prEN 476

General requirements for components used in drains and sewers

This document specifies general requirements to be respected in product standards for components such as pipes, fittings, inspection chambers and manholes with their respective joints intended for use in drains and sewers inside and outside buildings which operate as gravity systems allowing for a maximum pressure of 40 kPa.
It also specifies general requirements for components used in hydraulically and pneumatically pressurized discharge pipes, drains and sewers.
NOTE 1   Where the term "inside buildings" is used in the context of components fixed inside buildings, it also includes discharge pipes and fittings fixed on external surfaces of buildings
NOTE 2   This document is not a product standard and therefore not intended for the direct evaluation of products.
This document covers components to be used in conveying in a satisfactory manner:
-   domestic wastewater;
-   rainwater and surface water; and
-   other waste waters acceptable for discharge into the system (e.g. industrial wastewater).
This document applies to components of circular and other cross sections.
This document applies equally to components which are factory-made and to those constructed on site, where applicable.
NOTE 3   This document does not apply to components used for trenchless construction according to EN 14457 and for components used for renovation of drains and sewers according to EN 13380.
This document does not supersede the functional requirements of a complete system as defined in EN 752.

Allgemeine Anforderungen an Bauteile für Abwasserleitungen und -kanäle

Dieses Dokument legt allgemeine Anforderungen fest, die in Produktnormen für Bauteile wie Rohre, Formstücke, Kontroll  und Einsteigschächte mit ihren jeweiligen Verbindungen, die für Abwasserleitungen und  kanäle innerhalb und außerhalb von Gebäuden bestimmt sind und die als Schwerkraftsysteme mit maximal 40 kPa betrieben werden, Beachtung finden müssen.
Außerdem legt es allgemeine Anforderungen an Bauteile für hydraulisch und pneumatisch betriebene Abwasserdruckrohre,  leitungen und  kanäle fest.
ANMERKUNG 1   Wird der Begriff "innerhalb von Gebäuden" in Verbindung mit Bauteilen verwendet, die innerhalb des Gebäudes befestigt sind, schließt das auch an den Außenflächen der Gebäude befestigte Abwasserleitungen und Formstücke mit ein.
ANMERKUNG 2   Dieses Dokument ist keine Produktnorm und daher nicht für die direkte Beurteilung von Produkten bestimmt.
Dieses Dokument behandelt Bauteile, die in zufriedenstellender Weise eingesetzt werden, um Folgendes abzuleiten:
-   häusliche Abwässer;
-   Regen  und Oberflächenwasser sowie
-   weitere Abwässer (z. B. industrielles Abwasser), die zur Ableitung in das System zulässig sind.
Dieses Dokument gilt für Bauteile mit kreisförmigem Querschnitt sowie weiteren Querschnitten.
Dieses Dokument gilt gleichermaßen für werkseitig und, soweit zutreffend, für vor Ort hergestellte Bauteile.
ANMERKUNG 3   Dieses Dokument ist nicht auf Bauteile anwendbar, die bei grabenlosem Einbau nach EN 14457 verwendet werden, und nicht für Bauteile, die für die Renovierung von Abwasserleitungen und  kanälen nach EN 13380 eingesetzt werden.
Dieses Dokument ersetzt nicht die funktionellen Anforderungen an ein komplettes System, wie in EN 752 festgelegt.

Exigences générales pour les composants utilisés pour les branchements et les collecteurs d’assainissement

