ASTM C478/C478M-22

Standard Specification for Circular Precast Reinforced Concrete Manhole Sections

ABSTRACT
This specification covers the manufacture and purchase requirements of products used for the assembly and construction of circular vertical precast reinforced concrete manholes and structures used in sewer and water works. Reinforced concrete shall consist of cementitious materials, mineral aggregates, and water, in which steel reinforcement has been embedded in such a manner so that the steel reinforcement and concrete act together. Aggregates shall conform to the specification , except that the requirements for gradation shall not apply. Minimum compressive strength of concrete manhole products covered must meet the requirement. The aggregates shall be sized, graded, proportioned, and mixed with such proportions of cementitious materials and water as will produce as homogeneous concrete mixture of such quality that the products will conform to the test and design requirements. Concrete products shall be subjected to either steam or water curing. Test methods such as compression and absorption testing shall be performed.
SCOPE
1.1 This specification covers the manufacture and purchase requirements of products used for the assembly and construction of circular vertical precast reinforced concrete manholes and structures used in sewer, drainage, and water works.  
1.2 Part I, Sections 1 – 11, of this specification presents general requirements and requirements that are common to each precast concrete product covered by this specification.  
1.3 Part II of this specification presents specific requirements for each manhole product in the following sections:    
Product  
Section  
Grade Rings  
12  
Flat Slab Tops  
13  
Risers and Conical Tops  
14  
Base Sections  
15  
Steps and Ladders  
16  
Note 1: Future products will be included in Part II in a future revision of this specification.  
1.4 The values stated in either inch pound or SI units are to be regarded separately as standard. The SI units are shown in brackets. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.
Note 2: This specification is a manufacturing and purchase specification only and does not include requirements for backfill, or the relationship between field load conditions and the strength requirements of the manhole products and appurtenances. Experience has shown, however, that the successful performance of this product depends upon the proper selection of the product strength, type of foundation and backfill, and care in the field installation of the manhole products and connecting pipes. The owner of the project for which these products are specified herein is cautioned to require inspection at the construction site.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Aug-2022
• ICS: 13.060.30 - Sewage water
• Technical Committee: C13 - Concrete Pipe
• Drafting Committee: C13.06 - Manholes and Specials

Relations

• Refers: ASTM A1064/A1064M-24 - Standard Specification for Carbon-Steel Wire and Welded Wire Reinforcement, Plain and Deformed, for Concrete
• Effective Date: 15-Apr-2024
• Refers: ASTM C989/C989M-24 - Standard Specification for Slag Cement for Use in Concrete and Mortars
• Effective Date: 01-Feb-2024
• Refers: ASTM C39/C39M-23 - Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens
• Effective Date: 01-Dec-2023
• Refers: ASTM C497M-20a - Standard Test Methods for Concrete Pipe, Concrete Box Sections, Manhole Sections, or Tile (Metric)
• Effective Date: 01-May-2020
• Refers: ASTM C497M-20 - Standard Test Methods for Concrete Pipe, Concrete Box Sections, Manhole Sections, or Tile (Metric)
• Effective Date: 15-Feb-2020
• Refers: ASTM C497M-19a - Standard Test Methods for Concrete Pipe, Concrete Box Sections, Manhole Sections, or Tile (Metric)
• Effective Date: 01-Oct-2019
• Refers: ASTM C497-19a - Standard Test Methods for Concrete Pipe, Concrete Box Sections, Manhole Sections, or Tile
• Effective Date: 01-Oct-2019
• Refers: ASTM C309-19 - Standard Specification for Liquid Membrane-Forming Compounds for Curing Concrete
• Effective Date: 15-Jun-2019
• Refers: ASTM C150/C150M-19 - Standard Specification for Portland Cement
• Effective Date: 01-Apr-2019
• Refers: ASTM C497-19 - Standard Test Methods for Concrete Pipe, Concrete Box Sections, Manhole Sections, or Tile
• Effective Date: 01-Jan-2019
• Refers: ASTM C497M-19 - Standard Test Methods for Concrete Pipe, Concrete Box Sections, Manhole Sections, or Tile (Metric)
• Effective Date: 01-Jan-2019
• Refers: ASTM A1064/A1064M-18 - Standard Specification for Carbon-Steel Wire and Welded Wire Reinforcement, Plain and Deformed, for Concrete
• Effective Date: 01-Nov-2018
• Refers: ASTM C497-18b - Standard Test Methods for Concrete Pipe, Manhole Sections, or Tile
• Effective Date: 01-Jun-2018
• Refers: ASTM C497M-18 - Standard Test Methods for Concrete Pipe, Manhole Sections, or Tile (Metric)
• Effective Date: 01-May-2018
• Refers: ASTM C497-18a - Standard Test Methods for Concrete Pipe, Manhole Sections, or Tile
• Effective Date: 01-May-2018

Overview

ASTM C478/C478M-22 is the standard specification for the manufacture and purchase of circular precast reinforced concrete manhole sections. Developed by ASTM International, this standard outlines the quality and design criteria for precast concrete manholes and related structures used in sewer, water, and drainage systems. The specification details the requirements for materials, manufacturing, testing, acceptance, and marking, ensuring these components meet durability, strength, and safety needs for infrastructure projects.

This standard is critical for municipal engineers, contractors, and manufacturers involved in waterworks and utility construction, providing guidelines that promote structural integrity, consistent performance, and long-term reliability of underground utility access structures.

Key Topics

• Scope: Covers circular vertical precast reinforced concrete manhole sections, including grade rings, flat slab tops, risers, conical tops, base sections, steps, and ladders.
• Material Requirements:
  • Reinforced concrete with cementitious materials, aggregates, admixtures, water, and embedded steel reinforcement to ensure unified structural action.
  • Aggregates must conform to ASTM specifications, except for gradation requirements.
  • Acceptable admixtures and fibers may be used for enhanced concrete properties.
• Design Criteria:
  • Minimum compressive strength and physical requirements outlined.
  • Custom and special designs permitted with proper approval and supporting calculations.
• Manufacture & Curing:
  • Strict requirements for batching, mixing, and curing (steam or water curing) promote consistent quality.
  • Permitted combination of various curing techniques as long as compressive strength targets are met.
• Testing & Acceptance:
  • Products evaluated by compressive strength tests and absorption tests.
  • Acceptance can be based on material testing, finished product inspection, and optional proof-of-design tests.
• Product Marking:
  • Includes specification designation, date of manufacture, and manufacturer’s identification.

Applications

ASTM C478/C478M-22 is widely applied in the construction and installation of:

• Sewer Systems: Precast concrete manholes are key access points for inspection, maintenance, and connection of underground sewer pipes.
• Stormwater and Drainage: Manholes provide access and flow control within storm drain infrastructure.
• Waterworks: Used in potable and non-potable water systems for access, monitoring, and system integrity.
• Utility Infrastructure: Supports gas, electrical, and telecommunication conduits when subsurface access is required.

