This chapter shall govern the materials,
design, and installation of storm water drainage
systems.
Roofs, paved areas, yards, courts,
courtyards, vent shafts, light wells, or similar areas having
rainwater, shall be drained into a separate storm sewer
system, or into a combined sewer system where a separate
storm sewer system is not available, or to some other place
of disposal satisfactory to the Authority Having Jurisdiction.
In the case of one- and two-family dwellings, storm
water shall be permitted to be discharged on flat areas, such
as streets or lawns, so long as the storm water shall flow
away from the building and away from adjoining property,
and shall not create a nuisance.
Storm water shall not be drained into sewers
intended for sanitary drainage.
Pipe, tube, and fittings conveying
rainwater shall be of such materials and design as to
perform their intended function to the satisfaction of the
Authority Having Jurisdiction. Conductors within a vent or
shaft shall be of cast-iron, galvanized steel, wrought iron,
copper, copper alloy, lead, Schedule 40 ABS DWV,
Schedule 40 PVC DWV, stainless steel 304 or 316L [stainless
steel 304 pipe and fittings shall not be installed underground
and shall be kept not less than 6 inches (152 mm)
aboveground], or other approved materials, and changes in
direction shall be in accordance with the requirements of
Section 706.0. ABS and PVC DWV piping installations
shall be installed in accordance with this code, and the
California Building Code. Except for individual single-family
dwelling units, materials exposed within ducts or plenums shall have a flame-spread index of not more than
25 and a smoke developed index of not more than 50,
where tested in accordance with ASTM E84 or UL 723.
[HCD 1 & HCD 2] ABS or PVC installations are limited to not more than two stories of areas of residential accommodation.
[OSHPD 1, 2, 3, & 4] ABS and PVC installations are not allowed.
[HCD 1 & HCD 2] ABS or PVC installations are limited to not more than two stories of areas of residential accommodation.
[OSHPD 1, 2, 3, & 4] ABS and PVC installations are not allowed.
Joints and
connections in copper and copper alloy pipe and tube
shall be installed in accordance with Section 705.3 .
Conductors installed aboveground
in buildings shall be in accordance with the
applicable standards referenced in Table 701.2 for
aboveground drain, waste, and vent pipe. Conductors
installed above ground level shall be of seamless copper
water tube, Type K, L, or M; Schedule 40 copper pipe
or Schedule 40 copper alloy pipe; Type DWV copper
drainage tube; service weight cast-iron soil pipe or
hubless cast-iron soil pipe; standard weight galvanized steel pipe; stainless steel 304 or 316L [stainless steel 304 pipe and fittings shall not be installed underground
and shall be kept not less than 6 inches (152 mm)
aboveground]; or Schedule 40 ABS or Schedule 40
PVC plastic pipe.
ABS or PVC installations are
limited to not more than two stories of areas of
residential accommodation.
ABS and PVC
installations are not allowed.
Leaders installed outside shall be in accordance with the applicable standards referenced in
Table 701.2 for aboveground drain, waste, and vent
pipe; aluminum sheet metal; galvanized steel sheet
metal; or copper sheet metaL
Underground building storm drains shall comply with
the applicable standards referenced in Table 701.2 for
underground drain, waste, and vent pipe.
Building storm
sewers shall comply with the applicable standards
referenced in Table 701.2 for building sewer pipe.
Subsoil drains shall be open
jointed, perforated, or both and constructed of materials
in accordance with Table 1101.4.6.
| MATERIAL | REFERENCED STANDARD(S) |
| PE | ASTM F405 |
| PVC | ASTM D2729 |
| Vitrified Clay (Extra strength) | ASTM C4, ASTM C700 |
Expansion joints or
sleeves shall be provided where warranted by temperature
variations or physical conditions.
Subsoil drains shall be provided
around the perimeter of buildings having basements,
cellars, crawl spaces, or floors below grade. Such subsoil
drains shall be permitted to be positioned inside or outside
of the footing. shall be of perforated or open-jointed
approved drain tile or pipe, not less than 3 inches (80 mm)
in diameter, and shall be laid in gravel, slag, crushed rock.
approved ¾ of an inch (19.1 mm) crushed, recycled glass
aggregate, or other approved porous material with not less
than 4 inches (102 mm) surrounding the pipe. Filter media
shall be provided for exterior subsoil piping.
