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What MIC would you expect to for a building with 5 electric showers

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  • 23-10-2020 3:02pm
    #1
    Calahonda52
    Registered Users Posts: 12,240 ✭✭✭✭


    Building was built in 1994, 5 elec showers, all can be in use at the same time.
    MIC on bill in 19 kVA
    That make sense?
    Thanks as always
    I don't have the wattage on the showers

    “I can’t pay my staff or mortgage with instagram likes”.



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    #2
    Lenar3556
    Registered Users Posts: 1,359 ✭✭✭Lenar3556


    Depends on how you would treat 5 showers in terms of diversity. If by design all 5 are anticipated to operate simultaneously then your MIC would theoretically need to be at least twice what it is.

    However that is likely to be considerably more expensive, and given the relatively poor performance of electric showers, I would consider power showers run from the likes of a gas powered Rennai water heater as perhaps a better alternative.

    Incidentally, things were done a little differently in 1994! If the ESB supply is performing without issue, the proof of the pudding is in the eating and I wouldn’t interfere!


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    #3
    antoinolachtnai
    Registered Users Posts: 9,776 ✭✭✭antoinolachtnai


    Good advice here.

    What fuse has ESB fitted? Is this a single-phase or three-phase installation?

    Is the DG on the bill DG1, DG2, DG5, or something else?

    You sometimes can’t read too much into the nominal MIC on the bill.


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    #4
    Calahonda52
    Registered Users Posts: 12,240 ✭✭✭✭Calahonda52


    Thanks guys, its a fire station and they want to replicate it across the pastime stations and get rid of the immersion cylinder.
    There is no gas on site, only oil so is there an oil equivalent
    Its DG5 MCC01 Profile 05

    Don't know re the 3 phase
    Thanks again.

    “I can’t pay my staff or mortgage with instagram likes”.



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    #5
    antoinolachtnai
    Registered Users Posts: 9,776 ✭✭✭antoinolachtnai


    Calahonda52 wrote: »
    Thanks guys, its a fire station and they want to replicate it across the pastime stations and get rid of the immersion cylinder.
    There is no gas on site, only oil so is there an oil equivalent
    Its DG5 MCC01 Profile 05

    Don't know re the 3 phase
    Thanks again.

    It might work in a fire station because the use of the showers won’t all be used in a short time period.

    But it doesn’t seem like a setup to be replicating. It really depends on what sort of ESB connection there is. It would be very hard to stand over.

    You have to have continuous power in a place like a fire station for all sorts of reasons. Anything that risks blowing the ESB fuse really shouldn’t be on the menu.

    If I was in charge of having happy firemen I would want a proper pumped shower for them.

    Stored water would seem like the most reliable solution. If they use a lot of hot water, solar is likely to make sense for a large part of the year.

    I can see why it might be attractive for a part time station I suppose and maybe the problem with fuses wouldn’t be so critical. I still think they’d be better off with a tank and set it up somehow so that the water started heating automatically when the fire engine left the station or something!


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    #6
    Calahonda52
    Registered Users Posts: 12,240 ✭✭✭✭Calahonda52


    There are new regs, non covid, in now where they have to wash all their kit at the station and shower before they home, due to risk of carcinogens, especially from house fires, so all the showers get used at the same time.

    “I can’t pay my staff or mortgage with instagram likes”.



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    #7
    Lenar3556
    Registered Users Posts: 1,359 ✭✭✭Lenar3556


    The likes of a 70kva 3PH supply is what you would be looking for to reliably replicate that.

    But a 600l rapid recovery cylinder, supported by a 40KW oil boiler would leave a much more satisfactory solution, because you can have a pumped system with much better hot water flows.

    The heat loss from factory insulated cylinders is small, so I’d have it up to temperature all the time as an independent zone from the oil boiler.


