• ROOFING APPLICATION STANDARD (RAS) No.128
    STANDARD PROCEDURE FOR DETERMINING APPLICABLE WIND DESIGN
    PRESSURES FOR LOW SLOPE ROOF

    1.Scope

    1. 1.1This roofing application standard has been developed to provide a responsive method of complying with the requirements of Chapters 15 & 16 (High-Velocity Hurricane Zones) of the Florida Building Code, Building. Compliance with the requirements and procedures herein specified, where the pressures (Pasd) have been determined based on Table 1 or 2, of this standard, as applicable, do not require additional signed and sealed engineering design calculations. All other calculations must be prepared, signed and sealed by a professional engineer or registered architect.

    2.Definitions

    1. 2.1For definitions of terms used in this application standard, refer to ASTM D1079 and the Florida Building Code, Building.

    3.Applicability

    1. 3.1This application standard applies to:

      1. a.exposure C and D category buildings; and

      2. b.building heights of less than or equal to 40 feet; and

      3. c.roof incline (pitch) is not greater than 1/2 in.:12 in.

      4. d.risk category II buildings.

    2. 3.2Using Table 1 or 2 below, as applicable, determine the minimum design pressure for each respective roof area, which corresponds to the applicable roof height range.

    3. 3.3Referencing the selected Roof Assembly Product Approval, check that the listed maximum allowable design pressure for the particular approved system meets or exceeds those listed in Table 1 or Table 2 above, as applicable.

    TABLE 1 — RISK CATEGORY II EXPOSURE CATEGORY “C”1, 2 MINIMUM DESIGN WIND UPLIFT PRESSURES, IN PSF FOR FIELD [Pasd(1)], PERIMETER [Pasd(2)] AND CORNER [Pasd(3)] AREAS OF ROOFS FOR EXPOSURE “C” BUILDINGS

    Roof mean height (below)Pasd(1) (Field)Pasd(2) (Perimeter)Pasd(3) (Corners)
    20-42.8-71.7-108.0
    25-44.8-75.1-113.0
    30-46.4-77.8-117.2
    35-48.1-80.6-121.3
    40-49.4-82.9-124.7
    1. 1 Calculated in accordance with ASCE 7.

    2. 2 Pasd = 0.6Pult

    TABLE 2 — RISK CATEGORY II EXPOSURE CATEGORY “D”1, 2 MINIMUM DESIGN WIND UPLIFT PRESSURES, IN PSF FOR FIELD [Pasd(1)], PERIMETER [Pasd(2)] AND CORNER [Pasd(3)] AREAS OF ROOFS FOR EXPOSURE “D” BUILDINGS

    Roof mean height (below)Pasd(1) (Field)Pasd(2) (Perimeter)Pasd(3) (Corners)
    20-51.4-86.2-129.7
    25-53.4-89.5-134.7
    30-55.0-92.3-138.9
    35-56.4-94.5-142.3
    40-57.7-96.8-145.6
    1. 1 Calculated in accordance with ASCE 7.

    2. 2 Pasd = 0.6Pult

FEEDBACK LIVE CHAT