Knavish Knowledge Keepers
We must, it seems, wait for the Grenfell Tower Inquiry to get to at least four important pieces of evidence that suggest the Secretary of State around 2002, responsible for the Approved Documents, including Part B Fire Safety, knew Class 0 could be combustible.
It is known that the Secretary of State in the Natural Person of Nick Raynsford had been warned in the Select Committee on Environment, Transport and Regional Affairs First Report of 5 January 2000 about the potential risk which could be posed by fire spread involving external cladding systems. This Select Committee investigation had been prompted by the fire at Garnock Court, Irvine, Ayrshire, Scotland on 11 June 1999.
POTENTIAL RISK OF FIRE SPREAD IN BUILDINGS VIA EXTERNAL CLADDING SYSTEMS
https://publications.parliament.uk/pa/cm199900/cmselect/cmenvtra/109/10907.htm
Regulations pertaining to the fire safety of external cladding systems 7.(b) “External surfaces (and hence cladding) closer than 1 metre to another building should be of a material classified as 'Class O' for spread of fire [24]”
[24] 'Class O' is a classification designed to limit the fire propagation and the spread of flame over the surface of a material. This classification is defined for the purposes of the Building Regulations, and is used for critical situations where a particularly high standard of performance is required. It is measured through a combination of test results from BS476: Part 6: 1989 and BS476: Part 7: 1987. It should be noted that both 'Class O' and 'limited combustibility' are different from the classification 'non-combustible', which is the highest level of material performance on exposure to fire, and is measured by reference to test BS476: Part 4: 1970 or Part 11: 1982. In no circumstances are external cladding systems required to be non-combustible.
Original Emphasis. Of course the Committee meant Class 0, as a Government's extension to the numerical series 3, 2, 1 of BS 476 Part 7, not Class O the letter. Class 0 is not defined in any British Standard. It belongs to the Ministry. The printed version of the Environment, Transport and Regional Affairs Committee Report ordered by the House of Commons to be printed into the Public Record on 14 December 1999 had this warning to the Minister concerning Paragraph 7.(b) as Reference 6 on Page viii.
What did John Prescott as the Deputy Prime Minister and Nick Raynsford as the Minister called by the Select Committee do about that warning from ETRAC in 2000?
It appears Raynsford’s Ministry commissioned RADAR Reports to look at the way in which National Classifications of Fire Performance could be compared to the European Classification in the Parts of series BS EN 13501 Fire classification of construction products and building elements. It is not known what “RADAR” means, though it sounds like it could be an acronym. The RADAR Reports have never been in the Public Record.
However, they are available to the Lawyers, and perhaps the Core Participants, of the Grenfell Tower Inquiry. The RADAR Reports were identified at the start of Phase 2 by Stephanie Barwise QC, Omar Eljadi, Marie-Claire O'Kane and Dalton Hale in:
PHASE 2, MODULE 1: OPENING SUBMISSIONS ON BEHALF OF THE BSR REPRESENTED BY BHATT MURPHY, BINDMANS, HICKMAN & ROSE, AND HODGE JONES & ALLEN
https://assets.grenfelltowerinquiry.org.uk/BSR%20Team%201%20Mod%201%20Opening%20subs.pdf
3. The Seeds of the Disaster 3.2 “Underlying all this, Central Government has much to answer for, in failing to overhaul the Building Regulations, but particularly the guidance document Approved Document B (“ADB”). ADB is based on a 1946 post-war document, should have been overhauled in 2000 (as Government knew [5]) and is not fit for purpose. Though the guidance was in fact understood by many designers/contractors, product manufacturers deliberately exploited the ignorance of other designers and contractors, relying on their lack of understanding of ADB.”
[5] Radar Report {CLG00000949}, {CLG00000950}, {CLG00000951}
The Lawyers gave their opinion about what they thought should have happened with Class 0 in their Section 7. Fundamentally Flawed Building and Product Testing Regulations, but what should have happened is not what in fact happened:
7.2 “When the Euroclass reaction to fire gradations A-F were introduced into ADB in 2000, Class 0 should have been abolished. [60] It is an outdated and confusing classification which relates solely to surface spread of flame but gives no indication of reaction to fire. Class 0 has instead created a completely false sense of security amongst industry at large, and possibly designers and contractors at Grenfell.”
[60] Radar Report 23.5.00 {CLG00000949}, {CLG00000950}, {CLG00000951}; BRAC working party meeting 15.04.02 {CLG00000720}.
