ASTM D8151-19e1

Standard Practice for Obtaining Rainfall Runoff from Unvegetated Rolled and Hydraulic Erosion Control Products (RECPs and HECPs) for Acute Ecotoxicity Testing

SIGNIFICANCE AND USE
5.1 A large number of erosion control product manufacturers produce a variety of RECPs and HECPs that are designed to be applied to any land surface to stabilize soils and prevent erosion. Many of these products are engineered to absorb moisture and remain in place even under extreme rainfall events and are composed of substances that could go into solution with runoff. Based on the characteristics of these products and their intended and actual use in the environment, the most likely scenario through which aquatic organisms would be exposed to these products or their soluble components is through storm water runoff. Further, because such runoff events typically last for minutes to hours rather than days, use of acute (48 h) toxicity testing methodology is appropriate to model expected environment exposures.
Note 1: The quality of the result produced by this standard is dependent on the competence of the personnel performing it, and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with Practice D3740 does not in itself assure reliable results. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some of those factors.
SCOPE
1.1 This practice establishes the guidelines, requirements, and procedures for obtaining rainfall runoff of unvegetated rolled and hydraulic erosion control products (RECPs and HECPs) during bench-scale conditions from simulated rainfall to be sent out for acute ecotoxicity testing.  
1.2 This practice obtains unvegetated erosion control product (ECP) runoff from rainsplash-induced erosion under bench-scale conditions using bench-scale collection procedures.  
1.3 Units—The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard.  
1.4 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026, unless superseded by this test method.  
1.4.1 The procedures used to specify how data are collected/recorded and calculated in the standard are regarded as the industry standard. In addition, they are representative of the significant digits that generally should be retained. The procedures used do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user’s objectives; and it is common practice to increase or reduce significant digits of reported data to be commensurate with these considerations. It is beyond the scope of these test methods to consider significant digits used in analysis methods for engineering data.  
1.5 This practice offers a set of instructions for performing one or more specific operations. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this practice may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without consideration of a project’s many unique aspects. The word “Standard” in the title of this document means only that the document has been approved through the ASTM consensus process.  
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.  
1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Dev...

General Information

• Status: Published
• Publication Date: 14-Jun-2019
• ICS: 13.080.99 - Other standards related to soil quality
• Technical Committee: D18 - Soil and Rock
• Drafting Committee: D18.25 - Erosion and Sediment Control Technology

Relations

• Replaces: ASTM D8151-19 - Standard Practice for Obtaining Rainfall Runoff from Unvegetated Rolled and Hydraulic Erosion Control Products (RECPs and HECPs) for Acute Ecotoxicity Testing
• Effective Date: 15-Jun-2019
• Refers: ASTM D4753-24 - Standard Guide for Evaluating, Selecting, and Specifying Balances and Standard Masses for Use in Soil, Rock, and Construction Materials Testing
• Effective Date: 01-Feb-2024
• Refers: ASTM D3740-23 - Standard Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• Effective Date: 01-Nov-2023
• Refers: ASTM D3740-19 - Standard Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• Effective Date: 01-Oct-2019
• Refers: ASTM D4972-19 - Standard Test Methods for pH of Soils
• Effective Date: 01-May-2019
• Refers: ASTM D4972-18 - Standard Test Methods for pH of Soils
• Effective Date: 01-Jul-2018
• Refers: ASTM D4318-17 - Standard Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of Soils
• Effective Date: 01-Jun-2017
• Refers: ASTM D4318-17e1 - Standard Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of Soils
• Effective Date: 01-Jun-2017
• Refers: ASTM D6475-17 - Standard Test Method for Measuring Mass per Unit Area of Erosion Control Blankets
• Effective Date: 15-Feb-2017
• Refers: ASTM D6566-17 - Standard Test Method for Measuring Mass per Unit Area of Turf Reinforcement Mats
• Effective Date: 01-Jan-2017
• Refers: ASTM D4753-15 - Standard Guide for Evaluating, Selecting, and Specifying Balances and Standard Masses for Use in Soil, Rock, and Construction Materials Testing
• Effective Date: 01-May-2015
• Refers: ASTM D653-14 - Standard Terminology Relating to Soil, Rock, and Contained Fluids
• Effective Date: 01-Aug-2014
• Refers: ASTM D6566-14 - Standard Test Method for Measuring Mass per Unit Area of Turf Reinforcement Mats
• Effective Date: 01-May-2014
• Refers: ASTM D4972-13 - Standard Test Method for pH of Soils
• Effective Date: 01-Nov-2013
• Refers: ASTM D7101-13 - Standard Index Test Method for Determination of Unvegetated Rolled Erosion Control Product (RECP) Ability to Protect Soil from Rain Splash and Associated Runoff Under Bench-Scale Conditions
• Effective Date: 15-Jun-2013

