The cladding conundrum: Discussing the Valencia high-rise fire

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Alex Dodd EngTech MInstRE DipFD, Senior External Wall Consultant, CHPK Fire Engineering, looks at the Valencia high-rise fire

What has previously been viewed by many as a failure of British building stock since Grenfell 2017, is now being recognised as a global epidemic.

It is no longer a case of it, but when. The UK took rapid steps following Grenfell to survey, test and set up funding for the removal of Aluminium Composite Material.

Unfortunately, these lessons on our building failure have yet to be learnt or introduced across the world stage as on the 22nd of February 2024 at approximately 5:37pm a Highrise block in Valencia, Campanar was viewed to have a fire on 9th storey balcony.

The building was a combination of 10-storey and 14-storey’s containing commercial premises up to the 2nd storey and 138 residential apartments, linked by a panoramic lift.

The building also consisted of recessed balconies and terrace balconies on the roof level.

Cladding concerns

There was an assumed occupancy of more than 400 people of varying ages and physical abilities.

The building cladding was completed in 2008/09 with an Alucoil Aluminium Composite Material (ACM), with a Polyethylene (PE)core.

This cladding material was similar to that of Grenfell tower, including its design.

It was used as non-insulating architectural surface with a separate insulation layer that formed the cavity wall.

This insulation type was different from that of Grenfell, in the Valencia fire it was speculated by external sources as a stone wool but this has not been confirmed.

The PE core within the ACM is a Thermoplastic material that is evidenced to release 45MJ/kg of energy, this is equivalent to petrol at a range of 44Mj/kg – 46MJ/kg.

So theoretically we have a building covered in a solid state petrol and if it had been at night like Grenfell the loss of life would be unimaginable.

What happened next has regrettably led to 10 confirmed deaths, more missing and that number is likely to increase as search and recovery operations continue.

When the fire started on the nineth-floor video evidence from bystanders shows the rapid-fire development across the envelope of the building.

The fire spread from videos and pictures show that within 2 minutes 5.39pm it has spread to the balcony below and by 6.11pm it had engulfed the left hand side of the building and the top central parts.

Given the year of construction and the building regulations used in Spain at the time of construction allowed for the use of a M1 class cladding, this is similar to the standard in France.

M1 class or equivalent to UK national class 0 can be achieved with varying product types, petrol-based products, retardants, timber and more.

This is because using tests like BS476 allows for an unlimited Gross Calorific value in MJ/Kg in parts 6 and 7.

If we consider the BS476:7 test briefly, when testing a product, the test sample is seated in a water-cooled frame.

This allows for the edges of the PE core to not exceed more than 35°c.

As such we are limiting the edges of the test sample to a maximum temperature.

The test sample is also clamped in position with a 20±5mm overlap to protect the exposed edges where there is no or very limited ability in which this combustible core could ignite.

Therefore, there is a reliance on the outer surface leaf material (aluminium) being limited in combustibility to withstand fire to achieve a class 0 for a petrol-based products in essence.

Under similar test conditions in UNE:23727:1990 this has allowed materials of Euroclass B, C, D and E materials into a market as class M1.

If the system has been tested to LEPIR 2/BS8414 test would this have given a different outcome? You would expect so, but these certificates are waved around to façade engineers like the contractors have been given Willy Wonka golden ticket.

These tests are not realistic to actual building designs or the local environmental conditions.

The majority of test rigs are usually inside so not exposed to wind conditions which has been seen as one of the contributing factors in the Valencia fire.

If we are to test facades with wind, are we testing to the 50-year wind load for that area and region like we do for glazing? If we do, then we will be required for specific tests for each building or mean that producers do a range of tests.

These tests do not contain balconies within the test rig and testing with these presents challenges too.

Slab thickness, projections, spans, balustrade infills and are not tested with human factors like children’s toys, artificial grass, table, and chairs parasols like evidenced in the Valencia fire.

These tests can also be manipulated depending on the time of year undertaken as lower ambient temperatures in winter mean the air is denser and the materials are able to perform longer.

There is no dedicated set cavity barrier height and the difference in these heights can have increase in temperature of over 100°c.

Would sprinklers have aided in preventing the fire spread across the building? As of yet it is unclear where or how the fire on the balcony originated.

If it did originate from the balcony, sprinklers would have very little effect in delaying or preventing the spread.

Any sprinkler for internal application is designed for one head activation.

Multiple actuations would have compromised the hydraulic water pressure and would have been ineffective in preventing fire spread.

So, during the Valencia investigations which will take place will we assign guilt or blame and what lessons can be learned?

What we can learn from the Valencia fire

It was previously inspected by The College of Industrial Technical Engineers Vice President Esther Puchades who commented: “The reason the [building] burned so fast is because of this type of cladding.” If it was known and identified that this cladding could burn so fast, why was it not removed?

 Are the manufacturers Alucoil to blame? Or had they followed the test standard and the designers, and engineers had not understood how these tests had been undertaken? Or was it a case of value engineering being overvalued?

Lessons which can be learned from this fire will come out fully as part of the investigation.

However, although space separation may have been applied to the minimum required distance, there is still the inherent risk that radiation has the ability to ignite neighbouring buildings, putting further stress and resources on firefighting operations.

As evidenced from the pictures and videos of the balconies, the laminate glass balcony balustrades appeared not to aid or contribute to the further development of fire across the external envelope of the building.

Should this be reconsidered and evaluated for its contribution on new builds and remediation?

Firefighting operations, as shown in the videos, pictures and news there was some heroic rescues; but the manoeuvres, risk and reactive measures could only be evidenced that this was as unprecedented as was Grenfell.

Do we need to provide further training to firefighters and give them a deeper insight and understanding of the now euro classifications, material performance and testing?

Or should we not need to because buildings should not be clad in a solid substrate made of petrol?

Going forward should Spain and the world stage follow suit and look to the UK for how we have addressed our building failures both historic and modern.

The UK has now adopted controls to hopefully prevent any building failures of the future through Acts, regulations, and legislation.

This article was originally published in the April 2024 issue of International Fire & Safety Journal. To read your FREE digital copy, click here.

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