ICC - International Code Council
 
Cart                                                                   
Skip to main content
 
Membership

Your ICC Account

Email:
Password:
Bookmark and Share
ICC-ES

Codes & Standards Discussion Forum 

Welcome to the ICC Codes & Standards Discussion Forum

The Code Council has revisited how best to provide an online, professional Discussion Forum and area within the website that has a sense of community – where Members and nonmembers can provide input and exchange ideas with their peers in the industry. The new Codes & Standards Discussion Forum does just that, as it allows Registered Website Users and ICC Members to discuss the I-Codes in an online community.

Members Area Codes & Standards Discussion Forum

Note to Nonmembers: If you join the ICC you can have access to important building safety information!

Members Area Codes & Standards Discussion Forum

As an ICC Member, you have access to the Members Area of the Codes & Standards Discussion Forum. Follow the link to discuss the Membership Councils and other benefits of being an ICC Member.


22 post(s) First 1 2 > Last
Search 
Roof scuppers and overflow drains.
This forum is under moderation. Your reply will appear when it is approved.
Re: Roof scuppers and overflow drains. By  permitguy

Posts: 0

3/10/2006 1:44:00 PM

2003 IBC 1611

Also see 2003 IPC 1106 and 1107.


   

Re: Roof scuppers and overflow drains. By  maniac

Posts: 0

3/10/2006 2:28:00 PM

2000 or 2003


   

Re: Roof scuppers and overflow drains. By  simplemind

Posts: 0

3/14/2006 2:54:00 PM

2003


   

Re: Roof scuppers and overflow drains. By  maniac

Posts: 0

3/16/2006 10:20:00 AM

ROOF DRAINAGE . . . . . . . . . . . . . . . . . . . . . . . 1503.4

1503.4 Roof drainage. Design and installation of roof drainage systems shall comply with the International Plumbing Code.

TABLE 1507.3.7
drainage by a minimum of 1/8-inch

1507.11.1 Slope. Modified bitumen membrane roofs shall
have a design slope of a minimum of one-fourth unit vertical
in 12 units horizontal (2-percent slope) for drainage.

1507.10.1 Slope. Built-up roofs shall have a design slope of
a minimum of one-fourth unit vertical in 12 units horizontal
(2-percent slope) for drainage, except for coal-tar built-up
roofs that shall have a design slope of a minimum one-eighth
unit vertical in 12 units horizontal (1-percent slope).

SCUPPER. See Section 1502.1. International Building Code
Section 1107 of the International Plumbing Code (IPC) and Section 8.3 of ASCE

TABLE 1604.3
deflections do not ensure against ponding. Roofs that do not have sufficient slope or camber to assure adequate drainage shall be investigated for ponding. See Section 1611 for rain and ponding requirements and Section 1503.4 for roof drainage requirements.

SECTION 1611RAIN LOADS
1611.1 Design rain loads. Each portion of a roof shall be designed to sustain the load of rainwater that will accumulate on it if the primary drainage system for that portion is blocked plus the uniform load caused by water that rises above the inlet of the secondary drainage system at its design flow.

2303.4.1 Truss design drawings.
The analysis shall also show that the roof drainage system and the foregoing systems or equipment will not be adversely affected or, as an alternate, such systems shall be designed to accommodate the differential shrinkage or movements.


   

Re: Roof scuppers and overflow drains. By  simplemind

Posts: 0

3/16/2006 4:36:00 PM

Thanks, Maniac!!! Great code citation. The one thing I am unsure of right now is how high the overflow drain should be placed relative to the roof finish. I knew it before to be at 2". Somehow I could not find that in the current codes. Do you know the codes section for that, too?


   

Re: Roof scuppers and overflow drains. By  peach!!

Posts: 0

3/16/2006 4:58:00 PM

I couldn''t find it either.. but the roof design is going to drive the drainage train..


   

Re: Roof scuppers and overflow drains. By  maniac

Posts: 0

3/16/2006 5:08:00 PM

Your answer

In latin
Circulus in Probando

In English
Circular logic

International Building Code 1503.4 Roof drainage. Design and installation of roof drainage systems shall comply with the International Plumbing Code.


2003 INTERNATIONAL PLUMBING CODE
1106.5 Parapet wall scupper location. Parapet wall roof drainage scupper and overflow scupper location shall comply with the requirements of the International Building Code.


2003 INTERNATIONAL PLUMBING CODE Also states
SECTION 1107
SECONDARY (EMERGENCY) ROOF DRAINS
1107.1 Secondary drainage required. Secondary (emergency) roof drains or scuppers shall be provided where the roof perimeter construction extends above the roof in such a manner that water will be entrapped if the primary drains allow buildup for any reason.

1107.3 Sizing of secondary drains. Secondary (emergency) roof drain systems shall be sized in accordance with Section 1106 based on the rainfall rate for which the primary system is sized in Tables 1106.2, 1106.3 and 1106.6. Scuppers shall be sized to prevent the depth of pondingwater 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. The flow through the primary system shall not be considered when sizing the secondary roof drain system.
1107.2 Separate systems required. Secondary roof drain systems shall have the end point of discharge separate from the primary system. Discharge shall be above grade, in a location which would normally be observed by the building occupants or maintenance personnel.


There isn''t a dimension.


   

Re: Roof scuppers and overflow drains. By  peach!!

Posts: 0

3/17/2006 11:43:00 AM

way back (my very first reserve annual training), we were in key west helping the county emergency managers update their hurricane evacuation plans... my job was to evaluate potential shelters, one of which was an almost new bank... went over there (5,000 sf 2 story square building with not very many windows.. promising)... went on the roof - 4'' parapet.. not only were there no scuppers, the only way to get water off the roof was thru the plumbing stacks...


didn''t approve it as a shelter..


