Invented by the Military for the Military

Envelop Protective Covers are the only product available that utilize the groundbreaking combination of breathability, waterproofing, and Vapor Corrosion Inhibitors (VCI) to eliminate corrosion and prevent environmental degradation. This technology was developed thru a U.S. Navy funded Small Business Innovative Research (SBIR) project to find a more effective way to protect exposed assets. Envelop Protective Covers were developed and patented as a result of the SBIR project.

Envelop is a custom fit cover that can be used on nearly any asset. The material is waterproof so that liquid water cannot permeate the cover from outside, however, water vapor can pass thru the cover. The breathable nature of the cover prevents the “greenhouse” effect while reducing condensation and keeping the metal surface dry.  Most Envelop covers also mitigate corrosion thru the use of a Vapor Corrosion Inhibiting (VCI) layer which emits ions that bond with water molecules preventing them from bonding with metal. This stops electron transfers thereby preventing corrosion. The ions do not bond with metal or optics nor do they affect electronics in any way.

The patented technology that makes Envelop so effective is the combination of breathability and VCI. Moisture vapor transmission, the measure of breathability, alone will not lower humidity below corrosive levels inside the cover if the ambient humidity is at a corrosive level. Without VCI, a cover has no ability to fight corrosion without lowering relative humidity under the cover to a level that is less than ambient. The way to most effectively protect an asset is to provide a cover with a vapor transmission rate that is high enough as to not cause a greenhouse effect while also incorporating a VCI for those cases where humidity is at a corrosive level. Envelop Protective Covers are the only product available that combines high moisture vapor transmission with a VCI.

The Envelop solution is easy to use, similar to traditional covers used by the military, however, Envelop’s cover technology has been shown to reduce corrosion by up to 95%. In addition to corrosion protection, Envelop will protect against moisture, sand, dirt, UV, airborne pollutants, heat, cold, FOD impact, and wind.

“Envelop Protective Covers are the only product available that utilize the patented, ground-breaking combination of breathability, waterproofing and Vapor Corrosion Inhibitors (VCI) to eliminate corrosion and prevent environmental degradation.”

Salient Characteristics

Years of research and engineering have created the most advanced protective covers available. Selected by the U.S. Army, U.S. Marine Corps, and U.S. Navy, Envelop Protective Covers represent the preeminent choice in equipment preservation technology.

Vapor Corrosion Inhibitor:

VCI layer which emits ions that bond with water molecules preventing them from bonding with metal. This stops electron transfers thereby preventing corrosion. The ions do not bond with metal or optics nor do they affect electronics in any way. VCI weave is inert and lasts for over five years. Reduces formation of corrosion by up to 95%.

Non-Porous:

The waterproof membrane cannot be clogged by microscopic sand, dirt, and dust fragments. This prevents diminished breathability over time and eliminates the need to regularly clean the inside of the cover.

Durable:

Robust materials perform exceptionally well in tensile strength, seam strength, tensile elongation, tear resistance, puncture, and abrasion testing. The materials are resistant to degradation from grease, oils, lubricants, and cleaning agents. Cover life expectancy is over five years for ground applications with some exceeding eight years.

Waterproof:

Water, rain, and precipitation will not penetrate the cover. Passes the water column at over 13, making the cover impervious to even the most severe driving rains.

UV Resistant:

Blocks 99.9% of UVA and UVB rays helping to preserve paint, coatings, wiring, grommets, and other sensitive components. Also keeps temperatures under the cover within twelve percent of the ambient temperature.

Mold & Mildew Resistant:

The materials scored zero on Fungal resistance tests, meaning they are not conducive to mold, mildew, and fungus growth. This protects operators from exposure to potentially dangerous substances.

Easy to Maintain:

The cover can be washed using soap and water and isopropyl (rubbing) alcohol. The materials will not absorb water ensuring ease of use for operators.

With Envelop

Without Envelop

Design Process

The design of Envelop Protective Covers is an iterative collaboration between Soldiers and Marines, Shield’s prior-service sales staff, and engineers. The input provided by each party means that covers will meet the rigid usability, performance, and quality standards that end-users have come to expect over the last decade. Additionally, designs are constantly being upgraded to keep pace with changes in training, operating environment, and the introduction of new technology.

The design process begins with an engineer capturing inputs for the design, then converting them to CAD files. This process reduces the time required from concept to finished product by increasing the accuracy of the initial design and including the necessary functionality in early-stage prototypes. Prototypes are fitted with Soldiers and Marines to ensure the designs are favorable for the operating environment in which they will be deployed. Weight, accessibility, operational firing capability, packability, ease of installation/removal, and storability are just a few of the dimensions which are optimized when covers are designed. Lastly, all feedback rendered from the end-users is incorporated to designs to help war-fighters maximize the benefit they receive from their Envelop Protective Cover.

