prEN 12845-3
(Main)Fixed firefighting systems - Automatic sprinkler systems - Part 3: Guidance for earthquake bracing
Fixed firefighting systems - Automatic sprinkler systems - Part 3: Guidance for earthquake bracing
This document specifies requirements for earthquake protection of automatic sprinkler systems in accordance with the EN 12845 series of standards. This document applies only to locations in earthquake zones in accordance to EN 1998-1:2004, 3.2.1 and for area subject to peak ground acceleration above 9 % of g. This document does not cover all legislative requirements. In certain countries specific national regulations apply and take precedence over this document. Users of this document are advised to inform themselves of the applicability or non-applicability for this document by their national responsible authorities
Ortsfeste Brandbekämpfungsanlagen - Automatische Sprinkleranlagen - Leitfaden für Erdbebensicherungen
Dieses Dokument legt Anforderungen an die Erdbebensicherung von automatischen Sprinkleranlagen nach NormenreiheEN12845 fest. Dieses Dokument gilt für Gebäude, bei denen die zuständigen nationalen Behör
den die Notwendigkeit einer besonderen Erdbebensicherheit angeben.
Die in diesem Dokument festgelegten Grundsätze können je nach den örtlichen Anforderungen auch auf andere wasserbasierte ortsfeste manuelle oder automatische Brandbekämpfungsanlagen angewendet werden.
Installations fixes de lutte contre l'incendie - Systèmes d'extinction automatiques du type sprinkleur - Partie 3: Recommandation pour le contreventement sismique
Le présent document spécifie les exigences relatives à la protection sismique par des systèmes d’extinction automatique de type sprinkleur conformément à la série de normes EN 12845. Le présent document s’applique aux bâtiments pour lesquels les autorités nationales responsables spécifient la nécessité qu’ils présentent une résistance particulière aux séismes.
Les principes définis dans le présent document pourraient être applicables à d’autres systèmes fixes d’extinction manuelle ou automatique à base d’eau, selon les exigences locales.
Vgrajene naprave za gašenje - Avtomatski sprinklerski sistemi - 3. del: Navodila za zaščito pred potresi
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
oSIST prEN 12845-3:2022
01-september-2022
Vgrajene naprave za gašenje - Avtomatski sprinklerski sistemi - 3. del: Navodila za
zaščito pred potresi
Fixed firefighting systems - Automatic sprinkler systems - Part 3: Guidance for
earthquake bracing
Ortsfeste Brandbekämpfungsanlagen - Automatische Sprinkleranlagen - Leitfaden für
Erdbebensicherungen
Installations fixes de lutte contre l'incendie - Systèmes d'extinction automatiques du type
sprinkleur - Partie 3: Recommandation pour le contreventement sismique
Ta slovenski standard je istoveten z: prEN 12845-3
ICS:
13.220.10 Gašenje požara Fire-fighting
91.120.25 Zaščita pred potresi in Seismic and vibration
vibracijami protection
oSIST prEN 12845-3:2022 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN 12845-3:2022
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oSIST prEN 12845-3:2022
DRAFT
EUROPEAN STANDARD
prEN 12845-3
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2022
ICS 13.220.20 Will supersede CEN/TS 17551:2021
English Version
Fixed firefighting systems - Automatic sprinkler systems -
Part 3: Guidance for earthquake bracing
Installations fixes de lutte contre l'incendie - Systèmes Ortsfeste Brandbekämpfungsanlagen - Automatische
d'extinction automatiques du type sprinkleur - Partie Sprinkleranlagen - Leitfaden für Erdbebensicherungen
3: Recommandation pour le contreventement sismique
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 191.
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
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 12845-3:2022 E
worldwide for CEN national Members.
