Free Hydraulics Calculations Program FREEHCP by Alan Ashfield


Introduction to FREEHCP - 23rd September 2017 :-

FREEHCP is a completely free Hydraulics Calculations Program for the latest NFPA 13/15 Rules in US. Conventional Units (feet, inches, gpm and psi) for use by sprinkler designers, contractors and installers in America. You simply draw out an isometric layout drawing on the screen or in your Computer Aided Design (CAD) program and enter some data pertaining to each pipe so that the hydraulic calculations of flows, pressures, velocities etc can be worked out to show the graphs and results presentations.

FREEHCP - DEMO 1 calculations FREEHCP - DEMO 1 graph FREEHCP - DEMO 1 results 1

FREEHCP is an easy-to-follow, 3D pictorial, interactive "point-and-click" modern 'Windows' program that can be quickly applied to all your day-to-day projects of Light, Ordinary or Extra hazard, end- or centre-fed pipe layouts, looped, gridded, roof-only or roof-rack (if not the more modern ESFR), spray, deluge, drencher, birdcage, ring-main, hydrant, etc. water based fire protection systems. Heads can also be extended coverage, ESFR, QR, large-drop or open types using Area / Drawing or Room Design methods, with or without velocity pressure calculation at intermediate heads along branch-lines.

When you draw out an isometric (or axiometric or any other representation you choose) then all pipes going upwards (north) on the screen are assumed to be vertically upwards in height / elevation and pipes going downwards (to south on your monitor) will be dropping vertically in height / elevation. All the other pipes will be horizontal or sloping up or down at specified angles. This is much easier to visualise than a purely PLAN view so can be immediately accepted by other members of your design team, especially for multi-level systems in buildings and special risk projects.

Full technical support is offered for free by Email (my address is on the top line) - please put FREEHCP in the "Subject" line (I do have 21 other FREE programs on my website!). Just scroll down this page for more detailed help and information on all the features and options in FREEHCP.

You can just use your existing CAD program, either the excellent free LIBRECAD one, low-cost purchases like TurboCAD or subscription based ones to produce the isometric layout drawing for the project in EXACTLY the same way as you have always done and mark on a few text items adjacent to the pipes. Simply give this file name (DXF not any proprietary formats) to FREEHCP, which will instantly display it on the screen and carry out all the hydraulic calculations completely automatically and allow you to see all the data and the flows, pressures, velocity calculations etc. If you need to make some changes to the sizes, lengths, fittings etc. then just go back to the CAD, revise the drawing accordingly, save it and run FREEHCP again as the add, break, copy etc options (as described later), if used, would mean that your original CAD drawing would get out of step with the calculations.

Alternatively, you can just start from NEW in FREEHCP to enter the project data and then add, break, copy, delete, edit, move etc. the pipe sections to make up the remotest area of operation from the water supply out via the feed- and cross-mains to the separate branch-lines supporting the sprinkler heads / nozzles. Each time you make a change, the hydraulic calculations will be instantly performed by FREEHCP, shown on the screen and a DXF file automatically generated for reading into your CAD program. This is the preferred method of using FREEHCP as it always prompts you what can be done next, so reducing errors, as against drawing pipes in a CAD program, where the checking can only be done when you read it back into FREEHCP.

In both cases, you can view the Water Supply Graph and see all the Results Presentation full size on the screen as well as all the data and the flows, pressures, velocity calculations etc. just by moving your mouse over the pipe of interest or selecting about 30 items to show next to the pipe layout.

In addition, FREEHCP produces a simple text file for Emailing to the Authority Having Jurisdiction (AHJ) containing all the project data, pipes information and the pipe / fittings database so that they can also download FREEHCP for nothing and quickly use it to view all the hydraulic calculations, graphs, results, drawings etc. and get exactly the same answers as you got, of course. This will be far easier and beneficial to them as they get to "see" the drawing AND the calculations rather than static CAD drawings and PDF results sheets. Perhaps they have already found out that PDF files can and do contain viruses so no longer accept them as many Reviewers / Inspectors in the UK and Europe do not.

I also supply 4 DEMONSTRATION examples to get you started and FREEHCP will work on CAD workstations, office PCs or cheap laptops with 1366x768 pixel 11" to 15" screens running all versions of 'Windows' from XP to 10, except RT / 10S.

