Fixed firefighting systems - Automatic sprinkler systems - Guidance for earthquake bracing

This document specifies requirements for earthquake protection of automatic sprinkler systems in accordance with EN 12845 . This document applies only to locations in earthquake zones in accordance to EN 1998-1:2004, 3.2.11) 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 Brandbekämpfungsanlage - Automatische Sprinkleranlagen - Leitfaden für Erdbebensicherungen

Dieses Dokument legt Anforderungen an die Erdbebensicherung von automatischen Sprinkleranlagen nach EN 12845 fest. Dieses Dokument gilt nur für Orte in Erdbebenzonen nach EN 1998 1:2004, 3.2.1 , und für Gebiete mit Spitzenwerten der Bodenbeschleunigung von mehr als 9 % der Erdbeschleunigung.
Dieses Dokument erfasst nicht alle gesetzlichen Anforderungen. In einigen Ländern gelten bestimmte nationale Vorschriften, die Vorrang vor diesem Dokument haben. Den Anwendern dieses Dokumentes wird empfohlen, sich bei den zuständigen Behörden ihres Landes über die Anwendbarkeit oder Nicht-Anwendbarkeit dieses Dokumentes zu informieren.

Installations fixes de lutte contre l'incendie - Systèmes d'extinction automatiques du type sprinkleur - Recommandation pour le contreventement sismique

Le présent document spécifie les exigences relatives à la protection sismique par des systèmes d’extinction automatiques de type sprinkleur conformément à l’EN 12845. Le présent document s’applique uniquement aux lieux situés en zones sismiques conformément à l’EN 1998-1:2004, 3.2.1 1) et pour une surface soumise à une accélération maximale du sol supérieure à 9 % de g.
Le présent document ne couvre pas toutes les exigences législatives. Dans certains pays, des réglementations nationales spécifiques s’appliquent et prévalent sur le présent document. Il est conseillé aux utilisateurs du présent document de s’informer sur l’applicabilité ou non du présent document auprès des autorités nationales responsables.

Vgrajene naprave za gašenje - Avtomatski sprinklerski sistemi - Navodila za zaščito pred potresi

General Information

Status
Published
Public Enquiry End Date
19-Nov-2020
Publication Date
22-Mar-2021
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
11-Mar-2021
Due Date
16-May-2021
Completion Date
23-Mar-2021

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SLOVENSKI STANDARD
SIST-TS CEN/TS 17551:2021
01-april-2021
Vgrajene naprave za gašenje - Avtomatski sprinklerski sistemi - Navodila za
zaščito pred potresi

Fixed firefighting systems - Automatic sprinkler systems - Guidance for earthquake

bracing
Ortsfeste Brandbekämpfungsanlage - Automatische Sprinkleranlagen - Leitfaden für
Erdbebensicherungen

Installations fixes de lutte contre l'incendie - Systèmes d'extinction automatiques du type

sprinkleur - Recommandation pour le contreventement sismique
Ta slovenski standard je istoveten z: CEN/TS 17551:2021
ICS:
13.220.10 Gašenje požara Fire-fighting
91.120.25 Zaščita pred potresi in Seismic and vibration
vibracijami protection
SIST-TS CEN/TS 17551:2021 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 17551:2021
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SIST-TS CEN/TS 17551:2021
CEN/TS 17551
TECHNICAL SPECIFICATION
SPÉCIFICATION TECHNIQUE
March 2021
TECHNISCHE SPEZIFIKATION
ICS 13.220.20
English Version
Fixed firefighting systems - Automatic sprinkler systems -
Guidance for earthquake bracing

Installations fixes de lutte contre l'incendie - Systèmes Ortsfeste Brandbekämpfungsanlage - Automatische

d'extinction automatiques du type sprinkleur - Sprinkleranlagen - Leitfaden für Erdbebensicherungen

Recommandation pour le contreventement sismique

This Technical Specification (CEN/TS) was approved by CEN on 4 January 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 17551:2021 E

worldwide for CEN national Members.
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CEN/TS 17551:2021 (E)
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 ........................................................................................................................................ 26

6.3 Seismic separation assemblies ............................................................................................................... 27

7 Clearance ........................................................................................................................................................ 29

7.1 Clearance around piping through walls or floors ............................................................................ 29

7.2 Clearance at sprinklers .............................................................................................................................. 29

8 Other provisions........................................................................................................................................... 29

8.1 Suspended ceilings ...................................................................................................................................... 29

8.2 Water supply ................................................................................................................................................. 29

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CEN/TS 17551:2021 (E)
European foreword

This document (CEN/TS 17551:2021) has been prepared by Technical Committee CEN/TC 191 “Fixed

firefighting systems”, the secretariat of which is held by BSI.