Overview

ASTM D8151-19e1: Standard Practice for Obtaining Rainfall Runoff from Unvegetated Rolled and Hydraulic Erosion Control Products (RECPs and HECPs) for Acute Ecotoxicity Testing is an internationally recognized ASTM standard. It specifies procedures for collecting rainfall runoff from unvegetated rolled and hydraulic erosion control products under controlled, bench-scale laboratory conditions. The collected runoff is intended for use in acute ecotoxicity testing, simulating how aquatic organisms may be exposed to products or their soluble components during stormwater runoff events.

Erosion control products (ECPs), including RECPs and HECPs, are widely deployed to stabilize soil and prevent erosion on bare land surfaces. Many of these products are exposed to intense rainfall, potentially leaching substances into runoff, which may impact downstream aquatic environments. ASTM D8151-19e1 offers a consistent approach to acquiring representative runoff samples for regulatory testing and research.

Key Topics

• Purpose and Scope
  • Provides guidelines for generating and collecting rainfall runoff from unvegetated RECPs and HECPs using simulated rainfall under laboratory (bench-scale) conditions.
  • Runoff collected is suitable for acute (48-hour) ecotoxicity testing.
• Importance in Environmental Protection
  • Supports risk assessment of materials used in soil stabilization by evaluating potential impacts on aquatic ecosystems.
  • Focuses on likely exposure scenarios - short, intense stormwater events.
• Test Procedures
  • Uses standardized equipment, such as calibrated rainfall simulators and inclined test beds, to ensure reliable and reproducible conditions.
  • Specifies types of materials, sample preparation, and collection/filtration methods.
  • Emphasizes use of SI units and significant digits per industry best practices.
• Quality and Reliability
  • Stresses the importance of competent personnel and suitable laboratory infrastructure.
  • Points to additional ASTM and EPA practices for laboratory competence and data consistency.

Applications

ASTM D8151-19e1 is important across several sectors:

• Product Testing and Certification
  • Manufacturers of erosion control products use the standard to demonstrate environmental compliance and product safety.
  • Regulatory agencies may require testing according to this method for project approvals and permitting.
• Environmental Impact Assessment
  • Consultants and environmental engineers apply this practice in site evaluations to assess the risk of pollutant transport via runoff.
• Research and Development
  • Laboratories and academic researchers use the methodology to compare the relative environmental safety of ECPs and improve formulations.
• Stormwater Management
  • Helps inform best practices for land disturbance, construction site management, and restoration projects, ensuring that installed ECPs do not adversely impact nearby waterways.

Related Standards

For a comprehensive approach to runoff sampling and ecotoxicity studies involving erosion control products, the following standards and guidelines are relevant:

• ASTM D3740 - Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock
• ASTM D653 - Terminology Relating to Soil, Rock, and Contained Fluids
• ASTM D698 - Test Methods for Laboratory Compaction Characteristics of Soil
• ASTM D4318 - Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of Soils
• ASTM D6026 - Practice for Using Significant Digits in Geotechnical Data
• ASTM D6475 and D6566 - Test Methods for Measuring Mass per Unit Area of Erosion Control Blankets and Turf Reinforcement Mats
• ASTM D6913 - Test Methods for Particle-Size Distribution of Soils
• ASTM D7101 - Methods for Determination of RECP Ability to Protect Soil from Rain Splash and Runoff
• EPA Method 2002 - Measuring Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms

By adhering to ASTM D8151-19e1 and related standards, organizations enhance the reliability of environmental testing and contribute to informed decision-making in soil erosion management and water protection.

