ISO/TS 18671:2026

• Abstract:

  This document provides test methodologies for assessing the compatibility of wet wipes and moist toilet tissue with the wastewater collection and treatment systems, and it specifies appropriate labelling for products deemed incompatible. The products that this document is applicable for are wet wipes and moist toilet tissue. This document does not cover: toilet paper as defined and covered by other ISO documents; chemical toilets or compost toilets that are not connected to sewer systems; macerator and vacuum sewer systems; water soluble polymers.

• Status: Published
• Publication Date: 12-Aug-2026
• ICS: 85.080.20 - Tissue paper
• Technical Committee: ISO/TC 224 - Drinking water, wastewater and stormwater systems and services
• Drafting Committee: ISO/TC 224 - Drinking water, wastewater and stormwater systems and services
• Current Stage: 6060 - International Standard published
• Start Date: 13-Aug-2026
• Due Date: 10-Nov-2025
• Completion Date: 13-Aug-2026

Overview

ISO/TS 18671 establishes test methodologies for assessing the compatibility of wet wipes and moist toilet tissue with wastewater collection and treatment systems, as well as requirements for appropriate labelling. This technical specification is essential for manufacturers, regulators, and stakeholders involved with disposable sanitary products designed for bathroom use. The standard aims to address the growing concern over blockages and operational issues in sewer systems caused by products that are not designed to degrade or disintegrate appropriately after flushing.

ISO/TS 18671 applies to wet wipes and moist toilet tissues intended for toilet disposal, setting out how to evaluate their impact on plumbing, wastewater transport, and treatment infrastructure. It also provides guidance on consistent labelling, helping to inform consumers and reduce the risk of sewer blockages and environmental harm. The document is not applicable to dry toilet paper, chemical or compost toilets, macerator/vacuum sewer systems, or water-soluble polymers.

Key Topics

• Test Methodologies: The standard identifies internationally used methodologies (such as GD4 and UK WIS) for testing whether wet wipes and moist toilet tissue disintegrate, degrade, and move safely through household and municipal wastewater systems.
• Product Scope: Focuses exclusively on wet wipes and moist toilet tissue, excluding dry toilet paper and products for non-sewered systems.
• Wastewater System Elements Assessed:
  • Toilet and drainline clearance
  • Wastewater transport (sewers and pumps)
  • Wastewater treatment plant compatibility
  • Biodegradation and biodisintegration
• Labelling Requirements: Specifies when and how to use labels indicating if a product is compatible or incompatible with flushing, helping manufacturers provide clear information and comply with local or national standards.
• Environmental Considerations: Highlights the need to evaluate potential environmental impacts, including toxicity, bioaccumulation, and persistence of product components if they enter water treatment or receiving environments.
• Testing Variables: Discusses testing parameters such as duration, speed, water volume, temperature, and sieve size – all of which affect product disintegration outcomes.

Applications

ISO/TS 18671 has practical applications in several sectors, including:

• Manufacturing: Helps producers of wet wipes and moist toilet tissue design products that pass relevant compatibility tests, reduce the risk of blockages, and meet market access requirements.
• Product Labelling: Provides the basis for clear and standardized consumer labelling on flushability, ensuring end-users are informed about appropriate disposal practices.
• Wastewater Utilities: Supports utilities and municipal authorities in reducing maintenance costs and environmental risks tied to non-flushable items entering sewer systems.
• Regulations and Trade: Enables regulators and policymakers to harmonize requirements for "flushable" claims, supporting consumer protection and environmental stewardship.
• Retail and Distribution: Assists retailers in verifying the claims of flushable products and ensuring labelling is consistent with ISO guidance and national regulations.

Related Standards

Several ISO and national standards relate to the scope and content of ISO/TS 18671, including:

• ISO 24513: Vocabulary for drinking water, wastewater, and stormwater systems
• ISO/TR 24524: Guidance on drainlines and sewerage system components
• GD4 Test Methodology: Referenced in several countries and foundational to many flushability standards
• UK Water Industry Specification (WIS): Specific methodology for the UK market
• Local/Regional Guidelines: Specifications in Belgium, Spain, China, Australia, and New Zealand, often based on or derived from international methodologies

Practical Value

Adopting ISO/TS 18671 enables manufacturers and regulators to align with best practices for environmental safety, system efficiency, and consumer communication. It provides a clear framework for testing, certification, and labelling, promoting harmonization of "flushable" claims globally. This benefits wastewater infrastructure, reduces costly maintenance, and informs responsible consumer behavior regarding disposable hygiene products.