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.

According to the CEN-CENELEC Internal Regulations, the national standards organizations 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.
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SIST-TS CEN/TS 17551:2021
CEN/TS 17551:2021 (E)
Introduction

This document specifies requirements for earthquake protection of automatic sprinkler systems in

accordance with EN 12845 and fire hose piping systems. Requirements made herein are intended to

greatly improve the likelihood that the fire protection systems will remain in working condition during

earthquake and minimize or prevent any potential water damage from fixed firefighting systems leakage

due to an earthquake.
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CEN/TS 17551:2021 (E)
1 Scope

This document specifies requirements for earthquake protection of automatic sprinkler systems in

accordance with EN 12845. 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.
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 1998-1:2004, Eurocode 8: Design of structures for earthquake resistance - Part 1: General rules, seismic

actions and rules for buildings

EN 12845, Fixed firefighting systems - Automatic sprinkler systems - Design, installation and maintenance

3 Terms and definitions

For the purposes of this document, the terms and definitions given in EN 1998-1:2004 and EN 12845

apply.

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

— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
4 Design principles
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 the attached structure; 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 to minimize the potential for

pull-out, properly locate them and attach them to structural members only; and
As impacted by EN 1998-1:2004/AC:2009 and EN 1998-1:2004/A1:2013.
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CEN/TS 17551:2021 (E)

— 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 movement 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.

Two-way braces are either longitudinal or lateral. Longitudinal and lateral braces resist differential

movement perpendicular and parallel, respectively, to the axis of the pipe, and are used on feed mains,

cross mains, and system range pipes that are DN65 and larger in diameter.
Key
1 two-way brace longitudinal 3 four-way-brace
2 two-way brace lateral
Figure 1 — Sway bracing identification
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CEN/TS 17551:2021 (E)

Four-way sway bracing resists differential movement in all horizontal directions respectively, 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.

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.
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CEN/TS 17551:2021 (E)
Key
1 structural element (given as example- roof 5 0,6 m maximum
could be sloped or flat)
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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CEN/TS 17551:2021 (E)
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

In multi-storey buildings, a four-way brace shall be provided at each floor having a supply pipe.

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CEN/TS 17551:2021 (E)

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 will be necessary, 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

Provide lateral bracing 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, install additional lateral sway bracing 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

Provide lateral sway bracing 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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CEN/TS 17551:2021 (E)

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 m in diameter, lateral sway bracing is not needed 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

Provide longitudinal sway bracing 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.

Using braces on range pipes and riser nipples to brace distribution pipes is not allowed. In general,

bracing to smaller pipes shall not be used as the attachment points to brace larger pipes.

Sway bracing layout locations will usually need to coincide with the structural members to which the

sway braces will be attached.
5.2.2.6.4 Range pipes

Range pipes DN 50 and smaller 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. At the sprinkler terminal, install a restraint within 0,9 m for DN 25 pipe or

1,2 m for pipe DN 32 thru DN 50 additional restraints are required along the range pipe length at a

recommended spacing of 24 m.
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CEN/TS 17551:2021 (E)

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

the pipes. The (F ) for each sway bracing location are based on the weight of the water-filled piping

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.

Key
A See 5.2.3.4. D See 5.2.3.5 d).
B See 5.2.3.5 a). E See 5.2.3.6 a).
C See 5.2.3.5 b). F Can be omitted if equally distributed to brace 1 and
brace (see 5.2.3.6 a)).
Figure 4 — Zone of influence and related clauses
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CEN/TS 17551:2021 (E)

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
. The original formula (see
This method refers to the calculation procedure proposed in EN 1998-1:2004

EN 1998-1:2004, 4.24 ) 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

defined as follows:
SW× × g
( )
a aa
F = (1)
where

F horizontal seismic force, acting at the centre of mass of the water-filled piping in the

most unfavourable direction;
W weight of the water-filled piping;
S seismic coefficient;
g importance factor of the element;
q behaviour factor of the element.

