Which material is NOT acceptable for use in guardrails of a guardrail system?

The material identified as not acceptable for guardrails in a guardrail system is often one that lacks the necessary strength or structural integrity required for safety purposes. In this instance, "Rooe" appears to be a typographical error, possibly intended to reference a material that is unsuitable for construction applications, such as certain types of recycled or low-durability plastics.

Acceptable guardrail materials are typically those that meet specific strength and safety standards. Steel provides excellent strength and durability, making it a reliable choice for guardrails that need to withstand significant impact forces. Wood can also be used, provided it is treated appropriately to resist decay and is designed for structural support. On the other hand, plastic may be acceptable in certain applications, especially when designed specifically for that use, but it usually does not perform as robustly as wood or steel in terms of impact resistance.

Using materials that do not meet safety standards for guardrails can compromise the effectiveness of the system, increasing the risk of accidents and injuries. Thus, understanding the properties and limitations of different materials is essential in ensuring the safety of guardrail installations.