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.
´1
Designation: D8151 − 19
Standard Practice for
Obtaining Rainfall Runoff from Unvegetated Rolled and
Hydraulic Erosion Control Products (RECPs and HECPs) for
Acute Ecotoxicity Testing
This standard is issued under the fixed designation D8151; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—Eq 4 was editorially corrected in March 2020.
1. Scope the adequacy of a given professional service must be judged,
nor should this document be applied without consideration of
1.1 This practice establishes the guidelines, requirements,
a project’s many unique aspects. The word “Standard” in the
and procedures for obtaining rainfall runoff of unvegetated
title of this document means only that the document has been
rolled and hydraulic erosion control products (RECPs and
approved through the ASTM consensus process.
HECPs) during bench-scale conditions from simulated rainfall
1.6 This standard does not purport to address all of the
to be sent out for acute ecotoxicity testing.
safety concerns, if any, associated with its use. It is the
1.2 This practice obtains unvegetated erosion control prod-
responsibility of the user of this standard to establish appro-
uct(ECP)runofffromrainsplash-inducederosionunderbench-
priate safety, health, and environmental practices and deter-
scale conditions using bench-scale collection procedures.
mine the applicability of regulatory limitations prior to use.
1.3 Units—The values stated in SI units are to be regarded
1.7 This international standard was developed in accor-
as the standard. No other units of measurement are included in
dance with internationally recognized principles on standard-
this standard.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
1.4 All observed and calculated values shall conform to the
mendations issued by the World Trade Organization Technical
guidelines for significant digits and rounding established in
Barriers to Trade (TBT) Committee.
Practice D6026, unless superseded by this test method.
1.4.1 Theproceduresusedtospecifyhowdataarecollected/
2. Referenced Documents
recorded and calculated in the standard are regarded as the
2.1 ASTM Standards:
industry standard. In addition, they are representative of the
D653Terminology Relating to Soil, Rock, and Contained
significant digits that generally should be retained. The proce-
Fluids
dures used do not consider material variation, purpose for
D698Test Methods for Laboratory Compaction Character-
obtaining the data, special purpose studies, or any consider-
istics of Soil Using Standard Effort (12,400 ft-lbf/ft (600
ations for the user’s objectives; and it is common practice to
kN-m/m ))
increase or reduce significant digits of reported data to be
D3740Practice for Minimum Requirements for Agencies
commensuratewiththeseconsiderations.Itisbeyondthescope
Engaged in Testing and/or Inspection of Soil and Rock as
of these test methods to consider significant digits used in
Used in Engineering Design and Construction
analysis methods for engineering data.
D4318Test Methods for Liquid Limit, Plastic Limit, and
1.5 This practice offers a set of instructions for performing
Plasticity Index of Soils
one or more specific operations. This document cannot replace
D4753Guide for Evaluating, Selecting, and Specifying Bal-
education or experience and should be used in conjunction
ances and Standard Masses for Use in Soil, Rock, and
with professional judgment. Not all aspects of this practice may
Construction Materials Testing
be applicable in all circumstances. This ASTM standard is not
D4972Test Methods for pH of Soils
intended to represent or replace the standard of care by which
D6026Practice for Using Significant Digits in Geotechnical
Data
ThistestmethodisunderthejurisdictionofASTMCommitteeD18onSoiland
