Frustrated Fa?ade Fabricators

The Centre for Window and Cladding Technology and the Society of Fa?ade Engineering within the Chartered Institution of Building Services Engineers have collaboratively published Guidance on the meaning and consequences of the Building (Amendment) Regulations 2018. While architectural designs with widely varying Fenestration continue to win Planning Approvals the practical and commercial frustration of those Specialist Manufacturers and Contractors who fabricate Fa?ades can be read through the pages of the CWCT-SFE Fire Guidance - Issue 1 September 2020.

https://www.cwct.co.uk/pages/cwct-sfe-fire-guidance

The publication was overseen by the Centre for Window and Cladding Technology Technical Committee and the Society of Fa?ade Engineering Fire Committee, with the full title of CWCT-SFE Fire Guidance as:

The Building (Amendment) Regulations 2018 Regulation 7(2), Regulation 7(3) and Requirement B4 Technical guidance for interpretation in relation to the external walls and specified attachments of Relevant Buildings in England.

The authors very clearly say that this guidance is not intended to "bypass" the 2018 amendments to Building Regulation 7, Requirement B4-(1) of Schedule 1. of the 2010 Building Regulations, or the Statutory Guidance contained in either Volumes 1 or 2 of Approved Document B for Fire Safety, 2019. Written all over the document is a Disclaimer:

"CWCT and SFE accept no duty of care, obligation or liability, whatsoever, to its members or others, in relation to the use of this guidance for any purpose."

The reader will appreciate that Issue 1 has taken since 21 December 2018, when the Building (Amendment) Regulations came into force, to be thrashed out in many meetings. It is an important exercise in Technical writing among many interested parties following the Government's proclaimed "Ban" on combustible materials after Grenfell Tower fire of 14 June 2017, but which was not actually a Technical Ban. Far from it, for good reasons.

A legal amendment to Regulation 7 the 2010 Building Regulations was used to deliver the "Ban". This had the benefit of the Government not having to revise the Approved Documents published under Section 6 powers in the 1984 Building Act.

https://www.legislation.gov.uk/uksi/2018/1230/introduction/made

Regulation 7 became Regulation 7(1), and a supplement was issued for 7(2), 7(3) and 7(4) rather than an update to the Materials and Workmanship Approved Document, last issued in 2013 to take account of the Construction Products Directive. 7(4) defined the "relevant buildings" it applied to, 7(2) insisted upon Class A2-s1,d0 to BS EN 13501-1 for the External Wall as a single criteria, and 7(3) listed all the exemptions.

https://www.gov.uk/government/publications/material-and-workmanship-approved-document-7

As the CWCT and SFE say, knowing the limitations and exemptions matter:

3 TERMINOLOGY “With the new exemptions given by regulation 7(3), appropriate use of terminology is now more important than ever.” [Page 13]

It is worth reading what the CWCT and SFE consider "appropriate":

Infill panel “Translucent or opaque filler or facing material, either of one piece or an assembly, installed within a surrounding frame (BS EN 13119:2016).”

Adding:

“In the context of this document, infill panels are considered as opaque panels only.”

The CWCT and SFE have chosen to limit the definition of Infill Panel from that in BS EN 13119: 2016 Curtain Walling. Terminology to only opaque Infill Panels. Regulation 7(3) exemption (j) is for window frames and glass. By which the CWCT and SFE reasonably understand is meant "vision glass". Glass faced Insulated Infill Panels are not meant to be exempted by 7(3)(j). Some opaque Infill Panels can be uninsulated. But where Insulated Infill Panels are present they are undoubtedly opaque, and an:

Insulation product “A prefabricated product, with a high thermal resistance, which is intended to impart insulating properties to the substrate to which it is applied.”

The question of insulation is of course important. Having identified that BS EN 13119:2016 talks about “filler” for Curtain Walling the CWCT and SFE do not include a definition of “filler” in their Terminology. They know the controversy in Footnote 4. of Advice Note 1. published on 30 July 2017. The "For the avoidance of doubt..." Footnote that before Regulation 7 was amended as a "Ban" had thrown fabricators into disarray:

It was then, in my view, that the Ministry lied about Aluminium Composite Material being included within Paragraph 12.7 of Approved Document Part B Volume 2. It really mattered for Curtain Wall, which many of the CWCT and SFE members as Manufacturers and Contractors who fabricate Fa?ades are concerned with. Curtain Walling is manufactured to a harmonised Standard BS EN 13830:2015+A1:2020 Curtain walling. Product standard.

https://www.dhirubhai.net/pulse/30-minutes-dame-judith-hackitt-approved-document-part-ian-abley/

If “filler” meant Infill Panel “either of one piece or an assembly” from at least 2016 for Curtain Walling are the CWCT and SFE saying that Paragraph 12.7 did include the UNINSULATED Infill Panels of Curtain Walling?

