Study of temporary edge protection systems of highdensity polyethylene (HDPE)

Abstract

UNE-EN 13374 Temporary Edge Protection Systems Product Specification, Test Methods, classify temporary edge protection systems (TEPS) in three classes (A, B and C), depending on the inclination of the work surface and the height of fall. The standard establishes geometrical and mechanical requirements that the TEPS must overcome depending on their classification. Class A systems, which are the most widely used, can only be used when the angle of inclination of the work surface is less than 10 °. The regulations are written for wooden or metallic elements, but they do not exclude the use of any other material. Polyethylene is a thermoplastic polymer that combines physical and mechanical properties, such as a low density and a good weight-strength ratio Also, it is a material easy to process. All this makes it suitable in a wide variety of applications, making it the plastic material with the highest production in the word. Depending on the polymerization process used, different types of polyethylene are obtained, which are characterized according to their density. High density polyethylene (HDPE) usually has density values between 0.94 and 0.97g/cm3. Its longitudinal modulus of elasticity has a low value, around 2,000N/mm², and its yield strength hight values, even when loads far from its elastic limit and with short duration are applied. It happens mainly in samples that do not present important discontinuities in their surface, what could produce concentration of tensions leading to a fragile failure. The HDPE has excellent properties to be used as a component of collective protection in general and as TEPS in particular, where the actions are produced mainly in the form of impact. The TEPS of HDPE only have horizontal displacements, its enormous rigidity in the vertical plane makes the displacements in this direction practically null. This type of system offers a safety against tilting higher than that of systems manufactured with steel tube rails or wooden boards, in which a displacement would occur that would have a vertical component and a horizontal one.