Free Hydraulics Calculations Program FREE1315 by Alan Ashfield


Introduction to FREE1315 - 25th May + 14 June 2018:-

FREE1315 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.

FREE1315 Demo 1 Flows on isometric

I am given to understand that I have inadvertently broken one guideline of the NFPA Rules with my previous FREEHCP program - that is by automatically allocating node numbers! To save you having to type these in on the drawing, I just started at a given number and sequenced them up or down as specified eg. start at 100 and then steps of 10. Apparently, you all prefer the NFPA 13 recommended descriptive noding scheme whereby the mains and branch line / head junctions had meaningful references like BOR, TOR, CM6T, FM2-4 or BL1#3 and not all numbers!

I have therefore produced a Mark 2 version of FREEHCP and called it FREE1315 and gone back to a more traditional software format whereby the user enters all the node references of the junctions of pipes and operating heads with one additional item of data, that is, the direction of run. This permits FREE1315 to show plans, elevations and isometric views of the network as well as automatically finding the elbow and tee positions. You just click on any of the 8 "pages" across the top part of the screen to view that particular option - that's all.

This, I think you will agree, is a vast improvement on the many established programs in this field which do not even think about generating a 'drawing' of the pipework arrangement relying on the user to hand draw the layout (and keep referring to it) during the data entry and understanding the results printout.

You can use a spreadsheet type grid arrangement of rows / columns to enter or amend the information for the pipes or you may prefer a full screen editor approach as well as clicking on pipes shown the various drawings to view, add or revise the pipe information, all as described below. Like FREEHCP, this program 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.

Full technical support is offered for free by Email (my address is on the top line) - please put FREE1315 in the "Subject" line (I do have 20 other FREE programs on my website!). Just scroll down this page for more detailed help and information on all its features and options.

You must already have read and understood the NFPA 13 "Installation of Sprinkler Systems" and / or NFPA 15 "Standard for Water Spray Fixed Systems for Fire Protection" (but NOT NFPA 13D, 13R or 14) as this program does NOT design the pipework system - you have to produce the sprinkler layout drawing before trying to do the hydraulic calculations with FREE1315.

Download FREE1315 from this HTTPS website :-

You can DOWNLOAD THE LATEST VERSION OF MY FREE1315 PROGRAM [14th June 2018 = 887 kB] now by clicking here and "Saving" it to a suitable folder on your hard disk, such as C:\AA3PROGS or C:\free1315 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 - you get one, small EXE file. When run for the first time, select "File options" and "NFPA13 Example" to see the display below ...

FREE1315 Demo 1 Flows on isometric

From this screen-shot, I suspect you already understand how to use this new program so I will just expand on the various options for the rest of this webpage. FREE1315 is essentially a simple, modern "point and click" user interface where you only have to click your mouse when the cursor is positioned over a specific part of the screen to carry out that operation and various options are usually in different colours to distinguish them from other sections.

File options

You can choose to enter a NEW sprinkler system (which starts at the 'Job data'), to OPEN an existing data file previously prepared and create a .BAK copy or SAVE AS to copy information into another file for alternative investigations or to keep backups in another place. I have also provided 4 DEMONSTRATION examples to show the program facilities for you to see what is involved in its operation. I have also transferred the HEADS IN A ROOM part from FREEHCP and you can also EXIT this application here and return to the "Windows" desktop. 14th June 2018 - To assist in the correct sizing of branch lines, I have added a FLOW V PRESSURE DROP GRAPH screen where you just select the pipe type, Hazen-Williams "C" factor and maximum flow in gpm to see :-

FREE1315 Q v P Graph

The main part of the screen is taken up with 8 PAGES / TABS of different options so just click on them as described next.

Job data

FREE1315 Demo 1 Job Data

This spreadsheet-like display allows you to enter or amend up to 40 questions about the titles, descriptions and design parameters of your project / design area and you just need to press the [TAB] key to move down the list. All information not related to the actual pipework is contained in this one place including your name / address.

Pipes spreadsheet

FREE1315 Demo 1 Pipes Spreadsheet

There are 4 items of data necessary for each pipe section, starting at the water supply source and out, through the feed and cross mains, to the individual branch lines holding the sprinkler heads / nozzles. Remember that you only need to include 10 to 50 (or more) operating heads in any design area, regardless of the number actually installed in the building or area ie. an ESFR system will always have just 12 heads operating.