The three RADAR Reports and the notes of the Building Regulation Advisory Committee working party meeting of 15 April 2002 are not yet available on the Grenfell Tower Inquiry site, and may not be for some time. But hopefully sooner rather than later we shall read:
- CLG00000949 – RADAR
- CLG00000950 – RADAR
- CLG00000951 – RADAR
- CLG00000720 – BRAC 15 April 2002
The Building Regulations Advisory Committee as an advisory non-departmental public body established in 1962, to advise on the First National Building Regulations in 1964/1965. BRAC is constituted under Section 14(1) of the 1984 Building Act and members are directly appointed by the Secretary of State to a committee so that they can be consulted. BRAC is where the Minister meets the appointed leaders of the construction industry.
https://www.legislation.gov.uk/ukpga/1984/55/section/14
BRAC publishes Annual Reports these days, and Member appointments are declared, but never Minutes of Meetings. Presumably the BRAC Minutes of 15 April 2002 refer to the RADAR Reports. They may show advice given by BRAC to Nick Raynsford as the Minister on what to do about the ETRAC warning.
https://www.gov.uk/government/organisations/building-regulations-advisory-committee/about
There is nothing to find published from BRAC, but I took to Google to search permutations of "RADAR". The Soundproofing Forum has an old website from 2002 to 2009 that shows it had submitted a Regulatory Impact Assessment concerning the Building (Amendment)(No. 2) Regulations 2002. That involved Schedule 1 to the Building Regulations 2000. The Soundproofing Forum were concerned with Part B - Fire Safety as it related to Part E - Resistance to the passage of sound, addressed in the Approved Documents published under Section 6 of the 1984 Building Act.
https://soundproofingforum.co.uk/
Regulatory Impact Assessment: Signed 16 November 2002
Section 2: Amendment of Part B (Fire Safety) of the Building Regulations: Recognition of Harmonised European System of Fire Testing
Outline 10. “The adoption of a harmonised system of reaction to fire [2] and fire resistance [3] testing and classification across the European Union, in support of the CPD, means that Approved Document B requires revision to incorporate the new European test and classification methods. The current (2000) version of Approved Document B currently only references the BS 476 series of fire tests to classify building materials/products.”
https://soundproofingforum.co.uk/guides/bregs/02.htm
[2] Official Journal of the European Communities L50, pp.14-18, 23/2/2000 “Commission decision of 8 February 2000 implementing Council Directive 89/106/EEC as regards the classification of the reaction to fire performance of construction products”.
[3] Official Journal of the European Communities L133, pp.26-32, 6/6/2000 “Commission decision of 3 May 2000 implementing Council Directive 89/106/EEC as regards the classification of the resistance to fire performance of construction works and parts thereof”.
The Ministry appears to have provided the Soundproofing Forum with at least some of the information in the RADAR Reports now with the Grenfell Tower Inquiry. The RIA required an estimate of the cost of requiring European testing, rather than merely allow the BS 476 tested Acoustic materials and products to remain on the market:
The issue 20. “It has been recognised that the methodology embodied in the new European tests, while similar in general principle, will significantly affect the results achieved by many products tested under the current British Standard regime. In particular, the new standards are more severe on some currently acceptable products and constructions.”
https://soundproofingforum.co.uk/guides/bregs/03.htm
Nature of Proposed Amendment 26. “In an attempt to determine the likely technical and financial impact of the proposed new test methods for fire resistance and reaction to fire the then DETR helped to sponsor two research projects [4],[5] led by Warrington Fire Research Centre. The research was steered by an Industry Advisory Group, which had representatives from industry who have experience in manufacturing all types of construction products.”
https://soundproofingforum.co.uk/guides/bregs/04.htm
Membership of the “Industry Advisory Group” is not revealed by the Soundproofing Forum, but their RIA suggests there were two RADAR projects:
[4] RADAR 1 Project – Modifications required to Approved Document B following the introduction of new European fire resistance test methods on currently acceptable products and constructions. Warrington Fire Research Centre, May 2000.
[5] RADAR 2 Project – Correlation of UK Reaction to Fire Classes for Building Products with Euroclasses and Guidance on Revision of Approved Document B. Warrington Fire Research Centre, May 2000.
