CHAPTER 6 - Design & Construction Standards for Storm Sewers, Drainage Ways, Sump Pump Discharge Lines and Storm Water Detention Facilities
6.01 Introduction
6.02 Design Standards
6.03 Design Calculations Requirements
6.04 Right-of-way & Easement Dedications
6.05 Town's Participation in Cost
6.06 Specifications and Special Provisions
6.07 Standard Details
6.01 INTRODUCTION
All subdivisions, regardless of size, within the corporate limits or under the control of the Town, shall include a storm water drainage system designed in such a way as to do and accomplish the requirements of this chapter of the Manual. The design of all storm water facilities proposed and funded by the Town shall also meet the requirements of the Chapter.
Developers shall be allowed to tap into any existing portion of the Town's storm water drainage system if the requirements of this Chapter have been or will be met and the requirements of Section 7.22 and Section 7.31 of the Municipal Code which enumerate the requirements for tap-on or hook-up charges for designated trunk line storm sewers and the requirements for payment of a fee in lieu of constructing storm water detention/retention facilities
6.02 DESIGN STANDARD
All subdivisions shall include a storm water drainage system designed in such a way to provide that all lots and out-lots in the subdivision will be graded and shaped so as to drain property within the subdivision and such additional land as is in the natural drainage way by gravity to catch basins, inlets, detention/retention facilities and drainage ways with adequate outlet.
- Storm Sewers
- In all new developments except those zoned R-1AA, R-1A,
R-1B, or R-2, the Developer will be required to provide
a twelve (12) inch (300 mm) diameter storm sewer lateral
to a point on each lot; said point to be a point that will
accommodate the natural drainage of the lot served. The
lateral shall be attached to the primary sewer at a drainage
structure.
- Design formula: Unless otherwise approved by the
Town Engineer, formulas to be used in connection with
the calculation of run-off reasonably expected from
the minimum design storm shall be the Rational Method
for total contributing areas of twenty (20) acres (8
hectares) or less and the Soil Conservation Service
Method as outlined in their Technical Release No. 55
for areas greater than 20 acres. Calculations are to
be submitted substantially in the form provided in Exhibit
P of the Appendix.
- Minimum Design Storm: The minimum design storm used
in calculating run-off in the Design Formula will be
the average rainfall intensity associated with an average
recurrence interval of five (5) years for the storm
period calculated by the Time of Concentration as outlined
by the latest Technical Letters of the Illinois State
Water Survey for rainfall frequencies. The corresponding
charts and tables have been provided in Exhibit P of
the Appendix for time of concentration, run-off factors
and coefficients and frequency intensities for use in
either method for run-off estimation.
- Match 0.90 points of diameter when changing from
one size to another where feasible.
- Design formula: Unless otherwise approved by the
Town Engineer, formulas to be used in connection with
the calculation of run-off reasonably expected from
the minimum design storm shall be the Rational Method
for total contributing areas of twenty (20) acres (8
hectares) or less and the Soil Conservation Service
Method as outlined in their Technical Release No. 55
for areas greater than 20 acres. Calculations are to
be submitted substantially in the form provided in Exhibit
P of the Appendix.
- The storm water drainage system shall connect all inlets
and catch basins to a storm sewer, pipe or conduit of sufficient
size, grade and capacity to carry the run-off reasonably
expected from the Minimum Design Storm on the area in the
natural drainage area if that area is improved with the
type of improvements permitted and to a maximum density
authorized by the then-existing zoning ordinances of the
Town for property within the corporate limits and the land
use element of the Town's Comprehensive Plan for property
outside the corporate limits provided, however, no storm
sewer shall be less than twelve (12) inches (300mm) in diameter.
- The storm water drainage system shall connect all storm
sewers to other storm sewers or improved drainage ways of
sufficient size, grade, and capacity to carry the runoff
reasonably expected from the Minimum Design Storm on the
area in the natural drainage area if that area was improved
with the type of improvements permitted and to the maximum
density authorized by the then-existing zoning ordinances
of the Town for property within the corporate limits and
the land use element of the Town's Comprehensive Plan for
property outside the corporate limits.
- Manholes
- Public manholes shall be installed at the end of each storm sewer line, at all changes in grade or alignment, at all intersections and at distances not greater than 400 feet (120 m) between manholes for sewers of 15 inches (375 mm) or less and 500 feet (150 m) for sewers 18 to 30 inches (450 mm to 750 mm). The Town Engineer in larger sewers will permit greater spacing.