That's all! No more duplicating all the details already drawn in CAD onto a separate expensive, hydraulics program and spending hours typing in the same information as you have already drawn, adjusting the pipe sizes, lengths, design data etc. and then remembering to pass any different details back to the CAD drawing. All the information needed for the isometric sprinkler drawing AND the essential hydraulics is therefore always in the simple text file within FREEHCP. Think how much easier all this is going to be for all your future jobs, as well as costing precisely zero dollars!

Download FREEHCP from this HTTPS website :-

You can DOWNLOAD THE LATEST VERSION OF MY FREE FREEHCP PROGRAM [23rd September 2017 = 847 kB] now by clicking here and "Saving" it to a suitable folder on your hard disk, such as C:\AA3PROGS or C:\freehcp and then create a shortcut on the desktop or pin it to the taskbar or run it from "File Explorer" as you prefer. If using a Microsoft browser and you get a blue bar across the screen about SmartScreen, click on "More info" and "Run anyway" to download and run this program. Do NOT download it from anywhere else on the Internet, just this end-to-end encrypted website. Note that there is no set-up or install routines to scatter dozens of files all over your disk - just the one, small EXE file.

No doubt you, like me, no longer connect to the Internet with 'Windows 10' due to all the monitoring, tracking, surveillance, key-logging and data retention by Microsoft and their partners, so you may need to download FREEHCP to a much more secure Linux computer / operating system, and then copy it to the Windows XP, Vista, 7, 8.1 or 10 PC / laptop via your local network or a USB key. All my programs on this website have been produced using Delphi Pascal so never need actually installing - you simply copy the single EXE file to as many computers you have at home, in the office, branches, on-site as required and use it for your projects, all for nothing, for as long as you want with all updates / upgrades also free. If you decide you do not want to continue with FREEHCP, just delete it and it will be gone!

Using a CAD program to produce a drawing for FREEHCP :-

You prepare your isometric layout in your chosen CAD program as normal, drawing the pipes as LINE entities and the pipe sizes x lengths (as described later) as TEXT entities :-


You can use any units of measurement that you want but all the lines and text must be on the same layer number or name. Just ensure you give this layer name as the reply to Question 31 in the FREEHCP Job Data. All other entities on any other layers will be completely ignored. You only need to draw the pipes to the remotest design area, one by one, in any order you choose at any angles you prefer - you do not need to make these multiples of 30 degrees (30, 60, 120, 150 etc) but can lay them out as required to suit the paper / screen size. The only times that pipes need to be a specific direction is the convention that going at 0 deg (North) is vertically upwards and 180 deg (South) is vertically downwards in height / elevation. You do NOT have to draw out ALL the pipes in the system, just those from the source out to the operating sprinkler heads, so perhaps only 20-100 pipes to the 10-30 heads need to be hydraulically calculated, not the 300-1000 pipes / heads on the project!

All pipes are to be drawn on this layer as LINE entities (not 3Dlines or polylines) in any colour, width etc from the appropriate start X and Y co-ordinates nearest the source out to the end X and Y co-ordinates, where the sprinkler head/nozzle may be. The program therefore uses these start and end points to join the pipes together and work out where the heads are along with the routing to / from the source. Such lines / pipes will therefore not be to any scale so it doesn't matter what length you draw them - one a few inches on the screen could represent a pipe actually 1 ft or 100 ft long in the network.

LIBRECAD showing DEMO1.DXF zoomed in

Each section of pipe so drawn also needs a pipe sizexlength+options note (as described below) to be given as a TEXT entity (on the named layer but any height, orientation, colour, font etc) where the insertion point is at or near the pipe centre point. You may prefer to make all the text run left to right horizontally or at 90 degrees to the pipe rather than parallel to the pipe as there may not be enough room as shown on the "zoomed in" drawing above. This text must start with a number 1 to 8 being the nominal size in inches, all other text will be ignored.

All other LINES and TEXT entities drawn on any other layers will be ignored (so you can show pumps, tanks, heads, valves, elevations, title blocks, notes, descriptions etc to make the drawing readable and presentable) as well as any TEXT starting with A-Z and a-z. You also do NOT need to draw out any triangles, circles or other symbols representing the sprinkler heads / nozzles - you can (on other layers) if you want to make the drawing look nicer, but they will just be ignored by FREEHCP.

