No C 37/2 Official  Journal  of the  European  Communities 10. 2. 79 
II 
(Preparatory  Acts) 
COMMISSION 
Proposal  for a Council  Directive  on the approximation  of the laws  of the Member  States 
relating  to certain  types  of simple  pressure  vessels 
(Submitted  by the Commission  to the Council  on 18 December  1978) 
THE  COUNCIL  OF THE  EUROPEAN 
COMMUNITIES, 
Having  regard  to  the  Treaty  establishing  the 
European  Economic  Community,  and  in particular 
Article  100  thereof, 
Having  regard  to  the  proposal  from  the 
Commission, 
Having  regard  to the  opinion  of the  European 
Parliament, 
Having  regard  to the opinion  of the Economic  and 
Social  Committee, 
Whereas  in  each  Member  State  mandatory 
provisions  determine  the  characteristics  of con-
struction  and  verification  of unfired  welded  steel 
pressure  vessels  of simple  geometry;  whereas  these 
requirements  differ  from  one  Member  State  to 
another;  whereas  such  differences  hinder  trade,  thus 
directly  affecting  the  functioning  of the  common 
market; 
Whereas  Council  Directive  76/767/EEC  (*) of 27 
July 1976  laid  down  in particular  the procedures  of 
EEC  pattern  approval  and  EEC  verification  to which 
such  pressure  vessels  are subject; 
Whereas,  in accordance  with  that  Directive,  it is 
necessary  to determine  the  technical  requirements 
(') OJ No L 262,  27. 9. 1976,  p. 153. which  the said  pressure  vessels  must  satisfy  in order 
to be placed  on the  market  and  taken  into  service 
after  an inspection  and  the affixing  of the prescribed 
marks; 
Whereas,  in order  to take  account  of technical 
progress,  the  technical  requirements  relating  to 
pressure  vessels  must  be adapted  promptly;  whereas 
the procedure  laid  down  in Article  20  of the 
Directive  must  be applied; 
Whereas  pressure  vessels  may  deviate  in design  and 
in the  method  of their  manufacture  from  certain 
requirements,  notably  those  laid  down  in 2.1 to 2.4 
of the  Annex,  provided  that  they  are  no less  safe; 
whereas  the procedure  laid  down  to that  end  in the 
Directive  must  accordingly  be applied, 
HAS  ADOPTED  THIS  DIRECTIVE: 
Article  1 
1. This  Directive  shall  apply  to all  fixed  or 
movable  unfired  welded  steel  pressure  vessels  of 
simple  geometry,  as defined  in Article  2, intended  to 
contain  compressed  air or non-corrosive,  non-toxic 
compressed  gases. 
2. The  pressure  vessels  referred  to in the  first 
paragraph  are hereinafter  called  'vessels'. 
3. The  following  are excluded: 
— specially  designed  vessels  for  the  conveyance  of 
gases, 
10. 2. 79 Official  Journal  of the  European  Communities No C 37/3 
— vessels  intended  to equip  the  brake  circuits  of 
motor  vehicles  and  their  trailers, 
— fire-extinguisher  vessels. 
Article  2 
For the purpose  of this  Directive,  'vessel'  means  any 
vessel: 
(a) — comprising  a right  cylindrical  portion  with 
axisymmetrical  dished  heads  on  the  same 
axis,  the concave  sides  of which  face  inwards, 
or with  flat heads, 
— comprising  two  axisymmetrical  dished  heads 
on the same  axis; 
(b) having  only  circular  penetrations  and  nozzles 
(though  for  cleaning  or inspection  purposes,  in 
particular,  these  may  be elliptical)  with  axes 
perpendicular  to the  wall  of the  cylindrical 
portion  of the vessel  and  sufficiently  far apart  to 
be considered  separately  for  purposes  of stress 
analysis. 
However,  penetrations,  notably  for  drainage 
purposes,  may  be provided  on the walls  of the dished 
heads  as long  as they  are not  more  than  15 mm  in 
diameter.  Such  penetrations  need  not  be perpen-
dicular  to the walls  of the dished  heads. 
The dished  heads  referred  to in this  Article  shall  be 
of one  piece. 
Article  3 
The vessels  referred  to in Article  1 shall  be subject 
to: 
(a) EEC  pattern  approval  and  EEC  verification 
where  the product  of P x V(')  exceeds  200  bar 
x litres; 
(b) EEC  verification  where  the  product  of P x V 
does  not exceed  200  bar x litres. Article  4 
The amendments  necessary  to adapt  the Annex  and 
Appendices  to technical  progress  shall  be adopted  in 
accordance  with  the procedure  laid  down  in Article 
20 of Directive  76/767/EEC. 
Article  5 
Derogations  from  the provisions  of 2.1 to 2.4 of the 
Annex  may  be granted  pursuant  to Article  17 of 
Directive  76/767/EEC. 
Article  6 
No Member  State  shall,  on grounds  relating  to its 
design  and  inspection,  refuse,  prohibit  or restrict  the 
placing  on the  market  and  taking  into  service  of a 
vessel  which  complies  with  the  requirements  of 
Directive  76/767/EEC  and  of the present  Directive. 
Article  7 
1. Each  Member  State  shall,  within  18 months 
after  notification  of this  Directive,  bring  into  force 
the laws,  regulations  and  administrative  provisions 
necessary  in order  to comply  therewith  and  shall 
forthwith  inform  the Commission  thereof. 
2. With  effect  from  the  notification  of this 
Directive,  each  Member  State  shall  ensure  that  every 
draft  law,  regulation  or administrative  provision  that 
it is intended  to adopt  in the  field  covered  by this 
Directive  is notified  to the Commission  in good  time 
to enable  it to comment  thereon. 
Article  8 
(') P = pressure,  V = volume. This  Directive  is addressed  to the Member  States. 
No C 37/4 Official  Journal  of the  European  Communities 10. 2. 79 
TECHNICAL  ANNEX 
CHAPTER  I 
DESIGN  OF  VESSELS 
1. Limits  of application 
The technical  Annex  of this  Directive  applies  to the  vessels  referred  to in Article  1 for 
which: 
— the  maximum  working  pressure  does  not exceed  30 bar, 
— the  volume  does  not exceed  3 000  litres, 
— the  product  P x V does  not exceed  10 000 bar x litres, 
— the  actual  thickness  of the shell  rings  and  dished  ends  does  not exceed  16 mm, 
— the  actual  thickness  of the shell  rings  and  dished  ends  is not less  than  2 mm, 
— the  actual  thickness  of the flat  end  plates  does  not exceed  25 mm, 
— the  length  of the cylindrical  part  does  not exceed  12 times  its average  diameter, 
— the  diameter  of the  openings  does  not  exceed  0'3  times  the  average  diameter  of the 
cylindrical  part, 
— the  diameter  of the flanges  does  not exceed  300  mm, 
— the  circular  or elliptical  inspection  openings  do not  exceed  400  mm  at their  widest 
point, 
— the  minimum  working  temperature  is not less  than  — 20 or — 10 °C, 
— the  maximum  working  temperature  does  not exceed  + 300  °C. 
• 2. Materials 
Castings  may  not  under  any  circumstances  be used  for  the manufacture  of the  pressure 
parts. 
2.1. Pressure  parts 
The steels  used  for  the  fabrication  of the  pressure  parts  must  meet  the  following 
conditions. 
