Corrosion Protection Powder Coating & Northpoint Ltd: BS 1722-16, Fences

What is BS 1722-16?

BS 1722-16 is a document first published in 1992, the latest version published by BSI and prepared by Technical Committee B/201. This particular post deals exclusively with Fences – Part 16: Specification for Powder Coatings used as a plastics finish to components and mesh. The whole of the standard is split into 18 parts.

It specifies the performance and test requirements of powder coatings applied as a finish to fence components and mesh.

Coating Powders – the powder manufacturer or supplier if different shall provide the applicator with:

1. Manufacturer name
2. Trade name
3. Colour ref.
4. Batch number

It’s important that the powders are stored in unopened containers for up to 12 months or less if specified by the manufacturer at less than 25^oc, again unless specified otherwise by the manufacturer.

Powder Properties

1. Appearance – no scratches, blisters, craters, or holes visible at a distance of around 0.5 m (it should be noted that on HDG that there will be some unevenness. Thicker coatings should be expected near surface edges. A slight degree of orange peel finish is allowable by agreement with the customer)
2. Colour – The colour should match the manufacturers specification which can be observed when compared in north facing daylight by comparison to an agreed standard
3. Thickness – this should be within an agreed range or at least thicker than an agreed minimum
4. Adhesion – no loss of adhesion on components or mesh (when cut at a 30^o angle on components and peel back attempted, or peel back 20 mm on mesh and pull)

Pre-Treatment

Pre-treatment is determined by the powder manufacturer which is normally a chemical process, or a mechanical process, or a combination of the two (mechanical should always take place before the chemical process). There are many alternative pre-treatment systems that can be used and will be compliant with the standard.

Typical Types of Pre-Treatment

1. Chemical – conversion coating applied to a rust/corrosion, grease, dust free surface and not consisting of a powdery type deposit when viewed after drying. Typical processes might be chromate conversion, phosphate conversion, silane/zirconimum based process or another suitable alternative.
2. Mechanical – sweep blast cleaning but in such a way that the HDG remains intact after the process. Blast abrasives such as carborundium of aluminium oxide are typically used at a pressure of not more than 300 kPa.

Packing and Handling

Powder coatings are generally robust but should still be handled with care so as to avoid damage and/or contamination. Its recommend that when packing coated parts that recycled materials should be used wherever possible and labels attached to each bundle of coated parts, ideally warning that care should be taken when handling. Additional care should be taken when handling coated parts in low temperatures.

Get in touch at:

Tel:     0161 330 4551 (+44 161 330 4551)

E-mail: sales@northpoint.ltd.uk

Blog Author – Philip Dawson, Technical Advisor, philip@northpoint.ltd.uk for technical and specification enquiries