To tape or not to tape windows during typhoons

Ahead of major and potentially harmful tropical storms, it is common in Macau to see people duct-taping the windows of their homes or businesses with large “X”s.

The prevailing wisdom in China is that the tape may hold the glass in larger pieces if windows break under extreme winds. However, some engineering experts and storm advisory bodies advise against the practice, saying it could make it more dangerous for those taking refuge inside.

This old habit has been called into question again recently, with many specialists warning that this particular form of preparation might just do more harm than good.

The idea is that taping windows fortifies them against the wind and prevents them from shattering into tiny pieces. In reality, it has been argued that taping does nothing to strengthen windows.

While studies have found that it does prevent windows from shattering into tiny shards of glass sent spiralling about in the wind – which might at first glance seem to be a positive conclusion – many believe that it produces something worse: larger shards held together with tape.

A 2011 survey conducted during the buildup to Hurricane Irene in the United States found that 7 in 10 respondents taped their windows in preparation for a hurricane.

The misconception has become so pervasive that it has led to the Federal Alliance for Safe Homes to initiate a campaign titled “Go Tapeless” to warn people about the ineffectiveness and danger of window taping. Instead, the organization recommends the installation of impact-resistant windows or shutters, or even plywood.

The U.S. National Hurricane Center, which is responsible for tracking and predicting weather systems within the tropics, states clearly that taping windows can be very dangerous.

Opinions in China diverge from those abroad. The authorities here, directly or indirectly, do recommend that people tape their windows during a typhoon.

As an example, the Hong Kong Observatory hosts a video on its website showing Professor Lo KK, formerly of the Department of Mechanical Engineering of Hong Kong Polytechnic University, sharing precautions and measures to undertake when facing the threat of a tropical cyclone.

“Taped glass windows are not that easy to break. Even if the window broke, [the glass] will not fly everywhere because it was taped. When we put the tape on the glass window, it is the best to put the tape in an ‘X-shape’ [due to two main reasons]. First, it saves tape; second, it is rather light-transmitting. It is a measure rather suitable for Hong Kong’s environment,” Lo says.

Mainland authorities promote a similar rule. According to a Weibo post by the China Meteorological Administration, “the middle part of the glass is relatively fragile, so putting tape on the glass window can increase the toughness of the glass and reduce the frequency of the glass vibration.”
“By doing so, the window can not only resist the rather large wind pressure, but also prevent the glass from rupturing when the window breaks,” it adds.
The same department also suggests that it is best to use sealing tape crossed on the inside of the window and “preferably attached to the outside of the window frame to give the glass center a better support point.”

In Macau, some civil engineers criticized after last year’s typhoon Hato that it was not the windows that were the problem, but rather the weak window frames in newer buildings, which are not able to withstand very powerful wind gusts.

Macau’s Meteorological and Geophysical Bureau (SMG) does not issue any kind of advice on whether residents should tape their windows in preparation for a typhoon, informing the Times yesterday that the decision falls to civil protection authorities.

According to a pamphlet released by the Unitary Police Services in June this year as part of the public consultation documents for the new “Civil Protection Basic Law,” residents are advised only to “close the doors and windows” in the event of a typhoon. The official guidance does not explicitly answer the question of whether tape should be applied, but an illustration in the pamphlet right under the guidance shows windows plastered with large crosses that are clearly meant to be tape.

To tape or not to tape windows? It depends on who is asked.

*With additional reporting by Daniel Beitler and Julie Zhu