The flow time and total method requires the cumulative total over the time period and uses the flow time to determine the average.

The other methods are for use where the flow is different but constant at two separate time intervals within the selected period. The average is calculated using the set 1 and set 2 flowrates with reference to either the total elapsed time or samples. The averages can be formatted as flow per day, per hour, per period A or per period B.

One of the following calculations are carried out for each flowrate depending on whether the flowrate is mass based, gross volume based, standard volume based or energy based.

Symbol | Description | Units |
---|---|---|

Inc_{1} |
Increment for data set 1 | - |

Inc_{2} |
Increment for data set 2 | - |

Q_{v,1} |
Gross volume flowrate for data set 1 | m^{3}/s |

Q_{v,2} |
Gross volume flowrate for data set 2 | m^{3}/s |

Q_{s,1} |
Standard volume flowrate for data set 1 | Sm^{3}/s |

Q_{s,2} |
Standard volume flowrate for data set 2 | Sm^{3}/s |

Q_{m,1} |
Mass flowrate for data set 1 | kg/s |

Q_{m,2} |
Mass flowrate for data set 2 | kg/s |

Q_{e,1} |
Energy flowrate for data set 1 | |

Q_{e,2} |
Energy flowrate for data set 2 | MJ/s |

q_{v,TWA} |
Gross volume flowrate time-weighted average | m^{3}/s |

q_{s,TWA} |
Standard volume flowrate time-weighted average | Sm^{3}/s |

q_{m,TWA} |
Mass flowrate time-weighted average | kg/s |

q_{e,TWA} |
Energy flowrate time-weighted average | MJ/s |

One of the following calculations are carried out for each flowrate depending on whether the flowrate is mass based, gross volume based, standard volume based or energy based.

Symbol | Description | Units |
---|---|---|

q_{v,TWA} |
Gross volume flowrate time-weighted average | m^{3}/h |

q_{s,TWA} |
Standard volume flowrate time-weighted average | Sm^{3}/h |

q_{m,TWA} |
Mass flowrate time-weighted average | kg/h |

q_{e,TWA} |
Energy flowrate time-weighted average | GJ/h |

Q_{v} |
Gross volume total | m^{3} |

Q_{s} |
Standard volume total | Sm^{3} |

Q_{m} |
Mass total | kg |

Q_{e} |
Energy total | GJ |