Enter the width of the glass pane in millimeters (mm).
Enter the height of the glass pane in millimeters (mm).
Approximate density of glass in kg/m³. Standard is ~2500 kg/m³.
2 (General Use)
3 (Moderate Load)
4 (High Load/Risk)
Select a safety factor based on application and risk.
Calculation Results
—
—
Area (m²)
—
Volume (m³)
—
Weight (kg)
—
Max Load (kg)
Formula Used:
Weight = Glass Area × Glass Thickness × Glass Density
Max Load Capacity = Glass Weight × Safety Factor
Glass Weight vs. Load Capacity Across Thicknesses
Thickness (mm)
Approx. Weight (kg/m²)
Min. Safety Load (kg/m²)
Max. Recommended Load (kg/m²)
What is a Glass Weight Load Calculator?
A Glass Weight Load Calculator is a specialized tool designed to estimate the weight of a glass pane and determine its safe load-bearing capacity. Glass, while seemingly delicate, possesses significant strength when properly supported and selected for its intended application. This calculator helps engineers, architects, designers, and DIY enthusiasts understand the structural implications of using glass in various contexts, from balustrades and shower screens to tabletops and structural glazing. It takes into account key physical properties of the glass, such as its dimensions and density, along with a crucial safety factor to prevent failure. Understanding the weight and load capacity is paramount for ensuring safety and durability in any glass installation, making the glass weight load calculator an indispensable resource for professionals and homeowners alike.
Who should use it:
Architects and Building Designers: To specify appropriate glass types for structural elements.
Engineers: For structural analysis and ensuring compliance with building codes.
Fabricators and Installers: To determine handling procedures and support requirements.
DIY Enthusiasts: For planning projects involving custom glass furniture or fixtures.
Safety Officers: To assess risks in environments where glass is used under load.
Common misconceptions:
Glass is too fragile for structural applications: Modern engineered glass is exceptionally strong.
All glass weights are the same: Weight varies significantly with thickness and type.
Load capacity is solely determined by thickness: It's a complex interplay of thickness, area, support conditions, and glass type.
A higher safety factor always means overkill: It's essential for mitigating risk in critical applications.
Glass Weight Load Calculator Formula and Mathematical Explanation
The calculation performed by the glass weight load calculator is based on fundamental physics principles related to volume, density, and safety margins. The process involves determining the volume of the glass pane, multiplying it by the material's density to find its weight, and then applying a safety factor to establish a maximum permissible load.
Step-by-Step Derivation:
Calculate Glass Area: The surface area of the glass pane is found by multiplying its width by its height. This gives the total surface exposed.
Calculate Glass Volume: The volume is then calculated by multiplying the area by the glass thickness. To ensure consistent units, all dimensions are converted to meters.
Calculate Glass Weight: The weight of the glass is determined by multiplying its volume by its density. Density is typically given in kilograms per cubic meter (kg/m³).
Calculate Maximum Load Capacity: A safety factor is applied to the calculated weight. This factor accounts for uncertainties in material properties, external forces (like wind or impact), and variations in installation. The result is the maximum load the glass can safely withstand under the specified conditions.
Variable Explanations:
Understanding the variables is key to using the glass weight load calculator accurately:
Glass Thickness (t): The depth of the glass pane. Thicker glass is generally stronger and heavier.
Glass Width (w): One dimension of the glass pane's surface.
Glass Height (h): The other dimension of the glass pane's surface.
Glass Density (ρ): The mass per unit volume of the glass material. This is a material property.
Safety Factor (SF): A multiplier applied to the calculated weight to determine the safe load capacity. It accounts for potential overloads and material imperfections.
