Scalpel Tower: Solving Complex BIM Challenges | The BIMTech Podcast #9

In this episode of The BIMTech Podcast,  Matt McGuire, sits down with Mark Cain, BIMTech’s Manchester BIM Manager, to break down the Scalpel Tower case study. A deep dive into one of their most complex MEP coordination projects. From the building’s tight footprint, storage constraints, and congested corridors to HV cabling, slab loadings, plant space, prefabrication, builderswork, and anchor/expansion challenges, Matt and Mark share insights from the front lines of delivering precision on this iconic structure. A must-listen for engineers, designers, and anyone curious about what it really takes to bring major buildings together behind the scenes. 

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No what? Mumbling? No swearing. Well, I can't guarantee that. All right. Welcome back to another edition of the BIMTech Podcast. Been a bit of a long time in coming this one, because today I'm joined by. For anyone who works closely with BIMTech or clients or whatever probably doesn't need much of a introduction, but it's the legend that is, Mark Cain. Otherwise known within BIMTech as Yoda, as he's a bit of a fountain of knowledge. Well, you know. Self proclaimed. And he’s also our Manchester BIM manager. So. I’ve got Mark here today. I've done a bit of an introduction for you, but I don't know if you want to say anything about yourself? Big yourself up. No, no, no, to be honest with you I wanted to mentioned about the fact why we knew each other, you know, in as much as that, you know, we’re probably boring people to death with all this. You’re throwing me under the bus now are you? I am going to through you under the bus, yeah mate. So basically, me and Matt were apprentices at a ductwork company in Harpurhey, Manchester when we were 17 - 18 and, yeah, we were dragged up, doing ductwork weren’t we mate? We certainly were. Yeah. And anyway, that company went bump and we kind of separated ways and about how many years ago now, probably 12 years. 13 Years. Something like that. We joined forces again and, yeah. Never looked back really, have we I suppose. Here we are today. Who thought back then we'd be sat doing podcasts. To be honest with you mate, I didn't think I'd ever stop using a drawing board, so i'm not really one to talk. So there we go. So today. Anyway, we're going to just basically talk about quite a large project we worked on. Well, we completed it in 2019, so I think it's safe enough now to talk about it. And we're just going to talk about some of the sort of pitfalls on the project and reasons why sort of BIM was the tool that helped us to deliver it so successfully. Yeah. So the project is Scalpel Tower in London. Otherwise known as 52 Lime Street, and it's in the Bank District of London. And it's quite an iconic building and it's opposite the Gherkin and, I think, I don't know why it was called... Is it meant to look like a scalpel blade or something? Is that why it was scalpel tower? To be honest with you mate, I can't honestly remember why... I think that’s what it was... I think. Because it has got, like, this weird, kind of iconic. Roof hasn’t it to a point... Sort of like a blade at the top. Isn’t it? So I think that was the idea of the scalpel. Yeah. I think there was about 40 floors of office space. 44, and then 47 up to 50 something. Yeah. There was a few floors of plant at the top. They were quite awkward because the footprint, went a lot smaller. But it was very narrow and there's a lot of steel work in there and everything. So that was quite a complicated area. Yeah. Then you had the ground floor, which was more like a reception. And I think there was a loading bay within it and things like that. And then we had three levels of basement. Yeah. B3 the lowest basement was like concrete water tanks weren’t it. Yes. Sprinklers tanks main level up and then another one up from that. B2 was the sort of the main plant areas where you had a lot of the sort of switchgear and everything. Yeah. And then B1 was more like back of house areas. Back of house yeah. With showers and... And a cycle store. Changing areas, all that sort of stuff and a little bit of plant as well in there. But that sort of summarises the building. I think the idea was, there was a main client and his intention was to take a few of the upper floors himself. Yeah. And then was leasing the rest of the building out. So again, it was one of these projects where like a lot of projects these days where the project had to be finished on time because there was going to be a lot of costs if the project over ran. Yeah. Well, it didn't help that the guy who actually paid and owned the building was like right at the top, do you remember? He had the two top floors. He wanted the penthouse didn’t he? For himself I think we built an atrium for him didn't we? there was an atrium that kind of... I remember, it was all soundproofed walls around it. And there was plant above his office as well. It was all on springs and everything. Spring loaded. Yeah, I remember all that. Yeah. Yeah. So anyway, what we were going to do was just talk a little bit about some of the sort of like, I don't know, like the