StormPRO® Polypropylene Pipe 750mm

Installation

General

Vinidex StormPRO® and SewerPRO® pipes are twin-wall, corrugated polypropylene pipes for non-pressure applications, and can be installed in non-trafficable and trafficable areas, including under road pavements. This guide is intended to provide general information for the safe installation of Vinidex StormPRO® pipes. For more detailed information refer to AS/NZS 2566.2 ‘Buried flexible pipelines: Part 2, Installation’. When designed and installed correctly, Vinidex StormPRO® systems will provide continuous service in excess of 50 years.

 

Flexible pipes

Vinidex StormPRO® are flexible pipes. This means that as vertical loads are applied, the pipe will deflect and take advantage of horizontal soil pressure to provide additional support. After initial compaction and settlement, applied vertical loads have very little effect on deflection.
Rigid pipes, such as steel reinforced concrete pipes do not deflect,  and are designed to carry all applied vertical loads caused by soil and traffic. The surrounding soil provides little or no horizontal support to a rigid pipe. Notwithstanding this, proper placement and compaction of bedding material around rigid pipes is critical in minimising the load on the pipe.
Flexible pipes have some ability to deform without structural damage and provide designers and installers with a wide range of advantages. The structural action and design methodology of flexible pipes is well understood. Their use in all buried applications and particularly under road pavements is well established throughout the world and in Australia. As flexible pipes transfer load through deflection, loading outside design parameters leads mostly to deformation without structural damage. Overloading results in cracking of rigid pipes. Flexible pipes provide a substantial insurance for operational conditions outside design parameters.

 

Handling & storage

Being manufactured from tough polypropylene, StormPRO® pipes are robust and are suitable for use in most site conditions. The pipes are relatively light weight and can generally be manhandled. Care should always be taken when pipes are loaded, unloaded, stacked or distributed on sites. When pipes are lifted mechanically, web or rope slings should be used. Pipes should not be allowed to overhang by more than 1 metre. Transport should not have sharp projections which could cause damage to pipes. Pipes should not be dragged along the ground as this can damage the pipe, causing difficulty with jointing and testing. StormPRO® pipes should be stacked on flat firm ground, which has been cleared of debris. Pipes should be laid flat on transverse bearers at least 75mm wide at maximum 1.5m centres.
Pipe sockets should be supported so that the ends are free from loading, with sockets in each layer opposite to the previous layer. Different sizes are best stacked separately. If this is not practical, then stack with the largest pipes at the base. Framed crates must be stored timber on timber and may go up three crates but should not exceed 3m in height. If pipes are to be nested for long periods, stacks should not exceed 2m in height. Rubber rings should be stored away from direct sunlight or weathering. Rubber rings should never be placed on the ends of pipes which are being stored.

 

Trench dimensions

Preparation

The trench should not be excavated too far in advance of pipe laying and should be backfilled as soon as possible

Minimum Trench Width

The trench width should be as narrow as is practicable, but wide enough to allow adequate compaction of the haunch zone

Pipes in Parallel

Where pipes are laid in parallel, the minimum spacings between pipelines are given in Table below.

Nominal Diameter (mm)	150	225	300	375	450	525	600	750	900
Minimum Spacing (mm)	150	150	200	200	300	300	300	300	350

The trench should be excavated deep enough to allow for the specified grade, the required depth of underlay and the minimum cover.

 

Minimum Cover Height

Loading Condition	Minimum Cover (m)
Not subject to vehicular loading	0.3
Land zoned for agricultural use	0.6
Subject to vehicular loading-
(a) no carriageway	0.45
(b) sealed carriageways	0.6
(c) unsealed carriageways	0.75
Pipelines in embankments or subject to construction equipment loads	0.75

 

Jointing

StormPRO™ pipes have a simple and effective rubber ring joint system which is easy to assemble, leaktight and protects against tree root intrusion. The rubber ring is located on the spigot in the last trough between the corrugations. The below image shows the joint in cross section. For sizes DN150 to DN600, the pipe can be cut to length as required anywhere along the barrel and the same jointing system used. For pipe sizes DN750 and DN900, couplings are available for cut pipe.

 

 

The following procedure is recommended when joining StormPRO® rubber ring jointed pipes:

 

 

Cutting of pipes

StormPRO®  pipes may be cut anywhere along their length as required. The cut should be made in the valley between the corrugations at right angles to the axis of the pipe using a suitable saw. A chamfer is not required.

 

Selection of embedment material

Embedment material for StormPRO® pipes should preferably be granular, free-flowing material. This type of embedment material requires less compactive effort to provide support for the pipe and minimise soil settlement. The most common embedment material is 5-7mm crushed rock. A typical grading is shown in Table below.

Typical 5-7mm crushed rock grading

Sieve Size (mm)	9.5	6.7	4.75	2.36	1.18
% Passing by Mass	100	85-100	30-85	0-30	0-5

 

Where sand is more readily available, a typical sand grading is shown in Table below

Sieve Size (mm)	4.75	2.36	1.18	0.6	0.3	0.15	0.075
% Passing by Mass	100	90-100	85-100	70-100	50-100	0-40	0-5

For further information, refer to AS/NZS  2566.2.

 

Placing & compacting embedment material

The bedding material should be placed and graded to invert level, and compacted as required. In conditions where the trench bottom is wet, soft or irregular, it may be necessary to first stabilise, fill and level, and compact the base. Place and compact material in the pipe bedding zone to minimum depth of 75mm beneath the pipe. In order to ensure uniform support along the pipe barrel, a small indentation should be excavated in the pipe bedding zone to
accommodate the pipe sockets. The pipe side support material should be placed evenly on both sides of the pipeline
and compacted such that relative compaction is consistent with design. Side support material should be worked under the sides of the pipe to minimise voids and provide maximum pipe haunching, taking care to minimise distortion of the pipe and maintain alignment and grade. The pipe overlay material should be levelled and compacted in layers, to a minimum height of 150mm above the crown of the pipe, or as specified.

 

Backfilling

Backfill should be placed on the pipe overlay and compacted as specified but generally not in layers in excess of 300mm. Complete the backfilling operation to finished surface level.