2.1.1.  Vessels  required  to have  a minimum  working  temperature  of—  20 °C. 
The grades  and  qualities  of steel  required  are as follows: 
(a) plate 
Euronorm  28-69:  Fe  37-2  kW;  Fe 37-2  kP;  Fe 42-2  kW; 
Fe 42-2  kP;  Fe 47-2  kW;  Fe 47-2  kP; 
(b) seamless  tubes 
standard  ISO/2604/11-1975:  TS  6; TS 10;  TS 15; 
(c) welded  tubes 
standard  ISO/2604/111-1975:  TW6;TW  10;TW  15; 
(d) forgings 
standard  ISO/2604/1-1975:  F  9; 
(e) projections 
Euronorm  25-72:  Fe  360  D; Fe 430  D. 
f 
10. 2. 79 Official  Journal  of the  European  Communities No C 37/5 
2.1.2.  Vessels  required  to have  a minimum  working  temperature  of — 10 °C.  • 
The grades  and  qualities  of steel  required  are as follows: 
(a) plate 
Euronorm  28-69:  Fe  37; Fe 42; 
(b) seamless  tubes 
standard  ISO/2604/11-1975:  TS  4; TS 6; TS 10; 
TS 13;  TS 14;  TS 15; 
(c) welded  tubes 
standard  ISO/2604/111-1975:  TW  4, TW  5, TW  6, TW  9; 
TW 10; TW  13; TW  14; TW  15; 
(d) forgings 
standard  ISO/2604/1-1975:  F  8; F 9; 
(e) projections 
Euronorm  25-72:  Fe  310;  Fe 360;  Fe 430. 
2.2. Welded  flanges:  these  shall  be made  of steel  of the grade  and  quality  specified  in 2.1 or of 
a carbon  or carbon-manganese  steel  of which  the  chemical  composition  of the  melt  and 
the mechanical  properties  fall  within  the limit  values  shown  in the table  below. 
°/„C % Mn VoSi °/„S Rg max. RR max. Elongation 
or % P RR max. 
max. max. max. max. N/mm! _N/mm' min.  (%) 
0-20 1-6 0-40 0-05 265 440 22 
2.3. Fastenings 
The bolts,  screws,  studs  and  nuts  must  conform  to the  specifications  of ISO  standards 
R898/I  — 1968,  R898/II  — 1969  and  898/IV  — 1972. 
The categories  of steel  specified  in these  standards  may  be used  provided  that  the 
minimum  elongation  after  rupture  of these  steels  is not less  than  16 %. 
2.4. Attachments 
All unpressurized  parts  welded  to the  body  of the  vessel  shall  be of materials  compatible 
with  the steel  of the vessel  to which  they  are welded. 
2.5. Ordering 
2.5.1.  When  ordering  the  base  materials,  the  vessel  manufacturer  shall  specify  the  type  of 
product  together  with  its dimensions,  characteristic  and  the grade  and  quality  of the steel. 
2.5.2.  He  shall  also  specify  the  type  of documents  which  must  accompany  the  delivery  in 
accordance  with  2.6 of this  Directive. 
2.6. Type  of documents 
2.6.1.  Inspection  certificate 
The inspection  certificate  in accordance  with  the  provisions  of Euronorm  21-76  is 
required  for the steel  specified  in 2.1. 
2.6.2.  Certificate  of conformity  with  the order 
The certificate  of conformity  with  the  order,  in accordance  with  the  provisions  of 
Euronorm  21-76,  is required  for  the steels  specified  in 2.2 and  the  products  referred  to in 
2.4 of this  Directive. 
No C 37/6 Official  Journal  of the  European  Communities 10. 2. 79 
2.6.3.  The  documents  referred  to in 2.6.1  and  2.6.2  shall  indicate  the  marks  affixed  to the 
products  delivered  in such  a way  that  the documents  can  be correlated  with  the products 
without  risk  of error. 
2.7. ' Identification 
All the products  used  in the manufacture  of the pressure  vessels  shall  be identifiable. 
3. Calculation  of pressure  parts 
3.1. Definitions 
3.1.1.  Design  pressure 
This is the pressure  value.  selected  by the manufacturer,  on his own  responsibility,  and 
used in the formulae  for calculating  the pressure  parts. 
3.1.2.  Design  temperature 
This  is a temperature  value  selected  by the manufacturer  on his own  responsibility.  It 
enables  the stress  value  to be determined  at the temperature  concerned. 
3.2. Thickness  of the pressure  parts 
The thickness  of the  pressure  parts  shall  not  be less  than  those  calculated  with  the 
formulae  given  in Annex  I. 
In these  formulae  no allowance  is made  for corrosion  thickness.  If, however,  an allowance 
is made  for extra  thickness  to take  account  of corrosion,  the amount  of such  an allowance 
shall  be indicated  on the data  plate  affixed  to the vessel. 
3.2.1.  The  permissible  stress  f to be used  in the formulae  for calculating  the pressure  parts  shall 
be whichever  is the lower  of the following  values: 
The yield  strength  RET  used  to calculate  the permissible  stress  of the parts  under  pressure 
shall  be one of the following  values: 
— when  a steel  does  not have  an upper  and  lower  yield  point,  the normal  proof  stress 
R0 2 is taken, 
— when  a steel  has a lower  and upper  yield  point,  the value  to be taken  is either: 
— ReL 
or 
0 92 ReH  provided  that  the value  ReH  has  been  determined  from  the load-extension 
diagram, 
or 
R0.2, 
— when  the design  temperature  is above  50 °C, the yield  strength  is taken  as the 0 2 % 
proof  stress  at the temperature  concerned. 
3.2.2. For butt  welds  the coefficient  z used  to calculate  the pressure  parts  shall  be taken  as equal 
to: 
— z = 1; z = 0 85 or z = 0 7. 
10.2.79 Official  Journal  of the  European  Communities No C 37/7 
CHAPTER  II 
MANUFACTURE  VESSEL 
4. General 
4.1. The  base  products,  the  filler  products,  the  welding  and  fabricating  processes  and  the 
inspection  methods  shall  be such  as to ensure  that  the  vessels  produced  satisfy  the 
requirements  of this  Directive. 
4.2. The  welding  techniques  employed  must  have  undergone  an acceptance  test  beforehand  in 
accordance  with  the provisions  of Annex  III. 
4.3. The  welds  must  be effected  by welders  who  are  qualified  in accordance  with  the 
provisions  of Annex  V. 
4.4. Any  welding  procedure  ensuring  complete  penetration  is permissible. 
4.5. Inspection  holes  and  flanges 
If inspection  holes  or flanges  are required,  they  shall  be carried  out  in accordance  with 
the specifications  in sections  5 and 6 of Annex  I. 
5. Preparation  and  welding  of assemblies  under  pressure 
5.1, Forming  of the plate 
The forming  of the plate  shall  not give  rise to defects  that  might  be detrimental  to safety. 
A forming  process  during  which  the temperature  of the metal  is below  the transformation 
point  AC)  is known  as cold  forming. 
In the case  of cold  forming,  if the value 
x 100  is greater  than  3 
normalizing  heat  treatment  must  be given. 
er: actual  thickness  of the plate, 
rj: the smallest  radius  of curvature. 
5.2. Bevelling  of plate 
Where  plates  of different  thickness  are  welded  by a circumferential  butt  weld,  the 
thickness  plate  must  be bevelled  over  a length  not  less  than  three  times  the width  of the 
bevel. 
5.3. Welding  of plate 
Only  butt  welds  with  complete  penetration  are  permissible  for  the  circumferential  and 
longitudinal  welds. 
However,  circumferential  welds  with  hammered  edges  are permissible  if the thickness  of 
the plates  does  not exceed  8 mm. 
For longitudinal  joints,  if a backing  plate  is used  it must  be removed  after  welding  and 
before  non-destructive  testing. 
For circumferential  joints,  if a backing  plate  is used  and  cannot  be removed,  satisfactory 
penetration  of the backing  plate  must  be ensured. 
When  backing  plates  are removed,  they  must  not cause  excessive  deformation. 
The material  of the  backing  plate  must  be a kind  which  does  not  adversely  affect  the 
weld. 
Connections  between  nozzles  or penetrations  and  the shell  ring  and  between  the shell  ring 
and/or  the flat  end  plates  in the case  of fillet  welds  shall  be such  as to ensure  complete 
fusion  at the root. 
No C 37/8 Official  Journal  of the  European  Communities 10. 2. 79 
5.4. Alignment  of the plates 
5.4.1.  For  longitudinal  joints  and  for circumferential  joints  welded  on one  side  only,  the median 
axes of the plates  shall  be aligned  with  a tolerance  of ± 10 % of the thickness  of the 
thickest  plate. 
