How Pihasa Assistant Calculates

Every support datasheet you complete produces a result: a selected model, a set of positions, a take-out list and a weight. This article explains what happens between the data you enter and that result, so you can read any output with a clear idea of where each number came from.

What the software does and does not do

Pihasa Assistant is a selection and verification tool, not a stress analysis program. The distinction matters.

It does:

• Select a catalogue model that satisfies your load and movement requirements
• Position that model within its travel range
• Check the result against a set of admissibility criteria
• Size the assembly — rods, take-outs, clamp dimensions
• Estimate weights and produce the bill of materials
• Generate the drawings, datasheets and reports

It does not:

• Calculate the loads acting on the support. You supply them.
• Calculate the thermal movements of the pipe. You supply them.
• Perform stress analysis of any component. It verifies that loads stay within tabulated allowables; it does not compute stresses.
• Combine load cases. Each check is evaluated independently, with no simultaneity factors.

Type of support, loads and movements come from your pipe stress analysis. Pihasa Assistant takes them as given.

The five stages

Whatever the support type, the sequence is the same.

1. Preparing the calculation load

The Load you enter is not necessarily the load used to select the model. Before selection, the software may adjust it:

• Converted to kilograms if the project works in newtons
• Halved, if the support is double and Load Calculations is set per support
• Increased by the weight of the accessories, if the project is set to include them
• Converted into a nominal load considering temperature and material quality, where the component’s capacity depends on both

Which of these apply depends on the support type and the project settings. The support datasheet shows the resulting calculation load.

2. Filtering the catalogue

The software queries the catalogue for every model whose working range covers the calculation load and whose travel range covers the required movement. This is a filter, not a choice: it returns all candidates.

3. Positioning

For spring supports, the selected model has to sit somewhere within its travel range. The software determines the hot position from the load, and the cold position from the hot position and the vertical movement.

4. Checking

Each candidate is then tested against the applicable criteria: travel limits, travel reserves, variability, hydrostatic load, material quality against temperature, and so on. Candidates that fail are discarded.

5. Choosing

From the surviving candidates, the software proposes one.

This last step deserves attention. If no candidate passes every check, the software still proposes a model — the best available from the filtered list, without the restrictions applied. It does not refuse to answer.

That means an automatic proposal is not a validation. It is a starting point. The warnings shown on the datasheet tell you whether the proposal actually satisfies the criteria, and it is your job to read them.

Where the data comes from

Three sources feed every calculation:

The first is yours to control. The second is updated when the Pihasa catalogue changes. The third is the engineering criteria embedded in the product, and is the reason two engineers entering the same data get the same support.

Rounding

The software rounds up to the next multiple, not to the nearest value. A dimension that lands on 322 mm becomes 325 mm; one that lands exactly on 325 mm stays there. The multiple depends on what is being rounded — travels, assembly dimensions and design loads each have their own.

The practical consequence: results are conservative by construction, and a value you calculate by hand may sit slightly below the one the software reports.