Don't know about nails into cast iron columns but I do know that when involved in fire, water will just make them collapse due to their brittle quality as you say.

Good luck, I will watch this one with interest.

Listen to Bob as I sure that such practices are not suitable and sufficient

Stress is built up in the cast iron which can manifest itself as a brittle failure / deformation at a later period especially so as impurity in the 1900's was a big problem and impurities are a prime factor in failure of cast materials. Luckily such columns were over engineered otherwise more would have collapsed but by undertaking such actions the structural strength is probably compromised

The client should have somebody in place to appraise and confirm the system of work e.g. A structures expert who specialises in mechanical - fabrication engineering [as against a civils only expert] / metallurgist or similar and I have yet to meet a day to day builder who knows about the structural integrity of metals especially exotics and casts or, in most cases, cares about the subject

Once the builder is off site and paid the problem lies with the client and this appears to be yet another case of the client being given poor advice

Is this a notifiable job? If so was the CDMC suitable for the work in hand

An alternative is to contact a foundry that still casts iron, there must be some left. They may be well placed to answer your question.

Over the years numerous redundant old textile mills incorporating cast iron columns and located in various parts of the UK have been converted with interior partitions to create domestic flats and industrial units. Thus, it should be reasonably feasible to find structural engineers and others with appropriate experience and knowledge of affixing partitions of various types to cast iron columns.

My late dad was involved with cotton mills and their machinery in his teens and twenties, and once told me that cast iron columns were extremely strong in compression (probably over-engineered in many cases with greater-than-necessary wall thickness), but pretty weak if exposed to tension or shock. Therefore, any lateral forces applied to such columns should be kept to a minimum and balanced, whether applied via fixings inserted into them or via non-invasive 'bolt around' fixings. It might be worth having a look at the nature of fixings, if any, on/into such columns if you can. Also, if you know of any industrial premises which have such columns and remain in use, their engineers might be willing to tell you about the types of fixings used and also give you a rough idea about what loadings can be imposed without incurring problems.

If invasive type fixings can be used, my inexpert guess is that drilling holes for such fixings is likely to be a far better method than any which involve single impact like a nail gun or repeated percussion as with a hammer.

Stop work and as Paul says.. get shot of him (no punn)

Thank you very much everyone, your input and knowledge has been very useful and is greatly appreciated. The client has kept the builder on site and will not consult a structural engineer citing cost. They have now ceased shot fixing, not from advice, but because some of the fixings will not enter the columns. They are now drilling and tapping.

I'll be speaking to them about the CDM Regs but fear that this will be swept aside. Naturally, I'll be keeping copies of my correspondence with the client, so on their head be it - I just hope not literally. It really makes me want to walk away, but then the workforce will be left with no-one to promote and improve safety matters.

Many thanks again. Paul.

Drilling and tapping is still creating fracture nucleation points!
You may be torn between the devil and the deep blue sea here as the old saying goes!

Paul, you are taking a much too narrow view of failure. In engineering, failure has a broader definition, because, for example, if a safety critical piece of material buckles, the structure fails. To analyse structural integrity you have to take this leap.

I do not dispute that yielding and buckling are simply deformation (and the latter may be purely elastic), and do not result in the material falling into pieces. However, here we are dealing with a structure, so such events can, and do, lead to collapse of a structure. Incidentally, buckling of a column in compression gives rise to tensile and compressive stresses on the surface of the column as it deforms, so is extremely important in this instance.

As for glass failing in compression - ceramics, if compressed sufficiently, will fail, by the propagation of cracks at an angle to the applied stress. This is why I suggested the simple experiment. It is evident that you can cause ceramics and other brittle materials to fail when you apply a compressive load to them. Ceramics and other brittle materials are often orders of magnitude stronger in compression than in tension, but they can and do fail. Since many of them have very little capacity to yield, the failure tends to be catastrophic (dustpan and brush job).

This reply makes me think about why do we keep notes in case something happens?

We are all now aware that cast iron should not be tampered with as in the thread so why not take the issue that bit further to prevent the potential accident from occurring?

I often hear lots of people say "make sure you keep the records to prove you told them ..........???????

My point is find out who or what is the next step up and take your concerns there.