What Happens to the Force After a Projectile Hits the Fabric

When someone watches a video of an impact test, attention goes straight to the center of the screen. A 2x4 is fired, it strikes the protection, and the question looks very simple: did it go through or not?

That image is useful, but it leaves out the part of the engineering that interests me most.

After the impact, where did the force go?

It did not disappear. If the projectile did not pass through the fabric, that energy had to move through the system. First it deformed the weave. Then it traveled toward the perimeter. From there it passed into the connection, into the screws, into the anchors, and finally into the concrete, steel, block, or masonry of the building.

That route is called the load path. Understanding it completely changes the way you evaluate hurricane protection.

A Strong Fabric Cannot Keep All of the Force

Think of a hammock. If someone drops into the center, the fabric takes the weight, deforms, and distributes the load toward the ends. The weight ends up reaching the points where the hammock is tied.

A flexible hurricane screen works on a similar principle, although the forces and the engineering are obviously far more demanding.

When wind or a projectile loads the fabric, the membrane deforms. That controlled deflection lets part of the energy spread over a larger surface. But all of that force eventually looks for a way out toward the perimeter.

That is where the work of the connection system begins.

This is why, in Technical Testing, Engineering & Certifications, we insist that HS-1500 should not be evaluated as a piece of high-strength fabric. The fabric is the first component in a chain.

The Perimeter Is Where the Load Gets Organized

One of the least visible parts of a screen is the perimeter reinforcement. It is, however, where the force distributed by the fabric begins to concentrate in order to reach the connection points.

If the perimeter is poorly fabricated, if the seams do not match the stress, or if the geometry does not distribute the load correctly, the problem can show up before the force even reaches the anchor.

That explains why two screens made from similar materials can behave differently. The raw material may be equivalent and the edge design completely different.

In a flexible system, the engineering is not about preventing all movement. It is about controlling how much movement occurs and how that movement turns into loads the next components can receive.

The Flexible Clip Does Not Remove Force; It Changes How Force Arrives

Here is one of the differences that matters most to us at Hurricane Solution: the flexible connection.

A rigid point tries to stop the movement of the membrane more abruptly. Depending on the geometry, that can concentrate a considerable load in a limited area. A well-designed flexible connection allows part of the movement to continue in a controlled way while the energy is distributed among several points.

We are not “removing” the force. We are changing the way it is transmitted.

That principle is explained in depth in The Patented Anchoring System. To me, it is one of the reasons flexible anchoring should not be presented as an accessory. It is part of the structural behavior of the system.

After the Clip Comes the Piece Almost Nobody Looks At

The next stage is the screw and the permanent anchor. This is where the system stops being primarily textile and starts depending directly on the building.

An anchor may be only a few centimeters long. Yet at that point, the load accumulated across a considerable portion of the screen is entering the concrete.

That is why it is not enough to say “we use strong anchors.” You have to know which anchor, which screw, what embedment depth, what spacing between points, and what material exists behind the finish.

In Certified Anchors & Component Integrity we develop this part with pullout test data and component documentation. It is a conversation the Mexican market needs to have far more often, because anchoring tends to be the place where a certified system can be undermined during installation.

The Building Is Part of the System Too

This may be the least intuitive idea for an owner: the last component of hurricane protection is the building itself.

There is no anchor that floats in the air. It is installed into some substrate.

Reinforced concrete, hollow block, solid masonry, and structural steel do not behave the same way. Neither does new concrete behave like concrete with years of exposure to humidity and salt near the ocean.

If the substrate is deteriorated, if the anchor is set too close to an edge, or if the depth is insufficient, the system can have excellent material and an excellent clip and still fail to achieve a safe load transfer.

That is why a serious evaluation starts by looking at the building. Protection is designed from the structure outward, not from the catalog inward.

What Changes When the Wind Keeps Blowing for Hours

So far we have followed a single impact. A real hurricane does not end there.

After the strike, the wind keeps loading the screen. Pressure rises and falls. Direction can shift. The fabric keeps moving, the perimeter keeps working, and every connection takes thousands of load cycles.

That is another reason to understand the full path of the force. A point that handled an initial strike perfectly can fatigue if repeated loading was not considered in the design.

This is why impact and cyclic pressure are separate tests. One answers “did it survive the strike?” The other answers “did it keep working afterward?” For a real property, both questions matter.

The Example of a Large Sliding Door

Picture a four-meter sliding door facing the ocean. The protection panel covers a significant surface. When wind loads that fabric, the total force can be considerable even if the pressure per unit of area looks manageable.

The fabric deforms. The perimeter distributes. The clips receive. The screws load the inserts. The inserts transfer into the concrete.

If any one of those steps was sized with only a small window in mind, the problem will appear at the link that does not have enough capacity.

This is one of the reasons I dislike the phrase “we place an anchor every so many centimeters” as a universal rule. Spacing depends on the system, the opening, the exposure, the geometry, and the substrate.

How Someone Who Is Not an Engineer Can Evaluate This

You do not need to calculate the loads. It is enough to ask questions that force the vendor to show they actually thought about them.

I would ask:

• Was the fabric tested as part of a system, or only as a material?
• How is the perimeter reinforced?
• Is the connection rigid or flexible, and why?
• Which anchor and which screw will actually be installed?
• What substrate will they go into?
• How is the spacing between anchors determined?
• Is there documentation for the complete configuration?

If the answers always stop at “the fabric holds X PSI,” the explanation is incomplete.

One More Detail: The Distance Between Screen and Glass

The load path also helps explain why the fabric should not be installed flush against the glass. A flexible membrane needs room to deflect. If the clearance is insufficient, the screen can do exactly what it was designed to do — move and absorb energy — and still end up striking the glass it was meant to protect.

That is why installation geometry includes standoff, not just width and height. In deep openings it is relatively easy to achieve. In window walls that sit almost flush with the facade, on narrow balconies, or around complex architectural details, it may be necessary to adjust where the anchor points go.

This is another example of how a good product can be badly installed. The certification describes a configuration; the installation has to respect the space that lets that configuration behave the way it was designed to.

Closing

When a projectile strikes a hurricane screen, the most visible question is whether the fabric tore. The engineering question is what happened to the energy afterward.

That force has to travel a complete path: fabric, perimeter, flexible connection, screw, anchor, and structure. The real strength of the protection depends on all of those elements being compatible, and on each one being able to receive the load handed to it by the one before.

That is why good protection cannot be understood by looking at the weave alone. It is understood by following the force all the way into the building.

Read the full system engineering analysis at Hurricane Solution →