Practical Value:

• Ensures products have the structural strength to withstand field load conditions, when properly installed.
• Promotes cost-effective, efficient, and reliable installation through standardized component sizes and properties.
• Supports regulatory and municipal requirements for public infrastructure projects.
• Reduces risk of failure or excessive maintenance through clear acceptance, inspection, and repair provisions.

Related Standards

Professionals implementing ASTM C478/C478M-22 should also be familiar with these related standards:

• ASTM C33/C33M: Specification for Concrete Aggregates
• ASTM C39/C39M: Test Method for Compressive Strength of Cylindrical Concrete Specimens
• ASTM C150/C150M, C595/C595M: Specifications for different types of cement
• ASTM C260/C260M, C494/C494M: Specifications for admixtures in concrete
• ASTM A615/A615M, A706/A706M, A1064/A1064M: Specifications for steel reinforcement
• ASTM C497/C497M: Test Methods for Concrete Pipe, Box Sections, and Manhole Sections
• ACI 318: Building Code for Requirements for Reinforced Concrete

Conclusion

Complying with ASTM C478/C478M-22 ensures the use of high-quality precast reinforced concrete manhole sections, strengthening the reliability and safety of water, sewer, and utility networks. Adhering to this standard is crucial for achieving durable and standardized solutions in public infrastructure and utility projects.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: C478/C478M −22
Standard Specification for
Circular Precast Reinforced Concrete Manhole Sections
This standard is issued under the fixed designation C478/C478M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
PART I—GENERAL responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
1. Scope*
mine the applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accor-
1.1 This specification covers the manufacture and purchase
dance with internationally recognized principles on standard-
requirements of products used for the assembly and construc-
ization established in the Decision on Principles for the
tion of circular vertical precast reinforced concrete manholes
Development of International Standards, Guides and Recom-
and structures used in sewer, drainage, and water works.
mendations issued by the World Trade Organization Technical
1.2 Part I, Sections1–11, of this specification presents
Barriers to Trade (TBT) Committee.
general requirements and requirements that are common to
each precast concrete product covered by this specification.
2. Referenced Documents
1.3 Part II of this specification presents specific require-
2.1 ASTM Standards:
ments for each manhole product in the following sections:
A615/A615M Specification for Deformed and Plain Carbon-
Product Section Steel Bars for Concrete Reinforcement
Grade Rings 12
A706/A706M Specification for Deformed and Plain Low-
Flat Slab Tops 13
Alloy Steel Bars for Concrete Reinforcement
Risers and Conical Tops 14
Base Sections 15
A1064/A1064M Specification for Carbon-Steel Wire and
Steps and Ladders 16
Welded Wire Reinforcement, Plain and Deformed, for
NOTE 1—Future products will be included in Part II in a future revision
Concrete
of this specification.
C33/C33M Specification for Concrete Aggregates
1.4 The values stated in either inch pound or SI units are to C39/C39M Test Method for Compressive Strength of Cylin-
drical Concrete Specimens
be regarded separately as standard. The SI units are shown in
brackets. The values stated in each system may not be exact C150/C150M Specification for Portland Cement
C260/C260M Specification for Air-Entraining Admixtures
equivalents;therefore,eachsystemshallbeusedindependently
of the other. Combining values from the two systems may for Concrete
C309 Specification for Liquid Membrane-Forming Com-
result in nonconformance with the standard.
pounds for Curing Concrete
NOTE 2—This specification is a manufacturing and purchase specifica-
C494/C494M Specification for Chemical Admixtures for
tion only and does not include requirements for backfill, or the relation-
Concrete
ship between field load conditions and the strength requirements of the
manhole products and appurtenances. Experience has shown, however,
C497 Test Methods for Concrete Pipe, Concrete Box
that the successful performance of this product depends upon the proper
Sections, Manhole Sections, or Tile
selection of the product strength, type of foundation and backfill, and care
C497M Test Methods for Concrete Pipe, Concrete Box
in the field installation of the manhole products and connecting pipes.The
Sections, Manhole Sections, or Tile (Metric)
owner of the project for which these products are specified herein is
C595/C595M Specification for Blended Hydraulic Cements
cautioned to require inspection at the construction site.
C618 Specification for Coal Fly Ash and Raw or Calcined
1.5 This standard does not purport to address all of the
Natural Pozzolan for Use in Concrete
safety concerns, if any, associated with its use. It is the
C822 Terminology Relating to Concrete Pipe and Related
Products
This specification is under the jurisdiction of ASTM Committee C13 on
Concrete Pipe and is the direct responsibility of Subcommittee C13.06 on Manholes
and Specials. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Sept. 1, 2022. Published September 2022. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1961. Last previous edition approved in 2020 as C478/C478M – 20. Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/C0478_C0478M-22. the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C478/C478M − 22
C989/C989M Specification for Slag Cement for Use in 4.1.4 Aggregates—Aggregates shall conform to Specifica-
Concrete and Mortars tion C33/C33M, except that the requirements for gradation
C1017/C1017M Specification for Chemical Admixtures for shall not apply.
Use in Producing Flowing Concrete (Withdrawn 2022)
4.1.5 Admixtures—The following admixtures and blends are
C1116/C1116M Specification for Fiber-Reinforced Concrete
allowable:
C1602/C1602M Specification for Mixing Water Used in the
4.1.5.1 Air-entraining admixture conforming to Specifica-
Production of Hydraulic Cement Concrete
tion C260/C260M;
4.1.5.2 Chemical admixture conforming to Specification
2.2 ACI Standard:
C494/C494M;
318 Building Code, Requirements for Reinforced Concrete
4.1.5.3 Chemical admixture for use in producing flowing
concrete conforming to Specification C1017/C1017M;
3. Terminology
4.1.5.4 Chemical admixture or blend approved by the
3.1 Definitions—For definitions of terms relating to precast
owner.
reinforced concrete manholes, see Terminology C822.
4.1.6 Steel Reinforcement—Reinforcement shall consist of
wire and welded wire conforming to Specification A1064/
4. Materials and Manufacture
A1064M or of bars conforming to Specification A615/A615M,
4.1 General material requirements for precast reinforced
Grade 40 or 60, or Specification A706/A706M, Grade 60.
concretemanholeproductsarepresentedin4.1.1–4.1.9.Other
4.1.7 Water—Water used in the production of concrete shall
materials or additional requirements for a product, if any, are
be potable or non-potable water that meets the requirements of
covered in the Part II section for that specific product.
Specification C1602/C1602M.
4.1.1 Reinforced Concrete—Reinforced concrete shall con-
4.1.8 Fiber—Synthetic fibers and nonsynthetic fibers shall
sist of cementitious materials, mineral aggregates, admixtures,
beallowedtobeused,atthemanufacturer’soption,inconcrete
if used, and water, in which steel reinforcement has been
