ASTM C1893-24

Standard Practice for Laboratory Performance Verification of Hydrodynamic Separators for the Treatment of Stormwater Runoff

SIGNIFICANCE AND USE
4.1 This practice provides criteria for the verification of the silica sediment removal efficiency of hydrodynamic separators.  
4.2 Verification can be used to support certification of the technology within different AHJs provided that:  
4.2.1 HDS units are sized using the resulting performance data to treat the prescribed water quality flow rate or annual mass load requirement at the level of performance desired by the certifying entity.  
4.2.2 Scaling of results to different MTD model sizes is in accordance with this standard.  
4.2.3 The technology is designed consistently with the tested unit such that it operates within the specified limits determined by the verification as well as other restrictions placed by the certification entity.
SCOPE
1.1 This practice covers the criteria for the laboratory verification of Hydrodynamic Separators (HDS) as it relates to the removal of suspended solids in stormwater runoff.  
1.2 HDS manufactured treatment devices are placed as offline or online treatment devices along storm drain pipe lines to remove suspended solids and associated pollutants from stormwater runoff. These devices may be used to target removal of other pollutants which are not covered in this standard. The criteria in this standard specifically relate to the removal of silica particles in controlled laboratory conditions, which is considered an appropriate surrogate for predicting the removal of stormwater solids from actual stormwater runoff.  
1.3 This practice provides guidelines for independent regulatory entities, collectively referred to as Authority Having Jurisdictions (AHJs), to streamline data requirements for the certification of HDS devices within their jurisdiction. For any given AHJ, additional criteria may also apply.  
1.4 Units—The values stated in inch-pound units are to be regarded as standard, except for methods to establish and report sediment concentration and particle size. It is convention to exclusively describe sediment concentration in mg/L and particle size in mm or μm, both of which are SI units. The SI units given in parentheses are mathematical conversions, which are provided for information purposes only and are not considered standard. Reporting of test results in units other than inch-pound units shall not be regarded as non-conformance with this test method.  
1.5 Acceptance of test results attained according to this specification may be subject to specific requirements set by a Quality Assurance Project Plan (QAPP), a specific verification protocol, or AHJ. It is advised to review one or all of the above to ensure compliance.  
1.6 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.
Note 1: This practice is also intended to ensure that the data resulting from completion of testing in accordance with the ASTM test methods referenced herein can be utilized to satisfy the requirements of the New Jersey Department of Environmental Protection’s manufactured treatment device (MTD) certification process.  
1.7 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: 29-Feb-2024
• ICS: 13.060.10 - Water of natural resources
• ICS: 71.040.10 - Chemical laboratories. Laboratory equipment
• Technical Committee: E64 - Stormwater Control Measures
• Drafting Committee: E64.01 - Lab Evaluation

Relations

• Replaces: ASTM C1893-23 - Standard Practice for Laboratory Performance Verification of Hydrodynamic Separators for the Treatment of Stormwater Runoff
• Effective Date: 01-Mar-2024

Overview

ASTM C1893-24 is the Standard Practice for Laboratory Performance Verification of Hydrodynamic Separators for the Treatment of Stormwater Runoff. Developed by ASTM International, this standard provides comprehensive criteria for the laboratory testing, verification, and performance evaluation of hydrodynamic separators (HDS) specifically regarding the removal of suspended solids from stormwater runoff. The document is essential for certifying the effectiveness of HDS devices as stormwater control measures and streamlining regulatory acceptance by various authorities having jurisdiction (AHJs).

Key Topics

• Laboratory Verification for Sediment Removal: Focuses on verifying HDS performance in removing suspended solids, particularly silica particles, under controlled laboratory conditions. Silica is used as a surrogate for broader stormwater solids, ensuring results are relevant for field applications.
• Certification and Regulatory Support: Provides data requirements and reporting protocols for HDS devices to support certification by regulatory entities (AHJs). Ensures uniformity when submitting devices for recognition across multiple jurisdictions.
• Performance Testing Criteria:
  • Full-scale, commercially available HDS units must be tested.
  • Assessments include system hydraulics, sediment removal efficiency, and scour susceptibility over a range of flows.
  • Verification requires the presence of an independent, qualified third-party observer and the use of accredited laboratories for all analytical testing.
  • Scaling guidance for application to different HDS unit sizes, ensuring results are transferable when devices are geometrically proportional.
• Reporting and Documentation: Specifies detailed reporting requirements, including significant digits, verification of data by independent parties, and mandatory performance claims.
• Units of Measure: Clear conventions for reporting area, flow rate, sediment concentration, velocity, and volume with both inch-pound and SI units allowed.

