BMAC1 Benchmark Access Covers
- Aluminum cover based on designs developed for the NGS bench mark
- Used to provide a protective cover for sectional rod monuments (stainless steel or aluminum rods) like those used for geodetic control or GPS
- Designed to fit over a section of 5 inch (127 mm) PVC Well Casing
- Recommended only for general use on open land due to exposed (raised) dual hinge design
- Weighs about 1.8 pounds (.8kg)
- A ring of concrete is usually poured around the outer ring of the BMAC Access Covers
* Per ASTM standards, 6" Schedule 40 PVC pipe can vary significantly in the inside diameter (up to .090") compared to the better precision of a good casting (.010"). Additionally, pipe from various suppliers can vary significantly within that range. Generally, most suppliers try to make the pipe wall as thin as the specifications will allow in order to save material.