problems we had to overcome. I think some of them are fundamental problems that you get in London all the time. Like, I think what you tend to get or what I find is generally in London, especially in the bank area, the buildings are very tall, but the footprints aren't necessarily as big as you would expect. Yeah. And the reason being is obviously, land and that is a premium in London. Yeah. So things tend to be a bit smaller. The other thing is they try and utilize whatever space they have got to try and utilize it. So there's not a lot of outdoor space around. So... I think if memory serves, I think it was something existing, like probably most new construction, near the center of London. There's always a building comes down first before something goes up. And a lot of the buildings, the shape of them and the footprint is all dictated by surrounding buildings and roadways, you know, it's... Yeah, because of that one of the issues is, is that externally of the building, there's not much storage area. So what we found is as we were doing coordination and everything, and when we were visiting site, we did visit site quite regularly that a lot of the space, where things should be getting installed were being used as storage areas. You walked down the corridors and the corridors were a bit, I don't know, just a bit fuller than I thought on the floor level for storage. And trying to get scaffold towers around them and different things... Didn’t they have some of the office space there as well? If I remember right towards the end... Oh the site offices? The site offices and stuff I think some of the area turned into... because, like you say, I think especially for the site teams and that where they want to store all the materials and everything, I think that all did end up moving into the sort of basements. Which again, is just something else to avoid or something else to work around. Yeah, I think it all becomes a programing issue, doesn't it? Yeah. There was areas that we knew later on in the project would be congested with materials or whatever. Yeah, yeah. So it made it probably more awkward for the guys on site. But for us it was stuff worth knowing. Yeah. Because it did change a little bit of how you would coordinate services certain services that you'd want to keep out of these areas. Because like the HV cables because it's a continuous cable. And, you’re not stopping and starting with the install of it, it's got to be done in one hit. So, if you know there's an area that you can't get into, you've got to avoid that. Yeah. So it was things like I guess and like I say in the corridors, I remember walking around site and I felt sorry for some of the guys when you saw how cluttered some of the corridors were. Yeah. But again, that was more of a site issue. But then going on to, I just mentioned about the HV cables, I don't know. Well, I'm sure you have got thoughts about it because I remember one of the problems was actually pretty comical really. It was the usual thing, it was diverse routine. Yep. And there was also fire protection, wasn't there? Which was that? They went for Kemwell was it? Yeah. It was. I think it started off they were going to go for that Durasteel. Yeah. But I remember it was at the slab. Yeah. Then it wasn't and it was up and down and if i recall, was it because of the weight of the drum at one point and the continuous cable wasn’t it? Yeah, I remember sitting in meetings with this so, HV cable, you tend to try and get in as the high service. You tend to fix it to the slab, and then you put a three sided box around it. Yeah. To protect it. And protect it from fire or anything else. But in this instance, we couldn't put it as the high service, because what you tend to do is you put it in and then you forget about it. But like I said earlier, you have to run the HV cable from start to finish. And because the start of it was in the basement and the finish of it was going to be up at sort of level 40 or 44 or whatever it was, it had to be a continuous cable, well it was tri cables wasn't it? Yeah that’s right. So it had to be these three cables going diverse routes had to get up to that level and it had to go in one hit. So as soon as they started putting the cable in, it had to go all the way, otherwise they had to have it on a drum somewhere stored. And because the cable was that heavy. Yeah, they couldn’t store it could they? When they did the calcs they had nowhere to store it because the slabs at like ground floor and first or whatever could not physically take the weight off the coils. Yeah I remember that. So because there was no where to store the cable, they said the HV cable, as unusual as it might be, has to go in the last. So we had to come up with a way of getting it in as the lowest service, which is quite unusual. Well it was... Again, it was something that we were, you know, part of way through the coordination certainly in the basement areas that I was doing and all of a sudden then it was like, well, actually, you know, this thing can't be tucked up against the soffit and out of the way. It's got to then come down and then it's access after that. I think, was it the three sided Kemwell that we went for? I think