Technical
Specification
ISO/TS 18671
First edition
Test methodologies for assessing
2026-08
the compatibility of wet wipes
and moist toilet tissue with
the wastewater collection and
treatment systems, and appropriate
labelling
Méthodologies d'essai pour évaluer la compatibilité des lingettes
humides et du papier hygiénique humide avec les systèmes de
collecte et de traitement des eaux usées, et étiquetage approprié
Reference number
© ISO 2026
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or ISO’s member body in the country of the requester.
ISO copyright office
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Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Framework . 3
4.1 Context .3
4.2 Domestic plumbing and drainline systems .4
4.2.1 Toilets .4
4.2.2 Drainlines .4
4.3 Wastewater transport systems .4
4.3.1 General .4
4.3.2 Sewers .4
4.3.3 Pumping stations .5
4.4 Wastewater treatment systems .5
4.4.1 General .5
4.4.2 Settling .5
4.5 Biodegradation and biodisintegration .5
4.6 On-site domestic wastewater systems .6
4.7 Environment .6
5 Testing methodologies . 6
5.1 General .6
5.2 Domestic plumbing and drainline systems .7
5.2.1 General .7
5.2.2 Toilet clearance test .8
5.2.3 Drainlines .8
5.2.4 Household pump test .8
5.3 Wastewater transport networks .8
5.3.1 General .8
5.3.2 Disintegration testing methods .9
5.3.3 Disintegration testing method considerations .9
5.3.4 Municipal sewage pump test .10
5.4 Wastewater treatment systems .10
5.4.1 General .10
5.4.2 Settling .10
5.4.3 Biodegradation and biodisintegration tests .11
6 Labelling .12
6.1 General . 12
6.2 When to apply labelling . 12
6.3 Packaging . 12
6.4 Location on the packaging . 12
6.5 Geometric shape and colour . 13
6.6 Size . 13
6.7 Advisory text . 13
Annex A (informative) Examples of labelling . 14
Annex B (informative) Summary of current test methods .15
Bibliography .25

iii
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
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The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
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related to conformity assessment, as well as information about ISO’s adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 224, Drinking water, wastewater and
stormwater systems and services.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
Introduction
Flushing of products that are incompatible with sewerage networks can contribute to:
— blockages in home plumbing and smaller sewer pipes, and blockages in pumps;
— increased screening of solids for solid waste disposal;
— increased burden for treatment processes both on-site and at the municipal level, with non-degradable
materials which can lead to further downstream environmental impacts;
— increased risk of sewer blockages at reduced sewer flows.
Consistent labelling and education to inform consumers of proper disposal of products is important to
help reduce adverse effects on wastewater collection and treatment systems. Application of this document
presupposes that not only the producers but also all the concerned parties involved in export, retail or
consumption are aware of the legislation and regulations pertaining to wet wipes and moist toilet tissues.
This document provides recommendations regarding:
— labelling and the use of a symbol to be used with non-flushable product packages indicating incompatibility
with the wastewater system;
If a product is compatible with a wastewater collection and treatment system the producer may use
a suitable symbol conforming with relevant local or national standards, or in compliance with legal
requirements of the targeted country or region.
— the use of any of five different available methodologies worldwide for assessing product compatibility
with the wastewater collection and treatment system and subsequent labelling.
This document describes currently published test methodologies for assessing compatibility of products
with wastewater networks. Each methodology comprises different methods that must be used to determine
wastewater network compatibility. It is important to note that the methodologies are stand alone, and the
individual methods are not designed to be interchanged. They are outlined in Annex B, detailing where
they are being used and differences in testing approach, enabling the reader to select whether a particular
methodology is more relevant to their geographical region.

v
Technical Specification ISO/TS 18671:2026(en)
Test methodologies for assessing the compatibility of wet
wipes and moist toilet tissue with the wastewater collection
and treatment systems, and appropriate labelling
1 Scope
This document provides test methodologies for assessing the compatibility of wet wipes and moist toilet
tissue with the wastewater collection and treatment systems, and it specifies appropriate labelling for
products deemed incompatible. The products that this document is applicable for are wet wipes and moist
toilet tissue.
This document does not cover:
— toilet paper as defined and covered by other ISO documents;
— chemical toilets or compost toilets that are not connected to sewer systems;
— macerator and vacuum sewer systems;
— water soluble polymers.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements 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 24513, Service activities relating to drinking water supply, wastewater and stormwater systems —
Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 24513 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
biodegradation
degradation due to the biological environment
[SOURCE: ISO/TR 19057:2017, 3.2, modified — Note 1 to entry was removed.]
3.2
disintegration
breaking of material into small pieces in water under specified conditions
[SOURCE: ISO 12625-17:2021, 3.1, modified — “process that is characterized by a material breaking” was
changed to “breaking of material”.]

