Geotechnical investigation and testing - Geohydraulic testing - Part 4: Pumping tests (ISO/DIS 22282-4:2020)

Geotechnische Erkundung und Untersuchung - Geohydraulische Versuche - Teil 4: Pumpversuche (ISO/DIS 22282-4:2020)

Dieser Teil von ISO 22282 behandelt Anforderungen an Pumpversuche als Teil der geotechnischen Erkundung nach EN 1997-1 und EN 1997-2.
Allgemeine Regeln für die Planung und Ausführung von geohydraulischen Feldversuchen werden in ISO 22282-1 behandelt.
Grundsätzlich besteht ein Pumpversuch aus Folgendem:
- Druckabsenkung durch Abpumpen von Wasser aus einem Brunnen (dem Versuchsbrunnen);
- Messen des abgepumpten Volumens und des Wasserspiegels im Versuchsbrunnen und in den Grundwassermessstellen vor, während und nach dem Pumpen als Funktion der Zeit.
Dieser Teil von ISO 22282 gilt für Pumpversuche in Grundwasserleitern, deren Durchlässigkeit so ist, dass das Abpumpen aus einem Brunnen - in Abhängigkeit von den Bedingungen des Baugrunds und dem Zweck - zu einer Absenkung der piezometrischen Höhe innerhalb von Stunden oder Tagen führen kann. Das Dokument behandelt Pumpversuche in Locker- und Felsgestein.
Bei den durch diesen Teil von ISO 22282 abgedeckten Versuchen handelt es sich um diejenigen, die zur Auswertung der hydrodynamischen Parameter eines Grundwasserleiters und von Brunnenparametern vorgesehen sind, z. B.:
- allgemeiner Durchlässigkeitsbeiwert des Grundwasserleiters;
- Einflussradius des Pumpens;
- Förderrate für einen Brunnen;
- Auswirkung in Bezug auf die Absenkung in einem Grundwasserleiter während des Pumpens;
- Skin-Faktor;
- Brunnenspeicherkoeffizient;
- Auswirkung in Bezug auf die Wiederherstellung in einem Grundwasserleiter nach dem Pumpen.

Reconnaissance et essais géotechniques - Essais géohydrauliques - Partie 4: Essais de pompage (ISO/DIS 22282-4:2020)

Geotehnično preiskovanje in preskušanje - Hidrogeološke preiskave - 4. del: Črpalni preskus (ISO/DIS 22282-4:2020)

General Information

Status
Not Published
Public Enquiry End Date
09-Jul-2020
Technical Committee
Current Stage
4020 - Public enquire (PE) (Adopted Project)
Start Date
18-May-2020
Due Date
05-Oct-2020
Completion Date
10-Aug-2020

RELATIONS

Buy Standard

Draft
oSIST prEN ISO 22282-4:2020
English language
30 pages
sale 10% off
Preview
sale 10% off
Preview

e-Library read for
1 day

Standards Content (sample)

SLOVENSKI STANDARD
oSIST prEN ISO 22282-4:2020
01-julij-2020
Geotehnično preiskovanje in preskušanje - Hidrogeološke preiskave - 4. del:
Črpalni preskus (ISO/DIS 22282-4:2020)

Geotechnical investigation and testing - Geohydraulic testing - Part 4: Pumping tests

(ISO/DIS 22282-4:2020)
Geotechnische Erkundung und Untersuchung - Geohydraulische Versuche - Teil 4:
Pumpversuche (ISO/DIS 22282-4:2020)

Reconnaissance et essais géotechniques - Essais géohydrauliques - Partie 4: Essais de

pompage (ISO/DIS 22282-4:2020)
Ta slovenski standard je istoveten z: prEN ISO 22282-4
ICS:
93.020 Zemeljska dela. Izkopavanja. Earthworks. Excavations.
Gradnja temeljev. Dela pod Foundation construction.
zemljo Underground works
oSIST prEN ISO 22282-4:2020 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN ISO 22282-4:2020
---------------------- Page: 2 ----------------------
oSIST prEN ISO 22282-4:2020
DRAFT INTERNATIONAL STANDARD
ISO/DIS 22282-4
ISO/TC 182 Secretariat: BSI
Voting begins on: Voting terminates on:
2020-04-21 2020-07-14
Geotechnical investigation and testing — Geohydraulic
testing —
Part 4:
Pumping tests
Reconnaissance et essais géotechniques — Essais géohydrauliques —
Partie 4: Essais de pompage
ICS: 93.020
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 22282-4:2020(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. ISO 2020
---------------------- Page: 3 ----------------------
oSIST prEN ISO 22282-4:2020
ISO/DIS 22282-4:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
---------------------- Page: 4 ----------------------
oSIST prEN ISO 22282-4:2020
ISO/DIS 22282-4:2020(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms, definitions and symbols ............................................................................................................................................................ 2

