On-site non-potable water systems - Part 1: Systems for the use of rainwater

This European Standard specifies the design, sizing, installation, identification, commissioning and maintenance of rainwater harvesting systems for the use of rainwater on-site as a substitute for potable water. This standard also specifies the minimum requirements for these systems.
Excluded from the scope of this standard are:
-   the use as drinking water,
-   decentralized attenuation,
-   infiltration.
NOTE   Conformity with the standard does not exempt from compliance of the obligations arising from local or national regulations.

Vor-Ort Anlagen für Nicht-Trinkwasser - Teil 1: Anlagen für die Verwendung von Regenwasser

Diese Europäische Norm legt Planung, Bemessung, Einbau, Kennzeichnung, Inbetriebnahme und Wartung von Regenwassernutzungsanlagen zur Verwendung von Regenwasser vor Ort als Ersatz für Trinkwasser fest. Diese Norm legt auch die Mindestanforderungen an solche Systeme fest.
Vom Anwendungsbereich dieser Norm ausgenommen sind:
—   die Verwendung als Trinkwasser,
—   dezentrale Rückhaltung,
—   Infiltration.
ANMERKUNG   Konformität mit dieser Norm entbindet nicht von der Einhaltung der Auflagen, die sich aus örtlichen oder nationalen Vorschriften ergeben können.

Réseaux d’eau non potable sur site - Partie 1 : Systèmes pour l’utilisation de l’eau de pluie

La présente norme spécifie la conception, le dimensionnement, l’installation, l’identification, la mise en service et l’entretien des systèmes de récupération de l’eau de pluie pour son utilisation sur site comme un substitut à l’eau potable. La présente norme spécifie également les exigences minimales relatives à ces systèmes.
Sont exclues du domaine d’application de la présente norme :
   l’utilisation comme eau potable ;
   l’atténuation décentralisée ;
   l’infiltration.
NOTE   La conformité à la présente norme ne dispense pas de se conformer aux obligations découlant des réglementations nationales ou locales.

Sistemi za vodo, ki ni namenjena pitju, nameščeni na terenu - 1. del: Sistemi za uporabo deževnice

Ta evropski standard določa načrtovanje, ugotavljanje velikosti, namestitev, prepoznavanje, zagon in vzdrževanje sistemov za zbiranje deževnice za njeno uporabo na terenu kot nadomestek za pitno vodo. Standard prav tako določa minimalne zahteve za te sisteme.
Ta standard ne zajema:
– uporabe pitne vode,
– decentraliziranega zmanjševanja odtoka vode,
– infiltracije.
OPOMBA: Skladnost s standardom ne pomeni, da lahko uporabnik opusti ukrepe za izpolnitev zahtev, ki izhajajo iz lokalnih ali nacionalnih predpisov.

General Information

Status
Published
Public Enquiry End Date
29-Jan-2016
Publication Date
13-Feb-2018
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
02-Feb-2018
Due Date
09-Apr-2018
Completion Date
14-Feb-2018

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Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 16941-1:2018
01-marec-2018
6LVWHPL]DYRGRNLQLQDPHQMHQDSLWMXQDPHãþHQLQDWHUHQXGHO6LVWHPL]D
XSRUDERGHåHYQLFH
On-site non-potable water systems - Part 1: Systems for the use of rainwater
Vor-Ort Anlagen für Nicht-Trinkwasser - Teil 1: Anlagen für die Verwendung von
Regenwasser
Réseaux d’eau non potable sur site - Partie 1 : Systèmes pour l’utilisation de l’eau de
pluie
Ta slovenski standard je istoveten z: EN 16941-1:2018
ICS:
93.025 Zunanji sistemi za prevajanje External water conveyance
vode systems
SIST EN 16941-1:2018 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 16941-1:2018

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SIST EN 16941-1:2018


EN 16941-1
EUROPEAN STANDARD

NORME EUROPÉENNE

January 2018
EUROPÄISCHE NORM
ICS 93.025
English Version

On-site non-potable water systems - Part 1: Systems for
the use of rainwater
Réseaux d'eau non potable sur site - Partie 1 : Systèmes Vor-Ort-Anlagen für Nicht-Trinkwasser - Teil 1:
pour l'utilisation de l'eau de pluie Anlagen für die Verwendung von Regenwasser
This European Standard was approved by CEN on 28 August 2017.