3.3
methodology
collection of standards, procedures and supporting methods that define the complete approach to the
development of a product or system
[SOURCE: ISO/IEC 21827:2008, 3.22]
3.4
mineralization
decomposition of organic matter or organic substances into carbon dioxide, water and the hydrides, oxides
or other mineral salts
[SOURCE: ISO 11074:2025, 3.3.19, modified — “final stage of the biodegradation” was changed to
“decomposition”.]
3.5
moist toilet tissue
moist toilet paper
prewetted nonwoven material intended for sanitary use after using the toilet
Note 1 to entry: Products labelled as “moist toilet paper” are made from nonwoven material and are not considered as
“toilet paper” for the purpose of this document.
[SOURCE: ISO 12625-1:2019, 3.60, modified — The term was changed from “toilet paper” to “moist toilet
tissue”; in the definition, “tissue paper” was changed to “prewetted nonwoven material”.]
3.6
persistent
existing or remaining in the same state for an indefinitely long time
[SOURCE: ISO/TR 18307:2001, 3.111, modified — The admitted terms “persistence” and “enduring” were
removed.]
3.7
plastic
solid material which contains, as an essential ingredient, one or more high molecular mass polymers and
which is formed (shaped) during either manufacture of the polymer or the fabrication into a finished product
by either heat or pressure, or both
Note 1 to entry: In different regions there are legal definitions of plastic(s). Users of this document are advised to
check the definition of plastic in the geographical or jurisdictional region where products are marketed.
[SOURCE: ISO 21070:2017, 3.2.11 modified — The original Notes to entry were removed, and a new note was
added.]
3.8
toilet paper
bathroom tissue
bath tissue
dry toilet paper
tissue paper intended for sanitary use after using the toilet
Note 1 to entry: Products labelled as “moist toilet paper” are often made from nonwoven material and are not
considered as “toilet paper” for the purpose of this document.
[SOURCE: ISO 12625-1:2019, 3.60, modified — In the note to entry, “are not in the scope of this document”
was changed to “ are not considered ‘toilet paper’ for the purpose of this document”.]