As you have been using CAD for many years now, I suspect it only take a few minutes to draw the lines, one by one, making up your system, copying / mirroring mains and branch-lines and not much longer to type in and position the 'sizexlength+options' text as described below.

When complete, SAVE the drawing in the normal format but my program needs a text-based DXF file so also remember to SAVE AS this (AutoCAD 11 / 12 or later text - not binary - type) as this also gives you a backup which may come in handy. Then run FREEHCP, and select "OPEN CAD .DXF file" from the "File options ..." menu and give this file name / location when requested. If you have not entered any project data in the matching .TXT file, then the program will prompt for up to 40 questions to be answered - most can be ignored but there are some key design parameters that need the appropriate data. Click on "OK" and you will then see that same drawing on screen with all the flow, pressure, velocity etc hydraulic calculations and Total Demand shown. Note that only the first two options are shown under "Edit ..." as if you try and now use FREEHCP to amend the drawing, it has no way of changing your original CAD scheme.

The main point to remember is that pipes have to drawn as LINE entities between heads and other cross- and feed-mains, exactly as you do for traditional hydraulics programs, as each has a specific flow rate, friction loss, velocity etc. You cannot just draw one line as a main and connect the branch lines along it - they have to be individual pipes (lines) between the heads and branch lines, each with one sizexlength text item. If you subsequently want to amend the drawing, you MUST do this in your CAD program (not FREEHCP) as you would not want the two to get out-of-step.

Using FREEHCP to produce a CAD drawing :-

Here, you can just use FREEHCP as a really simple CAD program to actually draw out the pipes / heads in the remotest design area of your project without having or getting involved with proprietary Computer Aided Design software, even though LIBRACAD is completely free. This is the way most people would wish to use my new program as it prompts / checks / logs all the changes to the layout and, at the end, creates a DXF file for reading into your selected CAD program if required. To assist, I have provided 4 demonstration examples, which you can "play" with, sorry, carry out a thorough technical evaluation, without typing in anything!

FREEHCP - DEMO 1 pipe 12

Every time you make a change to the pipes, a .DXF file is automatically produced (as well as .BAK, .LOG and .TXT formats). All can be viewed or changed with NOTEPAD or similar - not binary or hidden formats used by other suppliers to lock you into continuing with their expensive software.

Just either select one of my 4 examples, or "Open JOB DATA file" from the "File options" menu to begin. If starting anew, just type in an appropriate file name for your job (eg. MyJob1234) and, if it doesn't exist, a prompt will be given and the Job Data questions Q1 to 40 will be shown. Most can be ignored but there are some key design parameters where we need the appropriate data. Click on "OK" there and you will see 1 pipe just to get you started - you can now Add, Break, Copy, Delete, Edit, Move etc. as described under the "Edit ..." menu (below) to draw out your project, pipe by pipe, to one or more operating sprinkler heads as required. This, you will find, is very quick, intuitive and easy-to-use and creates a useful DXF file of the complete scheme for reading in / enhancing in any CAD program, if required.

Pipe data required for FREEHCP :-

This is the main feature and advantage of FREEHCP - only a small amount of information is actually required for each pipe section as we don't need node numbers or directions inherent in other hydraulics programs - you draw them out as an isometric so can always "see" what and where the pipes actually are. You just have the separate pipe sections going from the start position towards its end position across the screen (X co-ordinate) and up/down the screen (Y co-ordinate). All you do now is to indicate some essential data :-

Have a look at my demonstration examples or my results listings to see how little information is actually needed on a typical system - these are the ONLY items you need to type in, apart from the project data, of course.

The water supply / source will be at the start of the single pipe where nothing else connects to its start X / Y point as all the other pipes will have their start co-ordinates the same as one or more end X / Y points of the pipes that join it

The program will work out the actual pipe lengths as follows :-

The true pipe lengths will be this actual length plus the fittings (if any) equivalent length (depending on the nominal pipe size, fitting type, if S40 pipe type or not and if a different Hazen-Williams "C" factor different from 120) plus any value given under AE

Operation of FREEHCP, starting with File options ... :-

When you first start the program, there is only a "File options ..." menu visible. When you click on this, you will see these options :-

After OPENing or DEMO jobs, that scheme will be read in and the isometric shown on screen. Note the Total Demand values proving that the hydraulic calculations are complete with a 4 line help prompt in grey above the drawing inviting you to move your mouse cursor over the centre of any of the pipes. You can now see that the vertical up/down pipes are shown in a different colour (color) than the others and that the green text is all the text you actually have to type in, starting sizexlength as described above.


