ASTM C1227-23

Standard Specification for Precast Concrete Septic Tanks

ABSTRACT
This specification covers monolithicor sectional precast concrete septic tanks. The following materials shall be used for manufacturing concrete septic tank: cement, aggregates, water, admixtures, steel reinforcement, concrete mixtures, forms, concrete placement, fibers, and sealants. The precast concrete sections shall be cured. Structural design of the septic tanks shall be by calculation or by performance. Concrete strength, reinforcing steel placement, and openings shall also be considered in the design. The physical design requirements include: capacity, shape, compartments, influent and effluent pipes, baffles and outlet devices, and openings in top slab. The following tests shall also be done: proof testing, leakage testing, vacuum testing, and water-pressure testing.
SCOPE
1.1 This specification covers design requirements, manufacturing practices, and performance requirements for monolithic or sectional precast concrete septic tanks.  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.3 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.  
1.4 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-Jul-2023
• ICS: 13.060.30 - Sewage water
• Technical Committee: C27 - Precast Concrete Products
• Drafting Committee: C27.30 - Water and Wastewater Containers

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 C94/C94M-24a - Standard Specification for Ready-Mixed Concrete
• Effective Date: 01-Apr-2024
• Refers: ASTM C94/C94M-24 - Standard Specification for Ready-Mixed Concrete
• Effective Date: 01-Jan-2024
• Refers: ASTM C231/C231M-24 - Standard Test Method for Air Content of Freshly Mixed Concrete by the Pressure Method
• Effective Date: 01-Jan-2024
• Refers: ASTM C39/C39M-23 - Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens
• Effective Date: 01-Dec-2023
• Refers: ASTM C125-19a - Standard Terminology Relating to Concrete and Concrete Aggregates
• Effective Date: 15-Dec-2019
• Refers: ASTM C990-09(2019) - Standard Specification for Joints for Concrete Pipe, Manholes, and Precast Box Sections Using Preformed Flexible Joint Sealants
• Effective Date: 01-Sep-2019
• Refers: ASTM C94/C94M-19 - Standard Specification for Ready-Mixed Concrete
• Effective Date: 01-Jul-2019
• Refers: ASTM C150/C150M-19 - Standard Specification for Portland Cement
• Effective Date: 01-Apr-2019
• Refers: ASTM C125-19 - Standard Terminology Relating to Concrete and Concrete Aggregates
• 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 C125-18b - Standard Terminology Relating to Concrete and Concrete Aggregates
• Effective Date: 01-Oct-2018
• Refers: ASTM C125-18a - Standard Terminology Relating to Concrete and Concrete Aggregates
• Effective Date: 01-Jul-2018
• Refers: ASTM C125-18 - Standard Terminology Relating to Concrete and Concrete Aggregates
• Effective Date: 01-Jan-2018
• Refers: ASTM C1644-06(2017) - Standard Specification for Resilient Connectors Between Reinforced Concrete On-Site Wastewater Tanks and Pipes
• Effective Date: 01-Nov-2017

Overview

ASTM C1227-23: Standard Specification for Precast Concrete Septic Tanks is a widely recognized international standard published by ASTM International. The specification sets forth comprehensive requirements for the design, manufacture, and performance of both monolithic and sectional precast concrete septic tanks. These tanks play a critical role in on-site wastewater treatment systems, particularly for residential and light commercial installations. The standard promotes quality, durability, and safety by standardizing manufacturing processes and physical attributes, as well as performance and testing criteria.

Key Topics

• Materials and Manufacture

  • Specifies use of portland cement, aggregates, water, admixtures, steel reinforcement, and fibers conforming to relevant ASTM standards.
  • Allows for flexible sealants and connectors ensuring watertightness.
  • Requires thorough curing and consistent concrete quality, including minimum compressive strength.

• Structural and Physical Design

  • Design to be determined by calculation (following ACI 318 principles) or by physical performance testing.
  • Considers critical factors such as concrete strength, reinforcement placement, openings, and structural loads (earth, water, and live loads).
  • Physical requirements address minimum tank capacity, compartment configuration, pipe connections, baffles, outlet devices, and access openings.

• Dimensional Tolerances and Marking

  • Prescribes limits for permissible variations in length, width, height, and squareness for manufactured tanks.
  • Requires tanks to be clearly marked with manufacturing information, capacity, and design load criteria.