Fire Resistance was concerned with BS EN 13501-2:2003 Fire classification of construction products and building elements. Classification using data from fire resistance tests, excluding ventilation services. For Fire Resistance tests the Soundproofing Forum say:
27. “In the case of the fire resistance tests on construction products, the research showed that products tested by the European test method record test times that are, on average, some 10 to 15% shorter than for those tested by the British Standard test methods. For example, a product achieving 60 minutes under the British Standard test may only achieve 50 to 55 minutes under the European harmonised test. In many cases, this reduction would lead to the product having a lower European classification, compared with the existing classification in Approved Document B.”
28. “The proposal - as recommended by the Industry Advisory Group - is to retain the existing classification system to avoid confusion and market distortion. If the periods of fire resistance recommended by Approved Document B were reduced, to reflect the stiffer European tests, this could lead to a perception that safety standards were being reduced (e.g. a product previously achieving a 60-minute fire rating, that was now only achieving 50 minutes, would be perceived as having a poorer performance even though it had not been altered). This could possibly lead to an increase in insurance premiums.”
29. “Consequently, it is proposed that there is no change to any of the periods of fire resistance given in Approved Document B. The implication for the industry is that, if it wishes to test to the European test methods, it may have to adapt its products, where necessary, to meet the 10 to 15% shortfall in test times. If it did not, it could lead to significantly over-engineered products being entered into the next category down. This will have cost compliance implications for the industry, which are discussed further in Annex B.”
Reaction to Fire was concerned with BS EN 13501-1:2002 Fire classification of construction products and building elements. Classification using test data from reaction to fire tests. For Reaction to Fire tests the Soundproofing Forum say:
30. “In the case of the reaction to fire test the situation is more complex as the European harmonised test does not mirror the British Standard test. Transposition is more difficult as the British Standard tests for "spread of flame", "fire propagation" and "non-combustibility" must be compared to a single new set of tests which has seven classes: A1, A2, B, C, D, E and F. However, on the basis of the 'back to back' fire testing where the two standard regimes were compared for a range of construction products Table 1 contains the proposed transposition for reaction to fire performance.”
That Soundproofing Forum Table 1. summary attributed to the RADAR 2 Project was indeed how the Ministry transposed National and European Classes. A transposition that lasted until Grenfell Tower fire of 14 June 2017, and with the exception of “relevant buildings” in Regulation 7 (2018), extended into Approved Document Part B in two Volumes announced on 5 July 2019. ADBv1&2 (2019) introduced Transposition Table B1., based it seems in the RADAR 2 Project, of which more later.
https://www.gov.uk/government/publications/fire-safety-approved-document-b
The Phase 2, Module 1 Opening Submissions on Behalf of the BSR identify three RADAR documents as part of the CLG evidence. While the Soundproofing Forum suggest two RADAR Projects. It may be that there were three RADAR Projects, or that the Fire Resistance and Reaction to Fire Projects had Parts in their reporting.
There are three published citations of the RADAR 2 Project Reports to my knowledge so far, and it would be fascinating to know of more, should the RADAR Reports not become public until the Grenfell Tower Inquiry is ready:
1. DCLG Report - BRE, The impact of European fire test and classification standards on wallpaper and similar decorative linings, Department for Communities and Local Government, London, March 2012, Paragraph 3.2 and Reference 15
3.2 RADAR2 project - Correlation of UK Reaction to Fire Classes for Building Products with Classes “The RADAR2 project [15], sponsored by DETR, carried out comparative back to back testing of 75 products from eight different product sectors. Six wall coverings were tested, all using calcium silicate board as the substrate. All of the products achieved national, “Class O”, as defined in Approved Document B, when tested for surface spread of flame and fire propagation index to BS 476 Part 6 and BS 476 Part 7 respectively. All but one of the products achieved Class B according to BS EN 13501-1, using the tests to EN 13823 (Single Burning Item (SBI) test) and BS EN ISO 11925-2 (Small flame test).”
[15] RADAR 2 Project – Correlation of UK Reaction to Fire Classes for Building Products with Classes and Guidance on Revision of Approved Document B. Part 1: UK and European Test Data and comparisons between classification systems. (DETR Ref: 39/3/571 cc1848)
2. Academic Paper - C.W. Leung, Department of Building Services Engineering, The Hong Kong Polytechnic University, Hong Kong, China, ‘Flame Spreading Test in Hong Kong and New Alternatives’, International Journal on Engineering Performance-Based Fire Codes, Volume 5, Number 4, p.119-124, 2003, Reference 32.
