This document outlines the key requirements for cable tray layout, installation, and fireproofing in industrial and commercial environments. Route Planning and Layout PrinciplesPropane hose connects a weed or roofing torch to the POL valve on a propane tank. Has a built in excess-flow valve to shut off gas flow if it exceeds 500,000 Btu per hour. The selection of material and finish is a function of the environment in wh tant in a wide range. Fire resistance is a key factor when selecting cable trays for areas where fire hazards are present. Electrical fires can spread rapidly through the cables within a tray system, which is why choosing the right material for your cable tray is paramount in reducing the risk.