Скачать или смотреть History of EPS Foam (Aka Styrofoam Foam) Floatation / Flotation Devices Expanded Polystyrene Boat

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Introduction

Expanded polystyrene (EPS) can be used for a variety of floatation devices, such as rafts, docks and billets. Buoyancy billets are usually produced in standard sizes but can be easily customized. They are suitable for fresh and salt water and are unaffected by winter temperatures. EPS billets can support 55 lbs. per cubic foot, which is significantly more than typical wood floatation devices. Since EPS is lightweight and easy to work with, installation and maintenance costs are low.

EPS buoyancy systems are safe for the environment. They are ozone friendly, no CFCs are used in their production, and they have no food value for marine animals. Growth of marine life in stagnant water does not impa
ir the buoyancy of the billet and can be easily removed with a scraper.

EPS floatation structures exhibit excellent rebound characteristics with minimum rocking, provide less resistance to breaking waves and are quieter than those with other types of floatation such as drum floats.

Floatation:

In summer months, it is not unusual to find the nearest watering hole filled with people escaping the heat and enjoying the water as well as sights and sounds. Many water-related activities are made safer with the use of expanded polystyrene (EPS) from floating docks to life-saving devices and buoys to surf and boogie boards. Whether you recognize it or not, EPS is everywhere on the waterfront.

Floatation devices have evolved over the years due to the introduction of new materials. Prior to the invention of foam plastics, in the early 1960s, wood or empty drums were commonly used in floatation docks. Due to its lightweight and buoyant characteristics EPS has become the most popular floatation product on the market today.

With a life expectancy of twenty years for exposed EPS, manufacturers began experimenting with various coatings to protect it from petroleum products floating in the water and to prolong its lifespan. The blocks were painted, encased in steel or aluminum, wrapped with fiberglass or covered with wood. By the 1990s, the Army Corps of Engineers recommended and implemented regulations to require encapsulated foam in all marine installations. Approved coatings or encapsulations were at the discretion of each reservoir manager making it tedious for manufacturers and distributors to market their various products. Appendix C to 36 CFR Part 327, Shoreline Use Permit Conditions: Dock and Mooring floatation Standards, specified standards currently in place. The coatings must be warranted by the manufacturer not to crack, peel, slough or deteriorate from ultra-violet rays and to retain its performance properties against wake and ice for at least eight years.

Water absorption tests developed by the American Society for Testing Materials (ASTM) does not specifically apply to floatation devices. The Corp of Engineers implements a majority of the standards followed by manufacturers and distributors. Frederic Hunt, a marina consultant, developed a simple test to determine water absorption of foam floatation docks. The Hunt Absorption Test is administered to obtain a preliminary indication of the relative absorption of foams. No governing body including the Corps of Engineers references this test as a standardized and reliable test. It is most widely used as an advertising and marketing tool.

Advancements in processing helped polyethylene coated expanded polystyrene gain wide acceptance. It is now the dominant floatation device due to its long life and durability. EPS billets are able to support 55 lbs per cubic feet, as compared to wood, which is approximately 20 to 40 times heavier, but can only support about 18 to 28 lbs. The polyethylene should be a minimal thickness of 0.125. For areas affected by ice, thicknesses should increase to at least 0.187 inch. The tubs have an estimated life span of over 40 years and even if the coating cracks or are punctured, it will remain buoyant for approximately 15 to 20 years. Corps of Engineers concluded that encapsulated floatation devices would last three to four times longer than exposed EPS.