• Testing and Quality Control

  • Proof tests, leakage tests (vacuum or water pressure), and random sampling ensure structural integrity and watertightness.
  • Manufacturers must certify compliance with dimensional, strength, and watertightness requirements.

Applications

ASTM C1227-23 is used as a reference by designers, manufacturers, installers, and regulators across the wastewater treatment industry. Key practical applications include:

• Residential and Light Commercial Wastewater Treatment

  • Ensures precast concrete septic tanks meet structural and operational demands for single-family houses, multi-unit residences, office buildings, restaurants, and hotels.
  • Satisfies regulatory requirements for tank size and construction, supporting building code compliance.

• Quality Assurance for Precast Products

  • Provides manufacturers with standardized criteria for raw materials, production processes, and end-product testing, aiding in the production of reliable and durable tanks.
  • Supports purchasers and regulators in specifying, reviewing, and accepting compliant tanks for installation.

• Public Health and Environmental Protection

  • Promotes effective anaerobic digestion and safe containment of sanitary waste, lowering risks of contamination and system failure.
  • Encourages proper marking and warnings on tanks to improve safety during installation and maintenance.

Related Standards

To ensure comprehensive compliance and compatibility, the following related standards are frequently referenced in conjunction with ASTM C1227-23:

• ASTM C33/C33M: Specification for Concrete Aggregates
• ASTM C150/C150M: Specification for Portland Cement
• ASTM A615/A615M: Specification for Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement
• ACI 318: Building Code Requirements for Reinforced Concrete
• ASTM C990: Specification for Joints for Concrete Pipe, Manholes, and Precast Box Sections Using Preformed Flexible Joint Sealants
• NSF/ANSI 46: Evaluation of Components and Devices Used in Wastewater Treatment Systems

By aligning with ASTM C1227-23 and its referenced standards, stakeholders ensure that precast concrete septic tanks are fit for purpose, delivering long-term performance, reliability, and safety in wastewater management systems.