Variables Table:
Variable
Meaning
Unit
Typical Range
Glass Thickness (t)
Thickness of the glass pane
mm
4 – 25+
Glass Width (w)
Width of the glass pane
mm
100 – 3000+
Glass Height (h)
Height of the glass pane
mm
100 – 3000+
Glass Density (ρ)
Mass per unit volume of glass
kg/m³
~2500 (Standard Float Glass)
Safety Factor (SF)
Factor to ensure safe load bearing
Unitless
2 – 5 (Commonly used)
Glass Area (A)
Surface area of the glass
m²
Calculated
Glass Volume (V)
Volume of the glass pane
m³
Calculated
Glass Weight (W)
Total mass of the glass pane
kg
Calculated
Max Load Capacity (MLC)
Maximum safe load the glass can bear
kg
Calculated
Practical Examples (Real-World Use Cases)
Let's explore practical scenarios where the glass weight load calculator is essential:
Example 1: Glass Balustrade
An architect is designing a modern interior staircase with glass balustrades. They need to determine the weight and safety load for a specific glass panel.
Inputs:
Glass Thickness: 12 mm
Glass Width: 1200 mm
Glass Height: 900 mm
Glass Density: 2500 kg/m³
Safety Factor: 3 (for moderate public traffic)
Calculator Output:
Glass Area: 1.08 m²
Glass Volume: 0.01296 m³
Glass Weight: 32.4 kg
Max Load Capacity: 97.2 kg
Interpretation: The 12mm glass panel weighs approximately 32.4 kg. The calculator indicates a maximum safe load capacity of 97.2 kg. This figure helps engineers verify that the support structure and the glass itself can safely handle expected loads, including potential human impact, wind forces, and the glass's own weight, while maintaining a sufficient safety margin. This is crucial for structural analysis.
Example 2: Heavy Glass Tabletop
A furniture designer wants to create a statement coffee table using a thick glass top. They need to ensure the glass can support the weight of objects placed on it and its own weight.
Inputs:
Glass Thickness: 19 mm
Glass Width: 1500 mm
Glass Height: 800 mm
Glass Density: 2500 kg/m³
Safety Factor: 2 (for a controlled home environment)
Calculator Output:
Glass Area: 1.2 m²
Glass Volume: 0.0228 m³
Glass Weight: 57 kg
Max Load Capacity: 114 kg
Interpretation: A 19mm thick glass top of these dimensions weighs about 57 kg. The glass weight load calculator suggests a maximum load capacity of 114 kg. This means the tabletop can safely support an additional 57 kg of distributed weight (114 kg total capacity – 57 kg glass weight), ensuring it can handle decorative items, books, or even someone leaning on it, without risk of breakage. Proper material selection is vital here.
How to Use This Glass Weight Load Calculator
Using our glass weight load calculator is straightforward. Follow these steps to get accurate results for your project:
Input Glass Dimensions: Enter the thickness, width, and height of the glass pane in millimeters (mm) into the respective fields. Ensure these measurements are precise.
Specify Glass Density: Input the density of the glass. For standard float glass, 2500 kg/m³ is a common value. For specialized glass types, consult the manufacturer's specifications.
Select Safety Factor: Choose an appropriate safety factor from the dropdown menu. Higher values offer greater security but might lead to over-specification. Consider the application's risk level, potential impact, and relevant building codes. A safety factor of 2 is typical for furniture, while 3 or 4 is recommended for structural or high-traffic areas like balustrades.
Calculate: Click the "Calculate" button. The calculator will instantly process your inputs.
Review Results:
Primary Result (Max Load Capacity): This is the highlighted main figure, indicating the maximum weight the glass can safely support in kilograms (kg).
Intermediate Values: You'll see the calculated Area (m²), Volume (m³), Weight (kg), and the Max Load Capacity (kg).
Table and Chart: These provide a broader context, showing how weight and load capacity vary with different glass thicknesses.
Formula Explanation: A clear breakdown of how the results were derived.
Decision Making: Compare the calculated Max Load Capacity against the expected loads for your application. Ensure the capacity significantly exceeds the anticipated weight to maintain a safety margin. If the capacity is insufficient, consider increasing the glass thickness, adjusting the dimensions, or choosing a different glass type.
Reset: To start over with default values, click the "Reset" button.
Copy Results: Use the "Copy Results" button to easily transfer the main result, intermediate values, and key assumptions to your notes or documents.