Exception: [HCD 1 & HCD 2] Subsoil drains are mandatory only when required by the Authority Having Jurisdiction due to geological conditions.
Exception: [HCD 1 & HCD 2] Subsoil drains are mandatory only when required by the Authority Having Jurisdiction due to geological conditions.
Subsoil drains shall be piped to a
storm drain, to an approved water course, to the front street curb or gutter, to an alley, or the discharge from
the subsoil drains shall be conveyed to the alley by a
concrete gutter. Where a continuously flowing spring
or groundwater is encountered, subsoil drains shall be
piped to a storm drain or an approved water course.
Where it is not possible to convey the
drainage by gravity, subsoil drains shall discharge to an
accessible sump provided with an approved automatic
electric pump. The sump shall be not less than 15
inches (381 mm) in diameter, 18 inches (457 mm) in
depth, and provided with a fitted cover. The sump
pump shall have an adequate capacity to discharge
water coming into the sump as it accumulates to the
required discharge point, and the capacity of the pump
shall be not less than 15 gallons per minute (gpm) (0.95
L/s). The discharge piping from the sump pump shall
be not less than ½ inches (40 mm) in diameter and
have a union or other approved quick-disconnect
assembly to make the pump accessible for servicing.
For separate dwellings not
serving continuously flowing springs or groundwater,
the sump discharge pipe shall be permitted to discharge
onto a concrete splash block with a minimum length of
24 inches (610 mm). This pipe shall be within 4 inches
(102 mm) of the splash block and positioned to direct
the flow parallel to the recessed line of the splash
block.
Subsoil drains subject to
backflow where discharging into a storm drain shall be
provided with a backwater valve in the drain line so
located as to be accessible for inspection and maintenance.
Nothing in Section 1101.6 shall
prevent drains that serve either subsoil drains or
areaways of a detached building from discharging to a
properly graded open area, provided that:
- They do not serve continuously flowing springs or groundwater
- The point of discharge is not less than 10 feet (3048 mm) from a property line
- It is impracticable to discharge such drains to a storm drain, to an approved water course, to the front street curb or gutter, or to an alley.
Building subdrains located
below the public sewer level shall discharge into a sump or
receiving tank, the contents of which shall be automatically
lifted and discharged into the drainage system as required
for building sumps.
Open subsurface space adjacent
to a building, serving as an entrance to the basement or
cellar of a building, shall be provided with a drain or drains.
Such areaway drains shall be not less than 2 inches (50
mm) in diameter for areaways at a maximum of 100 square
feet (9.29 m2) in area, and shall be discharged in the manner
provided for subsoil drains not serving continuously
flowing springs or groundwater (see Section 1101.6.1). Areaways in excess of 100 square feet (9.29 m2) shall not
drain into subsoil drains. Areaway drains for areaways
exceeding 100 square feet (9.29 m2) shall be sized in accordance
with Table 1101.8.
For SI units: 1 inch = 25 mm, 1 gallon per minute = 0.06 L/s, 1/8 inch per foot = 10.4 mm/m, 1 inch per hour = 25.4 mm/h, 1 square foot = 0.0929 m2
Notes:
