Site Quantities — How Calculations Work
Overview
This page explains the calculation logic behind the Site Chemical Quantity Aggregation feature — how Tellus converts your inventory into site-level chemical totals and determines threshold compliance.
Unit Conversions
All quantities are normalized to pounds (lbs) for weight and gallons (gal) for volume using standard conversion factors:
Weight Conversions (to pounds)
| Unit | Conversion Factor |
|---|---|
| lbs | 1.0 |
| oz | 0.0625 |
| kg | 2.2046 |
| g | 0.0022 |
| mg | 0.0000022 |
| ton | 2,000.0 |
Volume Conversions (to gallons)
| Unit | Conversion Factor |
|---|---|
| gal | 1.0 |
| L (liter) | 0.2642 |
| qt (quart) | 0.25 |
| pt (pint) | 0.125 |
| fl oz | 0.0078 |
| mL | 0.000264 |
| cu ft | 7.4805 |
Weight ↔ Volume Conversion
To convert between weight and volume, Tellus uses chemical-specific densities (in lbs/gal). When no density is available for a specific chemical, water density (8.34 lbs/gal) is used as the default.
Quantity Calculation Per Chemical Component
For each inventory item, the calculation is:
Total item quantity = container size × number of containers
Chemical quantity = total item quantity × conversion factor × concentration percentage
Concentration is taken from the SDS composition data — the percentage of each chemical in the product. If no concentration is available, the chemical is treated as 100% of the product.
Example: You have 3 bottles of a cleaner, each 1 gallon, and the SDS shows it contains 15% acetone:
- Total item quantity = 1 gal × 3 = 3 gallons
- Acetone contribution = 3 gal × 0.15 = 0.45 gallons
- Acetone in pounds = 0.45 gal × 6.56 lbs/gal (acetone density) = 2.95 lbs
Tier II Thresholds
EPA EPCRA Section 312 requires facilities to file annual Tier II reports for hazardous chemicals stored above these thresholds:
| Chemical Type | Threshold |
|---|---|
| General hazardous chemicals | 10,000 lbs |
| Extremely Hazardous Substances (EHS) | 500 lbs |
In the UI, a green checkmark means the chemical is below the threshold. A red indicator means it exceeds — and the chemical should be included in your Tier II report.
Fire Code Thresholds
Based on the International Fire Code (IFC) Table 5003.1.1(1) — Maximum Allowable Quantities per control area for indoor storage:
Flammable & Combustible Liquids
| Class | Description | Max Qty (gallons) |
|---|---|---|
| IA | Flash point < 73°F, boiling point < 100°F | 30 |
| IB | Flash point < 73°F, boiling point ≥ 100°F | 120 |
| IC | Flash point 73–100°F | 120 |
| II (Combustible) | Flash point 100–140°F | 120 |
| IIIA (Combustible) | Flash point 140–200°F | 330 |
| IIIB (Combustible) | Flash point ≥ 200°F | 13,200 |
Oxidizers
| Class | Max Qty (lbs) |
|---|---|
| 1 | 4,000 |
| 2 | 250 |
| 3 | 10 |
| 4 | 1 (any amount requires a permit) |
How Fire Code Class Is Determined
Tellus maps GHS hazard classifications from the SDS to International Fire Code categories:
| GHS Hazard Class | GHS Category | Fire Code Category | Fire Code Class |
|---|---|---|---|
| Flammable liquid | Category 1 | Flammable Liquid | IA |
| Flammable liquid | Category 2 | Flammable Liquid | IB |
| Flammable liquid | Category 3 | Flammable Liquid | IC |
| Flammable liquid | Category 4 | Combustible Liquid | II |
| Oxidizer | Category 1 | Oxidizer | 4 |
| Oxidizer | Category 2 | Oxidizer | 3 |
| Oxidizer | Category 3 | Oxidizer | 2 |
Hazard Summary Aggregation
The Hazard Summary tab groups all chemicals by their fire code classification and totals the quantities. The % of Limit is calculated as:
% of Limit = (total quantity for this hazard group ÷ fire permit limit) × 100
This tells you at a glance how close each hazard category is to the fire code maximum — 50% means you're using half your allowable capacity, 100% means you've reached the limit.