   

Re: Roof scuppers and overflow drains. By  GlassArch

Posts: 0

3/30/2006 12:01:00 PM

The IPC says: Scuppers shall be sized to prevent the depth of ponding water from exceeding that for which the roof was designed...

The 2000 UPC gives a scupper width based on head of water. If you know how much water your roof can hold, you can put this "head" of water into Appendix D, table D-2. This will give the width of the scupper.

Where does the IPC give a method of sizing the scupper?


   

Re: Roof scuppers and overflow drains. By  Paul Sweet

Posts: 0

3/30/2006 12:59:00 PM

A scupper is basically a pipe of negligible length, so you could use IPC Table 1106.3. I would size the overflow for a 5-minute intensity in a 100 year storm (10"/hr. for Richmond, vs.3 1/4"/hr. for roof drain sizing). The bottom of the overflow should be 4" or less above the roof (based on 20 PSF design load).


   

Re: Roof scuppers and overflow drains. By  GlassArch

Posts: 0

3/30/2006 1:52:00 PM

There is too large of a difference between the UPC, which specifies an actual method of sizing a scupper and the IPC which does not.

The local bldg dept gave us 6" rain per hour. Largest roof drain area is 20,000 SF = 1250 gpm. Structure can only take 4" head of water. From the UPC this is equal to a 60" wide scupper (4"x60" = 240si), bottom located right on the deck. Using IPC 1106.3: 6"/hr 20,000 SF is 12" pipe (113si) = 28-1/4" wide

You do not get credit for a head of water higher than the structure can carry. Thus the 4" head. UPC mandates actual height twice the head. So scupper becomes 8"x60" (or two 8"x30").


   

Re: Roof scuppers and overflow drains. By  cohare

Posts: 0

5/17/2006 6:33:00 AM

I have also been looking for any part of the code that specifically says the overflow drain should be placed 2" higher than the roof finish. I have found this 2 inches mentioned in several construction books- but I can not find it mentioned in the BOCA code or the IBC. Does anyone know if this specific measuremnet is true anymore or if it is now only required to locate the scuppers in such a ways as to "prevent the depth of pondingwater from exceeding that for which the roof was designed"?
Our contractor keeps insisting that the 2" is code - howver he is unablre to produce the specific section that says this.
any help would be great! thanks!


   

Re: Roof scuppers and overflow drains. By  maniac

Posts: 0

5/17/2006 2:58:00 PM

97UBC (CBC2001)1506.3 Overflow Drains and Scuppers. Where roof drains are required, overflow drains having the same size as the roof drains
shall be installed with the inlet flow line located 2 inches above the low point of the roof, or overflow scuppers having three times the size of the roof drains and having a minimum opening
height of 4 inches may be installed in the adjacent parapet walls with the inlet flow line located 2 inches above the low point of the adjacent roof.

THE IBC HAS RESORTED TO A FORMULA
SECTION 1611
RAIN LOADS
1611.1 Design rain loads. Each portion of a roof shall be designed to sustain the load of rainwater that will accumulate on it if the primary drainage system for that portion is blocked plus the uniform load caused by water that rises above the inlet of the secondary drainage system at its design flow.
R= 5.2 (ds + dh) (Equation 16-37)
For SI: R = 0.0098 (ds + dh)
where:
dh = Additional depth of water on the undeflected roof
above the inlet of secondary drainage system at its design
flow (i.e., the hydraulic head), in inches (mm).
ds = Depth ofwater on the undeflected roof up to the inlet of
secondary drainage system when the primary drainage
system is blocked (i.e., the static head), in inches.
R = Rain load on the undeflected roof, in psf. When the phrase ?undeflected roof? is used, deflections from loads (including dead loads) shall not be considered when determining the amount of rain on the roof.
2003 INTERNATIONAL BUILDING CODE?


   

Re: Roof scuppers and overflow drains. By  maniac

Posts: 0

5/17/2006 2:58:00 PM

97UBC (CBC2001)1506.3 Overflow Drains and Scuppers. Where roof drains are required, overflow drains having the same size as the roof drains
shall be installed with the inlet flow line located 2 inches above the low point of the roof, or overflow scuppers having three times the size of the roof drains and having a minimum opening
height of 4 inches may be installed in the adjacent parapet walls with the inlet flow line located 2 inches above the low point of the adjacent roof.

THE IBC HAS RESORTED TO A FORMULA
SECTION 1611
RAIN LOADS
1611.1 Design rain loads. Each portion of a roof shall be designed to sustain the load of rainwater that will accumulate on it if the primary drainage system for that portion is blocked plus the uniform load caused by water that rises above the inlet of the secondary drainage system at its design flow.
R= 5.2 (ds + dh) (Equation 16-37)
For SI: R = 0.0098 (ds + dh)
where:
dh = Additional depth of water on the undeflected roof
above the inlet of secondary drainage system at its design
flow (i.e., the hydraulic head), in inches (mm).
ds = Depth ofwater on the undeflected roof up to the inlet of
secondary drainage system when the primary drainage
system is blocked (i.e., the static head), in inches.
R = Rain load on the undeflected roof, in psf. When the phrase ?undeflected roof? is used, deflections from loads (including dead loads) shall not be considered when determining the amount of rain on the roof.
2003 INTERNATIONAL BUILDING CODE?


   

Re: Roof scuppers and overflow drains. By  david yount

Posts: 0

5/18/2006 5:25:00 AM

Excellent posts Maniac!!!!! Best part of this site is the ability to know and learn. THanks


   

22 post(s) First 1 2 > Last
2015 I-Codes
2015 I-Codes