Oklahoma Administrative Code
Title 748 - Oklahoma Uniform Building Code Commission
Chapter 20 - Adopted Codes
Subchapter 16 - IPC[®] 2018
Section 748:20-16-16 - IPC[®] 2018 Chapter 11 Storm Drainage

Universal Citation: OK Admin Code 748:20-16-16

Current through Vol. 42, No. 1, September 16, 2024

Chapter 11 of the Oklahoma adopted IPC® 2018 is adopted with the following modifications:

(1) Section 1101.7 Roof design. This section has been modified to change the section number for the requirement to accommodate the design rate for secondary roof drainage from Section 1106 to Section 1108. This section has been modified to read: 1101.7 Roof design. Roofs shall be designed for the maximum possible depth of water that will pond thereon as determined by the relative levels of roof deck and overflow weirs, scuppers, edges or serviceable drains in combination with the deflected structural elements. In determining the maximum possible depth of water, all primary roof drainage means shall be assumed to be blocked. The maximum possible depth of water on the roof shall include the height of the water required above the inlet of the secondary roof drainage means to achieve the required flow rate of secondary drainage means to accommodate the design rainfall rate as required by Section 1108.

(2) Section 1101.9 Backwater valves. This section has been modified to address errata published by the ICC® to correct a specified section reference from "715" to "714". This section has been modified to read: 1101.9 Backwater valves. Storm drainage systems shall be provided with backwater valves as required for sanitary drainage systems in accordance with Section 714.

(3) Table 1108.1 Size of Secondary Scuppers for a 10.2-inch Per Hour Rate of Rainfall. This table has been added to provide sizing guidance for secondary scuppers for a 10.2-inch per hour rate of rainfall. The table has been added to read: Table 1108.1 Size of Secondary Scuppers for a 10.2-inch Per Hour Rate of Rainfall. The table contains 5 rows and 2 columns. The second column contains seven sub-columns. The table is described

(A) Row 1 is the header row and contains the following headings:
(i) Row 1, column 1, is entitled "Head in inches."

(ii) Row 1, column 2 is entitled "Horizontally Projected Roof areas (Square Feet) Length of Weir in inches."
(I) Row 1, column 2, subcolumn 1 is entitled "4."

(II) Row 1, column 2, subcolumn 2 is entitled "6."

(III) Row 1, column 2, subcolumn 3 is entitled "8."

(IV) Row 1, column 2, subcolumn 4 is entitled "12."

(V) Row 1, column 2, subcolumn 5 is entitled "16."

(VI) Row 1, column 2, subcolumn 6 is entitled "20."

(VII) Row 1, column 2 subcolumn 7 is entitled "24."

(B) Row 2 contains the following information in both of the columns listed in header row 1:
(i) Row 2, column 1 lists the Head in inches number "1."

(ii) Row 2, column 2 lists the following in each of the seven subcolumns:
(I) Row 2, column 2, subcolumn 1 entitled "4" lists "112."

(II) Row 2, column 2, subcolumn 2 entitled "6" lists "169."

(III) Row 2, column 2, subcolumn 3 entitled "8" lists "226."

(IV) Row 2, column 2, subcolumn 4 entitled "12" lists "339."

(V) Row 2, column 2, subcolumn 5 entitled "16" lists "452."

(VI) Row 2, column 2 subcolumn 6 entitled "20" lists "565."

(VII) Row 2, column 2, subcolumn 7 entitled "24" lists "678."

(C) Row 3 contains the following information in both of the columns listed in header row 1:
(i) Row 3, column 1 lists the Head in inches number "2."

(ii) Row 3, column 2 lists the following in each of the seven subcolumns:
(I) Row 3, column 2, subcolumn 1 entitled "4" lists "314."

(II) Row 3, column 2, subcolumn 2 entitled "6" lists "471."

(III) Row 3, column 2, subcolumn 3 entitled "8" lists "628."

(IV) Row 3, column 2, subcolumn 4 entitled "12" lists "942."

(V) Row 3, column 2, subcolumn 5 entitled "16" lists "1256."

(VI) Row 3, column 2 subcolumn 6 entitled "20"lists "1571."

(VII) Row 3, column 2, subcolumn 7 entitled "24" lists "1885."

(D) Row 4 contains the following information in both of the columns listed in header row 1:
(i) Row 4, column 1 lists the Head in inches number "3."

(ii) Row 4, column 2 lists the following in each of the seven subcolumns:
(I) Row 4, column 2, subcolumn 1 entitled "4" lists "565."

(II) Row 4, column 2, subcolumn 2 entitled "6" lists "848."

(III) Row 4, column 2, subcolumn 3 entitled "8" lists "1130."

(IV) Row 4, column 2, subcolumn 4 entitled "12" lists "1696."

(V) Row 4, column 2, subcolumn 5 entitled "16" lists "2262."

(VI) Row 4, column 2 subcolumn 6 entitled "20" lists "2828."

(VII) Row 4, column 2, subcolumn 7 entitled "24" lists "3393."

(E) Row 5 contains the following information in both of the columns listed in header row 1:
(i) Row 5, column 1 lists the Head in inches number "4."

(ii) Row 5, column 2 lists the following in each of the seven subcolumns:
(I) Row 5, column 2, subcolumn 1 entitled "4" lists "879."

(II) Row 5, column 2, subcolumn 2 entitled "6" lists "1319."

(III) Row 5, column 2, subcolumn 3 entitled "8" lists "1759."

(VI) Row 5, column 2, subcolumn 4 entitled "12" lists "2637."

(V) Row 5, column 2, subcolumn 5 entitled "16" lists "3519."

(VI) Row 5, column 2 subcolumn 6 entitled "20" lists "4399."

(VII) Row 2, column 2, subcolumn 7 entitled "24" lists "5279."

(F) Beneath the table the following should be added: For SI: 1 inch equals 25.4 mm. Notes:
(i) To adjust this table for other than a 10.2-inch design rain fall rate multiply the square footage on the table by 10.2 then divide by the design rainfall rate.

(ii) This table does not apply to scuppers with a vertical opening height that is less than the head height. Example: For 4 inches of design rainfall rate, a 4-inch long scupper with a 1-inch head would accommodate 286 square feet. (112 times 10.2) divided by 4 equals 286.

(4) Section 1108.3 Sizing of secondary drains. This section has been modified to include the use of scuppers or increase the sizing of secondary drains to accommodate rainfalls of 10.2 inches per hour and includes minimum design loads. This section has been modified to read: 1108.3 Sizing of secondary drains. Secondary (emergency) roof drain systems or scuppers shall be sized in accordance with Section 1108 based on a rainfall rate of 10.2 inches per hour. In sizing secondary roof drain systems using Tables 1106.2, 1106.3 and 1106.6, the Horizontally Projected Roof Area shall be determined by dividing the Horizontally Projected Roof Area for 1-inch rain fall per hour rate by 10.2 inches per hour. Scuppers shall be sized to prevent the depth of ponding water from exceeding that for which the roof was designed as determined by Section 1101.7. Scuppers shall not have an opening dimension of less than 4 inches (102 mm). The flow through the primary system shall not be considered when sizing the secondary roof drain system or scuppers. Scuppers shall be sized in accordance with Table 1108.1 or by other national methods using the head height of water and flow rate of the scupper.

Disclaimer: These regulations may not be the most recent version. Oklahoma may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
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