I hope not. Paragraph 12.7 was only about Insulation Materials and Products. But on Page 9 the CWCT and SFE are scrupulous not to criticise the Approved Document in the way a TECHNICAL CHANGE was introduced in 2019, to align with Footnote 4. They copy:

10.6 ADBv1 (2019) and 12.6 ADBv2 (2019) “In a building with a storey 18m or more in height (see Diagram D6 in Appendix D) any insulation product, filler material (such as the core materials of metal composite panels, sandwich panels and window spandrel panels but not including gaskets, sealants and similar) etc. used in the construction of an external wall should be class A2-s3, d2 or better (see Appendix B). This restriction does not apply to masonry cavity wall construction which complies with Diagram 8.2 (9.2) in Section 8 (9). Where regulation 7(2) applies, that regulation prevails over all the provisions in this paragraph.”

The CWCT and SFE recognise Issue 1 will change. Maybe when the Grenfell Tower Inquiry has taken a view on Footnote 4. the CWCT and SFE will catch up and revise their Fire Guidance beyond an uncritical repetition of 10.6 in ADBv1 (2019) and 12.6 in ADBv2 (2019). Future work is explicitly expected, and clarifications invited.

1.9 Future work “The amendments to the Building Regulations and Approved Document B guidance have introduced several challenges and apparent inconsistencies which need addressing by designers. They have also raised questions that cannot readily be answered with current testing methodologies.” [Page 10]

Take for example in the Terminology:

Shadow box “Spandrel feature typically incorporating clear glass (to provide visual continuity with vision areas), a cavity and an opaque infill. The cavity creates the illusion of depth behind the glass and changes the visual appearance of the glass externally.”

The Shadow Box "clear glass" is the same as the "vision glass" in 7(3)(j), but the "opaque infill" of the back of the Shadow Box is an Insulated Infill Panel, and that is within Regulation 7(2). But there is another matter. Future work is required on the subject of Fire Resistance for Infill Panels, whether insulated or uninsulated, with a Shadow Box as a particular kind of Insulated Infill Panel crossing Compartment Floors. That is what is meant by “Spandrel”. There are also Infill Panels that cross Compartment Walls. Frames must cross Compartmentation. The simple case of an Infill Panel is where no Compartment Line is crossed by any Frame.

6.2 Spandrel/infill panels “Spandrel/infill panels are not covered by any of the exemptions given in regulation 7(3).” [Page 37]

The CWCT and SFE clearly question this legal position by looking at the sub-components that go to make up Infill Panels. They want to use the Regulation 7(3) exclusions list, with more precision. Pages 37 to 45 are devoted to making appeals to the Ministry of Housing, Communities & Local Government for clarifications, and makes for fascinating detailed reading. No doubt CWCT-SFE Fire Guidance, Issue 2 will further address subtleties, which Regulation 7 cares nothing about. Before digressing into the detail of Section 6, CWCT-SFE Fire Guidance, Issue 1 grapples with fraught questions of wider significance the MHCLG might be moved on during the Grenfell Tower Inquiry.

2 MATERIALS “Combustible elements can be used in ‘products’ or ‘components’ provided the complete ‘product’ or ‘component’ has been tested and classified in accordance with EN 13501-1, and has achieved a classification of A2-s1, d0 or better. An example of this would be polyester powder coated aluminium. The powder coating is combustible, but when tested with an aluminium substrate, the component can achieve class A2-s1, d0. This is discussed further in section 6.2.” [Page 11]

The CWCT and SFE insist:

2.2 EC Decisions “The MHCLG FAQ confirms that products which have been deemed by European Commission decisions to meet Class A2-s1, d0 or A1 can be considered to meet the new requirements.” [Page 12]

The CWCT and SFE are referring to the Guidance - Building (Amendment) Regulations 2018: frequently asked questions, last updated 21 January 2020.

https://www.gov.uk/government/publications/building-amendment-regulations-2018-frequently-asked-questions/building-amendment-regulations-2018-frequently-asked-questions

6. Can I use products which are classified A2-s1, d0 or A1 by delegated acts or European Commission decisions? “Yes. The new regulations state that external walls and specified attachments must be constructed of materials achieving Class A2-s1, d0 or A1, when classified in accordance with BS EN 13501-1:2007+A1:2009. Products which have been deemed by European Commission decisions to meet Class A2-s1, d0 or A1 can be considered to meet the new requirements.”

