Home / Engineering Data
Reference
Engineering Data
Specifications, formulas and material tables. Published in full, free to use, and free to check against your own numbers — including if you end up buying from someone else.
Heater Sizing Calculator
Working calculator plus the formula it uses. Kilowatts for heat-up, an estimate for standing losses, and a safety margin. Includes the flow-heating form for circulation heaters and worked examples you can check by hand.
kW = (gal × 8.34 × SG × Cp × ΔT) ÷ (3412 × hours)
Sheath Material Selection
Nine sheath materials — 316 stainless, Incoloy 800, Monel, nickel, titanium, carbon steel, PTFE-coated, quartz and Hastelloy — against dozens of liquids, with what each one fails at as well as what it survives.
The only part the liquid touches
Watt Density Limits
Maximum W/in² by liquid, from 90 for clean water down to 5 for asphalt. How to convert a watt density limit into required element surface area, and why a correct kilowatt calculation still burns out elements without it.
Factor of ten between water and heavy oil
Why Heaters Fail
Eight failure modes with what each one looks like on the element you pulled out. Dry firing, excessive watt density, scale, wrong sheath, coking, moisture ingress, cycling fatigue and voltage mismatch.
Diagnose from the failed part
Voltage & Controls
What happens when a heater is run on the wrong voltage, single versus three phase, contactor versus SCR control, sensor type and placement, and the protection scheme that prevents most failures.
Wrong voltage is a squared error, not a linear one
Why publish all of it
Because the alternative is asking you to trust a number you cannot see. If you can check the sizing, the material and the watt density yourself, the quote either holds up or it does not — and that is a better basis for buying a heater than a phone call.
Quick reference
| Item | Value or rule | Detail |
|---|---|---|
| Tank heat-up | kW = (gal × 8.34 × SG × Cp × ΔT°F) ÷ (3412 × hours) | Sizing |
| Flow heating | kW = (GPM × 500 × SG × Cp × ΔT°F) ÷ 3412 | Sizing |
| Element area needed | in² = (watts) ÷ (max W/in²) | Watt density |
| Power on wrong voltage | Actual W = rated W × (applied V ÷ rated V)² | Controls |
| Clean water max | 60 – 90 W/in² | Watt density |
| Heavy oil max | 6 – 10 W/in² | Watt density |
| Reducing acids | PTFE-coated or quartz; titanium is attacked | Materials |
| Oxidizing acids | Titanium performs well | Materials |
| Chloride-bearing liquids | Titanium; 300 series stainless stress-cracks | Materials |
| Concentrated caustic | Nickel or Monel 400 | Materials |
| Most common sudden failure | Dry firing — prevent with a low-level cutoff | Failures |
Guideline values for typical conditions. Concentration, temperature and contaminants shift the material answers; confirm against your own analysis before ordering.
Checked the numbers and want it built?
Send what you worked out and we will verify it against the tank before quoting. If your numbers are right we will say so.