What is Normal, High, Low Flow in Fire Pump

[DJVS]

Kindly explain me the following fire pump schedule.
What does it mean by Normal, High, Low Flow.

Thank you for your valuable time.

 

[chicopee]

Please see the attachment that shows the probable electric and diesel pump delivery curve from data that you posted in your OP. Now, I am not sure where these so called fire pumps were tested but their graphs are not consistent with rated horizontal shaft and vertical shaft turbine fire pumps used in the USA whose curves are shown and the right hand side of the attachment.