manholes as a nonstructural manufacturing material. Synthetic
embedded in such a manner so that the steel reinforcement and
fibers (Type II and Type III) and nonsynthetic fiber (Type 1)
concrete act together.
designed and manufactured specifically for use in concrete and
4.1.2 Cementitious Materials:
conforming to the requirements of Specification C1116/
4.1.2.1 Cement—Cement shall conform to the requirements
C1116M shall be accepted.
for portland cement of Specification C150/C150M, or shall be
4.1.9 Other Materials—Other materials required for a prod-
portland blast-furnace slag cement, portland-limestone cement,
uct and not covered in Section 4 will be covered in the Part II
or portland-pozzolan cement conforming to the requirements
section for that specific product.
of Specification C595/C595M, except that the pozzolan con-
stituent of the Type IP portland-pozzolan cement shall be fly
5. Design
ash.
4.1.2.2 Fly Ash—Fly ash shall conform to the requirements 5.1 Design requirements for a product are prescribed in the
of Class F or Class C of Specification C618. specific Part II section for that product.
4.1.2.3 Slag Cement—Slag cement shall conform to the
5.1.1 The minimum compressive strength of concrete man-
requirements of Grade 100 or 120 of Specification C989/
hole products covered by this specification shall be 4000 psi
C989M.
[27.6 MPa] unless specified otherwise in Part II of this
4.1.3 Allowable Combinations of Cementitious Materials— specification.
Thecombinationofcementitiousmaterialsusedintheconcrete
5.2 Modified or Special Design
shall be one of the following:
5.2.1 Manufacturers are not prohibited from submitting to
4.1.3.1 Portland cement only,
the owner, for approval prior to manufacture, designs other
4.1.3.2 Portland blast-furnace slag cement only,
than those prescribed in the specific section for a product. If
4.1.3.3 Portland-pozzolan cement only,
such approval is obtained, then the product shall meet all the
4.1.3.4 Portland-limestone cement only,
tests and performance requirements specified by the owner in
4.1.3.5 A combination of portland cement or portland-
accordance with the appropriate sections on manufacture and
limestone cement and slag cement,
physical requirements.
4.1.3.6 A combination of portland cement or portland-
5.2.1.1 If a modified or special design consists of require-
limestone cement, and fly ash, or
ments other than reinforcement that is specified for the
4.1.3.7 A combination of portland cement or portland-
manhole components within this standard, the written submit-
limestone cement, slag cement, and fly ash, or
tal shall include installed and handling structural analysis, past
4.1.3.8 A combination of portland-pozzolan cement and fly
product testing and recommended testing, and production
ash.
quality control processes to provide assurances the modified or
special design assumptions proposed are fully incorporated
with the furnished product.
The last approved version of this historical standard is referenced on
5.2.2 If permitted by the owner, the manufacturer is not
www.astm.org.
prohibited from requesting approval of designs of special
Available fromAmerican Concrete Institute (ACI), P.O. Box 9094, Farmington
Hills, MI 48333-9094, http://www.aci-int.org. sections, such as reducers, tees, and bases.
C478/C478M − 22
6. Reinforcement 7.2.1 Steam Curing—Concrete products are placed in a
curing chamber, free of outside drafts, and cured in a moist
6.1 This section presents requirements for reinforcement
atmosphere maintained by the injection of steam for such time
cover, continuity, laps, welds, and splices. Other reinforcement
andsuchtemperaturesasneededtoenabletheproductstomeet
requirements are presented in Section 4, and any additional
the strength requirements. The curing chamber shall be so
requirements are given in the Part II section for a specific
constructed as to allow full circulation of the steam around the
product.
entire product.
6.2 Cover—The exposure of the ends of reinforcement,
7.2.2 Water Curing—Concrete products are water-cured by
stirrups or spacers used to position the reinforcement during
covering with water-saturated material, or by a system of
placement of the concrete shall not be cause for rejection.
perforated pipes, mechanical sprinklers, porous hose, or by any
otherapprovedmethodthatwillkeeptheproductsmoistduring
6.3 Continuity—The continuity of the circumferential rein-
the curing period.
forcement shall not be destroyed during the manufacture of the
7.2.3 Sealing Membrane—Asealing membrane conforming
product, except when lift holes or pipe openings are provided
to the requirements of Specification C309 is applied and shall
in the product.
be left intact until the required concrete strength requirements
6.4 Welded Steel Cage Laps, Welds, and Splices:
are met. The concrete at the time of application of the
6.4.1 If splices are not welded, the reinforcement shall be
membrane shall be within 10°F [6°C] of the atmospheric
lapped not less than 20 diameters for deformed bars and
temperature. All concrete surfaces shall be kept moist prior to
deformed cold-worked wire, and 40 diameters for plain bars
the application of the membrane and shall be damp when the
and cold-worked wire. The measurement of this lap length
membrane is applied.
shall be tip-to-tip from the ends of the circumferential wires. In
7.2.4 The manufacturer is not prohibited from combining
addition, where lapped cages of welded wire reinforcement are
the methods prescribed in 7.2.1 – 7.2.3 provided the required
used without welding, the lap shall contain a longitudinal wire.
concrete compressive strength is attained.
6.4.2 When splices are welded and are not lapped to the
minimum requirements in 6.4.1, there shall be a minimum lap
8. Acceptance
of 2 in. [50 mm] and a weld of sufficient length such that pull
8.1 Acceptance Procedures:
tests of representative specimens shall develop at least 50 % of
8.1.1 Unless otherwise designated by the owner at the time
the minimum specified tensile strength of the steel. For butt
of, or before, placing an order, acceptance procedures for
welded splices in bars or wire, permitted only with helically
precast reinforced concrete manhole products shall be as
wound cages, pull tests of representative specimens shall
specifiedinthePartIIsectionforaparticularproduct,andshall
developatleast75 %oftheminimumspecifiedtensilestrength
not be prohibited from consisting of one or more of the
of the steel.
following:
6.5 Steel Hoop Splices—When splices are welded and are
8.1.1.1 Acceptance of a product on the basis of tests of
notlappedtotheminimumrequirementsin6.4.1,thereshallbe
materials, including concrete compressive strength and absorp-
a minimum lap of 2 in. [50 mm] and a weld of sufficient length
tion.
suchthatpulltestsfromrepresentativespecimensshalldevelop
8.1.1.2 Acceptanceofaproductonthebasisofinspectionof
at least 50 % of the minimum specified tensile strength of the
the finished product, including amount and placement of
steel. For butt welded splices, pull tests from representative
reinforcement to determine conformance with the design
specimens shall develop at least 75 % of the minimum speci-
prescribed under this specification, and freedom from defects.
fied tensile strength of the steel.
8.2 Test Methods:
8.2.1 Concrete Compressive Strength Test:
7. Precast Concrete Manufacture
8.2.1.1 Type of Specimen—Compression tests for satisfying
7.1 Mixture—The aggregates shall be sized, graded,
the minimum specified concrete strength requirement shall be
proportioned, and mixed with such proportions of cementitious
