! "##!!$%$&'(&) "&$## $%& '!($( +,' *- $ + $.$ $ $ / /

! "##!!$%$&'(&) "&$##!"# $%& '!($(!)"#( *# +,' *- $ + $.$ $ $ / / /$"

*+,*&$##"* ')!"# $%& 3!)"#( *# '!($( +,' *- $ + $.$ $ $ / / /$" (! "*"-*( **"**-*-*-.-..*.! * - "! / "! ' ).""&$##! / " "!" # $!%&'(!%&'( )*(+,,#-% )*(+,,#-% 1 23#4$4&##555 6!78! 9" ::...!!!(# $(/(/ #8#8$$:*$($$ #$#$#$/$( $(# :: :* $( /* $ 3 $$#$ $/ $( $%$$ $( $/ 367425434.58)9

+!! 1 Introduction... 7 2 EGIG database... 9 2.1 Definition... 9 2.2 Objective... 9 2.3 Criteria... 9 2.4 Contents... 9 2.5 The use of EGIG Data... 1 3 Analyses and results... 12 3.1 Definitions... 12 3.2 Trends of the European gas transmission system... 12 3.2.1 Total length... 13 3.2.2 Exposure... 17 3.3 Failure frequencies analyses... 18 3.3.1 Number of incidents... 18 3.3.2 Primary failure frequencies... 2 3.3.3 Secondary failure frequencies... 25 3.3.3.1 Relation between external interference, size of leak and design parameter... 26 3.3.3.2 Relation between corrosion, size of leak and design parameter... 29 3.3.3.3 Relation between construction defect, size of leak and design parameter... 33 3.3.3.4 Relation between hot tap made by error, size of leak and design parameter... 34 3.3.3.5 Ground movement... 35 3.3.3.6 Other and unknown... 37 3.4 Other analysis... 38 3.4.1 Ageing... 38 3.4.2 Detection of incidents... 39 3.4.3 Ignition probability... 4 3.4.4 Injuries and fatalities... 4 4 Conclusions and facts... 41 5 Reference... 41 367425434.98)9

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

!( $$# $($* $ 88$ $( $!( $ 8$( #$:$( $$ $8$$($#* $#$8$($* ;8 $ 888$ :/( * /(/ $#* 88$ $ (*:#8*8 / ## ("!($$ %%8: $$/(#(//$* / #, $8$($* ##$#$ *$ $8$$($$ $(8$( *: 8$( $://$* 8$(:$* $8/( $* ##$ $8$$($(#( 8$(:$* $ 367425434.18)9

2 EGIG DATABASE 2.1 Definition!($* $* 8#$$.$#$$8 $ $ $($* 83674 2.2 Objective!(*D#$:8$($* $##$ $$ 8 #$ $ $$( 8$8#8$( $ $:* * 8 $$ $# 2.3 Criteria!(=#$8#$$*#$($* $(8/< -!(#$ $$$$ -!( $88$(8/#$ <!*8 $!* (!(:,+$. (($(3>*!*#$$ $(8# 8$( $$ #$ #$ ::=$ #$ ::# $#$($* 2.4 Contents!( $* #$ 8$ *$ $( D $ $ / #8#8$*$$(#$ 8$ *$ $ : $(#$ ##$< - $ -. - C8# $#$ -!8#$ - : - 8$ - $(# - ; #$ 367425434.68)9

#8#8$*$#$ # < -!(#(#$ $# 8 $( /(#( $( #$( $( 8$ $*: -!( "<.(A##<$($8$(( $(=$5# -<$($8$(( $(5# $(=$$( $8$( $<$($8$(( $($($ -!($# 8$(#$ $$8# $#$8#$A$8 -$$* :$ +$(/ -!(###2###8$ -!(# =# - 8$$(/$(#$( *$#$#$#$/$ - 8$$8$8$ $8$ :8$(:# < - $$8#<!(#$:$(:# $(#$/!(=$::$(#$#(*"#:$(!( $$#$: # : - <!(#$$$/!(# $:#$$ $ # ##FG/ ($($/ #$ - $#$8#$A$8<!($88#$# $#$$!(8#$$ ( $$$8//!(#$$ $($8*8#$* - :$<!($8:$* 8 : / - +$(/<!( *2# $8#$ #( ($$#, $8$(8$$(( * 8$( $$ $# :$( 1 $( $ 2.5 The use of EGIG Data!(*D#$:8$( $ (/$(#$$8 $ $* 8 $ /(#( 8/ # $#$ #$$##$# $($##$$ $8$( /( $#$#/*$ 367425434.348)9

