The Study Of Probability Calculation Method Of Design Flow Rate For Domestic Drainage

Currently the methods of design flow rate for domestic drainage which are popularly used in the world include square root method, experience method and probability method. That the study of applying probability calculation method to determine the instantaneous peak of design rate for domestic water supply has becomes worldly trend. As domestic economy has been rapidly developed, the study of probability calculation method of design flow rate for domestic water supply, hot-water supply and piping drinking water supply has some achievements. It's unreasonable that the design flow rate for domestic water supply is based on probability in the Design Code (GB50015-2003) while drainage is still based on the formerly square root method.The process of supplying water is a random variable that the use of sanitary wares has no influence on the one anther, so does domestic drainage. So, it's reasonable to employ probability method to describe the process of drainage. And drainage has its peculiarities such as quickness, tremendous instantaneous flow, and long interval before another drain and irregularly, it should have different formula.Based on the study of calculation method of design flow rate for domestic drainage abroad and home, this thesis explores a new formula on the basis of probability method, which considerate all the influencing factors on the drain flow and combines our country's traits. This subject contents:(1) Analyzing and comparing the outcome, characteristic and the disadvantages of the calculation method of design flow rate for domestic drainage among our country, USA, Germany and Japan.(2) According our people's customs, calculate the frequency of the use of different sanitarywares in different rank of houses in the rush hour by the water usage criteria.(3) Reckon the relationship between draining equivalent N_p and the design flow rate for domestic drainage qp under different probability by programming.(4) Considering all the parameters and factors that affect the calculation method of design flow rate for domestic drainage, form a U₀—N_p^q_p chart that unite the water supply and hot-water supply formula ,which engineers can consult conveniently.(5) Drawing the list that recommended to be written in the Design Code about the calculation method of design flow rate for domestic drainage.