Recessed manhole covers or recessed tray covers are utilized within some paved area in order to hide the presence of inspection chambers, manholes, and access fittings.
When it comes to the field of decorative, natural or colored stone paving, recessed manhole covers are vital, particularly when compared with utilitarian covers normally employed in modern construction. Take a look at the below photos for recessed manhole covers and recessed tray covers.
Basically, they comprise of two components: The frame fitted above the manhole and the tray, sitting inside the frame. This is filled with paving in order to fit in the surrounding location.
The normal size employed on patios and domestic driveways is 450x600x90mm, even though there are also other sizes available, normally on order. The larger covers normally use two or more different trays inside one frame so as to manageably maintain the mass of paved tray.
The ones that are employed for commercial projects or public areas basically consist of a galvanized steel frame, together with galvanized steel tray. Those for light-use like in residential driveways can use plastic frame. There are also now for use plastic trays for footways or driveways due to progress on plastic molding technology.
Only grade “A” covers required for foot traffic. However for driveways, what is required is “AA” cover together with some safe working load of at least 1.5 tones. Consider using some class B cover for driveways with vans or large 4x4s. Class B, C and/or D covers are required for heavier applications, in public places.
As has been noted, a number of the recessed manhole cover or recessed tray covers used in residential areas are now made of plastic. This comes with some advantages like lesser manufacturing costs and weight. There are also now fewer reports of trays being jammed. On the other hand, a number of contractors are not pleased that there are trays and frames which are susceptible to deformation. This in turn affects the installation, and the beauty of it when finished.
The progress to plastic frames has made it possible the designing of “Square to Round” recess tray covers. These are made to provide a rectangular or square cover fitting over a circular, or round, Access Chamber (AC), or Inspection Chamber(IC).
Recessed tray covers or recessed manhole covers are mean to make access covers and manholes less noticeable, and maintain the paving’s visual aesthetic. When professionally and correctly installed, they can be barely noticed. However, when they land in wrong hands, they become some source of dangerous weapons.
To prevent jamming, it’s advisable that the outer edges of the tray and the frame’s internal faces be coateda generously with thick, non-setting lubricant like petroleum jelly after the final fixing. Through this, the sand grains are prevented from entering the gap between the tray and frame. The jelly also makes it easier to remove the tray.