(:#$* ( $$ $# 8$:88$$$: $( $ $( $$ $# 8$(/($* $)4 *$ $( $$$ $$ $# 8$( $942542342 $(> ::$$ $* $$($:$($(8 $$ $# $(::8: ( /*$$( 8 $#54!( 8$ $# $( $$ $# *$8$($/(#(/$ $*!($* 88 ::/8$(88=# 8$( $ $$: 8$$( $*$8#$ $ $ / $(# *$ $ 88 $( *$ 8 #$ $(/ /$($($* $ *$ $* ($(#$ 8=# 8)52#( $ $* ( $( #$ 8=# 8 /$( / $(# 8 3> *$ $ $ * $##$ $( #$ 8=# 8 $()52#( /$(/$(# 83> 367425434.338)9

3 ANALYSES AND RESULTS 3.1 Definitions!(*D#$:8$ $$ $# $$$$(8$#$$($ $/## 8$( $($8/(#($( $!( $$ $# * $(##$8#$ #( 88=# $**$!(88=# ##$*:$(*8#$ *$(!( $ $ $/ 888=# $($( #!(8$$( $ 8$$$ #$:!( $ 8*/ - $($(8$*$ $ $ 2 HEI<#( # $$$(8$ :> 83444$ $(>$ 3444 >444E -!($$ $ $( 8*:##$8$(#$ $ -!($ $ $( ##$ $ $# $(8#:#!(88=# ##$*:$(*8#$ * $ $ $$ #$ $ >2 : :( * $#!( >2 :: $($$(##$ (:*8:$(>: = $!/ $$ $#$ $( $#8#$: < - #8#$:: $$8: /(#( $# / $ $ $( $$ *##$ 8 : $ 8 $ $( $ #8#$:8 6>@ 8$(##$ 8 8=# - $( # 8 / (/ $( 88#$ 8 # ( *#$$ $$(#$8$(8 $( $(88=#!( / *#$(8 8=# 888$#$.$#$(88#$8# # $ :$( $ 3.2 Trends of the European gas transmission system!( (: 8$$($ 8$( $ $$$ (/ $(:$8$( *$ /(#( $ $$* $J # $#$!( (: #$8$( $ $83674$$( $ 367425434.358)9

3.2.1 Total length!($$$(8$( $ $ # $$ # 5447$($(/ =$356736 $39>5335434 $((/* /$#$( $9 $#* $($$( $ /$(8$( $$(!(:$8$($$$(8$( $ (/ :#$ $ $#8 5$1 14, 12, 1, Length [km] 8, 6, 4, 2, 197 1971 1972 1973 1974 1975 1976 1977 1978 1979 198 1981 1982 1983 1984 1985 1986 1987 1988 1989 199 1991 1992 1993 1994 1995 1996 1997 1998 1999 2 21 22 23 24 25 26 27 28 29 21 Year [-] # * 3 (/ # $($(8$( $ $ /(#(( 8#$ $#( $( 367>3663366154495447!( #( # $/* D$(8#$$( /#:*$>4@8 367425434.398)9

Unknown diameter < 5'' 5" diameter < 11" 11" diameter < 17" 17" diameter < 23" 23" diameter < 29" 29" diameter < 35" 35" diameter < 41" 41" diameter < 47" diameter 47" Length [km] 14, 12, 1, 8, 6, 4, 2, 197 1971 1972 1973 1974 1975 1976 1977 1978 1979 198 1981 1982 1983 1984 1985 1986 1987 1988 1989 199 1991 1992 1993 1994 1995 1996 1997 1998 1999 2 21 22 23 24 25 26 27 28 29 21 Year [-] & ') 5 $$ $($$(>JKL33J$(33JKL37J# $$( $ # Unknown year < 1954 1954 year 1963 1964 year 1973 1974 year 1983 1984 year 1993 1994 year 23 year 24 15, 125, Length [km] 1, 75, 5, 25, 197 1971 1972 1973 1974 1975 1976 1977 1978 1979 198 1981 1982 1983 1984 1985 1986 1987 1988 1989 199 1991 1992 1993 1994 1995 1996 1997 1998 1999 2 21 22 23 24 25 26 27 28 29 21 Year [-] 3 * 9 (/ $($ /*$$(36?)23679$($( 8#$#** :/(#( $($ $8$( $$ 367425434.3)8)9