1 The sizing data for horizontal piping are based on the pipes flowing full.
| SIZE OF PIPE | FLOW (1/8 inch per foot slope) |
MAXIMUM ALLOWABLE HORIZONTAL PROJECTED ROOF AREAS AT VARIOUS RAINFALL RATES (square feet) |
|||||
| inches | gpm | 1 (in/h) | 2 (in/h) | 3 (in/h) | 4 (in/h) | 5 (in/h) | 6 (in/h) |
| 3 | 34 | 3288 | 1644 | 1096 | 822 | 657 | 548 |
| 4 | 78 | 7520 | 3760 | 2506 | 1880 | 1504 | 1253 |
| 5 | 139 | 13360 | 6680 | 4453 | 3340 | 2672 | 2227 |
| 6 | 222 | 21400 | 10700 | 7133 | 5350 | 4280 | 3566 |
| 8 | 478 | 46000 | 23000 | 15330 | 11500 | 9200 | 7670 |
| 10 | 860 | 82800 | 41400 | 27600 | 20700 | 16580 | 13800 |
| 12 | 1384 | 133200 | 66600 | 44400 | 33300 | 26650 | 22200 |
| 15 | 2473 | 238000 | 119000 | 79333 | 59500 | 47600 | 39650 |
| SIZE OF PIPE | FLOW ( 1/4 inch per foot slope) |
MAXIMUM ALLOWABLE HORIZONTAL PROJECTED ROOF AREAS AT VARIOUS RAINFALL RATES (square feet) |
|||||
| inches | gpm | 1 (in/h) | 2 (in/h) | 3 (in/h) | 4 (in/h) | 5 (in/h) | 6 (in/h) |
| 3 | 48 | 4640 | 2320 | 1546 | 1160 | 928 | 773 |
| 4 | 110 | 10600 | 5300 | 3533 | 2650 | 2120 | 1766 |
| 5 | 196 | 18880 | 9440 | 6293 | 4720 | 3776 | 3146 |
| 6 | 314 | 30200 | 15100 | 10066 | 7550 | 6040 | 5033 |
| 8 | 677 | 65200 | 32600 | 21733 | 16300 | 13040 | 10866 |
| 10 | 1214 | 116800 | 58400 | 38950 | 29200 | 23350 | 19450 |
| 12 | 1953 | 188000 | 94000 | 62600 | 47000 | 37600 | 31350 |
| 15 | 3491 | 336000 | 168000 | 112000 | 84000 | 67250 | 56000 |
| SIZE OF PIPE | FLOW ( 1/2 inch per foot slope) |
MAXIMUM ALLOWABLE HORIZONTAL PROJECTED ROOF AREAS AT VARIOUS RAINFALL RATES (square feet) |
|||||
| inches | gpm | 1 (in/h) | 2 (in/h) | 3 (in/h) | 4 (in/h) | 5 (in/h) | 6 (in/h) |
| 3 | 68 | 6576 | 3288 | 2192 | 1644 | 1310 | 1096 |
| 4 | 156 | 15040 | 7520 | 5010 | 3760 | 3010 | 2500 |
| 5 | 278 | 26720 | 13360 | 8900 | 6680 | 5320 | 4450 |
| 6 | 445 | 42800 | 21400 | 14267 | 10700 | 8580 | 7140 |
| 8 | 956 | 92000 | 46000 | 30650 | 23000 | 18400 | 15320 |
| 10 | 1721 | 165600 | 82800 | 55200 | 41400 | 33150 | 27600 |
| 12 | 2768 | 266400 | 133200 | 88800 | 66600 | 53200 | 44400 |
| 15 | 4946 | 476000 | 238000 | 158700 | 119000 | 95200 | 79300 |
Notes:
1 The sizing data for horizontal piping are based on the pipes flowing full.
2 For rainfall rates other than those listed, determine the allowable roof area by dividing the area given in the 1 inch per hour (25.4 mm/h) column by the
desired rainfall rate.
Window areaways at a
maximum of 10 square feet (0.93 m2) in area shall be
permitted to discharge to the subsoil drains through a 2 inch
(50 mm) pipe. However, window areaways exceeding 10
square feet (0.93 m2) in area shall be handled in the manner
provided for entrance areaways (see Section 1101.8).
Public filling stations and motor vehicle
washing establishments shall have the paved area sloped
toward sumps or gratings within the property lines. Curbs
not less than 6 inches (152 mm) high shall be placed where
required to direct water to gratings or sumps
Where the occupant creates surface
water drainage, the sumps, gratings, or floor drains shall be
piped to a storm drain or an approved water course.
Roof drainage shall comply with 1
Section 1101.12.1 and Section 1101.12.2.
Roof areas of a
building shall be drained by roof drains or gutters. The
location and sizing of drains and gutters shall be coordinated
with the structural design and pitch of the roof.