- Public manholes in improved streets or other hard surfaced public rights-of-way accessible to vehicular traffic shall be not more than 800 feet (240m) apart.
- Minimum drop in a manhole shall be 30 mm (0.1 ft) and the desired maximum drop in a manhole shall be 600 mm (24 inches.)
- Manholes shall be constructed in accordance with
Standard Detail 6.07A or B.
- Inlets
- Inlets for local streets shall be provided for all low points and the maximum spacing shall not exceed four hundred (400) feet, except that the first inlet shall be spaced approximately four hundred (400) feet from the high point or at no greater distance than six hundred (600) feet when approved by the Town Engineer. Inlet spacing for all other streets must meet Illinois Department of Transportation Design and Environment Manual criteria.
- Inlets shall be designed in accordance with Standard
Drawing 6.07 C or D.
- A flood route shall be provided through the proposed
development. The flood route shall be designed for the runoff
expected from a 100-year storm frequency in post development
conditions or pre-development conditions, whichever generates
higher flow.
- In all new developments except those zoned R-1AA, R-1A,
R-1B, or R-2, the Developer will be required to provide
a twelve (12) inch (300 mm) diameter storm sewer lateral
to a point on each lot; said point to be a point that will
accommodate the natural drainage of the lot served. The
lateral shall be attached to the primary sewer at a drainage
structure.
- Drainage Ways
The Town has constructed storm water detention/retention facilities and is contemplating others at certain locations to serve upstream watersheds not yet fully developed, and if a proposed development lies within an area served by an adequate existing or proposed facility, at the option of the Town Engineer, the Project will not include a storm water detention/retention facility. The local storm sewer system and drainage ways will discharge directly to that facility or an adequate trunk line storm sewer or drainage way feeding it. In such a case, the Developer will pay a fee in lieu of constructing a separate facility, computed in accordance with the requirements of Section 7.31 of the Municipal Code.
- All drainage ways through the proposed development shall
be improved to a size and in a way adequate to carry the
runoff reasonably expected from the Minimum Design Storm
on the area in the natural drainage area if that area was
improved with the type of improvements permitted and to
the maximum density authorized by the then-existing zoning
ordinances of the Town for property within the corporate
limits and the land use element of the Town's Comprehensive
Plan for property outside the corporate limits.
- Design Formula: Unless otherwise approved by the Town Engineer, formulas to be used in connection with the calculation of runoff reasonably expected from the Minimum Design Storm shall be the Rational Method for total contributing areas of twenty (20) acres (8 hectares) or less and the Soil Conservation Service Method as outlined in their Technical Release No. 55 for areas greater than 20 acres (8 hectares). Calculations shall be submitted substantially in the form provided in Exhibit P of the Appendix.
- Minimum Design Storm: The Minimum Design
Storm used in calculating runoff in the Design Formula
will be the average rainfall intensity associated with
an average recurrence interval of twenty-five (25) years
for the storm period calculated by the Time of concentration
as outlined by the latest Technical Letters of the Illinois
State Water Survey for rainfall frequencies. The corresponding
charts and tables have been provided in Exhibit P of
the Appendix for Time of Concentration, runoff factors,
and coefficients and frequency intensities for use in
either method for runoff estimation.
- Drainage ways shall have a flat bottom, maximum 3:1
side slopes, the top of the bank shall be constructed one
foot (0.3m) above computed water surface elevation for the
Minimum Design Storm, and have a ten (10) foot (3m) maintenance/access
lane on each side of the drainage way.
- All drainage ways through the proposed development shall
be improved to a size and in a way adequate to carry the
runoff reasonably expected from the Minimum Design Storm
on the area in the natural drainage area if that area was
improved with the type of improvements permitted and to
the maximum density authorized by the then-existing zoning
ordinances of the Town for property within the corporate
limits and the land use element of the Town's Comprehensive
Plan for property outside the corporate limits.
- Retention and Detention Facilities
- No development shall be authorized in the Town unless
there is an adequate outlet or the Town has approved retention
or detention facilities. The applicant shall show by his
detailed calculations that the outlet is adequate, and the
calculations must be acceptable to the Town. In the event
the Town determines the outlet is not adequate, the developer
shall construct retention or detention facilities. Such
facilities shall be designed based on the Design Formula.
In lieu of providing retention or detention facilities,
the developer shall, upon Town direction, pay a fee as provided
in Section 7.31 of the Municipal Code. Such fee may be refunded
as provided in said Section of the Municipal Code.