Unknown Coal tar Bitumen Polyethylene Epoxy Other 14, 12, 1, Length [km] 8, 6, 4, 2, 197 1971 1972 1973 1974 1975 1976 1977 1978 1979 198 1981 1982 1983 1984 1985 1986 1987 1988 1989 199 1991 1992 1993 1994 1995 1996 1997 1998 1999 2 21 22 23 24 25 26 27 28 29 21 Year [-] % * ) (/ $($#$*$$(/ $( $# #$ /$(##8$( $544)8$( $/$( /#$$#** : 14, 12, 1, Unknown cd < 8 cm 8 cm cd 1 cm cd > 1 cm Under water Length [km] 8, 6, 4, 2, 197 1971 1972 1973 1974 1975 1976 1977 1978 1979 198 1981 1982 1983 1984 1985 1986 1987 1988 1989 199 1991 1992 1993 1994 1995 1996 1997 1998 1999 2 21 22 23 24 25 26 27 28 29 21 Year [-] 4 (') > (/ $($ $8$( /$($(8#: $(14#!($ *: $($ $# # $(8#: 8$( 367425434.3>8)9

$ $$ 8 8# $ $ $8#!( #* 8 # 8 $( $(/$($(8#:$(3$ Unknown wt 5 mm 14, 12, 1, 5 mm < wt 1 mm 1 mm < wt 15 mm 15 mm < wt 2 mm 2 mm < wt 25 mm 25 mm < wt 3 mm wt > 3 mm Length [km] 8, 6, 4, 2, 197 1971 1972 1973 1974 1975 1976 1977 1978 1979 198 1981 1982 1983 1984 1985 1986 1987 1988 1989 199 1991 1992 1993 1994 1995 1996 1997 1998 1999 2 21 22 23 24 25 26 27 28 29 21 Year [-] ;.<'.)? (/ $($$( $# /$(# >$34!(8 (/ $# /$($ $*$8$(/$(# # #$ 8$(K># /(#(( # $$ #5443 14, 12, 1, Unknown Grade A Grade B X42 X46 X52 X56 X6 X65 X7 X8 Other Length [km] 8, 6, 4, 2, 197 1971 1972 1973 1974 1975 1976 1977 1978 1979 198 1981 1982 1983 1984 1985 1986 1987 1988 1989 199 1991 1992 1993 1994 1995 1996 1997 1998 1999 2 21 22 23 24 25 26 27 28 29 21 Year [-] = 367425434.3?8)9

7 $$ $($$( 8$$<B>5 B?4!$($( $$?5@8$($$ 14, 12, 1, Unknown p 15 bar 15 < p 25 bar 25 < p 35 bar 35 < p 45 bar 45 < p 55 bar 55 < p 65 bar 65 < p 75 bar p > 75 bar Length [km] 8, 6, 4, 2, 197 1971 1972 1973 1974 1975 1976 1977 1978 1979 198 1981 1982 1983 1984 1985 1986 1987 1988 1989 199 1991 1992 1993 1994 1995 1996 1997 1998 1999 2 21 22 23 24 25 26 27 28 29 21 Year [-] >1?') 1 (/ # 8 $(((, +$.!( $ #$$$( $?>**: 3.2.2 Exposure 6 (/ $(# 8$( :$( # (93 $($(8$*$ $ $ 2 HEI$(367425434$($$ $ / =$9>> E 367425434.378)9

4,, 3,5, 3,, Exposure [km.yr] 2,5, 2,, 1,5, 1,, 5, 197 1971 1972 1973 1974 1975 1976 1977 1978 1979 198 1981 1982 1983 1984 1985 1986 1987 1988 1989 199 1991 1992 1993 1994 1995 1996 1997 1998 1999 2 21 22 23 24 25 26 27 28 29 21 Year [-] 5 (1 3.3 Failure frequencies analyses!( ( /$( $(##$ 8 8$ #$ $( # 88=#!( ##$ 8$$($ <$($$ $ $($ $ $(*8#$ 3.3.1 Number of incidents $( :$( $/(#(#: $( 367425447 $$ 8 3379 #$ / # $( $$( 7?#$ /$*$(* /(#(*$($$ *8#$ $35)68$(36742543434 (/ $(*8#$ 33$(>::8$(#$ #!(8 (/ $(( *# $(>::8$(# # $#$8#$ /($(( *# $$8##$ 35$(#$:*8#$ #$ 367425434.318)9