Rock and is the direct responsibility of Subcommittee D18.25 on Erosion and For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Sediment Control Technology. contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Current edition approved June 15, 2019. Published July 2019. DOI: 10.1520/ Standards volume information, refer to the standard’s Document Summary page on
D8151-19E01 the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
D8151 − 19
D6475Test Method for Measuring Mass per Unit Area of moisture and remain in place even under extreme rainfall
Erosion Control Blankets events and are composed of substances that could go into
D6566Test Method for Measuring Mass Per Unit Area of solution with runoff. Based on the characteristics of these
Turf Reinforcement Mats products and their intended and actual use in the environment,
D6913Test Methods for Particle-Size Distribution (Grada- the most likely scenario through which aquatic organisms
tion) of Soils Using Sieve Analysis would be exposed to these products or their soluble compo-
D7101IndexTestMethodforDeterminationofUnvegetated nents is through storm water runoff. Further, because such
RolledErosionControlProduct(RECP)AbilitytoProtect runoff events typically last for minutes to hours rather than
Soil from Rain Splash and Associated Runoff Under days, use of acute (48 h) toxicity testing methodology is
Bench-Scale Conditions appropriate to model expected environment exposures.
2.2 EPA Standards:
NOTE 1—The quality of the result produced by this standard is
Method 2002Methods for Measuring the Acute Toxicity of
dependent on the competence of the personnel performing it, and the
Effluents and Receiving Waters to Freshwater and Marine
suitability of the equipment and facilities used. Agencies that meet the
criteria of Practice D3740 are generally considered capable of competent
Organisms
and objective testing/sampling/inspection/etc. Users of this standard are
Method 2002.0CERIODAPHNIA DUBIA Acute Toxicity
cautioned that compliance with Practice D3740 does not in itself assure
Tests with Effluents and Receiving Waters
reliable results. Reliable results depend on many factors; Practice D3740
Method2021.0DAPHNIAPULEXANDD.MAGNAAcute
provides a means of evaluating some of those factors.
Toxicity Tests with Effluents and Receiving Waters
6. Apparatus
3. Terminology
6.1 Rainfall Simulator—A laboratory device capable of
3.1 Definitions:
simulatingrainfallusingsprinklers,nozzlesordropemittersto
3.1.1 Fordefinitionsofcommontechnicaltermsusedinthis
create uniform drops with a diameter, D ,of3.0 6 0.25 mm
standard, refer to Terminology D653.
from a drop height of 2000 6 20 mm above the lowest point
of the incline structure. It shall also be capable of producing a
4. Summary of Practice
rainfall intensity of 100 6 5 mm/h and must be centered over
4.1 This practice is used to obtain the rainfall runoff needed
the incline structure to provide uniform rain application.
to determine the acute toxicity of rolled and hydraulic erosion
6.2 Incline Structure—A device comprised of 3 adjacent
control products (RECPs/HECPs) for a slope of 3:1 (H:V) and
“runoff ramps” each having an opening at its lower end to
a rainfall intensity of 100 6 5 mm/h.
accommodate a recessed soil container. The ramps shall be
4.2 Beforetesting,therainfallsimulatorsystemiscalibrated
made of metal and 1000 6 100 mm in length, 250 6 25 mm
for the rainfall intensity and slope intended for use. The sand
wide, and have metal or plastic raised dividers of at least 25.0
used in the soil containers is also tested prior to use.
mm tall between the ramps to prevent cross-ramp soil splash
and run-on/runoff. The structure shall have and maintain a
4.3 The sand is compacted into six soil containers.Three of
the soil containers are then protected with the unvegetated slope gradient of 3:1 (H:V). It is permissible for the structure
to be adjustable providing it is able to achieve and maintain a
RECPorHECP;theotherthreeremainunprotected.The3bare
soil/unprotected containers are placed in the runoff ramps, gradient of 3:1 for use in this standard. Test Method D7101
