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Plant Engineering Calculator

Updated Sep 18, 2026

Steam Trap Survey Loss Calculator — Failed Traps, Steam, Energy & Annual Cost

Turn a steam-trap survey into a fleet-level loss estimate. Model failed-open and leaking traps separately, apply a measured or engineering leak rate, then calculate failed trap count, steam loss, thermal loss, annual tonnes, annual cost and repair-payback screening.

Live calculationWorking shownPrivate in browser

Inputs

Results

Failed open 10.0 traps
Leaking 8.0 traps
Survey failure rate 18.0%
Equivalent full-leak traps 13.20
Steam loss 105.60 kg/h
Annual loss 844.8 t
Thermal loss 645333 kWh/year
Avoidable steam cost $2112000/year
Repair budget $90000
Survey + repair program $105000/year
Net first-year benefit $2007000
First-year ROI 1911.4%
Simple payback 0.6 months
More actions

Shared links reopen these inputs. Recent and saved calculations stay in this browser unless you clear site data.

Formula

failedOpen=N×FO%; leaking=N×L%; equivalent full-leak traps=failedOpen+leaking×leakFraction; steam loss=equivalent traps×full-open leak rate; annual tonnes=kg/h×hours/1000.

Your calculation, step by step

These steps use the values currently entered above so the result can be checked independently.

  1. 1.Failed-open traps = 100 × 10.00% = 10.00; leaking traps = 100 × 8.00% = 8.00.
  2. 2.Equivalent full-leak population = 10.00 + 8.00 × 40.00% = 13.200 traps.
  3. 3.Steam loss = 13.200 × 8.000 = 105.600 kg/h.
  4. 4.Annual steam loss = 105.600 × 8000 ÷ 1000 = 844.800 t; thermal loss = 105.600 × 8000 × 2750.00 ÷ 3600 = 645333.3 kWh.
  5. 5.Avoidable steam value = 844.800 × $2500.00/t = $2112000.00; survey + repair program = (18.00 traps × $5000.00) + $15000.00 = $105000.00.

How to use this calculator

  1. Enter measured or design values using the units shown beside each field.
  2. Review the live results and the substituted calculation steps before using the estimate.
  3. Check the assumptions below, then continue to a related calculator when the next engineering decision needs another model.

Worked example

For 100 traps with 10% failed open, 8% leaking at 40% severity and an 8 kg/h full-open leak estimate, the equivalent full-leak population is 13.2 traps before annualizing steam, energy and cost.

Assumptions and limits

  • Full-open leak rate should come from a validated trap survey, orifice-flow method, OEM data or engineering estimate.
  • Leaking-trap severity is uncertain; keep the entered leak fraction tied to the survey method instead of assuming every leaking trap is fully blown.
  • This calculator quantifies survey economics; ultrasonic/temperature testing is still required to diagnose individual traps.

How to interpret the result

Treat the primary result as an engineering screening value, then use the secondary outputs to understand scale, energy or operating impact. Confirm site measurements, equipment limits and applicable standards before making a design or control change.

Questions engineers ask

Why are failed-open and leaking traps modeled separately?

A failed-open trap can pass live steam very differently from a trap diagnosed as leaking or rapidly cycling. The survey should classify condition, and the entered leaking-severity fraction prevents every imperfect trap from being treated as a full-open failure.

Where should the full-open leak kg/h value come from?

Use a validated orifice/steam-flow method, OEM data or survey engineering estimate at the actual pressure and trap condition. Steam-trap specialists warn that arbitrary “typical loss per trap” values can be misleading.

Why include survey and repair cost instead of only lost steam?

A trap-management program is an economic decision as well as an energy calculation. The owner compares avoidable steam value with the entered survey/repair budget, but individual trap diagnosis still requires appropriate ultrasonic, temperature and application checks.

Continue the calculation

Use the next calculator in the same engineering workflow instead of restarting from search.

steam trap sizingsteam leak coststeam cost
Methodology. MAXScanner shows the governing formula, entered values and calculation outputs so the estimate is auditable. The calculator is a screening aid; assumptions and equipment-specific limits remain part of the engineering review.