- Design Formula: Unless otherwise approved by the Town Engineer, formulas to be used in connection with the calculation of runoff volumes and allowable release rates reasonably expected from the Minimum Design Storm shall be the Rational Method as outlined on the latest Illinois Department of Transportation Drainage Manual for total contributing areas of twenty (20) acres (8 hectares) or less and the Soil Conservation Hydrograph Method for areas greater than 20 acres (8 hectares). The corresponding instructions, charts, tables and forms have been provided in Exhibit P of the Appendix of this Manual for use in either method of calculation.
- Minimum Design Storm:
- Storage Volume when using the Soil Conservation Hydrograph Method will be determined from inflow hydrographs generated by the Design Formula using a minimum design storm with a range of rainfall intensities associated with an average recurrence interval of one hundred (100) years and an assumed coefficient for the particular post development zoning district as set forth in Exhibit P of the Appendix of this manual.
- Storage Volume when using the Rational Method will be the volume generated by the difference between average runoffs of 100-year rainfall frequency in post development condition and three year rainfall frequency in pre-development condition, assuming such difference occurs for one hour. The average discharge being half of the peak discharge calculated by the Rational Method.
- Allowable Release Rate will be determined
by the Design Formula using a minimum design storm
with an average rainfall intensity associated with
an average recurrence interval of three (3) years
for the storm period calculated by the Time of Concentration
as outlined by the latest Technical Letters of the
Illinois State Water Survey for rainfall frequencies.
Runoff coefficients or CN numbers shall reflect
pre-developed conditions of the watershed.
- Bank Stabilization
- Retention facilities shall be provided with wave shelves along the entire perimeter in accordance with the standards in this Manual.
- Retention/Detention facilities shall have a maximum 4:1 slope.
- Shoreline surfaces subject to wave shall be stabilized
with structural materials such as riprap, cement blocks
or matting, retaining or slope walls, etc.
- Under Drains:
Detention facilities to be dedicated to the public for ownership and maintenance by the Town shall include a system of under drains to insure a dry bottom.
- Pipe Materials: Under drains shall be constructed of rigid perforated PVC pipe, SDR 35 or stronger.
- Fabric Envelope: Under drainpipe shall be encased in an envelope of fabric as specified in Section 1080.01 of IDOT Standard Specifications for Road and Bridge Construction.
- Pipe Size: minimum 6 inch (150 mm).
- Clean outs: At ends of runs, junctions, and maximum every 300 feet (90m) as per standard 6.07 – J.
- Tracer Wire: all under drains shall be buried
with a tracer wire. Trace wire shall be #12 THWN single
conductor solid copper cable. Tracer wires shall be
terminated at cleanouts as shown in Standard Drawing
6.07 – K.
- Earthen Dams:
when dedicated to the public for ownership and maintenance by the Town, earthen dams shall meet the following criteria.- Side Slope: 4:1 or flatter
- Minimum 10-foot (3m) wide flat crest for access
by maintenance equipment.
All earthen dams, whether public or privately owned and maintained shall meet the following: - Freeboard: All earthen dams shall be constructed with a minimum of one foot (300 mm) of freeboard over the maximum anticipated water level in the emergency spillway.
- All earthen dams shall include an impervious compacted clay core. The core shall be of sufficient width to allow for mechanical compaction and of sufficient depth to penetrate the overburden of topsoil, keying into the underlying strata of virgin clay.
- The developer shall be responsible for obtaining
all construction permits required by governmental agencies.
- Emergency Spillway:
All detention and retention facilities, whether publicly or privately owned and maintained shall include an emergency spillway.
- Emergency spillways shall, wherever feasible, be constructed in virgin ground.
- Erosion Protection: emergency spillways shall be protected from erosion with approved surface paving or vertical cutoff walls appropriate for the size of the impoundment and the height of the spillway crest.
- Capacity: emergency spillways shall be sized for
no less than 75% of the maximum peak inflow into the
basin.
- No development shall be authorized in the Town unless
there is an adequate outlet or the Town has approved retention
or detention facilities. The applicant shall show by his
detailed calculations that the outlet is adequate, and the
calculations must be acceptable to the Town. In the event
the Town determines the outlet is not adequate, the developer
shall construct retention or detention facilities. Such
facilities shall be designed based on the Design Formula.