  1. A START NODE reference (up to 8 characters such as BOR, ENDFM2, UGMAIN, BL1#4 etc) and if you type a-z characters and/or 0-9 numbers but no 'spaces', they will be converted to upper-case eg. bl3h4 will come out as BL3H4 on the results printout or a number (1-99999 if applicable eg. 560) at the beginning of each pipe nearest the source. This must have been given as END NODE of a previous pipe, either the one before or further back into the system at a tee / cross where you had a choice of going straight through or around a branch connection and will come back to the other outlet later - you seldom need to include 'through tees'. In other words, all pipes are assumed to be supplied by the immediately previous pipe unless you specify otherwise but giving the corresponding start node. So I have permitted you to type 0 as a start node and the program will "look up" the end node of the pipe before for you.
  2. An END NODE reference at the end of the pipe, sometimes where any operating head is, and may connect to the START node of another pipe further into the network eg. BOR or BL1#3 or 570. The pipe may also have a head at its start node but that would have been given as the end node of the previous (or immediately upstream) pipe. Loops are formed when two end nodes are the same and match up with similar X, Y and Z co-ordinates (as FREE1315 is generating a 3D picture of your system) so making it really easy to create looped, gridded, birdcage and ring-main type layouts. You cannot have any heads at this junction and will get warning messages if you accidentally specify two equivalent end nodes on different pipes. The end node cannot be the same as the start node (as the pipe wouldn't go anywhere) nor the same as the start node at the source as the system would then feed itself!
  3. A DIRECTION of run from the start to end as a compass point (N, NE, E, SE, S, SW, W, NW or U for vertically up or D for downwards) or an angle from North in the range of 0 to 359 eg. 180 = south. North is always from bottom to top on the screen in plan view. This also allows the program to automatically find the 'elbow' and 'tee' positions so, in most cases, you only need to indicate where any alarm / control valves are located.
  4. The actual data for the pipe starting with SIZE in inches x LENGTH in feet (eg. 1.25x10 or 3x45 or 1x11.06 for 11'6") and then one or more optional items like = for pipe type (eg. =CM), + fitting (eg. +GV or +2E or +0 to 'rub out' any incorrect fittings along the back tracks of gridded systems), pc for a different Hazen-Williams C factor (eg. pc110), ps for pipe slope in degrees if not horizontal / vertical (eg. ps6 or ps-12.5), ak for an added orifice plate K factor (eg. ak56), ae for an added equivalent length in feet (eg. ae34), ap for an added pressure drop in psi for any special devices / equipment (eg. ap4), af for an added constant flow in gpm for hydrants, hosereels etc (eg. af250), uh or ph for upright or pendent sprinkler heads, hm for a different head minimum pressure in psi to the standard (eg. hm15), hk for a different head K factor than the majority (eg. hk9), hc for a different head area of coverage in sq.ft that given before (eg. hc120) or hd for a different head density in gpm/sq.ft (eg. hd0.2). So you could have data like 1.25x6, 1x12uh, 3x3=CMpc100 or 6x20=S10+AVap4.5af100. Although you may think this is quite involved, please remember that some are seldom used and the right hand side screen shows the full extent of these options as a prompt and you will soon get used to the common ones.

Node references / numbers are therefore required at the source, where the pipe sizes, types, directions or slopes change, before and after control valves, at junctions of elbows, tees or crosses and at operating sprinkler heads / nozzles. So if a pipe runs around a column or obstruction, then that may entail 4 separate pipe sections rather than just one in older hydraulics programs that can't show such an 'offset'. The best approach is to start at the source and work outwards, along the only or any route you choose, through the cross and feed mains to the 3 or more end- or centre-fed branch lines supporting the operating heads / nozzles in any convenient order. You then finish by giving any extra pipes to 'loop' or 'grid' the system. Do NOT type in all the pipes at one session and then see what the calculations and drawing look like but click on that option (or press ALT-C together) every 5 or 10 or so pipes, so if you do get any warning messages, it will be easier to find your typing errors! You do not need to start or end the pipe data at the most remotest head / nozzle as the program will automatically find it and make it blue on the drawing. You can go backwards from the remotest branch line / head towards the water supply if you want but will find this more difficult and prone to error as you must insert pipes at the beginning of the list rather than always adding new pipes on at the current end.

A complete pipe description could look like BL1#4 BL1#5 N 1.25x12uh or CM5-2 CM5-3 E 3x12 or BL4BT BL5BT 180 4x11.06+0 so please view my 4 demonstration examples to see how this system works on real jobs.

Like any spreadsheet you may have previously used, you move the highlighted row / column 'cell' around with the 'arrow' keys or mouse to add, amend, insert or delete more pipes as needed pressing [TAB] to register such changes. The bottom line of the screen always shows the current row / column cell and a 'hint' confirms the general reminder. Alongside the grid is a full "help" information screen describing all the various options and features so just use the 'scroll bar' to view the rest of these extensive hints in grey.

Pipes editor

FREE1315 Demo 1 Pipes Editor

This is my NOTEPAD lookalike whereby all the data for the pipes is shown, one per line, and you can move the | cursor around with the 'arrow' keys or the mouse to add more pipes anywhere in the list or revise the numbers / letters in the same 4 columns of information as just described. All the data needed to describe the example job in the NFPA 13 Rules is shown in blue on the left hand side - compare that with your current hydraulics program and check you get the same answer as FREE1315.