it had to be four sided didn’t it? No, but I’m saying they only installed the top and the sides, left the bottom out, cable went up and then obviously they finished the bottom. But yeah, it was. Well the other thing I remember as well was because normally, like, again, if it's up against the soffit, if there's a fire or anything below and the services all collapse, it's at the slab and it's safe. But when its as the lowest service, it wasn't just making the Kemwell secure that. The Kemwell was the protected box. It wasn't just making that so that wouldn't fall down on the fire conditions. It was making sure it could take the weight if everything collapsed and landed on top of it. Yeah. So we ended up I remember there was like a bit of a subframe that went above the top of it. So if anything fell, it landed on top of the subframe rather than on top of the HV cables. So that was, a big issue on the project. But I think probably enough about that now because people will be bored and I nearly swore then. So I'll leave that for you. So the other thing, I mean, I know something that was a bane of your life on that project was the slab loadings. Yeah. So, basically what it was, I was nearing the not the end, but I was nearing to a point where, you know, the majority of services were in. We settled on you know... This was on the basement B2? This was on the B2 basement. and the main water plant room which had all the major chilled water heating pumps, all the domestic plant, you know. And that pipework was big. I mean, the chilled water was like 250 diameter wasn’t it? Yeah. 300 dia some of the headers. The plate heat exchangers were something like 2.5m tall. I forget the weight of them, but they were colossal things. And basically, you know, we were being told we did, pump skids and the plate heat exchanger skids. But pretty much everything else was traditionally installed from the soffit above. And out of the blue towards the end of modelling, somebody had raised the question about, has anybody checked, that the... I remember being sat in a meeting when that got raised. I bet you were sat there saying I've got to go back and tell Caino this one... he's going to lose his head. But, yeah. So basically what they realized is that the structural engineer had, basically calculated the floor load of the floor above just to take what was there. And basically it was just toilets for, I think, the cycle store. Yeah I think it was the shower rooms wasn’t it? Shower room or something like that. So they realized quite late on that in actual fact, that slab above the plant room couldn't take the building services that we thought were being suspended off it. And right at the end, we got told then that the whole of the plant room services had to be basically, supported off pedestals and framework and steel and goal posts and everything. Yeah, it was, to be honest with you I remember at the time it was like you thought that it was just going to be, you know, an absolute trauma. But to be fair, because, I think I’d decided early on that I was going to leave a decent zone for drainage because I think we had sprinklers, the sprinkler mains are high level and a lot of drainage and what have you. We had a lot of crossovers and, at the time, more luck than judgment. Don’t say that. I know, yeah. I left quite a decent zone at the top, so don't ask me how, but we managed to shoehorn in without too much alteration to the MEP services is like I say, all that steelwork and goalposts. But it was... Almost created like a steel framework. You almost created like a steel framework box didn’t you? Yeah, yeah. That fitted in the plantroom first and then all the services fitted within that. Yeah. But, yeah, there was a lot of gear in them plantrooms. Hell of a lot. Yeah. And then talking about the plant rooms, another thing that we did do quite a bit of, was the DfMA. Yeah. So the prefabrication. Yeah. So... But it was mainly just plant wasn’t it? We didn’t do much on distribution apart from risers. Yeah. Yeah risers were DfMA. But, yeah in the plant rooms, it was mainly pump skids and the plate heat exchanger skids. But again, when we're saying there about the plate heat exchangers being like 2.5m and they weighed an absolute tonne. Again, it was the logistics of how them things move through from where they get lowered into the basement. You know, I think we had, I forget the technical term for it. But the wall down plan. So there were certain walls that couldn't get built. And it's like I say, it's logistics of where they get dropped down. And then we had restrictions then on sizes of frames. I think if I remember rightly as well, there was like a location in the ground floor where there was going to be an opening left in the slab to drop down into B1. But it wasn't directly above the hole down to B2. Yeah. So you'd have to drop it down to B1, then move things around B1 to get to the hole that drop down to B2. And then move back around again to get into the plantroom. Yeah. So there was quite a bit of planning to be done on that. With head heights and everything else. And that was the other thing wasn’t it? Because your skids virtually going last, as it were, because you know, you