Over the last ten years a number of reports have been published addressing gas contaminated-land, many of them the result of research by the Building Research Establishment (BRE) and the Construction Industry Research and Information Association (CIRIA). This latest publication is timely in providing guidance on the topic applied to housing given the Government priority for development of brownfield sites. While the Government has set a target for 60% of new housing to be on brownfield sites, local authorities have new duties under Part IIA of the Environmental Protection Act to identify ‘Contaminated Land’.
Clearly, not all brownfield sites are contaminated, and the presence of hazardous soil gases is not only confined to brownfield sites. However, methane and carbon dioxide produced from biodegrading material are often found on brownfield sites, and if the Government's target is to be achieved, the use of protective measures is set to increase. Building Regulations require the protection of building occupants from the effects of gaseous contaminants, and hence this publication will be of interest to local authorities as regulators, as well as obviously to developers and designers.
The protective measures described in this publication make use of barriers in the ground slab and sub-floor venting. Detailing is important to ensure that the principles of the protective measures are not compromised in construction or through poor detailing, especially with regard to incoming services pipes and ducts. This is where this publication scores its mark. It considers the principles of construction and addresses gas entry routes and then provides fully illustrated guidance for installation of the protective measures. New housing, extensions and remedial measures in existing buildings are addressed in turn. Specific details are then provided for gas-resistant membranes, venting layers, granular blankets, gas drains and service entries. For each detail, illustrations are accompanied by descriptions and a checklist of ‘watchpoints’. There is necessarily much repetition, as each situation considered has its own illustration, construction details and checklist. However, this makes for a reference which is easy to use, clearly not intended for reading from start to finish.
The document does not address the investigation and assessment of gas contamination for which specialist guidance is recommended. Nor does it provide guidance for the design of specific gas control systems. It focuses on the practical details while making reference to complementary guidance, including previous BRE reports BR211, ‘Radon: guidance on protective measures for new buildings’ and BR212, ‘Construction of new buildings on gas-contaminated land’ and the CIRIA series of guidance reports (Reports 130, 131, 149, 150, 151 and 152). For the specialist reader, it is worth noting here that one of the publications referred to, the DETR/Arup Partners in Technology design guide ‘Passive venting of soil gases beneath buildings’ can now be freely downloaded from the web site www.arup.com/environmental/. Active protective measures are not addressed, since they require specialist assessment and design, as well as specialist construction and maintenance.
This publication has received the support of the Environment Agency which has provided funding and contributed to the content. The presence of the Environment Agency logo on the front cover next to that of the BRE will ensure that the publication is recognised as authoritative and adopted by regulators and construction professionals, ensuring best practice for gas protective measures.
This book showcases the contemporary use of visual, predominantly in situ, concrete across Europe. Through 22 projects it demonstrates how concrete can be used in soft organic, highly finished or raw and brutal form to achieve the required architecture. For each project the concept of the design is discussed, along with the construction techniques used and the views of the designers and the contractors. For those with experience of trying to produce high-quality in situ concrete, reading between the lines can give a good insight into what went well and where problems occurred. Often it is apparent that the designer did not get what he intended; in some cases he has none the less been happy with the finish, in others less so. Similarly there are discussions by contractors on the level of information that they tendered against, compared to that finally requested by the design team.
The introduction talks of the difficulties in achieving high-quality visual concrete and then describes the measures, almost in specification form, required if it is to be attempted. It will soon dawn on the reader that specifying all the measures described would break both the budget and programme of most projects. Unfortunately there is no recognition here that there are various levels of requirements for various types of visual concrete. For example, individual columns may not require the same rigour as a large in situ façade simply because comparison between pours is less obvious. If the reader is not put off by the bad news he will then be inspired by the examples. I would have preferred the bad news at the end after I had decided that visual concrete was the way forward!
Of the 22 projects discussed, the author asks which will be seen as influential by future generations. It is hard to pick specific projects due to the range of both structures and the way that the concrete is used. The projects mentioned here are chosen to demonstrate the breadth of structures covered in the publication rather than any order of merit.
For in situ concrete of the highest quality the Crematorium at Baumschulenweg, Berlin is a fine example both externally and internally. Even so, the architect was initially disappointed by the variations in colour due to the curing of columns but grew to like what he described as the ‘marbled effect’. This level of quality can be contrasted with that at the Fuencarral Library where the architect wanted the external walls to rise out of the ground in the same material as that below ground. What he got is just that and the colour variation and markings of the façade are very similar to that seen on large basement walls. We are told this is what the architect wanted—a ‘rough cast, brutal finish’. The overall effect is, however, stunning and yet I doubt many UK clients could be persuaded that the level of concrete finish was acceptable. Other unusual finishes include the use of coloured sprayed concrete to cover the whole of the façade of the Minnaert Building at Utrecht University, and the ‘brutal, raw and ugly’ finish of the Memorial of the Synagogue, Wuppertal.
The range of structures considered extends from the large American Air Museum at Duxford (although predominantly precast) to the Belderbos House in Arstene where in situ concrete was the material chosen to internally transform an old industrial building to make a house.