made on either concrete cylinders or, at the option of the
materials and water as will produce a thoroughly-mixed
manufacturer, on cores cut from the concrete manhole product.
concrete of such quality that the products will conform to the
8.2.1.2 Compression Testing of Cylinders—Cylinders shall
test and design requirements of this specification. All concrete
be made in accordance with Test Methods C497 [C497M], and
shall have a water-cementitious ratio not exceeding 0.53 by
shallbetestedinaccordancewithTestMethodC39/C39M.For
weight [mass]. Cementitious materials shall be as specified in
manhole products, an owner shall not be prohibited from
4.1.2andshallbeaddedtothemixinaproportionnotlessthan
requiring concrete compressive tests on cylinder specimens
3 3
470 lb/yd [280 kg/m ], unless mix designs with a lower
numberingintheamountof5 %ofthetotalorderofamanhole
cementitious materials content demonstrate that the quality and
product, but not to exceed two cylinders for each day’s
performance of the product meet the requirements of this
production. The average compressive strength of all cylinders
specification.
tested shall be equal to or greater than the specified strength of
7.2 Curing—Concrete products shall be subjected to any the concrete. Not more than 10 % of the cylinders tested shall
one of the methods of curing prescribed in 7.2.1 – 7.2.4 or to fall below the specified strength of the concrete. In no case
any other method or combination of methods approved by the shall any cylinder tested fall below 80 % of the specified
owner that will give satisfactory results. strength of the concrete.
C478/C478M − 22
8.2.1.3 Compression Testing of Cores—Cores shall be cut tests shall be made on the balance of the order and the products
from the concrete manhole product and tested in accordance shall be accepted if in conformance with the requirements of
with Test Methods C497 [C497M], except that the require- this specification.
ments for moisture conditioning shall not apply. One core shall
8.3 Test Equipment—Every manufacturer furnishing man-
be taken from a manhole product selected at random from each
hole products under this specification shall furnish all facilities
day’s production run of a single concrete strength. When the
and personnel necessary to carry out the tests required for
concrete compressive strength of the core is equal to or greater
acceptance.
than80 %ofthespecifiedstrengthoftheconcrete,theconcrete
strength of the production run is acceptable. If the core does 9. Repairs
not meet the preceding concrete strength requirement, another
9.1 Repair of manhole products shall not be prohibited, if
core from the same manhole product shall be taken and tested.
necessary, because of imperfections in manufacture or damage
8.2.1.4 If the concrete compressive strength of the recore is
during handling, and will be acceptable if, in the opinion of the
equal to or greater than 80 % of the specified strength of the
owner, the repaired products conform to the requirements of
concrete, the concrete strength of the production run is accept-
this specification.
able. If the recore does not meet the preceding concrete
10. Inspection
strength requirement, that manhole product shall be rejected.
Two manhole products from the remainder of the day’s
10.1 The quality of materials, the process of manufacture,
production run shall be selected at random and one core taken
and the finished manhole products shall be subject to inspec-
from each manhole product and tested. When the average
tion and approval by the owner. The method of marking as to
concrete strength of the two cores is equal to or greater than
acceptanceorrejectionofthemanholeproductsshallbeagreed
80 % of the specified strength of the concrete with no core
upon, prior to inspection, between the owner and the manu-
below 75 % of the specified strength of the concrete, the
facturer.
concrete strength of the day’s production run shall be accept-
11. Product Marking
able.
8.2.1.5 If the concrete strength of the two cores does not
11.1 The following information shall be legibly marked on
meet the preceding concrete strength requirement, then the
each precast concrete product:
remainder of the day’s production run shall be either rejected,
11.1.1 Specification and product designation: MH for man-
or, at the option of the manufacturer, each manhole product of
hole base, riser, conical tops, and grade rings,
the remainder of the day’s production run is not prohibited
11.1.2 Date of manufacture, and
from being cored and accepted individually.
11.1.3 Name or trademark of the manufacturer.
8.2.1.6 Plugging Core Holes—Core holes on accepted con-
11.2 Marking shall be indented into the concrete or shall be
crete manhole products shall be plugged and sealed by the
painted thereon with waterproof paint.
manufacturer in a manner such that the manhole products will
PART II—PRODUCTS
meet all of the requirements of this specification. Manhole
sections so sealed shall be considered as satisfactory for use.
12. Grade Rings
8.2.2 Absorption Test:
12.1 Scope—This section covers precast reinforced concrete
8.2.2.1 The absorption of a specimen from a concrete
grade rings used for final adjustment of manholes to grade.
product, as determined in Test Methods C497 [C497M], shall
not exceed 9 % of the dry mass for Test Method A procedure 12.2 Acceptance—Acceptability of grade rings covered by
or 8.5 % for Test Method B procedure. All specimens shall be this specification shall be determined by the results of such
tests of materials as are required by Section 4; by compressive
free of visible cracks and shall represent the full thickness of
the product. strength tests on concrete cores or concrete cylinders required
by Section 8; and by inspection of the finished product,
8.2.2.2 SpecimensforTestMethodBshallmeettherequire-
including amount and placement of reinforcement as pre-
ments of Test Methods C497 [C497M].
scribed by 12.4, 12.5, and 12.6, to determine its conformance
8.2.2.3 Each specimen tested by Test MethodAshall have a
with the design prescribed under this specification and its
minimum weight of 2.2 lbs [1.0 kg].
freedom from defects.
8.2.2.4 When the initial absorption specimen from a con-
12.3 Design—The minimum wall thickness shall be one
crete product fails to conform to this specification, the absorp-
twelfth of the internal diameter of the grade ring or 4 in. [100
tion test shall be made on another specimen from the same
mm], whichever is greater.
product and the results of the retest shall be substituted for the
12.3.1 Joints—Grade rings are not required to have the joint
original test results.
formed with male and female ends.
8.2.3 Retests—When not more than 20 % of the concrete
test specimens tested under either 8.2.2.1 or 8.2.2.2 fail to pass 12.4 Circumferential Reinforcement:
the requirements of this specification, the manufacturer is not 12.4.1 The circumferential reinforcement shall have an
prohibited from culling his stock and eliminating whatever equivalent area of not less than 0.07 in. /vertical ft [15
2 2 2
quantity of product he desires and shall so mark the culled mm /vertical m], but not less than 0.024 in. [15 mm]inany
productthattheywillnotbeshippedfortheorder.Therequired one grade ring.
C478/C478M − 22
12.4.2 The circumferential reinforcement shall be one line 13.2.1 Acceptability of flat slab tops shall be determined by
in the center third of the wall of the grade ring. the results of such tests of materials as are required by Section
4; by compressive strength tests on concrete cores or concrete
