Chapter 48: The legislative background

¶48.1 Chapter 5 of the Phase 1 report contains a brief summary of the main legislative provisions and associated guidance that applied to the refurbishment of Grenfell Tower. However, in order to give a true picture of the context in which important decisions were taken in connection with the work, it is necessary at this stage to describe those provisions more fully and in greater detail. Given the important role played by the cladding system in the fire at Grenfell Tower, we concentrate on the statutory framework, including the statutory guidance relating to the construction of external walls, applicable during the period in which the refurbishment was carried out. In this chapter we also examine briefly the regulatory framework governing building control and the duties applicable under the CDM Regulations.

The Building Act 1984

¶48.2 The Building Act 1984 ("the Act")¹¹ The Building Act 1984 {HOM00035068}. is the principal primary legislation governing building and buildings and related matters. Section 1(1) of the Act gives the Secretary of State the power to make regulations with respect (among other things) to the design and construction of buildings for a number of purposes, including securing the health, safety and welfare of persons in or about buildings. Regulations made under section 1(1) of the Act are known as "building regulations" and were made by way of statutory instrument. The regulations in force at the time of the refurbishment were the Building Regulations 2010 ("the Regulations").²² The Building Regulations 2010 {INQ00015098}.

¶48.3 Section 6 of the Act provides that the Secretary of State, or a designated body, may approve and issue documents for the purpose of providing practical guidance with respect to the requirements of any provision of the Regulations. At the time of the refurbishment that practical guidance was contained in a series of Approved Documents. The provisions of the Approved Documents are not mandatory; their purpose is merely to describe one or more ways in which the requirements of the Regulations can be met. Failure to comply with an Approved Document does not in itself render a person liable to any civil or criminal proceedings, but it may be relied upon in any proceedings as "tending to establish liability". Likewise, compliance with the provisions of an Approved Document, although not proof of compliance with the Regulations, may be relied on in any proceedings as "tending to negative liability".³³ See Section 7 of the Building Act 1984 {HOM00035068/13}. It is important to note, however, that compliance with the Approved Documents does not ensure compliance with the Regulations.

¶48.4 Schedule 1 of the Act sets out further matters which building regulations may provide for. Paragraph 7 of Schedule 1 provides that they may make provision for (among other things) fire precautions.⁴⁴ Paragraph 7(iv) of Schedule 1 of the Building Act 1984 {HOM00035068/109} states "Fire precautions including (a) structural measures to resist the outbreak and spread of fire and to mitigate its effects, (b) services, fittings and equipment designed to mitigate the effects of fire or to facilitate fire-fighting, and (c) means of escape in case of fire and means for securing that such means of escape can be safely and effectively used at all material times."Show full note

¶48.5 Part 3 of the Regulations contains requirements for local authorities to be notified of building work. In particular, regulation 12(3) obliges a person intending to carry out building work in relation to a building to which the Regulatory Reform (Fire Safety) Order 2005 (the Fire Safety Order) applies to deposit full plans with the local authority in accordance with regulation 14. (The refurbishment of Grenfell Tower involved work on a building to which the Fire Safety Order applied and a deposit of full plans was therefore required.) By virtue of regulation 14, full plans are to consist of a description of the proposed work together with plans describing the work and demonstrating that it would comply with the Regulations.

¶48.6 The Act itself provides for the local authority's response to the deposit of full plans. Section 16 provides that, where plans for proposed work are deposited with a local authority, it is their duty to pass the plans unless a provision elsewhere in the Act requires them to be refused, or the plans are defective, or they show that the proposed work would contravene any of the Regulations. If the plans are defective or show that the work would contravene the Regulations, the local authority may reject them or (with the consent of the person by whom they were deposited) pass them subject to conditions. Within 5 weeks from the deposit of plans the local authority must give notice to the depositor stating whether they have been passed or rejected.⁵⁵ Section 16(4) of the Building Act 1984 {HOM00035068/20}. The five-week limit is subject to any agreed extensions up to a maximum of two months (section 16(12) {HOM00035068/22-23}.

¶48.7 Failure to comply with the Regulations is punishable by a fine (section 35), but in addition local authorities have the power to require the owner of the building to pull down or remove any work that contravenes the Regulations or make such alterations to it as are necessary to make it comply with them (section 36).

