Free Software for Sprinkler Hydraulic Calculations by Alan Ashfield

Reviewers part of AACALC7

Sprinkler Companies

Obviously, AACALC7 can be used by all sprinkler contractors, designers and installers to carry out the full hydraulic calculation of Ordinary / High Hazard fire protection systems to the BSEN and similar rules. It would be their responsibility to layout the pipework and heads to suit the building and it's other services to match the type, height and arrangement of the goods being protected.

The procedure up to now is that such computer programs produce their results in the form of various tables as stated in those sprinkler rules which are then printed out and posted, together with the manually or CAD produced drawings and associated information, to the appropriate Reviewing Authority. Recently those organisations have chosen to receive that data in the form of PDF files, knowing that they can and do, potentially contain viruses which must be scanned for.


With AACALC7, this procedure can be enhanced by just transmitting the DXF drawing + AHR file (if directly from CAD) or the hydraulics AHC file (if doing the calculations separately from the drawing). With the former, I have made the reviewing process very easy as a separate "Reviewers" part just shows :-

Example of Reviewers screen

Note how I have reduced the operation of AACALC7 to just clicking on 6 buttons (2 of which are "Help" and "Close") - I really cannot make it any easier!

If the contractor sends their hydraulic calculations file(s), then the Reviewer can just use all the various features of AACALC7 to select, calculate and view the results, just as the originator did in their design office - you MUST get the same answers because you are both using the same program, hydraulics data file and pipe types/sizes/fittings database which only I can revise. So the screen you would view would look like :-

Example of job screen


However, I have always been concerned that we are not using the computer for what it is good at - repetitive calculations. Up to now, one has just prepared the data for two design areas in any one installation - called the most remotest and the most favourable - and ensured that the pipe / head sizes, pump / tank details etc. were satisfactory for these two conditions. What if the "fire" occurs somewhere else?

Another problem overlooked by some reviewing authorities is that these two sets of calculations are carried out when there is NO water in the system - on the Qcap/Qmax graph the MR / MF design areas must be at least half a bar pressure BELOW the minimum level of water in the storage tank! So when one carefully considers all the flow, pressure, velocity and density calculations given by the (usually mine) computer programs since 1985, they should all say ZERO! I therefore have a better idea which is included in this version of AACALC7.

If the sprinkler contractor enters all the pipes and heads for any complete installation / building and sets out a suitable pump / tank set, then one can simply move a design area (of set square metres and shape) anywhere on the plan view :-

Move the purple square

With just one click your mouse, the two sets of hydraulic calculations are balanced to the pump / tank set defined and a summary is shown, with the densities of coverage at the operating heads given in green :-


You will note the "Results screen" is in two parts :-

One can then move the square / rectangle representing the design area somewhere else on the drawing, click again and see another summary within 1 second!

Another design area

So one can try along the edges, in the far corner, next to the control valves, right in the middle and so on in a few minutes at most to consider the WHOLE scheme.

If you want to try this out yourself, select the 7th demonstration job (called Gridded Example) to see the noded up isometric view on the screen. Now choose "Reviewer" and select the second "Files of type" option (called Certain hydraulics files) and click on ALANSDEMO7.AHC and then "Open". You will then see a new screen so just select "Show plan and then select heads to calculate" to view the plan and a purple square you can move around - just click at any convenient point - and again and again until "Stop".

Isn't this better? There is no need for ANY separate MR/MF calculations to be carried or assessed by the contractor or the reviewer and one can dispense completely with the Qcap/Qmax graph (Where did the square law flow axis come from? Where did the half a bar allowance come from? No, this graph just cannot be right!). Surely this will make the designers task easier and the reviewers can assure themselves that the complete sprinkler system is satisfactory without pouring over reams of (currently) meaningless numbers! Just an idea - forget it if not appropriate.

Program features

Typical view

May I quickly summarise the features of AACALC7 that may be of particular interest with reference to the above picture :-

I hope you find this all of interest and can find the time to evaluate the FULL FREE program. My contact details are in the "Help" section of the program for security reasons.