Termite Colony Size & Risk Assessment Calculator

ANA›Life Services Authority›National Calculator Authority›Termite Colony Size & Risk Assessment Calculator

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Termite Colony Size & Risk Assessment Calculator

Estimate termite colony population and assess the risk of structural damage based on species, colony age, moisture levels, and wood availability.

Termite Species

Subterranean (Reticulitermes spp.) Formosan Subterranean (Coptotermes formosanus) Drywood (Incisitermes spp.) Dampwood (Zootermopsis spp.)

Colony Age (years)

Soil/Wood Moisture Level (%)

Average Temperature (°F)

Available Wood/Cellulose Material (sq ft)

Structure Type

Wood Frame Home Slab Foundation Crawlspace Foundation Basement Foundation

Calculate

function terCalc() { var species = document.getElementById('ter-species').value; var age = parseFloat(document.getElementById('ter-age').value); var moisture = parseFloat(document.getElementById('ter-moisture').value); var temp = parseFloat(document.getElementById('ter-temp').value); var wood = parseFloat(document.getElementById('ter-wood').value); var structure = document.getElementById('ter-structure').value;

// --- Validation --- if (isNaN(age) || age 50) { document.getElementById('ter-result').innerHTML = 'Please enter a valid colony age between 1 and 50 years.'; return; } if (isNaN(moisture) || moisture 80) { document.getElementById('ter-result').innerHTML = 'Please enter a valid moisture level between 5% and 80%.'; return; } if (isNaN(temp) || temp 110) { document.getElementById('ter-result').innerHTML = 'Please enter a valid temperature between 40°F and 110°F.'; return; } if (isNaN(wood) || wood 10000) { document.getElementById('ter-result').innerHTML = 'Please enter available wood area between 10 and 10,000 sq ft.'; return; }

// --- Species Parameters --- // baseGrowthRate: workers per year in ideal conditions // maxColonySize: biological ceiling // woodConsumption: lbs of wood per 1000 workers per year var speciesParams = { subterranean: { baseSize: 60000, growthRate: 0.35, maxSize: 500000, woodPerK: 13.0, label: 'Subterranean' }, formosan: { baseSize: 350000, growthRate: 0.50, maxSize: 8000000, woodPerK: 31.0, label: 'Formosan Subterranean' }, drywood: { baseSize: 2500, growthRate: 0.15, maxSize: 10000, woodPerK: 4.5, label: 'Drywood' }, dampwood: { baseSize: 4000, growthRate: 0.18, maxSize: 20000, woodPerK: 6.0, label: 'Dampwood' } };

var sp = speciesParams[species];

// --- Colony Size Estimation --- // Logistic growth model: N(t) = K / (1 + ((K - N0)/N0) * e^(-r*t)) // N0 = initial founding pair ~100 workers equivalent // K = carrying capacity (min of maxSize and wood-limited capacity) var N0 = 100; var K = sp.maxSize;

// Wood-limited carrying capacity: 1 sq ft of structural wood ≈ 0.5 lbs // woodPerK lbs consumed per 1000 workers per year; sustainable if annual consumption 0 ? woodLimitedK : K);

// Moisture factor (optimal ~20-30% for subterranean; drywood prefers = 25 ? 1.0 : Math.max(0.2, moisture / 25); } else { // Subterranean: optimal 15-30% if (moisture >= 15 && moisture = 75 && temp 0) { yearsToSignificantDamage = damageThresholdLbs / annualWoodLbs; } else { yearsToSignificantDamage = Infinity; }

// --- Structure Vulnerability Factor --- var structureFactors = { wood_frame: { factor: 1.0, label: 'Wood Frame Home' }, slab: { factor: 0.55, label: 'Slab Foundation' }, crawlspace: { factor: 1.20, label: 'Crawlspace Foundation' }, basement: { factor: 0.75, label: 'Basement Foundation' } }; var sf = structureFactors[structure];

// --- Risk Score (0-100) --- // Weighted composite: colony size (40%), moisture (25%), temp (15%), structure (20%) var colonySizeScore = Math.min(100, (colonySize / sp.maxSize) * 100); var moistureScore = moistureFactor * 100; var tempScore = tempFactor * 100; var structureScore = sf.factor * 83.3; // normalize 1.2 -> 100

var riskScore = Math.round( (colonySizeScore * 0.40) + (moistureScore * 0.25) + (tempScore * 0.15) + (structureScore * 0.20) ); riskScore = Math.min(100, Math.max(0, riskScore));

// --- Risk Level --- var riskLevel, riskColor, riskAction; if (riskScore 50'; }

// --- Output --- var html = '### Results '; html += ''; html += 'Species' + sp.label + ''; html += 'Estimated Colony Size' + fmt(colonySize) + ' workers'; html += 'Annual Wood Consumption' + annualWoodLbs.toFixed(1) + ' lbs/yr ≈ ' + linearFeet2x4.toFixed(0) + ' linear ft of 2×4'; html += 'Years to Significant Damage' + fmtD(yearsToSignificantDamage) + ' years'; html += 'Moisture Factor' + (moistureFactor * 100).toFixed(0) + '% of optimal'; html += 'Temperature Factor' + (tempFactor * 100).toFixed(0) + '% of optimal'; html += 'Structure Type' + sf.label + ''; html += '';

html += ''; html += 'Risk Level: ' + riskLevel + ' (' + riskScore + '/100)'; html += 'Recommended Action: ' + riskAction + ''; html += '';

html += ''; html += 'Estimated Potential Repair Cost Range: $' + fmt(baseCostLow) + ' – $' + fmt(baseCostHigh); html += ' (varies by region, extent of damage, and treatment method)'; html += '';

document.getElementById('ter-result').innerHTML = html; }

#### Formulas Used

Colony Size — Logistic Growth Model: N(t) = K / (1 + ((K − N₀) / N₀) × e−r·t) Where: N₀ = 100 (founding workers), K = carrying capacity (species max or wood-limited), r = adjusted growth rate = r_base × moisture_factor × temperature_factor, t = colony age (years).

Wood-Limited Carrying Capacity: K_wood = (Available Wood lbs × 0.05 / Wood Consumption per 1,000 workers) × 1,000,000 Assumes sustainable colony consumes ≤ 5% of available wood annually.

Annual Wood Consumption: Wood (lbs/yr) = (Colony Size / 1,000) × Species Wood Rate (lbs per 1,000 workers/yr)

Risk Score (0–100): Risk = 0.40 × Colony Size Score + 0.25 × Moisture Score + 0.15 × Temperature Score + 0.20 × Structure Score

#### Assumptions & References

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References

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