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Tank Extensions

Phoenix Precast offers a wide array of products to aid during the maintenance and inspections of septic tanks, distribution boxes and leaching chambers. We also provide items for light duty applications or products that require HS-20 traffic loading requirements.

Light Duty Requirements

For light duty requirements, we recommend access be kept between 6” & 12” below grade to meet NHDES requirements along with protecting the liability of the site contractor. Any access to grade would include a cast iron frame & cover which ensures that the weight of the cover would prevent unauthorized entrance per NHDES 1010.05.e.

Access to grade for precast products that necessitate a hatch for access are available in either round, square or rectangular products and are available with different loading capacities.

Extensions To Grade (Light Duty)

24in Diameter Tank Extension LDPDF
24in Heavy Duty CoverPDF
24in Solid CoverPDF
24in Standard Tank CoverPDF
36in Diameter Tank Extension LDPDF
36in Tank CoverPDF
Tank Extension AssemblyPDF

Extensions To Grade (HS-20 Loading)

24in Diameter HS-20 Adjustment RingsPDF
36in Diameter HS-20 Adjustment RingsPDF

Extensions To Grade Boxes (With Hatches)

Light Duty Hatch With RiserPDF
HS-20 Rated Hatch With RiserPDF

Extensions To Grade Manholes (With Hatches)

4ft Diameter Structure Hatch SelectionPDF
5ft Diameter Structure Hatch SelectionPDF
6ft Diameter Structure Hatch SelectionPDF

Extensions To Grade Manholes (With Frames & Covers)

4ft Diameter Access To GradePDF
5ft Diameter Access To GradePDF
6ft Diameter Access To GradePDF


77 Regional Drive, Concord, NH 03301        P: (800) 639-2199        F: (603) 224-2927        This email address is being protected from spambots. You need JavaScript enabled to view it.

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