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Alfasev  
#1 Posted : 17 May 2019 11:43:27(UTC)
Rank: Super forum user
Alfasev

The HSE have just issued a press release on stability during demolition.  Some of the wording is troublesome as the HSE are indicating the design team decided the demolition method, for example:-

Case Study 12 Unchecked change to system of work caused collapse: A cinema was being demolished and the workers decided to speed up the job by toppling long span roof trusses to the ground instead of lifting them down as per the method statement. This caused a section of concrete roof slab to move and topple the upper masonry storey which in turn pushed the perimeter scaffold away from the building, so it overturned and fell across a high street. Vehicles and members of the public were trapped beneath it. It stopped just short of a supermarket plate glass window completely blocking the road. By sheer luck no fatalities or major injuries resulted. The planned and designed sequence of work must always be followed unless changes are fully assessed and agreed by the design team.

Having done a few demolitions (nothing unusual) the demolition method has always been decided by the demolition contractor and recorded in the demolition plan, applying BS6187:2011 Code of practice for full and partial demolition. I appreciate on some projects there has to be close liaison and detailed planning between designers and the demolition contractor but not on a standard demolition only projects.

The issue for me is with the HSE’s interpretation of CDM 2015 regulations to demolition. They are shifting the responsibility and duty for the demolition method to designers and the principal designer, away from those who hold the expertise, with huge consequences.

The term “design” does appear in BS6187 but is not defined but they are saying because it is mentioned it is now the responsibility of the design team! However BS6187:2011 paragraph 5.2.2.2 states “the contractor should be given the freedom to determine the proposed method of demolition”.

I would be grateful for people’s comments and thoughts

achrn  
#2 Posted : 17 May 2019 12:44:00(UTC)
Rank: Super forum user
achrn

Originally Posted by: Alfasev Go to Quoted Post

The issue for me is with the HSE’s interpretation of CDM 2015 regulations to demolition. They are shifting the responsibility and duty for the demolition method to designers and the principal designer, away from those who hold the expertise, with huge consequences.

   

No, they are placing the responsibility for the designed sequence of work on the designers of that sequence of work, which is generally (but not always) the demolition contractor.  If the demo contractor has designed the demolition, they are the designer, and their own operatives must not alter that sequence without consulting their own design team.

'Designer' is the person or organisation that designs.  'Design team' is the subset of that organisation that designed this scheme.  It's completely irrelevant if they are generally regarded as being a contractor organisation.

We are not contractors, and we do undertake design of demo schemes, some of which are rather unusual.  However, we are also involved in more normal demolition prior to e.g. works we have designed being built and where the contract is set out that the demo contractor designs the demo scheme they are the designer of that element of the works, and I see nothing in the HSE release that suggests we would be taking any responsibility for what another designer designs (assuming we are 'just' a D and not the PD).

I observe that demo contractors (in my experioence) are particularly prone to a cavalier attitude to method statements and designed sequences of work.  We normally require one of our own people on site full time where we have desigedn a sequence.

Edited by user 17 May 2019 12:58:40(UTC)  | Reason: spelling

Alfasev  
#3 Posted : 17 May 2019 13:37:16(UTC)
Rank: Super forum user
Alfasev

Design in CDM 2015 is defined as “includes drawings, design details, specifications and bills of quantities (including specification of articles or substances) relating to a structure, and calculations prepared for the purpose of a design;” and not the sequence of work.

Is not the sequence of work planning, managing and monitoring of the construction phase?

achrn  
#4 Posted : 18 May 2019 06:02:41(UTC)
Rank: Super forum user
achrn

Originally Posted by: Alfasev Go to Quoted Post

Design in CDM 2015 is defined as “includes drawings, design details, specifications and bills of quantities (including specification of articles or substances) relating to a structure, and calculations prepared for the purpose of a design;” and not the sequence of work.

Is not the sequence of work planning, managing and monitoring of the construction phase?

Not if it requires a particular sequence to maintain structural stability.  I would regard planning of the construction phase as for example deciding how many people or what equipment you need to have on site to complete each operation.  Deciding which operation is needed is designing the demolition.

Possibly it's to do with the complexity of the schemes you're talking about.  I will accept that a demolition that does not require any drawings may not require a designer and can simply be treated as a 'planning the work' exercise.  However, (by definition) I don't do any such work - the demolition we get involved with has drawings and calculations.  The demo contractors we work with employ designers - sometimes us, sometimes others (and very occasionally, in-house)

If the works have drawings or calculations then that's a design, and where here's a design, there’s a designer.

peter gotch  
#5 Posted : 18 May 2019 11:44:23(UTC)
Rank: Super forum user
peter gotch

For all but the simplest structure you would expect demolition to follow a process that included consideration of what unexpected surprises should NOT be unexpected. For example review of whatever drawings and other records exist, supported by surveys and perhaps some investigation(s) [often including an intrusive Demolition Asbestos Survey]. All this provides information which then informs the choice of demolition including any constraints such as the need for temporary works or specific sequencing. All this constitutes "design".