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: C1227 − 23
Standard Specification for
Precast Concrete Septic Tanks
This standard is issued under the fixed designation C1227; 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.
1. Scope drical Concrete Specimens
C94/C94M Specification for Ready-Mixed Concrete
1.1 This specification covers design requirements, manufac-
C125 Terminology Relating to Concrete and Concrete Ag-
turing practices, and performance requirements for monolithic
gregates
or sectional precast concrete septic tanks.
C150/C150M Specification for Portland Cement
1.2 The values stated in inch-pound units are to be regarded
C231/C231M Test Method for Air Content of Freshly Mixed
as standard. The values given in parentheses are mathematical
Concrete by the Pressure Method
conversions to SI units that are provided for information only
C260/C260M Specification for Air-Entraining Admixtures
and are not considered standard.
for Concrete
1.3 This standard does not purport to address all of the C330/C330M Specification for Lightweight Aggregates for
safety concerns, if any, associated with its use. It is the
Structural Concrete
responsibility of the user of this standard to establish appro- C494/C494M Specification for Chemical Admixtures for
priate safety, health, and environmental practices and deter-
Concrete
mine the applicability of regulatory limitations prior to use. C595/C595M Specification for Blended Hydraulic Cements
1.4 This international standard was developed in accor-
C618 Specification for Coal Ash and Raw or Calcined
dance with internationally recognized principles on standard- Natural Pozzolan for Use in Concrete
ization established in the Decision on Principles for the
C685/C685M Specification for Concrete Made by Volumet-
Development of International Standards, Guides and Recom- ric Batching and Continuous Mixing
mendations issued by the World Trade Organization Technical
C890 Practice for Minimum Structural Design Loading for
Barriers to Trade (TBT) Committee. Monolithic or Sectional Precast Concrete Water and
Wastewater Structures
2. Referenced Documents
C990 Specification for Joints for Concrete Pipe, Manholes,
and Precast Box Sections Using Preformed Flexible Joint
2.1 ASTM Standards:
Sealants
A1064/A1064M Specification for Carbon-Steel Wire and
C1116/C1116M Specification for Fiber-Reinforced Concrete
Welded Wire Reinforcement, Plain and Deformed, for
C1157/C1157M Performance Specification for Hydraulic
Concrete
Cement
A615/A615M Specification for Deformed and Plain Carbon-
C1644 Specification for Resilient Connectors Between Re-
Steel Bars for Concrete Reinforcement
inforced Concrete On-Site Wastewater Tanks and Pipes
A706/A706M Specification for Deformed and Plain Low-
2.2 ACI Standard:
Alloy Steel Bars for Concrete Reinforcement
ACI 318 Building Code Requirements for Reinforced Con-
A996/A996M Specification for Rail-Steel and Axle-Steel
crete
Deformed Bars for Concrete Reinforcement
2.3 NSF/ANSI Standard:
C33/C33M Specification for Concrete Aggregates
C39/C39M Test Method for Compressive Strength of Cylin- NSF/ANSI 46–2005 Evaluation of Components and Devices
used in Wastewater Treatment Systems
3. Terminology
This specification is under the jurisdiction of ASTM Committee C27 on Precast
Concrete Products and is the direct responsibility of Subcommittee C27.30 on Water
3.1 For definitions of terms relating to concrete, see Termi-
and Wastewater Containers.
nology C125.
Current edition approved Aug. 1, 2023. Published August 2023. Originally
approved in 1993. Last previous edition approved in 2022 as C1227 – 22. DOI:
10.1520/C1227-23.
2 3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Available from American Concrete Institute (ACI), P.O. Box 9094, Farmington
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Hills, MI 48333-9094, http://www.aci-int.org.
Standards volume information, refer to the standard’s Document Summary page on Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
the ASTM website. 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1227 − 23
3.2 Definitions of Terms Specific to This Standard: 3.2.20 rated volume, n—depth from the bottom of a septic
tank to the invert of the outlet pipe.
3.2.1 access opening, n—hole in the top slab used to gain
access to the inside of the tank for the purpose of cleaning and
3.2.21 scum layer, n—buoyant waste floating near the sur-
removing sludge without a person actually having to enter the
face of liquid, consisting of lighter-than-water materials, such