3.9
transit time
sewer residence time
in-sewer travel time
wastewater residence time
amount of time a given volume of wastewater resides in a sewer system between a designated beginning
and end point
Note 1 to entry: Sewer systems include pumping stations and treatment plants.
3.10
toilet
water closet
WC
fixed receptacle into which a person may urinate or defecate, typically consisting of a large bowl connected
to a cistern for flushing
[SOURCE: ISO/TR 24524:2019, 3.7, modified — “water closet” and “WC” were added as admitted terms.]
3.11
wet wipe
small piece of premoistened or prewetted material which is conceived, designed and placed on the market
for single-use (disposable) and intended for personal care or domestic use
Note 1 to entry: Personal care is intended to be used for hygiene purposes, these include cleansing and caring of skin
of both human adults and babies e.g. cosmetics, baby wipes, intimate care wipes.
Note 2 to entry: A domestic use wet wipe is intended to be used in domestic premises. These include wet wipes used
for household cleaning purposes, e.g. wipes used to clean.
Note 3 to entry: Prewetted wipes typically contain an impregnation liquid which has been added to the wipe before it
is placed on the market.
Note 4 to entry: Adapted from Reference [11].
4 Framework
4.1 Context
References [9] to [20] were the basis for drafting this document. These documents are current national
standards, international guidelines and specifications which have been adopted in some regions.
Table B.1 provides an overview of the various test methodologies in use, when they were published,
their relevance and the regions or countries where they are being applied. When selecting a particular
methodology described in Annex B, based on the aspects outlined in this document, users should follow the
methodology as prescribed. Test methods from different methodologies should not be interchanged. The key
elements of a wastewater system to be considered in test methods for evaluating products suitable for toilet
disposal are described in ISO/TR 24524. The design, operation and serviceability of sewerage facilities can
vary widely from country to country.
The key elements are:
a) toilets;
b) drainlines (including domestic pumps);
c) wastewater transport systems (including municipal pumps) and screening systems;
d) treatment processes;
e) environment.
The wastewater system comprises elements (a) to (d). Material that enters wastewater treatment plants can
either be removed via degradation, integration into the semi-solid phase, volatilized into gaseous form or
released in the treated effluent discharged from the wastewater treatment plant to receiving environments.
Products disposed into wastewater systems can also reach receiving environments without treatment. From
time to time, sewers overflow to the environment for a multitude of reasons. Given that products disposed
into wastewater systems have the potential to cause environmental harm if untreated, products should be
[7]
evaluated for environmental and treatment plant compatibility.
4.2 Domestic plumbing and drainline systems
4.2.1 Toilets
The purpose of a toilet is to dispose of human excreta (i.e. urine, menses, vomit and faeces) by using water to
flush it through a drainline to another location for disposal, thus maintaining a separation between humans
and their waste. Any product discharged via a toilet should not adversely affect the intended operation of
[7]
the toilet. The typical flush volume for new toilets varies from 2 l to 6 l.
4.2.2 Drainlines
Drainline design, configuration, construction and maintenance can impact the ability of waste to pass
through a drainline. Typically, material flushed from a toilet into a drainline moves along the drainline with
water from toilet flushing. Failure of flushed product to exit the drainline can result in blocked plumbing
within the property, blocked external drainage pipelines, the generation of foul odours or the product
drying out and adhering to the pipe surface. Products intended to be discharged via a toilet should clear the
drainline and reach the sewer without adversely affecting the operation of the drainline.
4.3 Wastewater transport systems
4.3.1 General
The design, layout and configuration of wastewater transport systems vary among and within countries
due to various factors including regulation, population density, system age, geographic and topographic
features, and climatic conditions.
4.3.2 Sewers
4.3.2.1 Wastewater network hydraulics and solids transport
The purpose of the sewer is to receive discharges from drainlines and convey the discharges from drainlines
to wastewater treatment systems. Flow in wastewater conveyance systems typically occurs via gravity
flow, pumped flow, vacuum pressure or a combination of these. Flow can be intermittent or continuous
and is dependent on the sewer design, wastewater flow conditions influenced by either rainfall or peak
discharge usage, or both. In small diameter pipes (less than 225 mm), there is an elevated risk that products
introduced into the sewer system can become snagged on pipe imperfections or tree roots, thus resulting in
pipe blockages.
4.3.2.2 Wastewater transport network velocity
Wastewater velocities vary significantly as a result of a range of factors including sewer design, climatic
conditions, topography and volume. In general, sewers are designed to achieve a velocity sufficient to
[14]
transport solids to prevent deposition and decomposition in the sewer.
4.3.2.3 Transit time
Surveys of sewer transit times indicate the typical duration to the first screen or pump is between 30 minutes
and 6 hours, although it can be less than 10 minutes for densified residential areas and it can reach several