In the case  of a circumferential  joint  welded  in both  sides,  a larger  tolerance  is permissible 
provided  a sound  bead  is obtained  on the other  side. 
5.4.2.  Alignment  of surfaces  with  plates  of different  thicknesses. 
The maximum  error  in the alignment  of the surfaces  of the plates  is one  quarter  of the 
thickness  of the thickest  plate. 
If this  error  is exceeded,  the surface  shall  be bevelled  in accordance  with  the specifications 
in 5.2. 
_o _o 
_0. 
-<U 
Longitudinal  joints Circumferential  joints 
bl < e 710 Welded  on one  side  only:  b,<e  710 
Welded  on two  sides:  no limit 
b2 < e 74 for e ' < 16 mm b2 < e 74 if e ' < 16 mm 
hi < 3 mm for e ' < 16 mm 
5.5. Appearance  of weld  bead 
All welds  must  have  a regular  surface  and  display  no lack  of thickness;  they  must  blend 
with the surfaces  of the plates  without  undercuts  or unacceptable  faults. 
The weld  reinforcement  must  not  exceed  the  higher  of the  following  two  values:  one 
tenth  of the width  of the bead  or 1 mm.  A double  reinforcement  is permissible  at the point 
of overlap  at the end of the bead. 
The maximum  height  of the sealing  run bead,  if any,  is the higher  of the following  two 
values:  one tenth  of the thickness  of the plate  or 1 mm. 
10.2.79 Official  Journal  of the  European  Communities No C 37/9 
5.6. Repairs  to welds 
The weld  must  be entirely  renewed  after  removal  of the defective  section  and  not repaired 
by refilling. 
With  the exception  of local  retouching  by manual  welding,  all repairs  must  be carried  out 
by the same  process  as used  for the original  weld. 
No other  process  may  be used  until  the inspection  authorities  have  been  notified,  have 
given  their  consent  and have  approved  the process. 
5.7. Shape  tolerance 
5.7.1.  Ovality 
The defect  of ovality  is defined  by the difference  between  the maximum  and  minimum 
diameters  divided  by half  their  sum. 
This ratio  must  not exceed  1 % in any  cross  section  of the vessel.  At the nozzle  locations, 
however,  an ovality  of up to 2 % is acceptable. 
5.7.2.  Straightness 
The deflection  of any  generatrix  of the cylindrical  part  of the vessel  when  empty  and  not 
under  pressure  must  not exceed  0 3 %. 
5.7.3.  Irregularities  of profile 
Irregularities  in the profile  (checked  by means  of a gauge  with  a 20° aperture)  must  not 
exceed  5 % of the minimum  thickness  of the plate  plus  3 mm.  This  maximum  value  shall 
be increased  by 25 % if the length  of the irregularity  does  not exceed  one  quarter  of the 
length  of the cylindrical  shell  component  contained  between  two  circumferential  joints, 
with a maximum  of 1 m. 
6. Welding  of accessories  not subject  to pressure 
The design  of accessories  such  as supports,  handles,  hoisting  eyes,  stiffeners,  etc. must  be 
such as to allow  them  to be welded  to pressure  parts.  Welding  must  be carried  out  in 
accordance  with  the specifications  in 5.5. 
CHAPTER  III 
EEC  PATTERN  APPROVAL 
7. Application  for EEC  pattern  approval 
The application  and  the correspondence  relating  to it must  comply  with  the requirements 
laid down  in section  1 of Annex  I to Council  Directive  76/767/EEC  of 27 July  1976. 
8. Examination  for EEC  pattern  approval 
8.1. The  examination  for  EEC  pattern  approval  shall  be carried  out  on the  basis  of the 
technical  file and specimen  vessels. 
8.2. —  The  applicant  shall  make  available  10 vessels  representative  of the planned  production. 
The inspection  body  shall  select  three  vessels  on which  the prescribed  verification  and 
tests will be carried  out. 
However,  for vessels  produced  in small  quantities,  the applicant  shall  make  available 
the number  of vessels  required  for  the  verifications  and  tests  stipulated  in this 
Directive. 
— For  vessels  to be produced  in small  quantities,  the applicant  shall  make  available  the 
number  of vessels  considered  necessary  by the inspection  body  for the verifications  and 
tests stipulated  in this Directive. 
No C 37/10 Official  Journal  of the  European  Communities 10. 2. 79 
8.3. Examination  of the technical  file 
This  examination  shall  include: 
(a) verification  that  the steels  have  been  selected  in accordance  with  the requirements  laid 
down  in 2.1,  2.2,  2.3 and 2.4; 
(b) checking  of the conformity  documents  specified  in 2.6; 
(c) checking  of the design  of the vessels  in accordance  with  the requirements  laid  down  in 
Annex  I, sections  5 and 6; 
(d) checking  of the location  provided  for the EEC  marks  and  inscriptions  in accordance 
with Chapter  V; 
(e) verification  of the certificates  for the welding  technique  and  the welders'  qualifications 
required  for the welding  methods  to be used  for production; 
(f) verification  that  the design  calculations  have  been  carried  out in accordance  with  the 
requirements  laid  down  in section  3 and in Annex  I, sections  1,2,3  and  4. 
8.4. Inspections  and tests  to be performed  on finished  vessels. 
8.4.1.  Test  on finished  vessels 
(a) 100  % radiographic  examination  of the butt  welds  on the vessels  made  available  to the 
inspection  body; 
(b) one  hydrostatic  test on each  vessel  selected  by the inspection  body; 
(c) a pressure  cycling  test on one  vessel  of the vessel  to be produced  have  flat  end plates 
and fillet  welds. 
8.4.2.  Checks  on good  workmanship 
The checks  on good  workmanship  shall  include  in particular: 
— checking  of the design  of the welded  joints  in accordance  with  the requirements  of 
sections  4, 5 and 6, 
— checking  of the thickness  of the pressure  parts  in accordance  with  the requirements  of 
section  3 and of Annex  I, sections  1,2,3  and  4. 
8.5. Inspections  and tests  to be performed  on specimens  taken  from  a finished  vessel. 
The specimens  shall  be taken  at the factory  by the manufacturer  in the presence  of the 
inspection  body. 
8.5.1.  Tests  on rings 
The following  tests  shall  be carried  out on the rings  which  have  been  heat-treated: 
(a) one  tensile  test; 
(b) three  impact  tests. 
8.5.2.  Test  on vessel  ends 
The following  tests  shall  be carried  out on vessel  ends  in all cases: 
(a) one  tensile  test; 
(b) three  impact  tests. 
8.5.3.  Test  to be performed  on welds 
8.5.3.1.  Longitudinal  and  circumferential  welds 
The following  tests  shall  be performed,  at the discretion  of the inspection  body,  on either 
the longitudinal  welds  or the circumferential  welds  when  the welding  technique  used  is 
the same  for both. 
When  this  is not  the  case,  the  tests  shall  be performed  on both  circumferential  and 
longitudinal  welds 
(a) one  tensile  test (perpendicular  to the weld); 
(b) one  bend  test on the underside  of the weld; 
10. 2. 79 Official  Journal  of the  European  Communities No C 37/11 
(c) one  bend  test on the upper  side  of the weld; 
(d) three  impact  tests  in the weld; 
(e) three  impact  tests  in the heat-affected  zone  limited  according  to the  diameter  and 
thickness  of the ring; 
(f) one  hardness  test;  , 
(g) one  macrographic  examination. 
8.5.3.2.  Nozzle,  penetration  and  ring/flat-end  welds 
Ultrasonic  inspection  of these  welds  shall  be performed  on each  vessel  made  available  to 
the inspection  body. 
A macrographic  examination  shall  be carried  out on nozzle  and  penetration  welds. 
This examination  shall  also  be carried  out  on ring/flat-end  welds  where  a fillet  weld  is 
used. 
8.5.4.  The  impact  tests  for EEC  pattern  approval  shall  be carried  out at — 20 °C if the minimum 
working  temperature  is — 20 ° C and  at 0 ° C if the  minimum  working  temperature  is 
-10°C. 
