Floor Specifications Required For Air Skate Load Moving Systems

Flatness

The finished top surface will be a true plane within 6mm in 3 metres, as determined by a 3-metre straight edge placed anywhere on the slab in any direction.

Levelness

The finished top surface will be level within +/- 3mm in 3 metres throughout, but not to exceed the customer's general floor levelness specifications in the event the latter is a higher specification. When operating at higher pressures this figure is reduced to +/- 2mm.

Surface Texture

The finished top surface will be non-porous and free of cracks, ships, gouges, vertical projections and step changes in plane.

Finish

The finished top surface should be paper smooth and impervious to compressed air.

Expansion and Construction Joints

Upon final cure of the concrete (23 days), all joints should be filled (after proper preparation) with a sealant having a 70 Shore 'A' hardness. When the sealant material has fully cured, it should be ground smooth using a hand-held rotary flexible-backed slow speed sander equipped with a 36-grit sanding disc.

A suitable product would be Flexane 80 by Devcon (www.itw-devcon.co.uk).

Sealing

After an initial curing period of 6-8 days new floors should have applied an application of a suitable concrete sealer. The purpose of this procedure is to ensure a deep penetration of the sealer into the concrete.

For existing floors the sealer must be applied in accordance with surface cleaning and application instructions of the sealer manufacturer.

A suitable product would be Epoxy Concrete Sealer 12560 by Devcon (www.itw-devcon.co.uk).

Protection

The surface should be protected at all times during installation to avoid damage to the surface from any cause. The air film pathways should not be traversed by equipment, but will fenced off until system installation is complete and accepted.

Repairs

Any minor damage to the concrete surface will be repaired prior to installation and operation of the air film equipment.

Chips and gouges in the surface will be further cut out to a minimum depth of 6mm or until firm, clean concrete is exposed. When cutting out an attempt should be made to create vertical edges to avoid weak feather-edging of the filler material. When the damaged area has been cut thoroughly clean the area using vacuum and high pressure air jet.

Damaged areas should be filled with an epoxy mortar having a mixing ratio of 1:5 epoxy to dry silicon sand. Overfill the damaged area and when thoroughly cured, sand flush to the surrounding surface. When the sealant material has finally cured it should be ground smooth, using a hand-held rotary flexible-backed slow speed sander equipped with a  36-grit sanding disc.

A suitable product is Epoxy Filler Patch 13120 by Devcon (www.itw-devcon.co.uk).

Construction Joints

Once the concrete floor has been laid it is essential that the standard is maintained over the entire air film operating area. Therefore it is essential prepare construction joints correctly.

If contraction joints are required, it is necessary that the slab joint is square and level with the adjoining slab. In order to avoid using excessive joint material a tightly fitted filler board should be inserted in the joint allowing 20mm for the filler material.

Control joints must not be wet-formed as square and level edges cannot be produced. These joints should be saw cut within 24 hours of laying the concrete and again a filler material used allowing 20mm of joint filling material. It is important that the filler material be compressed into the joint otherwise there could be movement of this material under air bearing pressure.

Materials suitable for contraction and control joints are the type that can be poured or injected into the joints leaving an overfill that can be ground or cut off leaving a continuous smooth surface. These materials are usually epoxy based and have a hardness of 70 Shore grade 'A'.

To fill cracks ensure that the concrete is fully cured and then blow the crack free of debris by using a high pressure air jet. Add dry sand to a mixed 2-part epoxy which can then be poured or trowelled into the crack. Once the epoxy has fully cured excess material can be sanded off.

A suitable material for this is Flexane 80 by Devon (www.itw-devcon.co.uk).

If you require further information or assistance on floor surfaces, please contact us.

Be sure to talk to your Rotair Systems contact for full details of these and other load moving systems.