Unless otherwise required by the Authority Having
Jurisdiction, roof drains, gutters, vertical conductors or
leaders, and horizontal storm drains for primary
drainage shall be sized based on a storm of 60 minutes
duration and 100 year return period. Refer to Table D
101.1 (in Appendix D) for 100 year, 60 minute storms
at various locations.
Secondary (emergency) roof drainage shall be provided by one of the
methods specified in Section 1101.12.2.1 or Section
1101.12.2.2.
Secondary roof drainage shall be provided by an
open-sided roof or scuppers where the roof
perimeter construction extends above the roof in
such a manner that water will be entrapped. An
open-sided roof or scuppers shall be sized to
prevent the depth of ponding water from
exceeding that for which the roof was designed as
determined by Section 1101.12.1. Scupper openings
shall be not less than 4 inches (102 mm) high
and have a width equal to the circumference of the
roof drain required for the area served, sized in
accordance with Table 1101.12.
TABLE 1101.12
SIZING ROOF DRAINS, LEADERS, AND VERTICAL RAINWATER PIPING2, 3
For SI units: 1 inch = 25 mm, 1 gallon per minute = 0.06 L/s, 1 inch per hour = 25.4 mm/h, 1 square foot = 0.0929
Notes:
SIZING ROOF DRAINS, LEADERS, AND VERTICAL RAINWATER PIPING2, 3
Notes:
1 Maximum discharge capacity, gpm (L/s) with approximately 1¾ inch (44 mm) head of water at the drain.
2 For rainfall rates other than those listed, determine the allowable roof area by dividing the area given in the 1 inch per hour (25.4 mm/h) column by the
desired rainfall rate.
3 Vertical piping shall be round, square, or rectangular. Square pipe shall be sized to enclose its equivalent roundpipe. Rectangular pipe shall have not less
than the same cross-sectional area as its equivalent round pipe, except that the ratio of its side dimensions shall not exceed 3 to 1.
Secondary
roof drains shall be provided. The secondary roof
drains shall be located not less than 2 inches (51
mm) above the roof surface. The maximum
height of the roof drains shall be a height to prevent the depth of ponding water from
exceeding that for which the roof was designed as
determined by Section 1101.12.1. The secondary
roof drains shall connect to a piping system in
accordance with Section 1101.12.2.2.1 or Section
1101.12.2.2.2.
The
secondary roof drainage system shall be a
separate system of piping, independent of the
primary roof drainage system. The discharge
shall be above grade, in a location observable
by the building occupants or maintenance
personnel. Secondary roof drain systems shall
be sized in accordance with Section 1101.12.1
based on the rainfall rate for which the
primary system is sized.
The
secondary roof drains shall connect to the
vertical piping of the primary storm drainage
conductor downstream of the last horizontal
offset located below the roof. The primary
storm drainage system shall connect to the
building storm water that connects to an
underground public storm sewer. The
combined secondary and primary roof drain
systems shall be sized in accordance with
Section 1103.0 based on double the rainfall
rate for the local area.
Cleanouts for building storm drains
shall comply with the requirements of Section 719.0 of this
code.
Rain
leaders and conductors connected to a building storm
sewer shall have a cleanout installed at the base of the
outside leader or outside conductor before it connects
to the horizontal drain.
Rainwater sumps serving
"public use" occupancy buildings shall be provided with
dual pumps arranged to function alternately in case of over- Ilo ad or mechanical failure. Pumps rated 600 V or less shall
comply with UL 778 and shall be installed in accordance
with the manufacturer's installation instructions.
Leaders
and storm drains, where connected to a combined sewer,
shall be trapped. Floor and area drains connected to a storm
drain shall be trapped.
Exception: Traps shall not be required where roof drains, rain leaders, and other inlets are at locations allowed under Section 906.0, Vent Termination.
Exception: Traps shall not be required where roof drains, rain leaders, and other inlets are at locations allowed under Section 906.0, Vent Termination.
No trap shall be
required for leaders or conductors that are connected to
a sewer carrying storm water exclusively.
Traps, where installed for individual
conductors, shall be the same size as the horizontal
drain to which they are connected.