These  tests  shall  be carried  out if the plate  is more  than  5 mm thick. 
9. EEC  pattern  approval  certificate  and mark 
The EEC  pattern  approval  certificate  and the accompanying  technical  file must  reproduce 
the requirements  specified  in section  3 of Annex  I to Council  Directive  76/767/EEC. 
The certificate  must  be in accordance  with  the  specimen  set out  in Annex  VI to this 
Directive. 
The certificate  must  contain  in particular: 
— the  conclusions  of the pattern  examination, 
— the expiry  date  of the EEC  pattern  approval  in accordance  with  10.3, 
— the conditions  which  must  be satisfied  by the variants  of a vessel  in order  that  they 
may be covered  by the same  EEC  pattern  approval  in accordance  with  10.2, 
— the marks  relating  to the EEC  pattern  approval  in accordance  with  section  5 of Annex 
I to Council  Directive  76/767/EEC  and  14.1  of this Directive. 
10. Characteristics  of vessels  covered  by the same  EEC  type  approval 
10.1.  EEC  type  approval  may  be granted  for vessels  consisting  of: 
(a) two  ends  and one  or more  rings;  or 
(b) two  dished  ends  for which  a cylindrical  edge  is provided  in accordance  with  the 
requirements  of section  2 of Annex  I. 
10.2.  The  EEC  pattern  approval  granted  for one  model  of vessel  may  cover  variants  of this 
model. 
A family  of vessels  consists  of one  or more  variants. 
Vessels  which  differ  from  the  model  only  in diameter  and/or  in the  length  of their 
cylindrical  part  within  the following  limits  form  part  of the same  family: 
(a) Variations  in diameter 
— variations  in diameter  are permitted  but the actual  thicknesses  of the walls  of the 
vessels  in any  one  family  must  be identical  to the thicknesses  of the walls  of the 
model, 
No C 37/12 Official  Journal  of the  European  Communities 10. 2. 79 
— variations  must  meet  the requirements  in 3.2, 
— the conditions  regarding  heat  treatment  in 5.1 must  be observed; 
(b) Variations  in the length  of the cylindrical  part 
— When  the model  consists  of one  or more  shell  rings  in addition  to the ends,  vessels 
in the same  family  must  also  consist  of one  or more  shell  rings, 
— when  the model  consists  solely  of two  dished  ends  in accordance  with  10.1  (b), 
vessels  in the same  family  may  not under  any  circumstances  contain  one  or more 
shell  rings, 
— if variations  in the length  of the vessel  involve  modifications  in respect  of openings 
and penetrations  (number,  dimensions,  spacing),  these  modifications  shall  be 
shown  on the drawing  of each  variant  submitted  with  the application  for pattern 
approval  and must  meet  the conditions  laid  down  in this Directive. 
10.3.  The  period  of validity  of an EEC  pattern  approval  certificate  for these  vessels  shall  be: 
(a) vessels  subject  to pattern  approval: 
— five  years,  which  may  be extended  by the Member  State  granting  approval  for 
successive  periods  of a maximum  of five  years; 
(b) vessels  subject  to pattern  approval  and  verification: 
— 10 years,  which  may  be extended  by the  Member  State  granting  approval  for 
successive  periods  of a maximum  of 10 years. 
CHAPTER  IV 
EEC  PATTERN  VERIFICATION 
11. Examination  for conformity  to an approved  pattern 
At the time  of EEC  verification,  the inspection  body  shall  verify  that  each  vessel  in the 
batch  conforms  to the approved  pattern,  particularly  as regards: 
— the principal  dimensions,  the specified  inscriptions,  the pattern  approval  mark  and  the 
location  provided  for the EEC  verification  marks  in accordance  with  section  14, 
— the validity  of the certificates  obtained  regarding  approval  of the welding  technique(s) 
and the qualifications  of the welders, 
— the requirements  specified  in 5.4 to 5.7, 
— the inspection  body  shall  verify  that  the materials  used  are as specified  in the technical 
file accompanying  the  EEC  pattern  approval  certificate  in accordance  with  the 
requirements  in 2.7. 
12. Test  to be performed  on coupon  plates 
The coupon  plate  shall  be taken  in the presence  of the inspection  body. 
For each  batch  or part  of 25 vessels  built,  a coupon  plate  representative  of the batch  or 
part thereof  shall  be supplied. 
For mass  production,  the number  of vessels  per batch  shall  be decided  by the inspection 
body. 
The dimensions  of the  coupon  plate  shall  be such  that  it is possible  to take  from  it a 
sufficient  number  of test pieces  on which  to perform  the specified  tests. 
10. 2. 79 Official  Journal  of the  European  Communities No C 37/13 
12.1.  Tests  on welds 
The following  test shall  be carried  out: 
(a) one  tensile  test (perpendicular  to the weld); 
(b) one  bend  test on the underside  of the weld; 
(c) one  bend  test on the upper  side  of the weld; 
(d) three  impact  tests  in the weld. 
— When  a different  welding  technique  is used  for longitudinal  and  circumferential 
welds,  these  tests  shall  be carried  out on both  types  of weld, 
— when  the same  technique  is used  for longitudinal  and  circumferential  welds,  these 
tests shall  be carried  out  on the  longitudinal  welds  in each  batch  and  on the 
circumferential  welds  in every  second  batch, 
— the impact  tests  stipulated  for  EEC  pattern  verification  shall  be carried  out  at 
— 20 °C if the  minimum  working  temperature  is — 20 °C and  at 0 °C if the 
minimum  working  temperature  is — 10 °C. 
These  tests  shall  be carried  out if the plate  is more  than  5 mm thick. 
13. Non-destructive  testing  of vessels 
13.1.  Radiographic  examination 
The radiographic  examination  of butt  welds  shall  be carried  out  in accordance  with  the 
requirements  of Annex  II under  the following  conditions: 
if 2 = 1 100  % radiographic  examination  of the welds  for all vessels  in the 
batch; 
if Z = 0 85 all  welds  made  by the same  technique  shall  be given  a radiographic 
examination  over  5 % of their  length. 
This examination  may  be performed  on one  or more  vessels  but on 
each  occasion  the  junctions  of the  main  welds  shall  be included. 
However  the  percentage  may  be reduced  to 2 % if at least  one 
vessel  is given  a 100 % examination  daily. 
if Z = 0 7 radiography  is not required. 
13.2.  Hydrostatic  test 
This  test  shall  be carried  out in accordance  with  the requirements  of 3.2 of Annex  II on 
every  vessel  in the batch. 
13.3.  Penetrant  fluid  weld  test 
This test  shall  be carried  out  in accordance  with  the requirements  of 2.4 in Annex  II on 
nozzle  and  penetration  welds  and  on ring/flat-end  fillet  welds  on one  vessel  in each 
batch. 
13.4.  EEC  pattern  verification  certificate  and mark 
If the results  of the inspection  are satisfactory,  the inspection  body  shall  issue  the EEC 
verification  certificate. 
The EEC  verification  certificate  shall  contain  the information  required  by section  3 of 
Annex  II to Council  Directive  76/767/EEC. 