Key Factors That Affect Glass Weight Load Results
While the glass weight load calculator provides essential estimations, several real-world factors can influence the actual load capacity and behaviour of glass:
Glass Thickness: This is the most critical factor. Doubling the thickness can significantly increase strength and weight, though not linearly. Thicker glass distributes stress more effectively.
Glass Area and Span: Larger glass panes, especially with longer unsupported spans, will sag more under their own weight and external loads. The calculator accounts for area, but the method of support (e.g., clamped edges vs. fully supported) is crucial in real-world engineering calculations beyond this basic estimator. This relates to structural analysis.
Type of Glass: The calculator assumes standard float glass density. However, toughened (tempered) glass, laminated glass, or heat-strengthened glass have different strength properties and failure modes. Toughened glass is significantly stronger than annealed glass and breaks into small, relatively harmless pieces. Laminated glass (two or more layers bonded with a polymer interlayer) offers enhanced safety and security, holding together when broken.
Support Conditions: How the glass is framed or supported is paramount. Glass supported on all four edges will handle load differently than glass supported only on two edges or point-supported. This calculator provides a general weight and load estimation, not a definitive structural engineering analysis, which requires detailed consideration of edge fixings and potential stress concentrations.
Environmental Factors: Extreme temperatures can affect glass properties slightly. Humidity typically has minimal impact on glass itself but can affect supporting materials. UV exposure can degrade sealants in laminated glass over very long periods.
Edge Quality and Processing: Chips, scratches, or imperfections on the edges of the glass can create stress points, significantly reducing its load-bearing capacity. Properly finished edges are crucial for structural integrity. This affects the material selection process.
Load Distribution: The calculator assumes a generally distributed load. Concentrated point loads can cause failure at much lower overall weights than uniformly distributed loads. The safety factor helps account for this, but specific engineering analysis is needed for critical point-load applications.
Glass Density Variations: While 2500 kg/m³ is standard, different types of glass (e.g., leaded glass, borosilicate glass) have varying densities. Using an inaccurate density will directly impact the weight and subsequent load calculations.
Frequently Asked Questions (FAQ)
What is the standard density of glass used in calculations?
The standard density for common float glass is approximately 2500 kg/m³. This value is used in the calculator by default but can be adjusted if you are working with a different type of glass with a known density.
What is a safety factor, and how do I choose one?
A safety factor is a multiplier applied to the calculated weight to determine the maximum safe load. It ensures the glass can withstand loads exceeding the expected minimum, accounting for uncertainties and potential overloads. For home applications like tabletops, a factor of 2 might suffice. For structural elements like balustrades or overhead glazing, factors of 3, 4, or even higher are often required by building codes and best practice for risk assessment.
Does the calculator account for wind load on glass?
This calculator primarily estimates the static weight and a general safe load capacity. It does not specifically calculate dynamic loads like wind pressure or impact forces. For applications exposed to significant wind loads (e.g., facades, railings), a specialized structural engineering analysis is required.
Can this calculator be used for laminated or toughened glass?
The calculator uses a standard density for float glass. While it can give an approximate weight for toughened or laminated glass (if their densities are similar), it does not inherently account for their increased strength or different failure characteristics. Toughened glass is significantly stronger, and laminated glass has safety benefits when broken. Specialized calculators or engineering consultations are recommended for these specific glass types when precise load capacity is critical.
How does the area affect the glass weight and load capacity?
The area directly impacts the total weight because weight is calculated as Volume (Area × Thickness) × Density. A larger area means more volume and thus more weight. Load capacity also increases with area, but the risk of deflection and potential for breakage under load also increases with larger spans.
What if my glass dimensions are not in millimeters?
The calculator requires input in millimeters (mm). If your measurements are in inches or other units, you will need to convert them to millimeters before entering them into the calculator. (1 inch = 25.4 mm).
Is the "Max Load Capacity" the total weight the glass can hold, or the additional weight?
The "Max Load Capacity" calculated is the total maximum weight the glass can safely support, including its own weight. For example, if the Max Load Capacity is 100 kg and the glass itself weighs 40 kg, it can support an additional 60 kg of applied load.
What are the limitations of this calculator?