[32] RADAR 2 Project – Correlation of UK Reaction to Fire Classes for Building Products with Euroclasses and Guidance on Revision of Approved Document B. Part 1: UK and European test data and comparisons between classification systems, WARRES No. 108954, Warrington Fire Research Centre Ltd., Warrington, UK (2000).
3. Article in the Architects’ Journal - Peter Briggs, ‘The impact of changes to approved Document B to accommodate the new Euroclass reaction to fire classification systems – BRUFMA Conference 2002’, Architects’ Journal, 23 May 2002. This is fascinating
“The adoption of a harmonised system of reaction to fire tests across the EU means that Approved Document B (2000 Edition) of the Building Regulations 1991 will require further revision. It is proposed to do this by publication of European supplements for use with Approved Document B. Currently, the classification of building products according to their reaction-to-fire performance is achieved by the BS 476 series of fire tests.
The CEN test methodology developed for Euroclassification of products (excluding floorings) is different from the BS 476 tests.
The field of application of the Euroclassification is identical to the field of application resulting from the CEN tests where the test conditions are determined in relation to the end-use application of the product. If different end-use applications are envisaged for a particular product (eg use of different substrates), this may result in different classifications. The Euroclassification of a product is based on its reaction to fire performance assessed as its contribution to the generation and spread of fire and smoke within and beyond a small room of origin. The ISO 9705 small room test18 was used as a reference scenario for validation of the small and intermediate scale EN tests specified for Euroclassification.
Research projects under the name RADAR were initiated to assist the DETR (now DTLR) to prepare the European supplement for Approved Document B and to bring together the wide experience of UK Official Fire Testing Laboratories with the experience of the building industry. The objective was to ensure that no significant change to the regulatory status quo would occur due to the introduction of the new reaction to fire tests and to the new Euroclass systems.
The essential objective of the experimental programmes was to test a representative range of building and roofing products to both the UK and European reaction to fire test methods. This back-to-back testing was necessary so that differences between the methods could be determined accurately.
Industry partners had to define carefully how their products were installed in buildings and the testing laboratories then performed the tests under similar end-use conditions. This requirement ensured that end-use variables such as type of substrate, presence or not of an air-gap, type and application of adhesive, type and position of joints, etc. were addressed by both the industry partner and the testing laboratory.
Analysis of the RADAR results obtained for cellular plastics shows that there is no overall correlation between the Euroclass system and the UK system. For plasterboard and steel faced products, there was a good correlation with Euroclass B corresponding with UK Class 0. This correlation between Euroclass B and Class 0 was confirmed also for a variety of non-insulation products. There were some significant discrepancies; e. g. aluminium foil faced PIR and PF foams give Class 0 in the UK system but they only gave Euroclasses D and C respectively due to early penetration of the Al foil by the 30kW flame in the SBI test and resulting high FIGRA values. Some thermoplastic products (such as XPS) are unclassifiable in the BS 476 Part 7 test due to their melting behaviour during the first minute of the test.
Moreover, the fire performance of some unfaced cellular plastics (especially thermoplastic types) can be dependent on the thickness of the product. Hence, the results shown in Tables 1 and 2 should not be assumed to apply across a wide thickness range for all insulation products. The fire performance of char-forming polymers is less dependent on thickness; for example, PIR block foam retained its Euroclass C-s2, d0 classification over a thickness range of 12.5mm to 60mm.
As a result, based on further research, the DTLR has now proposed a transposition table for reaction to fire performance. It should be noted that the Euroclasses in Table 3 only refer to fire growth. When the new Euroclass system is introduced, manufacturers will also have to declare the smoke and flaming drop classifications, even though there are no requirements for these parameters in the UK Building Regulations. But even this transposition process is not simple for all building products since the classifications depend on certain key factors; for example:
- There is a fundamental difference in the UK and EC testing systems, especially the use of overall flame spread for UK classification compared to rate of heat release during the early stages of flame attack in the SBI test for Euroclassification.
- Mounting and fixing arrangements, especially the presence or not of air-gaps, position and type of joints, substrate, etc.
- Efficiency of protective facings and coatings to limit the thermal contribution of the core material.
Peter Briggs is at Warrington Fire Research Centre”
Peter Briggs remains the Business Development Manager at Warringtonfire according to LinkedIn, at least.
https://www.dhirubhai.net/in/peter-briggs-887350b/
The British Rigid Urethane Foam Manufacturers Association was founded in 1967 and incorporated as a Limited Company by Guarantee in 1978. BRUFMA became the Insulation Manufacturers Association in November 2017.
https://insulationmanufacturers.org.uk/about/
It therefore appears that a Reference for the RADAR 2 Project Part 1 Report is:
DETR Ref: 39/3/571 cc1848, RADAR 2 Project – Correlation of UK Reaction to Fire Classes for Building Products with Euroclasses and Guidance on Revision of Approved Document B. Part 1: UK and European test data and comparisons between classification systems, WARRES No. 108954, Warrington Fire Research Centre Ltd., Warrington, 2000.