provides a general figure of the incline structure.
covered, and the rainfall simulator is turned on and allowed to
come to equilibrium.After equilibrium is reached, the cover is
6.3 Runoff Collection Containers—Any type of bucket hav-
removed,thecollectioncontainersaremovedintopositionand
ing sufficient diameter and capacity to collect and hold all the
thetestcommencesatarainfallintensityrateof100 65mm/h
runoff from each of the ramps.
for30min.Attheendofthetest,therunoffcollectedfromeach
6.4 Soil Containers—Watertight, plastic pipe section cylin-
ramp is filtered, measured, and poured into a container. The
ders that are nominally 200 6 10 mm inside diameter with a
water from the 3 runoff ramps is combined into a single
height of 100 6 10 mm.
container. The single water sample is allowed to settle, then
6.5 Filter Paper—Grade 3 filter paper having the following
decanted to obtain the control sample to be shipped overnight
for acute toxicity testing. This process is then repeated for the characteristics: typical particle retention in liquid of 6 µm,
nominal thickness of 390 µm, typical water flow rate of 28
three soil containers that are unvegetated RECP or HECP
protected. mL/min,nominalashcontentof0.06%,andmadeofcellulose.
6.6 Measuring Device—A surveyor’s rod, tape measure, or
5. Significance and Use
similar with a minimum length of 2 m and divisions of 1 mm.
5.1 A large number of erosion control product manufactur-
6.7 Timing Device—A clock, stopwatch, digital timer, or
ers produce a variety of RECPs and HECPs that are designed
comparable device readable to 1 second or better.
to be applied to any land surface to stabilize soils and prevent
6.8 Rain Gauges—Any type of container is allowed pro-
erosion. Many of these products are engineered to absorb
vided they meet the following specifications: Each container
must have identical dimensions (same diameters and depths).
AvailablefromUnitedStatesEnvironmentalProtectionAgency(EPA),William
Each container must be calibrated such that the marked
Jefferson Clinton Bldg., 1200 Pennsylvania Ave., NW, Washington, DC 20460,
http://www.epa.gov. graduation lines accurately measure the amount of rainfall
´1
D8151 − 19
within 61 mm. Lines shall be marked every 1 mm. Clear passing the 2.00 mm (No. 10) sieve, 65% passing the 0.850
plastic or glass containers are recommended. mm (No. 20) sieve, 33% passing the 0.300 mm (No. 50) sieve
and 18% passing the 0.106 mm (No. 140) sieve. See Test
6.9 Graduated Cylinders—The capacity of the graduated
Method D7101 for an example graph.
cylinders must be large enough to measure the volume of
7.1.2 Plasticity Index as determined by Test Methods
runoff water collected in the rain gauges during calibration of
D4318.
the rainfall simulator and the volume of water obtained in the
7.1.3 Optimumwatercontentandmaximumdryunitweight
collection buckets during testing. Typically, a 250 mL gradu-
as determined by Test Methods D698. Determine and record
ated cylinder has enough capacity. The graduated cylinders
the value corresponding to 90 % of the maximum dry unit
must be readable to the nearest 1 mL.
weight.
6.10 Oven—Vented, thermostatically controlled oven ca-
7.1.4 pH as determined by Test Method D4972.
pable of maintaining a uniform temperature of 43 6 5°C
7.2 RECP/HECP—The representative sample shall be ob-
throughout the drying chamber. Typically, a forced-draft oven
tained from a package, roll or both. The package or roll must
satisfies these requirements.
be checked for visible damage, such as tears, rips, and holes,
6.11 Balance—Balances shall conform to the requirements
prior to use. If the packaging is damaged, do not use it for
of Guide D4753. The balance shall have a readability without
testing. All RECPs/HECPs shall be free of extraneous foreign
estimation of 0.0001 g. The capacity of this balance will need
materials, such as, metals or non-standard plastics that could
to exceed the mass of the container plus flour pellets.