This calculator provides a simplified estimation based on weight and a general safety factor. It does not replace a professional structural engineering analysis, which would consider factors like edge support, point loads, impact resistance, specific glass types (tempered, laminated), thermal stress, and complex environmental conditions. It is best used for preliminary assessments and understanding basic principles.
Understand structural loads in different building contexts.
var glassThicknessInput = document.getElementById('glassThickness');
var glassWidthInput = document.getElementById('glassWidth');
var glassHeightInput = document.getElementById('glassHeight');
var glassDensityInput = document.getElementById('glassDensity');
var safetyFactorInput = document.getElementById('safetyFactor');
var glassThicknessError = document.getElementById('glassThicknessError');
var glassWidthError = document.getElementById('glassWidthError');
var glassHeightError = document.getElementById('glassHeightError');
var glassDensityError = document.getElementById('glassDensityError');
var safetyFactorError = document.getElementById('safetyFactorError');
var primaryResultDiv = document.getElementById('primaryResult');
var glassAreaResult = document.getElementById('glassArea');
var glassVolumeResult = document.getElementById('glassVolume');
var glassWeightResult = document.getElementById('glassWeight');
var maxLoadCapacityResult = document.getElementById('maxLoadCapacity');
var chart = null;
var chartContext = null;
function validateInput(element, errorElement, min, max, isRequired = true) {
var value = parseFloat(element.value);
var errorMessage = ";
errorElement.style.display = 'none';
if (isRequired && (element.value === null || element.value === ")) {
errorMessage = 'This field is required.';
} else if (isNaN(value)) {
errorMessage = 'Please enter a valid number.';
} else if (value max) {
errorMessage = 'Value cannot be greater than ' + max + '.';
}
if (errorMessage) {
errorElement.textContent = errorMessage;
errorElement.style.display = 'block';
return false;
}
return true;
}
function calculateGlassLoad() {
var isValid = true;
isValid &= validateInput(glassThicknessInput, glassThicknessError, 0.1); // Minimum thickness of 0.1mm
isValid &= validateInput(glassWidthInput, glassWidthError, 1); // Minimum width of 1mm
isValid &= validateInput(glassHeightInput, glassHeightError, 1); // Minimum height of 1mm
isValid &= validateInput(glassDensityInput, glassDensityError, 1000); // Minimum density of 1000 kg/m³
// Safety factor validation is handled by select element default
if (!isValid) {
primaryResultDiv.textContent = 'ERR';
glassAreaResult.textContent = '–';
glassVolumeResult.textContent = '–';
glassWeightResult.textContent = '–';
maxLoadCapacityResult.textContent = '–';
return;
}
var thicknessMM = parseFloat(glassThicknessInput.value);
var widthMM = parseFloat(glassWidthInput.value);
var heightMM = parseFloat(glassHeightInput.value);
var density = parseFloat(glassDensityInput.value);
var safetyFactor = parseFloat(safetyFactorInput.value);
// Convert dimensions to meters for calculation
var thicknessM = thicknessMM / 1000;
var widthM = widthMM / 1000;
var heightM = heightMM / 1000;
// Calculations
var glassArea = widthM * heightM;
var glassVolume = glassArea * thicknessM;
var glassWeight = glassArea * density; // Weight per m² * area in m²
var maxLoadCapacity = glassWeight * safetyFactor;
// Display results
primaryResultDiv.textContent = maxLoadCapacity.toFixed(2);
glassAreaResult.textContent = glassArea.toFixed(3);
glassVolumeResult.textContent = glassVolume.toFixed(5);
glassWeightResult.textContent = glassWeight.toFixed(2);
maxLoadCapacityResult.textContent = maxLoadCapacity.toFixed(2);
updateGlassDataTableAndChart();
return true; // Indicate success
}
function resetCalculator() {
glassThicknessInput.value = 6;
glassWidthInput.value = 1000;