I think the book is a good starting point for engineers who are discussing with an architect or client the option of using exposed concrete. The images show that the results can be stunning and yet there is enough detail in the text to see the extent of control that was required and to understand where things went wrong. It is certainly clear that the results were often not what the design team had set out to achieve. It will be interesting to see whether the images can persuade UK clients and architects that it is not necessary to achieve the near-impossible blemish-free finish to realise impressive exposed concrete.
Wind engineering is a multidisciplinary subject, one part of which is building aerodynamics. Even so, the subject of building aerodynamics is wide-ranging in scope and must tackle problems associated with both high- and low-speed winds. There are now several books in print which cover the subject of wind engineering. However (despite what they may claim), the intellectual level required to understand them ranges probably somewhere between ‘academic’ and ‘specialist consultant’. For a long time there has been a need for a book that addresses issues encountered by practising engineers (not academics studying engineering) and architects. The stated aim of this book is to fill this need, although in my opinion the material has been pitched at too high an academic level. Furthermore, the questions as to whether to conduct a CFD or a wind tunnel study—which is a real issue that engineers and architects can encounter today—has been avoided, probably to avoid controversy.
This book has been written from the author's experience in the field of experimental small-scale wind tunnel testing, hence the subjects covered are, in the main, amenable to wind tunnel investigation. Many examples are given in the book of tabulated results obtained from different types of study undertaken by the author. However, certain aspects of building aerodynamics (e.g. internal flows, fire studies, low-speed pollution studies, and far-field pollution studies) can not be investigated properly using similar techniques. Although, where appropriate, such limitations are stated clearly, this book may give an impression to an engineer or architect that all problems can be studied by undertaking wind tunnel testing. In reality, the best solution for investigating a problem is to use the most appropriate tool, which may or may not be a wind tunnel test.
Having stated the above, I think that the overall balance of the book is laudable. The book covers more commonly encountered building aerodynamic problems, as well as discussing other less well known (but equally important) issues. As such, the author has had to tread a tightrope between giving justice to each section, bringing out points pertinent to his target audience, and yet keeping the length to an acceptable level. The book contains sensible advice and practical rules of thumb. Even if the mathematical details are incomprehensible to the intended audience, reading the relevant sections would help in asking the right wind-related questions, and would highlight important issues that might not otherwise have been considered.
The book is divided into eleven chapters, and the main elements of the content are as follows.
Chapter 1 discusses the physics of the wind—that is, what causes wind, and important wind-related properties. It also considers atmospheric stability, which is shown to be important with regard to emission studies.
Chapter 2 deals with issues that affect the fundamental wind-flow patterns around buildings.
Chapter 3 considers static, mildly dynamic and dynamic wind loads. It also discusses possible solutions should dynamic instabilities occur.
Chapter 4 considers the wind environment around buildings, and touches upon human response to vibration.
Chapter 5 deals with rain and snow (very briefly)—subjects that receive remarkably little attention in other literature.
Chapter 6 considers ventilation and discusses the topical subject of car park ventilation.
Chapter 7 discusses the general principles of ensuring that fire-generated smoke is controlled safely, but only with regard to any input a wind engineer might have. Having stated this, as shown in this book, that input can be vital.
Chapter 8 considers emissions from buildings, and discusses possible remedial techniques. By its own admission, the text only scratches the surface of a huge subject. Nevertheless, the importance of the efflux velocity upon ground-level concentration is demonstrated, as well as drawing attention to the temporal nature of effluent concentration.
Chapter 9 considers how wind tunnel studies can be used to assess the effect that surrounding buildings have upon inland sailing conditions. An interesting conclusion reached is that buildings should generate higher wind speeds over the water, which is the reverse of the task wind engineers are usually faced with.
Chapter 10 deals briefly with experimental methods used in wind tunnel testing. However, flow visualisation is not covered at all, despite its usefulness in demonstrating flow features to engineers and architects.
Chapter 11 is a brief introduction to the statistics used in the book. A good knowledge of probability theory and integrals is necessary to understand this chapter.
To summarise, I think that this book goes part way to addressing its intended audience of engineers and architects. Moreover, for this particular audience it is the best book on building aerodynamics that I have come across to date. However, whereas the book is concise and well-balanced, I think the academic level has been pitched too high, and the presentation of information and figures leaves room for improvement.
The authors have updated the June 1991 Second Edition in this 2001 publication to include steelwork design according to the latest British Code BS 5950: 2000.
This edition is timely as many British engineers struggle to familiarise themselves with the recent Code revisions. However, the book is not a commentary on BS 5950: 2000, but a comprehensive work of analysis and design application for steel elements and structures. Chapter One deals with loads, material properties and summarises the behaviour of steel structures.
Tension members, compress members, in-plane bending of beams and torsion have a chapter each, while other chapters cover local buckling of plates, lateral buckling of unbraced beams, members subjected to both axial and transverse loads (‘Beam-columns’), frames and connections.
The book is well-written, with relevant glossary of terms, notation and references, plus it includes many useful worked examples. Practising engineers may wonder what ‘Unworked examples’ are, but ‘Questions’ such as these will be familiar to undergraduate and postgraduate students. Unfortunately, the answers are not given, but they should be derivable by those who read the book.
The publication is an excellent ‘state of the art’ and will be of great use to undergraduate and graduate engineering students and by practising structural engineers.
