Math & Engineering
Snow Load Calculator
Calculate the design snow load for roofs and structures based on various environmental and structural factors.
Enter values to calculate snow load
Related to Snow Load Calculator
The Snow Load Calculator determines the design snow load (pf) on roofs and structures using the following formula:
pf = pg × Ce × Ct × Is × Cs
Where:
- pf = Design snow load
- pg = Ground snow load
- Ce = Exposure factor
- Ct = Thermal factor
- Is = Importance factor
- Cs = Slope factor
The calculator takes into account various factors that affect snow accumulation on structures:
Key Factors
- Ground Snow Load (pg): The weight of snow on the ground in kN/m²
- Exposure Factor (Ce): Accounts for wind exposure effects on snow accumulation
- Thermal Factor (Ct): Considers heat loss through the roof affecting snow melting
- Importance Factor (Is): Reflects the building's importance and occupancy
- Slope Factor (Cs): Accounts for snow sliding off sloped roofs
The calculator provides two key results that are essential for structural design and building safety:
Design Snow Load (pf)
This is the final calculated snow load that the structure must be designed to support, measured in kN/m². This value represents the maximum expected snow load on the roof, taking into account all environmental and structural factors. Engineers use this value to design roof structures and support systems.
Slope Factor (Cs)
This factor indicates how much snow is likely to remain on the roof based on its slope. A value of 1.0 means all snow stays on the roof (typical for flat roofs), while lower values indicate that some snow will slide off. For slopes over 70 degrees, Cs becomes 0, indicating no snow accumulation.
1. What is ground snow load and how is it determined?
Ground snow load is the weight of snow on the ground, typically measured in kilonewtons per square meter (kN/m²). It is determined based on historical weather data and local building codes. Local authorities usually provide ground snow load values for different regions based on statistical analysis of snowfall records.
2. How does roof slope affect snow load?
Roof slope affects snow load through the slope factor (Cs). For slopes up to 30 degrees, all snow typically stays on the roof (Cs = 1.0). Between 30 and 70 degrees, snow gradually slides off, reducing the effective load. Above 70 degrees, no significant snow accumulation is expected (Cs = 0).
3. Why is the exposure factor important?
The exposure factor (Ce) accounts for how wind affects snow accumulation on roofs. Sheltered areas (Ce = 0.8) tend to accumulate more snow, while exposed areas (Ce = 1.2) may have less accumulation due to wind effects. Normal exposure (Ce = 1.0) represents typical conditions.
4. What determines a building's importance factor?
The importance factor (Is) reflects the building's use and the consequences of its failure. Critical facilities like hospitals have higher factors (Is = 1.25), while low-risk structures like storage buildings may have lower factors (Is = 0.8). Normal occupancy buildings use Is = 1.0.
5. What is the scientific source for this calculator?
This calculator is based on the ASCE 7 (American Society of Civil Engineers) standard "Minimum Design Loads and Associated Criteria for Buildings and Other Structures," specifically Chapter 7 on Snow Loads. The calculations follow the methodology outlined in ASCE 7-16, which is widely accepted in structural engineering practice. The formulas and factors used are also consistent with international building codes such as the International Building Code (IBC) and European standard Eurocode 1: Actions on structures - Part 1-3: General actions - Snow loads (EN 1991-1-3).