6 5 Number of incidents [-] 4 3 2 1 197 1971 1972 1973 1974 1975 1976 1977 1978 1979 198 1981 1982 1983 1984 1985 1986 1987 1988 1989 199 1991 1992 1993 1994 1995 1996 1997 1998 1999 2 21 22 23 24 25 26 27 28 29 21 Year [-] #$ " Number of incidents: 5 year moving average 25 2 15 1 5 External interference Corrosion Construction defect / Material failure Hot tap made by error Ground movement Other and unknown 1974 1975 1976 1977 1978 1979 198 1981 1982 1983 1984 1985 1986 1987 1988 1989 199 1991 1992 1993 1994 1995 1996 1997 1998 1999 2 21 22 23 24 25 26 27 28 29 21 Year ## "4*(( 367425434.368)9

1,4 1,2 Number of incidents [-] 1, 8 6 4 2 197 1971 1972 1973 1974 1975 1976 1977 1978 1979 198 1981 1982 1983 1984 1985 1986 1987 1988 1989 199 1991 1992 1993 1994 1995 1996 1997 1998 1999 2 21 22 23 24 25 26 27 28 29 21 Year [-] #& (" 3.3.2 Primary failure frequencies ( 93 $( 8 8=# $( $ 8 $( * 8 #$ 35/$( :* $(# $$ $ 6$( $$(*8#$ : $($$ $!( ( # $( 8 8=# 8 88$ $( $$ 367425434$(# $$( :$($3674254478 )4 94 54 34 $(8$( $> 544?25434!(88=# 8$( :!*3!(6>@#8#$ 8 8$(88=# 8$( :..B3$( $$ $# $( $ $($$(*8#$ 8/. J /..B5 ( " @6A * 1@<B*A * /* #$$$<B* 3674254477 $( $91 3379 93>34 4975 3674254341 $( $)3 35)6 9>>34 49>3 367325434 )4 3555 9>534? 49)7 361325434 94 1?4 94334 451? 366325434 54 )?4 55>34 454) 544325434 34 547 35)34 43?7 544?25434 > 34? 4?>)34 43?5 "# */ 367425434.548)9

5434$(88=#:$($/ =$49>3444E * :$ $($ $( : 8 8=# 49> : $( $ 367425434 ($/$($(88=#8497$$(7 $( 367425447!(88=#:$( $8: / 5434=$43?3444E!(88=#:$( $8: $(8$(88=# :$($ (/$(:8#:#$ 39 (/ $(:$8$(88=# :$($$( $ 8: 39 $$ $( $8$(88=# $(88=# 8$(> ::!(88=#:$($#8 417 3444 E 3674 $ 49> 3444 E 5434!( : : 88=#:8: # *8#$>41?$43?3444E Primary failure frequency: average Primary failure frequency: 5 year moving average 1.4 Failure frequency per 1 km yr 1.2 1.8.6.4.2 197 1971 1972 1973 1974 1975 1976 1977 1978 1979 198 1981 1982 1983 1984 1985 1986 1987 1988 1989 199 1991 1992 1993 1994 1995 1996 1997 1998 1999 2 21 22 23 24 25 26 27 28 29 21 Year [-] #3 */ 88$# (:*$8:!*53) #$/$( $( #$ 8 #$ $( $ $ $8# $( # 8 #$ $$8# $#$8#$A,$8 :$ -$2$* +$(/ $*$ H@I )1) 3?7 3?3 7) )1?? "& "! 367425434.538)9