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Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Design principles . 5
5 Sway bracing and sprinkler pipe support . 6
5.1 General. 6
5.2 Sway brace design. 7
5.3 Anchorage for in rack sprinklers . 23
5.4 Type, attachment and locations of hangers . 24
6 Flexibility . 25
6.1 General. 25
6.2 Flexible Couplings . 25
6.3 Seismic separation assemblies . 26
7 Clearance . 28
7.1 Clearance around piping through walls or floors . 28
7.2 Clearance at sprinklers . 28
8 Other provisions. 28
8.1 Suspended ceilings . 28
8.2 Water supply . 29
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European foreword
This document (prEN 12845-3:2022) has been prepared by Technical Committee CEN/TC 191 “Fixed
firefighting systems”, the secretariat of which is held by BSI.
This document is currently submitted to the CEN Enquiry.
This document will supersede CEN/TS 17551: 2021.
In comparison with the previous edition, the following technical modifications have been made:
• Scope of the document was adjusted;
• Figure 3 and 8 were updated.
This standard is included in a series of European standards:
CEN/TS 14816, Fixed firefighting systems - Water spray systems - Design, installation and maintenance;
EN 671 (all parts), Fixed firefighting systems - Hose systems;
EN 12094 (all parts), Fixed firefighting systems - Components for gas extinguishing systems;
EN 12101 (all parts), Smoke and heat control systems;
EN 12259 (all parts), Fixed firefighting systems - Components for sprinkler and water spray systems;
EN 12416 (all parts), Fixed firefighting systems - Powder systems;
EN 12845-1, Fixed firefighting systems - Automatic sprinkler systems – Part 1: Design, installation and
maintenance;
EN 12845-2, Fixed firefighting systems - Automatic sprinkler systems - Part 2- Design and installation of
ESFR and CMSA sprinkler systems;
EN 13565 (all parts), Fixed firefighting systems - Foam systems;
EN 14972 (all parts), Fixed firefighting systems - Water mist systems;
EN 17451, Fixed firefighting systems - Automatic sprinkler systems - Design, assembly, installation and
commissioning of pump sets.
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Introduction
This document specifies requirements for earthquake protection of automatic sprinkler systems (see
EN 12845 (series)) and might be applicable to other water based fixed manual or automatic fire fighting
systems, according to local requirements. Requirements made herein are intended to greatly improve the
likelihood that the fire protection systems will remain in working condition during and after an
earthquake and minimize or prevent any potential water damage from fixed firefighting systems leakage
due to an earthquake.
This document does not cover all legislative requirements. In certain countries, specific national
regulations apply and take precedence over this document. Users of this document are advised to inform
themselves of the applicability or non-applicability for this document by their national responsible
authorities.
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1 Scope
This document specifies requirements for earthquake protection of automatic sprinkler systems in
accordance with the EN 12845 series of standards. This document applies to buildings, where national
responsible authorities specify the need of special earthquake resistance.
The principles defined in this document might be applicable to other water based fixed manual or
automatic fire fighting systems, according to local requirements.
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.
1
EN 1998-1:2004, Eurocode 8: Design of structures for earthquake resistance - Part 1: General rules,
seismic actions and rules for buildings
EN 12845-1, Fixed firefighting systems - Automatic sprinkler systems – Part 1: Design, installation and
maintenance
EN 12845-2, Fixed firefighting systems - Automatic sprinkler systems - Part 2- Design and installation of
ESFR and CMSA sprinkler systems
3 Terms and definitions
1
For the purposes of this document, the terms and definitions given in EN 1998-1:2004 , EN 12845, and
the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at https://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
3.1
zone of influence
portion of the piping system reinforced by a single sway brace which has to be calculated on both risers
and horizontal pipe runs
Note 1 to entry: Depending if related to a lateral or a longitudinal brace, it can include main distribution or
distribution pipes and range pipes or main distribution or distribution pipes only (see 5.2.3.4, 5.2.3.5, 5.2.3.6).
4 Design principles
Where required by local authorities, the earthquake protection measures of this document shall be
applied. The measures employed in this document shall be related to local peak ground acceleration.
