flanagaj Posted October 18 Share Posted October 18 I was planning on hiring a 7 tonne excavator with a pecker to break up 200m2 of concrete slab. I was conscious that there is an LV line that runs along the north boundary and a HV line that runs across the far east side. I was hoping that I could simply crack on and spray hazard markings on the concrete where the HV line runs over. As I am using a pecker, there is no requirement to be extending the boom vertically, so the likelihood of any incident is very small. I am just conscious that if I have to request that it is isolated then once again, I am going to be paying thousands and it's money we don't have. The plan of the concrete that I need to remove is shown below, circled in red. The original plan was to hire a 1.5 tonne machine, but I don't think it will do the job. Any thoughts on this one. Link to comment Share on other sites More sharing options...
Conor Posted October 18 Share Posted October 18 Don't wing this. Think you'd be best speaking to an expert on this, and getting the DNO to approve the RAMS. It could be as simple as goal posts and restricting machine type so it cannot reach within the min safety distance to the HV line. Link to comment Share on other sites More sharing options...
flanagaj Posted October 18 Author Share Posted October 18 4 minutes ago, Conor said: Don't wing this. Think you'd be best speaking to an expert on this, and getting the DNO to approve the RAMS. It could be as simple as goal posts and restricting machine type so it cannot reach within the min safety distance to the HV line. Ok, thanks. It's ***** expense after expense. I imagine that said expert is going to be £££. Link to comment Share on other sites More sharing options...
Conor Posted October 18 Share Posted October 18 Just now, flanagaj said: Ok, thanks. It's ***** expense after expense. I imagine that said expert is going to be £££. It's part of the process. You need to budget for these things. I had a H&S expert do a site risk assessment and provide template documentation and recommendations. £250. Pennies in the big scheme of things, I spent more on spray foam. So far this year in our company, we've had one electrical fatality and at least one other near miss. The near miss would have been a fatality if it wasn't for the use of an insulated fibreglass shovel, as specified by the RAMS. 1 Link to comment Share on other sites More sharing options...
flanagaj Posted October 18 Author Share Posted October 18 3 minutes ago, Conor said: It's part of the process. You need to budget for these things. I had a H&S expert do a site risk assessment and provide template documentation and recommendations. £250. Pennies in the big scheme of things, I spent more on spray foam. So far this year in our company, we've had one electrical fatality and at least one other near miss. The near miss would have been a fatality if it wasn't for the use of an insulated fibreglass shovel, as specified by the RAMS. Am I not able to do my own H&S assessment? I was hoping that I could simply follow the guidelines as per document Avoiding danger from overhead power lines GS6 (hse.gov.uk) so long as the excavator boom / dipper cannot reach the overhead line and provide enough clearance, is that not enough? Link to comment Share on other sites More sharing options...
Conor Posted October 18 Share Posted October 18 4 minutes ago, flanagaj said: Am I not able to do my own H&S assessment? I was hoping that I could simply follow the guidelines as per document Avoiding danger from overhead power lines GS6 (hse.gov.uk) so long as the excavator boom / dipper cannot reach the overhead line and provide enough clearance, is that not enough? I can't comment on your competency There are scenarios you need to cover that might not be obvious to a non expect. E.g. how do you control for ground level changes (e.g. machine operating on a rubble pile) or visiting plant / vehicles? For context, how high are the lines? I'm assuming as HV they are well out of the way? And are you building directly under the lines? Link to comment Share on other sites More sharing options...
Alan Ambrose Posted October 18 Share Posted October 18 You could transfer the risk by getting someone in. Less than a £1K including disposal / or crushing if you can use the hardcore? The LV line is actually under the slab? You may be able to get free shrouding on the HV line: https://www.ssen.co.uk/our-services/existing-electricity-supplies/shrouding/ Link to comment Share on other sites More sharing options...
flanagaj Posted October 18 Author Share Posted October 18 15 minutes ago, Conor said: I can't comment on your competency There are scenarios you need to cover that might not be obvious to a non expect. E.g. how do you control for ground level changes (e.g. machine operating on a rubble pile) or visiting plant / vehicles? For context, how high are the lines? I'm assuming as HV they are well out of the way? And are you building directly under the lines? The ground directly under the line is a flat concrete slab, so the excavator will always be on solid level ground. Regarding line height, that is a question that I cannot answer. Link to comment Share on other sites More sharing options...
flanagaj Posted October 18 Author Share Posted October 18 7 minutes ago, Alan Ambrose said: You could transfer the risk by getting someone in. Less than a £1K including disposal / or crushing if you can use the hardcore? The LV line is actually under the slab? You may be able to get free shrouding on the HV line: https://www.ssen.co.uk/our-services/existing-electricity-supplies/shrouding/ I doubt very much that breaking up 200m2 of concrete slab including the disposal is going to cost £1k I suspect the job alone will be in excess of 5k Both the HV and LV are above ground. Link to comment Share on other sites More sharing options...
nod Posted October 18 Share Posted October 18 Try not to fit the advice to what you where already going to do Conor is spot on by assuming the worst Pennies compared to other extras that will crop up 2 Link to comment Share on other sites More sharing options...
Mr Punter Posted October 18 Share Posted October 18 Can you do the slab removal as part of the rest of your groundworks? Get the foundations done at the same time? If so, get a BFO digger with driver. Once the slab is ripped out it will be fairly muddy. Nice to get to oversite ASAP. +1 to getting an expert to do the RAMS. Link to comment Share on other sites More sharing options...
flanagaj Posted October 18 Author Share Posted October 18 Sorry, but what is RAMS Link to comment Share on other sites More sharing options...
