EN 12056-3 2000 Gravity drainage systems inside buildings - Part 3 Roof drainage, layout and calculation.pdf

Licensed Copy Tom Dragicevic Bechtel Ltd 23 April 2003 Uncontrolled Copy c BSI BRITISH STANDARD BS EN 12056 3 2000 The European Standard EN 12056 3 2000 has the status of a British Standard ICS 91 060 20 91 140 80 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Gravity drainage systems inside buildings Part 3 Roof drainage layout and calculation Licensed Copy Tom Dragicevic Bechtel Ltd 23 April 2003 Uncontrolled Copy c BSIThis British Standard having been prepared under the direction of the Sector Committee for Building and Civil Engineering was published under the authority of the Standards Committee and comes into effect on 15 September 2000 BSI 09 2000 ISBN 0 580 36486 0 BS EN 12056 3 2000 Amendments issued since publication Amd No Date Comments National foreword This British Standard is the official English language version of EN 12056 3 2000 It supersedes BS 6367 1983 which is withdrawn The UK participation in its preparation was entrusted by Technical Committee B 505 Wastewater engineering to Subcommittee B 505 21 Roof drainage and sanitary pipework which has the responsibility to aid enquirers to understand the text present to the responsible European committee any enquiries on the interpretation or proposals for change and keep the UK interests informed monitor related international and European developments and promulgate them in the UK A list of organizations represented on this subcommittee can be obtained on request to its secretary The national annexes are an informative element of this standard and contain information provided to support easier implementation of EN 12056 3 2000 in the United Kingdom within the framework envisaged by the scope of that standard They therefore constitute a revision of those parts of BS 6367 1983 that are not otherwise superseded by BS EN 12056 3 2000 However users are reminded that only the normative elements of the adopted European Standard set out the provisions to which it is necessary to conform in order to form part of a trade description when citing this British Standard by number or when compliance with it is claimed Cross references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled International Standards Correspondence Index or by using the Find facility of the BSI Standards Electronic Catalogue A British Standard does not purport to include all the necessary provisions of a contract Users of British Standards are responsible for their correct application Additional information It is recognized that Figure 2 Figure 3 Figure 4 and Figure 11 along with the logic diagrams contained in annex D are of poor quality This has been reported to CEN in a proposal to correct them in the Engish language version of EN 12056 3 2000 Until the standard is corrected which BSI is not authorized to do it is strongly recommended that these figures be used with care Textual errors The textual errors set out below were discovered when the English language version of EN 12056 3 2000 was adopted as the national standard They have been reported to CEN in a proposal to amend the text of the European Standard Note 1 to Figure 8 should refer to Table 8 rather than Table 7 Note 3 to Figure 8 should refer to Table 8 rather than Table 7 Compliance with a British Standard does not of itself confer immunity from legal obligations Summary of pages This document comprises a front cover an inside front cover the EN title page pages 2 to 83 and a back cover The BSI copyright notice displayed in this document indicates when the document was last issued Licensed Copy Tom Dragicevic Bechtel Ltd 23 April 2003 Uncontrolled Copy c BSIEUROPEAN STANDARD NORME EUROP ENNE EUROP ISCHE NORM EN 12056 3 June 2000 ICS 91 060 20 91 140 80 English version Gravity drainage systems inside buildings Part 3 Roof drainage layout and calculation R seaux d vacuation gravitaire l int rieur des b timents Partie 3 Syst me d vacuation des eaux pluviales conception et calculs Schwerkraftentw sserungsanlagen innerhalb von Geb uden Teil 3 Dachentw sserung Planung und Bemessung This European Standard was approved by CEN on 27 October 1999 CEN members are bound to comply with the CEN CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration Up to date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member This European Standard exists in three official versions English French German A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions CEN members are the national standards bodies of Austria Belgium Czech Republic Denmark Finland France Germany Greece Iceland Ireland Italy Luxembourg Netherlands Norway Portugal Spain Sweden Switzerland and United Kingdom EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROP EN DE NORMALISATION EUROP