Bunk House Structures: The Future of Inflatable Shelters

Bunk House Structures represent a significant leap forward in inflatable shelter technology. Drawing on 15 years of field experience and customer feedback, these structures utilize Drop Stitch technology. This technology delivers exceptional strength, durability, and insulation that traditional shelters simply can't match. While the materials and design are revolutionary, the fundamentals of keeping your shelter securely anchored remain critical. In this guide, I'll walk you through proper setup procedures and explain the engineering principles that make these recommendations so important.

Emergency Shelters Built for Real-World Missions

Inflatable emergency shelters serve diverse roles. They can be used as field hospitals, command posts, drive-through distribution points, and temporary emergency housing. Bunk House Structures are constructed using Double Wall Fabric (DWF), also known as Drop Stitch technology. These shelters inflate in minutes using air pumps and require minimal personnel and training to deploy.

Setting up your structure is straightforward. Our YouTube channel features comprehensive how-to videos covering our structures and accessories. To help untrained personnel get started quickly, every structure includes a QR code that provides direct access to these training videos.

Understanding Wind Safety

While our tents are engineered to withstand significant wind forces, safety must come first. I recommend deflating and evacuating the tent when winds exceed 35 mph to protect occupants from airborne debris. That said, our engineering analysis and DWF stress testing demonstrate that these structures can handle wind gusts up to 65 mph when properly anchored.

It's worth noting that there's currently no industry-standard wind rating for temporary inflatable air tube structures. The ASTM F2374-17 addresses safety standards for inflatable amusement rides, and ASCE 7-10 covers engineered wind loads for various building types. However, temporary inflatable structures fall into a gray area. This means that wind ratings from different manufacturers may not be directly comparable or entirely reliable.

The Critical Role of Stakes and Anchors

Here's the fundamental truth about wind resistance: your tent's ability to withstand wind depends entirely on your stakes and anchors. The key measurement is pullout capacity, which represents the force required to remove a stake from its secured position in the ground. This capacity, combined with your anchoring straps, directly determines whether your tent stays grounded during high winds.

The pullout capacity calculation follows this formula:

P = Pb × Ce × Cf × Ci × Cl × Cd < 2500 lbs.

Breaking this down, P represents your pullout capacity, while Pb is the baseline pullout capacity for a standard stake. The other factors are correction values for embedment depth (Ce), fastening height (Cf), stake inclination (Ci), load angle (Cl), and stake diameter (Cd).

Our 36-inch stakes start with a baseline capacity of 800 pounds when driven into stiff or medium-dense soil. The traditional 12-inch stakes commonly used with Bunk Houses work for normal conditions. However, when you're preparing for extreme wind, you'll want to upgrade to cement blocks, cement anchors, 36-inch stakes, or anchor plates.

Let's look at a practical example. Using the formula with realistic deployment conditions—assuming 30 inches of embedment depth, a 2-inch fastening height, a stake angle between 0 and 15 degrees, a slightly smaller than 1-inch stake diameter, and a 45-degree angle of pull—we calculate:

P = 800 × 0.76 × 0.97 × 1.00 × 0.9 × 1.00 = 530.784 lbs.

This means each properly installed 36-inch stake provides a pullout capacity of approximately 531 pounds.

Real-World Wind Load Analysis

When we apply a hypothetical 65 mph wind speed to a Bunk House, the resulting wind load equals 1,093.5 pounds. Using eight stakes (four upper and four lower), we achieve a total anchoring capacity of 4,246.32 pounds against that 1,093.5-pound wind load. That's nearly four times the wind force acting on the broad side of the structure.

However, direct wind load tells only part of the story. The moment, or rotational force, created on the structure is equally important. Our wind modeling shows that a 65 mph wind creates a maximum moment of 6,650 pound-feet on the structure. Calculating from the structure's center point, you need an anchoring force of 950 pounds to accommodate this full moment. When distributed among four anchoring points, each stake location must hold a minimum of 237.5 pounds. This is why we recommend concrete blocks, anchor plates, full 55-gallon water barrels, or 36-inch stakes as anchors. While 12-inch stakes may hold in ideal conditions, if there's any question about ground strength, a 36-inch stake is the safer choice.

Environmental Variables That Matter

Selecting the right location significantly impacts your setup's stability. Whenever possible, find an open, flat space free of debris. Firm grass provides optimal conditions because stakes can be driven deep into the soil. Asphalt and concrete surfaces also work well. Rocky terrain and concrete present unique challenges but can be addressed effectively using drive-on anchor plates weighted with vehicles.

Water barrels offer effective anchoring in many situations, but they may begin sliding on asphalt and concrete surfaces due to the friction coefficient. In these scenarios, they don't provide as much holding power as anchor plates.

Soil type plays a crucial role in stake performance. Medium-dense consistency offers the best option. If the soil is too loose or muddy, stakes are more likely to shift under stress, compromising your entire anchoring system.

Best Practices for Staking

When staking your tent, three factors demand your attention: depth, angle, and soil type. Whether you're working with 12-inch or 36-inch stakes, remember that deeper embedment creates a sturdier setup. Drive the stake straight down or vertically into the ground with no visible angle. In most cases, a mallet or sledgehammer will provide the best results for securing stakes properly.

Understanding D-Ring Capacity

The D-rings—metal rings that serve as attachment points for loading straps—represent another critical component of your anchoring system. These rings secure the structure and protect against winds and other forces that might cause excessive movement.

To verify the stress capacity of our tent materials, we conducted failure testing on DWF panels with attached D-rings. Using a mechanical press to pull the D-rings apart, failure occurred at an impressive 600 pounds. A video of the test is available here. The test results demonstrate that a Bunk House has a total anchoring capacity of 4,800 pounds, calculated as eight D-rings multiplied by 600 pounds each.

Anchoring on Asphalt and Concrete

While stakes work perfectly on grassy areas, you'll need alternative anchoring methods when setting up on gravel or concrete surfaces.

Water barrels or water bladders are containers that, once filled with water, function as weighted anchors. The more water you add, the heavier the anchor becomes, allowing for substantial holding power. Water barrels are easy to transport but require access to water for filling and maintenance. Water bladders operate similarly but are more prone to movement.

A common misconception deserves clarification: a water barrel weighing 500 pounds doesn't necessarily provide 500 pounds of anchoring force. A generally smooth plastic bladder typically has a friction coefficient around 0.4. This means the effective anchoring weight of a full bladder is only about 192 pounds. Another consideration involves the attachment height on the barrel—excessively high attachments may cause spillage or tipping.

Concrete blocks provide another anchoring option. While this is a straightforward solution, these blocks can be labor-intensive to move and secure. Check with your local rental company for availability and transportation options.

Drive-on plates offer a unique and elegant anchoring solution for your Bunk House Structure. Constructed from steel and painted safety yellow, these plates allow vehicles or other heavy objects to serve as the anchor weight while providing secure attachment points for straps. This method is particularly effective on hard surfaces where traditional stakes can't be used.

The Bottom Line

Proper anchoring isn't just about following guidelines—it's about understanding the forces at work and making informed decisions based on your specific conditions. Whether you're deploying in an emergency situation or setting up for planned operations, taking the time to anchor your Bunk House Structure correctly ensures both safety and performance.

Read the full documentation this article was derived from here:

BHS Staking Document.pdf

Download PDF • 6.25MB

For more information about Bunk House Structures, visit BunkHouseStructures.com or email info@bunkhousestructures.com.