A simple and effective system designed to prevent people, tools, materials from falling into the opening of UNCOVERED manhole.

The use is practical and intuitive, the equipment consists of a light but sturdy cross folding frame in Stainless Steel with 4 arms that is placed on the manholes opening, no matter if square or round shaped, the 4 sliding studs will be adjusted on top of the apertures in the correct position to prevent side movements, then above the cross is placed a self-centring and folding metal grille that prevents falls but allows passage of air and light, the grille can also be moved in a convenient position if there is a ladder.
In the event of sudden emergency escape of the operator from inside the manhole all group can be quickly removed with a light push up. AC90 improves safety and it is a must in today modern equipped crews as integration to the prescribed isolation barriers and road works warning signs..