Design guideline for mechanically fastened roof waterproofing systems

This document gives guidance for the design of a roof waterproofing system mechanically fastened to the structural deck in relation to wind load resistance.
This document is intended to be used together with EN 16002 and the relevant clauses of EAD-030351-00-0402-2019.
This guideline does not include the seperate fastening requirements of the insulation boards, the securement to upstands, perimeter fastening, flashings or other roof details.

Richtlinie für die Konstruktion von mechanisch befestigten Dachabdichtungssystemen

Dieses Dokument beinhaltet eine Richtlinie für das Entwurfskonzept eines Dachsystems in Bezug auf die Widerstandsfähigkeit gegen Windlast, das mechanisch an einer Tragkonstruktion befestigt ist.
Dieses Dokument ist für die Anwendung zusammen mit EN 16002 und den zutreffenden Abschnitten der EAD 030351 00 0402-2019 vorgesehen.
Dieser Leitfaden enthält keine separaten Anforderungen an die Befestigung der Dämmplatten, Befestigung an Aufsetzkränzen, Perimeter-Befestigungen, Verwahrungsbleche oder anderer Einzelteile des Dachs.

Règles de conception des systèmes d’étanchéité de toiture fixés mécaniquement

Le présent document fournit des recommandations pour la conception d’un système d’étanchéité de toiture fixé mécaniquement à l’élément porteur en relation avec la résistance à la charge due au vent.
Le présent document est destiné à être utilisé conjointement avec l’EN 16002 et avec les articles pertinents du DEE-030351-00-0402-2019.
La présente ligne directrice n’inclut pas les exigences particulières de fixation des panneaux isolants, la tenue au niveau des relevés, la fixation périphérique, les solins ou autres détails de toiture.

Smernice za načrtovanje mehansko pritrjenih strešnih hidroizolacijskih sistemov

Ta dokument podaja smernice za načrtovanje strešnih hidroizolacijskih sistemov, mehansko pritrjenih na konstrukcijo, v zvezi z odpornostjo proti obremenitvi z vetrom.
Ta dokument je namenjen za uporabo skupaj s standardom EN 16002 in z ustreznimi členi standarda EAD-030351-00-0402-2019.
Te smernice ne vključujejo ločenih zahtev glede pritrditve izolacijskih plošč, pritrditve na podstavke, pritrditve na obodu, obrob ali drugih podrobnosti strehe.

General Information

Status
Published
Publication Date
07-Dec-2021
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
22-Nov-2021
Due Date
27-Jan-2022
Completion Date
08-Dec-2021

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SLOVENSKI STANDARD
SIST-TS CEN/TS 17659:2022
01-januar-2022
Smernice za načrtovanje mehansko pritrjenih strešnih hidroizolacijskih sistemov
Design guideline for mechanically fastened roof waterproofing systems
Richtlinie für die Konstruktion von mechanisch befestigten Dachabdichtungssystemen
Règles de conception des systèmes d’étanchéité de toiture fixés mécaniquement
Ta slovenski standard je istoveten z: CEN/TS 17659:2021
ICS:
91.060.20 Strehe Roofs
91.100.50 Veziva. Tesnilni materiali Binders. Sealing materials
SIST-TS CEN/TS 17659:2022 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TS CEN/TS 17659:2022

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SIST-TS CEN/TS 17659:2022


CEN/TS 17659
TECHNICAL SPECIFICATION

SPÉCIFICATION TECHNIQUE

November 2021
TECHNISCHE SPEZIFIKATION
ICS 91.100.50
English Version

Design guideline for mechanically fastened roof
waterproofing systems
Règles de conception des systèmes d'étanchéité de Richtlinie für die Konstruktion von mechanisch
toiture fixés mécaniquement befestigten Dachabdichtungssystemen
This Technical Specification (CEN/TS) was approved by CEN on 16 August 2021 for provisional application.

The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to
submit their comments, particularly on the question whether the CEN/TS can be converted into a European Standard.

CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS
available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in
parallel to the CEN/TS) until the final decision about the possible conversion of the CEN/TS into an EN is reached.

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.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 17659:2021 E
worldwide for CEN national Members.

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CEN/TS 17659:2021 (E)
Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Symbols and abbreviations . 6
5 Introduction to design concept . 7
5.1 Introduction . 7
5.2 Actions on structures - Eurocode 1 . 7
5.3 Wind load resistance of the roof . 7
5.4 Safety factors. 7
6 Wind load - Design value of the wind pressure . 8
) . 8
6.1 Wind pressure (w
tot
6.2 Wind load, Q . 8
wind;d
7 Admissible (design) load resistance of the waterproofing system . 9
7.1 General . 9
7.2 Method 1 - Full scale dynamic wind load system test . 9
7.3 Method 2 – Using data from fastener manufacturer's ETA - Weakest link in the
system concept . 10
7.4 Method 3 - On site field pull-out testing of the fastener - weakest link in the system
concept . 11
8 Fastener density and positioning of the fasteners . 12
8.1 Fastener density . 12
8.2 Positioning of the fasteners . 12
9 Material partial (safety) factors, γ . 14
M
9.1 Material partial factor - dynamic full-scale testing . 14
9.2 Material partial factor – pull-out value and field pull-out test . 14
9.3 Material partial factor – Pull-over value . 15
10 Interpolation and application rules . 15
10.1 General . 15
10.2 Flexible sheets . 16
11 Field pull-out test . 16
11.1 General . 16
11.2 Test equipment . 16
11.3 Test method . 17
11.4 Test procedure . 18
11.5 Calculation of the characteristic load per fastener . 18
Bibliography . 20