Alfasev  
#6 Posted : 21 May 2019 10:44:22(UTC)
Rank: Super forum user
Alfasev

I appreciate both of your posts, so bear with me.

I am still struggling with designing sequence of work for demolition. For me it is not design as defined in the CDM regulations and is the demolition plan or method statement. Remember I am not talking about complex structures, just standard one to three storey buildings.

 “Design, designed, designing” are terms used loosely in places in BS 6187 which is a guidance only. The CDM 2015 regulations is statute law and defines “design”. BS 6187 pre-dates the CDM 2015 regulations so there is a mismatch in terminology and it is far from clear.

If HSE want it considered as “design” they need to issue a dictate but in the area of the market we operate in that poses difficulties.

So the Principal Designer has to plan, manage and monitor, and coordinate the “designing of the demolition” or sequence of work. Therefore if something goes wrong and it is deemed that sequence of work was not detailed enough and inadequate is the Principal Designer at fault?

When does the primary responsibility shift to the Principal Contractor?

If “designing sequence of work for demolition” is design under the CDM 2015 regulations then the only organisation that can be the Principal Designer is the demolition contractor as they are the only ones that have the required amount of control over the design.

achrn  
#7 Posted : 22 May 2019 13:06:58(UTC)
Rank: Super forum user
achrn

Originally Posted by: Alfasev Go to Quoted Post

So the Principal Designer has to plan, manage and monitor, and coordinate the “designing of the demolition” or sequence of work. Therefore if something goes wrong and it is deemed that sequence of work was not detailed enough and inadequate is the Principal Designer at fault?

When does the primary responsibility shift to the Principal Contractor?

If “designing sequence of work for demolition” is design under the CDM 2015 regulations then the only organisation that can be the Principal Designer is the demolition contractor as they are the only ones that have the required amount of control over the design.

I don't understand why you (apparently) think this is any different to designing something going up as opposed to something coming down.  When does responsibility for those operations shift to the Principal Contractor?   (In my opinion - never - the designer remains responsible for the design, both in construction and in demolition.  The PC has responsibility for planning and managing the work that executes the design, whether that is construction or demoltion or both.)

It's quite likely that the demo designer will be PD, yes - because it's quite likely that they are the only designer at that time.  So what?  It's just the same as design for construction - if there's only one designer involved, they will be the PD.

Unless you're arguing against the whole of CDM and all PDs, I don't understand what the objection is.

Alfasev  
#8 Posted : 23 May 2019 14:10:26(UTC)
Rank: Super forum user
Alfasev

There are issues with CDM 2015 and particularly the Principal Designer role. We are encountering more and more designers and Principal Contractors refusing to be the Principal Designer, us included. This leave the Client acting as Principal Designer!

As stated the demolition contractor should be the Principal Designer and some demolition contractors have a cavalier attitude. In deciding that the demolition method statement is design “design a demolition” and that other designers are excluded from acting a Principal Designer as they will not have the required expertise and degree of control of the design, the HSE via CDM 2015 have successfully removed any oversight on a demolition only contract.

“Design a demolition” is not accepted practice or term used in the area of the market we operate in, a demolition method statement is prepared. May be it should but I cannot change a whole industry!

The issue is what is and is not design. It seems to be expanding to cover a lot more than that historically believed to be design. Applying the Oxford dictionary definition for example “Purpose or planning that exists behind an action, fact, or object” and not that defined in the CDM regulations.

Why is this important? Most designers strive to comply and the HSE appear to be shifting the duty for planning that exists behind an action for example method statements on to the designers (architects & engineers) and principal designer.

I accept there are complex and difficult projects in which designers play an integral role in deciding what occurs on site, but not on a standard two or three storey build.

In demolition the Didcot Power station collapse may provide answers when CDM 2015 will debated and tested in court. I believe the Principal Designer for that was not the demolition contractor, but I may be wrong.

peter gotch  
#9 Posted : 23 May 2019 14:33:56(UTC)
Rank: Super forum user
peter gotch

Alfasev

Don't hold your breath for Didcot Power Station or any other demolition project to cast much more light on the interpretation of design within CDM.

A simple check on the HSE prosecutions database (and the history database) shows that there have been very few relevant cases brought to conviction under CDM.

HSE seem to be tending to reverting to Section 3 (in particular) of CDM.

and the evidence that they are actually targeting CDM designers and PDs is sparse. Lots of annual statements of intent, little execution.

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