Individual storm-water traps shall be installed
on the stormwater drain branch serving each stormwater
inlet, or a single trap shall be installed in the
main storm drain just before its connection with the
combined building sewer. Such traps shall be provided
with an accessible cleanout on the outlet side of the trap.
Leaders
or conductors shall not be used as soil, waste, or vent pipes
nor shall soil, waste, or vent pipes be used as leaders or
conductors.
Leaders installed
along alleyways, driveways, or other locations where
exposed to damage shall be protected by metal guards,
recessed into the wall, or constructed from ferrous pipe.
The sanitary and storm drainage system of a
building shall be entirely separate, except where a
combined sewer is used, in which case the building
storm drain shall be connected in the same horizontal
plane through a single wye fitting to the combined
building sewer not less than 10 feet (3048 mm) downstream
from a soil stack.
Roof drains shall be constructed of
aluminum, cast-iron, copper alloy of not more than 15
percent zinc, leaded nickel bronze, stainless steel, ABS,
PVC, polypropylene, polyethylene, or nylon and shall
comply with ASME A112.3.1 or ASME A112.6.4.
Roof drains shall have
domed strainers.
Exception: Roof drain strainers for use on sun decks, parking decks, and similar areas that are normally serviced and maintained, shall be permitted to be of the flat surface type. Such roof drain strainers shall be level with the deck.
Exception: Roof drain strainers for use on sun decks, parking decks, and similar areas that are normally serviced and maintained, shall be permitted to be of the flat surface type. Such roof drain strainers shall be level with the deck.
Connection between the
roof and roof drains that pass through the roof and into the
interior of the building shall be made watertight by the use
of proper flashing material.
Where lead flashing material
is used, it shall be not less than 4 pounds per square
foot (lb/ft2) (19 kg/m2).
Where copper flashing
material is used, it shall be not less than 12 ounces per
square foot (oz/ft2) (3.7 kg/m2).
Vertical
conductors and leaders shall be sized on the basis of the
maximum projected roof area and Table 1101.12.
The size of building storm drains or building
storm sewers or their horizontal branches shall be based
upon the maximum projected roof or paved area to be
handled and Table 1101.8.
The size of semi-circular
gutters shall be based on the maximum projected roof area
and Table 1103.3.
For SI units: 1 inch = 25 mm, 1⁄16 inch per foot = 5.2 mm/m, 1 inch per hour = 25.4 mm/h, 1 square foot = 0.0929 m2
| DIAMETER OF GUTTER (1⁄16 inch per foot slope) |
MAXIMUM RAINFALL RATES BASED ON ROOF AREA (square feet) |
||||
| inches | 2 (in/h) | 3 (in/h) | 4 (in/h) | 5 (in/h) | 6 (in/h) |
| 3 | 340 | 226 | 170 | 136 | 113 |
| 4 | 720 | 480 | 360 | 288 | 240 |
| 5 | 1250 | 834 | 625 | 500 | 416 |
| 6 | 1920 | 1280 | 960 | 768 | 640 |
| 7 | 2760 | 1840 | 1380 | 1100 | 918 |
| 8 | 3980 | 2655 | 1990 | 1590 | 1325 |
| 10 | 7200 | 4800 | 3600 | 2880 | 2400 |
| DIAMETER OF GUTTER (1⁄8 inch per foot slope) |
MAXIMUM RAINFALL RATES BASED ON ROOF AREA (square feet) |
||||
| inches | 2 (in/h) | 3 (in/h) | 4 (in/h) | 5 (in/h) | 6 (in/h) |
| 3 | 480 | 320 | 240 | 192 | 160 |
| 4 | 1020 | 681 | 510 | 408 | 340 |
| 5 | 1760 | 1172 | 880 | 704 | 587 |
| 6 | 2720 | 1815 | 1360 | 1085 | 905 |
| 7 | 3900 | 2600 | 1950 | 1560 | 1300 |
| 8 | 5600 | 3740 | 2800 | 2240 | 1870 |
| 10 | 10200 | 6800 | 5100 | 4080 | 3400 |
| DIAMETER OF GUTTER (1⁄4 inch per foot slope) |
