BS 9251 : 2014

BS 9251 : 2014 - Maximum flow demand calculation

This graphic style is based on Annex C.5 in BS 9251:2014 maximum flow demand calculation. With the correct data input in to spkGraph it will automatically calculate the maximum flow demand point for the system (QMAX) based on the most favourable area demand point and the height of the highest sprinkler. You can also display the most unfavourable area demand point.

The graph is displayed with a flow axis scale being graduated to the square law.

You will need to enter a minimum of three data points for the water supply curve before spkGraph will draw a curve but the more data points you can add the more accurate the water supply line will be and the QMax calculation will be.

If you notice one of the data points is slightly above or below the water supply curve, this is because spkGraph will interpret the data points you have enter and draw a smooth curve (best fit) between points. If you notice that one of the points looks to be inaccurate and it is probably worth checking the data you have entered.

Most favourable area (MFA)

spkGraph will automatically determine the intersection point between the system demand by and the water supply curve and will give you maximum flow demand the system (QMAX).

You will need to supply the most favourable area the source pressure and flow together the height a high sprinkler the same area. In the example below we have used 3.000 m for the height of highest head 200 L/min @ 2.3 Bar and the Maximum flow demand has been calculated to be 233 L/min

Most remote area (MRA)

spkGraph will also display the most remote area the demand point if you enter the demand points pressure and flow. In the example below we have entered 150 L/min @ 2.5 Bar