tank.
as greases and soaps.
3.2.2 air scum volume, n—number of cubic inches (centi-
3.2.22 sealed joint, n—joint that is sealed to prevent liquid
meters) in the space between the liquid surface and the
passing from one side of a precast concrete wall to the opposite
underside of the top slab.
side.
3.2.3 baffle, n—device placed in a tank to dissipate energy, 3.2.23 septic tank system, n—anaerobic digestion chamber
direct flow, retain solids, and/or draw liquid off at a specific
in which domestic sewage is received and retained, and from
depth. which the liquid effluent, which is comparatively free from
settleable and floating solids, is then discharged.
3.2.4 baffle, inlet, n—tee or wall segment at or near the inlet
pipe of a tank designed to direct flow below the liquid surface. 3.2.24 sludge layer, n—heavier waste solids that separate
and settle at the bottom of a tank.
3.2.5 baffle, outlet, n—tee or wall segment at or near the
3.2.25 tee, n—“T”-shaped pipe fitting made of corrosion-
outlet pipe of a tank designed to collect flow from the liquid
resistant materials used to connect horizontal piping with
effluent layer.
vertical piping and used to provide access for cleaning piping.
3.2.6 cement, n—powdered substance of lime and clay
mixed with water to make concrete.
4. Ordering Information
3.2.7 connector, n—device that provides a flexible seal
4.1 The purchaser shall include the following information in
between a pipe and the precast concrete tank.
bidding documents and on the purchase order, as applicable to
3.2.8 corrosion-resistant, adj—materials that are resistant to
the units being ordered:
deterioration when in contact with the corrosive materials
4.1.1 Reference to this specification and date of issue.
found in a septic tank.
4.1.2 Quantity, that is, number of units ordered.
4.1.3 Capacity of tank in gallons or liters.
3.2.9 dead load, n—mass of a structure and all permanent
loads imposed on the structure (that is, soil). 4.1.4 Special cement requirements including moderate
sulfate-resisting cement, Specification C150/C150M Type II,
3.2.10 detention time, n—average length of time a unit
or highly sulfate-resisting cement, Specification C150/C150M,
volume of liquid or a suspended particle remains in a tank;
Type V. If the purchaser does not stipulate, the manufacturer
mathematically, it is the volume of liquid in the tank divided by
shall use any cement meeting the requirements of Specification
the flow rate through the tank.
C150/C150M, C595/C595M, or C1157/C1157M.
3.2.11 effective volume, n—maximum amount of liquid and
4.1.5 Acceptance will be based on a review of the calcula-
solids that can be contained in a tank under normal operating
tions or on proof tests.
conditions.
4.1.6 Design requirements such as depth of earth cover, live
load applied at the surface, and ground water level.
3.2.12 effluent filter device, n—device, made from
corrosion-resistant materials, that separates solid material from 4.1.7 Testing for water leakage shall not be required at the
tank liquid before the liquid exits the tank. job site unless specifically required by the purchaser.
4.1.8 Manufacturer is permitted to require testing on site
3.2.13 grinder, n—device for grinding and flushing cooking
prior to backfill.
wastes; also known as a garbage disposal.
3.2.14 inspection opening, n—hole in the top slab used for
5. Materials and Manufacture
the purpose of observing conditions inside the tank.
5.1 Cement—Portland cement shall conform to the require-
3.2.15 joint, n—physical separation where two pieces of
ments of Specification C150/C150M, C595/C595M, or C1157/
precast concrete are in contact.
C1157M.
3.2.16 liquid effluent layer, n—area in a tank made up of
5.2 Aggregates—Aggregates shall conform to Specification
liquids and semibuoyant waste particles after the sludge and
C33/C33M and lightweight aggregates shall conform to Speci-
scum waste have separated and settled.
fication C330/C330M, except that the requirements for grading
3.2.17 live load, n—loads exerted on or above a structure shall not apply.
when the source of the load is dynamic and transient.
5.3 Water—Water used in mixing concrete shall be clean
3.2.18 non-sealed joint, n—joint in which sealant is not used and free of injurious amounts of oils, acids, alkalies, salts,
but in which a machined fit will minimize the movement of organic materials, or other substances that will be incompatible
liquid from one side of a precast concrete wall to the opposite with concrete or steel.