C^A^^^ 
DA^AI^^A^ 
^ ^ar^s^^Cs^mb^ls  and  inscriptions 
Nothing  must  be stampe^onthewallofthepressureparts  of the vessel^hemarl^s  and 
inscriptions  stipulated  below  shall  be shown  on toadataplate^ 
A nonDdetachable  data  plate  shall  he placed  on each  vessel  in a position  that  is visible 
when  the vessel  is installedD 
pattern  approval  mar^s 
Notwithstanding  the requirements  in section  3 of Annex  I to Council  Directive 
the manufacturer  shall  affix  the ^C  pattern  approval  margin  the following  orders 
^ for  the vessel  referred  to in Article^^a^  of the Directives 
— the  st^li^ed  letters 
— the  number  ^denoting  this  Directives 
— the  capital  letters  identifying  the^tate  which  hasgranted^Cpatternapproval 
and the last two  digits  of the ^ear  in which  approval  was  granted^ 
— the  ^C  pattern  approval  numbers 
— examples 
^ for  the vessels  referred  to in Article^^of  the  Directives 
— thest^li^edletter^surroundedb^ahexagon^ 
— the  number^^denoting  this  Directives 
— the  capital  letters  identifying  the ^tate  which  has  granted  pattern  approval 
and the last two  digits  of the ^ear  in which  approval  was  granted^ 
— the  pattern  approval  numbers 
— examples 
^^verification  marl^s 
Notwithstanding  therequirements  of section^of  Annex  IltoCouncilDirective^^B^^B^B 
the inspection  bod^  shall  affix  the verification  margin  the following  orders 
— the  small  letters 
— the  capital  letters  identifying  the  ^tate  in which  the  verification  is carried  out 
together^  where  necessary  with  one  or two  numbers  identifying  a territorial 
subdivisions 
— the  marl^  of the inspection  bod^  affixed  b^ the verifying  agent^togetherwiththemarl^ 
of the verifying  agent  if appropriated 
— asurrounding  hexagons 
— the  verification  date^ear^  months  da^ 
— example^e^I^^ 
Inscriptions 
— the  value  of the test pressure  on the form^^^  ^^bar^ 
— the  value  of the design  pressure  in the form^^  ^^bar^ 
10. 2. 79 Official  Journal  of the  European  Communities No C 37/15 
— the  design  temperature  in the form:  T = . . . °C, 
— the  minimum  working  temperature  in the form:  Tmin  = . . . °C, 
— the  extra  corrosion  allowance  in the form:  S = . . . mm, 
— the  volume  of the  vessel  in the form:  V = ...  1, 
— the  name  or mark  of the  manufacturer  or person  responsible  for  placing  the  vessel  on 
the market, 
— the  manufacturer's  serial  number. 
A specimen  diagram  of the  marks  and  inscriptions  is given  below. 
£ 4 F 84 53 eF 1248 (2)  84/12/11 
Ph = 15  bar P = 10 bar 
T =  200  °C Tmin  = y 
o 
1 
S =  1 mm V = 2 0001 
Name/mark: 
No: SC  7592  B 
CALCULATION  OF PRESSURE  PARTS  AND  DIMENSIONING  OF APERTURES 
I.I. Calculation  of cylindrical  shell  rings 
The minimum  thickness  for pressure  resistance  is calculated  by the following  formula: 
PD; 
\ 20fZ  —P 
1.2. Calculation  of dished  ends 
Figure  1.1 
Hemispherical  end-plates 
0 003  D0  =£ e 0-16  D0 
Figure  1.2 
Elliptical  end-plates 
Simultaneous  limitations 
0 003  D0s=es=  0 08 D0 
H ^ 018  D0 
No C 37/16  Official  Journal  of the  European  Communities  10.2.79 
Figure  1.3 
Torispherical  end-plates 
Simultaneous  limitations: 
0 003  D„eSes:0  08 D» 
r >01Do 
R, =£ D„ 
H 2s 0-18  D() 
r 2  e 
The minimum  thickness  of these  dished  ends  is calculated  by the following  formula: 
PD„  r 
e=wc 
In addition,  the  thickness  of a torispherical  end-plate  must  not  be less  than: 
e = PR 
20 f- 0-5  P 
The shape  factor  C to be used  for  solid  ends  is given  in Table  1.1.  Figure  1.4 contains  a 
graphical  representation  of the  values  of C as a function  of H/D  for  different  values 
of P/10  f. 
With  the  exception  of hemispherical  end-plates,  all ends  of a thickness  less  than  the 
thickness  of the  shell  ring  shall  be provided  with  a cylindrical  edge  of a length  not 
exceeding  three  times  its thickness  or 50 mm. 
10.2.79 Official Journal  of the  European  Communities No C 37/17 
Shape  factor  C for dished  heads 
02 0  3 0-6  0  5 
Figure  1.4 
No C 37/18 Official  Journal  of the  European  Communities 10. 2. 79 
TABLE  1.1 
P/lOf  -0-001 P/lOf  = 0-0012 P/lOf  = 0-0015 P/lOf  -0-002 
H/D0 c/Do c e/Do c e/Do c e/Do C 
0-180 0-00211 2-81 0-00255 2-55 
0-200 0-00218 2-18 
P/10  f = 0-003 P/lOf  = 0-004 P/lOf  = 0-005 P/lOf  = 0-01 
H/D0 e/D0 c e/Do c e/Do c e/Do c 
0-180 0-00340 2-27 0-00423 2-12 0-00500 2-00 0-0088 1-76 
0-190 0-00316 2 11 0-00395 1 98 
0-200 0-00290 193 0-00364 1 82 0-00433 173 0-0077 154 
0-210 0-00273 1-82 0-00342 1-71 
0-220 0-00256 1-71 0-00320 1 60 0-00382 1 53 0-0068 138 
0-230 0-00236 1-57 0-00295 148 
0-240 0-00220 147 0-00276 138 0-250 0-00307 123 0-0055 1-10 
0-300 0-00220 0 88 0-00395 0-79 
0-350 0-00325 0-65 
0-400 0-0030 0-60 
0-450 0-0028 0-56 
0-500 0-0027 0-54 
P/lOf  = 0-02 P/lOf  = 0-05 P/lOf  = 0-1 P/lOf  = 0-2 
H/Do e/Do C e/Do C e/Do c e/Dg C 
0-180 0-0160 1-60 0 0366 146 0-0730 146 0-147 1 47 
0-200 0-0141 1 41 0-0330 132 0-0650 1-30 0-130 1-30 
0-220 0-0125 125 0-0292 1-17 0-0585 117 0-118 118 
0-250 0-0102 102 0-0250 1-00 0-0500 1-00 0-101 101 
0-300 0-0077 077 0-0193 0-77 0-0385 077 0-077 0-77 
0-350 . 0-0065 065 0-0162 065 0-0325 0-65 0-065 0 65 
0-400 0-0059 0 59 0-0149 0-60 0-0295 0-59 0-059 0 59 
0-450 0-0056 0 56 0-0140 0 56 0-0280 0 56 0-056 0 56 
0-500 0-0054 0-54 0-0136 0-54 0-0270 0-54 0-054 0-54 
P/lOf  = 0-5 
H/D0 e/Do C 
0-350 0-163 065 
0-400 0-150 0-60 
0-450 0-140 056 
0-500 0-136 0-54 
10.2.79 Official  Journal  of the  European  Communities No C 37/19 
1.3. Calculation  of flat end-plates 
The minimum  thickness  of an unreinforced  flat  end-plate  without  aperture  is 
calculated  by the following  formula: 
ef=QD ,v p 
10 f 
in which  Ct  is a shape  factor  which  must  have  the following  values: 
— Cj = 0 45 for the ends  represented  by Figures  1.5, 1.6 and 1.7, 
— Cj = 0*5  for the ends  represented  by Figure  1.8. 
Figure  1.5 
Cylindrical  body  sealed  by forging 
2 tf 
r 5= 0-25  ef 
r 2= 5 mm Figure  1.6 
End machined  from  a forged  blank 
r 3= 1-5 ef 
Figure  1.7 
Deep-drawn  flat end-plate 
0-25 ef s£ r s£ 2 ef 
r 3= 5 mm 
\ 
No C 37/20 Official  Journal  of the  European  Communities 10. 2, 79 
Unbraced  flat  end-plates 
\ 
& . . 7 
h Conventional  butt  weld 
r « 0-2 "to 0-5 t 
/)» *3 PD,/2t 
Figure  1.8 
10. 2. 79 Official  Journal  of the  European  Communities No C 37/21 
1.4. Dimensioning  of apertures  in a cylindrical  or spherical  part. 
The diameter  of the  apertures  shall  not  exceed  0"3  times  the  average  diameter  of the 
cylindrical  part. 
The thickness  eG  of the wall  in the vicinity  of an aperture  must  not be less  than: 
PD; 
C° 20  fZQ  — P 
The different  types  of stiffening  that  can  be used  are shown  in Figures  1.9 to 1.13. 