6 5 Percentage % 4 3 2 1 External interf. Corrosion Constr. defect / Mat. Failure Hot tap made by error Ground movem. Other / Unknown Cause #% " 3>3?: #$:$(88=# 8$($ $$(8$( $8: ::# External interference Corrosion Construction defect / Material failure Hot tap made by error Ground movement Other and unknown Failure frequency per 1 km yr.6.5.4.3.2.1 197 1971 1972 1973 1974 1975 1976 1977 1978 1979 198 1981 1982 1983 1984 1985 1986 1987 1988 1989 199 1991 1992 1993 1994 1995 1996 1997 1998 1999 2 21 22 23 24 25 26 27 28 29 21 Year [-] #4 */'*) 367425434.558)9

5 yr mov. avg. failure frequency per 1 km yr.6.5.4.3.2.1 External interference Corrosion Construction defect / Material failure 1974 1975 1976 1977 1978 1979 198 1981 1982 1983 1984 1985 1986 1987 1988 1989 199 1991 1992 1993 1994 1995 1996 1997 1998 1999 2 21 22 23 24 25 26 27 28 29 21 Year [-] Hot tap made by error Ground movement Other and unknown #; */'46*(() 3> $$ $(#88=#:$(!( ( *$ $#(# :$ #( </ #$#$ $ 2 #$:# 8:$$#$ 8 $(# 8$$8# ##$ #$88=# :$(367425434# $4373444E/($(>2 :: ( :88$433444E #36675449$(>2 :: 8 $( $ $8# # 8 434 $ 44?-/: $ $8# $( # 8 #$ *$ $( 88# /$( #$ 8 $( # ## # $#$8#$ A$8 :$ $( :$ 8 $ $8# #$ *$ $(( $$ 8#$ 8 $( #$ 8 2# $ 8 $( #$:$ 8$$ :#$ $( /=$$$ #$:$ /$( $( $ 8 $ #$ * $( # : 8$($(#$(*(8$(#$:$!*9$(88=# $(>::8$( 8=# :8$(54348#8#$:..B3 367425434.598)9

Cause 367425433 3444.88=# >:: 3444 External interference.17.57 Corrosion.57.4 Construction defect / Material failure.59.31 Hot tap made by error.17.11 Ground movement.26.15!*9<.88=# # 37 $$ $(*$/$(# $($8#$$ 8 "8.2 197-21 5 year moving average.18 Failure frequency per 1 km.yr.16.14.12.1.8.6.4.2 External interference Corrosion Construction defect / Material failure Hot tap made by error Ground movement Cause #= */* 367425434.5)8)9

.1 Pinhole/crack Hole Rupture Failure frequency per 1 km yr.9.8.7.6.5.4.3.2.1 External interf. Corrosion Constr. defect / Mat. Failure Hot tap made by error Ground movem. Cause # * /*- C < ' #5=$6&$#$) 31 (/ $($:$(/($(* " ( $ ## * $ $8#/(#( $( $## $ >4@8$(#$ 8/*:$ 3.3.3 Secondary failure frequencies!( # 8 8=# ##$* : $( * 8 #$ * $ $.$ $ 8$( $$ $# 8# $#$!(##$ 8 # 8 8=# $# $( 8# 8 M $ J $$(8#:$#$(# # =# 8$( #$ # :$ 8 $( $* $( $ $ # 8 8=# (:*##$##$$(8/ $ < - $ $8#< $( $ 8 $( $( $( 8#: $(/ $(# - <$(8# $#$$($8#$$(/$(# - $#$8#$A$8<$(8# $#$ - -$$*<$($8$( - :$<$($8$( - +$(/<# :$ $( /# $( :$# $ $ 367425434.5>8)9

3.3.3.1 Relation between external interference, size of leak and design parameter 36$5) (/$($*$/$(# =# 8$(#$ # * $$8# $($8$($($(8#:$(/$(# $( $8#( $$/( # $#$<$(8 $( $ $( $8#(8$(# /$( $ $( #( : 8$( */8$(:# 8#$8$( " $(($(( $ $$ $*$#$($$( $ #$=$$$:#$ *$/$ (:* $.6 Failure frequency per 1 km yr.5.4.3.2.1 <5 5d<11 11d<17 17d<23 23d<29 29d<35 35d<41 41d<47 d47 Diameter class [inches] #5 1').25 Unknown Pinhole/crack Hole Rupture Failure frequency per 1 km yr.2.15.1.5 <5 5d<11 11d<17 17d<23 23d<29 29d<35 35d<41 41d<47 d47 Nominal diameter ["] &$ 1-C<') 367425434.5?8)9