ISCHES KOMITEE F R NORMUNG Central Secretariat rue de Stassart 36 B 1050 Brussels 2000 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members Ref No EN 12056 3 2000 E Licensed Copy Tom Dragicevic Bechtel Ltd 23 April 2003 Uncontrolled Copy c BSIPage 2 EN 12056 3 2000 BSI 09 2000 Contents Page Foreword 3 1 Scope 4 2 Normative references 5 3 Definitions and symbols 6 3 1 Definitions 6 3 2 Symbols 7 4 Runoff calculations 8 4 1 Quantity of rainwater runoff 8 4 2 Rainfall intensity r 9 4 3 Effective roof area A 10 5 Hydraulic design 11 5 1 Eaves gutters 11 5 2 Valley and parapet gutters 14 5 3 Gutter outlets 19 5 4 Flat roof outlets 21 6 Rainwater pipes 26 6 1 Part filled non siphonic systems 26 6 2 Siphonic systems 27 6 3 Drains 28 6 4 Connection to sanitary pipework 28 7 Layout 29 7 1 General 29 7 2 Gutters 29 7 3 Outlets 29 7 4 Emergency outlets 29 7 5 Access 29 7 6 Pipework 29 7 7 Trace heating 30 7 8 Change of building use 30 ANNEX A NORMATIVE TESTING OF GUTTERS AND OUTLETS 31 A 1 Capacity of gutter and outlet in combination 31 A 2 Capacity of gutter 32 A 3 Capacity of gutter outlet 32 ANNEX B INFORMATIVE NATIONAL AND LOCAL REGULATIONS AND PRACTICE 33 ANNEX C INFORMATIVE CAPACITY OF DRAINS 38 ANNEX D INFORMATIVE LOGIC DIAGRAMS 39 Licensed Copy Tom Dragicevic Bechtel Ltd 23 April 2003 Uncontrolled Copy c BSIPage 3 EN 12056 3 2000 BSI 09 2000 Foreword This European Standard has been prepared by Technical Committee CEN TC 165 Waste water engineering the secretariat of which is held by DIN This European Standard shall be given the status of a national standard either by publication of an identical text or by endorsement at the latest by December 2000 and conflicting national standards shall be withdrawn at the latest by June 2001 This part is the third in a series relating to the functional requirements of gravity drainage systems inside buildings There will be five parts as follows Gravity drainage systems inside buildings Part 1 General and performance requirements Part 2 Sanitary pipework Layout and calculation Part 3 Roof drainage Layout and calculation Part 4 Waste water lifting plants Layout and calculation Part 5 Installation and testing instructions for operation maintenance and use According to the CEN CENELEC Internal Regulations the national standards organizations of the following countries are bound to implement this European Standard Austria Belgium Czech Republic Denmark Finland France Germany Greece Iceland Ireland Italy Luxembourg Netherlands Norway Portugal Spain Sweden Switzerland and the United Kingdom Licensed Copy Tom Dragicevic Bechtel Ltd 23 April 2003 Uncontrolled Copy c BSIPage 4 EN 12056 3 2000 BSI 09 2000 1 Scope This European Standard applies to wastewater drainage systems which operate under gravity It is applicable for drainage systems inside dwellings and commercial institutional and industrial buildings This third part of this European Standard describes a method of calculating the hydraulic adequacy of non siphonic roof drainage systems and gives performance requirements for siphonic roof drainage systems It also sets standards for the layout and installation of roof drainage insofar as they affect flow capacity This part of this European Standard applies to all roof drainage systems where the outlets are large enough not to limit the flow capacity of the gutter i e free discharge conditions It applies to all materials used for roof drainage systems Detailed information additional to that contained in this Standard may be obtained by referring to the technical documents listed in Annex B Licensed Copy Tom Dragicevic Bechtel Ltd 23 April 2003 Uncontrolled Copy c BSIPage 5 EN 12056 3 2000 BSI 09 2000 2 Normative references This European Standard incorporates by dated or undated reference provisions from other publications These normative references are cited at the appropriate places in the text and the publications are listed hereafter For dated references subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision For undated references the latest edition of the publication referred to applies EN 12056 1 Gravity drainage systems inside buildings Part 1 General and performance requirements EN 12056 2 Gravity drainage systems inside buildings Part 2 Sanitary pipework layout and calculation EN 12056 5 Gravity drainage systems inside buildings Part 5 Installation and testing instructions for operation maintenance and use Licensed Copy Tom Dragicevic Bechtel Ltd 23 April 2003 Uncontrolled Copy c BSIPage 6 EN 12056 3 2000 BSI 09 2000 3 Definitions and symbols 3 1 Definitions For the purposes of this European Standard the following definitions apply 3 1 1 gutter angle deviation in gutter direction 3 1 2 design water depth maximum depth of water under design rainfall conditions 3 1 3 drainage length length of gutter from