12.5 Permissible Variations:
cylinders required by Section 8; and by inspection of the
12.5.1 Internal Diameter—The internal diameter of grade
finishedproduct,includingamountandplacementofreinforce-
rings shall not vary more than 61%.
ment as prescribed by 13.4 and 13.6, to determine its confor-
12.5.2 Wall Thickness—The wall thickness of grade rings
mance with the design prescribed under this specification and
shall be not less than that prescribed in the design by more than
its freedom from defects.
5% or 6 ⁄16 in. [65 mm], whichever is greater. A wall
13.2.2 Unless otherwise designated by the owner at the time
thickness greater than that prescribed in the design shall not be
of, or before, placing an order, two separate and alternative
cause for rejection.
methods of acceptance are permitted for flat slab top manufac-
12.5.3 Height of Two Opposite Sides—Variations in laying
turer designs, in addition to tests of materials and inspection
height of two opposite sides of grade rings shall be not more
required in 13.2.1.
than ⁄4 in. [6 mm].
13.2.2.1 Acceptance on the Basis of Proof-of-Design Test—
12.5.4 Height of Grade Ring—The underrun in height of a
1 Acceptance of flat slab tops on the basis of the results of a
grade ring shall be not more than ⁄8 in./ft [10 mm/m] of height.
proof-of-design test performed in accordance with 13.5 in lieu
12.5.5 Position of Reinforcement—For grade rings with a
of submission of design calculations and detailed drawings.
4-in. [100 mm] wall thickness, the maximum variation in the
13.2.2.2 Acceptance on the Basis of Rational Design—
design position of circumferential reinforcement from that
Acceptance of flat slab tops on the basis of design calculations
described in 12.4.1 shall be 610 % of the wall thickness or
by a rational method and detailed drawings.
6 ⁄4 in. [66 mm], whichever is greater. For grade rings with a
wall thickness greater than 4 in. [100 mm], the maximum
13.3 Design:
variation from the design position of reinforcement shall be
13.3.1 The basis of flat slab top designs shall be the
610 % of the wall thickness or 6 ⁄8 in. [616 mm], whichever
appropriate sections of the latest edition of ACI 318.
is the lesser. In no case, however, shall the cover over the
13.3.2 Flatslabtopsshallhaveaminimumthicknessof6in.
reinforcement be less than ⁄4 in. [19 mm]. The preceding
[150 mm] for risers up to and including 48 in. [1200 mm] in
minimum cover limitation does not apply to the mating
diameter and 8 in. [200 mm] for larger diameters.
surfaces of the joint.
13.3.3 The flat slab top access opening shall be a minimum
12.5.6 Area of Reinforcement—Steel reinforcement areas
2 2 of 24 in. [600 mm] in diameter.
that are 0.005 in. /linear ft [10 mm /linear m] less than called
13.3.4 Joint—The reinforced concrete flat slab top shall be
for by design shall be considered as meeting the required steel
formed with or without a male or female end so that when the
reinforcement area.
manhole base, riser and top section are assembled, they will
12.6 Rejection:
make a continuous and uniform manhole compatible with the
12.6.1 Grade rings shall be subject to rejection for failure to
tolerances given in 13.6.
conform to any of the specification requirements. In addition,
13.3.4.1 Joints are designed to perform in axial compres-
an individual grade ring shall be subject to rejection because of
sion; therefore, shear or load testing of the joint is not required.
any of the following:
13.4 Reinforcement:
12.6.1.1 Fractures or cracks passing through the wall, ex-
ceptforasingleendcrackthatdoesnotexceedthedepthofthe 13.4.1 Flat slab tops manufactured with a joint or with other
joint. indication of the top or bottom of the slab shall be manufac-
12.6.1.2 Defects that indicate mixing and molding not in tured with one layer of reinforcement placed near the bottom
surfacesothattheprotectivecoveroverthereinforcementshall
compliance with 7.1 or surface defects indicating honey-
be 1 in. [25 mm].
combed or open texture that would adversely affect the
function of the grade ring. 13.4.2 Flat slab tops manufactured without a joint or with-
12.6.1.3 The planes of the ends are not perpendicular to the
out other indication of the top or bottom of the slab shall be
longitudinal axis of the grade ring, within the limits of manufactured with two layers of steel reinforcement, one
permissible variations prescribed in 12.5.
located near the bottom surface and one near the top surface so
12.6.1.4 Damaged or cracked ends, where such damage that the protective cover over each layer is 1 in. [25 mm].
would prevent making a satisfactory joint.
13.4.3 A layer of reinforcement shall have a minimum area
2 2
12.6.1.5 Any continuous crack having a surface wid
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: C478/C478M − 20 C478/C478M − 22
Standard Specification for
Circular Precast Reinforced Concrete Manhole Sections
This standard is issued under the fixed designation C478/C478M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
PART I—GENERAL
1. Scope*
1.1 This specification covers the manufacture and purchase requirements of products used for the assembly and construction of
circular vertical precast reinforced concrete manholes and structures used in sewer, drainage, and water works.
1.2 Part I, Sections 1 – 11, of this specification presents general requirements and requirements that are common to each precast
concrete product covered by this specification.
1.3 Part II of this specification presents specific requirements for each manhole product in the following sections:
Product Section
Grade Rings 12
Flat Slab Tops 13
Risers and Conical Tops 14
Base Sections 15
Steps and Ladders 16
NOTE 1—Future products will be included in Part II in a future revision of this specification.
1.4 The values stated in either inch pound or SI units are to be regarded separately as standard. The SI units are shown in brackets.
The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other.
Combining values from the two systems may result in nonconformance with the standard.
NOTE 2—This specification is a manufacturing and purchase specification only and does not include requirements for backfill, or the relationship between
field load conditions and the strength requirements of the manhole products and appurtenances. Experience has shown, however, that the successful
performance of this product depends upon the proper selection of the product strength, type of foundation and backfill, and care in the field installation
of the manhole products and connecting pipes. The owner of the project for which these products are specified herein is cautioned to require inspection
at the construction site.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
This specification is under the jurisdiction of ASTM Committee C13 on Concrete Pipe and is the direct responsibility of Subcommittee C13.06 on Manholes and Specials.
Current edition approved Sept. 1, 2020Sept. 1, 2022. Published September 2020September 2022. Originally approved in 1961. Last previous edition approved in 20192020
as C478 – 19.C478/C478M – 20. DOI: 10.1520/C0478_C0478M-20.10.1520/C0478_C0478M-22.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C478/C478M − 22
1.6 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
A615/A615M Specification for Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement
A706/A706M Specification for Deformed and Plain Low-Alloy Steel Bars for Concrete Reinforcement
A1064/A1064M Specification for Carbon-Steel Wire and Welded Wire Reinforcement, Plain and Deformed, for Concrete
C33/C33M Specification for Concrete Aggregates
