While fire safety professionals have found difficulty interpreting PAS 9980, as our previous article discussed, we have – as the standard's authors – seen particular problems with the preparation of fire risk appraisals of external walls (FRAEWs).

FRAEWs are critically important to understand the risk of external fire spread on existing buildings. Such buildings will necessarily fail to comply with current Building Regulations given that they were constructed to meet the requirements of previous versions.

They may even suffer from deficiencies, whether arising from their original design and construction or due to the passage of time.

However, existing buildings should still be perfectly safe to live and work in; FRAEWs carried out in accordance with PAS 9980 by competent professionals will differentiate buildings that are safe from those that are not.

By detailing some of the common mistakes we have encountered with appraisals, therefore, we can help ensure greater rigour when it comes to fire safety.

Being clear on assessment and assumption
Some FRAEW reports include assessments that assume proper construction of fire protection in external walls where there has been no inspection.

Certain forms of external wall construction, as set out in PAS 9980, are inherently resilient to external fire spread and tolerant to construction defects, so their fire performance is unlikely to require an FRAEW.

However, in most cases FRAEWs are necessary for wall constructions that rely in some way on detailed aspects of construction.

External visual inspection is often not adequate to confirm the kind of wall construction; for example, rendered expanded polystyrene looks very similar to rendered blockwork, while brick slip closely resembles full brick.

It is therefore essential that these FRAEWs are supported by some form of intrusive inspection, even if only to confirm that the design information for the building is accurate.

Inspections do not need to have been conducted personally by FRAEW authors themselves; inspections by other appropriately competent persons could be relied on, provided the findings have been adequately recorded and communicated.

Nevertheless, some FRAEW reports are based on limited access to documentation.

There have been instances where appraisals are required, but where permission has not been granted for the appraiser to consider the building's current fire risk assessment because of concerns about the assessor's professional indemnity insurance; policies for fire risk assessors have been found to carry strict exclusions when it comes to external walls.

In such cases, the appraiser might have to make assumptions about the adequacy of provisions in the building, for example assuming that the compartmentation is adequate.

Such assumptions are acceptable, but must be clearly set out in the FRAEW report.

The report should also detail whether any assumptions are particularly significant in terms of risk outcome; that is, could a tolerable risk become intolerable in the event an assumption proves to be false?

Those factors should be clearly identified in the executive summary as well.

Where responsible persons are or become aware of these sorts of limitation about the work of any of professionals on their behalf, it is incumbent on them to coordinate the information they hold so that preventative and protective measures are properly implemented on the basis of facts, not just assumptions.
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