The MHCLG have not thought this through. The European Commission, which the UK has departed from, was only talking about UNFINISHED Aluminium metal being deemed Class A1 as the least Reaction to Fire classification within BS EN 13501-1. Not decoratively FINISHED Aluminium. These are rather old decisions too.

European Commission Decision (96/603/EC) of 4 October 1996 is titled:

Establishing the list of products belonging to Classes A 'No contribution to fire' provided for in Decision 94/611/EC implementing Article 20 of Council Directive 89/106/EEC on construction products

https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:31996D0603&from=EN

European Commission Decision (2000/605/EC) of 26 September 2000 is titled:

Amending Decision 96/603/EC establishing the list of products belonging to Classes A ‘No contribution to fire’ provided for in Decision 94/611/EC implementing Article 20 of Council Directive 89/106/EEC on construction products.

https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32000D0605&from=EN

(2000/605/EC) says the listed materials in (96/603/EC) are to be considered having a Class A1 Reaction to Fire without the need for testing. Yet it also refers back to European Commission Decision (2000/147/EC) of 8 February 2000, titled:

Implementing Council Directive 89/106/EEC as regards the classification of the reaction to fire performance of construction products.

https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32000D0147&from=EN

Which contains Table 1:

CLASSES OF REACTION TO FIRE PERFORMANCE FOR CONSTRUCTION PRODUCTS EXCLUDING FLOORINGS

As far as I can see (2000/147/EC) Table 1. is identical to Table 1. in BS EN 13501-1:2018 Fire classification of construction products and building elements. Classification using data from reaction to fire tests.

The list of materials in (96/603/EC) are elevated to Class A1. in (2000/605/EC) no matter how they smoke or melt as potentially flaming droplets.

This is important, because if an allowance is made for decoratively finished Aluminium to avoid the 750°C Furnace, as the equipment in BS EN ISO 1182 Reaction to fire tests for products. Non-combustibility test required for Class A1, then why not any of the other materials listed in (2000/605/EC)?

It seems that decoratively FINISHED Aluminium should be either tested to obtain Class A1, or tested to Class A2 with a proper measure of smoke and flaming droplets. The decorative finish manufacturers cannot promote themselves because UNFINISHED Aluminium metal is deemed Class A1 to BS EN 13501-1. The (2000/605/EC) exemption might apply to “mill finished” Aluminium, but should not absolve finishes on Aluminium from Furnace testing.

https://www.dhirubhai.net/posts/ableyian_around-150-people-forced-to-evacuate-after-activity-6713388811432407040-NOCQ

The CWCT and SFE are right to caution in their Terminology about England that:

Non-combustible “A material/product classified as class A1 in accordance with BS EN 13501-1. It should be noted that in some countries A2 is regarded as non-combustible."

The CWCT are more inclined to question (96/603/EC) as amended by (2000/605/EC) when it comes to 6.1 Glazing. They explain the EC stated “None of the materials in the table is allowed to contain more than 1,0 % by weight or volume (whichever is the lower) of homogeneously distributed organic material.” They say:

“It is not clear on which basis laminated glazing is included in the table because a laminated glass product does contain more than “1% by weight or volume” of organic material that is not homogeneously distributed. Further clarification is being sought on this issue, and until forthcoming it is our interpretation that this EC Decision cannot be used to exempt laminated glass.” [Page 33]

Neither should (2000/605/EC) be used to exempt anything other than unfinished Aluminium. But they want an exemption. Laminated glass can be used as "vision glass" under 7(3)(j) but cannot be used in opaque Insulated Infill Panels under 7(2), other than for the extension of the glass front in the form of Shadow Boxes. The (2000/605/EC) exemption is applied to unprocessed Glass, but does not absolve processed Glass from Furnace testing. Glass processors and Laminators among them are limited by Regulation 7 (2018), as should be the finishers of Aluminium, and the Powder Coaters among them.

Regulation 7 can get silly, as the CWCT and SFE point out.

“A film applied to any external surface would not be exempt from regulation 7(2). A film applied to the internal surface of a vision glass unit would be exempt.” [Page 34]

To get over this the CWCT and SFE might lobby to better define Regulation 7 as law based in Building Science, and move beyond the EC decisions we are no longer bound to. It is really important that some better Building Science for Fa?ade fabrication is established.

