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Why Hackitt was right to keep desktop studies

Nigel Morrey

Among the many areas of our industry to come under scrutiny since the tragic events at Grenfell Tower last year, perhaps one of the most contentious remains the use of desktop studies.

Desktop studies are used to establish Building Regulation compliance for cladding materials in lieu of full-scale fire testing.

In her Building a Safer Future report published last month, Dame Hackitt stopped short of recommending an outright ban on the practice. Yet since the publication of her findings, there continue to be calls to remove them – most recently from the London Assembly.

To remove desktop studies as a route to compliance entirely, however, would be a step too far. With just six accredited fire test facilities in the UK, and only one of those able to test full-scale cladding systems, we do not have the capacity to undertake full-scale tests for all building systems.

Desktop studies, and the accompanying assessments and engineered judgements used to evaluate building materials more generally, have an important role to play – but only if administered by the right people, basing their decisions on the right information and established engineering principles.

What we need to see now is the industry working with the regulatory bodies to define a more robust system to ensure they are used in a safe and responsible way – with no corners cut.

Stronger standards are needed

The government has commissioned the British Standards Institution to develop a new standard to determine how and when assessments should be used in place of tests.

As an industry, we need to help shape this new protocol. Our efforts should be focused on two core areas: data and competency. Dame Hackitt highlighted the importance of using “relevant data” as the basis for assessments – we need clear and robust parameters for what this means in practice. 

“Too often studies or assessments have been based on tests which do not adequately reflect real conditions or modern construction techniques”

While full-scale fire testing is not feasible for all construction systems, fire testing must still form the bedrock of any assessment or study. Crucially, the focus should be on testing system performance rather than materials in isolation, understanding the interplay between different construction products, and making sure these systems mirror what’s used on site as closely as possible.

Tests should account for issues such as the impact of openings in the facade or service penetrations in walls and ceilings. Too often studies or assessments have been based on tests which do not adequately reflect real conditions or modern construction techniques.

It’s about collating and recording an accurate pool of data, so that the process of desktop studies and assessments is one of interpolation. This will allow the dots between discrete data points to be connected, replacing an exercise which involves unrealistic extrapolation from ideal, tested systems to those that are actually used in practice.

Assessors must be competent

Dame Hackitt’s recommendation for a new body that would sit above institutions and be responsible for promoting competency on fire safety is welcome.

However, we also need to establish the competence of people in all relevant organisations who are tasked with assessing this information.

“The industry has a responsibility to deliver buildings that are safe. Removing desktop studies would hinder rather than help this ambition”

Dame Hackitt focused on the importance of “competent staff working for an organisation that is accredited”, but this is not enough. Working for an accredited organisation does not guarantee capability of the individual. We need to drill down to the personal level, confirming the competence of not only the assessor, but also the peer reviewer who guarantees their work.

It is up to the industry to set this bar, which could take the form of membership of a recognised fire engineering organisation, such as the Institution of Fire Engineers (at Member or Fellow level), combined with a certain number of years’ experience. Creating a national register of these qualified people and attributing their name to each study will provide a clear chain of responsibility that clients can follow.

Assessors must have the relevant expertise, but we must also provide them with guidance documents to help regulate the system further. The new British Standard should ensure there is a clear and robust process for competent assessors to adopt.

Best practice across the board

The construction industry has a responsibility to deliver buildings that are safe and provide quality of life for their users.

“Crucially, any revisions to the assessment process for cladding materials must be applied to other building products”

Removing desktop studies as a route to compliance would hinder rather than help this ambition. Instead, we must work with government to put in place clear parameters for their conduct, backed by regulation.

Crucially, any revisions to the assessment process for cladding materials must be applied to other building products. There is a real danger that the industry has one set of rules for cladding systems and a different set for other materials; this would create confusion and an unworkable two-tier system.

Only by applying best practice across the board can we provide peace of mind for residents, landlords and the construction supply chain.

Nigel Morrey is technical director at Etex Building Performance

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