glassHeightInput.value = 1000;
glassDensityInput.value = 2500;
safetyFactorInput.value = 2;
glassThicknessError.style.display = 'none';
glassWidthError.style.display = 'none';
glassHeightError.style.display = 'none';
glassDensityError.style.display = 'none';
calculateGlassLoad();
}
function copyResults() {
var resultText = "Glass Weight Load Calculation Results:\n\n";
resultText += "—————————————-\n";
resultText += "Maximum Load Capacity: " + primaryResultDiv.textContent + " kg\n";
resultText += "—————————————-\n\n";
resultText += "Key Values:\n";
resultText += "Glass Area: " + glassAreaResult.textContent + " m²\n";
resultText += "Glass Volume: " + glassVolumeResult.textContent + " m³\n";
resultText += "Glass Weight: " + glassWeightResult.textContent + " kg\n";
resultText += "—————————————-\n\n";
resultText += "Assumptions:\n";
resultText += "Glass Thickness: " + glassThicknessInput.value + " mm\n";
resultText += "Glass Width: " + glassWidthInput.value + " mm\n";
resultText += "Glass Height: " + glassHeightInput.value + " mm\n";
resultText += "Glass Density: " + glassDensityInput.value + " kg/m³\n";
resultText += "Safety Factor: " + safetyFactorInput.options[safetyFactorInput.selectedIndex].text + " (" + safetyFactorInput.value + ")\n";
try {
navigator.clipboard.writeText(resultText).then(function() {
// Optional: Show a temporary confirmation message
var originalText = document.getElementById('copyButton').textContent;
document.getElementById('copyButton').textContent = 'Copied!';
setTimeout(function() {
document.getElementById('copyButton').textContent = originalText;
}, 1500);
}, function(err) {
console.error('Could not copy text: ', err);
alert('Failed to copy results. Please copy manually.');
});
} catch (e) {
console.error('Clipboard API not available: ', e);
alert('Clipboard API not available. Please copy results manually.');
}
}
function updateGlassDataTableAndChart() {
var dataTableBody = document.getElementById('glassDataTableBody');
dataTableBody.innerHTML = "; // Clear previous data
var baseThicknessMM = parseFloat(glassThicknessInput.value);
var baseWidthMM = parseFloat(glassWidthInput.value);
var baseHeightMM = parseFloat(glassHeightInput.value);
var baseDensity = parseFloat(glassDensityInput.value);
var baseSafetyFactor = parseFloat(safetyFactorInput.value);
var chartLabels = [];
var weightData = []; // Weight per m²
var loadData = []; // Min Safety Load per m²
var thicknessesToChart = [4, 6, 8, 10, 12, 15, 19, 25]; // Common thicknesses
for (var i = 0; i < thicknessesToChart.length; i++) {
var thickness = thicknessesToChart[i];
var thicknessM = thickness / 1000;
// Calculate for a 1m x 1m pane for table/chart consistency
var area1m2 = 1.0; // 1 m²
var weight1m2 = area1m2 * baseDensity; // Weight of 1 m² pane
var minLoad1m2 = weight1m2 * baseSafetyFactor; // Min load for 1 m² pane
chartLabels.push(thickness + ' mm');
weightData.push(weight1m2);
loadData.push(minLoad1m2);
var row = dataTableBody.insertRow();
var cellThickness = row.insertCell(0);
var cellWeight = row.insertCell(1);
var cellLoad = row.insertCell(2);
var cellMaxRecommendedLoad = row.insertCell(3); // Placeholder for illustrative purposes
cellThickness.textContent = thickness + ' mm';
cellWeight.textContent = weight1m2.toFixed(2);
cellLoad.textContent = minLoad1m2.toFixed(2);
cellMaxRecommendedLoad.textContent = (minLoad1m2 * 1.5).toFixed(2); // Example: Illustrative 'Max Recommended'
}
// Update Chart
if (!chartContext) {
chartContext = document.getElementById('loadCapacityChart').getContext('2d');
chart = new Chart(chartContext, {
type: 'bar', // Changed to bar for better comparison
data: {
labels: chartLabels,
datasets: [{
label: 'Approx. Weight (kg/m²)',
data: weightData,
backgroundColor: 'rgba(0, 74, 153, 0.6)', // Primary color variant
borderColor: 'rgba(0, 74, 153, 1)',
borderWidth: 1,
yAxisID: 'y-axis-weight'
}, {
label: 'Min. Safety Load (kg/m²)',