Le présent document spécifie les exigences générales à respecter dans les normes de produits pour les composants tels que les tuyaux, les raccords, les boîtes de branchement ou d’inspection et les regards de visite avec leurs assemblages respectifs, destinés à être utilisés dans les branchements et les collecteurs à l’intérieur et à l’extérieur des bâtiments fonctionnant comme des réseaux à écoulement libre permettant d’admettre une pression maximale de 40 kPa.
Il spécifie également les exigences générales applicables aux composants utilisés dans les canalisations d’évacuation, les branchements et les collecteurs fonctionnant sous pression hydraulique et pneumatique.
NOTE 1   L’expression « à l’intérieur des bâtiments » est employée dans le contexte des composants fixés à l’intérieur des bâtiments et inclut également les canalisations d’évacuation et les raccords fixés aux surfaces extérieures des bâtiments.
NOTE 2   Le présent document n’est pas une norme de produit et n’est donc pas destiné à l’évaluation directe des produits.
Le présent document traite des composants à utiliser pour transporter de manière satisfaisante :
-   les eaux usées domestiques ;
-   les eaux pluviales et les eaux de surface ; et
-   d’autres eaux usées dont l’évacuation dans le réseau est acceptable (eaux usées industrielles, par exemple).
Le présent document s’applique aux composants de section circulaire ou non.
Il s’applique de la même façon aux composants qui sont préfabriqués et aux composants construits in situ, le cas échéant.
NOTE 3   Le présent document ne s’applique ni aux composants utilisés pour la construction sans tranchée selon l’EN 14457, ni aux composants utilisés pour la rénovation des branchements et des collecteurs d’assainissement selon l’EN 13380.
Le présent document ne remplace pas les exigences fonctionnelles d’un système complet telles que définies dans l’EN 752.

Splošne zahteve za elemente za odvod odpadne vode in kanalizacijo

General Information

• Status: Not Published
• ICS: 23.040.05 - Pipeline and its parts for external sewage systems
• ICS: 93.030 - External sewage systems
• Technical Committee: CEN/TC 165 - Waste water engineering
• Drafting Committee: CEN/TC 165/WG 1 - General requirements for pipes
• Current Stage: 4599 - Dispatch of FV draft to CMC - Finalization for Vote
• Due Date: 22-Sep-2021
• Completion Date: 22-Sep-2021
• Ref Project: oSIST prEN 476:2020 - General requirements for components used in drains and sewers

RELATIONS

• Revised: EN 476:2011 - General requirements for components used in drains and sewers
• Effective Date: 25-Sep-2019

Standards Content (sample)

SLOVENSKI STANDARD
oSIST prEN 476:2020
01-oktober-2020
Splošne zahteve za elemente za odvod odpadne vode in kanalizacijo
General requirements for components used in drains and sewers
Allgemeine Anforderungen an Bauteile für Abwasserleitungen und -kanäle
Exigences générales pour les composants utilisés pour les branchements et les
collecteurs d’assainissement
Ta slovenski standard je istoveten z: prEN 476
ICS:
13.060.30 Odpadna voda Sewage water
93.030 Zunanji sistemi za odpadno External sewage systems
vodo
oSIST prEN 476:2020 en,fr,de

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

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oSIST prEN 476:2020
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oSIST prEN 476:2020
DRAFT
EUROPEAN STANDARD
prEN 476
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2020
ICS 23.040.05; 93.030 Will supersede EN 476:2011
English Version
General requirements for components used in drains and
sewers

Exigences générales pour les composants utilisés pour Allgemeine Anforderungen an Bauteile für

les branchements et les collecteurs d'assainissement Abwasserleitungen und -kanäle

This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee

CEN/TC 165.

If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations

which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other

language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC

Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.

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.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without

notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 476:2020 E

worldwide for CEN national Members.
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Contents Page

European foreword ....................................................................................................................................................... 4

1 Scope .................................................................................................................................................................... 5

2 Normative references .................................................................................................................................... 5

3 Terms and definitions ................................................................................................................................... 6

4 Symbols and abbreviations ...................................................................................................................... 12

5 Dimensional requirements....................................................................................................................... 13

5.1 General ............................................................................................................................................................. 13

5.2 Dimensions of pipes and fittings ............................................................................................................ 13

5.2.1 Nominal sizes ................................................................................................................................................. 13

5.2.2 Internal diameters and tolerances ........................................................................................................ 13

5.2.3 Geometrical characteristics of pipes ..................................................................................................... 13

5.2.4 Geometrical characteristics of fittings ................................................................................................. 14

5.3 Dimensions of manholes and inspection chambers ........................................................................ 15

5.3.1 Manholes ......................................................................................................................................................... 15

5.3.2 Inspection chambers ................................................................................................................................... 16

5.3.3 Geometrical characteristics of manholes and inspection chambers ......................................... 16

5.4 Covers and frames ....................................................................................................................................... 16

