i think what confuses some people (including myself for awhile) is the total demand fixture units and the individual fixture supply fixture units and how theyre summed up to calculate fixture gpm. because to the naked eye, you size a tub/shower as 4 fixture units on each line except it only counts as 4 total demand because the gpm off the fixture can only produce 4 fixture units of the mixture. so technically you size each line as if it would require 4 units, for hot, and 4 units for cold. but total demand is only 4 because only 4 units can come out of the fixture. the reason you want 4 units demand minimum for each line is because there are rare people that use only hot or only cold and that would meet the need of the demand of 4 fixture units for one line. but no matter what, the demand for a fixture will never exceed its total gpm rate. so when youre sizing total demand you will never exceed the initial supply demand you sized the house for. when you branch off for the water heater, it is very tricky not to add an excessive amount of fixture unit counts to your demand but be careful because you are only sizing the branch lines to handle that extra demand if only one line is being turned on, and not adding the amount to the fixture count initial supply demand. hope that makes sense
Can you teach how to do the optional method load calcs for single family dwelling and multi family? seems like no one on youtube has in depth really covered it.
![[ ออกกอง ] วัยหนุ่ม 2544 โลกหลังลูกกรง..ทัวร์กองถ่ายหนังใน "คุกของจริง" | JUSTดูIT.](http://i.ytimg.com/vi/vB--aOkZCpw/mqdefault.jpg)
i think what confuses some people (including myself for awhile) is the total demand fixture units and the individual fixture supply fixture units and how theyre summed up to calculate fixture gpm. because to the naked eye, you size a tub/shower as 4 fixture units on each line except it only counts as 4 total demand because the gpm off the fixture can only produce 4 fixture units of the mixture. so technically you size each line as if it would require 4 units, for hot, and 4 units for cold. but total demand is only 4 because only 4 units can come out of the fixture.
the reason you want 4 units demand minimum for each line is because there are rare people that use only hot or only cold and that would meet the need of the demand of 4 fixture units for one line. but no matter what, the demand for a fixture will never exceed its total gpm rate.
so when youre sizing total demand you will never exceed the initial supply demand you sized the house for.
when you branch off for the water heater, it is very tricky not to add an excessive amount of fixture unit counts to your demand but be careful because you are only sizing the branch lines to handle that extra demand if only one line is being turned on, and not adding the amount to the fixture count initial supply demand.
hope that makes sense
very helpful video!
do you have a video on upc plumbing fuel gas pipining sizing
Can you teach how to do the optional method load calcs for single family dwelling and multi family? seems like no one on youtube has in depth really covered it.
Ask and ye shall receive! I just uploaded the optional method video here th-cam.com/video/l6BSNCbgL4k/w-d-xo.html