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Demand Unit Calculation

Demand Unit Calculation

Demand Unit Calculation

(OP)
Please anybody can tell me what is the meaning of " Sink, 20mm sep./mix tap" regarding to Loading unit(Demand Unit) Calculation.

Reference: Plumbing Engineering Services Design Guide, Page 13

RE: Demand Unit Calculation

err what is says? A sink with a tap, either separate hot / cold or a mixer unit fed by a 20mm pipe??

You might get a better answer in the plumbing forum....

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Demand Unit Calculation

(OP)
Thx for replying LittleInch , but when we are go through Demand load calculation by using Simultaneous demand-base data theory (Which I hve attached as jpg file) I feel its not just saying 20mm pipe Outer diameter(as example) . It may be the pipe connector diameter. (I'm not sure about that). I want to know actualy it refers just pipe as you say and also want to know whether it is outer diameter or internal diameter.


RE: Demand Unit Calculation

To how many decimal points do you wish to calculate this value? This is a seeing the forest vs. the trees issue.

Piping Design Central

RE: Demand Unit Calculation

(OP)
Mr Gator thx for replying me, I'm beginner for this industry
Actualy For Loading Unit Calculation we need following parameters
Capacity,Flowrate,Demand & Frequency.For getting the proper idea I asked this question from well experience persons smile2.
But when Consider about types of sinks there are siks such as Kitchen sinks, Hand wash sinks etc. So I want to Clarify as example "Sink, 15mm sep./mix tap" what are the things present in this Phrase and how to relate this diameter to kitchen sink or other type of sinks (i mean is it diameter of the pipe or other item).
thx

RE: Demand Unit Calculation

Do you not trust the advice/experience of your mentors/more experienced coworkers or have they left you alone with this little project?

Piping Design Central

RE: Demand Unit Calculation

Agree with Gator, where are you mentors? They should be helping/guiding you through the design process of designing domestic water system.
Second, you would get more and better responses if this was posted in the Plumbing section.

Now about your questions.
1) It doesn't matter what type of sink (kitchen, lavatory, etc.). It is up to you to determine which row you use based on the sink you are specifying/selecting.
2) 20mm/15mm is referring to the faucet connection size.
3) Pipe sizes always reference the interior diameter. Note that this dimension is nominal, actual internal diameter is never this dimension exactly and varies depending on pipe material and gauge (wall thickness). There are various resources to get actual inside dimensions if you really need.
4) Sep./mix tap means that the fixture has 2 points of connection (one for hot water, one for cold) and the water is mixed internally in the faucet. Go to your local hardware store and take a look at the faucets on display.

Since the provided table does not include fixtures like water closets or wall hydrants, I assume it is referring to hot water demand values. In which case, capacity, flow rate etc. would be for the hot water side of indicated fixtures only. Read through the book (I know it's a foreign concept) you should find explanations for the table's content and how to use.

Being in the USA, I am used to working with "fixture units", a figure used in conjunction with Hunter's curve to estimate demand flow rate in gpm. The "Demand Unit" I assume is the SI equivalent to fixture units and be used with a SI calibrated Hunter's Curve (unless it goes by another name), consult with your mentors. Here in the USA we mostly use ICC IPC or some derivative which provides a tabulated form of Hunter's Curve.

RE: Demand Unit Calculation

(OP)
Thank you very much for your replies. And specially dbill74 & bimr thank you both of you again

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