2

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CEN/TS 17659:2021 (E)
European foreword
This document (CEN/TS 17659:2021) has been prepared by Technical Committee CEN/TC 254 “Flexible
sheets for waterproofing”, the secretariat of which is held by NEN.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to announce this Technical Specification: 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 the United
Kingdom.
3

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CEN/TS 17659:2021 (E)
1 Scope
This document gives guidance for the design of a roof waterproofing system mechanically fastened to the
structural deck in relation to wind load resistance.
This document is intended to be used together with EN 16002 and the relevant clauses of EAD-030351-
00-0402-2019.
This guideline does not include the seperate fastening requirements of the insulation boards, the
securement to upstands, perimeter fastening, flashings or other roof details.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
1
EN 1990:2002, Eurocode — Basis of structural design
EN 1991-1-4, Eurocode 1: Actions on structures — Part 1-4: General actions — Wind actions
EN 16002:2018, Flexible sheets for waterproofing — Determination of the resistance to wind load of
mechanically fastened flexible sheets for roof waterproofing
EAD-030351-00-0402-2019, Systems of mechanically fastened flexible roof waterproofing sheets
EN 13707, Flexible sheets for waterproofing — Reinforced bitumen sheets for roof waterproofing —
Definitions and characteristics
EN 13956:2012, Flexible sheets for waterproofing — Plastic and rubber sheets for roof waterproofing —
Definitions and characteristics
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 13707 and EN 13956 and the
following apply.
3.1
fastener
object to fasten the fixing element to a structural deck
Note 1 to entry: Fastener can be e.g. a screw, nail, expanding anchor or rivet.
3.2
fastening system
assembly of the fastener and the fixing element intended to secure the waterproofing system to the
structural deck
Note 1 to entry: Fastening system can be e.g. a fastener with a:
- metal washer with or without a plastic sleeve,
- plastic washer with or without an integrated sleeve, or
- metal bar/continuous strips with or without a plastic sleeve.

1
As impacted by EN 1990:2002/A1:2005 and EN 1990:2002/A1:2005/AC:2010.
4

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Note 2 to entry: Whilst primarily intended to secure the waterproofing system against wind uplift forces, the
system may contribute to securing intermediate layers such as thermal insulation, air and vapour control layers
(AVCL), etc.
3.3
fixing element
component that secures the waterproofing system, in connection with the fastener, to the structural deck
Note 1 to entry: A fixing element is the fastening system without the fastener.
3.4
flexible sheet for waterproofing
factory made waterproofing sheet, which can be rolled up or folded for easy transport to the site
[Source: EN 13956:2012, 3.4, modified —"Roof" omitted in the term.]
3.5
pull-through failure
failure mode between the fixing element and the waterproofing system
Note 1 to entry: The failure mode can vary dependent of type of fixing element, type of flexible sheet for
waterproofing as well as the design of the waterproofing system.
3.6
pull-out failure
failure mode in which the fastener pulls out of the structural deck
3.7
pull-over failure
failure mode in which the fastener pulls through the fixing element
Note 1 to entry: This is called "washer pull-through test" in EAD −030351-00-0402-2019.
3.8
roof build-up
total of different layers which forms the roof from the structural deck to the waterproofing system
including the fastening system
3.9
structural deck
construction element, e.g. roofing panel or slab, which has to transfer both permanent and variable loads
to the other construction parts of the roof or building
3.10
waterproofing system
assembly of one or more layers of flexible sheets for waterproofing in its applied and jointed form, which
has certain performance characteristics, to be assessed as a whole
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4 Symbols and abbreviations
For the purposes of this document, the following symbols apply.
  Unit
c external pressure coefficient -
pe1
c internal pressure coefficient -
pi
k coefficient -
n
2
n -
minimal required number of fasteners per m
f
n number of samples within one roof area -
2
n -
minimum number of fasteners per m
min
2
Q design value of the wind pressure
kN/m
wind;d
2
q peak velocity pressure
kN/m
p
R
admissible (design) value of axial pull-out load of the fastener in the kN
d;field pull-out
specific structural deck on site
R admissible (design) pull-out value of the fastening system in a specific kN
d;pull-out
structural deck
R admissible (design) pull-over value of the fastening system kN
d;pull-over
R
characteristic value of axial pull-out load of the fastener in the specific kN
k;field pull-out
structural deck on site
R characteristic pull-out value in a specific structural deck kN
k;pull-out
R characteristic pull-over value kN
k;pull-over
s standard deviation -
∆W admissible (design) load for the resistance to wind uplift per fastening kN
adm
system
W admissible (design) load resistance of the waterproofing system per kN
adm;system
fastener
∆W characteristic load for the resistance to wind uplift kN
char
2
w external wind pressure
kN/m
e
2
w internal wind pressure
kN/m
i
2
w characteristic value of the wind pressure
kN/m
tot
x
mean value of all field pull-out tests kN
m
x test result of test i with i is 1 to n kN
n;i
γ partial (safety) factor for wind load -
Q
γ material partial factor -
M

