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Our Modular Framing System

Since 2002, TotalShield has been the leader in blast-resistant products. Our clear modular enclosures have helped companies and organizations such as NASA, SpaceX, Blue Origin, and Exxon Mobile safely conduct potentially hazardous industrial processes and test procedures, and to protect personnel from equipment failure.  

Unlike most steel enclosure options, our blast shields are manufactured with polycarbonate panels mounted on a modular framing system. But how did we design such innovative shielding enclosures? 

Unique industrial needs require new, unique solutions. With that in mind, Keith Snyder, the mastermind behind our products, went to work.

Designing Our Clear Modular Enclosures

During his time as a Senior Member of the Technical Staff at Sandia National Laboratories, Keith was assigned to an ongoing project to develop a steel containment room around a centrifuge. Soon, he realized the costs were high, maintenance would be costly, and the inability to see into the room posed a safety risk. It was then that he started considering polycarbonate panels.  

“At the time, I was researching polycarbonate for a greenhouse I was building at my house. The material was relatively new and not widely used,” says Keith. “Some manufacturers were developing a thin polycarbonate panel for greenhouses for its transparent and high impact-resistance capabilities. And I thought to myself, we are a national laboratory, we should use new technology”, he notes. 

Assembly of a TotalShield’s modular machine shield.

Keith then designed a modular system with aluminum and steel framing, and started testing it with polycarbonate panels. After reviewing the results, it was clear that the new system was superior to legacy safety enclosures.

“Everybody loved it! We could actually see the machine through the containment, which is not possible with a concrete or steel room unless you have cameras,” Keith declares. 

How Our Modular Framing System Works

Polycarbonate is a very strong material. However, it can fail under high-energy conditions, especially if force is applied to a small area. If a polycarbonate panel is rigidly held in place, it absorbs a large percentage of the impact energy and can fail. However, if the panel is allowed some freedom of movement and deformation, more of the impact energy is dissipated, and the panel is less likely to fail.

Similarly, if the framing system is rigidly welded together with no freedom of movement, it is less able to dissipate ballistic and explosive blast energy.

Close-up of the bolted connections on a TotalShield’s polycarbonate shield enclosure.

This is why the TotalShield framing system is designed as a bolted modular assembly made up from smaller sub-panels. This allows impact energy to be dissipated within the framing, and allows the polycarbonate panels to individually flex in their sub-panels without failing. 

Put simply, by allowing the panel to transfer the energy to the frame, the gasketed framing system allows the polycarbonate panel to handle even greater impact energy density.

The modular system offers another benefit: reducing costs and time. 

In a scenario where a panel is disfigured or fails, you can simply replace that specific panel by unbolting and replacing the sub-panel, rather than a costly welding or patching process for a steel or concrete containing room.

Portability and Assembly Advantages

Keith also realized that legacy steel and concrete protective shielding rooms were very heavy, and this made their transportation, installation, and assembly very costly. In addition, once installed they became nearly impossible to move or reconfigure without tearing down the entire installation.

“I wanted to design a system that two people could assemble and install with minimal equipment, without requiring massive changes to the facility, and that could be moved if needed,” Keith explained. “To achieve these objectives, I knew the framing system needed to be made of lightweight but strong materials, and it needed to be modular.”

To meet this objective, the TotalShield framing system was developed with a steel structural frame, and with aluminum panel framing. Incorporating aluminum into the framing system dramatically reduces the overall weight of the structure. By sizing the polycarbonate panels strategically, we are able to keep the sub-panel weight low enough to be easily lifted and bolted into place by two people.

Unlike heavyweight steel or concrete blast rooms, the TotalShield system does not require reinforcement of the floor slab and heavyweight cranes for installation. The modular design also allows for easy disassembly and reassembly of the room when it needs to be moved or reconfigured. Due to the nature of the construction, building permits are often not needed for the installation of a TotalShield enclosure.

Blast and Overpressure Capabilities

We have covered ballistic-resistance standards for the most common thickness of polycarbonate panels. As we have mentioned, when comparing different ballistic standards, there is a wide disparity between them. 

In the following table you’ll find a comparison of all the major ballistic standards. 

Polycarbonate Thickness (Gauge) (inches)UL 752NIJ 0108.01ASTM F1233HPW TP-0500-02
0.375Not ratedNot ratedHG1Level A
0.500Not ratedNot ratedHG1Level A
0.750Level 1Not ratedHG1Level B
1.00Level 2Not ratedHG1Level B
1.25Level 3Level II
Level IIA
HG4Level C
1.25 polycarbonate/acrylic laminateLevel 6,
Supplementary Shotgun
Not ratedR3Unknown

These standards add another problem: these testings were made considering small projectiles moving at high velocities, but most of the industrial procedures involve larger projectiles traveling at slower velocities. It is essential to notice this difference since these impacts cause greater deflection of the polycarbonate panel and impart a relatively higher force on the frame. Our products need a different testing procedure to calculate the resistance level required. 

That is why we rely on our own testing database, which includes compiled impact and blast testing results we have compiled for over 20 years. Our database allows us to analyze our customers’ specific requirements to determine the level of protection required for their business applications. 

Proudly, TotalShield took this leadership and developed a more economical and high-impact-resistance solution for industrial applications. For over 20 years, we’ve manufactured certified impact-rated polycarbonate enclosures, and we’ll continue to do it while keeping our commitment to deliver safe, reliable, and tested protection. 

Now that you know how our modular framing system works and how it’ll help to keep your personnel and machinery safe do not hesitate to contact us to work on a custom quote for your business application. 

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