NOTE 1 Attention is drawn to EN 1998-1:2004, 3.2.1. where a peak ground acceleration above 0,08 × g is
considered an earthquake risk.
NOTE 2 Some countries may have a national annex with guidance on updated peak ground acceleration values,
earthquake zones and building types for their specific country.
1
As impacted by EN 1998-1:2004/AC:2009 and EN 1998-1:2004/A1:2013.
5
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Requirements given in this document fall into the following seven principles:
— brace sprinkler piping and equipment to minimize uncontrolled differential movement between
these installations and structures they are attached to; and
— provide flexibility on piping systems and on equipment where differential movement between
portions of those piping systems or equipment is expected; and
— provide clearance between sprinkler piping and structural members, walls, floors or other objects so
that potential damage from impact is minimized; and
— provide anchorage or restraint to minimize potential sliding and/or overturning of equipment such
as the booster pump, jockey pump, tanks, controller, battery package and diesel tank; and
— use types of pipe hangers and sway bracing in accordance to EN 12845-1 and EN 12845-2 to
minimize the potential for pull-out, properly locate them and attach them to structural members
only; and
— use types of pipe joining methods in accordance to this document to minimize potential pipe breaks;
and
— provide fire protection system plans and calculations with proper verification of design and proper
verification that the completed installation is in accordance with this document and installed in
accordance with EN 12845.
5 Sway bracing and sprinkler pipe support
5.1 General
Sway bracing for sprinkler systems minimize differential movements between the piping system and the
structure to which it is attached.
Actual design of sway bracing is based on horizontal seismic load. Acceptable sway bracing type,
orientation and attachment methods (to both the sprinkler pipe and the structure) need to
simultaneously provide adequate resistance to both the horizontal seismic load and the net vertical uplift
force component resulting from the horizontal seismic load less any effective offset to that vertical force
component due to sprinkler piping dead weight.
For sprinkler piping within a building, there are two types sway bracing designs two-way and four-way.
Figure 1 shows two-way and four-way braces. They may be either longitudinal or lateral. Longitudinal
and lateral braces shall resist differential movement perpendicular and parallel, respectively, to the axis
of the pipe, and may be used on feed mains, cross mains, and system range pipes that are DN65 and larger
in diameter (see 5.2.2.6.2 and 5.2.2.6.3).
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Key
1 two-way brace longitudinal 3 four-way-brace
2 two-way brace lateral
Figure 1 — Sway bracing identification
Four-way sway bracing shall resist differential movement in all horizontal directions parallel to the axis
of the pipe, and is typically provided on the above-mentioned items and additionally on risers.
Where lateral and longitudinal sway bracing locations coincide, four-way bracing can be used to satisfy
design requirements for both.
For sway braces to protect the fire sprinkler against damage from earthquakes, their components shall
be shown to have a load capacity greater than the design earthquake load. This requires components to
be cyclical load testing to failure with allowed (design) load rating calculated using a minimum 1,5 safety
factor.
5.2 Sway brace design
5.2.1 Steps in designing sway brace
There are four general steps to properly design sway bracing.
— Step 1: Define sway bracing locations with respect to the sprinkler piping and to the structural
members to which the bracing will be attached.
— Step 2: Calculate the seismic design load requirements for each sway bracing location.
— Step 3: Select the proper sway bracing shape, angle of attachment, size and maximum length based
on the horizontal design load requirement.
— Step 4: Select the proper method to attach the sway bracing to the structure and to the piping.
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5.2.2 Step 1, define sway bracing locations
5.2.2.1 Risers
A four-way sway brace shall be provided on all sprinkler risers (whether single or manifolded type)
within 0,6 m of the top of the riser. Brace shall be attached to a structural element for risers located either
on the outside or on the inside of the building. The use of manifolded sway bracing at the top of multiple
adjacent risers requires careful design work and shall be avoided. If used, no more than two risers shall
be used in a manifolded arrangement, and bracing shall be designed to carry the total loads for both risers.