The Building Regulations 2010

¶48.8 The Regulations prescribe the standards that building work must meet and impose on the person proposing to carry it out a requirement to obtain approval from a local authority or approved inspector. The requirements for building work are set out in regulation 4, which provides that building work shall be carried out so that it complies with the requirements contained in Schedule 1. The Regulations apply to building work as defined in regulation 3, which includes, among other things, the material alteration of an existing building. An alteration is material for these purposes if the work, or any part of it, would at any stage result in the building's ceasing to comply with any one of a number of listed requirements of the Regulations or (if it did not comply with such a requirement before the work commenced) becoming more unsatisfactory than it previously had been, but there is no requirement when work is done to an existing building to bring it up to current standards. This is sometimes known as the "non-worsening principle". The listed requirements include functional requirements B1, B3, B4 and B5 relating to fire safety.⁶⁶ Section 3(3) of the Building Regulations 2010 {INQ00015098/7}. It is not disputed that the cladding work to Grenfell Tower, including the addition of insulation, and the renovation of the smoke control system constituted material alterations and that the Regulations therefore applied to them.

¶48.9 Paragraph 8(1)(e) of Schedule 1 to the Act gives the Secretary of State power to make building regulations with respect to buildings that are subject to a material change of use. A material change of use is defined in regulation 5. It occurs when, among other things, a building which contains dwellings is altered to contain a greater or lesser number of dwellings than it did previously. In the case of Grenfell Tower refurbishment, the addition of new flats in those parts of the building that had previously been put to other uses constituted a material change of use.

¶48.10 The prescribed standards for building work are expressed in schedule 1 to the Regulations in terms of functional requirements. Although the refurbishment was required to comply with all the requirements, for the purposes of this report we concentrate on Part B.

¶48.11 Part B is concerned with fire safety and is divided into five sections: B1 Means of warning and escape. B2 Internal fire spread (linings). B3 Internal fire spread (structure). B4 External fire spread. B5 Access and facilities for the fire service.

¶48.12 Requirements B1, B3(4) and B4 are of particular relevance to the fire at Grenfell Tower and deserve to be quoted in full:

Means of warning and escape

¶B1. The building shall be designed and constructed so that there are appropriate

provisions for the early warning of fire, and appropriate means of escape in case of fire from the building to a place of safety outside the building capable of being safely and effectively used at all material times.

Internal fire spread (structure)

¶B3. (4) The building shall be designed and constructed so that the unseen spread of fire and smoke within concealed spaces in its structure and fabric is inhibited.

External fire spread

¶B4. (1) The external walls of the building shall adequately resist the spread of fire over the

walls and from one building to another, having regard to the height, use and position of the building.

¶(2) The roof of the building shall adequately resist the spread of fire over the roof and from one building to another, having regard to the use and position of the building.

¶48.13 The Regulations also contain certain energy efficiency requirements. In particular, regulation 23 provides that where renovation of a thermal element (which would include an external wall) constitutes a major renovation or amounts to the renovation of more than 50% of the element's surface area, the renovation must be carried out so as to comply with paragraph L1(a) of schedule 1 in so far as that is technically, functionally and economically feasible. Requirement L of schedule 1 is headed "Conservation of Fuel and Power" and paragraph L1(a) provides that reasonable provision shall be made for the conservation of fuel and power in buildings by limiting heat gains and losses through thermal elements and other parts of the building fabric.

¶48.14 The supervision of the proposed work by the local authority is intended to culminate in the issue of a completion certificate evidencing compliance with certain requirements of the Regulations. Those requirements include the applicable requirements of regulation 38 (discussed below) and schedule 1 of the Regulations. Once issued, a certificate is evidence (but not conclusive evidence) that the requirements specified in the certificate have been complied with.

¶48.15 Regulation 38 is concerned with the provision of fire safety information. It applies where building work consists of or includes the erection or extension of a relevant building or is carried out in connection with a relevant change of use and when Part B of Schedule 1 imposes a requirement in relation to the work. In those circumstances the regulation obliges the person carrying out the work to give the responsible person under the Fire Safety Order not later than the date of completion of the work or the date of occupation of the building or extension, whichever is the earlier, information relating to the design and construction of the building and the services, fittings and equipment provided in or in connection with it that will assist that person to operate and maintain the building with reasonable safety.

