scope:

This standard is part of a suite of standards and provides the physical technical requirements for telecommunications equipment systems and assemblies intended for installation in network equipment buildings, equipment areas within buildings, electronic equipment enclosures (such as controlled environmental vaults) outside electronic equipment cabinets, and customer locations. More specifically, this standard addresses material and finish specification that are affected by ecoenvironmental legislation, specifically the European Union RoHS Directive (2002/95/EC). [1]

End-point specifications for inorganic coatings are provided for steel and aluminum used for mechanical purposes. Electronic components are outside the scope of this standard, although acceptable finish substitutes for lead solder (when used as a corrosion protection) is addressed. The scope does not include organic coatings such as paints or oils.

This standard also provides wording to supplement drawings with workmanship requirements. The classifications provided may be used to specify cosmetic quality requirements on most finished surfaces.

Purpose

Hexavalent Chromium (CrVI) has been the standard for plating of aluminum and steel sheet metal, fastening hardware and board-level mechanical components since cadmium and gold platings were phased out in the 1970s and 80s. "Yellow chromate" has been the mark of a high quality plating in the telecommunications industry for 20 years. It has been used for unpainted materials and as paint base for liquid or powder coatings. The use of CrVI is being limited by Restriction of Hazardous Substance legislation (aka RoHS directives.) [1,2]

Not all substitute platings available in the market will have a comparable performance necessary for finishes on telecom equipment. Given this, it is important for the US telecommunications industry to agree to the product changes required to satisfy legislative requirements, while assuring the quality and reliability required for network infrastructure equipment. The purpose of this standard is to provide technical guidance for the specification, design and construction of mechanical hardware, cable assemblies, and printed wiring boards. Finish choices and specification language are provided.

Application

The application of this standard are those pieces of equipment that need to be free of hexavalent chromium, cadmium, and lead beyond the legislated threshold level or those in the Joint Industry Guide, which ever is lower. The intention is to augment ATIS-0600006.2006, Mechanical and Structural Standard's [2] section on finishes. A set of metal finishes that are acceptable for given use conditions is provided. Since a mix of structural metals is used in most telecom products, this standard seeks to provide the means to match color of finishes for aesthetic appeal. Visual parameters for judging acceptance or non-acceptance of inorganic finished parts are also provided to compliment the aesthetic requirements.

Films may be determined to be free of CrVI by using either EN 15205, DIN 50993-1, or equivalent method.

Performance requirements for finishes on ferrous materials are written around the performance of trivalent chromium (CrIII) finishes. These are believed to be the only chemistry that will meet the performance criteria on ferrous materials. This standard is not intended to exclude a novel formulation that will meet end-point requirements. In the case of aluminum substrates, CrIII-based formulations are assumed to have the best performance, although it is known that some non-chromium formulations will meet performance specification and hence are permitted. The end-point specifications provided herein will be suitable for a wide range of telecom applications. This does not obviate testing and verification of design, or the need to specify different corrosion or electrical resistance values should an application require it.

This standard is not intended to apply to preplated steels¹, stainless steel, metal-filled polymers/resins, or metalized plastics.

¹ One comment is worth making about pre-plated steel from a RoHS perspective is though zinc-pre-plated material is intrinsically RoHS-compliant, it is sometimes supplied with a chromate finish. When specifying pre-plated material, it is recommended that RoHS requirements be clearly stated.