See Figure 2.
Key
1 structural element (given as example- roof could be sloped or flat) 5 0,6 m maximum
2 roof 6 elbow, flexible joint
3 4-way brace 7 flexible coupling
4 cladding (not structural element)
Figure 2 — Location of 4-ways sway bracing for riser
Intermediate four-way sway bracing shall be provided at an interval (vertical distance) not to exceed
12 m. Where flexible couplings are used, four-way sway bracing shall be provided within 0,6 m of every
other flexible coupling, with no more than two flexible couplings between sway brace locations. See
Figure 3.
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Key
1 4-way sway bracing at top of riser and flexible 5 rigid coupling
couplings within 0,6 m (as shown in
Figure 1)
2 flexible couplings 6 lateral sway bracing needed if run for horizontal pipe
exceeds 1,8 m, measured from centreline of 2
adjacent pipes
3 0,6 m maximum 7 manifold support
4 0,9 m maximum
Figure 3 — Location of 4-ways sway bracing for riser with manifold
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In multi-storey buildings, a four-way brace shall be provided at each floor having a supply pipe. A two-
way lateral sway brace shall be provided within 0,6 m of the end of any horizontal manifold piping longer
than 1,8 m, or when there is one or more flexible coupling(s) on either the horizontal manifold piping or
on the riser stub between the floor and the connection to the horizontal manifold piping.
5.2.2.2 Vertical distribution pipe or main distribution pipe piping
Four-way sway bracing shall be provided at both the top and bottom of the vertical pipe run of 1,8 m or
more. Each brace shall be located within 0,6 m of the respective piping turn. In addition, flexible couplings
shall be provided at the top and bottom. Intermediate four-way sway bracing shall be provided for risers
as recommended in 5.2.2.1.
For vertical pipe runs of less than 1,8 m without bracing, flexible couplings shall not be present within
the vertical pipe run (including the piping turns). If flexible couplings are provided at one or both turns
for vertical pipe runs of less than 1,8 m, then four-way bracing shall be provided within 0,6 m of each turn
equipped with flexible coupling(s).
5.2.2.3 Horizontal changes of direction
Distribution pipe or main distribution piping that has pipe runs of 1,8 m or more adjacent to the change
in direction shall be provided with both lateral and longitudinal sway bracing within 0,6 m the change of
direction. Straight pipe runs after the last change in direction shall be provided with sway bracing as
given in 5.2.2.4, 5.2.2.5 and 5.2.2.6. When the pipe connection at the change in direction is made using a
flexible coupling, then additional sway bracing as given in 5.2.2.5 shall be used, regardless of the length
of the pipe run adjacent to the change in direction.
5.2.2.4 Ends of main distribution pipes and distribution pipes
Lateral bracing shall be provided within 1,8 m of the end and provide longitudinal bracing within 12 m
of the end. When structural member locations for lateral sway bracing attachment are such that this 1,8 m
distance cannot be met, the distribution pipe or main distribution pipe shall be extended to allow proper
location of the lateral sway bracing. Seismic separation assemblies shall be considered as the end of
piping on both sides of the assembly.
5.2.2.5 Unnecessary flexible couplings
When more flexible couplings than recommended are installed on main distribution pipes and
distribution pipes, regardless of size, or on range pipes or portions of range pipes that are DN65 and
larger and greater than 6 m in length, additional lateral sway bracing shall be installed as follows:
— within 0,6 m of every other flexible coupling on straight pipe runs; and
— within 0,6 m of every flexible coupling installed at changes in horizontal pipe direction.
5.2.2.6 Straight pipe runs
5.2.2.6.1 General
After giving credit to any sway bracing installed as given in 5.2.2.1 to 5.2.2.5, sway bracing shall be
provided at a maximum spacing of 12 m for lateral sway bracing and 24 m for longitudinal sway bracing
per the following guidelines.