5.5 Connection to the pipe work .................................................................................................................... 16

6 Performance requirements ...................................................................................................................... 17

6.1 General ............................................................................................................................................................. 17

6.2 Mechanical performance of pipes and fittings .................................................................................. 17

6.2.1 Mechanical strength of pipes and fittings in the cross section .................................................... 17

6.2.2 Longitudinal bending moment resistance .......................................................................................... 18

6.3 Mechanical performance of shafts of manholes and inspection chambers ............................ 18

6.3.1 General ............................................................................................................................................................. 18

6.3.2 Circular sections ........................................................................................................................................... 18

6.3.3 Other shapes .................................................................................................................................................. 18

6.3.4 Tapers, reducing and cover slabs ........................................................................................................... 18

6.4 Tightness ......................................................................................................................................................... 19

6.4.1 Test pressure ................................................................................................................................................. 19

6.4.2 Sealings for joints ......................................................................................................................................... 20

6.4.3 Joint deflection .............................................................................................................................................. 20

6.4.4 Joint shear load ............................................................................................................................................. 21

6.4.5 Restrained joints .......................................................................................................................................... 21

6.5 Continuity of invert ..................................................................................................................................... 21

6.6 Temperature .................................................................................................................................................. 21

6.7 Dimensional stability .................................................................................................................................. 22

6.8 Smoothness of bore ..................................................................................................................................... 22

6.9 Appearance ..................................................................................................................................................... 22

6.10 Chemical and corrosion resistance ........................................................................................................ 22

6.11 Abrasion resistance ..................................................................................................................................... 22

6.12 Coatings and linings .................................................................................................................................... 22

6.13 Durability ........................................................................................................................................................ 22

6.14 Resistance against cleaning operations ............................................................................................... 23

6.15 Handling .......................................................................................................................................................... 23

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6.16 Reaction to fire .............................................................................................................................................. 23

7 Test methods .................................................................................................................................................. 23

7.1 Measurement of dimensions .................................................................................................................... 23

7.1.1 Mean internal diameter of pipes ............................................................................................................. 23

7.1.2 Mean external diameter of pipes ............................................................................................................ 23

7.1.3 Spigots and sockets ...................................................................................................................................... 23

7.1.4 Wall thickness of pipes ............................................................................................................................... 23

7.1.5 Deviation from straightness of pipes .................................................................................................... 23

7.1.6 Deviation from squareness of the ends of the pipes ........................................................................ 24

7.2 Load bearing capacity tests ....................................................................................................................... 24

7.2.1 Load bearing capacity tests for pipes .................................................................................................... 24

7.2.2 Load bearing capacity tests for sections of manholes and shafts................................................ 25

7.3 Longitudinal bending moment resistance test for pipes ............................................................... 25

7.4 Tightness tests ............................................................................................................................................... 25

7.4.1 Tightness test of pipes, fittings, manholes and inspection chambers ....................................... 25

7.4.2 Tightness test of joints ................................................................................................................................ 27

7.4.3 Test methods for discharge components for use inside buildings ............................................. 28

8 Marking, labelling and packaging ........................................................................................................... 28

Annex A (informative) Dimensions of pipes and fittings (nominal sizes) ............................................ 29

A.1 Preferred nominal sizes ............................................................................................................................. 29

Bibliography ................................................................................................................................................................. 30

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European foreword

This document (prEN 476:2020) has been prepared by Technical Committee CEN/TC 165 “Waste water

engineering”, the secretariat of which is held by DIN.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 476:2011.

The specifications of this document are based on the requirements for wastewater systems specified in

EN 752 and EN 12056. Significant technical differences between this edition and EN 476:2011 are as

follows:

a) the Scope is clarified in the way that this document contains requirements for product standards;

b) Table 1 (Preferred nominal sizes DN/ID) and Table 2 (Preferred nominal sizes DN/OD), paragraph

5.2.1, are moved to the new Annex A;

c) the paragraphs under subclause 5.3, Dimensions of manholes and inspection chambers, are

completely rewritten, with minimum internal dimension for different sections (always in

compliance with the national regulations in force at the place of installation);
d) for reaction to fire, a new subclause 6.15 is added.