In lieu of providing retention or detention facilities,
the developer shall, upon Town direction, pay a fee as provided
in Section 7.31 of the Municipal Code. Such fee may be refunded
as provided in said Section of the Municipal Code.
- Adequate Outfall shall be provided. If the outlet
is not adequate, then retention or detention shall be provided.
The applicant should show by his detailed calculations that
the outlet is adequate based on the Design Formula and the calculations
are acceptable by the Town.
- Design Formula: Unless otherwise approved by
the Town Engineer, formulas to be used in connection with
the calculation of runoff reasonably expected from the Minimum
Design Storm shall be the Rational Method for total contributing
areas of twenty (20) acres (8 hectares) or less and the
Soil Conservation Service Method as outlined in their Technical
Release No. 55 for areas greater than 20 acres (8 hectares).
- Minimum Design Storm used in calculating runoff
in the Design Formula will be the average rainfall intensity
associated with an average recurrence interval of twenty-five
(25) years for waterways and five (5) years for storm sewer
for the storm period calculated by the Time of Concentration
as outlined by the latest Technical Letters of the Illinois
State Water Survey for rainfall frequencies.
- Design Formula: Unless otherwise approved by
the Town Engineer, formulas to be used in connection with
the calculation of runoff reasonably expected from the Minimum
Design Storm shall be the Rational Method for total contributing
areas of twenty (20) acres (8 hectares) or less and the
Soil Conservation Service Method as outlined in their Technical
Release No. 55 for areas greater than 20 acres (8 hectares).
- Sump Pump Discharge
- In all new developments zoned R-1AA, R-1A, R-1B, and
R-2, the developer will be required to provide a minimum
two (2) inch (50 mm) diameter sump pump discharge lateral
to a point on each lot; said point to be a point that will
accommodate the natural sub-surface discharge from around
the foundation of the building served. The lateral shall
be attached to the primary sump pump discharge conduit by
the installation of a tee or wye connection.
- The primary sump pump discharge system shall connect
all laterals to a storm sewer, pipe or conduit of sufficient
size, grade and capacity to carry the discharge reasonably
expected from the area improved with the maximum density
authorized by the then-existing zoning ordinances of the
Town. No primary sump pump discharge conduit shall be less
than six (6) inches (150 mm) in diameter or greater than
ten (10) inches in diameter. For conduit greater than ten
(10) inches (250 mm) in diameter, the design method of storm
sewers shall govern.
- The primary sump pump discharge system shall connect
all conduit to other storm sewers, inlets or catch basins,
manholes or improved drainage ways of sufficient size, grade
and capacity to carry the discharge reasonably expected
in addition to the surface runoff expected from the Minimum
Design Storm for the design of storm sewers and drainage
ways as described in this section.
- Cleanouts:
- Cleanouts shall be installed at the end of each primary sump pump discharge line, at all changes in grade or alignment, and at distances not greater than 200 feet (60 m) between cleanouts or between cleanouts and manholes or inlets. Inlets or manholes may be substituted for cleanouts located within the public right-of-way.
- Curb Marking of Cleanouts and Service tees: At the
time the curb and gutter is poured, the contractor shall
mark the top of the curb with "P" to mark location of
said cleanout or sump pump service tee.
- No sump pump discharge lateral or primary conduit shall
be installed beneath a public street pavement. The Town
will not accept for maintenance any primary sump pump discharge
line located along rear or side lot lines.
- All sump pump discharge conduits not constructed of metallic material shall be installed with tracer location wire. Tracer wire shall be #12 THWN single conductor solid copper cable. Tracer wire shall be terminated at cleanouts as shown in Standard Drawing 6.07-K.
- In all new developments zoned R-1AA, R-1A, R-1B, and
R-2, the developer will be required to provide a minimum
two (2) inch (50 mm) diameter sump pump discharge lateral
to a point on each lot; said point to be a point that will
accommodate the natural sub-surface discharge from around
the foundation of the building served. The lateral shall
be attached to the primary sump pump discharge conduit by
the installation of a tee or wye connection.
6.03 DESIGN CALCULATIONS REQUIREMENTS
Calculations required to demonstrate compliance with the design standards enumerated in the previous section of this Manual shall be submitted substantially in the form and content as shown and provided in Exhibit P of the Appendix. Calculations submitted with Preliminary Plans are not required to be of greater detail as the calculations required to be submitted with Public Improvement Engineering Plans and Specifications.
