The Grenfell Inquiry this week saw more employees from Rydon on the dock. If you don’t already subscribe I thoroughly recommend that you follow the podcasts on BBC Sounds as they come out (weekly). This week we heard from David Hughes (Site Manager), Stephen Blake (Refurbishment Director), Gary Martin (Site Manager) and Daniel Osgood (Site Manager).
The testimonies all make for uncomfortable listening and highlight real gaps in the construction process. In giving evidence Mr Osgood was asked whether he believed that his job was to ensure that work being completed by subcontractors was “compliant” – he replied he “didn’t have the training to do so”. He went on to say that he believed that “anything going on any building is fireproof” and that “all insulation was fireproof as a standard”.
The Project Manager, Gary Martin also got a grilling about foam. He was questioned around the foam selected to seal the windows – he had “assumed” that the insulation was fire resistant. Sadly it seems this assumption was incorrect and that it was wholly inappropriate waterproof seal was used to plug the gap left by the smaller windows – the product didn’t even claim fire resistance. This selection of seals and use of foams remains a real challenge throughout construction – the days of going at a gap with a heart full of hope and a can of “fireproof foam” are surely behind us.
Mr Osgood’s misconception is multi-tiered, but at its core is a concept that I have been raising in talks for the past 5 years. If I google fireproof foam, I get a myriad of results and claims, but the fact is that there is no such thing – a product can be tested for resistance to fire, but no foam is fire proof! Even when a foam is tested to be fire resistant, very close attention should be paid to the scope of use. How often have you removed a ceiling tile to find a large gap oozing orange foam (looking something like an explosion in crunchie factory!) – if you interrogate the test evidence of the foam it is likely that it has only been tested in gaps approximately 10-30mm wide.
SoundProof is another inaccurate claim, products should refer to the levels of sound absorption to reduce reverberation in a space and the sound insulation between spaces which is measured using airborne or impact sound reduction laboratory tests. Sound proofing is often used in claims where hard, dense and imperforate products are used for sound insulation, either airbourne or impact. Products used to improve the quality of sound in a space are absorbent and although they can contribute to reducing sound transmission they have different properties and are generally soft.
We are working with the Construction Products Association, as part of the Grenfell Response, to look at Marketing Integrity. An underlying principle is that performance claims should reflect the test that was carried out, i.e Sound Insulation, Sound Absorption, Fire Resistance or Reaction to Fire.
We must always remember that performance tests are very specific and not interchangeable, for example a product test evidence for reaction to fire can not be used to demonstrate compliance where fire resistance for compartmentation between dwellings is required.
The Inquiry this week is a timely reminder that the ultimate performance of an installed construction product is reliant on a number of things.
- Its intended purpose and appropriate selection and specification
- Test evidence and/or third-party certification for the product for its use
- The installation being done fully in accordance with instructions
and that any interface should be with materials that are equal to or greater than the performance of the products themselves.
Under scrutiny also, particularly in the evidence given by Stephen Blake, was the level of value engineering and impact cost led procurement had on the Grenfell project. Rydon’s bid (£9.2m) was some £700,000 lower than the nearest rival and a staggering £2.1 m less than the original choice contractor. It was within this process that Rydon and façade specialist Harley proposed aluminium composite material (ACM) in either riveted-on or cassette form as a cheaper alternatives to the zinc cladding that was originally specified for the tower (in which Rydon managed to extract greater savings than had been passed on to the client, seemingly to offset in part an error in their bid of £212k).
This substitution and the process was the subject of Mr Hughes cross examining. Mr Hughes admitted that he had approved the decision to switch to the ACM cladding system used, but despite a clause in Rydon’s contract with the Council that said: “The contractor shall not make any substitution for any materials, goods or workmanship… without the prior consent… in writing of the employer.” he did not directly consult building control, the client or the architect about the swap.
Article by Joe Cilia, Technical Director, Finishes and Interiors Sector (FIS)