Applications

ASTM C1893-24 serves several critical applications in stormwater management:

• Stormwater Treatment Design: Enables engineers, manufacturers, and designers to validate that HDS units effectively remove suspended sediments before installation along storm drain pipelines, both as offline and online solutions.
• Regulatory Compliance: Provides a recognized laboratory protocol supporting device certification processes, such as those used by the New Jersey Department of Environmental Protection (NJDEP), and can be referenced by municipalities or state agencies adopting or adapting similar regulatory frameworks.
• Technology Certification: Streamlines data submission for manufacturers seeking certification or approval within various jurisdictions, supporting consistent assessment of manufactured treatment devices (MTDs).
• Product Development and Quality Assurance: Assures stakeholders that HDS devices have undergone rigorous, standardized testing overseen by independent, qualified personnel following precise protocols for sampling, analysis, and reporting.

Related Standards

Several ASTM standards and external protocols are referenced to ensure robust laboratory testing and consistent evaluations:

• ASTM C1745/C1745M - Measurement of Hydraulic Characteristics of Hydrodynamic Stormwater Separators
• ASTM C1746/C1746M - Measurement of Suspended Sediment Removal Efficiency
• ASTM D3977 - Determining Sediment Concentration in Water Samples
• ASTM D4959 - Determination of Water Content of Soil by Direct Heating
• ASTM D6913/D6913M / D7928 - Particle-Size Distribution of Soils
• ASTM E29 - Use of Significant Digits in Test Data
• ASTM E3317 - Specification for Silica-Based Sediments in Evaluation of Stormwater Treatment Devices
• ASTM E3373 - Test Method for Scour in Hydrodynamic Separators
• ASTM E3318 - Terminology for Stormwater Control Measures
• NJDEP Laboratory Protocols and Verification Procedures (for state-specific certification processes)

Practical Value

Implementing ASTM C1893-24 provides assurance of hydrodynamic separator performance, streamlines certification, and supports best practices in environmental engineering for stormwater quality improvement. Adhering to this standard allows for regulatory acceptance, improved product reliability, and scientifically sound data supporting the deployment of effective stormwater control measures.