C39/C39M Test Method for Compressive Strength of Cylindrical Concrete Specimens
C150/C150M Specification for Portland Cement
C260/C260M Specification for Air-Entraining Admixtures for Concrete
C309 Specification for Liquid Membrane-Forming Compounds for Curing Concrete
C494/C494M Specification for Chemical Admixtures for Concrete
C497 Test Methods for Concrete Pipe, Concrete Box Sections, Manhole Sections, or Tile
C497M Test Methods for Concrete Pipe, Concrete Box Sections, Manhole Sections, or Tile (Metric)
C595/C595M Specification for Blended Hydraulic Cements
C618 Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete
C822 Terminology Relating to Concrete Pipe and Related Products
C989/C989M Specification for Slag Cement for Use in Concrete and Mortars
C1017/C1017M Specification for Chemical Admixtures for Use in Producing Flowing Concrete (Withdrawn 2022)
C1116/C1116M Specification for Fiber-Reinforced Concrete
C1602/C1602M Specification for Mixing Water Used in the Production of Hydraulic Cement Concrete
2.2 ACI Standard:
318 Building Code, Requirements for Reinforced Concrete
3. Terminology
3.1 Definitions—For definitions of terms relating to precast reinforced concrete manholes, see Terminology C822.
4. Materials and Manufacture
4.1 General material requirements for precast reinforced concrete manhole products are presented in 4.1.1 – 4.1.9. Other materials
or additional requirements for a product, if any, are covered in the Part II section for that specific product.
4.1.1 Reinforced Concrete—Reinforced concrete shall consist of cementitious materials, mineral aggregates, admixtures, if used,
and water, in which steel reinforcement has been embedded in such a manner so that the steel reinforcement and concrete act
together.
4.1.2 Cementitious Materials:
4.1.2.1 Cement—Cement shall conform to the requirements for portland cement of Specification C150/C150M, or shall be
portland blast-furnace slag cement, portland-limestone cement, or portland-pozzolan cement conforming to the requirements of
Specification C595/C595M, except that the pozzolan constituent of the Type IP portland-pozzolan cement shall be fly ash.
4.1.2.2 Fly Ash—Fly ash shall conform to the requirements of Class F or Class C of Specification C618.
4.1.2.3 Slag Cement—Slag cement shall conform to the requirements of Grade 100 or 120 of Specification C989/C989M.
4.1.3 Allowable Combinations of Cementitious Materials—The combination of cementitious materials used in the concrete shall
be one of the following:
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
Available from American Concrete Institute (ACI), P.O. Box 9094, Farmington Hills, MI 48333-9094, http://www.aci-int.org.
C478/C478M − 22
4.1.3.1 Portland cement only,
4.1.3.2 Portland blast-furnace slag cement only,
4.1.3.3 Portland-pozzolan cement only,
4.1.3.4 Portland-limestone cement only,
4.1.3.5 A combination of portland cement or portland-limestone cement and slag cement,
4.1.3.6 A combination of portland cement or portland-limestone cement, and fly ash, or
4.1.3.7 A combination of portland cement or portland-limestone cement, slag cement, and fly ash, or
4.1.3.8 A combination of portland-pozzolan cement and fly ash.
4.1.4 Aggregates—Aggregates shall conform to Specification C33/C33M, except that the requirements for gradation shall not
apply.
4.1.5 Admixtures—The following admixtures and blends are allowable:
4.1.5.1 Air-entraining admixture conforming to Specification C260/C260M;
4.1.5.2 Chemical admixture conforming to Specification C494/C494M;
4.1.5.3 Chemical admixture for use in producing flowing concrete conforming to Specification C1017/C1017M;
4.1.5.4 Chemical admixture or blend approved by the owner.
4.1.6 Steel Reinforcement—Reinforcement shall consist of wire and welded wire conforming to Specification A1064/A1064M or
of bars conforming to Specification A615/A615M, Grade 40 or 60, or Specification A706/A706M, Grade 60.
4.1.7 Water—Water used in the production of concrete shall be potable or non-potable water that meets the requirements of
Specification C1602/C1602M.
4.1.8 Fiber—Synthetic fibers and nonsynthetic fibers shall be allowed to be used, at the manufacturer’s option, in concrete
manholes as a nonstructural manufacturing material. Synthetic fibers (Type II and Type III) and nonsynthetic fiber (Type 1)
designed and manufactured specifically for use in concrete and conforming to the requirements of Specification C1116/C1116M
shall be accepted.
4.1.9 Other Materials—Other materials required for a product and not covered in Section 4 will be covered in the Part II section
for that specific product.
5. Design
5.1 Design requirements for a product are prescribed in the specific Part II section for that product.
5.1.1 The minimum compressive strength of concrete manhole products covered by this specification shall be 4000 psi [27.6 MPa]
unless specified otherwise in Part II of this specification.
5.2 Modified or Special Design
5.2.1 Manufacturers are not prohibited from submitting to the owner, for approval prior to manufacture, designs other than those
prescribed in the specific section for a product. If such approval is obtained, then the product shall meet all the tests and
performance requirements specified by the owner in accordance with the appropriate sections on manufacture and physical
requirements.
C478/C478M − 22
5.2.1.1 If a modified or special design consists of requirements other than reinforcement that is specified for the manhole
components within this standard, the written submittal shall include installed and handling structural analysis, past product testing
and recommended testing, and production quality control processes to provide assurances the modified or special design
assumptions proposed are fully incorporated with the furnished product.
5.2.2 If permitted by the owner, the manufacturer is not prohibited from requesting approval of designs of special sections, such
as reducers, tees, and bases.
6. Reinforcement
6.1 This section presents requirements for reinforcement cover, continuity, laps, welds, and splices. Other reinforcement
requirements are presented in Section 4, and any additional requirements are given in the Part II section for a specific product.
6.2 Cover—The exposure of the ends of reinforcement, stirrups or spacers used to position the reinforcement during placement
of the concrete shall not be cause for rejection.
6.3 Continuity—The continuity of the circumferential reinforcement shall not be destroyed during the manufacture of the product,
except when lift holes or pipe openings are provided in the product.
6.4 Welded Steel Cage Laps, Welds, and Splices:
6.4.1 If splices are not welded, the reinforcement shall be lapped not less than 20 diameters for deformed bars, and bars and
deformed cold-worked wire, and 40 diameters for plain bars and cold-drawn wire. cold-worked wire. The measurement of this lap
length shall be tip-to-tip from the ends of the circumferential wires. In addition, where lapped cages of welded wire
fabricreinforcement are used without welding, the lap shall contain a longitudinal wire.
6.4.2 When splices are welded and are not lapped to the minimum requirements in 6.4.1, there shall be a minimum lap of 2 in.
[50 mm] and a weld of sufficient length such that pull tests of representative specimens shall develop at least 50 % of the minimum
specified tensile strength of the steel. For butt welded splices in bars or wire, permitted only with helically wound cages, pull tests
of representative specimens shall develop at least 75 % of the minimum specified tensile strength of the steel.
