2

2.0 SPECIFICATIONS

Recommended Specification Clauses

General

"All access covers and grates shall be manufactured by

Havestock or an approved equal alternative which has a licence for the StandardsMark (AS3996) and

a fully accredited Quality Assurance Programme conforming with AS/NZS ISO9002."

Rating

Castings shall be of adequate design for the specified load rating conforming with AS3996 Classes A, B, C, D, E, F & G.

Design

Castings shall be cast clean and free from sand inclusions, blow holes, shrinkage, cracks and cold shut. Castings shall be neatly finished and fit together properly.

Markings

Conforming with AS3996, products shall include :

Name of manufacturer
Product Class

Product Type

QA Serial Number

QA Pass of Inspection

Familiarisation

Access covers & grates consist of :

The cover or grate which removes from the frame to allow access.
The frame which is fixed to the ground.
The cover and frame are cast with matching forward and reverse tapers so the cover locks into position and forms a gas tight seal.

Castings

Made from AS1830 Grey Cast Iron or AS1831 Ductile Iron.
All covers & frames have been cleanly cast and are free of voids, air & sand holes, cold shut and chill.
Castings are neatly dressed.

Strength (Covers)

Covers are ribbed to provide maximum strength for a given weight of metal.
All frames other than Class A & B, are cellular cast for maximum strength and no movement.

Anti-Rocking

All mating surfaces are fully machined to totally eliminate rocking of the cover/grate in the frame.
All frame joints are lead packed to create a complete seal and improve overall strength.

Gas, Water & Air Tight (Covers)

All mating surfaces are fully machined to assure gas, water and air tightness.
Watertight to water head of 150mm for 10 minutes.
Gastight to a pressure of 10 kPa for 3 minutes.

Hydraulic Efficiency (Grates)

The bar design of the grate carries traffic loads across the opening and efficiently disposes of surface water at 76.5 litres per second per square metre of clear opening. For further details please see Section 18 Technical Information.

Ease of Use

Non-rotating keyholes.
Plastic plugs fitted to all covers to prevent key holes accumulating foreign matter.
Virtually all covers can be removed/replaced by one person using any standard access cover lifting key.

Appearance

All cast iron products are bitumen dipped or paint sealed to protect the cast iron finish as well as maintain the aesthetics of it's environment.
Cover ribs, grate bars and frame edges are cast straight and well finished to form a pleasing pattern when installed and filled with concrete.

Inspection Openings (Covers)

Any cover from our range can by modified to include a small circular insert (100 or 150mm).
This type of product is mostly used in situations that require frequent inspection but not necessarily full access. (ie fuel tank installations).

Brass or Stainless Steel Edged Finishes

All Havestock covers (except circular) can be supplied with either brass or stainless steel edges to further enhance the finished product.

Brass edges allow the access cover to be filled with decorative flooring materials such as Terrazzo, tiles and split pavers. In these applications only the brass edges and brass key hole covers are visible.

When ordering these types of covers please quote the type of flooring material to be used. Our technical sales staff can then advise you of the correct height of brass the cover will require.

Specifications

Code Edging Height

A66A BE 12 = 600x600mm Class A Brass Edged 12mm cover and frame

Further information on these decorative edged access covers is available in Section 4 of this catalogue.

Installation Guide

Brass edged units are supplied with closed level frames and an installation bolt which is fitted to ensure the unit is secure for transportation and is installed correctly on site.

1. Install the cover and frame so that the top edge of the brass edge is at the same height as the finished flooring.

2. Concrete or grout the cover and frame into position and allow the compound to cure. Do not fill the lid at this stage.

3. Once the compound has cured remove the installation bolt and then fill the cover.

4. The cover may now be removed when necessary. When replaced into the frame, the complete unit will be gas-tight.

Remember :

Installation bolts must be removed before filling the cover or else you will not be able to remove the cover.
Covers must not be removed from the frame prior to installation.
The units must be treated with respect on site.

1. Do not mix covers and frames.

2. Do not leave the brass edges exposed before finishing the flooring - pack around the brass to protect them from excavators
& heavy tools.

Once installed into position, all surfaces should be cleaned and heavy grease applied to the mating surfaces before returning the covers to their original position.

Bolt Down Covers

In some cases, access covers are required to have either security or back pressure retaining facilities. Havestock make their total range of access covers available with this facility.