want to be installing all your high level services. You don't want plant skids below to work over. Exactly, yeah. So you know again that all has to come into play about, you know, you've got to think about how these things get skidded in after all the high level services have gone in. and have you, you know, got the logistic path for doing that. You also have to look at which I know it's going to sound obvious when I say this, but when you're in the mindset of modelling something in 3D and you're putting it in its final position when you've got it on that skid frame, it’s sat on the floor, when you're maneuvering it to get it into position it’s going to be on some sort of a wheels. Yeah. So it's going to put an extra maybe 6in or 8in on the height of it. Correct, so that's again when you're doing all this skid work, that's what you do have to consider, is that, you know, the skids will raise up so far. And then you can have jacking points. Sometimes you can have AVMs as well. So again, you have to think about all these things about, you know, what space you need to actually move this thing isn't necessarily it's finished level. You know, when it is dropped into position. But yeah, no it is, you’ve just got to think about everything involved haven’t you. It’s like... just jumping onto the risers here because that was again we did quite a bit of DfMA on that. And I remember one of the things early doors was it was anchored at the basement and then everything went upward. So any expansion the riser grew as it went up. Yeah. So when you go up a couple of floors you're only talking millimeters. But when you’re going up 10, 15 floors, it's starts coming into, it can be like 50-100 mm or whatever, the sort of, distance when it starts to expand. And I remember us having to actually work out well on one of the upper floors when the building's operational and everything expands, the branches are going to move by, say, 100 mm. So I think we actually physically moved the riser module up 100 mm and reran the clash detections. Because we said when it's in operation, that's where the branch is going to be. It's not going to be where it is now in a... Sort of... I think we had to... Did we have to do some sort of calc. or somebody did some sort of calc with a cold draw as well in the chilled. Yeah. So your heating is expansion but your chilled is contraction isn’t it? So I know... They said they don't normally worry about chilled water. But they said because it was... Because it was so big and such a high building... I think it was because of the diameter of the pipe as well. Yeah. Because it was such large pipework. But while we're on the subject of them risers, obviously, you know, we're about the anchor point in the basement. Yeah, it a bit of a faux pas there wasn’t there? Yeah so, if I remember right we came down. It wasn't so much the anchor, it was the dirt pocket at the bottom. It was the dirt pocket that was the problem. So there was a branch, there was a dirt pocket with the IV and everything else. I think possibly, you know, 50mm stab off with an IV and a drain. So basically what they said was, well, what we'll do, we'll flange all that. We'll have a false piece of pipe, a stool pipe down to the actual basement floor level. And we'll use that as an anchor point then for the expansion of the riser. And then, again, something that we didn't consider, was the actual valves involved wasn’t it? Yeah. And they realized that the forces involved on this valve at the dirt pocket would basically crush the valve. So then there was another secondary cantilever affair wasn’t there? Back to the shaft wall, to actually take some strain off. So yeah, that was again, that was another steep learning on that one. Yeah. The other thing I remember as well, again, like what we were saying about with the footprint being fairly small, there was so much plant down in those basements, but because the footprint wasn't massive, I remember like, the distribution corridors, like, it's a basement, so there isn't a ceiling in there. But if you imagine a ceiling at maybe 2.4m. Above that level up to the slab, you had about 2-2.5m to get everything in. But what it meant was your corridors were fairly narrow, but very tall, the space. So the logistics of getting all the services in and them being maintainable afterwards was a bit of a nightmare, wasn't it? Yeah. Because again, you've got to think about, you know, first of all what services do you want at the top that's going to have limited access. But the fortunate thing is that nine times out of ten one of your top services is your drainage. And then you've got to consider about the rodding eye points for that. And I remember we were extending kind of. On the Y’s with the rodding eyes, we were extending that rodding eye to a clean spot weren’t we? Yeah. Where you can actually get up to and actually rod through. So it wouldn't necessarily be on top of the last Y connection. It’d actually be where you can actually get up to. Yeah. You know so yeah. And it was a case of layering from the top. And like you say, going back to the HV with the Kemwell, that chucked quite a big spanner in the works towards the end. Where all of a sudden