The Building Is Our Last Line of Defense: An Interview with Eve Hinman

When Vauban, Louis XIV’s chief military engineer, first planned and constructed a network of fortifications around the perimeter of France in the 1660s and 1670s, a new idea of the state as an impregnable fortress was being advanced. More than three centuries later, the fantasy of such simple geographies no longer holds sway. The center and the periphery, the inside and the outside, now overlap in non-linear patterns, dismantling Vauban’s dream of an invincible and secure inside. From Cold War Berlin to current day West Bank, from the Mexican-American “border” that cuts deep into the American South to almost every American city shredd­ed by class and race divisions, what we see instead is that the border, as both psycho-geography and reality, refuses to remain at the edge of the nation-state. The threat of domestic terrorism, homegrown or foreign, is now the most visible mode in which the border mentality manifests itself in the US; the bomb is its most spectacular weapon.

In such a world, “the building is our last line of defense,” as Eve Hinman of Hinman Consulting Engineers (HCE) puts it. HCE, whose clients include the FBI, The Pentagon, USAID, and the State Department, is one of the leading companies in developing blast-resistant buildings. Sina Najafi and Eyal Weizman met with Eve Hinman in New York to discuss the technology and objectives of “hardening” buildings. ­

We would like to start by understanding what a blast does to a building. Can you give us a kind of slow-motion description of the event following the detonation of a bomb outside a building?

Well, an explosion is a chemical reaction that causes an extremely rapid release of energy. This energy is released in several forms: sound, heat—visible as the “fire ball”—and shock waves, consisting of highly compressed particles of air propagating radially outward from the explosive source at supersonic velocities. Of these, it is the shock wave that is the primary cause of the structural damage. Released energy pushes the air particles out. In addition to going into the air, it also goes into the ground, and creates a crater. Some energy propagates through the soil as well, creating “ground shock” that can shake buildings, like a high-intensity, short-duration earthquake. The shock wave exerts extremely high pressures on all surfaces that it encounters in its path. The side of a building facing the explosion is worst hit by the shock wave because the wall breaks the wave and forces it to reverse its direction amplifying the peak pressure like ocean waves against a particularly weak wave breaker. The shock wave travels across and through the building, and in the process pressure is applied on all the surfaces it encounters. After the initial shock wave, a wind rushes in to fill the vacuum created, carrying high-velocity debris which can cause impact damage.

How do different elements of a building—concrete, steel, glass—respond to an explosion? What are the factors that quantify the damage of an explosion?

The glass breaks almost immediately as the shock wave hits it. The exterior walls will bend inward and possibly also break. Once the blast wave has entered the interior of the building, it will flow both upward and downward and act on the floor slabs of the building. Since the floor slabs have not been designed for upward load, they are particularly vulnerable to collapsing in this direction. If the force of the explosion is capable of failing a floor slab or column on the lower floors, then a partial or complete collapse of the structure may be initiated as the floors above come tumbling down. This “domino effect” is known as “progressive collapse.” The vast majority of fatalities occur in the collapsed portion of the building.

The skin of the building is usually the most fragile part. These days, buildings tend to be very, very thin, almost all glass and aluminum. So the skins are very fragile and are crashed by the blast wave almost instantaneously as it enters the building. Generally, it is quite hard to knock out a column because columns do not have much surface area, and the blast is looking for a surface, so it just kind of washes around slender members like water. For a steel building, what you might see is that the framing tends to stay in place—the beams and columns—but all large surfaces, like floors and walls, are swept away.

And what does this pressure do to a human being?

If you’re hit by the pressure alone, it may cause lung collapse, which can be lethal. Ear drum rupture is another possibility, but that’s usually not lethal. The collapse of the building is the primary cause of fatalities. People on the lower floors may be trapped in little void spaces and be saved if the rescuers are able to get to them quickly. People who are near the window are in most danger. They are the first to be hit by flying bits of glass, causing lacerations; their lungs may collapse, their eardrums may rupture, and the building may fall under or on them.

