Structural Drying Equipment Placement Calculator

ANA›Life Services Authority›National Calculator Authority›Structural Drying Equipment Placement Calculator

.calc-container { max-width: 640px; margin: 2rem 0; padding: 1.5rem; background: #fff; border: 1px solid #ddd; border-radius: 8px; box-shadow: 0 1px 3px rgba(0,0,0,0.06); font-family: system-ui, -apple-system, sans-serif; } .calc-container h3 { font-family: Georgia, serif; font-size: 1.15rem; color: #1a1a1a; margin-bottom: 1rem; padding-bottom: 0.5rem; border-bottom: 2px solid var(--ac, #3d5a80); } .calc-row { display: flex; align-items: center; gap: 0.75rem; margin-bottom: 0.75rem; flex-wrap: wrap; } .calc-row label { min-width: 160px; font-size: 0.9rem; color: #333; font-weight: 500; } .calc-row input[type="number"], .calc-row select { flex: 1; min-width: 120px; max-width: 200px; padding: 0.5rem 0.6rem; border: 1px solid #ccc; border-radius: 4px; font-size: 0.9rem; font-family: system-ui, sans-serif; color: #1a1a1a; background: #fafaf8; } .calc-row input:focus, .calc-row select:focus { outline: none; border-color: var(--ac, #3d5a80); box-shadow: 0 0 0 2px rgba(26,74,138,0.12); } .calc-row .unit { font-size: 0.82rem; color: #888; min-width: 30px; } .calc-btn { display: inline-block; margin-top: 0.5rem; padding: 0.55rem 1.5rem; background: var(--ac, #3d5a80); color: #fff; border: none; border-radius: 4px; font-size: 0.9rem; font-weight: 600; cursor: pointer; font-family: system-ui, sans-serif; } .calc-btn:hover { opacity: 0.9; } .calc-result { margin-top: 1.25rem; padding: 1rem 1.25rem; background: #f0f6fc; border-left: 3px solid var(--ac, #3d5a80); border-radius: 0 6px 6px 0; display: none; } .calc-result.visible { display: block; } .calc-result-label { font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.06em; color: #666; margin-bottom: 0.25rem; } .calc-result-value { font-size: 1.6rem; font-weight: 700; color: var(--ac, #3d5a80); } .calc-result-detail { font-size: 0.85rem; color: #555; margin-top: 0.5rem; line-height: 1.5; } .calc-note { margin-top: 1rem; font-size: 0.8rem; color: #888; font-style: italic; } .calc-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 0.75rem; margin-top: 0.75rem; } .calc-grid-item { padding: 0.6rem 0.8rem; background: #f8f9fa; border-radius: 4px; border: 1px solid #eee; } .calc-grid-item .label { font-size: 0.75rem; color: #888; text-transform: uppercase; letter-spacing: 0.04em; } .calc-grid-item .value { font-size: 1.1rem; font-weight: 600; color: #1a1a1a; } @media (max-width: 720px) { .calc-row { flex-direction: column; align-items: flex-start; gap: 0.3rem; } .calc-row label { min-width: auto; } .calc-row input[type="number"], .calc-row select { max-width: 100%; width: 100%; } .calc-grid { grid-template-columns: 1fr; } } .calc-chart { margin: 1rem 0; text-align: center; } .calc-chart svg { max-width: 100%; height: auto; } .calc-chart-legend { display: flex; flex-wrap: wrap; justify-content: center; gap: 0.6rem 1.2rem; margin-top: 0.6rem; font-size: 0.8rem; color: #555; } .calc-chart-legend span { display: inline-flex; align-items: center; gap: 0.3rem; } .calc-chart-legend i { display: inline-block; width: 10px; height: 10px; border-radius: 2px; font-style: normal; } .calc-related { max-width: 640px; margin: 2rem 0 1rem; padding: 1.25rem 1.5rem; background: #f8f9fa; border: 1px solid #e8e8e8; border-radius: 8px; } .calc-related h3 { font-family: Georgia, serif; font-size: 1rem; color: #1a1a1a; margin: 0 0 0.75rem; padding-bottom: 0.4rem; border-bottom: 2px solid var(--ac, #3d5a80); } .calc-related-list { list-style: none; padding: 0; margin: 0 0 0.75rem; display: grid; grid-template-columns: 1fr 1fr; gap: 0.4rem 1.5rem; } .calc-related-list li a { font-size: 0.88rem; color: var(--ac, #3d5a80); text-decoration: none; } .calc-related-list li a:hover { text-decoration: underline; } .calc-browse-all { margin: 0.5rem 0 0; font-size: 0.9rem; font-weight: 600; } .calc-browse-all a { color: var(--ac, #3d5a80); text-decoration: none; } .calc-browse-all a:hover { text-decoration: underline; } @media (max-width: 720px) { .calc-related-list { grid-template-columns: 1fr; } }

Structural Drying Equipment Placement Calculator

Calculate the number of air movers and dehumidifiers required for structural drying based on IICRC S500 standards, affected area, and moisture conditions.