¶48.16 The Fire Safety Order is considered in greater detail in Part 2 of this report. For the purposes of the Regulations, however, it is important to note that article 45 requires a local authority in receipt of a full plans application in relation to a building to which the order applies to consult the enforcing authority (in this case the London Fire and Emergency Planning Authority ("LFEPA") before passing the plans.⁷⁷ For more detailed consideration of this provision see Menzies Module 1 Report {BMER0000004/139-140}. In practice, save for the highest risk or most complex projects, the consultation expected by building control and the LFEPA related to the B1 (means of escape) and B5 (access and facilities for the fire service) functional requirements only.

The Construction (Design and Management) Regulations 2007 and 2015

¶48.17 The Construction (Design and Management) Regulations were made by the Secretary of State under powers in the Health and Safety at Work Act 1974. They seek to protect persons against risks to health and safety arising from construction work through the establishment of a systematic framework for the assessment and management of those risks. The definition of construction work includes the construction, alteration, conversion, fitting out, commissioning, renovation, repair, upkeep, redecoration or other maintenance of any building.⁸⁸ See regulations 2 and 3 of the Construction (Design and Management) Regulations 2007 {INQ00011315/1-4}. The first regulations were made in 1994 and came into force in March 1995. They were replaced in 2007 and again 2015. The 2007 Regulations remained in force until 5 April 2015 when the 2015 Regulations came into force.

¶48.18 The CDM Regulations 1994 and 2007 were each supported by guidance in the form of Approved Codes of Practice (ACOPs) published by the Health and Safety Executive, which provided practical guidance on how to comply with the law.⁹⁹ See the 2007 Code "Managing health and safety in construction" at {INQ00013936}. The CDM Regulations 2015 {INQ00011316} were not supported by an ACOP. Instead, the HSE published guidance in the form of a document entitled "Managing health and safety in construction" {HSE00000003}.

¶48.19 When the CDM Regulations 2007 were superseded by the CDM Regulations 2015, a transition period from 6 April to 6 October 2015 was introduced to enable all those affected to put in place alternative arrangements.

¶48.20 The CDM Regulations 2007 are relevant to our investigation of the refurbishment because they imposed various duties on clients, designers (defined as including anyone preparing or modifying a design or instructing others to do so)¹⁰¹⁰ See Regulation 2 of the 2007 Regulations {INQ00011315/2}. and contractors relating to health and safety or reinforced existing duties under health and safety legislation. We refer to these in more detail where relevant in the following chapters describing the refurbishment work at Grenfell Tower. The 2015 Regulations also imposed an obligation on the principal designer to prepare a health and safety file, keep it under review and deliver it to the client at the end of the project.¹¹¹¹ Regulations 12(5) and 12(10) of the 2015 Regulations {INQ00011316/12}.

Statutory guidance: Approved Documents

¶48.21 As we have set out above, section 6 of the Building Act 1984 Act provides for the publication by the Secretary of State of documents providing practical guidance with respect to the requirements of the Building Regulations. At the time of the refurbishment that practical guidance was contained in a series of Approved Documents, which themselves referred to British Standards and other guidance.

Approved Document B

¶dealt with fire safety. Before the Grenfell Tower fire, it was divided into two volumes: volume 1 dealt with dwelling houses; volume 2 dealt with all other buildings, including blocks of flats and buildings containing flats.

¶Approved Document B

¶48.22 As we have set out in Chapters 4 and 6, Approved Document B was first published in 1985 and was amended on numerous occasions thereafter. In this section of the report we have referred to the 2006 version incorporating the 2007, 2010 and 2013 amendments.¹²¹² {CLG00000224}.

