"After 33 years it's time to rethink protected rooms"

Leading structural engineer Israel; David says direct hits on protected rooms require a revision of risk calculations but stresses that had the Iranian missiles hit buildings abroad, they would have collapsed.

"If I had to choose to be in a protected room, a stairwell or a basement - I would stay in the protected room. But after 33 years, it would be appropriate to rethink the issue of protection," says Israel Association of Engineers acting chairman Israel David, one of the country's most prominent structural engineers.

These days he is 'stuck' on vacation in Provence, and it is currently unclear when he can come home due to the suspension of flights to Israel. Even so, he is dedicating a large part of his time to treating and assisting in the inspections of the buildings that have been damaged during the war, through images and reports he receives from the sites of the damage.

David has long been critical of the Israeli concept of protection. "The issue of protecting buildings in Israel has existed since the War of Independence, and each time protection is handled according to what has happened, and not looking at what might happen," he says.

"During the War of Independence (1948), Egyptian planes bombed Tel Aviv from the sky, and from the east the Jordanians shelled with artillery from the Kalkilya area and reached almost as far as Tel Aviv. The lesson learned then was that a defensive system needed to be established that would serve the residents for a long time, and as a result, they built a lot of shelters - both in buildings and public shelters. The thinking was that during a long war, it would be possible to bring beds down there and spend time in the shelters.

"Then came the Gulf War (1991), which required getting down to the shelter within 60-80 seconds because of the missiles from Iraq. Then they realized that the shelter was not suitable, not because of protection problems, but because of accessibility. It is impossible to get down to the shelter in an 8-12-floor building in 60 seconds, especially in a situation where there are people with disabilities. That's when they invented the secure room in 1992."

What principles guided the developers of the protected room, and what is not relevant today?

"The scenario was that the protected room would not have to withstand a direct hit, but only a missile strike, which would hit 15 meters away from the protected room, but since then there have been completely different threats."

Why? The Iraqi Scuds were missiles, and the Iranian missiles are missiles. What's different?

"They are completely different. The accuracy of the Scuds was extremely low. They fired 35 missiles and hit one building; look what happened over the last week. There is a completely different situation here.

"In addition, the Iranians have thousands of missiles, with payloads that can reach two tons, which did not exist at all in the missiles of 1991. We need to think about changes in risk management and also from a technological perspective."

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What do you mean by changes in risk management?

"The basic assumption of the protected room, created as a result of risk management and probability calculations following the Iran-Iraq war, was that there would be no direct hits on the rooms. But this week we saw two or three cases in which protected rooms did take a direct hit. So should we stick with that basic assumption?"

Senior officers in the Home Front Command said last week that to protect against a direct hit, you need 3-meter-thick concrete. "They are admitting for the first time that protected rooms cannot withstand a direct hit. Personally, I would have stayed in a protected room, because the total number of direct hits from all the missiles launched at Israel have been few.

"But I still argue that after 33 years it is worth rethinking. At least do a brainstorming session to make sure that we are doing the best we can today, or maybe we can do something different. One thing is certain and important to internalize: we will never be able to do anything absolute."

"Surrounding damage within a radius of hundreds of meters"

Let's go back to the buildings that were hit by missiles. You've reviewed photographs and reports of the damage. What are your insights?

"If a missile like the one that hit the building in Petah Tikva, and the one that hit the tower in Tel Aviv, had hit buildings abroad, they would have collapsed. On the other hand, the building in Bat Yam and other buildings are old and built to poor standards, so the results of the missile strikes were different."

"The Tel Aviv tower is a lucky building. It is a special building. It has many protected rooms per floor because it has many apartments per floor. The architect designed it with a dense network of columns and horizontal beams, and not glass curtain walls, with columns 8-9 meters apart.

"And so, even though it was hit by a missile that I think is one of the heaviest there is, into the middle floor of the building - the building survived. The damage there is insane, and the missile hit a column that holds up 42 floors and cut it like a rope with scissors and yet the building survived.

"The Petah Tikva building also survived the missile that hit a corner with two protected rooms, and it is not an exclusive building, which was built about nine years ago.

"The survival of the new buildings is several reasons: the first - resistance to earthquake regulations; the second - stairwell protection that creates great reinforcement for the buildings, which, together with 4 or 6 protected rooms per floor, creates rigidity for the structure. In other words, the factors that make a building durable are not only the protected rooms, but a collection of engineering criteria."

"In addition, we see surrounding damage from the missiles, which reaches distances of hundreds of meters. We also treat buildings that were not directly hit and are almost a kilometer away from the impact. Although they were not damaged structurally, the curtain walls and interior finishes were damaged."

Published by Globes, Israel business news - en.globes.co.il - on June 22, 2025.

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