So the corner office must be the most dangerous place in the building. Should we now be rearranging buildings so that storage spaces are near windows and offices closer to the building core?

No, people are not willing to give up windows. What we recommend is that at a minimum the VIPs’ offices not be prominent. In other words, if you see the face of a building, there should not be some huge multi-story area where it’s clear that something special is going on. We don’t want to call attention architecturally to the part of the building where there are going to be people who are likely to be targets. Regarding glass—what we’re finding is that glass wall systems have more ability to absorb blast energy than previously thought. And we’re using laminated glass so that it’s less hazardous. Still, glass affords a relatively low level of protection.

When did individual buildings first become targets in a significant way? In the 1970s, there were airplane hijackings and bombs in public spaces, but I don’t remember buildings being bombed.

There were three main stages in the development of targeting and protection of buildings. The bombing of the US Marine barracks building in Beirut in 1983 was the first and one of the biggest truck bombings ever. Shortly thereafter, the US embassy there was also bombed. After that, the US started to work on protecting embassies from car bombs. The 1993 World Trade Center bombing and the 1995 attack that destroyed the Murrah Federal Building in Oklahoma City brought the threat into the US itself and federal and landmark buildings became fortified. Then there was the 1996 Khobar Towers bombing in Saudi Arabia, and the 1998 embassy bombings in Nairobi and Dar-es-Salaam, and finally 9/11, which inaugurated the corporate world’s serious interest in security.

Up until Beirut, the US State Department was mainly concerned about mob attacks—people climbing over the walls and infiltrating the embassy. Beirut was, by the way, one of the first suicide attacks, and it was a huge event—about 12,000 pounds of TNT explosive, which is still one of the largest vehicle weapon that has ever been recorded. So, with the US embassy being bombed, the State Department developed a set of new of criteria for architectural security, and that is how I started to get involved in this subject. I was working at the firm that developed those criteria. This was the first document of its type and our work was immediately applied to several embassy buildings.

One of the main criteria we asked for was a 100-foot setback from the road, because shock waves decay extremely rapidly with distance, and also that buildings be built of reinforced concrete, which is how bunkers are built. The windows were designed to keep all of the blast pressure out. They were very thick in order to be blast-resistant.

But these changes affected a very small inventory of buildings. The Department of State owns about 400 embassy buildings. It was only the beginning.

Was that the first time you worked on blast-resistant engineering?

When I was hired, I was doing defense work. I was designing nuclear missile silos and barracks in various NATO countries. But after Beirut, my work changed from the field of “conventional” and nuclear warfare to give answers for threats of unconventional, terrorist, and guerilla warfare.

How was Oklahoma City seen in relation to this “history” of the targeting and hardening of buildings?

After the Oklahoma City explosion, domestic federal buildings were hardened. I was again part of the panel that developed a new set of criteria and recommendations to tackle that. From that moment, the tendency was to take the federal building—and this later influenced the state department’s buildings abroad as well—outside of city centers and into suburbs. There we were much more flexible in terms of our considerations; we could afford to get rather insulated compounds with large setbacks from the public areas, with wider views all around. The density of the city exposes the building to a high degree of risk.

The domestic federal building inventory overseen by the DSA—the largest landowner in the country—includes about 4,000 highly populated buildings, which was still a relatively small market.

A lot of inventors have begun testing new materials, new security and control systems to resist explosion effects. These were implemented with lower and lower budgets. Innovation in this field has accelerated after the 1996 bombing of the Khobar Towers because at that point the military started to get involved, and its budgets and expertise were harnessed to improve knowledge and procedure. So, then all of a sudden, the barracks, buildings, and training facilities on military compounds both in the US and abroad were being hardened.