This document provides a framework for the development of product standards to be used in drain and

sewer systems outside buildings. In Figure 1 the position of this document related to other standards on

this subject is given.

This document describes the general requirements to be taken into account in product standards.

Figure 1 — Pyramid diagram
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oSIST prEN 476:2020
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1 Scope

This document specifies general requirements to be respected in product standards for components

such as pipes, fittings, inspection chambers and manholes with their respective joints intended for use

in drains and sewers inside and outside buildings which operate as gravity systems allowing for a

maximum pressure of 40 kPa.

It also specifies general requirements for components used in hydraulically and pneumatically

pressurized discharge pipes, drains and sewers.

NOTE 1 Where the term “inside buildings” is used in the context of components fixed inside buildings, it also

includes discharge pipes and fittings fixed on external surfaces of buildings

NOTE 2 This document is not a product standard and therefore not intended for the direct evaluation of

products.

This document covers components to be used in conveying in a satisfactory manner:

— domestic wastewater;
— rainwater and surface water; and

— other waste waters acceptable for discharge into the system (e.g. industrial wastewater).

This document applies to components of circular and other cross sections.

This document applies equally to components which are factory-made and to those constructed on site,

where applicable.

NOTE 3 This document does not apply to components used for trenchless construction according to EN 14457

and for components used for renovation of drains and sewers according to EN 13380.

This document does not supersede the functional requirements of a complete system as defined in

EN 752.
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.

EN 124 (all parts), Gully tops and manhole tops for vehicular and pedestrian areas

EN 681-1, Elastomeric seals - Materials requirements for pipe joint seals used in water and drainage

applications - Part 1: Vulcanized rubber

EN 681-2, Elastomeric seals - Material requirements for pipe joint seals used in water and drainage

applications - Part 2: Thermoplastic elastomers

EN 681-3, Elastomeric seals - Material requirements for pipe joint seals used in water and drainage

applications - Part 3: Cellular materials of vulcanized rubber

EN 681-4, Elastomeric seals - Material requirements for pipe joint seals used in water and drainage

applications - Part 4: Cast polyurethane sealing elements

EN 682, Elastomeric seals - Materials requirements for seals used in pipes and fittings carrying gas and

hydrocarbon fluids
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EN 13501-1, Fire classification of construction products and building elements - Part 1: Classification

using data from reaction to fire tests

EN 13823, Reaction to fire tests for building products - Building products excluding floorings exposed to

the thermal attack by a single burning item

EN 16000, Plastics piping systems - Systems within the building structure - Mounting and fixing of

components in the test apparatus to thermal attack by a single burning item

EN ISO 11925-2, Reaction to fire tests - Ignitability of products subjected to direct impingement of flame -

Part 2: Single-flame source test (ISO 11925-2)

ISO 48-2, Rubber, vulcanized or thermoplastic - Determination of hardness - Part 2: Hardness between 10

IRHD and 100 IRHD
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https://www.iso.org/obp/ui
— IEC Electropedia: available at http://www.electropedia.org/
3.1
adjustable fitting

fitting which is designed to permit specific angular deflection at the time of installation (for pressurized

and vacuum systems)
3.2
adjustable joint

joint which permits significant angular deflection at the time of installation but not thereafter

3.3
crushing strength
load per unit length a rigid pipe is required to withstand in kN/m
3.4
external diameter

mean external dimension of the pipe barrel at any cross section where for pipes with external profiles

on the barrels, the external diameter is the maximum diameter when viewed in cross section

3.5
flexible joint
joint which permits angular deflection
3.6
flexible pipe

pipe, the load carrying capacity of which is limited by diametral deformation under load to the ultimate

design criteria without breaking or overstressing
Note 1 to entry: Materials such as PVC, PP, PE, etc.
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3.7
hydraulically pressurised system

system where flow is caused by hydraulic pressure and where the pipe normally operates full

3.8
inspection chamber

chamber with a removable cover constructed on a drain or sewer that permits the introduction of

cleaning and inspection equipment from surface level, but does not provide access for personnel