a stop end to an outlet or half the distance between adjacent outlets in millimetres 3 1 4 eaves gutter gutter where any spillover will discharge outside the building 3 1 5 flat sole sole of the gutter which is horizontal in cross section for at least the width of the outlet 3 1 6 freeboard total depth of gutter minus the designed water depth 3 1 7 long gutter gutter whose drainage length is greater than 50 times its design water depth 3 1 8 roof drainage of buildings all pipework and fittings outside and inside fixed to or passing through the building structure including drains below the building to the point of connection to the buried drain adjacent to the building used to remove precipitation from a roof See Scope of EN 12056 1 3 1 9 short gutter gutter whose drainage length is not greater than 50 times its design water depth 3 1 10 siphonic drainage system drainage system in which the outlets and pipework enable the system to flow completely full under design conditions and make use of the total head available between the outlets and the discharge point 3 1 11 spillover level level at which water will overflow the gutter Licensed Copy Tom Dragicevic Bechtel Ltd 23 April 2003 Uncontrolled Copy c BSIPage 7 EN 12056 3 2000 BSI 09 2000 3 2 Symbols For the purposes of this European Standard the following symbols have been used Symbol Description Unit Text reference A effective roof area m 2 Table 3 A E full cross sectional area of gutter mm 2 5 1 2 A W cross sectional area of the gutter below the freeboard mm 2 5 2 3 A O plan area of a gutter outlet mm 2 Figure 8 B R width of roof from gutter to ridge m Figure 1 C runoff coefficient dimensionless 4 1 d i internal diameter of pipe mm Table 8 D effective diameter of a gutter outlet mm Figure 9 D O actual diameter of a gutter outlet mm Figure 9 f filling degree of rainwater pipe which is equal to the proportion of cross section of rainwater pipe filled with water dimensionless Table 8 F d depth factor dimensionless Figure 5 F h outlet head factor dimensionless Figure 10 F L capacity factor for long and sloping gutters dimensionless Table 6 F s shape factor dimensionless Figure 6 h head at outlet mm Table 7 H R height of roof from gutter to ridge m Figure 1 h d water depth in drain mm annex C i pipe or gutter gradient dimensionless annex C k b effective pipe roughness mm Table 8 k O outlet coefficient dimensionless Table 7 L drainage length of gutter i e length of gutter from a stop end to an outlet or half the distance between two adjacent outlets mm Table 6 L R length of roof to be drained m Figure 1 L S length of sump mm Figure 11 L K length of taper of a gutter outlet mm Figure 9 L W length of weir over which water can flow mm 5 3 5 and Figure 12 Q rate of flow of water l s 4 1 Q d drain capacity l s annex C Q L design capacity of short gutter laid level l s 5 1 2 Q N nominal capacity of gutter l s 5 1 2 Q O total flow to an outlet calculated on area drained multiplied by the rainfall intensity l s Table 7 Licensed Copy Tom Dragicevic Bechtel Ltd 23 April 2003 Uncontrolled Copy c BSIPage 8 EN 12056 3 2000 BSI 09 2000 Symbol Description Unit Text reference Q RWP capacity of a rainwater pipe l s Table 8 Q SE capacity of an equivalent square eaves gutter l s 5 1 4 and Figure 3 Q SV capacity of an equivalent square valley or parapet gutter l s 5 2 3 R is the radius of a gutter outlet mm Figure 9 r rainfall intensity l s m 2 4 2 S width of gutter at sole mm Figure 4 T width of gutter at designated water line mm Figure 4 T R distance from gutter to ridge measured along the roof m Figure 1 P wetted perimeter mm annex A v flow velocity m s annex C W design water depth mm Figure 4 Z total depth of gutter to spillover level including freeboard mm Figure 4 kinematic viscosity of water m 2 s annex C 4 Runoff calculations 4 1 Quantity of rainwater runoff The rate of flow of rainwater to be drained away from a roof under steady state conditions shall be calculated from equation 1 Q r A C 1 where Q is the rate of flow of water in litres per second l s r is the rainfall intensity in litres per second per square metre l s m A is the effective roof area in square metres m C is a runoff coefficient taken as 1 0 unless national and local regulations and practice state otherwise dimensionless Licensed Copy Tom Dragicevic Bechtel Ltd 23 April 2003 Uncontrolled Copy c BSIPage 9 EN 12056 3 2000 BSI 09 2000 4 2 Rainfall intensity r 4 2 1 Where there is adequate statistical rainfall data related to the frequency of recurrence of storms of specific intensity and duration the rainfall intensity r used in equation 1 shall be chosen with due regard to the nature and use of the building and appropriate to the degree of risk that can be accepted Where statistical rainfall data is used clause 4 2 2 shall not apply 4 2 2 Where stati