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
— q = 2

In order to determine the Seismic Coefficient S , the following formula (see EN 1998-1:2004, 4.25 ) shall

be applied:
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SIST-TS CEN/TS 17551:2021
CEN/TS 17551:2021 (E)
Z
3×+1

(2)
S=α××S − 0,5
1+ 1−
T
1
where
α referred as peak ground acceleration (PGA) in [g] (see EN 1998-1:2004 );
S soil factor which varies depending on the kind of soil (see EN 1998-1:2004 );

Z height of the piping above the foundation level on the higher point of a rigid base;

H building height measured by the foundation or starting from the highest point of the rigid

base;
T fundamental period of vibration of the non-structural element;
T fundamental period of vibration of the building to the considered direction.

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

method based on the following formula:
F α××S 55,× W (3)
( )
where
α referred peak ground acceleration (PGA) in [g] (see EN 1998-1:2004 );
S soil factor assumed always equal to 1,15;
W weight of the water-filled piping within the zone of influence.

This formula draws always from 5.2.3.2, Formulas (1) and (2) of the Eurocode method, with the further

assumptions that the constant 5,5 derives from 5.2.3.2, Formula (1) to calculate S , assuming:

— Z = H;
— T = T .
a 1

The terms g and q have not been considered in order to get a higher F acting in favour of safety.

a a 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.
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CEN/TS 17551:2021 (E)
5.2.3.4 Calculation of design load for four-way sway bracing at risers

Calculate design loads to include the full length of the riser and the length of main distribution pipe 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

For the calculation of the design load for lateral two-way sway bracing the following shall be applied.

a) For main distribution pipes, calculate design loads to include the length of the main distribution pipe

being braced.

b) For distribution pipes, calculate design loads to include the length of distribution pipe being braced

plus all range pipe loads not distributed to range pipe longitudinal sway bracing.

c) For range pipes and portions of range pipes that are DN65 or larger and greater than 12 m in length,

the load distribution for the first lateral sway bracing location nearest the distribution pipe

connection, can either be equally distributed to the distribution pipe longitudinal bracing and the

first lateral sway bracing location (see 5.2.3.6 b)), or can be totally distributed to the first lateral sway

bracing location. Calculate the design loads for additional lateral sway bracing to include the length

of range pipe being braced.

d) For lateral sway braces that are located within 0,6 m of the end of a main distribution pipe or

distribution pipe connection to another perpendicular main of the same or smaller diameter, and

which will also be used as a longitudinal sway brace for that main, calculate the design load to include

the total lateral and longitudinal loads.
5.2.3.6 Calculation of design load for longitudinal two-way sway bracing

For the calculation of design load for longitudinal two-way sway bracing the following shall be applied:

a) for main distribution pipes, calculate design loads to include the length of main distribution pipe

being braced;

b) for distribution pipes, calculate design loads to include the length of distribution pipe being braced,

do not include loads from range pipes, except when a portion of range pipe lateral sway bracing is

being included as described in 5.2.3.5 c);

c) for range pipes that are DN65 or larger, calculate design loads to include the length of range pipe

being braced. The load for the piping between the distribution pipe and the first bracing location can

be equally distributed between that bracing location and the distribution pipe lateral sway bracing

as described in 5.2.3.5 b).

NOTE In certain cases, four-way braces can be used on distribution pipes or at main distribution

pipe/distribution pipe intersections to satisfy both longitudinal and latera
...

SLOVENSKI STANDARD
kSIST-TS FprCEN/TS 17551:2020
01-november-2020
Vgrajene naprave za gašenje - Avtomatski sprinklerski sistemi - Navodila za
zaščito pred potresi

Fixed firefighting systems - Automatic sprinkler systems - Guidance for earthquake

bracing
Ortsfeste Brandbekämpfungsanlage - Automatische Sprinkleranlagen - Leitfaden für
Erdbebensicherungen
Ta slovenski standard je istoveten z: FprCEN/TS 17551
ICS:
13.220.10 Gašenje požara Fire-fighting
91.120.25 Zaščita pred potresi in Seismic and vibration
vibracijami protection
kSIST-TS FprCEN/TS 17551:2020 en,fr,de

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

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kSIST-TS FprCEN/TS 17551:2020
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kSIST-TS FprCEN/TS 17551:2020
FINAL DRAFT
TECHNICAL SPECIFICATION
FprCEN/TS 17551
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
September 2020
ICS 13.220.20
English Version
Fixed firefighting systems - Automatic sprinkler systems -
Guidance for earthquake bracing
Ortsfeste Brandbekämpfungsanlage - Automatische
Sprinkleranlagen - Leitfaden für Erdbebensicherungen

This draft Technical Specification is submitted to CEN members for Vote. It has been drawn up by the Technical Committee

CEN/TC 191.