side.
5.4 Admixtures—Admixtures, when used, shall conform to
3.2.19 owner, n—is by definition, end user, customer, or Specification C494/C494M or Specification C618 and shall not
purchaser. be injurious to other products used in the concrete.
C1227 − 23
5.4.1 Air-Entraining Admixtures—Air-entraining admix- 6. Structural Design Requirements
tures conforming to Specification C260/C260M shall be used
6.1 Structural design of septic tanks shall be by calculation
when there is a risk that the concrete will be exposed to
or by performance.
freezing and thawing. Then the concrete mixture shall contain
6.1.1 Design by Calculation—The method of structural
5.5 6 1.5 % air by volume as determined by Test Method
design of reinforced concrete as outlined in the ACI 318
C231/C231M.
Building Code shall be used to design the concrete sections,
including the reinforcement required, when the structure is
5.5 Steel Reinforcement—Steel reinforcement shall conform
to Specification A1064/A1064M for wire fabric, or Specifica- subjected to the loading conditions covered in Practice C890.
Design requirements in excess of these specifications shall be
tions A615/A615M, A706/A706M, or A996/A996M for steel
reinforcement bars. identified by the purchaser.
6.1.2 Design by Performance—Design by performance re-
5.5.1 Locating Reinforcement—Reinforcement shall be
quires the manufacturer to demonstrate that failure will not
placed in the forms as required by the design.
occur by physically applying loads to the product. The load
5.5.2 Holding Reinforcement in Position During Pouring
applied shall be 1.5 times the anticipated actual loads.
Placement—Reinforcement shall be securely held in place by
6.1.3 Tanks shall be designed so that they will not collapse
tying, clipping, or welding to maintain position during concrete
or rupture when subjected to anticipated earth and hydrostatic
placing operations. Welding procedures shall conform to the
pressures when the tanks are either full or empty.
appropriate material specification. Chairs, bolsters, braces, and
6.1.4 The structural design of tanks will consider buoyancy
spacers in contact with forms shall have a corrosion-resistant
effects, if applicable, and proportion the structure to ensure an
surface.
adequate flotation safety factor.
5.6 Concrete Mixtures—The aggregates, cement, and water
6.1.5 All dead and live loads shall be considered in the
shall be proportioned and mixed to produce a homogeneous
design. For tanks located in residential lawn areas and not
concrete meeting the requirements of this specification, and in
subject to loads greater than the minimum stated herein, the
accordance with Specification C94/C94M or Specification 2
minimum live load shall be 100 lbf/ft (5 kPa) or a concen-
C685/C685M. The concrete shall have a maximum water
trated load of 2250 lbs (10 kN) applied to a 10 by 10 in. (250
cementitious materials ratio of 0.45.
by 250 mm) area, which ever produces the greatest stress on
5.7 Forms—The forms used in manufacture shall be suffi- the structure. Concentrated loads shall be distributed in accor-
ciently rigid and accurate to maintain the dimensions of the dance with provisions of Practice C890. Loading conditions
structure within the stated tolerances. All casting surfaces shall other than described herein shall conform with provision of
be of smooth nonporous material. Form releasing agents used Practice C890.
shall not be injurious to the concrete. 6.1.6 The live loads imposed at lifting points shall be
considered in the design of the structure.
5.8 Concrete Placement—Concrete shall be placed in the
6.1.7 Inserts embedded in the concrete shall be designed for
forms at a rate to allow the concrete to consolidate in all parts
an ultimate load that is four times the working load (Factor of
of the form, and around all reinforcement steel and embedded
Safety = 4).
fixtures without segregation of materials.
6.2 Concrete Strength—The minimum compressive strength
5.9 Curing—The precast concrete sections shall be cured by
(f'c) for designs shall be 4000 psi (28 MPa) at 28 days of age.
any method or combination of methods that will develop the
6.3 Reinforcing Steel Placement—The concrete cover for
specified compressive strength at 28 days or less.
reinforcing bars, mats, or fabric shall not be less than 1 in. (25
5.10 Concrete Quality—The quality of the concrete shall be
mm).
in accordance with the chapter on concrete quality in ACI 318,
6.4 Openings—The structural design shal
...