Figure  1.9 
Type  I: general  increase  in wall  thickness 
Figure  1.10 
Type  II: by a stiffening  ring 
Figure  1.11 
Type  III:  by a welded  nozzle 
The following  three  cases  are possible: 
0d. t)d, 
en 
yo 
Protruding Set-in Set-on 
No C 37/22  Official  Journal  of the  European  Communities  10.2.79 
Figure  1.12 
Type  IV: by an extruded  nozzle 
Figure  1.13 
Type  V: by a welded  nozzle  and  a stiffening  ring 
Set-in Protruding 
The weakening  factor  ZQ  is given  in Figure  1.14  for cylindrical  parts  and  Figure  1.15 
for spherical  parts  as a function  of the ratio: 
° and  for different  values  of — 
V ( D; + eD) eQ e« 
taking  account  of the following  restrictions: 
— For  type  I: the lowest  curves  are applicable 
10,2.79 Official  Journal  of the  European  Communities No C 37/23 
Factor  Z„ for cylindrical  shell  rings 
V (D, + e0) e< 
Figure  1.14 
No C 37/24 Official  Journal  of the  European  Communities 10. 2. 79 
Factor  Z„ for spherical  parts 
d, 
V (Dj + eQ) e0 
Figure  1.15 
10. 2. 79 Official  Journal  of the  European  Communities No C 37/25 
— For  type  II: 
the lowest  curves  are applicable 
(— = o\ and  : 3e0  b  = V (Dj  + eQ) e(l 
ep e 
the width  b may  be reduced  to bj provided  that  the thickness  of the stiffening  ring 
ep is increased  to epl  in accordance  with 
b| epi ^ b ep with  b, 3= 3e0  and  epi «£ e 
— For  type  III: 
~^2  and  1„ = V d„ • en 
the height  ln  may  be reduced  to ln, provided  that  the  branch  thickness  en  is 
increased  to en| in accordance  with: 
Li' eni ^ 1„ - en with  ^ ^ 2 
for a protruding  branch,  the  thickness  of the  branch  en  may  be reduced  by 20 % 
provided  that  the protrusion  m is not less  than  en. 
— For  type  IV: 
the length  1„  = V dG  • e„ 
— For  type  V: 
the restrictions  listed  for types  II and  II are applicable. 
1.5. Access  and  inspection  apertures 
1.5.1.  All  vessels  must  be provided  with  manholes  and/or  inspection  apertures  located  so that 
the vessel  may  be examined  visually. 
The minimum  number  and  type  of apertures  in the  cylindrical  part  of a vessel  are 
given  in Table  1.2. 
TABLE  1.2 
Number  and  type  of apertures 
Inside  diameter 
(D;) Length  of 
cylindrical  section 
(L) Minimum  number 
Inside  diameter 
(D;) Length  of 
cylindrical  section 
(L) Small  sight 
hole Large  sight 
hole Hand  hole Head  hole Man  hole 
0 < D; < 300 2 
notes 
1 and  2 0 0 0 0 
300 < Dj < 450 0 2 
notes 
1 and  2 0 0 0 
450 <D{  < 800 0 L < 1 500 0 2 o 
note  2 r 1 
note  3 0 0 450 <D{  < 800 
1 500  L « 2 000 0 0 2 or 1 
note  3 | note  3 0 450 <D{  < 800 
L > 2 000 0 0 note  4 0 
800 < Dj < 1 500 0 L < 2 000 0 0 
note  3 1 
note  3 0 
800 < Dj < 1 500 
L > 2 000 0 0 note  4 0 
D; > 1 500 0 0 0 0 1 
No C 37/26 Official  Journal  of the  European  Communities 10. 2. 79 
Note  1: where  the length  exceeds  1 500 mm,  additional  sight  holes  must  be provided. 
Note  2: the  sight  holes  must  be located  near  the ends  (providing  a view  of the longitudinal  weld). 
Note  3: a single  head  hole  and  a single  hand  hole  which  must  be situated  in the central  third  of the 
vessel  length. 
Note  4: the  number  of inspection  holes  must  be increased  accordingly.  For  a length  of less  than 
3 000  mm,  however,  it is sufficient  to site  a head  hole  in the  centre  of the  cylindrical 
section.  On  the  cylindrical  section,  the  distance  between  two  head  holes  must  not  exceed 
3 000  mm  and  the  distance  between  two  hand  holes  2 000  mm.  The  latter  must  each  be 
situated  near  an end. 
1.5.2.  Dimensions  of apertures 
1.5.2.1.  Sight  holes  are  apertures  with  an inside  diameter  of at least  30 mm  (small  sight  holes) 
or 50 mm  (large  sight  holes).  The  flange  height  must  not  exceed  the  diameter  of the 
aperture. 
1.5.2.2.  Hand  holes  are apertures  through  which  the  hand  and  a lamp  can  be inserted.  A hand 
hole  must  have  an elliptical  opening  of at least  80 x 100  mm  or an inside  diameter  of 
100 mm. 
The flange  height  must  not  exceed  65 mm  or, if conical  in shape,  100  mm.  If only  one 
hand  hole  is provided,  it must  not  be less  than  100  x 120  mm  or 120  mm  inside 
diameter. 
1.5.2.3.  Head  holes  are  apertures  through  which  the  head,  an arm  and  a lamp  can  be 
introduced  simultaneously.  Their  dimensions  must  be at least  220  x 320  mm  or 
320 mm  inside  diameter;  the flange  height  must  not  exceed  100  mm. 
1.5.2.4.  Man  holes  are  apertures  which  a person  not  carrying  any  auxiliary  equipment  can 
enter  and  leave  the vessel.  They  must  not  be less  than  300  x 400  mm  inside  diameter. 
The flange  height  must  not  exceed  150  mm  or, if conical  in shape,  170  mm. 
1.5.3.  Remarks 
1.5.3.1.  If  for  design  reasons  the  maximum  flange  height  given  above  has  been  exceeded,  the 
openings  must  be enlarged  accordingly  so as to give  the  same  facilities  for  internal 
inspection  of the vessel. 
1.5.3.2.  The  conditions  set out  in the tables  are applicable  subject  to the provisions  of section  1 
of the Annex. 
1.6. Flanges 
Flanges  must  comply  with  a national  standard  and  may  be used  only  for  the pressure 
specified  in that  standard. 
10.2.79 Official  Journal  of the  European  Communities No C 37/27 
ANNEX  II 
DESCRIPTION  OF TESTS 
II. 1. Mechanical  tests 
II. 1.1. The  following  tests  shall  be performed  in accordance  with  the Euronorms  specified: 
— Tensile  test 
Euronorm  No 2-57  for e > 3 mm, 
11-55  for e < 3 mm. 
— Bend  test 
Euronorm  No 6-55  for e > 3 mm, 
12-55  for e < 3 mm. 
— Impact  test 
Euronorm  No 45-63. 
— Hardness  test 
Euronorm  No 3-55. 
II. 1.2. Acceptance  criteria 
II. 1.2.1.  Tensile  test in welds  and parent  materials 
The breaking  load  obtained  must  be at least  equal  to the  minimum  breaking  load 
specified  for the plate. 
II. 1.2.2.  Bend  test on welds 
Each  test  piece  is placed  on supporting  roller  so that  the mandrel  axis  is in the centre 
of the weld;  the test  piece  must  pass  between  the supports  under  the action  of the 
mandrel.  The  diameter  of the mandrel  and  the space  between  the supporting  rollers 
shall  be determined  as follows  depending  on the thickness  of the test piece  'e': 
Table  for bend  tests 
Minimum  breaking  load  specified Diameter  of Space  between  supporting  rollers 
for the plate mandrel at the end  of test 
Less than  440 N/mm2 2 e 4-2 e 
From  440 to 500 N/mm2 3 e 5 2 e 
After  the test  the outside  surface  of the test  piece  shall  not exhibit  any  cracks  or other 
defects  of a length  exceeding  15 mm  measured  transversely  to the test  piece  or 3 mm 
measured  in the longitudinal  direction  of the test  piece.  A premature  rupture  at the 
corners  of the test piece  is not regarded  as a reason  for rejection. 
