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 classes for the purpose of assessing the measures required to protect buildings from disproportionate collapse.

SER have refined this methodology 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.

The requirements for checking of the design, the options that may be used for certification and the elements which may be included on Schedule 1 are dependent on the Risk Group and are shown in the matrix, as are the risk classes used when assessing the requirements for disproportionate collapse. Guidance Note 11 gives guidelines for checking the structural design of buildings and the relevance of Risk Groups.

It should be noted the Risk Groups of the buildings being certified will be one of the factors considered when assessing the frequency and timing of audits.

The Risk Group is a key piece of information that will be required to be input when generating the certificate of design. 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 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.

Building Risk Group Matrix

Please see the document above for the full Building Risk Group Matrix.

July 2018

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