5.2.2.6.2 Lateral sway bracing
Lateral sway bracing shall be provided on all main distribution pipes and distribution pipes regardless of
size, and on all range pipes and portions of range pipes that are DN 65 and larger and greater than 1,8 m
in length. Space bracing at a maximum of 12 m, recognizing that for main distribution pipes and
distribution pipes, there shall be lateral bracing within 1,8 m of the end of the main(s), as given in 5.2.2.4.
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A four-way brace on a vertical pipe (e.g. at the top of a riser) can be counted as the initial lateral brace for
an attached horizontal pipe of the same or smaller diameter when the brace is located within 0,6 m of the
horizontal pipe.
The loads from range pipes or portions of range pipes DN 65 or larger and less than 1,8 m in length shall
be distributed to the longitudinal sway bracing on the distribution pipe as given in 5.2.3.
U-hangers, including wraparound types, shall not be used as lateral sway bracing for main distribution
pipes and distribution pipes. Wraparound U-hangers can be used as lateral sway bracing for range pipes
that require sway bracing if they meet the following criteria:
— have both legs bent out at least 30° from the vertical;
— have the proper diameter and length for the seismic loads involved;
— are properly attached to the building structure as given in 5.2.5; and
— there is no more than 13 mm of space between the top of the range pipes and the wraparound portion
of the U-hanger.
Only for range pipes less than DN 100 in diameter, lateral sway bracing can be omitted on pipes
individually supported by rods that meet the following criteria:
— all rods shall have a length of no more than 150 mm from the supporting member attachment to the
top of the range pipe;
— there shall be no more than 13 mm of space between the top of the range pipes and the bottom of the
support rod.
5.2.2.6.3 Longitudinal sway bracing
Longitudinal sway bracing shall be provided on all main distribution pipes and distribution pipes
regardless of size and on all range pipes and portions of range pipes that are DN 65 and larger, and greater
than 12 m in length. Space bracing at a maximum of 24 m, recognizing that for main distribution pipes
and distribution pipes, there shall be longitudinal bracing within 12 m of the end of the main(s), as given
in 5.2.2.4.
A four-way brace on a vertical pipe (e.g. at the top of a riser) can be counted as the initial longitudinal
brace for an attached horizontal pipe of the same or smaller diameter when the brace is located within
0,6 m of the horizontal pipe.
If a lateral brace is within 0,6 m of a pipe connection to another pipe which is perpendicular and of the
same or lesser pipe size, then the lateral brace can be used to also act as a longitudinal brace for the other
pipe, and the design load for the sway brace will need to include both the lateral and longitudinal loads
as given in 6.2.3.
Usage of braces on range pipes and riser nipples to brace distribution pipes shall not be used. In general,
bracing to smaller pipes shall not be used as the attachment points to brace larger pipes.
5.2.2.6.4 Range pipes
Range pipes DN 50 and smaller shall require restraint from excessive lateral movement and possible
damage. This can be done using sway braces or other alternate method to resist the movement. Restraints
do not require a load path design.
For tree or looped systems:
— at the sprinkler terminal, a restraint within 0,9 m for DN 25 pipe or 1,2 m for pipe DN 32 thru DN 50
shall be installed;
— additional restraints are required along the range pipe length at a recommended spacing of 24 m.
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For grid systems restraints are required along the range pipe length at a recommended spacing of 24 m.
5.2.3 Step 2, calculate seismic design load requirements for each sway bracing location
5.2.3.1 General
The design load requirements shall be calculated following two alternative methods referred respectively
to:
— Eurocode method given in 5.2.3.2, Formula (1); or
— the simplified method according to 5.2.3.3.
Both methods lead to the calculation of F , which is the horizontal force caused by the seismic actions on
a
the pipes. The (F ) for each sway bracing location are based on the weight of the water-filled piping
a
located within the zone of influence for that sway bracing location.