data: loadData,
backgroundColor: 'rgba(40, 167, 69, 0.6)', // Success color variant
borderColor: 'rgba(40, 167, 69, 1)',
borderWidth: 1,
yAxisID: 'y-axis-load'
}]
},
options: {
responsive: true,
maintainAspectRatio: false,
scales: {
x: {
title: {
display: true,
text: 'Glass Thickness (mm)'
}
},
'y-axis-weight': {
type: 'linear',
position: 'left',
title: {
display: true,
text: 'Weight (kg/m²)'
},
grid: {
drawOnChartArea: true, // Only draw grid lines for the left y-axis
},
ticks: {
beginAtZero: true
}
},
'y-axis-load': {
type: 'linear',
position: 'right',
title: {
display: true,
text: 'Load Capacity (kg/m²)'
},
ticks: {
beginAtZero: true
}
}
},
plugins: {
tooltip: {
callbacks: {
label: function(context) {
var label = context.dataset.label || '';
if (label) {
label += ': ';
}
if (context.parsed.y !== null) {
label += context.parsed.y.toFixed(2);
}
return label;
}
}
}
}
}
});
} else {
chart.data.labels = chartLabels;
chart.data.datasets[0].data = weightData;
chart.data.datasets[1].data = loadData;
chart.update();
}
}
// Initial calculation on load
document.addEventListener('DOMContentLoaded', function() {
// Add event listeners for real-time updates and validation
var inputs = [glassThicknessInput, glassWidthInput, glassHeightInput, glassDensityInput];
for (var i = 0; i < inputs.length; i++) {
inputs[i].addEventListener('input', calculateGlassLoad);
}
safetyFactorInput.addEventListener('change', calculateGlassLoad);
document.getElementById('resetButton').addEventListener('click', resetCalculator);
document.getElementById('copyButton').addEventListener('click', copyResults);
document.getElementById('calculateButton').addEventListener('click', calculateGlassLoad);
resetCalculator(); // Load with default values and perform initial calculation
});
// Basic Chart.js implementation (requires Chart.js library – assuming it's available globally or included elsewhere for this snippet)
// NOTE: For a truly self-contained solution, Chart.js would need to be included via CDN or embedded.
// Since the prompt asked for pure SVG or Canvas without external libraries, a simple Canvas drawing approach would be needed
// or a basic SVG structure. For demonstration, using Chart.js structure but acknowledging it's an external dependency.
// A truly self-contained version would manually draw bars/lines on canvas or build SVG elements.
// —- IMPORTANT NOTE FOR SELF-CONTAINED: —-
// If Chart.js is NOT available, the following function would need to be replaced
// with manual Canvas API drawing or SVG element creation to render the chart.
// For this example, we'll assume a basic Chart.js setup for clarity of intent.
// To make this fully standalone WITHOUT Chart.js:
// You'd need to remove the Chart object instantiation and write custom canvas drawing code here,
// calculating bar positions, heights, colors, and drawing axes manually.
// Placeholder for Chart.js library inclusion if needed, or manual drawing logic.
// In a real production environment, you'd include Chart.js via CDN:
//
// Since this is a single file, we'll proceed assuming it's available for the chart logic.
// If not, the chart section would need manual Canvas/SVG implementation.
// Add Chart.js library link if it's not expected to be globally available
// This is a critical assumption for the chart to render. If it MUST be purely native HTML/JS without any external library,
// then the canvas drawing needs to be implemented manually.
// For this specific request, assuming native canvas drawing capability is required without external libs:
// The `updateGlassDataTableAndChart` function currently relies on Chart.js.
// To meet the "NO external chart libraries" rule strictly:
// A manual canvas drawing function would replace the Chart.js instantiation and update logic.
// This would involve calculating coordinates, drawing rectangles for bars, lines for axes, and text labels.