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    #8
    antoinolachtnai
    Registered Users Posts: 9,776 ✭✭✭antoinolachtnai


    Calahonda52 wrote: »
    There are new regs, non covid, in now where they have to wash all their kit at the station and shower before they home, due to risk of carcinogens, especially from house fires, so all the showers get used at the same time.

    Then the cylinder is the way to go. Much more straightforward. You can have a number of elements and another heat source (like oil as mentioned) to protect against failure of an element. It’s all very standard and easy to service. By the time you add everything up it might be as cheap or cheaper.

    Do you need to keep the water hot all the time? That is the place where there are some savings to be made really. I wouldn’t be shy about making the tank large. If they have laundry the hot water setup may be useful for that too.


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    #9
    Calahonda52
    Registered Users Posts: 12,240 ✭✭✭✭Calahonda52


    Thanks, the issue is in part that they have this legionella protocol where they run the hot taps for x minutes every so often, the water is never above 55 so pointless: the tank gets emptied!
    Anyway thanks for your insights, will talk to them!

    “I can’t pay my staff or mortgage with instagram likes”.



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    #10
    ted1
    Registered Users Posts: 23,322 ✭✭✭✭ted1


    You are looking at 45kW which is a large load. Talk to the SEAI you may be entitied to a decent grant for a solar system PV wouldn’t work , but solar tubes or a flat plate (maybe geothermal ) will heat the water over the Course of the day.

    Even possible replace Oul with Gas, electricity is the dearest way to heat water


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    #11
    antoinolachtnai
    Registered Users Posts: 9,776 ✭✭✭antoinolachtnai


    Calahonda52 wrote: »
    Thanks, the issue is in part that they have this legionella protocol where they run the hot taps for x minutes every so often, the water is never above 55 so pointless: the tank gets emptied!
    Anyway thanks for your insights, will talk to them!

    You can set up the cylinder to go to a higher temperature for the legionella thing. You can also have a ring with circulating pump which will allow everything except the actual taps to be heated to the higher temp without running the water. Whether this would be acceptable for their protocol, I don’t know.


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    #12
    Calahonda52
    Registered Users Posts: 12,240 ✭✭✭✭Calahonda52


    Thanks, will explore this.
    In passing, is it possible to tell from a bill if the site is 3 phase.
    The big users such as leisure centres are on a separate account where they are all 3 phase, but I have 300 odd sites in another account, including th stations, so just wondering if I can tell

    “I can’t pay my staff or mortgage with instagram likes”.



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    #13
    antoinolachtnai
    Registered Users Posts: 9,776 ✭✭✭antoinolachtnai


    Calahonda52 wrote: »
    Thanks, will explore this.
    In passing, is it possible to tell from a bill if the site is 3 phase.
    The big users such as leisure centres are on a separate account where they are all 3 phase, but I have 300 odd sites in another account, including th stations, so just wondering if I can tell

    If you have the meter RM number, you can kind-of tell. Certain RMs are three phase meters. There is no published list breaking them down by single and three phase however.

    DG6 or higher is always going to be 3-phase.


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    #14
    ED E
    Registered Users Posts: 36,166 ✭✭✭✭ED E


    Curious side issue raised by Antonio, what kind of site reliability issues arise. Tetra can function on handhelds and you'd hope most stations would have coverage to receive an alert that way but opening the shutters, the ability to receive calls from the call takers etc. Are stations gen backed? I suspect they aren't (maybe DFB).


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    #15
    Calahonda52
    Registered Users Posts: 12,240 ✭✭✭✭Calahonda52


    Thanks ED, over my head here now, whats Tetra and DFB?
    I was in one of them when they got called out, the messaging to the guys comes from the centre somewhere, not from the station and they all arrive in their cars/vans/etc:including plumbers/chippies/sparks/painters/ all off jobs!.
    The shutters have chain overrides what what I saw.

    “I can’t pay my staff or mortgage with instagram likes”.