The RADAR Reports and even the BRAC working party meeting minutes may show that Government were made aware by Warrington Fire Research, before publication of Approved Document Part B Volume 2 (2006), that Class 0 (National) to Paragraph 13b. was not Class B (European) as Diagram 40 suggested, and was not ONLY Limited Combustibility as Paragraph 13a. stated, and some academics imagined.
https://www.dhirubhai.net/pulse/textbook-technical-travesty-ian-abley/
But look closely at what Peter Briggs says at the end of the AJ Article. “This transposition process is not simple for all building products since the classifications depend on certain key factors”, for example:
Warrington Fire Research had been awarding Class 0 to Cladding, including Reynobond Aluminium Composite Materials with 100% Polyethylene cores in 1997. Barbara Lane of Arup Fire has the pertinent WARRES Reports in her Phase 1 evidence:
- Reynobond 160PE - Warrington Fire Research WARRES No. 70708 - 14 March 1997 [BS 476-6] BL-ARC00000355
- Reynobond 160PE - Warrington Fire Research WARRES No. 70707 - 14 March 1997 [BS 476-7] BL-ARC00000356
- Reynobond 160PE - Warrington Fire Research Summary of 70707 and 70708 - 9 May 1997 [Class 0] BL-ARC00000357
As RADAR shows Warrington Fire Research were obviously recognised by Nick Raynsford’s Ministry as specialists in the transposition of BS 476 testing with the tests in the BS EN 13501 classification series. Notably the transposition of BS 476: Part 6 and 7, upon which Class 0 is defined by the Ministry, with Class B-s3,d2 in BS EN 13501-1.
Peter Briggs could easily have been talking about Aluminium “protective facings” over the “core” that allowed BS 476: Part 6 and 7 to be passed to the Class 0 criteria in 1997 at Warrington Fire Research. Among other Claddings. That Class 0 award was only five years before RADAR was delivered to the Ministry, with confidential access granted to their industry consultees. That was six years before the British Board of Agrément, the UK's Leading construction certification body, awarded Reynobond a Certificate for High Rise Cladding in 2008, as BBA certificate 08/4510.
If Warrington Fire Research had fully worked out the ACM problem in 2002 who at the Ministry or among their consultees would also have known?
Were the BBA unaware of the Warrington Fire RADAR Reports?
Were the RADAR Reports available to every Minister since Nick Raynsford?
Which civil servants at the Ministry knew the Warrington Fire RADAR Reports?
Why does Approved Document Part B in Volume 1 and 2 (2019) Appendix B: Performance of materials, products and structures Table B1. persist with the transposition of European Class B-s3,d2 with test criteria in BS 476: Parts 6 and 7?
RADAR appears to have said this simplistic transposition was wrong in 2002.
Why does the Ministry transposition exist in Table B1 after 2019?
Has the Ministry not learned since 14 June 2017, if not perhaps 15 years earlier, that materials and products can achieve the Class 0 criteria for BS 476: Part 6 and 7 testing but achieve Class C or D when tested and classified to BS EN 13501-1?
Has another test authority like the BRE repeated the revealing comparison in the Warrington Fire RADAR Reports?
In 2012 the BRE were clearly in possession of RADAR 2, at least. Heat Release Rates, as revealed to Peter Briggs by 2002 through the “Single Burning Item” test BS EN 13823 cited in BS EN 13501-1, have now been studied again by the BRE for the MHCLG using ISO 13785-1:2002 Reaction to fire tests. Tests for facades. Intermediate scale test. But only to show how combustible ACM with a 100% Polyethylene Core is.
https://www.gov.uk/government/publications/fire-performance-of-cladding-materials-research
Were the BRE unaware of the Warrington Fire RADAR 2 Report before 2012?
Why didn’t any test authority accredited by UKAS publicly explain how Class 0 was not “Limited Combustibility” after the ETRAC Report of 2000, the RADAR Reports of 2002, and the BRE Report about internal decorative linings in 2012?
