Material Cost Calculator
The BPDA Calculator App is now available on your App Store.
This calculator App has been developed to optimise the structural design and material cost of your underground sewer pipeline system.
About Bedding ClassesThe load bearing capacity of an installed pipeline relates directly to the construction of the bedding which is intended to level out any irregularities in the formation, and provide uniform support around and along the length of the pipe barrel. The strength of an installed pipeline depends on a combination of the strength of pipe and the class of bedding. The selection of the bedding class is influenced by many factors, which include the nature of the ground, the loads acting on the pipeline in the trench, the strength of the pipe, and the local cost and availability of the bedding material.
Click on illustrations to enlarge
In situations where imported granular material is expensive and where supervision of site work cannot be guaranteed, it is preferable to specify a lower class of bedding with a higher pipe strength. This is the main reason why material costs for installing concrete and plastic pipes are different. Class B is based on 180⁰ granular bedding with selected backfill material; Class S requires full 360⁰ granular bedding and therefore costs more (additional costs of bedding material with more Aggregates Levy paid per metre run of pipe laid, costs of excavated material transported from site, etc.)
The cost breakdown is calculated per metre run of pipe. To use the calculator you will need the following information:
- Nominal diameter (DN) of the pipe
- Cost of pipe (per metre run) – including gaskets, connectors etc. If not integral to pipe.
- Cost of transporting excavated material from site and disposal cost to landfill (per tonne).
- Unit cost of bedding used (per tonne).
- Bulk density of excavated material and imported granular bedding (tonnes per cubic metre), if known. Default values of 2.0 for excavated material and 2.2 for bedding are assumed.
|Input||Class S||Class B||Class F||Class N||Class S|
|Pipe Diameter (mm)||225||225||225||225|
|Cost of Pipe (£/m)|
|Cost of material taken off site to landfill (£/T)|
|Bulk Density Excavated Material (T/m3)||2.0||2.0||2.0||2.0|
|Unit cost of bedding
|Bulk Density Imported Bedding (T/m3)||2.2||2.2||2.2||2.2|
The nominal diameter of a pipe is generally determined by its internal diameter. The calculator compares the nominal diameter of a concrete pipe with the equivalent nominal diameter of a plastic pipe. Where the equivalent nominal diameter of a plastic pipe is not the same numeric value as the concrete pipe, the calculator will up-size the plastic pipe to the next available nominal diameter, thus ensuring that the hydraulic design is not compromised.
The figure used for outside diameter (OD) is based on the mathematical mean for a range of different pipe manufacturers standard products. For concrete pipes, the range is based on BPDA member companies. For plastic pipes, the mathematical mean includes both solid wall and structured wall pipes.
Trench width is based on the medium trench widths as per TRRL Simplified Tables.
Bespoke products fabricated to other sizes may be available on request, but have not been included in the calculator. Contact BPDA member companies for details.