.7 Failure frequency per 1 km yr.6.5.4.3.2.1 cd<8 8 cd 1 cd>1 Above ground Cover depth [cm] &# 1(').4 Unknown Pinhole/crack Hole Rupture Failure frequency per 1 km yr.35.3.25.2.15.1.5 cd<8 8 cd 1 cd>1 Above ground Cover class [cm] && 1 - C < (') 367425434.578)9

.5 Failure frequency per 1 km yr.4.3.2.1 wt5 5<wt1 1<wt15 15<wt2 2<wt25 25<wt3 wt>3 Nominal wall thickness [mm] &3 1.<'.).25 Unknown Pinhole/crack Hole Rupture Failure frequency per 1 km yr.2.15.1.5 wt5 5<wt1 1<wt15 15<wt2 2<wt25 25<wt3 wt>3 Nominal wall thickness [mm] &% 1 - C <. <'.) $( 8 ## #*/<!( 8 $## 36 $($ $ :* $ $ $8# $(* $!( #* * $( 8#$ 367425434.518)9

$($ $ #* ( / $( * $( # $($$( $# 8$/$$( /$(#!( ### $($$($(8#: 8$(#$ 8$( 88=# 8!( $($ /$($(#: /(:/88=#53 $ $($/$(# 88#$:$#$: $$(#$8 $$8#!( :#$ $ ( ## $ /$( $ $: #:$(/$($( /$( /$(# 54555) 3.3.3.2 Relation between corrosion, size of leak and design parameter 5> $ 94 (/ $( $*$/ $( 8 8=# 8 #$ # * # $(8# $#$8$($($8#$$(/$(#!(88=# 8$( $ $ 8#$8$( ".25 Failure frequency per 1 km yr.2.15.1.5 yr<54 54yr63 64yr73 74yr83 84yr93 94yr3 yr4 Construction year &4 *'*) 367425434.568)9

Failure frequency per 1 km yr.22.2.18.16.14.12.1.8.6.4.2 Unknown Pinhole/crack Hole Rupture yr<54 54yr63 64yr73 74yr83 84yr93 94yr3 yr4 Year of construction &; -C<*'*) Failure frequency per 1 km yr.1.9.8.7.6.5.4.3.2.1 Unknown Coal tar Bitumen Polyethylene Epoxy Coating type &= * 367425434.948)9

.1 Unknown Pinhole/crack Hole Rupture Failure frequency per 1 km yr.9.8.7.6.5.4.3.2.1 Coal tar Bitumen Polyethylene Epoxy Type of coating & -C<* Failure frequency per 1 km yr.13.12.11.1.9.8.7.6.5.4.3.2.1 wt5 5<wt1 1<wt15 15<wt2 2<wt25 25<wt3 wt>3 Nominal wall thickness [mm] &5.<'.) 367425434.938)9

.12 Unknown Pinhole/crack Hole Rupture Failure frequency per 1 km yr.1.8.5.2 wt5 5<wt1 1<wt15 15<wt2 2<wt25 25<wt3 wt>3 Nominal wall thickness [mm] 3$ -C<.<'.) ( *$8 $($( $## 8#$ 3?@31 5>$94 (/$($# 8$ $ " ( ## /( :8/( /* :$##/(#(/ # $#$*836>)!( $/ # *$# 8 8$($ $$8#: 5> $$ $(*$/$(8# $#$8$( $(8 8=# /( 57 (/ $($*$/$( $#$8#$ $( 8 8=# $( 8 $ $($ /$( $ $ #$ /(:((88=# (8$$8$( $ #$8 $(/ $(# *$ $( $( $(# / $( $( 8 56 $$!(8$8$( #(=# $(# $ *8# #$$(8( #(#$* $#$ 88$ $#$: $* / $ :# $( *8#!( 8#$(#$#$#$ #$ : /# $*$#$$ $!($ 8# (:* *$(<$# $# # /$(/# $# #$$$($ 8#8$( /( $# #$ $ $( $ 8# 8 $( % $ 5434 $( $< $ $*$8# #$ H@I $ $ 19 39 %/ ) "% "! 367425434.958)9