// Given the complexity of manual canvas drawing for a responsive chart, and the common practice,
// let's refine `updateGlassDataTableAndChart` to use native Canvas API IF Chart.js is not assumed.
// —- REVISING `updateGlassDataTableAndChart` for pure Canvas —-
// This revised approach uses the Canvas API directly.
function drawChartManually() {
var canvas = document.getElementById('loadCapacityChart');
if (!canvas) return;
var ctx = canvas.getContext('2d');
if (!ctx) return;
// Clear canvas
ctx.clearRect(0, 0, canvas.width, canvas.height);
// Get data (assuming updateGlassDataTableAndChart populated chartLabels, weightData, loadData)
var chartLabels = [];
var weightData = [];
var loadData = [];
// Re-populate data for chart drawing (this should ideally be passed from the calculation function)
// For simplicity, we'll re-calculate based on current inputs, or better, fetch from a global scope if set.
// Let's assume updateGlassDataTableAndChart populates these arrays in a scope accessible here.
// A better approach is to return data from updateGlassDataTableAndChart and use it here.
// For now, let's simulate getting the data – In a real scenario, these would be populated by `updateGlassDataTableAndChart`
// and passed to `drawChartManually` or stored globally.
// This part requires `updateGlassDataTableAndChart` to store these values in global scope or return them.
// Let's simulate `updateGlassDataTableAndChart` setting these globally for this example.
if (typeof window.chartData === 'undefined') {
console.error("Chart data not prepared.");
return;
}
chartLabels = window.chartData.labels;
weightData = window.chartData.weights;
loadData = window.chartData.loads;
var numBars = chartLabels.length;
if (numBars === 0) return;
var padding = 40;
var chartAreaWidth = canvas.width – 2 * padding;
var chartAreaHeight = canvas.height – 2 * padding;
var barWidth = (chartAreaWidth / numBars) * 0.35; // 35% of segment width for bar
var barSpacing = (chartAreaWidth / numBars) * 0.65; // Remaining space for spacing
var maxWeight = Math.max.apply(null, weightData);
var maxLoad = Math.max.apply(null, loadData);
var yAxisMax = Math.max(maxWeight, maxLoad) * 1.1; // Add 10% buffer
// Y-axis (Left – Weight)
ctx.strokeStyle = 'rgba(0, 74, 153, 1)';
ctx.fillStyle = 'rgba(0, 74, 153, 1)';
ctx.lineWidth = 1;
ctx.font = '12px Segoe UI';
ctx.textAlign = 'right';
ctx.textBaseline = 'middle';
// Draw Left Y-Axis and Ticks
var yAxisLeftX = padding;
var yAxisBottomY = canvas.height – padding;
ctx.beginPath();
ctx.moveTo(yAxisLeftX, padding);
ctx.lineTo(yAxisLeftX, yAxisBottomY);
ctx.stroke();
var tickCount = 5;
for (var i = 0; i <= tickCount; i++) {
var y = yAxisBottomY – (i / tickCount) * chartAreaHeight;
var value = (i / tickCount) * yAxisMax;
ctx.fillText(value.toFixed(0), yAxisLeftX – 5, y);
ctx.beginPath();
ctx.moveTo(yAxisLeftX – 5, y);
ctx.lineTo(yAxisLeftX, y);
ctx.stroke();
}
ctx.fillText('kg/m²', yAxisLeftX – 25, padding / 2); // Axis label
// Y-axis (Right – Load)
ctx.strokeStyle = 'rgba(40, 167, 69, 1)';
ctx.fillStyle = 'rgba(40, 167, 69, 1)';
var yAxisRightX = canvas.width – padding;
ctx.beginPath();
ctx.moveTo(yAxisRightX, padding);
ctx.lineTo(yAxisRightX, yAxisBottomY);
ctx.stroke();
// No ticks for right axis to avoid clutter, just label
ctx.textAlign = 'left';
ctx.fillText('kg/m²', yAxisRightX + 15, padding / 2);
// X-axis
ctx.strokeStyle = '#333';
ctx.fillStyle = '#333';
ctx.textAlign = 'center';
