WASTEWATER

The Ring Stiffness Rating (SN) of the pipe is dictated by the native soil, the cover height, the water table and the loading. Alternatives to PE are only manufactured in a couple of strengths, but the unique nature of the spiral wound product means that pipe can be designed for the exact ring stiffness required for each pipeline, each section of that pipeline or even each individual pipe. This saves money directly in the product manufacture and then in weight, freight and trench size. For those converting from concrete, Class 2 equates to SN16 and Class 4 to SN4.

INFRAPIPE can manufacture in a range of sizes from 450 to 3200mm in diameter as shown below. For these pipes the DN – the name – is the ID unlike some alternatives which sound 15% bigger than they actually are.  The table below shows the cross-sectional area of the pipe – and its equivalent in smaller pipes (shown by their ID). For use where burial is required, the cross-sectional area with 25% burial is also shown. Weight and OD are shown for the typical sizes for light duty and heavy duty applications; the OD is used for trench dimension calculations.

INFRAPIPE has an effective length of 5800mm (pipe length 6000mm).

Shorter lengths can be produced which means there is no waste and the asset owner is not charged for a length of pipe which then has to be cut, and the offcut disposed of. Pipes can be joined in factory for a delivered length of 11.8m or longer.

Whilst joins are normally located at full pipe lengths (effective length is 5800mm) the presence of bends and structures can require them to be located at shorter lengths; INFRAPIPE will calculate this.

There are two types of joins used for INFRAPIPE; Double Rubber Ring Joint (RRJ) is the standard join which is conducted by contractor staff onsite. Each join takes approximately ten-twenty minutes in good conditions (dependant on pipe size).

Easily with a FITTING like this:

The KRAH Technology can also create solid wall pipe which can be much more economical than traditional inline extrusion (which has large setup costs) for shorter runs of larger diameters, or more extreme wall thicknesses. Whilst the table below shows the most common SDRs (Standard Dimension Ratios – which dictate the wall thickness for a given pressure rating), INFRAPIPE can achieve any SDR.

There is no tooling setup or curing time for INFRAPIPE – pipe can be made and used immediately. When Nelson main water supply was washed away in Sep 22, INFRAPIPE despatched a truck load of replacement three days later.

Spiral HDPE is the pipe of choice in the earthquake prone Philippines for supplying the hundreds of hydro electric schemes as it can be quickly and easily repaired after a seismic event. The pipe itself Is not damaged by the earthquake, but then the hill side falls away afterwards!

INFRAPIPE will advise on the specific trench design and cover height when supplied with Geotech and water table data, to minimize installation cost. The general details of trench and cover requirements are below, and available in This Handling & Installation Guide.

This section is about the minimum cover, embedment zone geometry and requirements and is written in accordance with Section 4 of AS/NZS 2566.2.

For the minimum embedment spacing between parallel pipelines refer to table 5.1 from AS/ NZS2566.2:2002 (below):

This section is about the materials used for embedment and compaction rates required to be used during installation and is written in accordance with Section 5 of AS/NZS 2566.2:2002. The trench drawing below is to be used to reference pipe zones E1, E2, E3 & E4.

It is important to identify if there is a possibility of migration of fines between the native soil and the embedment zone material, a geotextile filter fabric should be considered, as long as it complies with Appendix J of AS/NZS2566.2:2002. The geotextile filter fabric shall be a non-woven fabric made from filaments of synthetic fibres, which meets the requirements specified in Table J1.

Table J1: Specification for Geotextile Filter Fabric

Native soils, particularly cohesionless soils with gradings no finer than those specified in Table G1, may be suitable where approved by the engineer and/or the manufacturer. It is important to avoid sands that are prone to ‘bulk’ when moist. Where they are used, ensure that the required density will be achieved.

Table G1: Cohesionless Native Soils Acceptable for Embedment Material

Imported cohesionless embedment material with gradings specified in Table G2 and Table G3 will facilitate the achievement of the soil moduli given in Section 3 of AS/NZS 2566.1:1998: Buried flexible pipelines – Structural design.

Note: Compaction equipment will be required for all embedment materials except for coarse aggregates.

Table G2: Processes aggregates acceptable for embedment materials

Table G3: Other materials acceptable for embedment materials

Table G4 should be used where gravel/sand gradings meeting the requirements of Table H1 for cement-stabilized embedment material are required (the gravel gradings in Table G2 and Table G3 do not meet the criteria).

Table G4: Embedment material suitable for cement stabilisation