After you have moved your mouse over a few pipes to see all the input data and calculated flows, pressures, velocities etc. you can RIGHT-CLICK to zoom into the highlighted pipe to see the surrounding pipes at a greater scale (and then right-click again to zoom back to full size) and there are 3 more menus visible along the top.

FREEHCP - DEMO 1 zoomed in

Edit ...

Job data Q1-40 - When selected, a separate screen will be given being a simple spreadsheet of the 40 questions about the project and key design parameters with the first line highlighted. Just press the [TAB] key to move down the screen, or click your mouse over any reply (and again if you want to change some letters / numbers in that line) to make whatever amendments you want (and use the scroll bars to see Q24 to 40). Click on "OK" or "Cancel" as needed to remove the spreadsheet and return to the drawing, after which the hydraulic calculations will be repeated if you changed anything relevant.


Database - When selected, a separate screen will be given being a simple text editor of the pipe sizes, pipe types and fittings/valve types set of data I start you off with. You can also use NOTEPAD or similar if you prefer. Either click on "Cancel" or make some additions, revisions, deletions etc. to this and click on "OK" whereupon the new data will be saved (after making a .bak version) and the hydraulic calculations will be repeated if you changed anything relevant. Note that you don't have to use the one I supply but can copy, add to, delete, revise it as required to suit your company, projects or clients as may change over the years. You can also have several such files for different types of jobs / clients but all have to reside in the same folder / directory as the main program so that it can easily find them.

FREEHCP - Database

Add a new pipe - The drawing will be reshown at a slightly smaller scale (so you can extend beyond the previous boundary) with green and red blobs. You can add another pipe at any of the green blobs but the red ones mark places where there are operating heads which will get erased if you try and connect another pipe there because then you would have an invalid fitting!

FREEHCP - DEMO 1 start to add

As described in the grey text, choose where you want to add this new pipe, hold your mouse down at that node and then slide (drag) it in the direction / length desired (still holding the button down) until satisfactory and then release the button. As soon as you do, a little box will pop-up inviting you to accept or type in afresh the sizexlength+options text, and when done, press [ENTER] or click on "OK" or "Cancel" if not required. You can also hold your mouse over any of the box for hints or click on the grey text for a full screen of help. Note also that the 4 lines of text have changed at the top of the screen and you can slide the box in the usual way.

FREEHCP - DEMO 1 Adding a pipe

The hydraulic calculations will be repeated for the new pipework which may or may not be satisfactory and a line of text given at the bottom of the screen describing what you have done - in this case, you have too much pressure drop! The ADD and all subsequent options are only given if you have started from the job text file (not the .DXF one) so as not to get the CAD drawing out-of-step with the calculated layout.


Break a pipe - This will add a node blob in the centre of the selected pipe so that additional connections can be made. Again follow the 4 lines of grey help text to click on your chosen pipe and note that the mouse cursor has changed shape. Once you click on a pipe, the bottom line will show what has taken place and that the Total Demand values didn't change of course. You will now be back at "Edit ..." so can select Add, Break again, or Edit, Move etc.

FREEHCP - DEMO 1 break

Copy pipe(s) - Again the 4 lines of grey text at the top of the screen tell you what to do so click on the FIRST pipe (nearest the source) of the one or more pipes you want to copy to another place. As soon as you do (or press [ESC] if you don't want to), that group of pipes will be drawn in green and the cursor will again change shape and the 4 grey lines now invite you to click at the node where they are to be duplicated.


As soon as you click on a valid node, the hydraulic calculations will be repeated for the new pipework which may or may not be satisfactory and a line of text given at the bottom of the screen describing what you have done. You will now be back at "Edit ...".