interferewithproductionapplication.TheRECPorHECPshall
6.12 Sieves—A 0.212 mm (No. 70) sieve, lid and pan, as
be applied to the soil surface in accordance with the manufac-
well as the following sieves are needed: 6.3 mm ( ⁄4 in.), 4.75
turer’s recommended application methods.
mm (No. 4), 4.0 mm (No. 5), 3.35 mm (No. 6), 2.8 mm (No.
7.2.1 Determine and record the mass per unit area in
7), 2.36 mm (No. 8), 2.00 mm (No. 10), 1.7 mm (No. 12), 1.4
accordance with Test Methods D6475 and D6566 for the
mm (No. 14), 1.0 mm (No.18), 0.500 mm (No. 35), and 0.250
RECP/HECP being evaluated in this standard.
mm (No. 60). 2
7.2.2 Obtain a representative sample of 1 m when evalu-
6.13 Miscellaneous—The following items are also needed:
ating RECPs and 500 g when evaluating HECPs. Select 3 test
waterproof barrier (plastic sheeting, lids, canopy), 230 mm specimens from the representative sample for use in testing.
wide by 25.4 mm deep cake pans, flour sifter, Pillsbury Best
Make the test specimens large enough to cover the entire soil
all-purpose flour (Note 2), ruler, evaporating dishes, desiccator container surfaces and in accordance with the manufacturer’s
(optional), sieve shaker (optional), high-density polyethylene installation instructions.
(HDPE) containers, bucket/container large enough to hold the
filtered water from all three runoff ramps, coolers, and ice.
8. Calibration of Rainfall Simulator
NOTE 2—The subcommittee is committed to identifying alternate flour 8.1 Calibration of the rainfall simulator is performed by
as soon as the test described in this standard is performed outside the
measuring and determining the drop height, the rainfall inten-
United States.
sityanduniformdistribution,andraindropsizewiththeincline
structure at the specified slope.At a minimum, this calibration
7. Materials and Sampling
shall be done before initial use, after equipment repair/
7.1 Soil Type—The soil type to be used during testing is
maintenance, and annually thereafter.
sandconformingtothepropertieslistedinTable1.Performthe
8.2 Drop Height—Positiontheinclinestructuresuchthatthe
following testing on the bulk sand according to the listed
slopeis3:1(H:V).Determineandrecordthedropheightofthe
methods. Record the results of the testing in accordance with
raindrops to the lowest point of the incline structure to the
the requirements of each individual standard. These tests must
nearest 1 mm using a measuring device. Make adjustments as
be done before initial use of the bulk sand sample and anytime
needed.
thereafter when the bulk sand sample has been replenished
with new sand. Make sure the bulk sand sample has been
8.3 Rainfall Intensity and Distribution:
blended well to provide a representative specimen for initial
8.3.1 Maintain the 3:1 (H:V) slope of the incline structure.
testing.
Place a rain gauge in the middle of each ramp. Cover the rain
7.1.1 Particle-size distribution as determined by Test Meth-
gauges with a waterproof barrier, such as plastic sheeting, lids
ods D6913. The target gradation curve that should provide a
or canopy. Turn on the rainfall simulator and allow it to come
material with grain size properties meeting Table 1 is 100%
toequilibrium,thenquicklyremovethewaterproofbarrierand
start the timing device. Allow the simulator to run for a
minimum of 15 mins (Note 3). After 15 min, turn off the
TABLE 1 Typical Soil Properties
rainfall simulator and stop the timing device. Record the
Property Sand Sieve Size(s)
duration of the rainfall to the nearest 1 second.
D (mm) D < 4.75 No. 4
100 100
D (mm) 4.75 > D > 0.850 No. 4 and No. 20
85 85
NOTE 3—If desired, the time interval for conducting the calibration can
D (mm) 0.850 > D > 0.300 No. 20 and No. 50
50 50
be longer than 15 minutes.
D (mm) 0.300 > D >0.075 No. 50 and No. 200
15 15
Plasticity Index Nonplastic
8.3.2 Determineandrecordtheamountofwatercollectedin
pH 6.0-8.0
each rain gauge to the nearest 1 mm. The rainfall intensity is
...