6.5 Steel Hoop Splices—When splices are welded and are not lapped to the minimum requirements in 6.4.1, there shall be a
minimum lap of 2 in. [50 mm] and a weld of sufficient length such that pull tests from representative specimens shall develop at
least 50 % of the minimum specified tensile strength of the steel. For butt welded splices, pull tests from representative specimens
shall develop at least 75 % of the minimum specified tensile strength of the steel.
7. Precast Concrete Manufacture
7.1 Mixture—The aggregates shall be sized, graded, proportioned, and mixed with such proportions of cementitious materials and
water as will produce a thoroughly-mixed concrete of such quality that the products will conform to the test and design
requirements of this specification. All concrete shall have a water-cementitious ratio not exceeding 0.53 by weight [mass].
Cementitious materials shall be as specified in 4.1.2 and shall be added to the mix in a proportion not less than 470 lb/yd [280
kg/m ], unless mix designs with a lower cementitious materials content demonstrate that the quality and performance of the
product meet the requirements of this specification.
7.2 Curing—Concrete products shall be subjected to any one of the methods of curing prescribed in 7.2.1 – 7.2.4 or to any other
method or combination of methods approved by the owner that will give satisfactory results.
7.2.1 Steam Curing—Concrete products are placed in a curing chamber, free of outside drafts, and cured in a moist atmosphere
maintained by the injection of steam for such time and such temperatures as needed to enable the products to meet the strength
requirements. The curing chamber shall be so constructed as to allow full circulation of the steam around the entire product.
7.2.2 Water Curing—Concrete products are water-cured by covering with water-saturated material, or by a system of perforated
pipes, mechanical sprinklers, porous hose, or by any other approved method that will keep the products moist during the curing
period.
C478/C478M − 22
7.2.3 Sealing Membrane—A sealing membrane conforming to the requirements of Specification C309 is applied and shall be left
intact until the required concrete strength requirements are met. The concrete at the time of application of the membrane shall be
within 10°F [6°C] of the atmospheric temperature. All concrete surfaces shall be kept moist prior to the application of the
membrane and shall be damp when the membrane is applied.
7.2.4 The manufacturer is not prohibited from combining the methods prescribed in 7.2.1 – 7.2.3 provided the required concrete
compressive strength is attained.
8. Acceptance
8.1 Acceptance Procedures:
8.1.1 Unless otherwise designated by the owner at the time of, or before, placing an order, acceptance procedures for precast
reinforced concrete manhole products shall be as specified in the Part II section for a particular product, and shall not be prohibited
from consisting of one or more of the following:
8.1.1.1 Acceptance of a product on the basis of tests of materials, including concrete compressive strength and absorption.
8.1.1.2 Acceptance of a product on the basis of inspection of the finished product, including amount and placement of
reinforcement to determine conformance with the design prescribed under this specification, and freedom from defects.
8.2 Test Methods:
8.2.1 Concrete Compressive Strength Test:
8.2.1.1 Type of Specimen—Compression tests for satisfying the minimum specified concrete strength requirement shall be made
on either concrete cylinders or, at the option of the manufacturer, on cores cut from the concrete manhole product.
8.2.1.2 Compression Testing of Cylinders—Cylinders shall be made in accordance with Test Methods C497 [C497M], and shall
be tested in accordance with Test Method C39/C39M. For manhole products, an owner shall not be prohibited from requiring
concrete compressive tests on cylinder specimens numbering in the amount of 5 % of the total order of a manhole product, but
not to exceed two cylinders for each day’s production. The average compressive strength of all cylinders tested shall be equal to
or greater than the specified strength of the concrete. Not more than 10 % of the cylinders tested shall fall below the specified
strength of the concrete. In no case shall any cylinder tested fall below 80 % of the specified strength of the concrete.
8.2.1.3 Compression Testing of Cores—Cores shall be cut from the concrete manhole product and tested in accordance with Test
Methods C497 [C497M], except that the requirements for moisture conditioning shall not apply. One core shall be taken from a
manhole product selected at random from each day’s production run of a single concrete strength. When the concrete compressive
strength of the core is equal to or greater than 80 % of the specified strength of the concrete, the concrete strength of the production
run is acceptable. If the core does not meet the preceding concrete strength requirement, another core from the same manhole
product shall be taken and tested.
8.2.1.4 If the concrete compressive strength of the recore is equal to or greater than 80 % of the specified strength of the concrete,
the concrete strength of the production run is acceptable. If the recore does not meet the preceding concrete strength requirement,
that manhole product shall be rejected. Two manhole products from the remainder of the day’s production run shall be selected
at random and one core taken from each manhole product and tested. When the average concrete strength of the two cores is equal
to or greater than 80 % of the specified strength of the concrete with no core below 75 % of the specified strength of the concrete,
the concrete strength of the day’s production run shall be acceptable.
8.2.1.5 If the concrete strength of the two cores does not meet the preceding concrete strength requirement, then the remainder
of the day’s production run shall be either rejected, or, at the option of the manufacturer, each manhole product of the remainder
of the day’s production run is not prohibited from being cored and accepted individually.
8.2.1.6 Plugging Core Holes—Core holes on accepted concrete manhole products shall be plugged and sealed by the manufacturer
in a manner such that the manhole products will meet all of the requirements of this specification. Manhole sections so sealed shall
be considered as satisfactory for use.
C478/C478M − 22
8.2.2 Absorption Test:
8.2.2.1 The absorption of a specimen from a concrete product, as determined in Test Methods C497 [C497M], shall not exceed
9 % of the dry mass for Test Method A procedure or 8.5 % for Test Method B procedure. All specimens shall be free of visible
cracks and shall represent the full thickness of the product.
8.2.2.2 Specimens for Test Method B shall meet the requirements of Test Methods C497 [C497M].
8.2.2.3 Each specimen tested by Test Method A shall have a minimum weight of 2.2 lbs [1.0 kg].
8.2.2.4 When the initial absorption specimen from a concrete product fails to conform to this specification, the absorption test shall
be made on another specimen from the same product and the results of the retest shall be substituted for the original test results.
8.2.3 Retests—When not more than 20 % of the concrete test specimens tested under either 8.2.2.1 or 8.2.2.2 fail to pass the
requirements of this specification, the manufacturer is not prohibited from culling his stock and eliminating whatever quantity of