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 Technical Specification. It is distributed for review and comments. It is subject to change

without notice and shall not be referred to as a Technical Specification.
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. FprCEN/TS 17551:2020 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 ........................................................................................................... 22

5.4 Type, attachment and locations of hangers ........................................................................................ 23

6 Flexibility ........................................................................................................................................................ 24

6.1 General............................................................................................................................................................. 24

6.2 Flexible Couplings ........................................................................................................................................ 25

6.3 Seismic separation assemblies ............................................................................................................... 26

7 Clearance ........................................................................................................................................................ 27

7.1 Clearance around piping through walls or floors ............................................................................ 27

7.2 Clearance at sprinklers .............................................................................................................................. 27

8 Other provisions........................................................................................................................................... 28

8.1 Suspended ceilings ...................................................................................................................................... 28

8.2 Water supply ................................................................................................................................................. 28

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European foreword

This document (FprCEN/TS 17551:2020) 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 Vote on TS.
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Introduction

This document specifies requirements for earthquake protection of automatic sprinkler systems in

accordance with EN 12845 and fire hose piping systems. Requirements made herein are intended to

greatly improve the likelihood that the fire protection systems will remain in working condition during

earthquake and minimize or prevent any potential water damage from fixed firefighting systems leakage

due to an earthquake.
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1 Scope

This document specifies requirements for earthquake protection of automatic sprinkler systems in

accordance with EN 12845. 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.
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 1998-1:2004 , Eurocode 8: Design of structures for earthquake resistance - Part 1: General rules,

seismic actions and rules for buildings

EN 12845, Fixed firefighting systems - Automatic sprinkler systems - Design, installation and maintenance

3 Terms and definitions

For the purposes of this document, the terms and definitions given in EN 1998-1:2004 and EN 12845

apply.

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

— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
4 Design principles
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 the attached structure; 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 to minimize the potential for

pull-out, properly locate them and attach them to structural members only; and
1) As impacted by EN 1998-1:2004/AC:2009 and EN 1998-1:2004/A1:2013.
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— 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 movement 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.

Two-way braces are either longitudinal or lateral. Longitudinal and lateral braces resist differential

movement perpendicular and parallel, respectively, to the axis of the pipe, and are used on feed mains,

cross mains, and system range pipes that are DN65 and larger in diameter.
Key
1 two-way brace longitudinal 3 four-way-brace
2 two-way brace lateral
Figure 1 — Sway bracing identification
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Four-way sway bracing resists differential movement in all horizontal directions respectively, 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.

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.
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Key
1 structural element (given as example- roof 5 0,6 m maximum
could be sloped or flat)
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

In multi-storey buildings, a four-way brace shall be provided at each floor having a supply pipe.

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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 will be necessary, 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

Provide lateral bracing 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, install additional lateral sway bracing 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

Provide lateral sway bracing 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 m in diameter, lateral sway bracing is not needed 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

Provide longitudinal sway bracing 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.

Using braces on range pipes and riser nipples to brace distribution pipes is not allowed. In general,

bracing to smaller pipes shall not be used as the attachment points to brace larger pipes.

Sway bracing layout locations will usually need to coincide with the structural members to which the

sway braces will be attached.
5.2.2.6.4 Range pipes

Range pipes DN 50 and smaller 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. At the sprinkler terminal, install a restraint within 0,9 m for DN 25 pipe or

1,2 m for pipe DN 32 thru DN 50 additional restraints are required along the range pipe length at a

recommended spacing of 24 m.
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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

the pipes. The (F ) for each sway bracing location are based on the weight of the water-filled piping

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.

Key
A See 5.2.3.4. D See 5.2.3.5 d).
B See 5.2.3.5 a). E See 5.2.3.6 a).
C See 5.2.3.5 b). F Can be omitted if equally distributed to brace 1 and
brace (see 5.2.3.6 a)).
Figure 4 — Zone of influence and related clauses
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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
. The original formula (see
This method refers to the calculation procedure proposed in EN 1998-1:2004

EN 1998-1:2004, 4.24 ) 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

defined as follows:
SW× × g
( )
a aa
F = (1)
where

F horizontal seismic force, acting at the centre of mass of the water-filled piping in the

most unfavourable direction;
W weight of the water-filled piping;
S seismic coefficient;
g importance factor of the element;
q behaviour factor of the element.