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: C1227 − 22 C1227 − 23
Standard Specification for
Precast Concrete Septic Tanks
This standard is issued under the fixed designation C1227; 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.
1. Scope
1.1 This specification covers design requirements, manufacturing practices, and performance requirements for monolithic or
sectional precast concrete septic tanks.
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
1.3 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.
1.4 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:
A1064/A1064M Specification for Carbon-Steel Wire and Welded Wire Reinforcement, Plain and Deformed, for Concrete
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
A996/A996M Specification for Rail-Steel and Axle-Steel Deformed Bars for Concrete Reinforcement
C33/C33M Specification for Concrete Aggregates
C39/C39M Test Method for Compressive Strength of Cylindrical Concrete Specimens
C94/C94M Specification for Ready-Mixed Concrete
C125 Terminology Relating to Concrete and Concrete Aggregates
C150/C150M Specification for Portland Cement
C231/C231M Test Method for Air Content of Freshly Mixed Concrete by the Pressure Method
C260/C260M Specification for Air-Entraining Admixtures for Concrete
C330/C330M Specification for Lightweight Aggregates for Structural Concrete
C494/C494M Specification for Chemical Admixtures for Concrete
C595/C595M Specification for Blended Hydraulic Cements
C618 Specification for Coal Ash and Raw or Calcined Natural Pozzolan for Use in Concrete
C685/C685M Specification for Concrete Made by Volumetric Batching and Continuous Mixing
This specification is under the jurisdiction of ASTM Committee C27 on Precast Concrete Products and is the direct responsibility of Subcommittee C27.30 on Water
and Wastewater Containers.
Current edition approved June 1, 2022Aug. 1, 2023. Published June 2022August 2023. Originally approved in 1993. Last previous edition approved in 20202022 as
C1227 – 20.C1227 – 22. DOI: 10.1520/C1227-22.10.1520/C1227-23.
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.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1227 − 23
C890 Practice for Minimum Structural Design Loading for Monolithic or Sectional Precast Concrete Water and Wastewater
Structures
C990 Specification for Joints for Concrete Pipe, Manholes, and Precast Box Sections Using Preformed Flexible Joint Sealants
C1116/C1116M Specification for Fiber-Reinforced Concrete
C1157/C1157M Performance Specification for Hydraulic Cement
C1644 Specification for Resilient Connectors Between Reinforced Concrete On-Site Wastewater Tanks and Pipes
2.2 ACI Standard:
ACI 318 Building Code Requirements for Reinforced Concrete
2.3 NSF/ANSI Standard:
NSF/ANSI 46–2005 Evaluation of Components and Devices used in Wastewater Treatment Systems
3. Terminology
3.1 For definitions of terms relating to concrete, see Terminology C125.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 access opening, n—hole in the top slab used to gain access to the inside of the tank for the purpose of cleaning and removing
sludge without a person actually having to enter the tank.
3.2.2 air scum volume, n—number of cubic inches (centimeters) in the space between the liquid surface and the underside of the
top slab.
3.2.3 baffle, n—device placed in a tank to dissipate energy, direct flow, retain solids, and/or draw liquid off at a specific depth.
3.2.4 baffle, inlet, n—tee or wall segment at or near the inlet pipe of a tank designed to direct flow below the liquid surface.
3.2.5 baffle, outlet, n—tee or wall segment at or near the outlet pipe of a tank designed to collect flow from the liquid effluent layer.
3.2.6 cement, n—powdered substance of lime and clay mixed with water to make concrete.
3.2.7 connector, n—device that provides a flexible seal between a pipe and the precast concrete tank.
3.2.8 corrosion-resistant, adj—materials that are resistant to deterioration when in contact with the corrosive materials found in
a septic tank.
3.2.9 dead load, n—mass of a structure and all permanent loads imposed on the structure (that is, soil).
3.2.10 detention time, n—average length of time a unit volume of liquid or a suspended particle remains in a tank; mathematically,
it is the volume of liquid in the tank divided by the flow rate through the tank.
3.2.11 effective volume, n—maximum amount of liquid and solids that can be contained in a tank under normal operating
conditions.
3.2.12 effluent filter device, n—device, made from corrosion-resistant materials, that separates solid material from tank liquid
before the liquid exits the tank.
3.2.13 grinder, n—device for grinding and flushing cooking wastes; also known as a garbage disposal.
3.2.14 inspection opening, n—hole in the top slab used for the purpose of observing conditions inside the tank.
3.2.15 joint, n—physical separation where two pieces of precast concrete are in contact.
Available from American Concrete Institute (ACI), P.O. Box 9094, Farmington Hills, MI 48333-9094, http://www.aci-int.org.
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
C1227 − 23
3.2.16 liquid effluent layer, n—area in a tank made up of liquids and semibuoyant waste particles after the sludge and scum waste
have separated and settled.
3.2.17 live load, n—loads exerted on or above a structure when the source of the load is dynamic and transient.
3.2.18 non-sealed joint, n—joint in which sealant is not used but in which a machined fit will minimize the movement of liquid
from one side of a precast concrete wall to the opposite side.
3.2.19 owner, n—is by definition, end user, customer, or purchaser.
3.2.20 rated volume, n—depth from the bottom of a septic tank to the invert of the outlet pipe.
3.2.21 scum layer, n—buoyant waste floating near the surface of liquid, consisting of lighter-than-water materials, such as greases
and soaps.
3.2.22 sealed joint, n—joint that is sealed to prevent liquid passing from one side of a precast concrete wall to the opposite side.
3.2.23 septic tank system, n—anaerobic digestion chamber in which domestic sewage is received and retained, and from which
the liquid effluent, which is comparatively free from settleable and floating solids, is then discharged.
3.2.24 sludge layer, n—heavier waste solids that separate and settle at the bottom of a tank.
3.2.25 tee, n—“T”-shaped pipe fitting made of corrosion-resistant materials used to connect horizontal piping with vertical piping