The zone of influence for a sway bracing location includes all piping to be included in the load distribution
calculation for that bracing location, based on the symmetrical layout of all the various bracing locations.
The Figure 4 provides examples of typical zone of influence and appropriate bracings as detailed from
5.2.3.4 to 5.2.3.6.
5.2.3.2 Eurocode method in accordance to EN 1998-1:2004
This method refers to the calculation procedure proposed in EN 1998-1:2004Error! Bookmark not
defined. The original formula (see EN 1998-1:2004, 4.24Error! Bookmark not defined.) applies to
non-structural elements as sprinkler pipes are. The following formula has been adapted to consider the
specificity of the sprinkler systems piping.
The effects of the seismic action shall be determined by calculating the horizontal force F which is
a
defined as follows:
SW× × g
( )
a aa
(1)
F =
a
q
a
where
F horizontal seismic force, acting at the centre of mass of the water-filled piping in the
a
most unfavourable direction;
W weight of the water-filled piping;
a
S seismic coefficient;
a
g importance factor of the element;
a
q behaviour factor of the element.
a
The importance factor of the element and the behaviour factor of the element can be considered as two
fixed constants with the following values:
— g = 1,5 (see EN 1998-1:2004, 4.3.5.3Error! Bookmark not defined.)
a
— q = 2 (see EN 1998-1:2004, Table 4.4Error! Bookmark not defined.)
a
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In order to determine the Seismic Coefficient S , the following formula (see EN 1998-1:2004, 4.25Error!
a
Bookmark not defined.) shall be applied:
Z
3×+1
H
(2)
S=α××S − 0,5
a
2
T
a
1+1−
T
1
where
α referred as peak ground acceleration (PGA) in [g] (see EN 1998-1:2004Error!
Bookmark not defined.);
S soil factor which varies depending on ground type (see EN 1998-1:2004, Table 3.1,
Table 3.2, Table 3.3Error! Bookmark not defined.);
Z height of the piping above the foundation level or the higher point of a rigid base in m;
H building height measured by the foundation or starting from the highest point of the rigid
base in m;
T Fundamental period of vibration of the non-structural element (piping system) in s;
a
T fundamental period of vibration of the building to the considered direction in s.
1
NOTE The PGA is typical of the geographical area taken into consideration. Each country can have specific value
for PGA enforced by local authority. In absence of local references, it is possible to refer to the European Seismic
Hazard Map available at www.share-eu.org.
5.2.3.3 Simplified method
As an alternate option to the Eurocode method, the F can be determined according to a simplified
a
method based on the following formula:
F α××S 55,× W (3)
( )
aa
where
α referred peak ground acceleration (PGA) in [g] (see EN 1998-1:2004Error!
Bookmark not defined.);
S soil factor assumed always equal to 1,15 (see EN 1998-1:2004, Table 3.1,
Table 3.2Error! Bookmark not defined.);
W weight of the water-filled piping within the zone of influence in kg.
a
This formula draws from Formulae (1) and (2) of the Eurocode method given in 5.2.3.2 with the further
assumptions that the constant 5,5 derives from 5.2.3.2, Formula (1) to calculate S , assuming:
a
— Z = H;
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— T = T .
a 1
For the terms g and q the ratio between g and q has been assumed always equal to 1 in order to get
a a a a
a higher F acting in favour of safety.
a
The simplified method will provide F values that are equivalent or more conservatives than the F value
a a
obtained by the full procedure as per 5.2.3.2.
5.2.3.4 Calculation of design load for four-way sway bracing at risers
Design loads shall be calculated to include the full length of the riser and the length of main distribution
piping within the zone of influence of the four-way riser brace. The four-way riser brace shall be designed
to handle both lateral and longitudinal design loads. Manifolded bracing design shall include the total
load for the risers being braced.
5.2.3.5 Calculation of design load for lateral two-way sway bracing
...
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