I read NFPA 291 Section 4.9 about flow testing without a pitot gauge, but I do not understand where to get the variables. Can anyone help explain the process a little better to me?
Not sure what your question is,,, But
If a pitot tube or other flow pressure reading device is not available, NFPA 291 does give an option for getting the flow reading without one in section 4.9 Determination of Discharge Without a Pitot. NFPA 291 states a hydrant cap can be used on one 2½-in. outlet while opening and flowing the other 2½-in. outlet. According to section 4.9.3 this can be done because the reading should be approximately the same. However, this is to be done only if a pitot tube or other flow pressure reading device is not available or breaks and should not be considered an equivalent option in place of a pitot tube.
I will post a link to this article
Are you looking for the coefficients? If so, Table 4.7.1. It appears that you are just using the cap gauge to measure the "discharge pressure" you'd normally be reading off a Pitot? So enter the same data collected?
Retrieving data ...