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: C1893 − 24
Standard Practice for
Laboratory Performance Verification of Hydrodynamic
Separators for the Treatment of Stormwater Runoff
This standard is issued under the fixed designation C1893; 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 responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
1.1 This practice covers the criteria for the laboratory
mine the applicability of regulatory limitations prior to use.
verification of Hydrodynamic Separators (HDS) as it relates to
the removal of suspended solids in stormwater runoff.
NOTE 1—This practice is also intended to ensure that the data resulting
from completion of testing in accordance with the ASTM test methods
1.2 HDS manufactured treatment devices are placed as
referenced herein can be utilized to satisfy the requirements of the New
offline or online treatment devices along storm drain pipe lines
Jersey Department of Environmental Protection’s manufactured treatment
to remove suspended solids and associated pollutants from device (MTD) certification process.
stormwater runoff. These devices may be used to target
1.7 This international standard was developed in accor-
removal of other pollutants which are not covered in this
dance with internationally recognized principles on standard-
standard. The criteria in this standard specifically relate to the
ization established in the Decision on Principles for the
removal of silica particles in controlled laboratory conditions,
Development of International Standards, Guides and Recom-
which is considered an appropriate surrogate for predicting the
mendations issued by the World Trade Organization Technical
removal of stormwater solids from actual stormwater runoff.
Barriers to Trade (TBT) Committee.
1.3 This practice provides guidelines for independent regu-
2. Referenced Documents
latory entities, collectively referred to as Authority Having
Jurisdictions (AHJs), to streamline data requirements for the 2.1 ASTM Standards:
C1745/C1745M Test Method for Measurement of Hydraulic
certification of HDS devices within their jurisdiction. For any
given AHJ, additional criteria may also apply. Characteristics of Hydrodynamic Stormwater Separators
and Underground Settling Devices
1.4 Units—The values stated in inch-pound units are to be
C1746/C1746M Test Method for Measurement of Sus-
regarded as standard, except for methods to establish and
pended Sediment Removal Efficiency of Hydrodynamic
report sediment concentration and particle size. It is convention
Stormwater Separators and Underground Settling Devices
to exclusively describe sediment concentration in mg/L and
D3977 Test Methods for Determining Sediment Concentra-
particle size in mm or μm, both of which are SI units. The SI
tion in Water Samples
units given in parentheses are mathematical conversions,
D4959 Test Method for Determination of Water Content of
which are provided for information purposes only and are not
Soil By Direct Heating
considered standard. Reporting of test results in units other
D6913/D6913M Test Methods for Particle-Size Distribution
than inch-pound units shall not be regarded as non-
(Gradation) of Soils Using Sieve Analysis
conformance with this test method.
D7928 Test Method for Particle-Size Distribution (Grada-
1.5 Acceptance of test results attained according to this
tion) of Fine-Grained Soils Using the Sedimentation
specification may be subject to specific requirements set by a
(Hydrometer) Analysis
Quality Assurance Project Plan (QAPP), a specific verification
E29 Practice for Using Significant Digits in Test Data to
protocol, or AHJ. It is advised to review one or all of the above
Determine Conformance with Specifications
to ensure compliance.
E3317 Specification for Silica-Based Sediments for the
1.6 This standard does not purport to address all of the Evaluation of Stormwater Treatment Devices
safety concerns, if any, associated with its use. It is the E3318 Terminology for Standards Relating to Stormwater
Control Measures
This practice is under the jurisdiction of ASTM Committee E64 on Stormwater
Control Measures and is the direct responsibility of Subcommittee E64.01 on Lab
Evaluation. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved March 1, 2024. Published March 2024. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 2023. Last previous edition approved in 2023 as C1893 - 23. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/C1893-24. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1893 − 24