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    #16
    antoinolachtnai
    Registered Users Posts: 9,776 ✭✭✭antoinolachtnai


    Calahonda52 wrote: »
    Thanks ED, over my head here now, whats Tetra and DFB?
    I was in one of them when they got called out, the messaging to the guys comes from the centre somewhere, not from the station and they all arrive in their cars/vans/etc:including plumbers/chippies/sparks/painters/ all off jobs!.
    The shutters have chain overrides what what I saw.

    Tetra is the emergency services cellular radio system.

    DFB is Dublin Fire Brigade I presume?!

    I would be surprised if a crowd of determined fire persons would be deterred by a stuck shutter!

    I imagine comms and so on is a bigger issue for main fire stations.

    I would be worried about managing safety and compliance on a load of remote sites like this. For example if the ESB fuse blows at a crucial time (shower time), what will the crew do? You would like to hope they would call head office or their friends in the local ESBn depot but someone might just decide to replace it themselves. They are a resourceful lot after all and pulling out ESBn fuses is not something new for them. No one can really be held to account if this happens.

    Of course as well as being illegal this is completely unmanageable. You wouldn’t want a situation like this to ever arise.

    If these stations are a bit remote then it will be difficult to get MIC increases.

    By your description I think my idea of triggering the hot water heater when the fire tender leaves the station would be great! Or you could have a big button in a few places that you could press to start the water heating. It’s not instant but it’s not bad.

    You need to automate the Legionnaire’s disease cycle somehow.


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    #17
    Lenar3556
    Registered Users Posts: 1,359 ✭✭✭Lenar3556


    antoinolachtnai wrote: »
    Tetra is the emergency services cellular radio system.

    DFB is Dublin Fire Brigade I presume?!

    I would be surprised if a crowd of determined fire persons would be deterred by a stuck shutter!

    I imagine comms and so on is a bigger issue for main fire stations.

    I would be worried about managing safety and compliance on a load of remote sites like this. For example if the ESB fuse blows at a crucial time (shower time), what will the crew do? You would like to hope they would call head office or their friends in the local ESBn depot but someone might just decide to replace it themselves. They are a resourceful lot after all and pulling out ESBn fuses is not something new for them. No one can really be held to account if this happens.

    Of course as well as being illegal this is completely unmanageable. You wouldn’t want a situation like this to ever arise.

    If these stations are a bit remote then it will be difficult to get MIC increases.

    By your description I think my idea of triggering the hot water heater when the fire tender leaves the station would be great! Or you could have a big button in a few places that you could press to start the water heating. It’s not instant but it’s not bad.

    You need to automate the Legionnaire’s disease cycle somehow.

    I would just have the cylinder on all the time with temperature control. The loss from many of the factory insulated 300l is circa 2KW per 24Hrs. Very small in the context. More reliable than some auto start heating arrangement.


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    #18
    jenneyk19
    Banned (with Prison Access) Posts: 54 ✭✭jenneyk19


    showers are 8-9 kw each

    but you will not run 5 at same time
    you would save money if you used gas to heat water


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    #19
    salmocab
    Registered Users Posts: 11,296 ✭✭✭✭salmocab


    Calahonda52 wrote: »
    Thanks, the issue is in part that they have this legionella protocol where they run the hot taps for x minutes every so often, the water is never above 55 so pointless: the tank gets emptied!
    Anyway thanks for your insights, will talk to them!
    Not sure I’m taking this up right but legionella forms somewhere between 20 and 50. The taps are run regularly to stop it getting into the water that’s stored so doing this is not pointless.


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    #20
    frozenfrozen
    Registered Users Posts: 7,882 ✭✭✭frozenfrozen


    jenneyk19 wrote: »
    showers are 8-9 kw each

    but you will not run 5 at same time
    you would save money if you used gas to heat water

    this is for a fire brigade they would all be using the showers as soon as they get back


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    #21
    antoinolachtnai
    Registered Users Posts: 9,776 ✭✭✭antoinolachtnai


    salmocab wrote: »
    Not sure I’m taking this up right but legionella forms somewhere between 20 and 50. The taps are run regularly to stop it getting into the water that’s stored so doing this is not pointless.