10.14 ADBv1 (2019) and 12.15 ADBv2 (2019) “The provisions of regulation 7 apply in addition to requirement B4. Therefore, for buildings described in regulation 7(4), the potential impact of any products incorporated into or onto the external walls and specified attachments should be carefully considered with regard to their number, size, orientation and position.” [Page 9]

It is very important to recognise the MHCLG’s Approved Document Part B (2019) reference to “number, size, orientation and position.” The CWCT and SFE note the uncertainty on what amounts to architectural Fenestration.

5.1.1 Framing materials “Several different materials may be used for the frame profiles of a curtain wall or window system. These include aluminium alloys, other metals such as steel or bronze, timber, and PVC-u. Whilst all curtain wall (and window) frames are exempt from the limits of combustible materials introduced by regulation 7(2), all external walls must also meet requirement B4, and this may introduce limits on the use of certain combustible materials.” [Page 21 to 22]

The CWCT and SFE should worry about architectural Fenestration in their Fire Guidance:

“The risk of external fire spread will depend not only on the combustibility of the materials used, but also on their exposure, extent and separation between frames.”

The CWCT and SFE say:

“This is an area of significant uncertainty. There is no published evidence to suggest that combustible curtain wall or windows frames pose a significant risk of external fire spread, or if they do, at what separation distance between frames the risk becomes insignificant.”

But separation did concern regulators about Windows, Doors and Balconies in the Post War Fire Grading Reports when Fenestration was prescribed, before the commercial rise of Curtain Walling in 1960s. Curtain Walling became possible in the First National Building Regulations of 1964/1965 through new thinking about "unprotected area". 

Windows are NOT Curtain Walling, even when arranged in a “screen” as a series of linked Windows. Windows are a product with RIGID non-Racking Frames with Glazing, often with opening lights for Ventilation. Curtain Walling is a system that is FLEXIBLE to allow the frames to Rack but the Glazing not to leak air and water, or to be shattered by that Movement. This is a fundamental Technical distinction. Window manufacturers are proud of the performance of their RIGID non-Racking Frames. Fa?ade Contractors compete by constantly advancing Curtain Walling to accommodate Movement of the FLEXIBLE Frames Racked on the Primary Structure, without the system failing.

The CWCT was created to raise the Standard by which those systemised building envelopes are tested. The SFE lives by the CWCT Standard for systemised building envelopes and other Guidance, including Guidance on Built Up Walls. Now this Fire Guidance.

Quite rightly the CWCT and SFE refer to BS EN 12519:2018 Windows and pedestrian doors. Terminology. This is important because RIGID fixed or opening Window products are manufactured to BS EN 14351-1:2006+A2:2016 Windows and doors. Product standard, performance characteristics. Windows and external pedestrian doorsets. They are NOT to be confused with Curtain Walling:

Window “Building component or multiple components for closing an opening in a wall or roof that may admit light and/or provide ventilation (BS EN 12519:2018).”

Window frame “Component forming the perimeter of a window, enabling it to be fixed to the building structure (BS EN 12519:2018).”

However in 5 FACADES and in 5.1 Stick or unitised glazed curtain walling [Page 21] the CWCT and SFE seem pleased to join with the MHCG FAQ in eliding the Window and Window Frame with Curtain Walling and Curtain Wall frames.

9. How does the ban apply to curtain walls? “Window frames are exempted from the requirements of regulation 7(2) under the provision of regulation 7(3). Conventional curtain walls consisting of mullions, transoms and glazing can be considered as a window frame. Regulation 7(3) exempt window frames from the requirements of regulation 7(2) this exemption includes all component parts of a windows frame.”

Windows are NOT Curtain Walling. The CWCT and SFE should say so.

The MHCLG’s phrase “Conventional curtain walls consisting of mullions, transoms and glazing can be considered as a window frame” is illiterate. How can glazing be a frame?

The CWCT and SFE make their own exceptions on the basis of the MHCLG’s use of the word “conventional”. The MHCLG say that “… spandrel panels and/or other opaque insulated panels in curtain walls are not exempted in regulation 7(3).” [Page 21] That is true. Yet the practical sense of treating the Infill Panel as part of the High Rise External Wall for Reaction to Fire in BS EN 13501-1, while the Window or Curtain Wall frames can fail in no time, allowing the High Rise Class A2-s1,d0 Infill Panel to fall out, is lost on me.