[15][23][24][25]
days. Transit time should be considered when selecting tests methodologies. Local conditions
can require a higher minimum cross-sectional velocity value or a minimum sewer slope value.
4.3.2.4 Temperature
The temperature of the wastewater can vary depending on geographic location and season. It can typically
[7]
range from 5 °C to 30 °C.
4.3.3 Pumping stations
Pumps are commonly used to facilitate wastewater transport where this cannot be achieved by gravity
alone. They are typically utilized within the transport system from the point of discharge from the customer
property to the nearest point where gravity flow is possible or to the treatment plant. Screens or grinders
can be installed ahead of the pumps or other downstream infrastructure, including overflow outlets, and
immediately before the influent point of the treatment system to protect equipment from becoming blocked.
Products greater than a certain size can foul screens, resulting in an elevated load of solid waste to landfill,
[7]
increased maintenance or potential blockages leading to sewer overflows and flooding.
Solids transported in sewers can accumulate and cause pump malfunction in pumping stations before
reaching wastewater treatment plants. Such events are observed worldwide.
4.4 Wastewater treatment systems
4.4.1 General
A product that enters a wastewater treatment plant should not unduly affect the ability of that plant to meet
legislated or licence conditions, and should not result in additional operational costs, nor adversely impact
the environment. The effluent discharged from wastewater treatment plants should not pose an increased
[7]
environmental risk.
4.4.2 Settling
The majority of solids that enter a wastewater treatment plant are removed through initial screening and
subsequent settling throughout the treatment process. The rate of settling within a wastewater treatment
plant is measured by the settling velocity. The settling rate of a product is affected by particle size and
density, along with system design, operation and capacity. A settling test should be used to evaluate the
[7]
settling rate for products.
4.5 Biodegradation and biodisintegration
The purpose of wastewater treatment is to separate and treat the solids and clean the incoming wastewater
to a level suitable for discharge or reuse. Organic wastewater solids are typically broken down biologically
using aerobic or anaerobic digestion processes. The dewatered digested sludge solids (also called biosolids)
can then be incinerated, landfilled or applied to the land.
To evaluate if a product is compatible with biological wastewater treatment process and can be fully treated
such that no product is recognizable in the effluent leaving municipal wastewater treatment systems or
[23]
in the post-treatment products of treatment sludges, laboratory tests should be utilized to evaluate the
potential of products to break down biologically under aerobic and anaerobic conditions.
These tests can also be utilized to determine if a product contains materials that do not degrade biologically
in aerobic or anaerobic conditions and are therefore likely to be discharged in the wastewater effluent or
persist in biosolids which could be subsequently applied to the land, or discharged directly to a receiving
environment.
4.6 On-site domestic wastewater systems
On-site domestic wastewater systems (ODWS) are widely used throughout the world to collect, treat,
discharge, disperse or reuse domestic wastewater in areas where centralized sewerage systems are not
viable or not currently available. An ODWS is often a self-contained unit designed to collect, treat and
discharge, disperse or reuse wastewater. The testing protocols proposed in this document do not distinguish
between ODWS and centralized treatment systems. However, methodologies take into account aspects of
different types of ODWS, including more basic systems.
For ODWS, a methodology that includes a toilet and drainline test, a domestic pump test, a settling test and
anaerobic and aerobic biodisintegration tests should be utilized to evaluate if the product can be transported
with wastewater solids through the toilet and downstream pipework and domestic pumps, if the product
will settle inside the tank, and if it will be mineralized.
4.7 Environment
For products covered by the scope of this document, consideration should be given to environmental safety,
including assessment of toxicity, bioaccumulation and persistence of their components.
5 Testing methodologies
5.1 General
Evaluation of products for compatibility with wastewater systems follow two predominant testing
[18] [24] [18]
methodologies. The two primary models are GD4 and the UK WIS . The GD4 model has been utilized
with several variations including the removal and modification of test parameters and pass or fail criteria.
The details of these modifications are outlined in this document. The pass-fail criteria for each of those
referenced testing regimes can be found in the documents listed in the bibliography and are summarized
in Annex B. When selecting a methodology to use, it should be adopted in full. The methodologies were
designed to be stand alone. The tests are not designed to be interchanged.
When adopting a methodology for a country or region it is important to understand the sewage facilities of
the country in question and select a methodology that is compatible with those assets.
Figure 1 outlines the approach for determining whether wet wipes and moist toilet tissue are in scope for
this document and the associated labelling.

Figure 1 — Flowchart with steps for assessing the compatibility of wet wipes and moist toilet tissue
with the wastewater collection and treatment systems, and to determine appropriate labelling
NOTE The relevant test methodologies are outlined in Table B.1.
Current available testing methodologies have key similarities. This document identifies their differences
and options for applying them.
[18] [24]
Both GD4 and the UK WIS evaluate performance of products in infrastructure from the toilet through
residential plumbing, wastewater transport infrastructure and wastewater treatment. The local standards
[18]
developed for countries including Belgium, Spain, China, Australia, and New Zealand are all based on GD4.
[18]
The IWSFG is also based on GD4. Several of these have modifications for operating conditions and pass or
fail criteria. The reason for these modifications is to address different perspectives regarding protection of,
and product compatibility with, wastewater systems.
5.2 Domestic plumbing and drainline systems
5.2.1 General
A product discharged via a toilet should not adversely affect the intended operation of the drainline or
sewerage system. Details of the test methods currently in use for domestic plumbing and drainline systems
are provided in Tables B.2 and B.3.

