Know whether your pipe
holds.
A pipe that heats up wants to expand. FlexPIPE calculates what that does, and whether it stays within the code. A proven calculation core from the oil and gas industry, as a program on your own laptop.
FlexPIPE 2026.1July 2026Ask what changed
- One-time licence
- No subscription
- macOS and Windows
- Anchor
- Guide
- Loop
- fixed
Where it stands
Every installation stands somewhere.
In a valley, at a forest edge, in the wind. Temperature and surroundings are part of the sum, not just the pipe itself.
The clearing
The ground first.
A foundation, two plinths, the vessels. Everything that follows leans on this, and everything that expands pushes against it.
The pipe
Then the steel.
Pipe, bends, clamps. Every node is a place where forces meet, and that is exactly what FlexPIPE calculates.
And then the heat
The steel wants to grow.
The heat travels through the pipe and it expands. The only question is: how much, and will it hold?
Calculates to
Built and maintained by Damian de Raad, mechanical engineering TU Delft.
What you use it for
A pipe that heats up wants to expand.
If it is restrained, stresses build up — in the pipe itself, in the bends, and in the nozzles of the equipment it connects to. FlexPIPE analyses that system and shows you where you run into the allowable stress. Before any steel is laid.
- From input to report
- Enter the system, assign loads, calculate, and get a report that goes straight into the project file. All in one program.
- Runs where you run
- macOS and Windows, from the same project. No prerequisites to install, no administrator rights needed.
- Keeps working
- One licence per workstation, without a subscription and without a server that could ever go dark.
- Anchor
- Guide
- Loop
- fixed
Cold
Everything is still, everything fits.
At ambient temperature the pipe meets its flanges neatly. No force yet, no moment.
Heating up
Steel gets longer.
A metre of steel grows about one millimetre per hundred degrees. Over a fifty-metre run that is five centimetres that have to go somewhere.
The loop
The loop takes it up — and the anchors feel it.
The loop flexes and keeps the stress low. FlexPIPE calculates, node by node, how much remains and whether it stays within ASME B31.
Origins
No new calculation engine.
That is the point.
In stress analysis, new software is a risk. Nobody wants to be the first to discover an error in the calculation.
FlexPIPE was originally written by G.A.P. Heidema and used for years at engineering firms and contractors. The calculation method has been kept; the program around it was rebuilt by Damian de Raad, mechanical engineer (TU Delft).
Reference projects of the original software
These companies used the original software. Listing them is not an endorsement and not a current customer relationship.
Almost there
Hear first
when it is here?
FlexPIPE is almost ready to ship. Leave who you are and what you want to use it for; you will be the first to hear, and you can then try it on your own files before you buy anything.
You leave your situation
Number of seats, operating system, and what you use it for.
One message
As soon as FlexPIPE is available. Nothing else.
Then: test it yourself
A temporary licence to run one of your own projects, followed by a concrete proposal.
Frequently asked questions
Before you buy
Which codes does FlexPIPE calculate to?
ASME B31.1 (power piping), B31.3 (process piping) and B31.8 (gas transmission piping). The calculation methodology comes from the original software used for years in the oil and gas industry.
Can I test it on my own files first?
Once FlexPIPE is available, yes: with a temporary licence you run one of your own projects and compare the results with what you are used to. Leave your details and you will be the first to hear.
We already use Caesar II. Does FlexPIPE still make sense?
It can be. Caesar II is the standard. FlexPIPE is useful when you want a second opinion, when licence costs are a concern, or when you already work with .FLX files.
How should I assess the results?
Run a project whose result you already know. That is the only test that counts. Always verify results yourself and follow the codes and procedures that apply in your situation.
What does it cost, and is there a subscription?
It will be a one-time amount per seat — no subscription, no annual renewal, no maintenance contract. The exact amount follows once FlexPIPE is available.
What happens if the licence server ever goes down?
There isn't one. The licence key is verified locally, so there is no activation server that can go down. The software keeps working.
Questions about the calculation itself?
I answer those myself. I built the software and studied the field; you are not talking to a sales department.