6.04 RIGHT-OF-WAY AND EASEMENT DEDICATIONS
- Drainage Ways shall be located in dedicated public
rights-of-way. Rights-of-way for drainage ways shall be a minimum
of one hundred (100) feet (30m) wide. This minimum width shall
be increased if the Town Engineer shall determine that the drainage
way's hydraulic capacity is inadequate to properly serve its
drainage function.
- Storm Sewers shall be located in public easements
or dedicated public rights-of-way. Such easements and rights-of-way
shall be of sufficient width and the storm sewer shall be installed
at such locations therein as to permit open cut installation,
maintenance and repair within the confines of the easement or
right-of-way without relocation or other unreasonable interference
with other public utilities located therein and so as to meet
the following minimum standards:
- Fifteen (15) feet (4.5 m) in width plus five (5) feet
(1.5 m) for each additional utility for storm sewers 24
inches (600 mm) in diameter and ten (10) feet (3 m) for
water main or other sewers.
- Two (2) additional feet in width for each 12 inches
(300 mm) or portion thereof, of additional storm sewer diameter
provided in excess of 24 inches (600 mm).
- Additional width may be required if storm sewers exceed
fifteen (15) feet (4.5 m) in depth.
- Fifteen (15) feet (4.5 m) in width plus five (5) feet
(1.5 m) for each additional utility for storm sewers 24
inches (600 mm) in diameter and ten (10) feet (3 m) for
water main or other sewers.
- Sump Pump Discharge Line shall be located in public
easements or dedicated public rights-of-way. Such easements
and rights-of-way shall be of sufficient width and the conduit
shall be installed at such locations therein as to permit open
cut installation, maintenance and repair within the confines
of the easement or right-of-way without relocation or other
unreasonable interference with other public utilities located
therein and so as to meet the following minimum standards:
- Ten (10) feet (3 m) in width plus five (5) feet (1.5 m) for each additional utility for sump pump discharge line.
6.05 TOWN'S PARTICIPATION IN COST
- Storm sewers and Drainage ways
Where it is necessary to construct storm sewers and drainage ways through land not being developed, the Town shall pay a percentage of the cost of the storm sewer or drainage way, provided funds are available, based on the percentage of the drainage area contributing to the storm sewer or drainage way downstream from the development. The Developer's percentage shall be based on the percentage of the drainage area coming through and including his development. The Developer is required to pay tap-on fees for particular trunk line storm sewers as designated in Section 7.22 of the Municipal Code.
- Detention/Retention Facilities
In all developments not already served by an adequate existing or proposed storm water detention/retention facility, the developer shall provide a storm water detention/retention facility complying with this manual or, a the option of the Town, the Developer shall pay a fee in lieu of providing said detention/retention facility. In those locations already served by an existing storm water detention/retention facility or where the Town is contemplating constructing a detention/retention facility to serve upstream watersheds not yet fully developed, or where the Developer cannot provide adequate storage capacity in a detention/retention facility within his/her development, at the option of the Town, the Developer shall pay a fee in lieu of providing said detention/retention facility, or the deficient volume thereof.
Facilities shall be designed so that local storm sewer systems and drainage ways will discharge directly to proposed or existing detention/retention facilities, or to an adequate trunk line storm sewer and flood route, or drainage way feeding same, which discharges into a proposed or existing storm water detention/retention facility. Where adequate storm sewer or drainage way capacity is not available to convey design runoff to an existing downstream detention/retention facility, an on-site detention/retention facility shall be required.
- Engineering Costs
The Developer will be responsible for all engineering costs for design of storm sewers, drainage ways and detention/retention facilities within his/her development.
6.06 SPECIFICATIONS & SPECIAL PROVISIONS
- Storm Sewers shall use materials and be installed
in the manner meeting or exceeding the requirements, standards,
and specifications contained in the Standard Specifications
for Water and Sewer Main construction in Illinois, the current
edition as then modified, supplemented and amended by this Manual
or the Town Engineer. These modifications, amendments and amplifications
have been provided in this Chapter of the Manual.
- Drainage Ways & Retention or Detention Facilities
shall be constructed in the manner meeting or exceeding the
requirements, standards and specifications contained in the
applicable sections of the "Standard Specifications for Road
and Bridge Construction" for the Illinois Department of Transportation,
the current edition as then modified, supplemented and amended
by this Manual or the Town Engineer. These modifications, amendments
and amplifications have been provided in this Chapter of the
Manual.
