#GALLONS PER DAY ENGINEERING CALCULATOR CODE#

This figure is used to size the building main, what connects to the street and what the project's civil engineer needs. (The building will NOT use 650 GPM 24/7.)Ī: Yes and no. Pedarrin mentioned using a diversity factor or 70-80% IMHO this wuold probably be good for up to about 100 bathroom groups, for 382 bathrooms I think a better diversity factor would be closer to 45-50%.Ī: It is the peak demand at any one time. This takes into account that with more fixtures in a system, the diversity is going to go down.

Do a goolge search for Hunter's curve and look at the images that come up, it is not linear. Keep in mind that when using fixture units and the Hunter's Curve, there is a built-in diversity factor. I have to admit I find it hard to believe UPC and IPC would generate such a large difference. You mention getting a range of 300-764 GPM at one point. I am curious to see your calculations Mech110. RE: Water demand using UPC and other approaches Mech110 (Mechanical) My water supply fixture load was 8633 and my domestic water service was 8', so a higher peak flow rate (~800 gpm) is not out of the question. I had a hotel I designed that had ~530 rooms, three restaurants, a pool, and other associated items. I would hesitate to use it for a larger situation because I don't know that it would just be a multiplication factor. The IAPMO (which is the base organization which publishes the UPC) publication is for residential (single and multiple (4 max?) family dwellings.

#GALLONS PER DAY ENGINEERING CALCULATOR CODE#

The reason in my opinion the UPC and/or the IPC are silent is they are code, not engineering design guides (mostly) The UPC (which I don't use much as I work in IPC areas) includes water pipe sizing in the actual code whereas the IPC has it in an appendix.Īnd the ASHRAE modified curves are for hot water only and are used to calculate a balance between hot water generation and storage, but really have nothing to do with flow. I typically size water storage by the published gpd of facilities and add ~10% for safety factor. Unless you have meter information from a similar installation, you will likely ovesize the storage. Sizing water storage, however, should not. In my opinion, pipe sizing should be based on the max of these two flow rates. sporting event or convention center type use, which might be used in a fairly short period of time, you have to take that into account because it could make your Hunter's curve peak load too small. I don't know what a 3B+G+9 commercial+residential building is specifically, but if you have a lot of showers which might be used early in the morning, or if you have a lot of large toilet rooms, i.e. However, you need to consider the type of facility. I usually calculate the flow rate per the Hunter's curve, then use a factor of 0.6 to 0.7 to account for these changes. They still flow ~25 gpm, but the gallons per flush has decreased. But with the exception of toilet room lavatories and showers, the flow rates have not changed, just the flow duration, i.e. Then there is the issue of lower flow fixtures. But it takes money to fund studies and that has not been forthcoming. The Hunter's curve is what was and still is utilized.īut in many people's minds, it is overly conservative and there has been a push to refine or revise his approach due to better knowledge of the statistical use of fixtures. In the US, it is based on studies performed by Dr Roy(?) Hunter in the early to mid 20th century. Typically water supply demand calculated by methods in plumbing codes are peak demands which does include statistical diversity. I would recommend looking at ASPE (American Society of Plumbing Engineers) documents/references. Thanks in advance! RE: Water demand using UPC and other approaches PEDARRIN2 (Mechanical) 10 Jul 18 10:36

Why SO MUCH difference in these approaches? Which approach should be used then? is UPC ok? safe? 650 gpm ok?

Similar is the case of using any other approach like area density or per unit dwelling quantity. If I use average daily consumption of water per person (100 gallons per person per day), the water demand is too lower than 650 GPM. Pipe sizing and water tank sizing should be based on directly this figure 650 GPM or something else has to be done?ģ. What does this figure of 650gpm calculated from UPC represent? Is this average demand of the building per minute or peak demand at any one time? does this also include diversity factor?Ģ. I have been reading a lot of articles and discussions on this forum as well as other sites. I calculated from UPC 2015 total fixtures 5815 which translates to 650 GPM. I am calculating water supply demand for a 3B+G+9 commercial+residential building.

Gallons per day engineering calculator