in weather-related damages from field failures that would have been caught in the testing lab.

The Case for Stricter Compliance 

Better codes and enforcement of such codes will speed recovery after an extreme weather event, cause less disruption to residents and businesses, ease pressure on insurance companies, and reduce disaster relief assistance.

Coming into compliance with existing codes, in many cases, will mean using strong steel windows and doors that have gone through rigorous structural testing and will not fail in the event of high wind and water pressure. Building codes are meant to be the minimum acceptable standard used to regulate design, construction, and maintenance of buildings. Going “above code” will protect the properties and human lives.

Just five states have very high building code ratings for storm resistance: Florida, Virginia, New Jersey, South Carolina, and Connecticut. Localities with loosened codes see more costly losses, as was the case in Texas in the aftermath of Hurricane Harvey.

In our recent Eneref Report, Enforcing Mandatory Robust Building Codes for Steel Windows, the Eneref Institute calls for stronger enforcement of mandatory building codes and “above-code” construction to ensure windows and doors are properly tested for extreme weather conditions. The report examines the benefit-cost ratio of code compliance enforcement and above-code construction for windows and doors, highlighting the integrity of steel windows that have undergone testing.

No matter how complex or challenging a building code, there is a solution, and window companies need to meet these engineering challenges head-on. Our research established that Hope’s has a history of developing products to overcome environmental challenges, and then testing them rigorously, which has put them far ahead of other manufacturers in this category. More companies would do well to adopt this approach to meet the ongoing challenges of today’s weather environment.

Eneref Institute’s Code for Climate campaign is a call for stronger enforcement of mandatory existing codes and above-code construction. Using strong steel windows will reduce costly policy claims for many property and casualty insurance companies.

Looking Ahead

In the face of continually intensifying extreme weather events due to global warming, it is important to more strictly enforce building codes and build above code. Using rigorously tested products in order to come into compliance or extend beyond existing code will prevent damage from climate change. The better products will also offer life-safety benefits to residents and businesses, as well as cost- saving benefits to insurance companies.