- Sump Pump Discharge Lines shall be constructed in
the manner meeting or exceeding the requirements, standards
and specifications contained in the applicable sections of the
"Standard Specifications for Water and Sewer Main Construction
in Illinois", the current edition as then modified, supplemented
and amended by this Manual or the Town Engineer. These modifications
have been provided in this chapter of the Manual.
- Materials:
- Storm Sewer. Materials shall be in accordance
with Section 550 of the Standard Specifications for Road
and Bridge Construction and shall conform to one of the
following:
- Reinforced Concrete Arch Culvert, Storm Drain and Sewer Pipe.
- Reinforced Concrete culvert, Storm Drain and Sewer Pipe.
- Reinforced Concrete Elliptical Culvert, Storm Drain and Sewer Pipe.
- Ductile Iron Pipe Class 150 conforming to A.N.S.I./A.W.W.A.
C-151/A21.51, with single gasket joints meeting A.N.S.I./A.W.W.A.
C-111/A21.11, with standard cement lining as per A.N.S.I./A.W.W.A.
C-104/A21.4 and with bituminous coating as per Section 51-8.1 of A.N.S.I./A.W.W.A. C-151/A21.51.
- Sump Pump Discharge Lines not under pavements
shall be constructed of rigid P.V.C., SDR 35 or stronger,
conforming to Section 1040.10 of the “Standard Specifications
for Road and Bridge Construction”. Sump Pump Discharge Lines
under pavements shall be constructed of the same materials
as storm sewers.
- Storm Sewer. Materials shall be in accordance
with Section 550 of the Standard Specifications for Road
and Bridge Construction and shall conform to one of the
following:
- Special Provisions
- Storm Sewer Special Provisions
Adjustment of Frame of Grate: Final grade for all manhole castings will be determined after the curb and gutter has been poured and the sub-grade and/or base have been constructed. Final adjustment of the frame and grate shall be made in the following manner: After the curb and gutter has been poured and the base constructed the final elevation will be determined by the Town Engineer.
The frame and grate will be adjusted to this elevation in accordance with the Standard Specifications. Any material disturbed while adjusting the frame and grate will be disposed of and all fill made with lean concrete. A maximum of eight (8) inches (200 mm) of adjusting rings shall be allowed.
Jetting of Trenches: All sewer trenches under streets, driveways or sidewalks shall be compacted by jetting or as directed by the Town Engineer.
Granular Cradle: A granular cradle will be required for all sanitary sewers as shown in the Standard Details. Material for the granular cradle shall comply with fine aggregate gradations (FA-1 or FA-2) in accordance with Section 1003.04 of the Standard Specifications.
Trench Backfill: Material for Trench Backfill shall comply with Section 1003.04 of the Standard Specifications for Road and Bridge Construction. All trenches under another sewer or water main, or under existing streets, sidewalks, driveways and curb and gutter shall be backfilled with trench backfill material in accordance with Section 550.07 of the Standard Specifications. Material for Trench Backfill shall comply with Article 1003.04 of the Standard Specifications for fine aggregate gradations (FA-6).
Inlet Type A w/Type 3 Frame and Grate: Section 612 of the Standard Specifications shall govern the construction of Inlets Type A. They shall be built in accordance with the Standard Details for Inlets Type A. Section 614 of the Standard Specifications shall govern the construction of Frame and Grate Type 3. Frame and Grate Type 3 shall be equal to Neenah No. R-3010. The curb box shall be of the open type and the grate shall be Type A. Only cast iron grates shall be used.
Inlet Type H w/Type 50 Frame and Grate: Section 602 shall govern the construction of Inlets Type H. They shall be built in accordance with the Standard Details for Inlets Type H. Section 604 shall govern the construction of Frame and Grate Type 50. Frame and Grate Type 50 shall be equal to Neenah No. R-3067 and grates shall be Type A. Only cast iron grates shall be used.
- Sump Pump Discharge Special Provisions
Sump Pump Discharge Pipes: Material for sump pump discharge conduit shall be polyvinyl chloride (PVC) sewer pipe conforming to ASTM D 3034, type PSM for sizes 4"-10" (100 mm – 250 mm). Minimum Standard Dimension Ratio (SDR) acceptable shall be 35. Material for conduit exceeding size diameter of 10" (250 mm) shall be the same as determined in this Manual for storm sewers. Sump Pump Discharge Cleanouts shall be constructed in accordance with Standard Detail
607-J.
- Storm Sewer Special Provisions