MAXIMUM RAINFALL RATES BASED ON ROOF AREA (square feet) |
||||
| inches | 2 (in/h) | 3 (in/h) | 4 (in/h) | 5 (in/h) | 6 (in/h) |
| 3 | 680 | 454 | 340 | 272 | 226 |
| 4 | 1440 | 960 | 720 | 576 | 480 |
| 5 | 2500 | 1668 | 1250 | 1000 | 834 |
| 6 | 3840 | 2560 | 1920 | 1536 | 1280 |
| 7 | 5520 | 3680 | 2760 | 2205 | 1840 |
| 8 | 7960 | 5310 | 3980 | 3180 | 2655 |
| 10 | 14400 | 9600 | 7200 | 5750 | 4800 |
| DIAMETER OF GUTTER (1⁄2 inch per foot slope) |
MAXIMUM RAINFALL RATES BASED ON ROOF AREA (square feet) |
||||
| inches | 2 (in/h) | 3 (in/h) | 4 (in/h) | 5 (in/h) | 6 (in/h) |
| 3 | 960 | 640 | 480 | 384 | 320 |
| 4 | 2040 | 1360 | 1020 | 816 | 680 |
| 5 | 3540 | 2360 | 1770 | 1415 | 1180 |
| 6 | 5540 | 3695 | 2770 | 2220 | 1850 |
| 7 | 7800 | 5200 | 3900 | 3120 | 2600 |
| 8 | 11200 | 7460 | 5600 | 4480 | 3730 |
| 10 | 20000 | 13330 | 10000 | 8000 | 6660 |
Where vertical
walls project above a roof so as to permit storm water to
drain to the roof area below, the adjacent roof area shall
be permitted to be computed from Table 1101.12 as
follows:
- For one wall - add 50 percent of the wall area to the roof area figures.
- For two adjacent walls of equal height - add 35 percent of the total wall areas.
- For two adjacent walls of unequal height - add 35 percent of the total common height and add 50 percent of the remaining height of the highest wall.
- Two opposite walls of same height - add no additional area.
- Two opposite walls of differing heights - add 50 percent of the wall area above the top of lower wall.
- Walls on three sides - add 50 percent of the area of the inner wall below the top of the lowest wall, plus allowance for the area of the wall above the top of the lowest wall, in accordance with Section 1103.4(3) and Section 1103.4(5) above.
- Walls on four sides - no allowance for wall areas below the top of the lowest wall - add for areas above the top of the lowest wall in accordance with Section 1103.4(1), Section 11 03.4(3), Section 1103.4(5), and Section 1103.4(6) above.
Where there is a continuous or semi-continuous
discharge into the building storm drain or
building storm sewer, as from a pump, ejector, air-conditioning
plant, or similar device, 1 gpm (0.06 L/s) of such
discharge shall be computed as being equivalent to 24
square feet (2.2 m2) of roof area, based upon a rate of rainfall
of 4 inches per hour (in/h) (102 mm/h).
In lieu of sizing the storm drainage
system in accordance with Section 1103.0, the roof
drainage shall be permitted to be sized on the basis of
controlled flow and storage of the storm water on the roof,
provided the following conditions are met:
- The water from a 25 year-frequency storm shall not be stored on the roof exceeding 24 hours.
- During the storm, the water depth on the roof shall not
exceed the depths specified in Table 1105.1(1).
For SI units: 1 inch = 25.4 mmTABLE 1105.1(1)
CONTROLLED-FLOW MAXIMUM ROOF WATER DEPTHROOF RISE*
(inches)MAXIMUM WATER DEPTH
AT DRAIN
(inches)Flat 3 2 4 4 5 6 6
* Vertical measurement from the roof surface at the drain to the highest point of the roof surface served by the drain, ignoring a local depression immediately adjacent to the drain. - Not less than two drains shall be installed in roof areas of 10000 square feet (929 m2) or less, and not less than one additional drain shall be installed for each 10000 square feet (929 m2) of roof area exceeding 10000 square feet (929 m2).
- Each roof drain shall have a precalibrated, fixed (nonadjustable), and proportional weir (notched) in a standing water collar inside the strainer. No mechanical devices or valves shall be allowed.