¶48.23 Section 12 of Approved Document B provided guidance on the construction of external walls.¹³¹³ {CLG00000224/95}. Our attention has focused most closely on paragraphs 12.5–12.8 of that guidance, which are worth setting out in full:

"12.5 The external envelope of a building should not provide a medium for fire spread if it is likely to be a risk to health or safety. The use of combustible materials in the cladding system and extensive cavities may present such a risk in tall buildings. External walls should either meet the guidance given in paragraphs 12.6 to 12.9 or meet the performance criteria given in the BRE Report Fire performance of external thermal insulation for walls of multi storey buildings (BR 135) for cladding systems using full scale test data from BS 8414-1:2002 or BS 8414-2:2005. 12.6 The external surfaces of walls should meet the provisions in Diagram 40… 12.7 In a building with a storey 18m or more above ground level any insulation product, filler material (not including gaskets, sealants and similar) etc. used in the external wall construction should be of limited combustibility (see Appendix A). This restriction does not apply to masonry cavity wall construction which complies with Diagram 34 in Section 9.¹⁴¹⁴ {CLG00000224/95-96}. 12.8 Cavity barriers should be provided in accordance with Section 9."

¶48.24 Paragraph 12.5 thus provided two potential routes to compliance with the Regulations: following the guidance in paragraphs 12.6 to 12.9 (sometimes referred to as the "linear route") or meeting the performance criteria in BR 135 following testing in accordance with BS 8414. However, Approved Document B provided no more than guidance and in addition to the two routes it set out, there could be other ways of demonstrating compliance with the functional requirements of the Regulations to which we refer below. We note in passing that the majority of witnesses who gave evidence about the design of the Grenfell Tower refurbishment either thought that the "linear route" had been adopted or were not aware which route had been adopted.¹⁵¹⁵ Sounes {Day7/138:2-16}; Crawford {Day9/177:3}-{Day179:23}; Ashton {Day17/138:2-3}; Lawrence {Day22/77:1-16}; Bailey {Day33/27:10-24}; Anketell-Jones {Day35/170:21}-{Day172:25}; Anketell-Jones {Day35/173:15-19}; Lamb {Day37/141:19}-{Day37/142:14}; Hoban {Day45/37:21}-{Day45/40:16}; Allen {Day47/25:22-25} {Day47/116:22-25}.

¶48.25 Paragraph 12.6 of Approved Document B provided that the external surfaces of walls should meet the provisions in Diagram 40.¹⁶¹⁶ {CLG00000224/95-97}.

¶Figure 48.1 – Diagram 40

¶48.26 The heading of Diagram 40 (in particular the use of the words "or walls") might suggest that a distinction is being drawn between "external surfaces" and "walls" but the label in the key to Diagram 40 is concerned solely with "external wall surface classification". We think it is clear that it was intended to apply to the wall's external surface and thus to the material or product that makes up the outer surface of the wall.¹⁷¹⁷ Hyett {PHYR0000029/34} section 4.2.42. That is certainly consistent with the language of paragraph 12.6 of the guidance which introduces Diagram 40 and which refers to the "external surfaces of walls".

¶48.27 Diagram 40e applied to Grenfell Tower and required that above 18 metres from the ground the external surface of the walls had to satisfy national class 0 or European class B-s3, d2 or better. We have described in Chapter 5 the tests which supported those classifications.

¶48.28 In our view the wording of paragraph 12.6 suggests that it applies to the external surface of a wall and does not include any product, such as insulation, that may have been fitted behind it. Similarly, when considering a composite product, such as an ACM panel, the paragraph naturally refers to its surface rather than to its core.

¶48.29 Paragraph 12.7 is headed "Insulation Materials/Products". It provided that in a building with a storey 18 metres or more above ground level any insulation used in the external wall construction should be of limited combustibility.¹⁸¹⁸ Throughout the external wall, not just at heights above 18 metres. Limited combustibility is defined in Appendix A of Approved Document B (see Chapter 6).¹⁹¹⁹ {CLG00000224/132}.

¶48.30 It has been argued that paragraph 12.7 should be understood as applying to the core of ACM cladding panels of the kind installed at Grenfell Tower.²⁰²⁰ Team 1 Module 1 Opening Statement {BSR00000061/30} paragraph 13.16(2). The argument was put in two ways. The first relied on the use of the word "filler" in paragraph 12.7, which was said to be apt to refer to the core of a composite cladding panel. We do not agree with that. The word "filler" forms part of the expression "insulation product, filler material (not including gaskets, sealants and similar) etc. used in the external wall construction". In that context the word "filler" naturally means a material, such as compressible fibre or expanding foam, used to fill gaps of an unplanned or occasional kind rather than small apertures that are intended to be closed off by gaskets or sealants. It is not apt to refer to the core of a composite cladding panel which is an integral part of the finished product. We derive further support for our conclusion from the fact that we have not seen any evidence that the core of a composite panel was described as "filler" by anyone in the building industry before the Grenfell Tower fire.