3.1 Terms and definitions ....................................................................................................................................................................... 2

3.2 Symbols ......................................................................................................................................................................................................... 2

4 Equipment ................................................................................................................................................................................................................... 2

5 Test procedure ........................................................................................................................................................................................................ 3

5.1 Test preparation ..................................................................................................................................................................................... 3

5.1.1 General...................................................................................................................................................................................... 3

5.1.2 Determining the discharge rate for the pumping test ..................................................................... 3

5.2 Arranging the disposal of discharge water ..................................................................................................................... 3

5.3 Executing and equipping the well .......................................................................................................................................... 4

5.3.1 Design of the test well ................................................................................................................................................. 4

5.3.2 Installation procedure .................. ......................................................................................................................... ...... 6

5.3.3 Preparation of the well ............................................................................................................................................... 6

5.4 Executing and equipping the piezometers ......... ............................................................................................................. 6

5.4.1 Installation procedure .................. ......................................................................................................................... ...... 6

5.4.2 Preparation of piezometers .................................................................................................................................... 6

5.5 Execution of the test ........................................................................................................................................................................... 7

5.5.1 General...................................................................................................................................................................................... 7

5.5.2 Pre-pumping monitoring .......................................................................................................................................... 7

5.5.3 Preliminary pumping phase................................................................................................................................... 7

5.5.4 Pumping test .................. .................................................... .................................................................................................. 7

5.5.5 Post-pumping monitoring ....................................................................................................................................... 8

5.6 Uncertainty of measurement ...................................................................................................................................................... 9

5.7 Interruptions in pumping .............................................................................................................................................................. 9

5.8 Decommissioning ................................................................................................................................................................................. 9

6 Test results .................................................................................................................................................................................................................. 9

7 Reports.........................................................................................................................................................................................................................10

7.1 Field report .............................................................................................................................................................................................10

7.1.1 General...................................................................................................................................................................................10

7.1.2 Installation record .......................................................................................................................................................10

7.1.3 Record of measured values and test results ..........................................................................................10

7.2 Test report ................................................................................................................................................................................................11

Annex A (informative) Record of measured values and test results of the pumping test —

Example .......................................................................................................................................................................................................................12

Annex B (informative) Determining the pumping test discharge .......................................................................................14

Annex C (informative) Interpretation of the pumping test results ....................................................................................18

Bibliography .............................................................................................................................................................................................................................26

© ISO 2020 – All rights reserved iii
---------------------- Page: 5 ----------------------
oSIST prEN ISO 22282-4:2020
ISO/DIS 22282-4:2020(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International

Standards adopted by the technical committees are circulated to the member bodies for voting.

Publication as an International Standard requires approval by at least 75 % of the member bodies

casting a vote.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights.

ISO 22282-4 was prepared by the European Committee for Standardization (CEN) Technical Committee

CEN/TC 341, Geotechnical investigation and testing, in collaboration with Technical Committee

ISO/TC 182, Geotechnics, Subcommittee SC 1, Geotechnical investigation and testing, in accordance with

the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).

ISO 22282 consists of the following parts, under the general title Geotechnical investigation and

testing — Geohydraulic testing:
— Part 1: General rules
— Part 2: Water permeability tests in a borehole using open systems
— Part 3: Water pressure tests in rock
— Part 4: Pumping tests
— Part 5: Infiltrometer tests
— Part 6: Water permeability tests in a borehole using closed systems
iv © ISO 2020 – All rights reserved
---------------------- Page: 6 ----------------------
oSIST prEN ISO 22282-4:2020
DRAFT INTERNATIONAL STANDARD ISO/DIS 22282-4:2020(E)
Geotechnical investigation and testing — Geohydraulic
testing —
Part 4:
Pumping tests
1 Scope

This part of ISO 22282 establishes requirements for pumping tests as part of geotechnical investigation

service in accordance with EN 1997-1 and EN 1997-2.

General rules on the planning and execution of geohydraulic field tests are covered by ISO 22282-1.

A pumping test consists in principle of:

— drawing down the piezometric surface of the groundwater by pumping from a well (the test well);

— measuring the pumped discharge and the water level in the test well and piezometers, before, during

and after pumping, as a function of time.

