Home > Uncategorized > The blind leading the blind.

The blind leading the blind.

I have now started my design attachment in the USACE’s Baltimore District Headquarters and am currently working on two projects. One of which is a ‘server room’ cooling survey at Fort McNair in Washington DC, which this blog will focus on outlining.

Fort McNair, in the heart of Washington DC. As you can imagine the traffic was delightful.

Fort McNair, in the heart of Washington DC. As you can imagine the traffic was delightful.

I have realised my utility, I am cheap, and so have used this to secure some responsibility early. The project budget is $50,000 and, in the mechanical section, the average engineer’s time is billed at $135 per hour. The basic sum on this gives an engineer 370 hours, but add in project manager time, vehicles and other overheads and it can soon be eroded. This is something I will research into for a further blog but the upshot is that this is now my project, and a handsome little mess it looks like to. The scope of the work currently is to write a report on the cooling within a number of server and communication rooms within the Military District of Washington (MDW) office buildings. There are 15 different rooms spread across 8 buildings, built circa 1900, all with vastly different loads and in different conditions.

After meeting with the USACE project manager, the client and the HVAC engineer for the buildings, Don Ruhl (my partner from the mechanical section) and I toured a number of the rooms. As we travelled around it became apparent that not only did the client not know what they wanted; they also didn’t know what they had in the rooms. The photos give an idea of a couple of the rooms and the varying conditions.

Don inspecting the many unsealed penetrations in a small converted basement broom closet. This room had about 12U of switches and had a retrofitted ductless cooling system. It also had a condensate drain to a sump, thus allowing the condensate to re-evaporate and continually cycle through the cooling system.

Don inspecting the many unsealed penetrations in a small converted basement broom closet. This room had about 12U of switches and had a retrofitted ductless cooling system. It also had a condensate drain to a sump, thus allowing the condensate to re-evaporate and continually cycle through the cooling system.

Another basement room with abandoned hardwiring to the Pentagon. About 45U of high grade servers in here. The pipe on the floor is for chilled water with heavily damaged insulation allowing condensate to form on it in the summer.

Another basement room with abandoned hardwiring to the Pentagon. About 45U of high grade servers in here. The pipe on the floor is for chilled water with heavily damaged insulation allowing condensate to form on it in the summer.

Server rooms are ideally internal within a building in order to avoid solar heat gains and also because servers don’t need a window to stare forlornly out of. They are usually sealed from infiltration; tidy, to control airflow and have some form of HVAC. The current standard for low and medium density data centres and server rooms is to use a hot aisle, cold aisle system as illustrated below. Cold air is fed from low down in the ‘cold aisle’, either through the floor or by retrofitted ducts; the server blade draws it in through the front and rejects warm air through the rear into the ‘hot aisle’. This rises and is collected by the return air system. As the photos above indicate this was not the case.

Hot aisle, cold aisle process diagram.

Hot aisle, cold aisle process diagram.

So what. Well given the conditions in many of the rooms, even doing a complete survey would be incredibly costly on time. After this initial assessment we need to engage in some expectation management in what we will be able to provide and re-write the scope of our work, which is currently pretty open ended. I see this largely as focusing effort on the more important rooms in terms of upgrades and identifying the risks of each room to the client so that they can make an informed decision.

Screen Shot 2015-11-11 at 11.50.06

In an age of BIM, I have been told that the best we can get is a floor plan for some of the buildings so it appears that even a set of out of date as built drawings are a wish too far. Due to this if construction work is ever completed on this then the contract will almost certainly have to be a design and build as the potential for change orders on a traditional contract would be immense!

Finally, a little leadership challenge.

I mentioned earlier that I had been given the lead on this project but I am working with another engineer. Don has worked for USACE design section for at least 30 years and is probably the most intelligent person I have met out here. He has no aspirations of leadership and is very happy to let me control things; however his ability to take a tangent and dive too far into the details too early are something to behold. Certainly a different management challenge from both soldiers and contractors!

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  1. Rich Garthwaite's avatar
    Rich Garthwaite
    11/11/2015 at 4:59 pm

    Henry, Excuse my ignorance but what is a U?

    • 12/11/2015 at 2:33 am

      Rich,

      Sorry, should have expanded that out. A ‘U’ is basically the unit of height of a server in a data rack. It is about an inch and server equipment is specified in “U’s”. Clearly although it sounds like a nice standardised system, there are plenty of variations too.

      • Rich Garthwaite's avatar
        Rich Garthwaite
        16/11/2015 at 2:05 pm

        Cheers.

  2. Fran Rizzuti's avatar
    Fran Rizzuti
    11/11/2015 at 10:07 pm

    Henry,

    Interesting challenge you have there. Not sure if you read my blog about chilled water from CEP; it also contains a brief description of our main communication room and the same ‘hot aisle’ principle. Though I must say looking at your photos you’ve got a lot of work to do in sorting that lot out.

    What type of fire suppression system is currently installed and do you have plans to revamp them throughout?

    Also, is your cooling

    • Fran Rizzuti's avatar
      Fran Rizzuti
      11/11/2015 at 10:15 pm

      Sorry Henry, fat fingers using iPhone…

      Also, in order to cool each room is the design intent to use the hot aisle method (which am I right in saying is supplied from the main ducted air handling units) or is that just for the main Comms room?

      This is what we have on-site with the individual floor Comms rooms being cooled by CRAC Units – basically a standalone AHU specific to that room. This then only relies on chilled water to be piped around the building to each CRAC Unit rather than lots of more expensive bulky ducting.

      • 12/11/2015 at 2:49 am

        Fran,

        I imagine/hope this is significantly more agricultural than in your new hospital! The largest server room is served well by dedicated CRAC units and fire suppression. As the CRACs were small and retrofitted they weren’t served by the building’s chilled water, instead they were essentially a split AC unit in that the piping to them was for a remotely sited condenser. I couldn’t take pictures of these as it was ‘secure’.

        The others will require cheap bespoke systems, the largest will perhaps have a proper CRAC. If so I imagine we’ll aim for a separate condenser again rather than the central chilled water system in order to reduce the risk on having to tie into and then rebalance that system. I anticipate the others will either be served well enough by increased ventilation or by being left alone.

        As for fire suppression I will have to look into the code. I am assuming that it is primarily in order to preserve the equipment and data so I imagine the client would be happy to let it burn.

  3. 12/11/2015 at 8:09 am

    Looks like a good old fashioned birds nest of services to sort out, hopefully there’s a good relationship with the IT/comms departments?

    I’m happy to see that you have to deal with people that take a tangent and dive too deep into the detail too early, welcome to our world 🙂

  4. coneheadjim's avatar
    coneheadjim
    12/11/2015 at 8:31 am

    Henry, you are starting to enter the murky world of FM where there are never any as built drawings and what was once a nice simple design has been messed about with for twenty years resulting in a mess even Albert Einstein would have trouble getting his head round. Take careful notes; these sites seem very representative of the MoD estate.

  5. 12/11/2015 at 8:53 am

    I am sure you will get a lot of valuable experience from this project.

    • 12/11/2015 at 2:00 pm

      Thanks to the drift (collective noun for lecturers) for the comments. It certainly looks like there is both engineering and management experience in this. The IT/comms department rep appeared to view us as a bit of an inconvenience, though I’m assuming it was because he was slightly embarrassed at what he was showing us and had no answers to our questions. I fear that ultimately our solutons will end up being another sticking plaster onto the gaping wounds of the buildings.

      I’d not thought back to the MoD estate but you make a very good point Jim!

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