13. 9. 74 Official  Journal  of the European  Communities No C 104/59 
Proposal  for a Council  Directive  on the approximation  of the laws  of the Member  States 
relating  to welded  unalloyed  steel  gas cylinders 
(Submitted  to the Council  by the Commission  on  18 July  1974) 
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 the  Member  States  the  construction  and 
controls  of gas  cylinders  are  subject  to mandatory 
provisions  varying  from  one  Member  State  to 
another,  and  consequently  hinder  trade  in such 
vessels;  that  it is therefore  necessary  to undertake  the 
approximation  of these  provisions; 
Whereas  the  Council  Directive  of ,  on the 
approximation  of the  laws  of the  Member  States 
relating  to common  provisions  on pressure  vessels 
and to  the  methods  used  for  verifying  these 
apparatus,  lays  down  in particular  the procedures  of 
EEC  approval  and  inspection  for  these  vessels; 
whereas  according  to this  Directive,  it is advisable  to 
lay down  the  technical  requirements  to be complied 
with  by  EEC-type  welded  unalloyed  steel  gas 
cylinders  with  a capacity  of 0-2  to 150  litres  in order 
to be put into  circulation,  marketed  and  used  without 
restraint  after  having  undergone  inspection  and 
bearing  accordingly  the marks  and  the symbols, 
HAS  ADOPTED  THIS  DIRECTIVE: 
Article  1 
This  Directive  applies  to  the  unalloyed  steel 
stress-resistant  shells  of welded  gas  cylinders,  i.e., 
formed  from  several  pieces  likely  to be refilled  several 
times,  with  a capacity  ranging  from  0-2 to 150  litres 
inclusive  designed  to contain  compressed,  liquified  or 
dissolved  gases  except  liquified  gases  at very  low 
temperatures  and  acetylene.  The  design  pressure  for 
these  cylinders  shall  not exceed  60 bars. 
These  welded  gas  cylinders  are  hereinafter  called 
'cylinders'. Article  2 
The cylinders  which  conform  to the requirements  set 
out in  Annex  to  this  Directive  are  EEC-type 
cylinders. 
Article  3 
No Member  State  may,  for  reasons  connected  with 
construction  or verification,  prohibit  or restrain  the 
placing  on the  market  and  putting  into  appropriate 
service  of EEC-type  cylinders  bearing  the  EEC 
approval  symbol  and  the  EEC  inspection  mark, 
subject  to the conditions  provided  for in Article  4. 
Article  4 
An EEC-type  cylinder  shall  be subject  to: 
(a) EEC  approval: 
1. if its capacity  is not  more  than  one  litre, 
irrespective  of the hydraulic  test  pressure; 
2. if its capacity  is more  than  one  litre  but  not 
more  than  five  litres  and  provided  the 
hydraulic  test  pressure  is 15 bars  or less. 
(b) EEC  approval  and  EEC  inspection: 
1. if its capacity  is more  than  one  litre  but  not 
more  then  five  litres  and  provided  the 
hydraulic  test  pressure  is more  than  15 bars; 
2. if its  capacity  is more  than  five  litres 
irrespective  of the hydraulic  test  pressure. 
Article  5 
1. Member  States  shall  put  into  force  the  laws 
regulations  and  administrative  provisions  necessary 
to comply  with  this  Directive  within  18 months  of its 
notification  and  shall  forthwith  inform  the 
Commission  thereof. 
2. Member  States  shall  ensure  that  the texts  of the 
provisions  of national  law  adopted  by them  in the 
field  governed  by this  Directive  are communicated  to 
the Commission. 
Article  6 
This  Directive  is addressed  to the Member  States. 
