Stanley wrote: ↑09 Jan 2022, 03:53
Why cladding in the first place? because the buildings had so little original installed insulation. Indeed many had serious fire safety faults that were very conveniently covered up by cladding. Many of the people trapped in unsaleable flats are the victims of these original flaws.
I dont think that is true - from a practical point of view. The use and defects are from a multiple reasons, and the types of cladding vary in application.
It needs to be separated the retro-fit of an external cladding on an existing building, the change of cladding or otherwise to an existing building , the new build with cladding as some or all of the external facings, other faults within the construction giving rise to fire risk, products used for thermal or acoustic insulation.
We can look at these - in a reverse order.
Insulation materials - mostly because I do not have enough information to comment on them as such - There are solid (or blown) insulation products 'Jablite' which is either a form of expanded polystyrene in bubble or sheet form, normally it is tightly encased by concrete blocks or brick and plasterboard, sometimes (and this is the risk factor) other materials. There is I think a vermiculite form of insulation I understand this is a volcanic derived material and has no known fire risk, the polystyrene block ones can be treated to resist fire (though maybe not in the real world - and the chemicals used are questionable on toxicity as they deteriorate). Man Made Mineral Wool is normally by design or treatment fairly robust against flame spread. 'Kingspan' or 'EcoTherm' (trade names effectively), are a chemical polymer gloop solidified and cut to a sheet size, sometimes with a glued face of aliminium foil. it is this that I am unaware which forms are a fire risk, and how and when such risk is mitigated. Note when fitting horizontal and veritical and external angle corner fire break material (effectively concrete or plasterboard) should be fitted - so the insulation is snugly in place (and free from ingress of water).
Typical Fire Risk Elements , assuming Electrical and Gas Standards have not been compromised and other products likely to burn with intensity or toxicity within the internal elements of the building. Internal Doors to common parts and the main external doors of a residential unit to be of half or one hour fire resistance, sealed with expandable material in door or frame to prevent passage of smote. Internal residential doors can also be to same or similar standard but are less effective as realistically people dont always shut their doors. Not often mentioned are window frame materials , and also in summer net or other curtains which can burn easily and spread flame dependent on design of block. I would also check and confirm stopping materials between adjacent dwellings - complete where cables , pipes pass through ( this is typically compromised in flat refurbishments where both common parts and individual flats may have new electrical or water riser or supply systems in place, and holes not sealed (correctly), same applies to floor coverings and choice of materials.
New builds - and Manchester / Salford seem particulary affected by designs. The main external cladding choices , when the type of internal wall system and its insulation have been decided, if (full or thin fired brickwork has been ruled out), has been the kind of sandwich panel ( a metal - normally steel, zinc or aluminum with a type of infill (polymer normally, of some kind, some treated against flame spread), it is important that the panels are pre-ordered to size with all joints correctly sealed - cutting on site will expose the internal form. The metals themselves can be compromised at various states of heating / melting , allowing either the infill, or the underlying insulation (discussed earlier) to be exposed to fire. Again the main 'cover up' would be the hiding of mis-made joints and non existant or incorrect fire breaks. Such designs should be at Building Regulations level, ideally at planning permission, and a full sign off - on the plans and the execution of the plans. Other cladding can include some timber, in shingle or butt/lap plank formats. Some say that wood will char and provide fire resistance that way. Of the few fires involving timber I am aware of - one (Farnborough I think -flats above shops), there were no vertical fire breaks in the low attic spaces so flame chased along the internal rafters helped with a chimney/flue effect). One was from a barbecue outside on add-on balconies made wholly out of timber in terms of flooring, railings and the vertical supports , this form was chosen for architectural effect , fire spread vertically, but less so horizontally but every building would need to be assessed for the actual likely fire route given the location of materials.
One incidence in buildings until recently was no requirement for smoke detectors in individual flats, or even common parts, and how that alert system is connected to a fire call and warning system. It still remains with Cladding, if any test to give rise to what are Fire Class ratings , were carried out, or complied with such regulations, the building data sheets for them are confused and the presence of European Regulations (Items only to be used IF they comply) and UK ones (items used must comply - there is a subtle difference), was unhelpful for supply and installation.
Some external cladding I have noticed are some that appear to be a compacted resin panel , not unlike some artifical flooring panels you might buy. I have seen the standard of application not very good, and am uncertain as to what design plans were actually put in place for them , nor the extent of fire resistance of the panels.
Retrofitting - perhaps the most difficult to look at, as actually not many buildings have been done, and most have been in the public sector or housing association world. Again the main cover up is one of any underlying joints and fire break materials being omitted with no visual. The Lambeth flats which had a fire were a change from single glazed crittall steel framed windows with a painted asbestos sheet decorative infill to PVCu double glazed units with a coloured insulated PVCu infill feature panel. The type of flats were ones where an entire facing was a vertical strip of such windows, with a narrow thin wall above to the full width upper windows again changed for PVCu and repeat as stacked maisonettes. The entire original 1970s design of essentially 4 / 8 storey low rise blocks had little structural materials other than poured concrete floors and edge uprights. It is probable the windows did not have an internal fire resisting thermally insulated sandwich in them (most double glazed powder coated alimium ones which are the present preferred ones do. There have been some high rise 'system built' blocks which have had their concrete external panels replaced with steel insulation sandwich ones (watney market in East London being one I am aware of). Any other specific examples I would be interested in.
Of course such panel use has not been confined to residential flats, we know of hospitals, hotels, offices and even fire stations which have had the sandwich and similar panels as the final facing material.
As to sprinkler systems in flats, these have never been a particular requirment , in part the damage from water can be to the building as annoying as the damage from fire, the insurance concept being that industry needs to continue and the valueable materials and equipment in situ can be protected by a sprinkler - particulary as mill floors etc are open from one wall to the other, workers can leave the building in case of fire by the required multiple fire escapes. For residential blocks, the fire separation is individual units, which can be isolated from each other by the use of the fire resisting materials , and stay put is acceptable unless close to the source of fire and a limited fire escape route - or wait on a balcony for safe rescue- is normally sufficient. Residents are also encouraged not to bring in likely fire materials - like portable gas or parrafin heaters