6

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5 Introduction to design concept
5.1 Introduction
This technical specification intends to give guidance how to use EN 1991-1-4 in practice when designing
a roof with a mechanically fastened waterproofing system. This document is intented to be used together
with EN 16002 and EAD-030351-00-0402-2019.
5.2 Actions on structures - Eurocode 1
5.2.1 General
Eurocode 1 on actions on structures (abbreviated EN 1991 or, informally, EC 1) describes how to design
load-bearing structures. It includes characteristic values for various types of loads and densities for all
materials which are likely to be used in construction.
EN 1991-1-4 gives guidance on the determination of natural wind actions for the structural design of
building and civil engineering works for each of the loaded areas under consideration. This includes the
whole structure or parts of the structure or elements attached to the structure, e.g. components, roofing,
cladding units and their fixings.
5.2.2 National annex for EN 1991-1-4
EN 1991-1-4 gives alternative procedures, values and recommendations for classes with notes indicating
where national choice may be made. Therefore, the National standard of EN 1991-1-4 should have a
National Annex containing National Determined Parameters to be used for the design of buildings in the
relevant country.
EN 1991-1-4 is intended to be used in conjunction with EN 1990, the other parts of EN 1991 and EN 1992
series to EN 1999 series for the design of structures.
5.3 Wind load resistance of the roof
Mechanically fastened waterproofing systems are tested according to EN 16002:2018. Fastening systems
are tested according to EAD-030351-00-0402-2019. The evaluated result, as described in Clause 7, gives
the conditions for the roof resistance and design possibilities with regards to the calculated wind
pressure for the roof.
The evaluation of the test results identifies the weakest of the three failure modes:
— pull-through of fixing element;
— pull-out of the fastener;
— pull-over of the fixing element.
The weakest of these three gives the authoritative design value for the system, W .
adm;system
5.4 Safety factors
When designing a mechnichally attached flexible waterproofing system using the partial coefficient
method the total safety is considered using different safety factors for the actions and the materials. The
actions are considered by use of the probability and the durability whereas the components are
considered by the material characteristics.
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6 Wind load - Design value of the wind pressure
6.1 Wind pressure (w )
tot
2
EN 1991-1-4 defines the wind pressure per m for each zone on the roof (e.g. corner-, perimeter- and
field zone) from the formula:
w = w+=w q c − c (1)
( )
tot i e p pe1 pi
where
2
w
is the characteristic value of the wind pressure, in kN/m ;
tot
2
w
is the external wind pressure, in kN/m ;
e
2
w
is the internal wind pressure, in kN/m ;
i
2
q
is the peak velocity pressure according to EN 1991-1-4, in kN/m ;
p
c is the external pressure coefficient according to EN 1991-1-4;
pe1
c is the internal pressure coefficient according to EN 1991-1-4.
pi

The wind pressures are characteristic values. They are determined from the basic values of wind velocity
or the wind velocity pressure. In accordance with EN 1990 the basic values are representative values
having annual probabilities of exceedance of 0,02 which is equivalent to a mean return period of 50 years.
6.2 Wind load, Q
wind;d
For the calculation of the design value of the wind pressure, Q , the representative value of the wind
wind;d
pressure, w shall be multiplied by the partial (safety) factor for wind load, γ . The recommended value
tot Q
for γ is 1,5, but different values may be set by national annexes.
Q
Qw×γ (2)
wind;d tot Q
where
2
Q
is the design value of the wind pressure, in kN/m ;
wind;d
2
w
is the characteristic value of the wind pressure, according to Formula (1), in kN/m ;
tot
γ is the partial (safety) factor for wind load.
Q

NOTE For flexible waterproofing, several European countries are using reduction factors which could lead to
a different safety factor, based on consequence classes (EN 1990, CC) judged on the possible low risk of human
injury with installations of flexible waterproofing membranes.
8
=

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7 Admissible (design) load resistance of the waterproofing system
7.1 General
The characteristic value of the load resistance of the waterproofing system and fastening system should
be provided by the membrane or fastener supplier respectively, taking into consideration the following
failures:
— pull-through of the fastening system, determined with the full scale dynamic wind load test according
to EN 16002:2018,
— pull-
...

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