that had to come down. And you had to consider that for the access. And other thing I remember with the corridors was that we ended up using Trimble Field points. Yes. Because we realized there was that many different sprinkler systems at the top. Yeah. That there was almost a blanket of sprinklers down the corridor. And they were like main distribution pipes so they were quite big. And we said once them pipes go up, no one's getting back to that slab again to drill it. Yeah. So as the trays come lower and lower in that corridor... How do you get back up? The access to the slab just gets more restricted. So the idea then was using Trimble field points you can pre-drill all the slab and get all the anchors already installed and a bit of rod or whatever. Yeah, they were putting all the rot down weren’t they? The rod was there then for all the other trades to connect onto. Yeah. So that was I mean, it was a good solution for what could have been an absolute nightmare. Yeah. What I did think was good on this particular project, especially for us, was that they actually had somebody doing, like, a stage five architectural model. So they were putting all the, like you say, lintels in. They were all getting modelled in. Even every single hole we requested got modelled in. So there was a hole there. Yeah. So when we could run a clash detection. Yeah. It was... If there was a pipe going through a wall, it wouldn't come up as a clash, because there's a hole there and it goes through the hole. A lot of the times when we work now, we never got that detail of architectural model. So you run a clash detection and it'll come up and say, your pipes clashing with the wall and blah, blah, blah. You have to basically just discount them because, you know, the holes not there to be formed. And, all we can do going forward is, believe it or not is, you know, clash detection against our own builderswork sleeves, you know, and that's... But it was a great way of seeing if a builderswork opening had been missed. Yeah, yeah. Because if it had been missed, it’d come up as a clash because there’s no hole there. So it was a very quick way of running a quick clash detection and seeing whether any holes had been missed. But like I say, I think it's few and far between. Apart from the main structural concrete like your sheer walls and that. People tend to model in the openings in them. But when it comes down to blockwork and studding, it's very rare that we get any architectural models. And the thing is, you know, you touched on there, with drywall, plasterboard walls. In as much as that, you know, we have to account for King stud arrangements that aren't there for us to physically miss. Yeah. Sometimes. And, you know, having that work interface with architects, with your fire stopping people with your fire damper people with, you know, British Gypsum, and everything else. You know, there's a lot of individual elements there that need bringing together and, you know, not to blow our trumpet, but we're kind of like the interface to bring those people in and, you know, there's a lot of contracts now where, from a builderswork point of view you know, a lot of the rules have to be set out really early. And, you know, I'll completely admit that years ago, I'm sure you'd agree that the builderswork almost went in at the end to a point because we’ve seen that as, well what's the point in putting in builderswork, when all the MEPs got to go to construction all your holes are going to change anyway and everything else. Whereas nowadays, you know, one of the first things that we actually establish and even model in the builderswork details. It's kind of almost dictating the coordination now. Oh it is, yeah. The thing being is, though, there’s still differences out there, which, you know, isn't worrying, but it's just a fact of life that, you know, people can interpret different rules and regs. But, you know, ultimately, you know, it's one of those things now on any project that, you know, I kind of, you know, push the client into setting out those rules so that, you know, again, it's getting people on board that wouldn't normally be on board at early stages in the job. But it's very important that they are. And as I just said before, it's your fire damper people. It's your fire stopping people. It's your walling contractor with British Gypsum and it's bringing all them people to say, right. What rules are working to? Because you have deflection zones as well don’t we, in dry walls where, you know, there's the building tolerance, there's settling of buildings, you know, there’s expansion during fire where you know, something needs to be allowed for, you know, for that as well. And, you know, there's a lot of moving parts that I don't completely understand, but, you know, I know what effect it has on building services. Yeah, well, I know, like, if a slab deflects by 25mm for example, I think you have to allow of the build up of a plasterboard wall you have to allow about 200-250mm for it to be able to compensate for that 25mm within it. Without it then deflecting onto the actual builderswork opening. Yeah. I mean we've had all sorts haven’t we, over the past few years and say fire