From a Fire Resistance point of view both frames and panels are “unprotected area”, of course, with Fire Resistance to BS EN 13501-2. The CWCT and SFE say:

“The MHCLG FAQ confirms that the ‘exemption includes all component parts of a windows frame’. This would include the main frame material, any finishes, thermal breaks and minor ancillary components such as setting and location blocks, drainage spouts, ironmongery and actuators that are part of the door or window assembly etc. Seals, gaskets, fixings, sealants and backer rods are explicitly exempt by regulation 7(3)(h).” [Page 21]

The Insulated Infill Panel of a Window is included in Regulation 7(2), BECAUSE it is NOT one of the “component parts of a windows frame”. The mention of Windows (sic) FRAME is important. The CWCT and SFE insist on extending the MHCLG’s FAQ elision to 5.1.3 Non-glazed spandrel/infill in curtain walling [Page 23].

Meanwhile, the CWCT and SFE Terminology does not refer to Doors, Door Frames, or Doorsets, also manufactured to BS EN 14351-1. Sliding Doors are often used on Balconies as Windows, and “French Windows” are Doors, often with just a balustrade to prevent falls. Whole Doors are exempt in Regulation 7(3), including their Insulated Infill Panels. A tricky difference. The “Juliet Balcony”. Though I don’t understand why “Juliet guarding” is considered “Exempt from regulation 7(2)” by virtue of being Glass, but a metal “Juliet Balcony” would be a “specified attachment”. [Page 20] Maybe I have missed the CWCT and SFE reasoning on that. But they say:

“Juliet guarding/barriers are not specifically defined as either the external wall or a specified attachment.” [Page 36]

If they are not in Regulation 7(3) Juliet Balconies are surely covered by Regulation 7(2). Is that not the case, regardless of the absence of an MHCLG FAQ question or answer?

Balconies of all kinds as “specified attachments” in Regulation 7 have a new definition in BS 8579:2020 Guide to the design of balconies and terraces. Noted by the CWCT and SFE in 5.3 Balconies and terraces [Page 29 to 32]. This needs Future work too.

The Fenestration matters, though Approved Document Part B places no architectural constraint on “number, size, orientation and position” of Windows and Doors, Balconies and other “specified attachments", the arrangement of Curtain Wall, or any other Built-Up Wall construction, except for the Calculation of “unprotected area” as a PERCENTAGE of the Fa?ade. The CWCT and SFE insist:

“There is no published evidence to suggest that combustible curtain wall or windows (sic) frames pose a significant risk of external fire spread, or if they do, at what separation distance between frames the risk becomes insignificant.” [Page 22]

That is the most fascinating of statements, but rather misses the point about the lack of Building Science. It has a profound importance for 5.2 Built-up walls [Page 24 to 28].

Where much Future work is needed.

BS 8414 testing and BR 135 assessment, with BS 9414 assessment in lieu of testing, as an option for all non-"relevant buildings" outside of Regulation 7(4), is not going to tell you much about Fenestration in Built Up Walls. The CWCT know that neither Part of BS 8414 is suitable for testing Curtain Walling. In BS 8414 there is no Fenestration tested beyond the detailing of the “Hearth”, meant to simulate the top of a Window on the Fire Floor. No Window and Door opening details, or Balcony projections and recesses. No reality in the architecture is tested in BS 8414. Only a blank, flat, "L" shaped wall.

https://www.dhirubhai.net/pulse/what-do-governments-seven-full-scale-tests-tell-us-grenfell-ian-abley/

Meanwhile BR 187 is based on the "unprotected area" principle of separation between buildings. That does not insist upon Fire Resistance as separation between annealed glazing in frames that can burn or melt, all expected to fail in a fire. When any Infill Panel will fall out. Windows and Doors that might be open for ventilation. The openings in an opaque wall, all of which, with enough distance between buildings, can be 100% Non-Fire Resisting.

Except, of course, for Fire Resisting Cavity Barriers required in Built Up Walls with cavities, particularly around openings, or Fire Resisting Fire Stopping to Fa?ades that cross Compartment Floors and Walls, like Curtain Walling.

https://www.dhirubhai.net/pulse/bba-certificate-084510-missing-cavity-barriers-grenfell-ian-abley/

That is all certainly based in a lack of Building Science about the Fa?ade, leaving the professional response to Requirement B4-(1) in Schedule 1. of the 2010 Building Regulations incomplete.

The Post-War Fire Grading Reports have a point for the Future. One lost in the Past. A closer look at "Roll-Over" at Garnock Court (1999), Lakanal House (2009) and Grenfell Tower (2017), among other incidents, suggest the Reaction to Fire and the Fire Resistance of the “number, size, orientation and position” of architectural components of Fa?ades matter.

How is not well enough known.

Issue 1 of the CWCT-SFE Fire Guidance needs to be taken seriously. Issue 2 required.

Published evidence of Fire Safe Fa?ade Engineering is needed, abstracted into principles that the non-Specialist client, consultant and contractor can understand.