You don't have to line up the information to save time - just so long as there is at least one 'space' between the items is all that is needed. The bottom line on the screen always confirms the line of original data before you press [ENTER] to add another pipe at the current end or inserted anywhere in the list. The same "help" screen is given right where you need it - next to the data entry / amendment screen so no more 80 (or even 147) page user manuals to download / wade through, or buy! You can choose whichever format, GRID or EDITOR you are more happy with and can therefore easily swap between them as necessary. If preferred, you can also use a separate editor (like NOTEPAD) to enter or amend the whole job data.


FREE1315 Demo 1 DataBase

The program starts you off with a set of pipe size, pipe and fitting type information that you can retain, delete, add to or revise to suit your own projects / clients / offices requirements and you can have several of these as separate data files as needed. Again, this is presented as a full screen editor where you can make whatever changes are necessary and you can additionally print it out for reference next to the monitor.

Calculations and Drawing

FREE1315 Demo 1 Calculations

As the previous 4 pages / screens allow you to make whatever additions and / or changes required to your project, FREE1315 cannot do the hydraulic calculations and show the drawing there because

Therefore you need to select this page when ready to automatically save the data, recheck it, carry out all the balancing of the flows and pressures in the pipes to the heads and display the required drawing, with or without the pipe data or calculated results labels next to the pipes. Don't worry, this only takes a fraction of a second even for complicated gridded systems so the screen will update as soon as you take your finger off the mouse button.

You can choose a PLAN, 4 ELEVATIONS from the 4 edges of the screen, (remember North is at the top of the screen in plan view), 4 ISOMETRICS from the 4 corners of the screen or a JPG graphics file of the current display. You can use the 'scroll bar' underneath to slide the 'blob' left or right to adjust the isometric angle from 1 to 60 degrees (as the standard is 30) which may resolve any overlapping pipes / labels at different heights.

You can also show one of over 25 LABELS in green next to the pipes / heads, such as node number / reference, size, lengths, pipe types, K factors, flows, pressures, velocities, densities etc. Pipes are usually shown in blue but will be drawn in different colours (colors!) to indicate excessive velocities, wrong pipe sizes, pipes without a flow through them (perhaps missing heads), duplicate nodes etc. Don't forget that I supply 4 demonstration jobs that you can look at without entering any data whatsoever to try out all these options.

Also, while you have this screen showing, you can EDIT the data on any pipe just by clicking the left mouse button at or near the pipe centre. Or you can ADD another pipe at any junction (not at intermediate heads) just by left-clicking near the corresponding end node. In both cases, the hydraulic calculations / redrawing is carried out immediately after you change the pipe data.

FREE1315 Demo 1 Isometric showing sizes

As your system may be quite extensive or you have a small screen, you can ZOOM IN to any pipe by right-clicking its centre (in plan or isometric views not an elevation) and can then select any edit or add points easier. To return to the previous full size plan or isometric, just right-click again anywhere on the drawing to ZOOM OUT again. Note that the top and bottom lines of the drawing may give useful / essential warning notes.

FREE1315 Demo 1 Zoomed in pressures


FREE1315 Demo 1 Results

When selected (not necessarily after the "Calculations and Drawing" page), this will show the first page of the results presentation being my version of the NFPA 13 / 15 'handwritten' format. You can press the 'PgUp', 'PgDn', 'Home', 'End', up or down 'arrow' keys, rotate the mouse wheel up or down, or click on the top or bottom half of the screen to move up or down one "screen-full" at a time to see the rest of the accurately balanced calculations to two decimal places of flows in gpm and three decimal places of pressures in psi (just like the other software you may now have or previously used). To get a printout, either to an attached or networked / wireless inkjet or laser printer or directly to a PDF file (with a free PDF printer driver) just click on the PRINT button which has appeared on the top line of the screen. If you right-click on the results, a "calculations summary" will pop up so just click on OK to cancel it.


FREE1315 Demo 1 Graph

This will show the total demand and system design lines and safety margin on a 1.85 power flow / pressure graph. A JPG graphics file will be generated automatically and the file name used is confirmed on the bottom of the screen. If you haven't worked it out yet, you just need to click on another of the 8 'pages' to view that data / information ...


This only shows this webpage on the screen to complement the various help displays inherent in FREE1315 to assist in your understanding of it and hydraulic calculations in general or to view my other 20 free programs that may or may not be of interest.

FREE1315 program

All my 21 free software applictions will work on "Windows" XP, VISTA, 7, 8.1 or 10 operating systems with a minimum 1366 x 768 pixel screen on any 11-15" laptop, a 22-32" HD display on any desktop or all-in-one PC or a 4K monitor on a CAD workstation. All are completely FREE and there are no charges from me or anybody else whatsoever now or at any time in the future, without activation, registration, Email addresses, licences, dongles, copy-protection, subscriptions, donations, user tracking or anything else!

Demonstration Examples 2 to 4

FREE1315 Demo 2 Node numbers FREE1315 Demo 3 K factors FREE1315 Demo 4 No text on isometric

Thank you for reading about FREE1315 - I hope you can find the time to download and evaluate it and will be able to use my latest program on all your future projects - Alan Ashfield May 2018