E3373 Test Method for Scour of Hydrodynamic Separators design and setup, sampling methods, handling, sample security
and Settling Devices (that is, chain of custody), task documentation, and data
management.
2.2 Additional References:
5.2.3 Relevant Experiences—Consulting or academic
New Jersey Department of Environmental Protection Labo-
(reporting, general laboratory practices).
ratory Protocol to Assess Total Suspended Solids Removal
by a Hydrodynamic Sedimentation Manufactured Treat-
5.3 Expectations for Third Party Observer—The third party
ment Device” January 1, 2021
observer shall witness all active aspects of testing carried out at
NJDEP Laboratory Test Protocols and Verification Proce-
a manufacturers facility as described herein as well as any
dure: NJCAT Interpretations”, NJDEP, August 4, 2021
supplemental test runs, measurements, sampling and analysis:
5.3.1 Observe and document the preparation and collection
3. Terminology
of test sediment samples for PSD analysis, background sus-
3.1 Definitions:
pended sediment concentration (SSC) samples, and effluent
3.1.1 For definitions of common technical terms used in this
SSC scour test sediment samples.
standard, refer to Terminology E3318.
5.3.2 Document test setup, including key dimensions, such
as, pipe sizes including diameter, slopes, and condition, hopper
4. Significance and Use
location and height, false floor elevation, location of sediment
injection point, and sediment scour preloading depth and time.
4.1 This practice provides criteria for the verification of the
5.3.3 Observe/document influent sediment feed samples,
silica sediment removal efficiency of hydrodynamic separators.
initial and post run feed hopper sediment weights, and back-
4.2 Verification can be used to support certification of the
ground sample collection and timing.
technology within different AHJs provided that:
5.3.4 Record/verify times for sediment calibration samples,
4.2.1 HDS units are sized using the resulting performance
sediment feed start, feed stop and flow start/stop.
data to treat the prescribed water quality flow rate or annual
5.3.5 Observe and document the recovery and measurement
mass load requirement at the level of performance desired by
of the mass of sediment captured in the sump and inlet pipe.
the certifying entity.
5.3.6 Document/observe hydraulic testing (flow path, water
4.2.2 Scaling of results to different MTD model sizes is in
elevations, bypass, and head loss).
accordance with this standard.
4.2.3 The technology is designed consistently with the 5.3.7 Check sample labeling, management, and security for
transportation/shipping.
tested unit such that it operates within the specified limits
determined by the verification as well as other restrictions
5.3.8 Ensure calibration of flow meters, scales, etc. per
placed by the certification entity. manufacturer’s requirement.
5.3.9 Review and confirm calculations, and adherence to
5. Performance Evaluation Requirements
protocol as well as the QAPP.
5.3.10 Maintain logbook and documentation of notes,
5.1 Laboratory Qualifications—The testing laboratory shall
measurements, etc.
be capable of conducting all testing in strict accordance with
the applicable laboratory test methods. Testing shall be con-
5.4 Quality Assurance Project Plan—Prior to testing the
ducted at either an independent test facility or at a manufac-
laboratory shall submit a QAPP for approval to the verification
turer’s laboratory under the direct supervision of a qualified
entity. The QAPP format will be designated by the verification
third party observer. There shall be no conflict of interest
entity. Recommended minimum content for QAPP inclusion:
between the independent test facility or third party observer
5.4.1 Applicant information.
and the manufacturer. A conflict of interest is defined as any
5.4.2 Test scope and objectives.
person employed as a third party observer or at an independent
5.4.3 Description of the technology including purpose,
test facility that is directly engaged in the testing or verification
operation, MTD name/model ID being tested, limitations,
process with the potential to undermine the quality of results
methods of bypassing flow, and a standard detail drawing.
for the MTD due to personal, professional, or financial interest.
5.4.4 Description of test setup including flow path
Elements of the supervision shall be outlined in a test QAPP
explanation, sampling/measurement locations, schematic and
and approved by the verification entity prior to commencing
photos, lab MTD unit to be tested, key dimensions disclosed,