Why was Class 0 for “linings” applied to the Surfaces of External Walls in 2006 and 2013 updates of the Approved Documents, resulting in Paragraph 13 and Diagram 40?
How much did the members of BRAC or the “Industry Advisory Group” know about combustible Class 0 between 2000 and 2017?
Had Ministers made a political and not a technical decision about Class 0?
The warning from Peter Briggs about the particular use of the Class 0 material or product in a Rainscreen system with “… air-gaps, position and type of joints, substrate, etc.” is significant too. This construction is the bitter experience of Grenfell Tower fire, when Class 0 Cladding was Certified for use without a system test being mandatory.
Why did Nick Raynsford leave his favoured BS 8414 test voluntary?
While the “corporates” were working to Class 0 for Cladding, it appears the keepers of knowledge about Approved Document Part B Fire Safety at the Ministry were economical with the truth, without fully backing a system test regime with technical veracity.
When will a Minister in office, or their Shadow in opposition, admit the truth about RADAR and Class 0?
An admission with a publication of the RADAR Reports would help resolve the EWS1. External Wall Fire Review mess that RICS, The Building Societies Association and UK Finance preside over. If combustible Class 0 were the consequence of a political decision, the taxpayer will have to pay. The taxpayer will probably be paying something like £30,000,000,000 anyway, so why leave Leaseholders and Tenants in doubt and debt?
Not having done anything about combustible Class 0 in the past is bad enough, when the state kept the knowledge to themselves and their appointed consultees.
Refusal to tell the truth about RADAR would also be the political work of official Knaves.
Fa?ade Cavity Protection System designer retrospectively fitted protection for existing Fa?ade provisions. THE ONE SOLUTION TO THE CLADDING CRISIS. Smoke Control Consultant Surveyor Engineered solutions
4 年Tell please me WHY! after the loss of life at grenfell we continue to debate the string of failings that led to the the disaster. We have learnt nothing! we are installing not class 0 "ZERO RATED" Aperture closers. I see them everywhere WHY?
Pronouns: He answers to 'Hi' or any loud cry.
4 年This is a very fine, well researched and persuasive piece of work which deserves the widest circulation to Parliament.
Associate Director Fire and Life Safety
4 年Let’s just hope they’re helping the Police with their enquiries
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4 年The basic problem is the same with Euro Class B, which PE ACM sometimes achieved.
Technical Designer
4 年Class 0 Quiz. Which were true while Class 0 existed? A. That Class 0 was EITHER "Limited Combustibility" as Table A7 of Approved Document Part B Volume 2 (2013) in Paragraph 13a., OR tested to BS 476: Part 6 and 7 Criteria in Paragraph 13b. of Appendix A. B. That testing to BS 476: Part 6 and 7 Criteria in Paragraph 13b. allowed combustible materials onto the market. C. That 13b. to BS 476: Part 6 and 7 was not an equivalent Reaction to Fire to 13a. as Limited Combustibility. D. That Paragraph 13 in Appendix A of Approved Document Part B Volume 2 (2013) as the only definition of Class 0 made it appear that 13a. was equivalent to 13b. E. That the Ministry published the Approved Document under statutory powers in Section 6 of the 1984 Building Act, and was responsible for the definition of Class 0. F. That the Ministry published no correction to their Approved Document stating Class 0 was unequal to Limited Combustibility because undermined by Paragraph 13b. tests, even when warned by a Select Committee in 1999 and the Warrington Fire Research RADAR Reports of 2002. All six... Construction professionals may have known A. but have been ignorant of B., not expected C., did not question D., remained trusting of the Ministry in E., and were never corrected through F. Table B1 Reaction to Fire Classifications: transposition to national class in Appendix B: Performance of materials, products and structures of Approved Document Part B - Fire Safety, Volumes 1 and 2, maintains the previous Paragraph 13b. Class 0 criteria to BS 476: Part 6 and 7 and transposes them to BS EN 13501-1 Class B-s3,d2. When Class C and D can be obtained by materials and products that meet both of the following: a. Class 1 in accordance with BS 476-7. b. Has a fire propagation index (I) of a maximum of 12 and sub-index (i1) of a maximum of 6, determined by using the method given in BS 476-6. Index of performance (I) relates to the overall test performance, whereas sub-index (i1) is derived from the first three minutes of the test. Hence the Note in Table B1: "The national classifications do not automatically equate with the transposed classifications in the ‘BS EN 13501-1 classification’ column, therefore products cannot typically assume a European class unless they have been tested accordingly."