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. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.

This European Standard exists 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 16941-1:2018 E
worldwide for CEN national Members.

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SIST EN 16941-1:2018
EN 16941-1:2018 (E)
Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Functional elements of rainwater harvesting systems . 8
5 Design . 8
5.1 Collection . 8
5.1.1 General . 8
5.1.2 Collection surfaces . 9
5.1.3 Collection piping system . 9
5.2 Treatment . 9
5.2.1 General . 9
5.2.2 Preliminary treatment . 10
5.2.3 Additional treatment . 10
5.3 Storage . 10
5.3.1 General . 10
5.3.2 Materials . 11
5.3.3 Dimensions . 11
5.3.4 Capacity. 11
5.3.5 Structural behaviour . 11
5.3.6 Watertightness . 11
5.3.7 Connections and internal pipe system . 11
5.3.8 Access . 12
5.3.9 Overflow . 12
5.4 Back-up water supply . 12
5.4.1 General . 12
5.4.2 Backflow protection device . 13
5.5 Pumping . 14
5.5.1 General . 14
5.5.2 Submerged pump . 15
5.5.3 Non-submerged pump . 15
5.5.4 Expansion vessel . 16
5.5.5 Pump control unit . 16
5.6 System control with monitoring . 16
5.7 Metering . 17
5.8 Distribution . 17
5.9 Risk assessment . 17
6 Sizing . 18
6.1 Storage device . 18
6.1.1 General . 18
6.1.2 Determination of the available volume of rainwater. 19
6.1.3 Determination of the non-potable water demand per day . 20
6.1.4 Calculation methods . 20
2

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SIST EN 16941-1:2018
EN 16941-1:2018 (E)
6.2 Back-up water supply . 20
7 Installation . 21
8 Differentiation and identification. 21
9 Commissioning . 22
10 Quality of non-potable water . 22
11 Maintenance . 23
Annex A (informative) Examples of calculation methods for storage capacity . 24
A.1 General . 24
A.2 Examples of calculation methods . 24
A.2.1 Basic approach with annual time step . 24
A.2.2 Detailed approach . 25
A.2.2.1 General . 25
A.2.2.2 Input data . 26
A.2.2.3 Simulation principle . 26
A.2.2.4 Application of results . 27
Annex B (informative) Examples of rainwater harvesting systems with different back-up
supply arrangements . 29
Annex C (informative) Example for a commissioning sheet and logbook . 32
C.1 Commissioning sheet . 32
C.2 Logbook . 33
Annex D (informative) Inspection and maintenance . 34
Bibliography . 35

3

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SIST EN 16941-1:2018
EN 16941-1:2018 (E)
European foreword
This document (EN 16941-1:2018) has been prepared by Technical Committee CEN/TC 165
“Wastewater engineering”, the secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by July 2018 and conflicting national standards shall be
withdrawn at the latest by July 2018.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent
rights.
EN 16941, On-site non-potable water systems consists of the following parts:
— Part 1: Systems for the use of rainwater
— Part 2: Systems for the use of greywater (in preparation)
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.