[SOURCE: EN 16323:2014, 2.2.4.13]
Note 1 to entry: Examples are given in Figure 4 and 5.
3.9
internal diameter
mean internal dimension of the pipe barrel at any cross section
3.10
invert

lowest point of the internal surface of the barrel of a pipe or channel at any cross section

3.11
joint

connection between the adjacent ends of two components including the means of sealing

3.12
manhole

chamber with a removable cover constructed on a drain or sewer to permit entry by personnel

[SOURCE: EN 16323:2014, 2.2.4.15]
Note 1 to entry: Examples are given in Figure 2 and 3.
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Key
1 adjusting unit
2 base unit
3 cover slab
4 chamber unit
5 reducing slab
6 shaft unit/riser
7 taper/cone
NOTE 1 Joint details have been omitted for clarity.

NOTE 2 Precast base slabs of structures can be integral with the base unit or a separate slab incorporating

construction joints.
Figure 2 — Description of manhole components
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Key
a cover 1 inlet
b near surface component 2 outlet
c telescopic adaptor 3 invert
d cone 4 inner diameter
e riser 5 benching
f base 6 channel
g connection
Figure 3 — Schematic representation of plastic manholes
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Key
1 adjusting unit
2 cover slab
3 shaft unit
4 base unit
NOTE Joint details have been omitted for clarity
Figure 4 — Description of inspection chamber components
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Key
a cover 1 inlet
b near surface component 2 outlet
c telescopic adaptor 3 invert
e riser 4 inner diameter
f base 5 benching
g connection 6 channel
Figure 5 — Schematic representation of plastic inspection chambers
3.13
nominal size

numerical designation of size of component, which is a convenient integer approximately equal to a

manufacturing dimension in millimetres and can apply to either the internal diameter (DN/ID) or the

external diameter (DN/OD)

Note 1 to entry: DN/OD pipes with solid or hollow spiral or annular profiled external surface and outside

smooth spigot jointing dimensions, and with larger external diameter than the spigot may be designated by the

spigot dimension.
3.14
pipe barrel

cylindrical part of the pipe with a uniform longitudinal profile excluding socket and spigot

3.15
pneumatically pressurized system

system where flow is caused by pneumatic pressure which can be applied either as compressed air

upstream or partial vacuum downstream and where the pipe normally operates full
3.16
restrained joint
joint in which a means is provided to prevent separation
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3.17
rigid joint
joint that does not permit angular deflection
3.18
rigid pipe

pipe, the load carrying capacity of which is limited by breaking or overstressing, without significant

deformation of its cross section
Note 1 to entry: Materials such as concrete, clay, etc.
3.19
ring stiffness

resistance of a pipe to diametral deflection in response to external loading applied along one diametric

plane given as follows:
EI⋅
3.20
test load

specified load which a component withstands where the related requirements of the product standard

are met
3.21
ultimate load

load which causes failure of a component (under test) which shall be as specified in product standards

4 Symbols and abbreviations
DN/ID nominal size related to the internal diameter
DN/OD nominal size related to the external diameter
PFA allowable operating pressure
PMA allowable maximum operating pressure
PEA allowable site test pressure
D diameter of the neutral axis of the pipe wall, in metres

E modulus of elasticity in flexure in the circumferential direction in kilonewtons per square

metre

I second moment of area of the pipe wall in the longitudinal direction, per unit length, in metres

to the fourth power per metre
S the ring stiffness of the pipe in kilonewtons per square metre
r radius for bends
α angle of bends
β angle of branches
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5 Dimensional requirements
5.1 General

The basic specifications as defined in the following clauses shall be respected in the product standards.

5.2 Dimensions of pipes and fittings
5.2.1 Nominal sizes

For circular products nominal sizes DN shall be given in product standards as DN/ID or DN/OD.

Table A.1 and A.2 contain sizes of preferred nominal sizes DN/ID and preferred nominal sizes DN/OD.

