Building standards - managing fire risks associated with use of external wall systems: research

8. Conclusions

202. The Guidance Tool has a place in the Building Warrant process. The outcome of this research is that the most useful aspect will be as a formalised checklist/process for Building Warrant applicants to follow, and as an aide memoir to local authority verifiers.

203. Local authority verifiers often rely on their experience with products’ fire performance and decide on the suitability of non-standard external wall designs with limited recording of the decision making process. Advice received externally from experts/manufacturers is saved on file. It is the authors’ opinion that better record keeping is important for external wall designs as products’ fire performance is tied closely to the tested configuration, and reference material should be consulted to prevent inappropriate or untested arrangements from being approved/constructed.

204. Local authority verifiers carry out spot checks of construction quality of external wall systems on site. This is in theory satisfactory as the responsibility for construction quality sits with the “relevant person”, however as construction quality is constantly in question (in the experience of the authors) additional oversight is advisable.

205. Additional oversight could come in the form of additional site inspections by local authority verifiers or a qualified independent third party acting for the “relevant person” (such as a Clerk of Works). Such site inspections would still be subject to review by local authority verifiers. Input would be needed from the BSD/ to achieve this, including guidance for all and a suitable accreditation scheme.

206. There is no strong evidence that a separate stage for external wall systems should automatically be introduced for every project, although this is done routinely for large projects.

207. As local authority verifiers were unable to estimate the percentage of time devoted to reviewing external wall systems, quantitative analysis has not been possible.

208. To address construction quality issues, clear guidance should be given to local authority verifiers and Building Warrant applicants on how to most efficiently obtain the services of a qualified independent third party acting for the applicant to carry out suitable site inspections (suitable is explained by the Guidance Tool).

209. Where decisions are made regarding the suitability of external wall systems, local authority verifiers should be encouraged to record the decision making process to reach the conclusion, particularly where the conclusions is to accept the proposal.