    It’s a while since I looked into this but I would consider this in the design of the system as it is a major consideration. Thermal disinfection may not be all that great and it takes time to do. You will want to get an adequate temperature at all the outlets so you need to design plumbing with this in mind.

    I would be concerned too that thermal disinfection would not be an adequate way to disinfect an electric shower. You will not be able to get the shower to go hot enough. These things are (wisely) designed not to produce scalding water.

    But really you have to do a risk assessment. On the one hand these part-time sites may be unused for periods of time and that may present a risk. On the other hand, fire persons tend to be fit and healthy guys and girls and are not the sort of people typically afflicted by Legionnaires.

    I would really read all the paperwork before making any design decisions. Here is a very technical paper about it which explains requirements for thermal and chemical disinfection. (There are others on the same website that focus more on the risk assessment side).

    https://www.hse.gov.uk/pubns/priced/hsg274part2.pdf


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    #22
    JimToken
    Closed Accounts Posts: 225 ✭✭JimToken


    I thought I read that legionella you had to raise the temp of the stored water occasionally

    Prob draining it off accomplishes the same thing


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    #23
    salmocab
    Registered Users Posts: 11,296 ✭✭✭✭salmocab


    JimToken wrote: »
    I thought I read that legionella you had to raise the temp of the stored water occasionally

    Prob draining it off accomplishes the same thing

    Stored water needs to be over 50 which is easily achieved however the issue isn’t going to be in the tank but rather the pipe work where the temp will be lower. Systems need to be flushed regularly.


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    #24
    antoinolachtnai
    Registered Users Posts: 9,776 ✭✭✭antoinolachtnai


    JimToken wrote: »
    I thought I read that legionella you had to raise the temp of the stored water occasionally

    Prob draining it off accomplishes the same thing

    As I understand it you have to disinfect the system, not the water. The problem isn’t the water, it’s the ‘biofilms’ that build up on surfaces in the plumbing system. Draining the water off will not do anything to the biofilms.


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    #25
    ted1
    Registered Users Posts: 23,322 ✭✭✭✭ted1


    https://www.calorgas.ie/for-business/agriculture/instant-hot-water use gas to heat water


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    #26
    Calahonda52
    Registered Users Posts: 12,240 ✭✭✭✭Calahonda52


    Thanks ted, interesting idea.
    It would mean going from oil to gas for everything in these part time stations but certainly worth a look.

    Hadn't thought about LPG

    “I can’t pay my staff or mortgage with instagram likes”.



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    #27
    antoinolachtnai
    Registered Users Posts: 9,776 ✭✭✭antoinolachtnai


    Calahonda52 wrote: »
    Thanks ted, interesting idea.
    It would mean going from oil to gas for everything in these part time stations but certainly worth a look.

    Hadn't thought about LPG

    You can get these yokes.

    https://www.flexiheatuk.com/product/oil-fired-water-heaters/

    But if it is a part time station and already has oil would you not put in a fast recovery cylinder with a few electrical heating elements? If you turn on the electric and the oil together you’ll heat 600 liters of water pretty quickly. You could probably get this down to 30 minutes from cold.

    I would suggest this because it is basically just standard plumbing. It will work even if the oil breaks down or one element burns out. If it breaks, the chippies and plumbers who work as part time firemen will be able to fix it themselves if they are really stuck.


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    #28
    JimToken
    Closed Accounts Posts: 225 ✭✭JimToken


    Can they do the legionella protocol with cold stored water ?


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    #29
    salmocab
    Registered Users Posts: 11,296 ✭✭✭✭salmocab


    JimToken wrote: »
    Can they do the legionella protocol with cold stored water ?

    Yeah it should be run intermittently and any dead legs should be flushed.
    We usually flush hot and cold taking temps once a month but now with a big empty building We’re doing it 3 times a week. Once a week would be fine but the powers that be want 3.


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