with the verification testing.
and equipment to be used.
5.2 Third Party Observer Qualifications—Unless otherwise
5.4.5 Description of testing procedure including sample
specified by the applicable verification entity this section
times/spacing, collection and handling procedures, analysis to
provides guidance on suggested qualifications and professional
be performed, and treatment of data (calculations, statistics,
experience for those serving as a qualified third party observ-
exclusions).
ers.
5.4.6 Lab information including in-house or independent
5.2.1 Minimum Educational Requirements—B.E., B.S., or
test lab, third party observer qualifications and duties, and
B.A. in an engineering-based or science-based curriculum.
analytical laboratory qualifications.
5.2.2 Essential Experience—Experience with hydraulic
testing, water quality monitoring, and analytical measure- 5.5 Laboratory Evaluation of Performance of Hydrody-
ments. Demonstrated knowledge and practice of experimental namic Separators and Settling Devices:
C1893 − 24
5.5.1 A comprehensive laboratory performance evaluation known concentration is allowed. However, an averaging of the
of hydrodynamic separators shall include assessments of sys- results for all spiked samples across all known concentrations
tem hydraulics, sediment removal efficiency, and susceptibility
is not allowed.
to scour, all over a range of flows as defined by the protocol.
5.5.5.4 Results of this proficiency testing must be included
5.5.2 Laboratory performance evaluations shall include at a
in the report submitted for verification.
minimum, testing at seven flow rates ranging from 10 % to
5.5.6 Alternate Unit Configurations—At the discretion of
150 % of the claimed maximum treatment flow rate (MTFR) of
the AHJ, documentation of equivalent performance to the
the device being tested. Unless defined differently by a local
tested unit configuration may be required for alternate unit
jurisdiction, expected MTFR shall be estimated as the flow rate
configurations. To allow for a system configuration that differs
at which the device will achieve >50 % suspended solids
from the tested inlet/outlet piping configuration, a manufac-
removal using the five flow rates from 25 % to 125 % of MTFR
turer may wish to test different inlet/outlet angles to allow for
and the weighting formula provided in Table X1.1 of Appendix
greater flexibility during design and installation. In such
X1. The manufacturer can choose to test at additional operating
instances, at least one alternate inlet/outlet pipe angle must be
rates as desired and should use the resulting performance curve
tested at 25 % and 75 % of the manufacturer’s target MTFR,
to determine the MTFR at which other rates of suspended
and the results must be within 65 % of the original configu-
sediment removal will be achieved.
ration test results. For example, in the original testing configu-
NOTE 2—Regulatory agencies can select weighting factors appropriate
ration the inlet/outlet pipes were set opposite of each other
for their specific local rainfall conditions and desired annualized removal
offset at 180 degrees. In an alternative test, with the inlet pipe
efficiency. The removal efficiency curve can then be used with these
and outlet pipe offset by 90 degrees, two data points are tested
weightings to determine an appropriate MTFR to meet local removal
at 25 % and 75 % of the manufacturer’s target MTFR. If the
efficiency goals. Alternatively, regulatory agencies can select a specific
loading rate from the removal efficiency curve that corresponds to a
initial testing found 62 % and 56 % removal efficiency at 25 %
desired level of removal efficiency.
and 75 % of the target MTFR, the alternate testing must be
5.5.3 All testing shall be conducted on a fullscale, commer- within + or –5 % of those numbers (that is, 57-67 % and
cially available unit. Alternate housing materials such as
51-61 % respectfully). If those targets are met, the piping
aluminum, plastic, fiberglass, or wood may be used to ease the
configuration for the NJCAT verification and NJDEP certifica-
logistics of moving test units within the laboratory. Use of a
tion for the MTD would be extended to include installations
scaled model of the HDS unit for laboratory testing is not
with inlet/outlet pipes offset by up to 90 degrees. Any alternate
permitted.
configuration testing must follow the protocol requirements.
5.5.4 The test sediment shall be characterized in accordance
Additionally, the use of multiple inlets or grate inlets
...