So if Beirut initiated the protection of embassies, Oklahoma brought about hardened federal buildings, and the Khobar Towers set in motion the securing of military installations, did 9/11 bring that into the corporate architecture of the private sector?

Before 9/11, there was a little bit of interest from the private sector until they found out how much it cost, and then they would go away. But after 9/11, the private sector is seriously taking up these concerns, particularly with their underground parking. September 11 also opened up the market for infrastructure protection: bridges, tunnels, train stations, petro-chemical facilities, banking institutions. Within the private sector, we’re seeing activity mostly with banking institutions, insurance companies, and signature buildings in the city. In a small city in the Midwest, they may have only one 50-story building, but it’s the tallest building in their state, and they think it’s a target, and they want us to help them.

Did this security mentality filter into contemporary architectural and urban practices? Does the government favor lower buildings now, for example? Are there significant changes in the way cities are organized and do you advise on changes at that level?

Yes, for example, government officials always talk about cars—how to stop cars ramming into buildings, how to stop cars from getting under buildings and blowing up, and so on. But why, especially in a place like Washington, D.C., do we really need cars at all? Why don’t we just get rid of the cars? Nobody wants to talk about that, because we’re so reliant on vehicles, particularly in this country.

Another thing is that now when we ask for 50-foot setbacks for federal buildings, there’s more green space, and this is good for the environment. In a sense we are starting to see blast-resistant sustainable buildings.

Safety can be enhanced through architectural countermeasures, and can be the least expensive way to protect buildings. We provide functional and structural design solutions for windows, entrances, and layout that optimize protection without creating a building that looks like a fortress. We usually consider moving vehicle and stationary vehicle bombs, hand-carried weapons, and ballistic weapons. We work through “what if” scenarios and make recommendations for improving safety accordingly.

It’s interesting how aesthetics is so quick to accommodate the new agendas—security features camouflaged as public art.

I find that when I explain concepts of blast to architects, some of them are interested and some of them aren’t. And those who are interested will come up with all kinds of creative solutions to these issues, particularly landscaping features. For the Seattle Federal Courthouse, we designed essentially an obstacle course between the street and the building at the front entrance. We placed a grove of trees, and then a sunken sculpture garden and then a monumental staircase and then this cascading fountain. It wasn’t completely ram-proof technically—it doesn’t stop a vehicle from getting to the building—but it makes it so difficult that it would deter most people from trying.

Do you know Richard Serra’s public sculptures? They’re probably very good for this purpose…

But they tip over easily. We did do something related to Serra with the Liberty Bell. After 9/11, we were working with an architect who wanted to protect the bell! And I was like, “An atom bomb could go off and this bell should still be here.” I mean, it’s a big bell. But anyway, they had curved, steel walls on opposing sides of the bell to protect it, using your Serra concept. The walls were connected into the building frame.

But it wasn’t by Serra, was it?

No, but it was using the ideas he’s advanced.

We’ve seen on your webpage that you actually collaborated with Morphosis, Tom Mayne’s architecture firm on a Federal Office Building in San Francisco. When you work with contemporary, cutting-edge architects, do you find that it’s easier to integrate security concepts into their rather complex buildings?

Morphosis was a fabulous group to work with. They are just very smart architects, and very responsive. I remember going to a security meeting where security was telling them, “You can’t do this, this, this, and this,” for various security reasons that really didn’t relate to us. These security considerations had to do with the fact that the building was located in a bad neighborhood, where, as you know, there are homeless people who like nooks and crannies where they can sleep or hang out. And that was considered a threat. The architects just totally changed their design in response to these “threats” very, very quickly and responsively. With some architects, it’s just like in stone. If they’ve drawn it on a piece of paper, that’s it. You can’t change it, and you end up coming up with some clunky security solution because they can’t move a wall around.

