Hi, I’m Long.
I build RiserSheet. Here is what it does, what I decided it would never do, how the arithmetic is checked, and how to reach me.
I write RiserSheet on my own, in upstate New York, under Crux Labs. One person, not a company pretending to be one.
You enter a water supply, a sprinkler network as a spreadsheet of pipes and nodes, and a design criterion. RiserSheet solves the network in the browser on every keystroke, shows pass or fail against your supply curve, and produces an NFPA 13 formatted PDF for the plan reviewer. There is no Calculate button anywhere in it, because a calculation that only runs when you ask it to is a calculation you can forget to re-run.
It does the calculation half of a CAD-based sprinkler package and none of the drawing half. That is a decision, not a gap I intend to close. The six calculators run the same WebAssembly solver the paid app runs, so the answer on those pages is the answer inside the product, and the product tour shows every screen before you sign up for anything.
I answer my own support email. If something is broken or missing, tell me and it goes on the list that day. If a number looks wrong, that is not a support ticket — that is the most important message this address can receive, and it gets a fixture written for it.
RiserSheet is a long-term project. I am not flipping it and not chasing a round, and I am not going to bolt on drawing, estimating or project management. The job is to make the calculation half correct, fast and cheap enough that a one-person shop can afford it, and to keep it that way.
What I decided it would not do
Stated plainly, because the most expensive wrong answer about this product is one that says it does these.
- No CAD and no DXF import. The Design view draws the network you calculated; it is not the drawing you submit.
- No sprinkler placement or spacing rules. The designer decides where heads go.
- No pipe schedule method. Hydraulic calculation only.
- No native apps. Web only.
- The designer of record is responsible for the inputs, the code edition and field verification. The software performs the arithmetic.
The full list of limitations sets out the rest: where a reference table is still being checked, where the standard prints a curve rather than a number, and every other place the judgment is yours rather than the software’s.
How I check the arithmetic
I do not ask you to take my word for it. 29 networks are derived independently — by hand on the simple ones, by a separate implementation on the loops and the standpipe — then re-solved and compared value by value. That is 345 quantities checked, of which 260 come back bit for bit identical. The solver is one Rust crate compiled both to WebAssembly for the browser and natively for the server, so the number you read on screen and the number in the PDF are produced by the same code.
The validation page publishes the whole comparison, including three complete calculation reports printed by incumbent hydraulic packages that were transcribed and re-solved, the differences that remain, and what is still outstanding. I wrote it to be read by somebody looking for a reason not to trust this.
Who is responsible for the calculation
You are. RiserSheet performs the arithmetic and shows its work. The designer of record stays responsible for the inputs, for the code edition the authority having jurisdiction has adopted, and for field verification. Every report carries that statement, and a result that passes is not an approval. The terms of service set out the same position in full. I am not your engineer of record and support is not plan review.
Common questions
- Who makes RiserSheet?
- Long Nguyen, a solo developer in upstate New York, under Crux Labs. One person, not a company pretending to be one. I answer my own support email.
- Is this going to still be here next year?
- RiserSheet is a long-term project. I am not flipping it and not chasing a round. Every report you generate is a PDF you keep, and it stays readable whatever happens to me.
- Does RiserSheet draw the sprinkler system?
- No. There is no CAD and no DXF import. The Design view draws the network you calculated from the sheet you typed; it is not the drawing you submit. RiserSheet does the calculation half of a CAD-based sprinkler package, not the drawing half.
- What does it cost?
- The six calculators are free and need no account and no email. The full app is a subscription per designer seat, monthly or annually, with a 14-day trial that needs no card and includes every feature. A single report can be bought once for one remote area without a subscription. Reviewer seats are read only and free.
- Which edition of NFPA 13 does it use?
- Reference data is for NFPA 13 2022, and every record carries the edition and the table it was transcribed from. You choose the edition and the local amendments your project is held to. The software does not decide that and does not check it.
- What do I do if a number looks wrong?
- Send me the inputs that produced it at [email protected]. A reproducible disagreement becomes a golden fixture, which means it gets fixed and then stays fixed.
Say hi
Write to [email protected]. It comes to me. If you have found a number you believe is wrong, send the inputs that produced it.
Know the margin.
The trial runs 14 days with every feature and no card. You land in the finished sample project, so the first calculation you read is a completed one.