For non-circular products the relevant cross sections dimensions shall be specified in product

standards.
5.2.2 Internal diameters and tolerances
Product standards shall specify for circular products:
— internal diameters and tolerances; or
— external diameters, wall thicknesses and tolerances; or
— minimum internal diameter.
Maximum tolerances on the internal diameter are listed in Table 1.
Table 1 — Maximum tolerances on internal diameters
Nominal size Gravity, hydraulically and pneumatically pressurized
systems
Tolerances on mean Tolerances on individual
internal diameter internal diameter
mm mm
DN ≤ 100 ±0,05 × DN ±0,1 × DN
100 < DN ≤ 250 ±5 ±10
250 < DN ≤ 600 ±0,02 × DN ±0,04 × DN
DN > 600 ±15 ±30

For non-circular products the internal dimensions and tolerances shall be specified in product

standards.
5.2.3 Geometrical characteristics of pipes
Pipe straightness, including the tolerances, shall be specified (see 7.1.5).

When pipes are delivered in coils the minimum radius of the coils shall be specified instead of

straightness.

The angle between the planes of the end faces of the pipe and the relevant axis shall be 90° with a

tolerance such that the function of the pipe joint shall not be impaired (see 7.1.6).

Tolerances on pipe lengths shall be specified on pipe lengths, even if the lengths themselves are not

specified.
For pressurized systems, tolerances on the wall thickness shall be specified.
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5.2.4 Geometrical characteristics of fittings
5.2.4.1 General

Angles of fittings shall be specified in the product standards. Where applicable, tolerances on angles

shall be specified.
5.2.4.2 Bends

Angles α for bends (see Figure 6) shall be specified. Angles α should preferably be selected from 11°15′,

15°, 20° to 22°30′, 30°, 45°, 60° 67° to 70° and 87° to 90°. Other angles α may be specified.

Radii r for bends (e.g. swept and unswept) should be specified.
Key
α angle of bend
r radius of bend
Figure 6 — Illustrations of angle α and radius of bends r
5.2.4.3 Branches

Angles β for branches (see Figure 7) specified in product standards should preferably be selected from

45°, 60° to 70° or 87° to 90°.
Key
β angle of branches
Figure 7 — Illustrations of angle β of branches
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5.3 Dimensions of manholes and inspection chambers
5.3.1 Manholes

Manholes are for personnel access for maintenance works, cleaning and inspection.

The minimum dimensions of manholes deviate per country and local circumstances and should

therefore comply with the national regulations in force at the place of installation.

In the absence of national regulations, the diameter of the clear opening of the manhole cover according

to EN 124 shall be ≥ 600 mm (see Figure 8) and typical minimum internal dimensions of manholes (see

Figure 8 a) and 8 b) shall be as follows:
— for circular sections the minimum internal diameter: 1 000 mm;
— for rectangular sections the minimum internal dimensions: 750 mm × 1 200 mm;
— for square sections the minimum internal dimensions: 1 000 mm × 1 000 mm;
— for elliptical sections the minimum internal dimensions: 900 mm × 1 100 mm.

National or local safety regulations or the relevant authority might specify larger minimum dimensions

and design details, e.g. for the access and personal entry measures.

For personnel access under exceptional circumstances, and where national regulations allow, manholes

may have smaller dimensions according to Figure 8 c) with the following typical minimum internal

dimension:
— for circular sections the minimum internal diameter shall be 800 mm;

— for rectangular sections the minimum internal dimensions shall be 750 mm × 1 000 mm;

— for square sections the minimum internal dimensions shall be 800 mm × 800 mm;

— for elliptical sections the minimum internal dimensions shall be 800 mm × 1 000 mm.

Manholes for personnel access under exceptional circumstances should not be seen as an invitation to

accept dangerous situations.
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Dimensions in millimetres
a) b) c)
Key

a The 450 mm shaft depth (including the straight part of the taper/cone, if applicable) is recommended to

allow the first step or ladder rung to be in an accessible position. For septic tanks or separators, this

dimension can be increased up to 600 mm.
Figure 8 — Typical cases of manholes
5.3.2 Inspection chambers

Inspection chambers having DN/ID's less than 800 mm permit the introduction of cleaning, inspection

and test equipment, but do not provide access for personnel.
5.3.3 Geometrical characteristics of manholes and inspection chambers
Product standard
...