ctx.textBaseline = 'top';
ctx.beginPath();
ctx.moveTo(padding, yAxisBottomY);
ctx.lineTo(canvas.width – padding, yAxisBottomY);
ctx.stroke();
// Draw Bars and Labels
for (var i = 0; i < numBars; i++) {
var x = yAxisLeftX + barSpacing / 2 + i * (barWidth + barSpacing);
var weightBarHeight = (weightData[i] / yAxisMax) * chartAreaHeight;
var loadBarHeight = (loadData[i] / yAxisMax) * chartAreaHeight;
// Draw Weight Bar (Left)
ctx.fillStyle = 'rgba(0, 74, 153, 0.6)';
ctx.fillRect(x, yAxisBottomY – weightBarHeight, barWidth, weightBarHeight);
// Draw Load Bar (Right) – slightly offset or side-by-side for clarity
var loadBarX = x + barWidth + barSpacing / 4; // Position next to weight bar
ctx.fillStyle = 'rgba(40, 167, 69, 0.6)';
ctx.fillRect(loadBarX, yAxisBottomY – loadBarHeight, barWidth, loadBarHeight);
// Draw X-axis Label (Thickness)
ctx.fillStyle = '#333';
ctx.fillText(chartLabels[i], x + barWidth / 2 + barSpacing / 8, yAxisBottomY + 10); // Centered below bars
}
}
// Modify `updateGlassDataTableAndChart` to prepare data for manual drawing
function updateGlassDataTableAndChart() {
var dataTableBody = document.getElementById('glassDataTableBody');
dataTableBody.innerHTML = ''; // Clear previous data
var baseThicknessMM = parseFloat(glassThicknessInput.value);
var baseWidthMM = parseFloat(glassWidthInput.value);
var baseHeightMM = parseFloat(glassHeightInput.value);
var baseDensity = parseFloat(glassDensityInput.value);
var baseSafetyFactor = parseFloat(safetyFactorInput.value);
var chartLabels = [];
var weightData = []; // Weight per m²
var loadData = []; // Min Safety Load per m²
var thicknessesToChart = [4, 6, 8, 10, 12, 15, 19, 25]; // Common thicknesses
for (var i = 0; i < thicknessesToChart.length; i++) {
var thickness = thicknessesToChart[i];
var thicknessM = thickness / 1000;
// Calculate for a 1m x 1m pane for table/chart consistency
var area1m2 = 1.0; // 1 m²
var weight1m2 = area1m2 * baseDensity; // Weight of 1 m² pane
var minLoad1m2 = weight1m2 * baseSafetyFactor; // Min load for 1 m² pane
chartLabels.push(thickness + ' mm');
weightData.push(weight1m2);
loadData.push(minLoad1m2);
var row = dataTableBody.insertRow();
var cellThickness = row.insertCell(0);
var cellWeight = row.insertCell(1);
var cellLoad = row.insertCell(2);
var cellMaxRecommendedLoad = row.insertCell(3);
cellThickness.textContent = thickness + ' mm';
cellWeight.textContent = weight1m2.toFixed(2);
cellLoad.textContent = minLoad1m2.toFixed(2);
cellMaxRecommendedLoad.textContent = (minLoad1m2 * 1.5).toFixed(2); // Example
}
// Store chart data for manual drawing function
window.chartData = {
labels: chartLabels,
weights: weightData,
loads: loadData
};
drawChartManually(); // Call manual drawing function
}
// Override initial call to use manual drawing
document.addEventListener('DOMContentLoaded', function() {
var inputs = [glassThicknessInput, glassWidthInput, glassHeightInput, glassDensityInput];
for (var i = 0; i < inputs.length; i++) {
inputs[i].addEventListener('input', calculateGlassLoad);
}
safetyFactorInput.addEventListener('change', calculateGlassLoad);
document.getElementById('resetButton').addEventListener('click', resetCalculator);
document.getElementById('copyButton').addEventListener('click', copyResults);
document.getElementById('calculateButton').addEventListener('click', calculateGlassLoad);
resetCalculator(); // Load with default values and perform initial calculation
});