Conor Posted October 18 Share Posted October 18 1 hour ago, flanagaj said: Sorry, but what is RAMS Risk assessment and method statement. What are you doing, and how are you doing it once you've assessed the risks? Basically. Link to comment Share on other sites More sharing options...
ToughButterCup Posted October 18 Share Posted October 18 1 hour ago, flanagaj said: Sorry, but what is RAMS Reasonable Attenuation Method Statement Link to comment Share on other sites More sharing options...
flanagaj Posted October 18 Author Share Posted October 18 Thanks all. I have contacted SSEN and they are sending someone out to advise. Link to comment Share on other sites More sharing options...
Gus Potter Posted October 18 Share Posted October 18 Asking for a friend? Why do you need to break up and remove the slab? 2 Link to comment Share on other sites More sharing options...
saveasteading Posted October 18 Share Posted October 18 A hard surface is an asset. Why turn an asset into a cost? Other people tell us to do this but it is our money. 1 Link to comment Share on other sites More sharing options...
Russell griffiths Posted October 19 Share Posted October 19 I think you need to re think this whole operation. you started off with saying you where getting a 3 tonne machine with a pecker, how has this jumped to a 7 tonner and a pecker, it could be that’s what you can get locally. if you get a bigger machine you certainly don’t need the pecker. just pick the slab up at the corner and drop it a couple of times. if you purposely want little bits of concrete then get a smaller machine 2-3 tonne and a pecker. look up the specs of the machines, as you are finding out a 7 tonner is significantly bigger than a 2-3 so far more likely to be able to get into the danger zone of working near cables. stop and re think this job, you will end up using a big hammer to crack an egg. big machines are brilliant at getting lots done, but for an amateur you can make a lot of mess and a lot of damage very quickly. 3 tonner for a weekend will see all that concrete gone. picture is an 8 tonne machine. 1 Link to comment Share on other sites More sharing options...
saveasteading Posted October 19 Share Posted October 19 13 hours ago, Gus Potter said: Why do you need to break up @flanagaj it's OK to ignore what you don't want to hear or isn't applicable and we may not know the circumstances. But we are trying to help and save you lots of money, so it would be nice to hear back. Link to comment Share on other sites More sharing options...
flanagaj Posted October 19 Author Share Posted October 19 16 hours ago, Gus Potter said: Asking for a friend? Why do you need to break up and remove the slab? Because I don't want a garden consisting of 200m2 of slab, and it's also where the house is being built Link to comment Share on other sites More sharing options...
flanagaj Posted October 19 Author Share Posted October 19 (edited) 4 hours ago, Russell griffiths said: I think you need to re think this whole operation. you started off with saying you where getting a 3 tonne machine with a pecker, how has this jumped to a 7 tonner and a pecker, it could be that’s what you can get locally. if you get a bigger machine you certainly don’t need the pecker. just pick the slab up at the corner and drop it a couple of times. if you purposely want little bits of concrete then get a smaller machine 2-3 tonne and a pecker. look up the specs of the machines, as you are finding out a 7 tonner is significantly bigger than a 2-3 so far more likely to be able to get into the danger zone of working near cables. stop and re think this job, you will end up using a big hammer to crack an egg. big machines are brilliant at getting lots done, but for an amateur you can make a lot of mess and a lot of damage very quickly. 3 tonner for a weekend will see all that concrete gone. picture is an 8 tonne machine. The hire company had either a 1.5 tonne or a 7 tonne. I just don't want to be sat in a machine for a week trying to break up a slab. I've no idea how well a 3 tonne machine will break up a slab. Edited October 19 by flanagaj Link to comment Share on other sites More sharing options...
saveasteading Posted October 19 Share Posted October 19 32 minutes ago, flanagaj said: where the house is being built OK understood. 1 Our project also has lots of redundant concrete slab out-with the house. We are retaining it because it allows a hard surface for plant and materials during the works. Seeing how the ground is churning elsewhere this week, this was a good move. In the long term we may leave it as concrete and garden above it, using raised beds, and bonding gravel to it. We will need holes for drainage. Sheds and greenhouse can also sit straight on top. This is obviously a personal choice. What we did break up was crushed on site for use as hardcore driveway. This was with jaws on the excavator: it looks like a dinosaur. 2. We are retaining the slab under the building footprint , and laying PIR on it then screed. saves removal and then replacement in whatever form. The reason @Gus Potter and I have mentioned it is because we have seen consultants and contractors remove slabs as a matter of course. On the 'not my money' principle. There are plenty of reasons why slabs need to be removed. I don't know your circumstances . 1 Link to comment Share on other sites More sharing options...
Alan Ambrose Posted October 19 Share Posted October 19 Is this the base of a former cattery or am I mixing things up? If something like that then suggest it’s not very deep with minimal reinforcing. You could dig down the side of a bit and look. Then belt a corner hard with a sledge hammer and lever with a big pry bar. If that’s easy then smaller, if you made no impression, then larger. Do you need to remove/move any hardcore that’s underneath? Link to comment Share on other sites More sharing options...
BadgerBodger Posted October 19 Share Posted October 19 FYI useful docs for guidance are GS6 (overhead cables) & HSG47 (underground services). First port of call for general guidance on the topics and industry standard protocols. There are also explanatory notes documents for both if I recall. https://www.hse.gov.uk/pubns/gs6.pdf https://www.hse.gov.uk/pubns/priced/hsg47.pdf Link to comment Share on other sites More sharing options...
Russell griffiths Posted October 19 Share Posted October 19 for a bit of context I was at kubota this morning. the big machine in the pic is an 8 tonner, next to it is a 3. considerable bigger reach and height. 1 Link to comment Share on other sites More sharing options...
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