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
— q = 2

In order to determine the Seismic Coefficient S , the following formula (see EN 1998-1:2004, 4.25 ) shall

be applied:

3×+1

S=α××S − 0,5 (2)
1+1−
T
where
α referred as peak ground acceleration (PGA) in [g] (see EN 1998-1:2004 );
S soil factor which varies depending on the kind of soil (see EN 1998-1:2004 );

Z height of the piping above the foundation level on the higher point of a rigid base;

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H building height measured by the foundation or starting from the highest point of the rigid

base;
T fundamental period of vibration of the non-structural element;
T fundamental period of vibration of the building to the considered direction.

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

method based on the following formula:
F α××S 55,× W (3)
( )
where
α referred peak ground acceleration (PGA) in [g] (see EN 1998-1:2004 );
S soil factor assumed always equal to 1,15;
W weight of the water-filled piping within the zone of influence.

This formula draws always from 5.2.3.2, Formulas (1) and (2) of the Eurocode method, with the further

assumptions that the constant 5,5 derives from 5.2.3.2, Formula (1) to calculate S , assuming:

— Z = H;
— T = T .
a 1

The terms g and q have not been considered in order to get a higher F acting in favour of safety.

a a 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

Calculate design loads to include the full length of the riser and the length of main distribution pipe 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

For the calculation of the design load for lateral two-way sway bracing the following shall be applied.

a) For main distribution pipes, calculate design loads to include the length of the main distribution pipe

being braced.

b) For distribution pipes, calculate design loads to include the length of distribution pipe being braced

plus all range pipe loads not distributed to range pipe longitudinal sway bracing.

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c) For range pipes and portions of range pipes that are DN65 or larger and greater than 12 m in length,

the load distribution for the first lateral sway bracing location nearest the distribution pipe

connection, can either be equally distributed to the distribution pipe longitudinal bracing and the

first lateral sway bracing location (see 5.2.3.6 b)), or can be totally distributed to the first lateral sway

bracing location. Calculate the design loads for additional lateral sway bracing to include the length

of range pipe being braced.

d) For lateral sway braces that are located within 0,6 m of the end of a main distribution pipe or

distribution pipe connection to another perpendicular main of the same or smaller diameter, and

which will also be used as a longitudinal sway brace for that main, calculate the design load to include

the total lateral and longitudinal loads.
5.2.3.6 Calculation of design load for longitudinal two-way sway bracing

For the calculation of design load for longitudinal two-way sway bracing the following shall be applied:

a) for main distribution pipes, calculate design loads to include the length of main distribution pipe

being braced;

b) for distribution pipes, calculate design loads to include the length of distribution pipe being braced,

do not include loads from range pipes, except when a portion of range pipe lateral sway bracing is

being included as described in 5.2.3.5 c).

c) for range pipes that are DN65 or larger, calculate design loads to include the length of range pipe

being braced. The load for the piping between the distribution pipe and the first bracing location can

be equally distributed between that bracing location and the distribution pipe lateral sway bracing

as described in 5.2.3.5 b).

NOTE In certain cases, four-way braces can be used on distribution pipes or at main distribution

pipe/distribution pipe intersections to satisfy both longitudinal and lateral bracing requirements. In those cases,

the longitudinal portion will include only the main distribution pipe or distribution pipe loads, while the lateral

portion will consider both the distribution pipe and range pipe loads (unless range pipes are provided with sway

bracing).
5.2.4 Step 3, select the proper sway bracing shape, size and maximum length
5.2.4.1 General

Sway bracing consists of either sufficient diagonal element(s) (at an angle of at least 30° from the

vertical), or diagonal plus vertical elements to resist both horizontal seismic loads and the net vertical

force components.

For braces used to resist tension and compression, the shape, size and length of the braces shall ensure

that the slenderness ratio, l/r (length/least radius of gyration), does not exceed 200, in order to provide

adequate resistance to buckling. For braces used in tension only, the l/r limitation shall not apply. Braces

can be steel pipe, steel angle, steel rods, steel flats, or steel cable under special conditions. For hangers

consider
...

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