Room/Area Length (ft)

Room/Area Width (ft)

Ceiling Height (ft)

Water Damage Class

Class 1 – Minimal absorption (e.g. partial floor) Class 2 – Significant absorption (e.g. full floor + walls <24 in) Class 3 – Greatest absorption (e.g. walls, ceilings, insulation) Class 4 – Specialty drying (hardwood, concrete, plaster)

Number of Affected Surfaces

1 surface (floor only) 2 surfaces (floor + 1 wall) 3 surfaces (floor + 2 walls) 4 surfaces (floor + 3 walls) 5 surfaces (floor + 4 walls) 6 surfaces (floor + 4 walls + ceiling)

Indoor Humidity – Grains Per Pound (GPP)

Typical dry air: ~50 GPP | Wet structure: 100–200+ GPP

Outdoor Humidity – Grains Per Pound (GPP)

Use psychrometric chart or weather data

Indoor Temperature (°F)

Calculate Equipment Placement

function sdepCalc() { var length = parseFloat(document.getElementById('sdep_length').value); var width = parseFloat(document.getElementById('sdep_width').value); var height = parseFloat(document.getElementById('sdep_height').value); var waterClass = parseInt(document.getElementById('sdep_water_class').value); var surfaces = parseInt(document.getElementById('sdep_affected_surfaces').value); var gppIndoor = parseFloat(document.getElementById('sdep_gpp_indoor').value); var gppOutdoor = parseFloat(document.getElementById('sdep_gpp_outdoor').value); var temp = parseFloat(document.getElementById('sdep_temp').value);

var errors = []; if (isNaN(length) || length 30) errors.push("Ceiling height must be between 6 and 30 ft."); if (isNaN(gppIndoor) || gppIndoor 300) errors.push("Indoor GPP must be between 30 and 300."); if (isNaN(gppOutdoor) || gppOutdoor 300) errors.push("Outdoor GPP must be between 20 and 300."); if (isNaN(temp) || temp 100) errors.push("Temperature must be between 50°F and 100°F.");

if (errors.length > 0) { document.getElementById('sdep_result').innerHTML = 'Please fix the following:' + errors.map(function(e){ return ''; }).join('') + ''; return; }

// ── Core Calculations ──────────────────────────────────────────────────────

// Floor area and cubic volume var floorArea = length * width; // ft² var cubicVolume = floorArea * height; // ft³

// ── AIR MOVERS (IICRC S500 Formula) ─────────────────────────────────────── // Base rule: 1 air mover per 50–100 ft² of affected floor area // Class multiplier adjusts density; surface count adds perimeter movers var classMoverMultiplier = { 1: 0.010, 2: 0.015, 3: 0.020, 4: 0.025 }; var moverDensity = classMoverMultiplier[waterClass]; // movers per ft²

// Base air movers from floor area var baseMoversByArea = Math.ceil(floorArea * moverDensity);

// Additional movers for affected wall surfaces (1 mover per 16 linear ft of wall) var perimeter = 2 * (length + width); var wallMoverFraction = (surfaces - 1) / 5; // proportion of walls affected (0–1) var wallMovers = Math.ceil((perimeter * wallMoverFraction) / 16);

// Ceiling mover: add 1 per 200 ft² if ceiling affected (surfaces == 6) var ceilingMovers = (surfaces === 6) ? Math.ceil(floorArea / 200) : 0;

var totalAirMovers = baseMoversByArea + wallMovers + ceilingMovers; totalAirMovers = Math.max(totalAirMovers, 1); // minimum 1

// ── DEHUMIDIFIERS (IICRC S500 / LGR Formula) ────────────────────────────── // Evaporation rate (pints/day) = Volume (ft³) × Class factor × GPP differential factor // Class evaporation factors (pints/day per ft³): var classEvapFactor = { 1: 0.00040, 2: 0.00080, 3: 0.00120, 4: 0.00160 };

// GPP differential: ratio of indoor to target (50 GPP = dry standard) var targetGPP = 50; var gppDiff = Math.max(gppIndoor - targetGPP, 0);

// Temperature correction factor (dehumidifier efficiency drops below 70°F) var tempFactor = (temp >= 70) ? 1.0 : (temp >= 60) ? 0.85 : 0.70;

// Total moisture to remove (pints/day) // Formula: V × classFactor × (gppDiff / 100) × surfaces_factor × tempFactor var surfacesFactor = 1 + (surfaces - 1) * 0.15; // each extra surface adds 15% load var moistureLoad = cubicVolume * classEvapFactor[waterClass] * (gppDiff / 100 + 1) * surfacesFactor * tempFactor;

// Standard LGR dehumidifier capacity: 150 pints/day at AHAM conditions // Adjusted capacity at actual conditions using simplified correction: // Adjusted cap = 150 × tempFactor × (gppIndoor / 100) var dehum_capacity_pints = 150 * tempFactor * Math.min(gppIndoor / 100, 2.0); dehum_capacity_pints = Math.max(dehum_capacity_pints, 50); // floor at 50 pints/day

var totalDehumidifiers = Math.ceil(moistureLoad / dehum_capacity_pints); totalDehumidifiers = Math.max(totalDehumidifiers, 1); // minimum 1