- Pipe sizing shall be based on the pre-calibrated rate of flow (gpm) (L/s) of the pre-calibrated weir for the maximum allowable water depth, and Table 1101.8 and Table 1101.12.
- The height of stones or other granular material above the waterproofed surface shall not be considered in water depth measurement, and the roof surface in the vicinity of the drain shall not be recessed to create a reservoir.
- Roof design, where controlled-flow roof drainage is used, shall be such that the design roof live load is not less than 30 lb/ft2 (146 kg/m2) to provide a safety factor exceeding the 15 lb/ft2 (73 kg/m2) represented by the depth of water stored on the roof in accordance with Table 1105.1(1).
- Scuppers shall be provided in parapet walls. The
distance of scupper bottoms above the roof level at the
drains shall not exceed the maximum distances specified
in Table 1105.1 (2).
For SI units: 1 inch = 25.4 mmTABLE 1105.1(2)
DISTANCE OF SCUPPER BOTTOMS ABOVE ROOFROOF RISE*
(inches)ABOVE ROOF LEVEL
AT DRAIN
(inches)Flat 3 2 4 4 5 6 6
* Vertical measurement from the roof surface at the drain to the highest point of the roof surface served by the drain, ignoring a local depression immediately adjacent to the drain. - Scupper openings shall be not less than 4 inches (102 mm) high and have a width equal to the circumference of the roof drain required for the area served, sized in accordance with Table 1101.12.
- Flashings shall extend above the top of the scuppers.
- At a wall or parapet, 45 degree (0.79 rad) cants shall be installed.
- Separate storm and sanitary drainage systems shall be provided within the building.
- Calculations for the roof drainage system shall be submitted along with the plans to the Authority Having Jurisdiction for approval.
Drains on setback roofs shall be
permitted to be connected to the controlled-flow drainage
systems provided:
- The setback is designed for storing water, or
- The square footage of the setback drainage area is converted as outlined in Section 1105.0 to gpm, and the storm-water pipe sizes in the controlled-flow system are based on the sum of the loads.
- The branch from each of the roof drains that are not provided with controlled flow shall be sized in accordance with Table 1101.12.
New building storm drainage
systems and parts of existing systems that have been
altered, extended, or repaired shall be tested in accordance
with Section 1106.2.1 or Section 1106.2.2 to disclose leaks
and defects.
Except for outside leaders and perforated or open-jointed
drain tile, the piping of storm drain systems shall be tested
upon completion of the rough piping installation by water
or air, except that plastic pipe shall not be tested with air,
and proved tight. The Authority Having Jurisdiction shall
be permitted to require the removal of cleanout plugs to
ascertain whether the pressure has reached parts of the
system. One of the following test methods shall be used in
accordance with Section 1106.2.1 through Section
1106.2.3.
After piping has been installed,
the water test shall be applied to the drainage system,
either to the entire system or to sections. Where the test
is applied to the entire system, all openings in the
piping shall be tightly closed except for the highest
opening, and the system shall be filled with water to
the point of overflow. Where the system is tested in
sections, each opening shall be tightly plugged except
for the highest opening of the section under test, and
each section shall be filled with water, but no section
shall be tested with less than a 10 foot (3048 mm) head
of water. In testing successive sections, not less than
the upper 10 feet (3048 mm) of the next preceding
section shall be tested so that no joint of pipe in the building except the uppermost 10 feet (3048 mm) of a
roof drainage system, which shall be filled with water
to the flood level of the uppermost roof drain, shall
have been submitted to a test of less than 10 foot (3048
mm) head of water. The water shall be kept in the
system or in the portion under test for not less than 15
minutes before inspection starts; the system shall then
be tight.
The air test shall be made by
attaching an air compressor testing apparatus to a suitable
opening after closing other inlets and outlets to the
system, forcing air into the system until there is a
uniform gauge pressure of 5 pounds-force per square
inch (psi) (34 kPa) or sufficient pressure to balance a
column of mercury 10 inches (34 kPa) in height. This
pressure shall be held without introduction of additional
air for a period of not less than 15 minutes.
Where circumstances exist that
make air and water tests described in Section 1106.2.1
and Section 1106.2.2 impractical, see Section 105.3.