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: C1893 − 23 C1893 − 24
Standard Practice for
Laboratory Performance Verification of Hydrodynamic
Separators for the Treatment of Stormwater Runoff
This standard is issued under the fixed designation C1893; 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 practice covers the criteria for the laboratory verification of Hydrodynamic Separators (HDS) as it relates to the removal
of suspended solids in stormwater runoff.
1.2 HDS manufactured treatment devices are placed as offline or online treatment devices along storm drain pipe lines to remove
suspended solids and associated pollutants from stormwater runoff. These devices may be used to target removal of other pollutants
which are not covered in this standard. The criteria in this standard specifically relate to the removal of silica particles in controlled
laboratory conditions, which is considered an appropriate surrogate for predicting the removal of stormwater solids from actual
stormwater runoff.
1.3 This practice provides guidelines for independent regulatory entities, collectively referred to as Authority Having Jurisdictions
(AHJs), to streamline data requirements for the certification of HDS devices within their jurisdiction. For any given AHJ, additional
criteria may also apply.
1.4 Units—The values stated in inch-pound units are to be regarded as standard, except for methods to establish and report
sediment concentration and particle size. It is convention to exclusively describe sediment concentration in mg/L and particle size
in mm or μm, both of which are SI units. The SI units given in parentheses are mathematical conversions, which are provided for
information purposes only and are not considered standard. Reporting of test results in units other than inch-pound units shall not
be regarded as non-conformance with this test method.
1.5 Acceptance of test results attained according to this specification may be subject to specific requirements set by a Quality
Assurance Project Plan (QAPP), a specific verification protocol, or AHJ. It is advised to review one or all of the above to ensure
compliance.
1.6 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.
NOTE 1—This practice is also intended to ensure that the data resulting from completion of testing in accordance with the ASTM test methods referenced
herein can be utilized to satisfy the requirements of the New Jersey Department of Environmental Protection’s manufactured treatment device (MTD)
certification process.
This practice is under the jurisdiction of ASTM Committee E64 on Stormwater Control Measures and is the direct responsibility of Subcommittee E64.01 on Lab
Evaluation.
Current edition approved April 15, 2023March 1, 2024. Published May 2023March 2024. Originally approved in 2023. Last previous edition approved in 2023 as
C1893 - 23. DOI: 10.1520/C1893-23.10.1520/C1893-24.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1893 − 24
1.7 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:
C1745/C1745M Test Method for Measurement of Hydraulic Characteristics of Hydrodynamic Stormwater Separators and
Underground Settling Devices
C1746/C1746M Test Method for Measurement of Suspended Sediment Removal Efficiency of Hydrodynamic Stormwater
Separators and Underground Settling Devices
D3977 Test Methods for Determining Sediment Concentration in Water Samples
D4959 Test Method for Determination of Water Content of Soil By Direct Heating
D6913/D6913M Test Methods for Particle-Size Distribution (Gradation) of Soils Using Sieve Analysis
D7928 Test Method for Particle-Size Distribution (Gradation) of Fine-Grained Soils Using the Sedimentation (Hydrometer)
Analysis
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
E3317 Specification for Silica-Based Sediments for the Evaluation of Stormwater Treatment Devices
E3318 Terminology for Standards Relating to Stormwater Control Measures
E3373 Test Method for Scour of Hydrodynamic Separators and Settling Devices
2.2 Additional References:
New Jersey Department of Environmental Protection Laboratory Protocol to Assess Total Suspended Solids Removal by a
Hydrodynamic Sedimentation Manufactured Treatment Device” January 1, 2021
NJDEP Laboratory Test Protocols and Verification Procedure: NJCAT Interpretations”, NJDEP, August 4, 2021
3. Terminology
3.1 Definitions:
3.1.1 For definitions of common technical terms used in this standard, refer to Terminology E3318.
4. Significance and Use
4.1 This practice provides criteria for the verification of the silica sediment removal efficiency of hydrodynamic separators.
4.2 Verification can be used to support certification of the technology within different AHJs provided that:
4.2.1 HDS units are sized using the resulting performance data to treat the prescribed water quality flow rate or annual mass load
requirement at the level of performance desired by the certifying entity.
4.2.2 Scaling of results to different MTD model sizes is in accordance with this standard.
4.2.3 The technology is designed consistently with the tested unit such that it operates within the specified limits determined by
the verification as well as other restrictions placed by the certification entity.
5. Performance Evaluation Requirements
5.1 Laboratory Qualifications—The testing laboratory shall be capable of conducting all testing in strict accordance with the
applicable laboratory test methods. Testing shall be conducted at either an independent test facility or at a manufacturer’s
laboratory under the direct supervision of a qualified third party observer. There shall be no conflict of interest between the
independent test facility or third party observer and the manufacturer. A conflict of interest is defined as any person employed as
a third party observer or at an independent test facility that is directly engaged in the testing or verification process with the
potential to undermine the quality of results for the MTD due to personal, professional, or financial interest. Elements of the
supervision shall be outlined in a test QAPP and approved by the verification entity prior to commencing with the verification
testing.
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.
C1893 − 24
5.2 Third Party Observer Qualifications—Unless otherwise specified by the applicable verification entity this section provides
guidance on suggested qualifications and professional experience for those serving as a qualified third party observers.
5.2.1 Minimum Educational Requirements—B.E., B.S., or B.A. in an engineering-based or science-based curriculum.
