Service clash and visualising drawings.
The East Office at Hinkley Point is a 13,000sqm building formed of 12m x 3.6m x 3m modules. Currently undergoing first fix services it is the furthest along of three similar structures on site – it is not yet water tight but that is a different issue.
This post is just to quickly share the issues that have been experienced on my area of the site regarding service clashes, particularly drainage.
A 3D model was constructed for the building – clash detection was said to be acceptable. Foundations were constructed by another contractor on a contract with the Principal Contractor. The modular building contractor approved the as built strip founds by survey prior to beginning install of the modules stating that the greatest disparity in the service pop ups was +/- 40mm.
The intent was for vertical soil stacks to connect directly into the waste pipes from WCs in the corners of each unit. This did not account for the steel plate in the corner of every unit to allow attachment of plasterboard or for certain units to have their beams sit directly on top of the service pop ups. I advised (as PC we can’t do anything else) that they cut holes in the plate, as they were going to install a series of flume like bends which would mean additional boxing in. It also meant the plumbing sub contractor taking on risk from straying from the design which was unfair on his part.
Also, I think John mentioned always to check cross-sections rather than just look at plans. I have seen this first hand as a kitchen extraction duct is being installed that allows only 2.2m headroom, not including a floating ceiling to be installed. The spin off from this is that if this duct is not changed it creates a ceiling void above 800mm depth, thereby requiring fire detection or sprinklers. The duct also (as everyone who has seen it agrees) looks odd. Which has been enough to get the designers down to have a look this week. The duct is extraction for a reheat kitchen, yet it is twice the size of the same piece of kit for a proper kitchen in an adjacent building. Maybe a spec issue or stray decimal point.
The M&E, although not what I wanted to be involved in, has been an education in project life cycle and the importance of understanding what drainage goes where prior to casting concrete, signing off surveys, properly visualising the end result of an asset or committing to a design in the case of the extraction ductwork. With time pressure it is not as easy to be as thorough in some areas viewed as less critical but it is often the details that cause bigger problems from what I have seen over the past 7 weeks.
Hoping to get mud on my boots soon or at least within touching distance of a bit of plant (within the safe zone, having filled out the requisite forms etc).
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Soil pipe – oh dear (or no no not again). That’s definitely and E&M sized piece of duct. Plenty of space and scope for change. Probably sized ready for an architect to demand it is made smaller, and yet the request never came…
I went for a look today and the plumbers have changed the diameter of pipe that feeds it as it is just for urinals. Which I thought seemed ok.
The change didn’t go down well in the office as it was a design change that the contractor didn’t go through the proper process for.
I would have thought they would have used a standard pipe reducer, which is not a design change if it is the interface between plumbing and drainage. The only thing that must be checked is that this is not the head of the run or, if it is, that there is some form of air admittance.
I mentioned that also, but they still view it as a change to what is represented in the drawings.
Hopefully a spec issue with the duct work although apply absolute worse case criteria to an area with the word “kitchen” and you can quite easily get to 0.8m^2 for a 12 x 3.6 x 3 room.
I’ll caveat that by saying apply absolute worse case criteria without thinking about what your doing ……… guess the installers were wringing their hands putting it in, knowing they’ll be back in to replace it.
Interestingly the clash detection checks didn’t go further to a common sense check!!!
There is another extraction duct actually within the kitchen that is being replaced next week for a shallower one but the same width. Suggesting spare capacity or over design.
Dan,
I managed the installation of a much smaller office at my site (96 units over 3 storeys). It seems like they had a different approach though – design no drainage at all initially. This meant that I had to design it at the last minute. It was made a much simpler task by having all of the plumbing pre-installed (surely one of the main benefits of modular construction?) and all I had to do was pick up the penetrations through the walls. Only one area needed to drop through the floor.
How many cabins have you got and how long is your fit out programme?
There are 266 cabins, the fit out is due to complete in the first half of August. Fit out began a month ago. Unfortunately as PC I’ve probably not had the same experience as you in terms of management. The method of drainage you ended up doing seems more convenient although I’m not sure that it would work on this building due to the amount of IT and other services required. the building also has to be dismantled and used again at another site in 10yrs time.
Dan,
That kitchen extract duct is amazing. Are you sure its not a fire escape or a tunnel to a secret nuclear bunker?
We recently did an extract for a 7-storey apartment block that was 600 x 400, looking at the scale next to your door your kitchen extract is bigger than that.
Someone was getting commission from the ductwork installer I reckon.
MP
Mark,
I’m not on this part of site anymore but went in for a look today. The rep from the design company came and head scratched then went off to respec it. It’s being taken down and replaced.