“These covers were very effective, extremely easy to use, and greatly contributed to the howitzers being used for training in a minimum amount of time. Busting rust on the gun generally takes one hour. After removing the covers,it took less than 10 minutes. This allows us to spend more time training and less time pulling maintenance.”
Senior Instructor (SFC), U.S. Army

PM-TAS Specifications

The specification table displayed below shows the salient characteristics that were selected to protect the entire U.S. towed artillery arsenal. The PM for Towed Artillery Systems (PM-TAS) conducted a multi-year comprehensive evaluation of protective covers available, and determined that Envelop Protective Covers are the most effective method to provide long-lasting protection from dirt, dust, snow, wind, rain, UV rays, and corrosion.

Metric Notes
Vapor Corrosion Inhibitor (VCI) Minimum Effective Lifespan Greater than 5 Years
Moisture Vapor Transmission Rate (MVTR) Minimum 3,000 g/m²/24 hours ISO 15496
Wind Secure up to 75 mph Analysis
Waterproof Minimum 10m Hydrostatic Column ISO 811
Thermal Protection Maintain Internal Temperature within 112% of Ambient
Color Fade after Accelerated Weathering Less Than 2 NBS Units after 750 hours MIL-DTL-53039
Glossiness Less Than 5 Units at 60 Degrees ASTM D523
Tensile Strength (Warp Direction) Minimum 350 lbs/in² ASTM D5035
Tensile Strength (Fill Direction) Minimum 300 lbs/in² ASTM D5305
Seam Strength Minimum 30 lbs/in
Tensile Elongation Breaking Point Minimum 25% ASTM D5035
Tear Resistance (Warp Direction) Minimum of 20 lbs ASTM D2261
Tear Resistance (Fill Direction) Minimum of 23 lbs ASTM D2261
Abrasion No Defect After 19,000 Cycles using CS-10 Wheel with 500 g Load ASTM D3884
Bursting Strength/Puncture Resistance Minimum 700 lbs of Force ASTM 4833
Resistance to Accelerated Aging No Increase in Softness, Stiffness, Tackiness, or Brittleness, Nor Color Change when Exposed to 160 °F for 14 Days ASTM D3045
Wet Weight Maximum Weight Gain of 2oz per yd² 2 Hours After Saturation ASTM D3776
Hazardous Materials Non-Toxic to Skin, Eyes, or Epidermis CFR, Title 40, Sections 798.4100, 798.4470, 798.4500
Odor Maximum Rating of 2 SAE J1351
Flexibility Usable and Packable at Temperatures Between -40 °F and 125 °F
UV Radiation Cover Meets MVTR Requirement, 10,000 Cycles of Abrasion Testing, Maintains 60% of Strength Characteristics after 1,000 Hours of UV Exposure AATCC TM 186
Material Degradation Resistance Maintains Waterproof and Tensile Strength Requirements after Exposure to WTR Grease, Grease, Molybndium Disulfide, Hydraulic Fluid, Brake Fluid, Cleaner, and Lubricant
Corrosion Reduction Reduces Corrosion Formation by a Minimum of 90% Vapor Corrosion Inhibitors (VCI’s) actively reduce corrosion at high levels of relative humidity. ASTM D2136
Resistance to Low Temperatures Pass/Fail
Resistance to High Temperatures Pass/Fail
Mildew Resistance Rating of 0 ASTM G21
Flame Resistance Does Not Melt at Temperatures up to 219.2 °F. Will not Ignite at Temperatures up to 752 °F
“These covers were very effective, extremely easy to use, and greatly contributed to the howitzers being used for training in a minimum amount of time. Busting rust on the gun generally takes one hour. After removing the covers,it took less than 10 minutes. This allows us to spend more time training and less time pulling maintenance.”
Senior Instructor (SFC), U.S. Army

What makes us different—our patented, multi-layered technology

  1. Hydrophobic wicking layer pulls moisture from surface of equipment.
  2. Non-porous membrane eliminates intrusion of corrosion causing micro Sulfur Dioxide and Chloride molecules, while preventing clogging to maintain high breathability rates throughout the life of the cover.
  3. Vapor corrosion inhibitor (VCI) releases ion that prevents oxygen molecules from bonding with equipment, reducing corrosion up to 90%.
  4. Durable outer material is waterproof, breathable, and 100% UV resistant—allows moisture to evaporate outward, thereby preventing the greenhouse effect.

How It Works

Superior Performance Proven

In recent independent head-to-head testing, Envelop Protective Covers were proven to be the most breathable and durable product on the market.

  • Tearing strength
  • Breaking strength
  • Abrasion cycles to failure
  • Puncture resistance
  • Seam strength

Mechanical Testing Review

Cover Mechanical Properties Comparison
Conducted by Independent Laboratory – 2013