FREEHCP - DEMO 1 all copied

Delete pipe(s) - The 4 top grey lines will describe the simple operation of clicking on the FIRST pipe (nearest the source) of the one or more pipes you want to remove. As soon as you do (or press [ESC] if you don't), that group of pipes will be drawn in red and a warning message given asking you to click on "Yes" to delete those pipes or "No" to leave them as they are. If you click on "Yes", the hydraulic calculations will be repeated for the new arrangement and a line of text given at the bottom of the screen describing what has happened. You will now be back at "Edit ..." again.

FREEHCP - DEMO 1 deleted

Edit pipe data - The 4 top grey lines will describe the procedure so just click at or near the centre of the pipe you want to change (it gets highlighted in the normal way) and a little box (same as in ADD) pops up so you can accept or type in afresh the sizexlength+options text, and when done, press [ENTER] or click on "OK" or "Cancel" if not required. I take it you will know now that the hydraulic calculations will be automatically done to show the changes if any to the Total Demand values and so you can continue to click on pipes to view / edit their data until you press [ESC] or select another Edit option.


There is a full "help" page which describes all the information about the edit options :-

FREEHCP - DEMO 1 edit help

Move nodes - Again, the drawing "jumps" in a bit so you can move the pipe ends beyond the current boundary and you are prompted as what to do next so just hold your mouse button down when over the required junction or head and then slide it in the desired direction / length until satisfactory and then release the left hand button. The calculations have to be repeated just in case you made one or more of the pipes vertically up or down the screen (so changing the height / elevation) and you can continue to hold the button down, sliding then releasing it on any other nodes you want until you press [ESC] to cancel. As you drag the mouse around with one or more pipe ends in tow, you will find that you cannot join them up to any existing pipes - this is deliberate to stop you accidently looping the pipes and then not being able to break them apart. I have obviously exaggerated my "move" on the drawing below so can you tell which one I changed?


Spreadsheet - As some of you may already be familiar with this method of data entry / amendment, I have arranged for the pipe data, along with the start X / Y and end X / Y co-ordinates to be presented in this format. You can make whatever changes you desire before selecting "OK" or "Cancel". There is a nice option to highlight the text containing specific codewords - just choose the appropriate one in the bottom left hand corner and, for all matches found, those lines will be shown in blue.

FREEHCP - DEMO 1 spreadsheet FREEHCP - DEMO 1 job data

Save as JPG - this just takes a copy of the current screen as a .JPG graphics file of the name shown on the pop-up message, which is just the current time. This file can be printed out, amended, changed to another format or sent to other members of the design team as required.

Undo last edit - Each time you make a change to the data and repeat the calculations you increase a 'step' number from 1 to 99 which is shown in grey along the bottom of the screen. Should you decide that a certain change was not required or caused problems, then select this option to go back, one step at a time, to the initial reading in / calculation. It works in sequence with "ReDo".

Redo last undo - Just does the opposite of the previous "UnDo" option, that is once you have gone back one or more steps, you can proceed forward again to the next edit / calculation. I hope you may find these of use in the creation / amending of your project, but if not of interest, they can be ignored as you can just delete any added or copied pipes or retype any edited text in the normal way.

The best way to investigate these last two options is to try all the various EDIT options on one of my DEMONSTRATION JOBS such as adding, breaking, copying etc. to get familiar with this important aspect of FREEHCP and then, just for fun, go backwards and forwards reviewing those changes - it doesn't matter what you do as the set of data is reset every time you load one of these examples.

Display ...

Summary - This just shows a series of minimum / maximum values of various design parameters that might be of interest or which can be ignored if not needed. Click on "OK" to return to the drawing.

FREEHCP - DEMO 1 summary

Graph - The water supply graph as required by the NFPA Rules is displayed showing how the psi and gpm safety margins have been worked out on a 1.85th power law of flow. It has been saved to the .JPG graphics file indicated to attach to the results presentation if needed. Just click on "Redraw" or press [ESC] to return to the top of this menu. Please refer to the 'Special AHJ data files' description below for how this program can create a special text file for Emailing to your AHJ rather than having to use PDF files, which some may now reject. I hope you, and your AHJ, like to see the graph full-screen in colour (or color) as against a black-on-white-is-all-you-get from other software suppliers.