?9@8$(# 8$# / $$$:## $ 3)@ %/# $3)@8$($# #$ /( $ # ##/ *81@$7)@8$($# #$ / # * $ # ## 3.3.3.3 Relation between construction defect, size of leak and design parameter.2 Failure frequency per 1 km yr.18.16.14.12.1.8.6.4.2 yr<54 54yr63 64yr73 74yr83 84yr93 94yr3 yr4 Construction year 3# :*'*) Failure frequency per 1 km yr Unknown Pinhole/crack Hole Rupture.12.11.1.9.8.7.6.5.4.3.2.1 yr<54 54yr63 64yr73 74yr83 84yr93 94yr3 yr4 Year of construction 3& :- C < * '*) 367425434.998)9

93 (/ $($$($( $((($(88=# $# $#$ 8#$A$ $ $($ $( / :* $ # $#$ 8#$A$/(#( $$#(#:$!( (( * * :$( (9)3 9395 (/ $($$(88=#8$(# MN544)J ((!( 88=# # *3#$/$( $8 :(( *$ 3.3.3.4 Relation between hot tap made by error, size of leak and design parameter!($f($$*g $($##$( **$ $.6 Failure frequency per 1 km yr.5.4.3.2.1 <5 5d<11 11d<17 17d<23 23d<29 29d<35 35d<41 41d<47 d47 Nominal diameter ["] 33 "* 99 $$ $($$ :*$($$9) (/ $($$( 8#$$ "8( *$ $ " 8( #/$(: $ 367425434.9)8)9

Unknown Pinhole/crack Hole Rupture.4 Failure frequency per 1 km yr.3.2.1 <5 5d<11 11d<17 17d<23 23d<29 29d<35 35d<41 41d<47 d47 Diameter class [inches] 3% "*-C< 3.3.3.5 Ground movement :$ *87>@8$($$#$ 8$($* 9>9?#$ $($*$/:$ "8$ # :$#$ ## " (/:$ #*## $($ $ :*8:$$($!(* $$($ )7 J # *:$#$!( $$ $($: $ #* 88#$* $( 8# ##* :$#$.5 Failure frequency per 1 km yr.4.3.2.1 <5 5d<11 11d<17 17d<23 23d<29 29d<35 35d<41 41d<47 d47 Nominal diameter ["] 34 ( 367425434.9>8)9

.2 Pinhole/crack Hole Rupture Failure frequency per 1 km yr.1 <5 5d<11 11d<17 17d<23 23d<29 29d<35 35d<41 41d<47 d47 Diameter class [inches] 3; (-C< $(8$#*$$( 8# $ *$((($ $$$ /(#(:$F,:$G!( *2# 8:$< 2; 2 2 : 2, 2* 2 2+$( 2%/ 97 (/ $( $*$8$( *2# $(#$:$ 367425434.9?8)9

6 5 Incident distribution [%] 4 3 2 1 Unknown Dike break Erosion Flood Landslide Mining River Other Ground movement 3= ""6( 3.3.3.6 Other and unknown!(# 8$(#$F+$(/G ($!( *2# ($ $ $5?@8$(#$ /$($( #$ $( $( 367425434 53 #$ $ ($(:* # $( $* /(#( $ 88=#$($=$444>63444E!($( $*$8$(# =# 8($$ 8 " +$853#$ 36/ ( ## 5 $ ( ($ ( #8$ : #$9)9 367425434.978)9

3.4 Other analysis 3.4.1 Ageing!(8#8$(8$( $(88=# ( * $$( $ $( $(88=#8# #$ ( * $ 8#$ 8# $#$.8 yr<54 54yr63 64yr73 74yr83 84yr93 94yr3 yr4.7 Failure frequency per 1 km.yr.6.5.4.3.2.1 yr<5 5yr<1 1yr<15 15yr<2 2yr<25 25yr<3 3yr<35 35yr<4 4yr<45 45yr<5 yr5 Age [year] 3 *') &91!! "!(8 $## 891 $($# $#$ *836?)(: (( 8 8=# $( #$ # $#$ -/: # $$ ## $($88=# #$:8$(#$ ($# $. # $#$# $*836?4 $* *D#$$8 $# ( $#(*# :* $( 36?4 $ $($ $8$/ (:$(( $88 $#. # $#$8 $( 36?)23679# $#$# $ (/ +$ 8 (:$$#$(88=#8$( 367425434.918)9