You know that in May 2003 there was a shootout with a gunman at a Gehry-designed building on the campus of Case Western Reserve, and afterwards the SWAT team had complained about the building, saying that all their training for sweeping buildings and for returning fire assumes a specific kind of architecture. “There are no right angles in the building,” was the complaint of Chief Lohn of the Cleveland police. Do you have any thoughts about that?

There’s a whole discipline called CPTED—Crime Prevention Through Environmental Design—which deals with how architecture can thwart criminal activity. Things like little nooks and crannies of the building where people can pull somebody into and nobody will see them are discouraged.

From a purely explosive perspective, we would like more of a convex shape rather than a concave shape—something like a hemisphere would be good—to reflect the pressure away.

So Gehry is good?

Well, he’s got both the concave and the convex. What happens in the concave areas is that the blast pressure reflects a lot and it amplifies. It’s also important to have a very stable construction, such as a pyramid shape.

The arms race between security and terrorists has shown sometimes that the more security, the more violent the attacks tend to be. This is how plane hijacking got radicalized since the 1970s. Do you not think that perhaps security and prevention could be counterproductive in a certain way?

Yes, this is why we want the protection to be as unobtrusive as possible, so as not to draw attention to the building, or turn it into a fortress, which may cause threat escalation. For federal buildings, they still want the buildings to keep a feeling of openness, which they think is consistent with what democracy is about.

When you say “unobtrusive,” do you mean to protect the building without signaling that it has to be protected in this particular way? Because, presumably, part of the way security works is that you also announce it loud and clear: “This building is secure.” Or no?

No, no. Building owners, I’d say, uniformly do not want attention brought to their building, and they do not want anybody knowing that they’re upgrading their buildings security-wise. They don’t want to make any announcement to draw attention to themselves—that already makes them more of a target. I’d say within certain sectors, some clients go way out of their way to make protection measures look like routine maintenance or to disguise it as something else.

From the government’s perspective, by fortifying one building, you actually direct attacks to other, less fortified ones. In that respect, the government applies what it calls the “good neighbor policy,” whereby if they have a little fort in the neighborhood, they feel they are making the rest of the neighbors more vulnerable.

When we were doing the embassy criteria, we decided that we must provide the same level of protection for all our embassies, because by not providing protection to one embassy, you’re creating a vulnerability that will draw attacks. On the same level, if you harden a building in Manhattan, you must be careful that you are not driving terrorists into smaller towns in search of targets.

As you mentioned, there were initially 400 embassies protected, then came the 4,000 federal buildings, then the much larger inventory of armed forces installations, and now the private sector. Now that all these are secured, what is left soft and unsecured is much more threatened and must also invest in security. If you secure one thing, you finally have to secure everything. The logic of endless fortification means that Vermont has to be as fortified as Manhattan and Iraq. And even if you secure all buildings, the people in the subway might be targeted instead. Where does all this end?

There has to be a distinction between what we are doing domestically and what we are doing in war zones. Domestically, you want to have at least the appearance of a uniform level of protection to keep out the “lazy terrorist,” to deter the most obvious simple-minded and yet devastating execution of events, which means parking a Ryder truck 10 feet away from the building and detonating thousands of pounds of fertilizer bomb. Certainly, there have to be measures to keep weapons away from the building because it’s just too easy to execute. Eliminating that scenario is the goal, rather than trying to stop airplanes from flying into a building.

But “buildings as targets” have a longer history than that of contemporary terrorism. You’ve said that the terrorists don’t abide by the rules of warfare. We completely agree. But I think that warfare itself has not abided by the rules of warfare for a long time. Bombing civilians has been going on on the good guy’s side as well for a long, long time…

The difference is that the terrorist event is a relatively low- budget single event; The 9/11 events, I forget how much they said it cost, maybe a couple of hundred thousand dollars...

Does this industry have an end point?

You must understand that all this depends as well on a growing market that pushes security as a product. Because basically the economy isn’t doing that well, and everybody thinks that there’s money here, everybody is all of the sudden a security expert—and convinces building owners that they are under threat.