This part of ISO 22282 applies to pumping tests performed on aquifers whose permeability is such that

pumping from a well can create a lowering of the piezometric head within hours or days depending on

the ground conditions and the purpose. It covers pumping tests carried out in soils and rock.

The tests concerned by this part of ISO 22282 are those intended for evaluating the hydrodynamic

parameters of an aquifer and well parameters, such as:
— permeability of the aquifer,
— radius of influence of pumping,
— pumping rate of a well,
— response of drawdown in an aquifer during pumping,
— skin effect,
— well storage,
— response of recovery in an aquifer after pumping.
2 Normative references

The following referenced documents are indispensable for the application of this document. For dated

references, only the edition cited applies. For undated references, the latest edition of the referenced

document (including any amendments) applies

ISO 14688-1, Geotechnical investigation and testing — Identification and classification of soil — Part 1:

Identification and description

ISO 14689-1, Geotechnical investigation and testing — Identification and classification of rock — Part 1:

Identification and description

ISO 22282-1, Geotechnical investigation and testing — Geohydraulic testing — Part 1: General rules

© ISO 2020 – All rights reserved 1
---------------------- Page: 7 ----------------------
oSIST prEN ISO 22282-4:2020
ISO/DIS 22282-4:2020(E)

ISO 18674-4, Geotechnical investigation and testing — Geotechnical monitoring by field instruments —

Part 4: Piezometers
3 Terms, definitions and symbols
3.1 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 22282-1 and the following apply.

3.1.1
radius of influence of pumping
R(t)

distance, measured from the axis of the well, beyond which the lowering of the piezometric surface of

the groundwater is nil

Note 1 to entry: In a steady-state condition, R(t) is constant, and is thus designated by R .

3.2 Symbols
Symbol Designation Unit
D drilled diameter of the well m
d thickness of the aquifer m
L wetted length of screen of the perforated pipe placed in the well m
Q flow rate m /s

Q discharge rate, assessed pumping discharge at the end of the well preparation m /s

Q discharge of the pumping test m /s
R radius of influence under steady-state conditions m
R(t) radius of influence at time (t) m
S storage factor —
T transmissivity m /s
t time s
v velocity —
a slope of the line that characterizes the drawdown in the well —

b ordinate at the origin of the line that characterizes the drawdown in the well —

c conventional drawdown unit of the preliminary pump discharge —

d size which may be interpolated from the grading curve, of the square sieve mesh of side d —

for which the weight percent of undersize is equal to N percent

e distance between the bottom of the well and the surface of the unconfined groundwater at m

rest in an aquifer
k horizontal permeability coefficient m/s
Δh drawdown of the water level in the well m
Δh' drawdown of the water level in the well after 2 h m

Δh drawdown of the water level in the well, set during the preliminary test and not to be m

exceeded
Δh maximum drawdown of the water level in the well during the pumping test m
max
4 Equipment
Conducting a pumping test requires the following equipment and instruments:
a) a test well and piezometers (see ISO 18674-4);
2 © ISO 2020 – All rights reserved
---------------------- Page: 8 ----------------------
oSIST prEN ISO 22282-4:2020
ISO/DIS 22282-4:2020(E)

b) a pump and associated pipework capable of pumping from the test well. The pumps shall be

equipped with a suitably long discharge pipe so that the water from the pump is discharged

sufficiently far away so that it does not affect the test area. The capacity of the pump shall be

sufficient to extract from the well a discharge at least equal to that corresponding to that estimated

to achieve the maximum planned drawdown;

NOTE Pumping tests are commonly carried out using electric submersible pumps, installed within the

test well. However, depending on conditions, pumping tests can also be carried out using suction pumps

located at the surface, airlift equipment, or special dewatering equipment such as well points or eductors.

c) a system for regulating and measuring the discharge (m /s). Devices for measuring the discharge

rate shall be suitably calibrated and shall be accurate for a range of flow rates anticipated during

the test;

d) a system for measuring the water level in the test well and piezometers. The turbulence in the test

well caused by pumping shall be considered; the devices shall be capable of measuring water levels

over the range of drawdowns anticipated during the test;
e) a time measuring and/or recording device, reading in seconds.
5 Test procedure
5.1 Test preparation
5.1.1 General

When preparing a pumping test, there are a number of things to investigate and consider in advance,

such as:

— basic information on the ground and groundwater conditions according to ISO 22282-1;

— the required drawdown and/or the required discharge rate during the test;

— the discharge point for the pumped water and its location relative to the test well;

— the duration of the test.
5.1.2 Determining the discharge rate for the pumping test

The discharge rate Q must be estimated to ensure that the test well can yield sufficient water, to allow

a pump of appropriate capacity to be selected, and to ensure that the discharge can be accepted at the

agreed disposal point.
The discharge rate can be estimated by one or more of the following methods:
— based on the purpose of the test and experience of local conditions;

— by theoretical assessment of the well capacity, according to the method described in Annex B;

— by analysis of information from the preliminary pumping phase, according to the method described

in Annex B.
5.2 Arranging the disposal of discharge water

The disposal of discharge water shall be in accordance with relevant rules and regulations.