II. 1.2.3.  Impact  test on welds 
Three  test  pieces  are required.  The  impact  test are carried  out under  the conditions  set 
out in the third  indent  of 12.1  in the Technical  Annex. 
The results  are acceptable  if the mean  value  is not less  than  35 J/cm2  and  if at the 
same  time  the lowest  value  is not less than  25 J/cm2. 
No C 37/28 Official  Journal  of the  European  Communities 10. 2. 79 
II.1.2.4.  Hardness  test on welds 
The maximum  Vickers  hardness  of the weld  metal  and  the metal  in the heat-affected 
zone  may  not  exceed  that  of the  parent  metal  by more  than  80 and  100  units 
respectively. 
II.2. Non-destructive  examination 
II.2.1.  Radiographic  examination 
II. 2.1.1.  Preparation 
If need  be, scores  and  irregularities  on the two  faces  of the weld  may  be removed  or 
rectified  by an appropriate  mechanical  process  so that  the radiographic  image  of these 
irregularities  cannot  conceal  or be confused  with  the image  of a defect  to be detected. 
If so specified,  the reinforcement  on each  bead  must  be reduced  to 2 mm. 
II.2.1.2.  Procedure 
Welds  must  be radiographed  in accordance  with  ISO  specifications  R 1166  or R 1167 
using  classifications  B or C or the techniques  recommended  in ISO  2405. 
II.2.1.2.  Identification  of radiographs 
Reference  marks  must  be placed  along  the weld  so as to identify  each  radiograph 
according  to its location. 
Lead  characters  must  be placed  along  the weld  to give  the following  information  on 
each  radiograph: 
1. the area  of the weld  bead  convered  by the radiograph; 
2. the location  of the weld  bead  using  appropriate  letters  for the various  beads  with  a 
number  showing  whether  this bead  is the first,  second,  third,  etc.; 
3. a serial  number  denoting  the specific  vessel  to which  the radiograph  relates; 
4. marking  of weld  repairs  on the section  of the welded  connections  shown  in the 
radiograph. 
II.2.1.4.  Image  quality  indicator  (IQI) 
The image  quality  indicator  must  comply  with  the  requirements  of  ISO 
recommendation  R 1027  'Radiographic  image  quality  indicators  — principles  and 
identification'.  If a wire-type  indicator  is used,  the smallest  wire  diameter  visible  must 
not exceed  the values  given  below. 
If the step-and-hole  indicator  is used,  the diameter  of the smallest  visible  hole  must 
not exceed  the values  given  below. 
Thickness  of plate  in mm Wire-type  indicator Step-and-hole  indicator 
e < 6 0-10 025 
6 < e < 8 0 125 032 
8 < e < 10 0 16 0-40 
10 < e < 16 0-20 0-50 
II.2.1.5.  Examination  of radiographs 
Weld  radiographs  should  be examined  on the original  films  in accordance  with  the 
procedure  recommended  in ISO  standard  2504. 
10.2.79  Official  Journal  of the  European  Communities  No  C 37/29 
II.2.1.6.  Interpretation  of results 
The following  defects  are not acceptable: 
— any  cracks  or areas  showing  a lack  of fusion  at the weld  root, 
— any  elongated  inclusion  which  is greater  in length  than  the  thickness  'e' of the 
plate  and  at least  equal  in width  to the smaller  of the following  two  values:  2 mm 
or half  the thickness  'e', where  'e' is the thickness  of the materials  adjacent  to the 
weld.  If the weld  consists  of two  different  thicknesses,  the larger  is considered, 
— any  porosities  greater  than  those  shown  in the charts  in Figures  II. 1, II.2 and  II.3. 
Porosity  charts  for thicknesses  of less than  6 mm 
Assorted 
• •* • e # • • • 
Large 
¥ • # 
# 
Medium 
Fine 
I : :  '  5  :  ~ I. •  .  ' . 
Figure  II.l 
Porosity  charts  for thicknesses  of 6 to 13 mm 
Assorted 
Large 
Medium 
Figure  II. 2 
No C 37/30 Official  Journal  of the  European  Communities 10. 2. 79 
Porosity  charts  for thicknesses  exceeding  13 mm 
Assorted 
Large 
Medium 
Fine 
Figure  II.3 
11.2.3.  Macrographic  examination 
The macrographic  examination  of a complete  weld  cross-section  must  reveal  good 
penetration  and  an absence  of any  fusion  defects,  significant  inclusion  or other  defects. 
In cases  of doubt,  a micrographic  examination  of the  doubtful  zone  must  be carried 
out. 
11.2.4.  Penetrant  fluid  weld  test 
This  shall  be carried  out  in accordance  with  the  specifications  of ISO  document  DIS 
2694  Annex  J. 
11.2.5.  Ultrasonic  test 
11.2.5.1.  Techniques 
The examination  shall  be carried  out  in accordance  with  the  specifications  in ISO 
document  DIS  2694. 
11.2.5.2.  Unacceptable  weld  defects 
The limits  on linear  defects  specified  in the  first  two  indents  of II.2.1.6  may  be 
regarded  as valid  for tests  by magnetization  and  penetrant  fluid  tests.  When  the  inter-
pretation  of the  defects  reveals  cracks,  incomplete  fusion  or incomplete  penetration, 
these  defects  shall  be regarded  as unacceptable  whatever  their  length. 
10. 2. 79 Official  Journal  of the  European  Communities No C 37/31 
II.3. Overall  tests 
11.3.1.  Pressure  cycling  test 
For this  purpose,  a hydraulic  test  is performed  in cycles  in which  the  pressure  is 
repeatedly  built  up from  the initial  or residual  pressure  to the test pressure. 
The test  parameters  must  comply  with  one  of the  following  sets  of conditions,  the 
choice  being  left to the Member  State  concerned: 
1. — total  number  of cycles:  80  000, 
— test  pressure:  2/i  Ph 4- residual  pressure, 
— frequency:  15  cycles  per minute. 
2. — total  number  of cycles:  15  000, 
— test  pressure:  Ph  + residual  pressure, 
— frequency:  5  cycles  per minute. 
The residual  pressure  (i.e.  the pressure  remaining  after  the vessel  decompression  phase) 
must  not exceed  5 % of the test pressure. 
Throughout  the test,  the temperature  measured  on the outside  wall  of the vessel  must 
not exceed  50 °C. 
The test  is regarded  as satisfactory  if the vessel  completes  the specified  number  of 
cycles  without  leaking. 
11.3.2.  Hydrostatic  test 
Every  vessel  must  undergo  a hydrostatic  test  at a pressure  Ph which  must  not be less 
than the value  given  by the equation  set out below: 
RE is the guaranteed  minimum  yield  point  at the test temperature; 
Ret  is the yield  point  at the working  temperature; 
P is the working  pressure. 
However,  the pressure  P^ must  be such  that  it does  not create  in the vessel  a general 
membrane  stress  greater  than  90 % of the minimum  value  of RE. 
The test  pressure  must  be iield  at the specified  value  long  enough  to allow  all the 
surfaces  aqd  joints  to be examined  visually.  The  vessel  must  not  show  any  sign  of 
general  plastic  deformation  or leakage. 
Every  vessel  tested  which  fails  the hydrostatic  test must  be rejected. 
II.4. Destructive  testing 
II.4.1.  Hydraulic  pressure  bursting  test 
II.4.1.1.  Procedure 
The hydraulic  pressure  bursting  test  must  be performed  in two  successive  stages  using 
an installation  enabling  the pressure  to be built  up regularly  until  the vessel  bursts  and 
a graph  showing  the variation  of pressure  with  time  to be recorded. 
In the initial  stage,  the rate  of pressure  build-up  to the value  corresponding  to the 
onset  of plastic  deformation  must  be equal  to about  five  bar. 
No C 37/32 Official  Journal  of the  European  Communities 10. 2. 79 
With  the test,  it must  be possible  to determine: 
(a) the pressure  at which  plastic  deformation  commences; 
(b) the bursting  pressure; 
(c) local  and  overall  deformation  of the vessel. 
