Convertidor Universal Pro

What is a Snow Load Calculator?

A Snow Load Calculator estimates the snow load on a roof based on ground snow load, snow type, exposure, thermal, importance factors, and roof slope, following ASCE 7-16 standards. Snow load is critical for designing safe roofs in snowy regions.

This calculator accounts for flat and sloped roofs, including rain-on-snow surcharges for low slopes. It is ideal for architects, engineers, and builders planning structures in snow-prone areas.

Snow Load Calculation Details

The snow load is calculated using the ASCE 7-16 standard for flat roof snow load: p_f = 0.7 * C_e * C_t * I_s * p_g [Ref: skyciv.com].

C_e: Exposure factor (user-selected: 0.7 for fully exposed, 0.9 for partially exposed, 1.0 for sheltered, 1.2 for obstructed) [Ref: buildingsguide.com].

C_t: Thermal factor (1.0 for warm roofs, typical for most buildings; 1.1 for cold roofs; 1.2 for unheated structures) [Ref: skyciv.com].

I_s: Importance factor (0.8 for low risk, 1.0 for standard, 1.1 for high occupancy, 1.2 for critical facilities) [Ref: structed.org].

p_g: Ground snow load (user-entered, e.g., 25 psf) [Ref: skyciv.com].

Slope Adjustment: C_s = 1.0 for α ≤ 15°, C_s = 0 for α > 60°, or C_s = (60 - α)/45 for 15° < α ≤ 60° [Ref: skyciv.com].

Rain-on-Snow Surcharge: 5 psf if p_g ≤ 20 psf and roof slope < 5° [Ref: buildingsguide.com].

Snow Density (for reference, not direct calculation): Fresh: ~7 lb/ft³, Wet: ~21 lb/ft³, Wind-packed: ~23 lb/ft³ [Ref: inchcalculator.com].

Output: Flat roof snow load (p_f), sloped roof snow load (p_f * C_s), and rain-on-snow surcharge.

Example Output: For ground snow load=25 psf, snow type=wet, exposure factor=0.9, thermal factor=1.0, importance factor=1.0, roof slope=10°, unit=feet: Flat Roof Snow Load: 15.75 psf, Sloped Roof Snow Load: 15.75 psf, Rain-on-Snow Surcharge: 0 psf (since slope ≥ 5°).

Snow Load by Roof Type

How to Use the Snow Load Calculator

1. Ground Snow Load: Enter the ground snow load (psf or kN/m²) for your location (e.g., from ASCE 7-16 or local codes).
2. Snow Type: Select the snow type (fresh, wet, wind-packed).
3. Exposure Factor: Choose the exposure factor based on site conditions (e.g., fully exposed, sheltered).
4. Thermal Factor: Select the thermal factor based on roof insulation (e.g., warm or cold roof).
5. Importance Factor: Choose the importance factor based on building use (e.g., residential, critical facility).
6. Roof Slope: Enter the roof slope angle (degrees).
7. Unit: Choose the unit of measurement (feet or meters).
8. Calculate: Determine the flat roof snow load, sloped roof snow load, and any rain-on-snow surcharge.

Snow Load by Roof Slope (psf)

Based on 25 psf ground snow load, wet snow, partially exposed, warm roof

Additional Information for Snow Load Planning

Design Considerations: Ensure roof design accounts for snow load, wind, and other forces. Consult ASCE 7-16 or local codes for accurate ground snow load data.

Location Data: Ground snow load varies by region. Use tools like Dlubal Geo-Zone Tool for precise values by ZIP code.

Safety Tips: Install snow guards on sloped roofs to prevent sudden snow slides. Consult a structural engineer for complex designs.

Frequently Asked Questions (FAQ)

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