If the discharge water is not disposed of via an engineered sewer network, it shall be disposed of at

sufficient distance from the test well that it will not have a significant impact on the observed pattern

of groundwater lowering.
© ISO 2020 – All rights reserved 3
---------------------- Page: 9 ----------------------
oSIST prEN ISO 22282-4:2020
ISO/DIS 22282-4:2020(E)
5.3 Executing and equipping the well
5.3.1 Design of the test well

The test well shall be designed to satisfy the following criteria (see Figure 1):

— of sufficient depth to penetrate below the groundwater level in the strata of interest. If the test well

does not fully penetrate the aquifer, it shall penetrate the saturated part of the aquifer to a depth of

at least 25 times the well screen diameter with a minimum of 3 m;

— of sufficient drilled diameter to accommodate the necessary filter materials and well screen of

sufficient diameter to accommodate pumping equipment of adequate capacity to achieve the

required discharge rate;

— with sufficient length and capacity of well screen to ensure that the required discharge rate can be

achieved;

— to have appropriate filter material to ensure that the discharge water contains an acceptably low

sediment content to avoid the risk of pump damage and ground settlement as a result of the removal

of fine particles from the soil. Where the well is constructed in a stable rock, it may be possible to

construct a test well without the need for filter material.

The filter material shall be a highly permeable granular material of closely controlled particle size, and

be formed of grains of inert minerals in relation to the aquifer groundwater chemistry (e.g. quartz,

feldspar). In granular soils, the filter's grading curve shall satisfy the double inequality:

5 d ≤ d ≤ 5 d
15 soil 15 filter 85 soil

where d designates the characteristic size of the filter or of the ground in place, such that the mass of

the soil fraction passing through a sieve with a square mesh of side d represents N % of the total mass

of material.

In fine grained soils or where the well screen is equipped with a geotextile mesh designed to act as a

filter, the filter material’s purpose is to backfill the annular space between the outside of the well screen

and the borehole wall. In those circumstances the filter media should be highly permeable coarse sand

or fine gravel, with a permeability coefficient at least 100 times that of the soil or rock being tested.

The thickness of the annular space for the filter pack shall be at least 50 mm. The inner diameter of the

test well shall be selected according to the purpose.
4 © ISO 2020 – All rights reserved
---------------------- Page: 10 ----------------------
oSIST prEN ISO 22282-4:2020
ISO/DIS 22282-4:2020(E)
Key
1 well screen (slotted tube) 7 plain tube
2 filter material (filter pack) 8 device for measuring the water level
3 submersible pump 9 base of the screen
4 borehole casing L filter length
5 tube for measuring the water level D drilled diameter of the well
6 sealing plug
Figure 1 — Test well equipped for a pumping test — Example
© ISO 2020 – All rights reserved 5
---------------------- Page: 11 ----------------------
oSIST prEN ISO 22282-4:2020
ISO/DIS 22282-4:2020(E)
5.3.2 Installation procedure

The test well shall be constructed in a similar way to piezometers in accordance with ISO 22475-1.

Great care shall be taken when installing the well materials. Particular attention shall be paid to the

following:

— The well screen shall be lowered into the borehole to the specified level and shall be installed

centrally in the well, with the top and bottom of the screen located at the design level. Care shall

be taken that the joints of the screen and casing do not leak, and that the screen and casing are

installed vertically and straight.

— If necessary, filter material shall be inserted in the annular space between the screen and the

temporary casing (or borehole wall). The filter material shall be placed progressively in stages to

reduce the risk of a blockage in the annular space. The filter material shall preferably be placed via

a tremie pipe.

— If necessary, a sealing plug of low permeability material (such as bentonite) shall be created in the

annular space between the borehole wall and the well casing immediately above the filter material.

The purpose of the sealing plug is to prevent infiltration of surface water, or water from other

aquifers, into the well screen.
5.3.3 Preparation of the well

Prior to the pumping test the well shall be developed to increase the permeability of the soil around the

shell by washing, and to remove any drilling residues and mobile soil particles that could be entrained

by the water flow into the well. Such particles could clog the filter and damage the test pump.