5.2.2 Toilet clearance test
The product should not block or allow the toilet to surcharge (overload) or overflow. The purpose of toilet
[18]
clearance testing is to assess that products do not adversely affect toilet operation. GD4 and its variants
[24]
integrate the drainline clearance test with the toilet bowl clearance test whereas the UK WIS separates
[18]
toilet testing from the drainline clearance test. For GD4 the material flushed down the toilet includes
simulated faecal material, toilet paper and the tested product to simulate user behaviour (4 people), whereas
[24]
the UK WIS uses only the tested product alone.
[18]
The GD4 method allows the single use of a plunger, wherein one replicate is allowed to be plunged, while
[18]
modifications to this have been made in methodologies that incorporate the GD4 toilet and drainline test.
5.2.3 Drainlines
5.2.3.1 Drainline clearance test
A drainline clearance test should be used to confirm that a product exits the drainline without causing
[18] [24]
backup of water and materials. The intent of the drainline clearance tests of GD4 and the UK WIS are
[18]
similar, i.e. that product moves along the drainline and exits within a certain number of flushes. The GD4
test methodology is adjustable for different toilet flush volumes and to account for the slope of the drainline.
The details of typical international variations for these parameters are outlined in ISO/TR 24524.
[18]
GD4 assesses the movement of material down the drainline using a calculation called the centre of mass.
This establishes that the material is moving down the drainline, accounting for pieces if the material starts
to separate as it moves. The centre of mass is the weighted average position of the material (mass weighted
[9]
centre). It has been replaced by centre of movement in AS/NZS 5328, which is the average position of the
material. The material flushed down the drainline includes simulated faecal material, toilet paper and the
tested product in a given sequence to simulate the behaviour of users (4 people) using the toilet.
5.2.3.2 Drainline disintegration test
In order to assess if a product is capable of disintegrating sufficiently, to an extent that minimises risk
of blockage to a pipe or pumps, as it passes through the drainline, the UK has developed a drainline
disintegration test. This test has not been adopted elsewhere as the tests associated with the disintegration
in alternative test methods address this concern.
5.2.4 Household pump test
[18]
GD4 includes a household pump test in addition to the toilet and drainline clearance test. The household
[18]
pump test is not necessarily part of local requirements based on GD4. A household pump test (see
Clause B.2) should be used to assess the compatibility of a product with household sewage pump systems
to assess that the product does not clog, accumulate within or otherwise interfere with normal system
operation. The test seeks to simulate the conditions of operation for a household pump by using a typical
household wastewater pump (Table B.2) in a container connected to a discharge pipe under laboratory
conditions.
5.3 Wastewater transport networks
5.3.1 General
Disintegration is a primary test used to assess the compatibility of a product with wastewater transport
systems including pumping systems and downstream pipework. For this purpose, a disintegration test is
[18]
included in all test methodologies and supplemented by a municipal pump test in GD4 and some of its
variants. Details of the test methods currently in use are provided in Table B.5.