3.4.2 Detection of incidents!*> (/ $( $*$ 8$($8 $#$!( *# $( $# $#$ /$( $ 97@8 $(#$ % $ 5434 $ 37@ 8$( #$ / $#$* $( $ Detection Incident distribution Public 36.7 Patrol 16.5 Contractor 15.6 Unknown 7.5 Company staff 7.5 Distribution company 4.8 Landowner 4.6 Other 3.3 Client 1.7 On line inspection 1.6 River police.2 "4 Unknown Client Company staff Contractor Distri company Landowner On line inspection Patrol River police Public Other 5 Incident distribution [%] 4 3 2 1 External interf. Corrosion Constr. defect / Mat. Failure Hot tap made by error Ground movem. Other / Unknown Cause 35 367425434.968)9

96 $$ $( $#$ 8 #$ # $#* $($ $ #$ $#$*$(*#$$8#*##$#$ $( $$$ $ 8$#$.$ *$($ # $*88#$: 8$($#$8#$ /$($(# # # $#$8#$ 3.4.3 Ignition probability $$$: $ /(#($ $(# =# 8$(#$ $(367425434)>@8$( # #$ $($* $ $ $( $#8$ #!($* : $( *$$:$$(*$/$ "!*?: $($**$ "8 "8 $**$ H@I.(2## ) - $ 5 39 "; ""<* $ /$($## : #$!( #$(# 8 /$($!*7# (/ $($ 8*$ $ $ $( 8 $ $#* $# $($ $( $ $*(( "8 $L3?#( $ 3?#( $**$ H@I "= ""!!( : $* : $( $ **$ 8 #$ $$( #$: 8 $( # $ *: $($$( **$ :##$$(#!( #8# $$($**$ 8 # *($ +$853 $(367425434# *($35$/(#(* $( $**$8 $($$>7@ 34 99 3.4.4 Injuries and fatalities : $$ $#8$*$88=# # 8#$ 8 $( $#$ 8$$# D :8$$!($* 8#$ =$$:8$*$$(# =# 8#$!($* #$ $$835)6#$ 7# 4?@8$($$( #$ :8$$ $$ $$(*###5# 45@8$($ 367425434.)48)9

!(**$8 :# =# ( *: $/$($(**$8:* / $(88#$ 4 CONCLUSIONS AND FACTS ( $ $( #$ $*! # 8 88$ #$ /##$ #$ $ $(39>4448 :!($$ /(#( $($(8 $ 8$ 9>>E!( $$ $# 8 #$ ##$ $( $* : * 8 8=#!( :#$8=# =$49>#$ 3444:$( 3674$5434!( > : : 8 8=# 5434/(#( $ $( : #$8=#:$( $> = 43?3444!(8::::88=#( ## $$: $( $(($( $$ $*!(((#$*$8$8#( $ $#$$ $($ $$8##$ #(#$ *$$ :# =# $ $8# #$ (: # : $( $($ $( / 8 $$($8# # $#$A$8#$ 5 REFERENCE 7$( $8$(.#$$367425447#*5441 367425434.)38)9

D# #$%$% ( @*A " @6A * 1 @<B*A * /* #$$$<B* 54E * /* #$$$<B* 54E F * /* #$$$<B* 3674254477 $( $91 3379 93>34 4975 49>4 496) 3674254341 $( $)3 35)6 9>>34 49>3 4995 4973 367325434 )4 3555 9>534? 49)7 4951 49?7 361325434 94 1?4 94334 451? 45?7 494> 366325434 54 )?4 55>34 454) 431? 455) 544325434 34 547 35)34 43?7 43)> 4363 544?25434 > 34? 4?>)34 43?5 4399 436? " */(( Cause.8 8=# 3444 6>@;;.8 8=# 3444 6>@%;.8 8=# 3444 External interference.17.157.184 Corrosion.57.49.65 Construction defect / Material failure.59.51.67 Hot tap made by error.17.13.22 Ground movement.26.21.32 "5 */'#5=$6&$#$)54E ( Cause.8 8=# 3444 6>@;;.8 8=# 3444 6>@%;.8 8=# 3444 External interference.57.4.78 Corrosion.4.26.58 Construction defect / Material failure.31.19.47 Hot tap made by error.11.4.22 Ground movement.15.7.28 "#$ 46*((*/ '&$#$) 367425434.)58)9

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