Development shall be carried out by means of pumping. Possible methods include airlifting or pumping

using a robust pump that is not damaged by the presence of particles in the discharge water. If airlift

pumping is used, care shall be taken to avoid injecting air into the ground, as air bubbles in the ground

can affect the permeability.

Other methods for well development may be used in combination with pumping, including:

— jetting with water inside the well screen;

— surging or swabbing inside the well screen to induce water flow into and out of the well;

— chemical treatment (e.g. use of acids in carbonate rocks).
5.4 Executing and equipping the piezometers
5.4.1 Installation procedure
Piezometers shall be installed in accordance with ISO 22475-1.

The piezometer tubes shall be installed at such a depth that the influence of the test well can be observed

and recorded adequately. Where possible, the piezometer closest to the test well shall be located at the

same depth as the bottom of the test well.
5.4.2 Preparation of piezometers

Before commencement of the test, piezometers shall be cleaned in accordance with ISO 22475-1. The

water level in the piezometers shall be measured for a period before and after the test in order to find

any natural variations in the groundwater level. Their response time shall be checked by watching the

water rise in the piezometer tube. The period of monitoring depends on the nature of the aquifer and

the purpose of the pumping test.
6 © ISO 2020 – All rights reserved
---------------------- Page: 12 ----------------------
oSIST prEN ISO 22282-4:2020
ISO/DIS 22282-4:2020(E)
5.5 Execution of the test
5.5.1 General
The test comprises up to four phases:
— a pre-pumping phase to monitor the undisturbed groundwater levels;
— a preliminary pumping phase to determine the discharge from the pumping test;
— the pumping test phase;
— the post-pumping test phase to monitor recovery of groundwater levels.
5.5.2 Pre-pumping monitoring

Prior to commencement of the pumping phase of the test, water levels in the test well and piezometers

shall be monitored to determine natural groundwater levels.

NOTE The duration of the pre-pumping phase depends on the purpose of the test and local conditions.

Typical durations of pre-pumping monitoring are between one day and ten days. Longer periods of pre-pumping

monitoring are necessary when groundwater levels are subject to tidal or other variations.

5.5.3 Preliminary pumping phase

Prior to the main pumping test a short period of pumping shall be carried out to test the equipment.

NOTE Suitable durations for the equipment test are between 15 min and 2 h.

During the preliminary pumping phase the correct functioning of pumps, control systems, valves, flow

measurement devices and water level measurement devices shall be checked. Discharge pipe work shall

be checked for leaks. Any corrective action deemed necessary shall be taken prior to commencement of

the pumping test.

For large-scale or complex pumping tests, the preliminary pumping phase can be used to provide

information on discharge rate and drawdown to assist in determination of discharge rate for the

pumping test (see Annex B).
5.5.4 Pumping test

The pumping test shall not be started until water levels in the test well and the piezometers have

stabilized following the preliminary pumping phase.
The pumping test can comprise:

— a variable rate test. This type of test involves pumping the test well in a step-wise fashion, either

increasing or decreasing, up to the maximum capacity of the test well or the pump. A variable rate

test can be used to assist in determination of the discharge rate for a constant rate test;

and/or

— a constant rate test. This type of test involves pumping the test well at a constant rate for the

duration on the test.

If the pumping test comprises a variable rate test followed by a constant rate test, there may be a period

of post pumping monitoring following the end of the variable rate test. In this case, the period between

the end of the variable rate test and the beginning of the constant rate test should be long enough to

allow water levels to stabilize.
© ISO 2020 – All rights reserved 7
---------------------- Page: 13 ----------------------
oSIST prEN ISO 22282-4:2020
ISO/DIS 22282-4:2020(E)

Whenever the discharge is started or changed, the change in pumping rate shall be carried out rapidly.

At the start of the pumping test the discharge rate shall be stabilized within 2 min after starting the

pumping.
The time at the start of the test is defined as t = 0.

During the pumping test measurements of water level shall be made according to the requirements

of the purpose of the test and the ground conditions. In general, measurements shall be taken more

frequently at the start of the pumping test, or when flow rate has been changed during a variable rate

test, when water levels are likely to be changing rapidly. During the later stages of a pumping test, when

water levels are changing more slowly, readings can be taken less frequently.

The following time increments between readings should be used unless alternative time increments

can be justified based on the purpose of the test and the ground conditions. If the groundwater levels in

the test well and piez
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.