¶48.31 The second argument was that the provisions relating to external surfaces in paragraph 12.6 and Diagram 40 were additional to the basic requirement that the external walls of a building over 18 metres in height should be composed only of materials of limited combustibility in the facade and do not override the functional requirement that they adequately resist the spread of fire.²¹²¹ BSR Team 1 Module 1 Opening Submissions {BSR00000061/30} paragraph 13.16 (2). That interpretation was supported by Beryl Menzies²²²² Menzies {BMER0000004/126} paragraph 417. and support can also be found for it in industry guidance published by the Building Control Alliance in its Technical Guidance Note 18, which we discuss in Chapter 49.²³²³ BCA Technical Guidance Note 18, Issue 0 {CEP00057294}. However, in neither case was any reason given for adopting that interpretation, beyond saying that it would give effect to functional requirement B4(1).

¶48.32 We do not agree that paragraph 12.7 of Approved Document B can be read in that way. Functional requirement B4(1) sets out the standard with which external walls must comply. The purpose of Approved Document B was to provide guidance on ways in which that standard might be met, which it did by identifying certain elements of the wall and suggesting the kinds of materials that were likely to ensure compliance. There is nothing in the language of paragraphs 12.5–12.9 (including paragraph 12.7) to support the conclusion that all elements of the external wall, including the core of any composite panel, should be of limited combustibility. The only reference to "limited combustibility" is found in paragraph 12.7 which referred only to insulation products. That would naturally have been understood as referring to materials and products used for the purposes of insulation, not as referring to materials chosen for other purposes but which happen to have insulating properties.

¶48.33 Section 9 of Approved Document B provided guidance on the provision of cavity barriers to inhibit the spread of smoke and flame through concealed spaces or cavities in the construction of a building as required by functional requirement B3.²⁴²⁴ {CLG00000224/82}. Paragraph 9.1 draws attention to the risks of fire spread within cavities and warns that "as any spread is concealed, it presents a greater danger than would a more obvious weakness in the fabric of the building."²⁵²⁵ {CLG00000224/82}. Paragraph 9.3 makes it clear that cavity barriers should be provided to close the edges of cavities, "including around openings". Diagram 33 (reproduced below) shows where cavity barriers are required in external walls, namely, at the lines of compartment floors and compartment walls, at the top of any cavities in the walls and around openings such as those provided for doors and windows.

¶Figure 48.2 – Diagram 33

¶48.34 Paragraph 9.13 gives guidance on the construction and fitting of cavity barriers and states that they should provide at least 30 minutes' fire resistance.²⁶²⁶ {CLG00000224/86}. Cavity barriers should be distinguished from fire stopping, which is a seal provided to close an imperfection of fit or design tolerance between elements or components, to restrict the passage of fire and smoke.²⁷²⁷ Approved Document B, Appendix E, definition of "Fire stop" {CLG00000224/144}.

Comments on Approved Document B

¶48.35 Our investigations have revealed two particular problems relating to Approved Document B to which we think we should draw attention. The first relates to the guidance itself. Paragraph 2.3c on the means of escape from flats assumes that compliance with functional requirement B3 will provide a high degree of compartmentation and a low probability of fire spreading beyond the flat of origin, so that simultaneous evacuation of the building is unlikely to be necessary. In other words, it assumes that there would be no need for a partial or total evacuation of the building in the unlikely event that the fire spread beyond the compartment of origin and that a stay put strategy is therefore appropriate. That assumption holds good, however, only as long as the external wall of the building does not itself support the spread of fire.

¶48.36 Some uncertainty has arisen from the fact that functional requirement B4(1), which section 12 of Approved Document B was intended to support, requires only that the external walls should "adequately" resist the spread of fire, having regard to the height, use and position of the building. However, we assume that the word "adequately" was chosen to accommodate the full range of buildings to which the functional requirement applies. What is adequate will vary from case to case having regard to a number of matters, including the characteristics of the building.