5.2.2 Essential Experience—Experience with hydraulic testing, water quality monitoring, and analytical measurements. Demon-
strated knowledge and practice of experimental design and setup, sampling methods, handling, sample security (that is, chain of
custody), task documentation, and data management.
5.2.3 Relevant Experiences—Consulting or academic (reporting, general laboratory practices).
5.3 Expectations for Third Party Observer—The third party observer shall witness all active aspects of testing carried out at a
manufacturers facility as described herein as well as any supplemental test runs, measurements, sampling and analysis:
5.3.1 Observe and document the preparation and collection of test sediment samples for PSD analysis, background suspended
sediment concentration (SSC) samples, and effluent SSC scour test sediment samples.
5.3.2 Document test setup, including key dimensions, such as, pipe sizes including diameter, slopes, and condition, hopper
location and height, false floor elevation, location of sediment injection point, and sediment scour preloading depth and time.
5.3.3 Observe/document influent sediment feed samples, initial and post run feed hopper sediment weights, and background
sample collection and timing.
5.3.4 Record/verify times for sediment calibration samples, sediment feed start, feed stop and flow start/stop.
5.3.5 Observe and document the recovery and measurement of the mass of sediment captured in the sump and inlet pipe.
5.3.6 Document/observe hydraulic testing (flow path, water elevations, bypass, and head loss).
5.3.7 Check sample labeling, management, and security for transportation/shipping.
5.3.8 Ensure calibration of flow meters, scales, etc. per manufacturer’s requirement.
5.3.9 Review and confirm calculations, and adherence to protocol as well as the QAPP.
5.3.10 Maintain logbook and documentation of notes, measurements, etc.
5.4 Quality Assurance Project Plan—Prior to testing the laboratory shall submit a QAPP for approval to the verification entity.
The QAPP format will be designated by the verification entity. Recommended minimum content for QAPP inclusion:
5.4.1 Applicant information.
5.4.2 Test scope and objectives.
5.4.3 Description of the technology including purpose, operation, MTD name/model ID being tested, limitations, methods of
bypassing flow, and a standard detail drawing.
5.4.4 Description of test setup including flow path explanation, sampling/measurement locations, schematic and photos, lab MTD
unit to be tested, key dimensions disclosed, and equipment to be used.
5.4.5 Description of testing procedure including sample times/spacing, collection and handling procedures, analysis to be
performed, and treatment of data (calculations, statistics, exclusions).
5.4.6 Lab information including in-house or independent test lab, third party observer qualifications and duties, and analytical
laboratory qualifications.
C1893 − 24
5.5 Laboratory Evaluation of Performance of Hydrodynamic Separators and Settling Devices:
5.5.1 A comprehensive laboratory performance evaluation of hydrodynamic separators shall include assessments of system
hydraulics, sediment removal efficiency, and susceptibility to scour, all over a range of flows as defined by the protocol.
5.5.2 Laboratory performance evaluations shall include at a minimum, testing at seven flow rates ranging from 10 % to 150 % of
the claimed maximum treatment flow rate (MTFR) of the device being tested. Unless defined differently by a local jurisdiction,
expected MTFR shall be estimated as the flow rate at which the device will achieve >50 % suspended solids removal using the
five flow rates from 25 % to 125 % of MTFR and the weighting formula provided in Table X1.1 of Appendix X1. The manufacturer
can choose to test at additional operating rates as desired and should use the resulting performance curve to determine the MTFR
at which other rates of suspended sediment removal will be achieved.
NOTE 2—Regulatory agencies can select weighting factors appropriate for their specific local rainfall conditions and desired annualized removal efficiency.
The removal efficiency curve can then be used with these weightings to determine an appropriate MTFR to meet local removal efficiency goals.
Alternatively, regulatory agencies can select a specific loading rate from the removal efficiency curve that corresponds to a desired level of removal
efficiency.
5.5.3 All testing shall be conducted on a fullscale, commercially available unit. Alternate housing materials such as aluminum,
plastic, fiberglass, or wood may be used to ease the logistics of moving test units within the laboratory. Use of a scaled model of
the HDS unit for laboratory testing is not permitted.
5.5.4 The test sediment shall be characterized in accordance with Specification E3317. The sediment particle size distributions for
performance and scour testing shall be in accordance with Specification E3317, Table 1, Sediment A and Sediment C respectively.
5.5.5 All analytical methods used for TSS (measured as suspended sediment concentration, or SSC) samples collection and
analyses required by the protocol (that is, Test Methods D4959, D3977, D6913/D6913M, D7928, and USGS I3765-85) must be
conducted by a laboratory certified by a NELAP or ISO recognized accreditation body to conduct the specific test method. If a
laboratory is not specifically certified for Test Methods D3977, they must demonstrate proficiency as described in 5.5.5.1. All
analytical analysis must be performed by an independent accredited laboratory.
5.5.5.1 Prior to the start of testing, an analytical laboratory shall demonstrate proficiency in executing Test Methods D3977 as
follows:
5.5.5.2 In order to ensure analytical laboratories, not certified for Test Methods D3977, are proficient in analyzing samples in
accordance with Test Methods D3977, two spiked samples shall be prepared by the vendor and analyzed by the laboratory prior
to the start of testing.
5.5.5.2 Spiked SSC samples shall be prepared using the same test sediment prepared for SSC testing. Spiked SSC samples shall
be prepared at concentrations between 20 mg/Ltwo known concentrations of 20.0 6 5.0 mg ⁄L and 50 mg/L. These spiked samples
should be separated by at least 15 mg/L in concentration.50.0 6 5.0 mg/L. A minimum of three duplicate spiked samples shall be
prepared and submitted for analysis at each of those two known concentrations.
5.5.5.3 SSC Spiked SSC samples shall be prepared using the same test sediment prepared for SSC testing. SSC recovery results
for spiked samples shall be 615 %within 615 % of the two known concentrationconcentrations to b
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