4

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SIST EN 16941-1:2018
EN 16941-1:2018 (E)
Introduction
Ecological and sustainable water management is a goal of rainwater management. Herein rainwater
harvesting and infiltration, as well as the decentralized detention of rainwater, are alternatives to the
customary drainage of rainwater. Rainwater harvesting also reduces the potable water demand and the
discharge of water.
In order to keep the natural cycle of water, excess water from the rainwater harvesting system can be
infiltrated or otherwise evacuated in line with national or regional requirements.
On-site collection and use of rainwater covers a variety of applications like toilet flushing, laundry,
irrigation, climate control of buildings, cleaning, etc. at private and rented properties, residential areas,
community developments, industrial sites, hotels, streets, parks, golf courses, theme parks, car parks,
stadia, etc.
A generic flow chart of rainwater use on-site is presented in Figure 1.

Figure 1 — Generic flow chart of rainwater use
5

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SIST EN 16941-1:2018
EN 16941-1:2018 (E)
1 Scope
This European Standard specifies the requirements and gives recommendations for the design, sizing,
installation, identification, commissioning and maintenance of rainwater harvesting systems for the use
of rainwater on-site as non-potable water. This European Standard also specifies the minimum
requirements for these systems.
Excluded from the scope of this European Standard are:
— the use as drinking water and for food preparation;
— the use for personal hygiene purposes;
— decentralized attenuation;
— infiltration.
NOTE Conformity with the standard does not exempt from compliance with the obligations arising from local
or national regulations.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
EN 476, General requirements for components used in drains and sewers
EN 805, Water supply - Requirements for systems and components outside buildings
EN 806-2, Specification for installations inside buildings conveying water for human consumption - Part 2:
Design
EN 806-3, Specifications for installations inside buildings conveying water for human consumption - Part
3: Pipe sizing - Simplified method
EN 809, Pumps and pump units for liquids - Common safety requirements
EN 1295-1, Structural design of buried pipelines under various conditions of loading - Part 1: General
requirements
EN 1610, Construction and testing of drains and sewers
EN 1717, Protection against pollution of potable water in water installations and general requirements of
devices to prevent pollution by backflow
EN 12050 (all parts), Wastewater lifting plants for buildings and sites
EN 12056-1, Gravity drainage systems inside buildings - Part 1: General and performance requirements
EN 12056-3, Gravity drainage systems inside buildings - Part 3: Roof drainage, layout and calculation
EN 12056-4, Gravity drainage systems inside buildings - Part 4: Wastewater lifting plants - Layout and
calculation
6

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SIST EN 16941-1:2018
EN 16941-1:2018 (E)
EN 12056-5, Gravity drainage systems inside buildings - Part 5: Installation and testing, instructions for
operation, maintenance and use
EN 12566-3, Small wastewater treatment systems for up to 50 PT - Part 3: Packaged and/or site
assembled domestic wastewater treatment plants
EN 13076, Devices to prevent pollution by backflow of potable water - Unrestricted air gap-Family A -
Type A
EN 13077, Devices to prevent pollution by backflow of potable water - Air gap with non-circular overflow
(unrestricted) - Family A - Type B
EN 13564 (all parts), Anti-flooding devices for buildings
EN 16323:2014, Glossary of wastewater engineering terms
EN 60335-2-41, Household and similar electrical appliances - Safety - Part 2-41: Particular requirements
for pumps (IEC 60335-2-41)
EN ISO 4064 (all parts), Water meters for cold potable water and hot water (ISO 4064)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 16323:2014 and the following
apply.
3.1
rainwater
water arising from atmospheric precipitation
[SOURCE: EN 16323:2014, 2.1.1.1, modified]
3.2
rainwater harvesting
collecting rainwater from surfaces in order to be used
3.3
rainwater harvesting system
system for collecting rainwater from surfaces in order to be used, which consists of collection,
treatment, storage and distribution elements
3.4
storage device
unit for the storage of harvested rainwater
3.5
cistern
fixed container for holding water at atmospheric pressure for use as part of the plumbing system
3.6
non-potable water
water which has been made available for use, except for drinking, food preparation and personal
hygiene
7

