Benchmark Access Covers & Survey Boxes

Berntsen's Bench Mark Access Covers (BMAC) are based on designs developed for the NGS bench mark. Access covers are usually used to provide a protective cover for sectional rod monuments (stainless steel or aluminum rods) like those used for geodetic control or GPS.

Berntsen offers a variety of models of the BMAC Bench Mark Access Covers:

•          Model BMAC-1, the latest refinement of the original concept, is designed to fit over a section of 5 inch (127mm) PVC Well Casing. Due to the exposed (raised) dual (2) hinge design, the BMAC-1 is recommended only for general use on open land. A ring of concrete is usually poured around the BMAC outer ring and PVC pipe.

•          Soon after the introduction of BMAC-1, our customers requested a more versatile access cover. one that could be used with standard 6" (152mm) Schedule 40 PVC pipe. Model BMAC-6 (fits inside 6" PVC pipe) are further refinements of the original design. Most notable changes are a much more heavy-duty design with significantly more material at critical points and a stronger and fully recessed hinge. This cover is therefore suitable for use in pavement areas such as streets or highways, as well as on open land. Like the BMAC-1, a ring of concrete is often poured around the cover's outer ring. 

We also offer the BMAC6 with a tamper-proof screw that requires a special tool to open.