Standards Development

Scope

BS 1139-6 specifies requirements for the structural design of prefabricated tower scaffolds utilizing components from mobile access and working towers specified in BS EN 1004 but in configurations that are outside of the scope of that standard.

These configurations include:

a) prefabricated tower scaffolds outside the height limits of BS EN 1004;

b) towers with more than one working platform;

c) large deck tower scaffolds;

d) linked tower scaffolds;

e) cantilever tower scaffolds;

f) stepped tower scaffolds;

g) tower scaffolds used as a means of access;

h) towers built on base plates instead of castors.

This British Standard applies to prefabricated tower scaffolds subject to wind loads up to and including 0.1 kN/m2. It does not cover prefabricated tower scaffolds using guys as a method of stabilization.

Purpose

BS 1139-6 provides the criteria for prefabricated tower scaffolds using components from BS EN 1004 mobile access towers but in configurations which are outside the scope of that standard. When BS 1139-6 was revised in 2014 it took into account planned changes to BS EN 1004 which are now finalised and about to be completed. It also considered the state of the art in the industry at that time. The revision was the result of a demand from the industry to provide a more structured design framework to improve these types of temporary works equipment. HSE took an active interest to improve standardisation in this area to meet the requirements of the Work at Height Regulations. The standard was revised into a more detailed engineering design standard, providing a way for manufacturers to develop a wider range of safer designs.

EN 1004 is now due for publication in 2020. There have been further changes to that standard which need to be considered in BS 1139-6. For example, BS EN 1004 now covers products from ground level, rather than from 2.5 m. The later revisions of other reference standards such as BS 1139-2-2 Metal scaffolding. Couplers and fittings also need to be considered.

The state of the art in industry has also moved on. Equipment manufacturers are now producing “standard configurations” from BS 1139-6 which are generally recognised configurations with full product instruction manuals. “Non-standard configurations” are also being produced, which are site and location specific. BS 1139-6:2014 makes no difference in the requirements between these two very different ways of supplying prefabricated tower scaffolds into market. Experience with the standard indicates that further detail could be added, to clarify the basic principles of when testing should be carried out and when calculation is enough. This would also aid in the certification of generally recognised configurations.

Considering, but not limited to the points above, it is recommended that BS 1139-6 should go through a full revision. The revision should include the state of the art in the industry.