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SIST EN 16941-1:2018
EN 16941-1:2018 (E)
3.7
non-return valve
device that prevents backflow of water
[SOURCE: EN 16323:2014, 2.2.5.12, modified: "wastewater" was changed to "water"]
3.8
volume of useable water
maximum volume of water that can be extracted from a storage device in normal use which is usually
from the overflow to the lowest extraction point
4 Functional elements of rainwater harvesting systems
Any rainwater harvesting system is described through four main functional elements:
— collection;
— treatment;
— storage; and
— distribution.
Rainwater harvesting systems shall be designed, installed, marked, operated and maintained in such a
way that the required level of safety is ensured at any time and that the required servicing work can be
easily carried out.
Rainwater harvesting systems shall not cause flooding and therefore shall include potential bypasses
and/or properly dimensioned overflows.
5 Design
5.1 Collection
5.1.1 General
The purpose of collection is to harvest rainwater and transport it to a storage device.
The following factors should be taken into account, as these can affect the quality and/or quantity of the
collected water:
— the local rainfall pattern;
— the size of the collection surface;
— the surface’s materials and their drainage characteristics;
— sizing and material of piping systems;
— the levels of pollution of the collection surface;
— the risk of contaminating the system.
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SIST EN 16941-1:2018
EN 16941-1:2018 (E)
5.1.2 Collection surfaces
5.1.2.1 Qualitative aspects
The characteristics of the collection surface (e.g. roofs and paved areas) shall be taken into
consideration depending on the intended use of the rainwater. Pollutants from other sources, e.g. traffic,
industry and animals have to be taken into account.
Common roof materials, e.g. glazed tiles and slate, do not cause any negative effect on the quality of
harvested rainwater.
Other roof collection surfaces may have potential to negatively affect the quality of the water harvested
(see examples in Table 1).
Table 1 — Examples of potential effects of collection surface on the quality of harvested
rainwater
Collection surface Potential effect
Green roof colouration
Bitumen containing material colouration
Cement with fibres emission of fibres in the long term
Copper, lead or zinc roofs increased concentrations of heavy metals
Weathered rough surfaces wash out of solids
Where paved areas or roof areas allowing human amenity are used for collection possible pollutants
due to the use of these areas shall be taken into account.
5.1.2.2 Quantitative aspects
Collection surfaces made of different materials have different characteristics regarding the drainage of
rainwater. The volume of the harvested rainwater is influenced by the surface yield coefficient (e).
Unless otherwise specified, typical values are given for different materials in 6.1.2, Table 2.
NOTE The surface yield coefficient differs from the run-off coefficient as specified in EN 12056-3, where it is
used for the hydraulic design of pipes. The surface yield coefficient aims to determine the average yield.
5.1.3 Collection piping system
Collection piping systems should allow the rainwater to flow from the collection surface to the storage
device by gravity or siphonic action. Access for inspection, maintenance and cleaning has to be planned
and installed.
Collection pipework from the roof within the rainwater harvesting system should not discharge into
open gullies because additional contamination could occur.
The non-pressure pipes and fittings shall meet the general requirements according to EN 476 and the
relevant product standards. The dimensioning shall be done in accordance with EN 12056-1 and
EN 12056-3. Underground rainwater pipes shall be designed according to EN 1295-1 and installed
according to EN 1610.
5.2 Treatment
5.2.1 General
The main purpose of treatment is to ensure a specific water quality depending on the intended use.
Additional purposes are the protection of the system components and the reduction of maintenance.
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SIST EN 16941-1:2018
EN 16941-1:2018 (E)
Treatment may involve biological, chemical or physical processes or a combination of them. Treatment
shall be done upstream within and potentially downstream of the storage device.
Treatment covers several operations:
— removal of coarse particles upstream of the storage (see 5.2.2);
— retention of fine particles by sedimentation and flotation in the storage device (see 5.3);
— filtering downstream of the storage device, depending on the intended use.
Disinfection, deodorization and/or discoloration may be required additionally (see 5.2.3).
