Many of the decisions that a Certifier will take while undertaking the certification of the design of buildings structures are based on an assessment of the consequences of failure. BS EN 1990:2002 Eurocode - Basis of Structural Design proposes in Appendix B Table B1 three consequence classes, which are based on the consequences of failure or malfunction of the structure and gives examples of buildings in the various classes.

The Technical Handbooks use the above methodology in Section 1.2 where in Table 1.1 they assign buildings to four Risk Groups for the purpose of assessing the measures required to protect buildings from disproportionate collapse.

SER have refined this methodology for the purpose of determining the level of checking required and for determining the elements which may be included on Schedule 1 and have assigned buildings to five Risk Groups as shown in the following Building Risk Group Matrix. This matrix should be used to determine the Risk Group to which the building belongs.

Guidance Note 11 gives guidelines for checking the structural design of buildings and notes that the Certifier should determine the appropriate Design Check level for the project or part of the project.

The Risk Group is a key piece of information that will be required to be input when generating the certificate of design and will be one of the factors considered when assessing the frequency and timing of audits.

There are likely to be circumstances where the Building Risk Group taken from the matrix is difficult to determine or where it appears to be inappropriate, for example:

  1. Where the building under consideration does not obviously fall into one of the building types listed in the matrix.
  2. For a warrant application where there are multiple buildings which would fall into differing Risk Groups, the Risk Group to be selected when generating the certificate should be determined by the Certifier as that most appropriate taking account the relative sizes and importance of the buildings. If the most onerous Risk Group is NOT selected, then the Certifier must ensure that the checking regime and the Schedule 1 items for any particular building are those appropriate to the Risk Group for that particular building. For example, where the warrant application covers a development comprising a number of houses and a care home the Certifier may select RG1A or RG1B as that Risk Group is appropriate to the houses which form the major part of the development. If the care home is classed as Risk Group 2A the Certifier must ensure that the design is appropriately checked and that the only items appropriate to RG2A are included on Schedule 1.
  3. For minor alterations to buildings in Risk Group 3, which do not affect the primary structure of the building.
  4. For buildings which are structurally straightforward, such as steel portal-framed buildings used as Factory (Class 1) or Storage (Class1).

In these circumstances the Certifier may choose to follow the principles set down in BS EN 1990:2002 Eurocode - Basis of Structural Design to determine the most appropriate Risk Group.

If the decision is to accept a lower Risk Group, the reasons for deviating from the guidance in the matrix must be recorded in both the project and certification records.

Notwithstanding the above, the Risk Group to be used when assessing the measures required to protect buildings from disproportionate collapse should be determined from the Table 1.1 in the Technical Handbooks.

Building Risk Group Matrix

Please download the document above to obtain the full Building Risk Group Matrix.


January 2023

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