NSSS – National Structural Steelwork Specification

NSSS 7th edition image

The BSCA has recently published the 7th edition of the NSSS. This latest edition has been extensively updated and represents the biggest change since its introduction in 1989. One of the main changes is the inclusion of a new section on intumescent paint systems.

The National Structural Steelwork Specification for Building Construction (NSSS) is primarily a construction (or execution) specification but also acknowledges the common contractual situations where the steelwork contractor designs the connections (and in some cases the members as well) - it includes checklists of information that the contractor needs to carry out design.

The principal topics covered in the NSSS are as follows:

  • Information required by the Steelwork Contractor
  • Materials
  • Information provided by the Steelwork Contractor
  • Workmanship
  • Welding
  • Bolting
  • Fabrication accuracy
  • Erection
  • Erection accuracy
  • Protective treatment
  • Quality management.

Following the tragic Grenfell Tower fire and the call from Dame Judith Hackitt for industry not to wait for legislation, the BCSA said it and the wider constructional steelwork community decided to take ownership of the specification, application and inspection of intumescent paint systems.

Section 10 of the NSSS now includes comprehensive information on intumescent paint systems and to improve quality, it encourages the paint systems to be applied in the workshop rather than on-site. Other significant changes include a mandatory requirement for all steelwork contractors to put in place a third-party certified welding quality management system to BS EN ISO 3834.

The main body of the NSSS is limited to Execution Class 2, but this version also contains an Annex of the requirements for Execution Class 3 for static structures and an Annex giving general guidance on Execution Class 3 for buildings subject to fatigue, such as crane supporting structures.

To allow steelwork contractors time to put in place the necessary third-party systems to comply with the Specification it has been decided that the NSSS will not come in to force until 1st January 2021.

Hard copies of the 7th edition of the NSSS, which now includes BCSA member listings, can be obtained from the BCSA Bookshop from Monday 14th September and are priced at £20 for BCSA members and £25 for non-members.