A rainwater harvesting system shall provide water suitable for flushing toilets, laundry and garden
watering in most residential, industrial and commercial situations without the necessity of additional
treatment (see 5.2.3) unless identified by risk assessment referred to in 5.9.
The treatment system shall:
— be water resistant and durable;
— be accessible for maintenance (see Clause 11);
— not affect the hydraulic operation of the overall drainage system;
— withstand the maximum stresses and loads exerted during its handling, installation, use and
maintenance; and
— have a hydraulic efficiency ratio of at least 90 %.
The flow section of the overflow of the treatment device shall be designed for the discharge of
maximum flow.
5.2.2 Preliminary treatment
Preliminary treatment (e. g. filters, separators) shall be designed and located upstream of the storage
device and may consist of more than one device. The type and dimensioning of preliminary treatment
shall be selected according to the nature and size of the collection surface.
The purpose of preliminary treatment is to prevent the inflow of most coarse solids and organic matter
into the storage device. The maximum particle size entering the storage device shall be equal or less
than 1 mm for in-house use. If solids are retained, they shall be removed regularly or during a manual
intervention.
5.2.3 Additional treatment
Additional treatment (e. g. filtration, disinfection) of the stored rainwater shall be included if the
intended use demands higher quality.
5.3 Storage
5.3.1 General
The rainwater harvesting system shall, at a minimum, include one storage device which may be
positioned either above or below ground.
The purpose of the storage device is:
— to conserve a suitable volume of rainwater for the intended use and the collection possibilities;
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SIST EN 16941-1:2018
EN 16941-1:2018 (E)
— to treat the incoming water (sedimentation, flotation); and
— to protect the quality of this water from risks of deterioration.
The storage device shall be protected against frost, extreme temperatures and direct sunlight, for
instance buried underground.
The structural behaviour shall be taken into account when positioning the storage device.
5.3.2 Materials
The materials used shall not have a negative effect on the quality of the stored water and the
environment of the installation.
The materials (e. g. concrete, steel, Poly (vinyl chloride) (PVC-U), Polyethylene (PE), Polypropylene
(PP), Glass Reinforced Polyester (GRP-UP)) used for prefabricated factory built storage devices shall
meet the conditions described in EN 12566-3.
The material shall be non-translucent and/or UV stable. Where translucent material is used, light shall
be excluded.
The materials constituting the submerged components shall be corrosion resistant.
5.3.3 Dimensions
When prefabricated components are used, the overall dimensions, access and connection dimensions
and tolerances shall be stated by the manufacturer. Individual storage devices may be connected to
each other.
5.3.4 Capacity
The nominal capacity is the maximum volume of water that can be retained within the storage device
3
and shall be stated by the manufacturer or designer within ±0,1 m .
The capacity can be determined by testing or calculation.
5.3.5 Structural behaviour
Storage devices shall withstand the maximum stresses and loads exerted during its handling,
installation, use and maintenance. This shall be assessed either by calculation or testing.
Above-ground storage devices shall withstand the action of hydrostatic pressure without generating
excessive deformation adversely affecting its function.
5.3.6 Watertightness
The storage device shall be watertight at the level of:
— the walls constituting it;
— the couplings ensuring the hydraulic connections; and
— the storage device wall penetrations used for the possible passage of electric cables.
5.3.7 Connections and internal pipe system
The nominal diameters of the inlet and outlet fittings of the storage device shall be stated by the
manufacturer.
The inlets, outlets and other connections of the storage device shall be equipped with fittings with
standardized dimensions (i.e. sockets, spigots) equipped with seals and enabling assembly using
standardized pipes.
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SIST EN 16941-1:2018
EN 16941-1:2018 (E)
The inflow pipe of the harvested rainwater is terminated below the minimum water level of the storage
device to prevent the disturbance of any material at surface level. A calming inlet (see Figure 4) shall be
installed to prevent re-suspension of the solids that may have accumulated
...

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