// ── AIR CHANGES PER HOUR CHECK ───────────────────────────────────────────── // Each air mover moves ~300 CFM; target ≥ 4 ACH for drying var totalCFM = totalAirMovers * 300; var achAchieved = (totalCFM * 60) / cubicVolume; var achStatus = achAchieved >= 4 ? "✅ Adequate" : "⚠️ Below recommended 4 ACH – consider adding air movers";

// ── PLACEMENT STRATEGY ──────────────────────────────────────────────────── var placementNotes = []; placementNotes.push("Place air movers at a 45° angle against affected walls, 2–4 inches from the baseboard."); if (surfaces >= 3) placementNotes.push("Use a daisy-chain (vortex) pattern around the room perimeter for wall drying."); if (surfaces === 6) placementNotes.push("Direct at least " + ceilingMovers + " air mover(s) upward toward the ceiling using a ceiling attachment or angled placement."); if (waterClass === 4) placementNotes.push("Class 4: Use desiccant dehumidifiers or supplemental heat for specialty materials."); placementNotes.push("Position dehumidifier(s) centrally to capture moisture-laden air from all air movers."); if (gppIndoor > gppOutdoor + 20) { placementNotes.push("Indoor GPP significantly exceeds outdoor – keep structure closed; do NOT ventilate."); } else { placementNotes.push("Outdoor GPP is close to indoor – evaluate whether controlled ventilation may assist drying."); }

// ── Monitoring Recommendation ───────────────────────────────────────────── var monitoringDays = waterClass + 1; // rough estimate: Class 1 = 2 days, Class 4 = 5 days

// ── Output ──────────────────────────────────────────────────────────────── var html = '### Equipment Placement Results '; html += ''; html += 'ParameterValue'; html += 'Floor Area' + floorArea.toFixed(1) + ' ft²'; html += 'Cubic Volume' + cubicVolume.toFixed(0) + ' ft³'; html += 'GPP Differential (Indoor − 50 target)' + gppDiff.toFixed(0) + ' GPP'; html += 'Moisture Load Estimate' + moistureLoad.toFixed(1) + ' pints/day'; html += 'Adjusted Dehumidifier Capacity' + dehum_capacity_pints.toFixed(0) + ' pints/day per unit'; html += 'Air Changes Per Hour (ACH)' + achAchieved.toFixed(1) + ' ACH – ' + achStatus + ''; html += '';

html += ''; html += '### 📦 Equipment Required '; html += 'Air Movers: ' + totalAirMovers + ''; html += ' (Floor: ' + baseMoversByArea + ' | Walls: ' + wallMovers + ' | Ceiling: ' + ceilingMovers + ')

'; html += 'Dehumidifiers (LGR): ' + totalDehumidifiers + '

'; html += '';

html += '#### 📍 Placement Strategy '; placementNotes.forEach(function(n){ html += ''; }); html += '';

html += '#### 📅 Monitoring '; html += 'Check moisture readings every 24 hours. Expected drying time for Class ' + waterClass + ': approximately ' + monitoringDays + '–' + (monitoringDays + 2) + ' days under controlled conditions. Adjust equipment if GPP does not drop ≥10% per day.

document.getElementById('sdep_result').innerHTML = html; }

#### Formulas Used

Air Movers: Air Movers = ⌈Floor Area × Class Density⌉ + ⌈(Perimeter × Wall Fraction) ÷ 16⌉ + Ceiling Movers Class Density: Class 1 = 0.010, Class 2 = 0.015, Class 3 = 0.020, Class 4 = 0.025 movers/ft²

Moisture Load (pints/day): Load = Volume (ft³) × Class Evaporation Factor × (GPP Differential ÷ 100 + 1) × Surfaces Factor × Temp Factor Class Evap Factors: Class 1 = 0.00040, Class 2 = 0.00080, Class 3 = 0.00120, Class 4 = 0.00160 Surfaces Factor = 1 + (Surfaces − 1) × 0.15 | Temp Factor: ≥70°F = 1.0, 60–69°F = 0.85, <60°F = 0.70

Dehumidifiers: Adjusted Capacity = 150 pints/day × Temp Factor × (Indoor GPP ÷ 100) Dehumidifiers = ⌈Moisture Load ÷ Adjusted Capacity⌉

Air Changes Per Hour (ACH): ACH = (Air Movers × 300 CFM × 60 min) ÷ Volume (ft³) | Target: ≥ 4 ACH

#### Assumptions & References

Based on IICRC S500 Standard for Professional Water Damage Restoration (5th Edition).
Each air mover is assumed to deliver approximately 300 CFM at operating conditions.
LGR dehumidifiers rated at 150 pints/day under AHAM standard conditions (80°F, 60% RH); adjusted for actual temperature and humidity.
Target indoor GPP for structural drying: 50 GPP (≈ 40% RH at 70°F).

Structural Drying Equipment Placement Calculator

Structural Drying Equipment Placement Calculator

More Calculators

Read Next

References

Structural Drying Equipment Placement Calculator

Structural Drying Equipment Placement Calculator

More Calculators

Read Next

References

Related Authorities