II.4.1.2.  Test  acceptance  criteria 
The measured  bursting  pressure  (Pr)  must  be higher  than  the  calculated  theoretical 
minimum  bursting  pressure  (Prt). 
This theoretical  pressure  is calculated  from  the  minimum  thickness  obtained  by 
applying  the formula  set out  in Annex  I and  from  the vessel's  calculated  minimum 
guaranteed  tensile  strength  (Rr)  according  to the formula: 
p 20'  R* 
" D  - e 
zlMVEX/// 
COUPON  PLATE 
Quality  control  is carried  out on one  or more  coupon  plates. 
To represent  the longitudinal  joint,  the coupon  plate  shall  consist  of an extension  piece  added  to 
the joint  in question  and  welded  at the same  time.  Furthermore  the parent  material  and  thickness 
of the coupon  plate  shall  be identical  with  those  of the shell  ring. 
No coupon  plate  need  be provided  for  circumferential  joints  if the  welding  procedure  and 
technique  are the same  for both  types  of joint. 
If the method  of welding  circumferential  joints  differs  from  that  used  for longitudinal  seams,  a 
separate  coupon  plate  must  be prepared  by the same  welding  procedure  as used  for the circum-
ferential  welds  on the vessel.  This  coupon  plate  shall  consist  of two  sections  of tube  of the same 
material,  thickness  and diameter  as for production,  welded  together  by a circumferential  weld. 
The dimensions  of the coupon  plate  shall  be such  that  a sufficient  number  of test  pieces  can  be 
taken  to carry  out the tests  specified  in section  12. 
ACCEPTANCE  OF THE  WELDING  PROCEDURE 
IV. 1. General 
By having  the welding  procedure  accepted,  the manufacturer  must  prove  that  he is 
capable  of welding  materials  to be used  for the construction  of the pressure  vessels  to 
be produced. 
For that  purpose  he shall  carry  out  test  welds  in accordance  with  the  following 
specifications. 
The test  welds  shall  consist  of the  execution  of butt  welds  and  fillet  welds.  These 
welds  must  be representative  of the production  welds  on all parts  subjected  to pressure 
in the vessels. 
1Q. 2. 79 Official  Journal  of the  European  Communities  No  C 37/33 
IV.2.  Execution  of the welds 
IV.2.1.  Parent  metal 
The plates  and  tubes  used  for the welding  procedure  acceptance  tests  shall  be of the 
same  grade  and  shall  conform  to the same  specifications  as the plates  and  tubes  used 
in actual  production.  However,  acceptance  for a given  grade  is also  valid  for grades 
having  a lower  impact  strength  and  less  favourable  chemical  composition. 
IV.2.2.  Filler  products 
The weld  filler  materials,  i.e.  electrodes  and  combinations  of wire,  powder  and 
shielding  gas,  must  be the same  for acceptance  of the welding  procedure  as for actual 
production. 
IV.2.3.  Type  of edge  preparation 
In manual  welding,  the type  of preparation  (single  or double  V, single  or double  U 
and straight  bevel)  may  be changed  in production  welding  without  necessitating  reac-
ceptance  of the welding  procedure. 
In the case  of semi-automatic  welding,  any  change  in the type  of edge  preparation 
requires  a fresh  acceptance  test. 
IV.2.4.  Welding  method 
The welding  method  and,  in the case  of semi-automatic  or automatic  welding,  the 
type of welding  equipment  must  be the same  for the acceptance  test  as for actual 
production. 
IV.2.5.  Validity  of the welding  procedure 
IV.2.5.1.  A  fresh  acceptance  test is required  if: 
(a) in arc  welding,  the  current  range  and  welding  speed  and,  in submerged  arc 
welding,  the range  of voltages  used  are appreciably  modified; 
(b) in the arc welding  of a simple  butt  joint,  the back  support  is added  or removed; 
(c) in the oxyacetylene  welding  of a simple  butt  joint,  a back  support  is added; 
(d) in the case  of machine  welding,  multi-pass  welding  on each  face  is replaced  by 
one-pass  welding  on each  face; 
(e) if the shielding  gas is changed  or not used. 
IV.2.5.2.  Longitudinal  and circumferential  joints 
If a test plate  is welded  to represent  longitudinal  joints,  there  is no need  for a test on 
the circumferential  joints  provided  that  the welding  method,  procedure  and  techniques 
are the same  for the two  types  of joint. 
If the method  of welding  circumferential  joints  differs  from  that  used  for longitudinal 
joints,  a test piece  consisting  of two  tubular  sections  assembled  by means  of a circum-
, ferential  weld  must  be produced  in accordance  with  the procedure  used  for the circum-
ferential  welds  on the vessel.  , 
IV.2.6.  Dimensions  of the test assembly 
The dimensions  of the test assembly  shall  be such  that  it is possible  to take  a sufficient 
number  of test pieces  to carry  out the tests  specified  in 2.7 of Annex  IV. 
No C 37/34 Official  Journal  of the  European  Communities 10.2.79 
IV.2.7.  Inspection  and  testing 
IV.2.7.1.  Butt  welds 
The tensile,  bend,  impact  and  hardness  tests  shall  be carried  out  in accordance  with 
the specifications  in II. 1.1 of Annex  II. 
The inspections  and  tests  to be carried  out are as follows: 
(a) a radiographic  examination 
the radiographic  examination  shall  be carried  out  on the  full  length  of the  welds 
and before  test  pieces  are taken; 
(b) one  tensile  test 
the tensile  test  piece  shall  be cut transversely  to the weld; 
(c) three  impact  tests  in the weld; 
(d) one  bend  test  on the underside  of the weld; 
(e) one  bend  test  on the upper  side  of the weld; 
(f) a macrographic  examination; 
(g) one  hardness  test. 
IV.2.7.2.  Fillet  welds 
The examinations  to be carried  out are as follows: 
(a) a visual  examination; 
(b) a macrographic  examination. 
IV.2.8.  Acceptance  criteria 
IV.2.8.1.  The  acceptance  criteria  for the tensile,  bend,  impact  and  hardness  tests  are specified  in 
II. 1.2 of Annex  II. 
IV.2.8.1.1.  The  radiographic  examination  shall  be carried  out  in accordance  with  II.2.1  of 
Annex  II: 
IV.2.8.1.2.  The  macrographic  examination  shall  be carried  out  in accordance  with  II.2.3  of 
Annex  II. 
QUALIFYING  TESTS  FOR  WELDERS  OR  OPERATORS 
The qualifying  tests  for  welders  or operators  shall  be carried  out  in exactly  the  same  way  and 
under  the same  conditions  as the welding  procedure  acceptance  tests. 
The requirements  for th^ qualifying  tests  for welders  or operators  are the same  as for the welding 
procedure  acceptance  tests. 
Welders  or operators  must  undergo  fresh  qualifying  tests  if the  welding  procedure  has  to be re-
accepted  as a result  of a change  in one  of the conditions  specified  in 2.5 of Annex  IV. 
Welders  or operators  must  qualify  if they  have  not  been  engaged  on the same  type  of work  in the 
construction  of pressure  vessels  during  the previous  six months. 
10. 2. 79 Official  Journal  of the  European  Communities No C 37/35 
ANNEX  VI 
EEC  PATTERN  APPROVAL  CERTIFICATE 
issued  pursuant  to Council  Directives  76/767/EEC  of 27 June  1976  and  ... of 
Pressure  vessels 
Approval  No: Date: 
Type  of vessel: 
Manufacturer  or agent: 
EEC  pattern  approval  mark: 
Validity: 
Any  further  information  may 
be obtained  from: 'Description  of the-vessel  or variant  approved' 
Capacity:  L:  thickness: 
Pmax:  D: 
'Name  and  address  of  the  manufacturer  or  his  authorized 
agent' 
Article  3(a)  £  4  F 8453 
Article  3 (b) (^)  4 F 8453 
5 years/10  years 
Name  and  address  of the  inspection  authority 
Done  at (date) 
(Signature)