and used to provide access for cleaning piping.
4. Ordering Information
4.1 The purchaser shall include the following information in bidding documents and on the purchase order, as applicable to the
units being ordered:
4.1.1 Reference to this specification and date of issue.
4.1.2 Quantity, that is, number of units ordered.
4.1.3 Capacity of tank in gallons or liters.
4.1.4 Special cement requirements including moderate sulfate-resisting cement, Specification C150/C150M Type II, or highly
sulfate-resisting cement, Specification C150/C150M, Type V. If the purchaser does not stipulate, the manufacturer shall use any
cement meeting the requirements of Specification C150/C150M, C595/C595Mor , or C595/C595MC1157/C1157M.
4.1.5 Acceptance will be based on a review of the calculations or on proof tests.
4.1.6 Design requirements such as depth of earth cover, live load applied at the surface, and ground water level.
4.1.7 Testing for water leakage shall not be required at the job site unless specifically required by the purchaser.
4.1.8 Manufacturer is permitted to require testing on site prior to backfill.
5. Materials and Manufacture
5.1 Cement—Portland cement shall conform to the requirements of Specification C150/C150M, C595/C595Mor shall be portland
blast-furnace slag cement or portland-pozzolan cement conforming to the requirements of Specification , or C595/C595MC1157/
C1157M.
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5.2 Aggregates—Aggregates shall conform to Specification C33/C33M and lightweight aggregates shall conform to Specification
C330/C330M, except that the requirements for grading shall not apply.
5.3 Water—Water used in mixing concrete shall be clean and free of injurious amounts of oils, acids, alkalies, salts, organic
materials, or other substances that will be incompatible with concrete or steel.
5.4 Admixtures—Admixtures, when used, shall conform to Specification C494/C494M or Specification C618 and shall not be
injurious to other products used in the concrete.
5.4.1 Air-Entraining Admixtures—Air-entraining admixtures conforming to Specification C260/C260M shall be used when there
is a risk that the concrete will be exposed to freezing and thawing. Then the concrete mixture shall contain 5.5 6 1.5 % air by
volume as determined by Test Method C231/C231M.
5.5 Steel Reinforcement—Steel reinforcement shall conform to Specification A1064/A1064M for wire fabric, or Specifications
A615/A615M, A706/A706M, or A996/A996M for steel reinforcement bars.
5.5.1 Locating Reinforcement—Reinforcement shall be placed in the forms as required by the design.
5.5.2 Holding Reinforcement in Position During Pouring Placement—Reinforcement shall be securely held in place by tying,
clipping, or welding to maintain position during concrete placing operations. Welding procedures shall conform to the appropriate
material specification. Chairs, bolsters, braces, and spacers in contact with forms shall have a corrosion-resistant surface.
5.6 Concrete Mixtures—The aggregates, cement, and water shall be proportioned and mixed to produce a homogeneous concrete
meeting the requirements of this specification, and in accordance with Specification C94/C94M or Specification C685/C685M. The
concrete shall have a maximum water cementitious materials ratio of 0.45.
5.7 Forms—The forms used in manufacture shall be sufficiently rigid and accurate to maintain the dimensions of the structure
within the stated tolerances. All casting surfaces shall be of smooth nonporous material. Form releasing agents used shall not be
injurious to the concrete.
5.8 Concrete Placement—Concrete shall be placed in the forms at a rate to allow the concrete to consolidate in all parts of the
form, and around all reinforcement steel and embedded fixtures without segregation of materials.
5.9 Curing—The precast concrete sections shall be cured by any method or combination of methods that will develop the specified
compressive strength at 28 days or less.
5.10 Concrete Quality—The quality of the concrete shall be in accordance with the chapter on concrete quality in ACI 318, except
for frequency of tests, which shall be specified by the purchaser. Concrete compressive strength tests shall be conducted in
accordance with Test Method C39/C39M.
5.11 Fibers—Polypropylene, polyolefin, or glass fibers are only permitted as a secondary reinforcing material, at the
manufacturer’s option, in precast concrete septic tanks. For the purposes of this specification, secondary reinforcing material is
only used to resist temperature and shrinkage effects. Only Type II or III conforming to the requirements of Specification
C1116/C1116M shall be accepted.
5.12 Sealants—Flexible sealants used in the manufacture and installation of tanks shall conform to Specification C990. Rigid
(mortar) sealing of tank sections is not permitted.
5.13 Pipe Connections—Pipe-to-tank connections shall use flexible connectors conforming to the requirements of Specification
C1644.
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6. Structural Design Requirements
6.1 Structural design of septic tanks shall be by calculation or by performance.
6.1.1 Design by Calculation—Design by calculation shall be completed using the Strength Design Method (ultimate strength
theory) or the Alternate Design Method (working stress theory) outlined in ACI 318.The method of structural design of reinforced
concrete as outlined in the ACI 318 Building Code shall be used to design the concrete sections, including the reinforcement
required, when the structure is subjected to the loading conditions covered in Practice C890The Strength Design Method is outlined
in Chapter 9 and the Alternate Design Method is in Appendix A. Design requirements in excess of these specifications shall be
identified by the purchaser.
6.1.2 Design by Performance—Design by performance requires the manufacturer to demonstrate that failure will not occur by
physically applying loads to the product. The load applied shall be 1.5 times the anticipated actual loads.
6.1.3 Tanks shall be designed so that they will not collapse or rupture when subjected to anticipated earth and hydrostatic pressures
when the tanks are either full or empty.
6.1.4 The structural design of tanks will consider buoyancy effects, if applicable, and proportion the structure to ensure an
adequate fl
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