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Parameter Help
Hover any parameter to see what it means, the equation behind it, the typical design range, and the standard it comes from
Introduction
Design forms ask for a lot of numbers, and the number on its own rarely says what it is for. Every parameter in ErgoPlanner that has an engineering definition carries a small help icon beside its label. Open it and you get the same six things every time:
| Shown | What it tells you |
|---|---|
| Name and symbol | The full parameter name and the conventional symbol (SLR, HRT, Q) |
| Unit | The unit the field expects, in square brackets |
| Description | One or two sentences on what the parameter is and why it matters |
| Equation | The governing equation, typeset properly |
| Typical range | The design range, and a representative value where one exists |
| Reference | The published standard or textbook the figure comes from |
Where you will find it
Process calculation forms
Every input on the flow-and-load build-up and the process unit forms:
- Flow and load — population, per-capita consumption, growth, infiltration, trade effluent, per-capita loadings, consents, storm tanks, and the derived flows (DWF, 3 DWF, 6 DWF, Formula A, FFT)
- Primary tanks — geometry, surface loading rate, retention, removal efficiencies
- Biofilters — media geometry, specific surface area, volumetric loadings, wetting rates, recirculation
- Humus tanks — geometry, hydraulic loading rates at each flow condition, the N-1 case
- Chemical dosing — chemical properties, target phosphorus, metal:P molar ratio
- Alkalinity — the full balance from influent alkalinity through to the supplement required
- Sludge — mass flows, dry solids, liquor returns, storage
The Draw properties panel
Element properties on the canvas — flow, pressure, diameter, pipe size, velocity, material, pressure rating, head, power, tag number and the rest — carry the same help where the parameter is one ErgoPlanner recognises.
Properties that are specific to your own symbol library or property template show as a plain label with no help icon. That is deliberate: a help icon that opens an empty panel is worse than no icon at all.
Using it with the keyboard
The help icon is a real button, so it is reachable without a mouse:
- Tab to the help icon beside the field label.
- The tooltip opens on focus — no click needed.
- Tab again to move on; the tooltip closes behind you.
Screen readers announce the tooltip as the description of the button (aria-describedby), and each button is named after its parameter — for example "About Design Surface Loading Rate".
Reading the equation
Equations are typeset with KaTeX, so a fraction reads as a fraction and subscripts sit where they belong:
$$ SLR = \frac{Q}{A_s} $$
If the equation cannot be typeset — an old browser, a blocked asset — it falls back to a readable single-line form (SLR = (Q)/(A_s)) rather than showing raw LaTeX or an empty box.
Reading the range
The range is the typical design range, not a validation rule. Nothing stops you entering a value outside it; the form's own compliance checks are what decide whether a design passes. Treat a value outside the range as a prompt to justify it, not an error.
Where a representative figure exists it is called out separately:
Typical range 24 – 40 m³/m²/d
Typical: 32 m³/m²/dReading the reference
References cite published standards and textbooks — BS EN parts, ATV-DVWK-A 131, Metcalf & Eddy, WEF MOP 8, the relevant Directive — so you can trace a design figure to its source in a design statement or a technical query.
Where a project follows a client's own design standards, those take precedence over the figures shown here. The tooltip tells you what the published literature says; it does not know your project's specification.
When a parameter has no help
Not every field is an engineering parameter. Scenario names, descriptions, data sources, assumptions and audit fields such as "last updated" carry no help icon because there is no equation, range or standard behind them.
If a parameter you expect to be documented has no icon, it simply has no registry entry yet — the field still works exactly as before.