Typical Construction Guidance Notes

Components within HRD Technologies supply shown in bold.

The chamber should be constructed using methods and materials suitable to the ground conditions (either precast segmental rings or manhole chamber rings) to leave a smooth finished circular shaft with a flat concrete base. A section should be left out of the chamber wall above the spillway slot to allow insertion of the stainless steel spillway assembly .

HRD Technologies will deliver the Storm King^® Overflow with Swirl-Cleanse™ components to site for installation by the main contractor. Off-loading of the components to be to a firm, level surface adjacent to the lorry.

Any on-site welding needed to complete the assembly of the components (due to transport restrictions larger units have to be delivered in sections) will normally be carried out by certified welders appointed by HRD Technologies.

The components shall be lifted either at the lifting lugs where attached (these to be ground off or removed after installation is complete); or at the slots cut in the components for attachment of shackles for the use of lifting chains or other suitable equipment; or at lifting points as specified / marked appropriately by HRD Technologies. WARNING - Failure to lift at these locations may result in deformation of the structure and HRD Technologies cannot accept any responsibility for this action.

Level and orientate the CONE BASE with the UNDERFLOW CHANNEL and OUTLET PIPE SPIGOT onto the concrete base, and fix down with suitable drilled anchor bolts. Connect the OUTLET PIPE SPIGOT to the new foul underflow outlet pipe using an appropriate coupling. The OVERSPILL PIPE must also be placed prior to concreting. This pipe must be truly vertical and its vertical centre line coincide with the true centre of the chamber. This is CRITICAL as the HYDRO SWIRL-CLEANSE™ CHAMBER must pass over it and is concentric with this pipe. Connect the OVERSPILL PIPE SPIGOT to the new outlet pipe using an appropriate coupling.

Surround the CONE BASE etc. in concrete of the grade specified and screed the bottom benching to falls about the UNDERFLOW CHANNEL . Ensure that the central OVERSPILL PIPE is temporarily supported so that its setting out position is not disturbed.

Fill the CONE BASE with concrete in layers up to a distance of not more than 100mm from its top rim to prepare for stage 8. Good engineering practice should be observed in order to bond the concrete within the CONE BASE to the CENTRE CONE .

Lower the CENTRE CONE onto the CONE BASE ensuring that the bottom rim of the CENTRE CONE is located inside the top rim of the CONE BASE and that the two parts are aligned correctly. (Due to manufacturing tolerance the 4 bolts may only align perfectly in one orientation of the components). Fix the holding down bolts (provided), then fill the CENTRE CONE with mass concrete and form a smooth surfaced dome around the central OVERSPILL PIPE .

Fix the DEFLECTOR PLATE to the shaft wall using the bolts provided. Mark levels for the LEDGER ANGLES .

Where the upper assembly is delivered in two halves HRD Technologies will site weld these together for which a level, firm surface is required. Typically at least 5 days notice is required.

Lift the complete upper assembly into the chamber connecting the ends of the SUPPORT FRAME onto either the LEDGER ANGLES or into a notch formed in the top ring of the chamber wall. If LEDGER ANGLES are supplied, the UPPER ASSEMBLY should be suspended whilst the LEDGER ANGLES are fixed.

Prior to grouting up, but after the support points are fixed, the top edge of the SWIRL-CLEANSE™ CHAMBER must be levelled to the specified value. The means of adjustment provide will depend on the size of the unit. For larger units (> 4.0 m diameter) the crane may be required for the placing of the permanent shims.

Then fix the SPILLWAY with the required number and size of anchor bolts to the chamber walls. Grout around the spillway (walls and floor) to provide a watertight seal.

The SIPHON is dropped into place to the specified level within the adjacent overflow chamber. Once positioned the side brackets are bolted to the chamber wall and then the siphon is in turn bolted to these. The DRAINDOWN PADDLE should then be placed in position. The SIPHON outlet area is then benched whilst taking care not to block the SIPHON BUCKET DRAINDOWN PIPE .

Finally, finish the top of the chamber with either a precast concrete cover slab, or steel covers. The unit can also be left open-topped where required.