(A) Security

As required for applications such as roof water in most shires, Havestock supply access covers which are bolted down to prevent lifting of the cover by children or by overflow of roof water. In these cases, little or no "head" is involved.

(B) Back Pressure – No Head Conditions

In some applications such as in basement car parks or inside shopping centres, the access covers are bolted down in such a way as to stop any over-flow of stormwater or sewer as a result of blockages. In these cases little or no "head" is involved.

(C) Back Pressure - Head Conditions

Where "head" conditions are to be experienced, special conditions must be met in terms of bolting down the access cover :-

1. Frames for access covers must be drilled or knocked out so that floor area reinforcing bar is extended through the frame.
This reinforcing then stops the back pressure or "head" lifting the total unit out of the concrete.

2. Access covers and frames are specifically modified to accept 10mm diameter stainless steel bolts, which are to be used
for retaining the cover in the frame.

3. Access covers also need to be specifically modified to ensure that concrete infill is not expelled by back pressure.

4. Maximum "head" expressed in metres must be determined at time of order placement.

5. Maximum "head" must be limited to 5 metres with the normal or ideal being 3 metres.

6. Heads in excess of 5 metres should not be retained by access covers.

Surface Treatment System

Machined (i.e. gastight) Havestock covers and frames can be coated in a new Surface Treatment System to provide an effective gas and water tight seal which virtually eliminates rusting or deterioration of the machined surfaces.

The HS-1 Surface Treatment System is available as an option and must be specified as an extra. To specify this system, add HS-1 to the Product Code.

A66A ~ standard machined finish

A66A HS-1 ~ machined surfaces coated in HS-1 Surface Treatment System

Testing

The HS-1 Surface Treatment System has been control tested in extreme
environmental conditions for a period of nine months.

No rust or deterioration of the machined surfaces occurred.

Sections of the cover which were not coated in HS-1 were serverely rusted.

A full environmental test report is available for approved applicants from the Havestock
Quality Manager.

The Need for a New System

Over many years, the industry has used grease to provide a gastight seal between machined surfaces of covers & frames and obviously grease needs to be replaced on a regular basis to ensure this gastight seal.

Non-gastight covers do not receive regular maintenance and re-greaseing is not carried out. Traditionally this has caused rusting and growing together of the mating surfaces with the resultant difficulties in lifting covers after years of installation.

HS-1 Surface Treatment System

The trials conducted have been designed to prove that by using particular product on machined surfaces we have been able to overcome the problems of :

rusting,

growing together of surfaces under wet conditions

providing an effective seal between the machined surfaces.

These machined surfaces are both watertight & gastight (as detailed in AS3996) without the need to coat the surfaces with grease.

Obviously these tests also needed to report on the product’s abrasion resistance, suitability to harsh environments ( PH between 6 & 9.5) and longevity of the Surface Treatment in use.

Results

On recovery, the units were washed down and again inspected with the following results recorded.

Bitumen coating as central rust proofing of body of cover and frame has been completely dissolved and bare cast iron was severely rusted.

Machined surfaces were still completely coated with the Surface Treatment System and no rust was visible.

Areas of Surface Treatment were subsequently removed and the machined surface exposed. This surface showed no evidence of rust or deterioration and returned to it’s original machined surface finish.

Machined surfaces under the Surface Treatment System have shown no evidence of exposure to the elements, rust or deterioration.

Maintenance of Surface Treatment

It has been observed during the testing program that wiping the surfaces with a clean damp cloth is all that is necessary prior to refitting of the cover to the frame. Any surface defects due to stones or excessive handling can be effectively repaired by applying top coat to the effected area.

The Surface Treatment System can also be retro applied to existing covers and frames by cleaning surfaces with a wire brush and/or emery paper (or by sandblasting) and then applying the Havetec HS-1 system.

Again from factory testing, it has been found that the surfaces do not delaminate or break-down with loads of up to 210kN applied to units after one and a half hours of drying time.

This suggests that retro application to units in the field is possible without a lengthy cycle time for curing of surface treatment and that this product could effectively be used in the field for eliminating "talk of chatter" of covers when subject to loads.

Conclusion

The Havetec Surface Treatment System appears to overcome most of the problems associated with machined covers and frames with respect to sealing and removing of covers in operation.

The Surface Treatment is capable of being retro applied and repaired in service. The system is also beneficial when applied to non-sealed covers for the elimination of rocking and noise when subjected to traffic conditions.

back