Right place – right time: leading expert john colvin talks about his life in glass

When John Colvin first joined Pilkington, they had recently invented the Float Glass process. They had the vision that this would revolutionise the use of glass in buildings and decided to dramatically increase their research and development on glass. They employed an Architect, David Button, to run their Environmental Advisory Service, part of the Technical Advisory Service (TAS).

Architectural potential

David Button, who later took over running the whole TAS, knew that glass could be utilised to a much greater extent, but realised that there was very little information available to the architectural profession about how glass could and should be used in buildings. If Pilkington could generate and disseminate this information, the architectural profession would be set free.

It was against this background that John, with a degree in Maths from Cambridge University, took on a job in TAS to investigate the strength of glass and how it performed in buildings.

‘I found glass fascinating. As a mathematician, I was not lumbered with the preconceived ideas about glass of either materials scientists or engineers and there was (and still is) very little published information about building glass. So I started to find out about glass for myself – its huge spread of strength results from nominally identical pieces – the way one can safely put a load on a piece of glass only to see it break minutes, hours or even days later.’

The 70s boom

The 1970’s was certainly the right time to be in Pilkington to learn the basics of how glass works and how it can be used. Float glass was a brand new type of building glass becoming more easily available, but little was known about whether it was the same strength as sheet glass or plate glass. Laminated glass had just started to be used in buildings and there was no information as to how it performed when subject to wind loads.

There was a lot of interest in solar control glass, as a result of all the overheating 1960’s office blocks. Roller hearth toughening ovens were becoming available which meant that toughened glass was more easily available. The 1973 oil crisis led to the dramatic increase in the use of double-glazing.

Setting standards

As a monopoly supplier, Pilkington was the sole source of information in the UK on how glass worked (or didn’t), so they became heavily involved in all aspects of glass applications. For example, all the work to develop the BS 6206 safety glass test standard was undertaken in Pilkington TAS.

John was part of a team of people performing tasks related to how building glass performed, analysing things like wind load resistance, static fatigue, thermal stress, fixing and framing methods, solar control, sound insulation, U values and all the other basic information which has been incorporated in Standards and methods used for building glass in the UK.

After the hectic pace of developing background information in the 1970s, TAS later concentrated more on disseminating information on how to use glass. In its heyday in the early 1990s, the Consultancy Services section of TAS, run by John, was answering around 3000 technical enquiries per month. Some of these were novel uses of glass, which ended up with John to find a solution: ‘Since people seemed to believe what I told them about how glass would perform in any given situation, I adopted, de facto, the role of determining Pilkington policy on how glass ought to be assessed in new situations.’

As Pilkington was, at the time, the only source of such advice in the UK, this became automatically UK policy – all the more so when John was asked to join British Standard Committees. ‘It is a strange thing, but when you read a standard, you don’t think about who wrote it – but somebody has to – they don’t write themselves. As it turned out, I have a natural talent for writing standards, so I quickly found myself being given that role on many of the BSI and CEN committees.’

With more and more glass being used in more ways in buildings, it was inevitable that Structural Engineers would start to get involved in glass design and specification. The more persistent among these quickly discovered that John Colvin could talk sense to them about a material which was sometimes baffling.

‘It amuses me that Structural Engineers are very nervous about glass. After all, as a material which is isotropic, homogeneous and completely linear elastic, it is the only material commonly used in construction which obeys all engineering formulae exactly.’ Some people shied away after finding out more, but some embraced the material and began to design it very effectively in ingenious ways.

Consultancy work

John left Pilkington in 1998 to take on the role of Technical Director at HansenGlass.

Still with a part time role at HansenGlass, John now operates his own consultancy to give advice to anyone who wants to know how to specify or use glass correctly, or to find out why the glass in a particular installation has gone wrong.

He enjoys talking about any aspect of building glass to anyone who cares to listen and has been a regular contributor of short courses and seminars at Glass Processing Days over the last 10 years. ‘I hate jargon and impenetrable explanations. These are for people to hide behind when they lack confidence in their expertise. There is very little in science which cannot be adequately explained to a lay person in ordinary words if you know the subject in depth.’

What John does not mention is that, in addition to being in the right place at the right time, you also need to be the right person in order to become a leading world expert on building glass applications.