¶48.37 It has been known for a long time that, even in the case of a fully compartmented residential building constructed entirely of non-combustible materials such as concrete (as Grenfell Tower was before the refurbishment), a fire in one compartment may spread to the compartment above as a result of the "coanda" effect. A limited degree of fire spread of that kind is not considered to undermine a stay put strategy because the extent of the evacuation required is very limited. Thus a limited degree of fire spread is acceptable, even where the building has a stay put strategy, because the ability of the external walls to resist the spread of fire is adequate.

¶48.38 However, the assumption underlying the guidance ceased to hold good when it became the practice to overclad high-rise residential buildings using materials that would support the spread of fire and to construct new buildings with steel frames with external walls composed in whole or in part of materials that would support the spread of fire. Unless all the materials used in the external wall are non-combustible, the effect in either case is to destroy the isolation of individual compartments by installing a continuous layer of combustible material on the outside of the building that would support the spread of fire across the outside of many compartments.

¶48.39 The failure to appreciate the effect of those developments introduced a fundamental flaw into the statutory guidance, which was not amended to draw the attention of designers to the need to consider the nature of the materials proposed to be used and other factors, such as access for the fire and rescue service, the nature of the occupants, the measures provided for alerting them to a fire and the means of escape if that should that become necessary, all of which have a bearing on whether the ability of the external wall to resist the spread of fire is adequate. If the external walls of a high-rise residential building support the spread of fire to any significant degree they are unlikely adequately to resist the spread of fire unless arrangements have been made to enable all those occupants who may be threatened by the fire to escape quickly and safely; but in any event it is not possible to operate a stay put strategy safely in relation to such a building.

¶48.40 The effect of the introduction of new materials and methods of construction does not appear to have been recognised by any of the witnesses (other than the experts), including those from DCLG or BRE.²⁸²⁸ See the examination of Dr Colwell at {Day231/175:11-24}; Debbie Smith {Day236/114:4}-{Day236/115:4}; Martin {Day251/96:19}-{Day251/98:19}; Burd {Day238/214:10}-{Day238/215:6}. There appears to have been a widely held view in the construction industry that if the surface of an external wall panel was classified Class 0, it was safe to use it on a building of any kind. There was also a widespread but erroneous understanding that if, following a test in accordance with BS 8414, an external wall system satisfied the criteria in BR 135, the building when completed would inevitably satisfy functional requirement B4(1) of the Building Regulations. Moreover, many in the industry failed to appreciate that the BS 8414 test applies only to a wall system as a whole and tells one nothing about its individual components. It is a matter of concern that no one appears to have considered whether the extent of flame spread that could occur while still satisfying the performance criteria in BR 135 was consistent with the adoption of a stay put strategy. We return to this matter in the context of our recommendations.

¶48.41 The second problem relates to the relationship between the regulations and the statutory guidance and the way in which Approved Document B is understood and applied by many in the construction industry. One striking feature of the evidence was the extent to which many construction professionals have routinely regarded the statutory guidance as containing a definitive statement of the requirements of the Building Regulations. In the absence of a clear statement to the contrary, we think that is an inevitable consequence of couching the guidance in prescriptive terms. Many construction professionals appear to be uncomfortable with the broad language of functional requirements B1 to B4 and want to be told what is expected of them and in any event many are not competent to translate the general language of the functional requirements into decisions about the choice of materials or methods of construction. That presents a particular problem for those who frame the statutory guidance, but while the functional requirements continue to set the standard which the law requires, it must be made clear in the guidance that following its provisions will not necessarily result in compliance with the regulations.

¶48.42 For reasons given elsewhere, Class 0 was never an appropriate standard for rainscreen panels, particularly panels with highly combustible polyethylene cores. In our view the guidance should explicitly have drawn the attention of those responsible for designing the cladding to the fact that Class 0 panels might not satisfy the requirements of functional requirement B4(1).

¶48.43 More generally, we think that Approved Document B requires a complete overhaul. It is out of date in many respects, not helpfully worded and does not contain the guidance that designers need. In a constantly changing environment it needs to be kept under review and revised annually or more often if circumstances demand. It should be drafted conservatively, so that those who follow the guidance can have a high degree of confidence that, if it is followed, the functional requirements will be met. Again, we return to this matter in the context of our recommendations.