damper holes. Obviously they have to be in their own separate holes. But separation of holes, shall we say, between services or the fire dampers, we've had everything from 100mm to 200mm to 300mm. You know, there's a lot of difference out there. And, you know, it's pinning someone down to say, right, you know, what are those rules? And to be honest with you, they need to be cast in concrete because, you know, there's quite a lot of jobs where even when you've gone to that diligence of actually, you know, producing those rules, you get, you know, somebody comes on board a new walling contractor or a new reg change or something like that. And those kind of things, the amount of times even nowadays that, you know, the amount of change that we have to go through because of... This one you will like though. Is that sometimes there's that many different rules. You can’t achieve everything. No exactly. And somebody will come up with your favorite saying, engineers judgment. It's just it frightens me. It frightens me. When those words get used, all of a sudden it's you know, with all due respect, you're not gonna... Well it’s like, who's the engineer? And why is their judgment... Yeah....Acceptable? And then you find out further down the road that it's not acceptable. Exactly. Oh we've had plenty of jobs where the easy get out is the engineering judgment. And I've said, you know that. Well, fortunately, I'm telling you now, it will not happen because you're asking for somebody to basically put their name on a piece of paper to say, yeah, that wall in that circumstance will stop a fire. And I'm sorry, in this day and age now, that's just not acceptable. Unless it's been tested. Yeah, exactly. I remember with one of our clients, I won't name them. It was a good thing actually, but I'm still not going to name. They give me the opportunity to sit down in front of their sort of buying department and explain to them why we need what we need when we need it. Yeah. And we would say just about, say, a pump for example. And I was trying to explain to them why we needed that information to be accurate. And I said to him, I said, just imagine we're installing it, just think of it that way. I said, we are in a virtual world installing it. I said, so if you had somebody on site going to install that pump, I said, could you tell him it's one of three? Yeah. One of three manufacturers we're going to go with. I said he won't be able to install it. He needs to know the exact pump that he’s installing, I said, and we need to know the exact pump that we’re modelling and putting in. I said, because otherwise it's not going to work. And when it comes to site it's not going to fit. Especially around, you know, DfMA areas of work, I mean, well, you know. When you’re working to the mm. It’s either accurate or it’s wrong. There's no tolerances. No in-between. It’s either right or it's not going to work when it's put together, you know, and yeah. There’s a lot of moving parts like you say, there's a lot of things that I’d wish, would be sorted out early. You know, CDP elements of work, you know, sprinkler designs and things like that. You know, what we tend to do as you know, is, that if we’re coordinating services and all be it, you know, coordination design of the sprinklers isn’t necessarily in our scope. We still have to allow for that. So invariably we will always allow mains and suchlike and systems of how branches come off. But again, it’s one of those elements of work that seems to be brought on board very late in contracts that then, you know, we have to either work around or, you know, because all due respect, we're not sprinkler experts. You know, that's the reason why these guys are brought on board, because, you know, they’ve got the expertise and such. And again, just all late engagement that you know. If I was to wind this up now and I said to you just to finish off what is as somebody who coordinates building services, creates 3D virtual models, what is your three biggest bugbears that you have to contend with? Three biggest bugbears is builderswork rules getting set in concrete early days, procurement equipment and even simple things like, you know, the valving with the databases and the insulation, the materials and everything else is that everything is set early days in basically as robust position as it can be. And then further on down the road, like you say, there’s less changes, you know, there's less waste basically, time and money. You know, all because, I mean, I understand, you know, if you need a pump set, you know, a year down the road than we start work, that's the mindset it’s I don't need to sort that because I don't need it yet. And it's like, yeah, but we need it because you're asking us to coordinate it, you know? So yeah. So yeah, that's the big things at the minute. Right. Well, thank you very much for that. No it’s alright, it’s been a long time coming hasn’t it? Yeah. I hope you’ve given a few people watching a bit of an insight into the sort of trials and tribulations that face you every day. I don't think there's too many bleeps is there mate? I don't think there was any actually.*if you want you can do one and I’ll bleep it* F***ing Hell!