product he desires and shall so mark the culled product that they will not be shipped for the order. The required tests shall be made
on the balance of the order and the products shall be accepted if in conformance with the requirements of this specification.
8.3 Test Equipment—Every manufacturer furnishing manhole products under this specification shall furnish all facilities and
personnel necessary to carry out the tests required for acceptance.
9. Repairs
9.1 Repair of manhole products shall not be prohibited, if necessary, because of imperfections in manufacture or damage during
handling, and will be acceptable if, in the opinion of the owner, the repaired products conform to the requirements of this
specification.
10. Inspection
10.1 The quality of materials, the process of manufacture, and the finished manhole products shall be subject to inspection and
approval by the owner. The method of marking as to acceptance or rejection of the manhole products shall be agreed upon, prior
to inspection, between the owner and the manufacturer.
11. Product Marking
11.1 The following information shall be legibly marked on each precast concrete product:
11.1.1 Specification and product designation: MH for manhole base, riser, conical tops, and grade rings,
11.1.2 Date of manufacture, and
11.1.3 Name or trademark of the manufacturer.
11.2 Marking shall be indented into the concrete or shall be painted thereon with waterproof paint.
PART II—PRODUCTS
12. Grade Rings
12.1 Scope—This section covers precast reinforced concrete grade rings used for final adjustment of manholes to grade.
12.2 Acceptance—Acceptability of grade rings covered by this specification shall be determined by the results of such tests of
materials as are required by Section 4; by compressive strength tests on concrete cores or concrete cylinders required by Section
8; and by inspection of the finished product, including amount and placement of reinforcement as prescribed by 12.4, 12.5, and
12.6, to determine its conformance with the design prescribed under this specification and its freedom from defects.
C478/C478M − 22
12.3 Design—The minimum wall thickness shall be one twelfth of the internal diameter of the grade ring or 4 in. [100 mm],
whichever is greater.
12.3.1 Joints—Grade rings are not required to have the joint formed with male and female ends.
12.4 Circumferential Reinforcement:
2 2
12.4.1 The circumferential reinforcement shall have an equivalent area of not less than 0.07 in. /vertical ft [15 mm /vertical m],
2 2
but not less than 0.024 in. [15 mm ] in any one grade ring.
12.4.2 The circumferential reinforcement shall be one line in the center third of the wall of the grade ring.
12.5 Permissible Variations:
12.5.1 Internal Diameter—The internal diameter of grade rings shall not vary more than 6 1 %.
12.5.2 Wall Thickness—The wall thickness of grade rings shall be not less than that prescribed in the design by more than 5 %
or 6 ⁄16 in. [65 mm], whichever is greater. A wall thickness greater than that prescribed in the design shall not be cause for
rejection.
12.5.3 Height of Two Opposite Sides—Variations in laying height of two opposite sides of grade rings shall be not more than ⁄4
in. [6 mm].
12.5.4 Height of Grade Ring—The underrun in height of a grade ring shall be not more than ⁄8 in./ft [10 mm/m] of height.
12.5.5 Position of Reinforcement—For grade rings with a 4-in. [100 mm] wall thickness, the maximum variation in the design
position of circumferential reinforcement from that described in 12.4.1 shall be 610 % of the wall thickness or 6 ⁄4 in. [66 mm],
whichever is greater. For grade rings with a wall thickness greater than 4 in. [100 mm], the maximum variation from the design
position of reinforcement shall be 610 % of the wall thickness or 6 ⁄8 in. [616 mm], whichever is the lesser. In no case, however,
shall the cover over the reinforcement be less than ⁄4 in. [19 mm]. The preceding minimum cover limitation does not apply to the
mating surfaces of the joint.
2 2
12.5.6 Area of Reinforcement—Steel reinforcement areas that are 0.005 in. /linear ft [10 mm /linear m] less than called for by
design shall be considered as meeting the required steel reinforcement area.
12.6 Rejection:
12.6.1 Grade rings shall be subject to rejection for failure to conform to any of the specification requirements. In addition, an
individual grade ring shall be subject to rejection because of any of the following:
12.6.1.1 Fractures or cracks passing through the wall, except for a single end crack that does not exceed the depth of the joint.
12.6.1.2 Defects that indicate mixing and molding not in compliance with 7.1 or surface defects indicating honeycombed or open
texture that would adversely affect the function of the grade ring.
12.6.1.3 The planes of the ends are not perpendicular to the longitudinal axis of the grade ring, within the limits of permissible
variations prescribed in 12.5.
12.6.1.4 Damaged or cracked ends, where such damage would prevent making a satisfactory joint.
12.6.1.5 Any continuous crack having a surface width of 0.01 in. [0.3 mm] or more and extending for a length of 12 in. [300 m]
or more, regardless of position in the wall.
C478/C478M − 22
13. Flat Slab Tops
13.1 Scope—This section covers precast reinforced concrete flat slab tops used in the construction of manholes for use in sewer,
drainage, and water works.
13.2 Acceptance:
13.2.1 Acceptability of flat slab tops shall be determined by the results of such tests of materials as are required by Section 4; by
compressive strength tests on concrete cores or concrete cylinders required by Section 8; and by inspection of the finished product,
including amount and placement of reinforcement as prescribed by 13.4 and 13.6, to determine its conformance with the design
prescribed under this specification and its freedom from defects.
13.2.2 Unless otherwise designated by the owner at the time of, or before, placing an order, two separate and alternative methods
of acceptance are permitted for flat slab top manufacturer designs, in addition to tests of materials and inspection required in 13.2.1.
13.2.2.1 Acceptance on the Basis of Proof-of-Design Test—Acceptance of flat slab tops on the basis of the results of a
proof-of-design test performed in accordance with 13.5 in lieu of submission of design calculations and detailed drawings.
13.2.2.2 Acceptance on the Basis of Rational Design—Acceptance of flat slab tops on the basis of design calculations by a rational
method and detailed drawings.
13.3 Design:
13.3.1 The basis of flat slab top designs shall be the appropriate sections of the latest edition of ACI 318.
13.3.2 Flat slab tops shall have a minimum thickness of 6 in. [150 mm] for risers up to and including 48 in. [1200 mm] in diameter
and 8 in. [200 mm] for larger diameters.
13.3.3 The flat slab top access opening shall be a minimum of 24 in. [600 mm] in diameter.
13.3.4 Joint—The reinforced concrete flat slab top shall be formed with or without a male or female end so that when the manhole
base, riser and top section are assembled, they will make a continuous and uniform manhole compatible with the tolerances given
in 13.6.
13.3.4.1 Joints are designed to perform in axial compression; therefore, shear or load testing of the joint is not required.
13.4 Reinforcement:
13.4.1 Flat slab tops manufactured with a joint or with other indication of the top or bottom of the slab shall be manufactured with
one layer of reinforcement placed near the bottom surface so that the protective cover over the reinforcement s
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