FREEHCP - DEMO 1 graph

Results - This option will show the first page (of as many lines as can be fitted on your screen) of the multi-page results listing as required by the NFPA Rules. You can press the "Home", "End", "PgUp", "PgDn", "up" or "down" arrow keys, rotate your mouse wheel or just click on the top or bottom half of the screen to go up or down the other pages until you get to the last line confirming that this program, and any updates / upgrades, are completely free. Lines highlighted in red or purple will draw your attention to high velocities, heads under or over pressure etc. Note that I use a modern, fixed-space font so that all the columns and decimal points are lined up, in colour, to impress your AHJ and make it easy for them to accept your calculations, especially as you can give them a FREE copy of FREEHCP so that they can "see" all the pipes visually full-size on screen, without having to track down where on earth pipe 200 - 210 is on a huge CAD drawing! Just click on "Redraw" or press [ESC] to return to the top of this menu when all taken in.

FREEHCP - DEMO 1 results 1 FREEHCP - DEMO 1 results 2

Print - will simply redraw the results (if not already shown) with a "Printer SetUp" box inviting you to select which printer (or PDF printer driver or Microsoft XPS Document Writer if no printer is installed on your computer) you want to use, then click on "OK" (or "Cancel" if not required) when the results listing will be printed out and a little message given at the end telling you what has happened. You can double click on the file name given in your "Documents" folder if the XPS option was selected to see it on the screen. Please refer to the 'Special AHJ data files' description below for how this program can create a special text file for Emailing to your AHJ rather than having to use PDF files, which some may now reject.

FREEHCP - DEMO 1 print

Pipe data

This just permits you to see different items, such as sizes, lengths, K-factors, flows, pressures etc as green text on the drawing in place of the pipe number / data seen before. Once highlighted, you can press the "up" or "down" arrow keys to cycle through the extensive list. It will be changed back to pipe number or pipe data in the various "Edit" options.

FREEHCP - DEMO 1 pipe sizes

Special AHJ data files

FREEHCP automatically saves the text and .DXF files as you change them during a session as well as a special +2AHJ text file. This contains all the Q1 - 40 replies, the X / Y positions and data for all the pipes and the pipe / fittings database. This has all the data necessary to calculate the hydraulics and is intended for Emailing to your Authority Having Jurisdiction. They can also download FREEHCP for FREE on their PCs and will therefore see all your drawing and will get the same hydraulic calculations results, graph and interactions with the interactive nature of the system.

So after you have looked at one or more of my Demonstration examples, may I suggest you imagine yourself as a AHJ and use the "Open JOB DATA file" from "File options ..." to read in the FreehcpDemo1+2AHJ file into FREEHCP and see what you can and can't do with it, as well as to look at it in NOTEPAD or similar. You may also want to see if the .LOG information is of interest in any regulatory compliance activity.

Well, the AHJs can also look at the +2AHJ file in NOTEPAD or similar but will not be advised to amend it - I did think of making it 'read only' but anybody who has used 'Windows' for a couple of weeks knows how to reset such a marker, so there was no point!

Before using FREEHCP on your actual projects :-

If the following screen shots from my other demonstration examples are not as clear as you would prefer, it will be as quick to download the program and run through them yourself, full size on your monitor and spend a useful 10 minutes evaluating my latest program. You can also view the demo DXF drawings in your existing CAD program, remembering to zoom-in, zoom-all, zoom-extents or zoom-auto to see the whole scheme. If not suitable for you, your company or your projects, just delete it and it will be gone as I do not ask for any registration, Email addresses, licence agreements, payment details or any personal information whatsoever - you remain anonymous.

I suggest you spend a few minutes looking at my STANDARDFREEHCPDATA pipe / fitting types data file in NOTEPAD or similar and adding to or amending the data to suit your company, projects or clients. Then print it out and keep it next to your PC as it contains a list of the codewords for reference.

The other 3 demonstration examples are :-

FREEHCP - DEMO 2 layout FREEHCP - DEMO 2 graph FREEHCP - DEMO 3 layout FREEHCP - DEMO 3 results FREEHCP - DEMO 4 layout

I will leave things here for now - if I have left anything out or not described the items in enough detail, then please Email me for a more comprehensive explanation of any problems encountered in following this website or entering / amending data for the program.

Thank you for reading about FREEHCP - I hope you can find the time to download and evaluate it and can easily apply it on all your future projects - Alan Ashfield September 2017