5.3.2 Disintegration testing methods
[24]
There are two tests available, the slosh box disintegration test and the UK WIS sewer system shake flask
test. Both test methodologies have been developed through laboratory simulation of forces similar to sewer
networks and observation of the relative disintegration of product within artificial and live sewer networks.
Variations to the disintegration test parameters have been developed based on laboratory testing within
different regions. A detailed description of the approach and considerations for differences in the test
parameters are provided below. These considerations should be taken into account when selecting a
methodology.
There are five tests currently referenced by national and international standards, guidelines and
specifications relating to the characterization of physical disintegration to determine if a product is suitable
for disposal via toilet flushing (Table B.5):
[19] [22] [13] [10]
a) Slosh box disintegration test variations – GD4, IWSFG, Spain, China, and Australia and New
[9] [12]
Zealand. This also includes the rapid mechanical disintegration test ‒ Belgium based on GD3.
[24]
b) Disintegration in the drainline test (UK WIS, Annex C ) and disintegration in the sewer test (UK WIS,
[24]
Annex E ). Both UK disintegration tests are to be performed to assess one product.
5.3.3 Disintegration testing method considerations
Considerations in applying these test methods are:
a) The versions of the slosh box disintegration test referenced in 5.3.2 a) contain multiple independent
variables, the setpoints of which significantly influence test outcomes (refer to Table B.5 for details):
1) test duration (measured in minutes or hours);
2) speed [the speed of the reciprocation of the slosh box or the speed of the rotation of the shake flask,
measured in revolutions per minute (r/min)];
3) volume of media [measured in litres (l)];
4) sieve opening size [the size of the sieve utilized for sample recovery after testing, measured in
millimetres (mm)];
5) pre-treatment duration [rinsing of samples, or static conditioning of a sample in open air prior to
testing, measured in minutes (min)];
6) temperature [measured in degrees Celsius (°C)].
b) The interaction of the independent variables (identified as “Parameter” in Table 1) directly impacts test
outcomes and variability.
Table 1 — General impact of individual test parameters on test outcomes
Parameter Impacts
Inclusion of a pre-conditioning step that introduces additional time for a product to
Preconditioning
lose strength prior to testing.
Speed Lower speed introduces less turbulence during testing.
Shorter test duration reduces the amount of force experienced by the sample, which is
Duration
directly related to time under testing.
Larger volume of water reduces the amount of turbulence generated during each artic-
Media Volume
ulation.
Temperature Lower temperature can reduce the amount of sample disintegration.
Small sieve opening size requires the sample to reach smaller dimensions in order to
Sieve opening size
pass through the sieve.
The transit time varies depending on the wastewater network design. Therefore, consider transit time and
other factors when applying the disintegration test.
c) When considering the slosh box disintegration tests for evaluating physical disintegration, a comparison
between versions indicates the IWSFG version will produce less disintegration than the AS/NZS version
[18]
which in turn will produce less than the INDA/EDANA GD4 version, which in turn will produce less
[17]
than the INDA/EDANA GD3 version .
As noted in 5.3.2 b), the interaction of independent variables can be significant. The screening tests
developed to date are intended to evaluate the disintegration potential of products in a repeatable manner
under mechanical agitation in water that is intended to approximate conditions in a specific portion of sewer
networks.
[24]
d) The UK WIS disintegration in the sewer system shake flask tests differs from the slosh box-based
[24]
disintegration tests in terms of testing equipment, parameters and procedures (Table B.5). The WIS
shake flasks tests contain multiple independent variables, the setpoints of which significantly influence
test outcomes:
1) test duration (measured in minutes or hours);
2) speed (the speed of the reciprocation of the slosh box or the speed of the rotation of the shake flask,
measured in revolutions per minute [r/min]);
3) perforated plate sieve opening size (the size of the sieve utilized for sample recovery after testing,
measured in millimetres [mm]).
When considering the shake flask disintegration tests for evaluating physical disintegration, a comparison
[24]
between tests indicates the UK WIS Annex C test will produce less disintegration than the Annex E test.
Both the test duration and sieve endpoint are intended to reflect conditions within the wastewater transport
systems across the United Kingdom.
The interaction of independent variables within and among the disintegration tests can be significant.
As designed, the screening tests developed to date are intended to evaluate the disintegration potential
of products in a repeatable manner under mechanical agitation in water that is intended to approximate
conditions in a specific portion of sewer networks.
5.3.4 Municipal sewage pump test
A municipal sewage pump test is used to determine the compatibility of products with municipal sewage
pumping systems (Table B.9). The test employs a small municipal pump typically used in municipal
wastewater systems as a realistic worst-case scenario. The municipal sewage pump test measures pump
power increases and is not included within all methodologies.
5.4 Wastewater treatment systems
5.4.1 General
The intent of tests for evaluating compatibility of products with wastewater treatment systems is to assess
that the product is not buoyant and can settle within a short period of time and not resuspend into the water
column. In this case, the settling test should be used. The second suite of tests are screening tests to assess
the ability of the product to biologically degrade under aerobic or anaerobic conditions found in on-site and
municipal wastewater treatment systems. In this case, a biodegradation or biodisintegration test should be
used.
5.4.2 Settling
[18] [24]
This test is relatively consistent between the GD4 (including all variations) and the UK WIS test
[24]
methodologies (Table B.6). The UK WIS evaluates if product components following preconditioning will
[18]
settle, whereas GD4 evaluates the rate of settling for the product.

5.4.3 Biodegradation and biodisintegration tests
5.4.3.1 General
Testing assesses the biodegradation or persistence of products in receiving environments.
Biodegradation or biodisintegration tests can be used to evaluate compatibility with wastewater treatment
and environmental persistence. The use of the product fibre compositional analysis can be considered to
avoid plastic fibres in the product. A manufacturer attestation can be considered to avoid plastic content in
the product.
There are currently several laboratory test approaches to determine the potential for a product to biodegrade
in wastewater treatment, including:
— biodisintegration labora
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