No C 104/60 Official  Journal  of the  European  Communities 13. 9. 74 
ANNEX  I 
1. SYMBOLS  AND  TERMS,  USED  IN THIS  ANNEX 
1.1. The  symbols  used  in this  Annex  have  the following  meanings: 
Ph = hydraulic  test  relative  pressure  (design  pressure)  in bars; 
Pr =  cylinder  bursting  relative  pressure  measured  in the bursting  test,  in bars; 
Prt = calculated  minimum  theoretical  rupture  relative  pressure,  in bars; 
Re = minimum  value  of the yield  stress  (Reh  or Rp  0-2)  guaranteed  by the cylinder 
manufacturer,  in N/mm2; 
Rra  = minimum  value  of the tensile  strength  guaranteed  by the cylinder  manufacturer, 
in N/mm2; 
Rt = actual  tensile  strength,  in N/mm2; 
a =  minimum  thickness  of the cylindrical  shell  wall,  in mm; 
D =  nominal  outside  diameter  of the cylinder,  in mm; 
R =  inside  radius  of curvature  of convex  base; 
r =  inside  radius  of junction  of convex  base; 
H =  outside  height  of dished  ends; 
h =  height  of cylindrical  part  of dished  ends; 
L =  length  of cylinder  stress-resistant  shell; 
A =  elongation  value  (%)  of parent  metal; 
Vo = initial  volume  of the cylinder  at the start  of the bursting  pressure  test; 
V =  final  volume  of the cylinder  on bursting. 
1.2. Yield  Stress 
The term  'yield  stress'  means  the upper  yield  stress  (Reh)-
For steels  that  do not  exhibit  a defined  elastic  limit,  however,  the value  to be used  is 
the conventional  yield  stress  Rp  0-2  i.e.,  the value  of the stress  (a) which  gives  rise  to 
a non-proportional  elongation  equal  to 0-2%  of the gauge  length  of the test-piece. 
1.3. Normalization 
The term  'normalization'  relates  to the heat  treatment  to which  a completed  cylinder  is 
subjected,  during  which  the cylinder  is heated  to a uniform  temperature  higher  than 
the steel's  highest  critical  point  (Acs)  and  then  cooled  in still  air. 
1.4. Stress  relieving 
The term  'stress  relieving'  relates  to the heat  treatment  to which  a completed  cylinder 
is subjected,  during  which  the cylinder  is heated  to a" temperature  below  the steel's 
lowest  critical  point  (AC1)  in order  to reduce  the residual  stresses. 
2. TECHNICAL  REQUIREMENTS 
2.1. Materials 
2.1.1.  The  material  used  for the manufacture  of the cylinder  stress-resistant  shells  shall  be 
steel  as specified  by EURONORM  120-72. 
13. 9. 74 Official  Journal  of the  European  Communities No C 104/61 
2.1.2. 
2.1.3. 
2.1.4. 
2.1.5. 
2.1.6. 
2.2. 
2.3 v 
2.3.1. 
2.3.2. 
2.3.3. 
2.3.4. 
2.4. 
2.4.1. 
2.4.1.1 
2.4.1.2. 
2.4.1.3. 
2.4.1.4. All components  of the cylinder  body  and  the parts  welded  thereto  shall  be made  of 
mutually  compatible  materials. 
The filler  materials  shall  be compatible  with  the  steel  so as to form  welds  with 
properties  equivalent  to those  specified  for the parent  metal. 
The cylinder  manufacturer  shall  obtain  and  provide  cast  analysis  certificates  in respect 
of the steels  supplied  for the manufacture  of the cylinder  stress-resistant  shells. 
The inspection  authority  shall  have  the opportunity  of making  independent  analyses. 
These  analyses  shall  be carried  out either  on specimens  taken  from  the materials  as 
supplied  to the cylinder  manufacturer  or on the finished  cylinders. 
The manufacturer  shall  make  available  to the  inspection  authority  the  results  of 
metallurgical  and  mechanical  tests  and  analyses  carried  out on welds  and  shall  also 
describe  the welding  methods  and  processes  adopted  which  can  be regarded  as repre-
sentative  of the welds  made  during  production. 
Heat  treatment 
When  heat  treatment  has been  applied,  the manufacturer  shall  state  the type  of treatment 
employed  (normalization  or stress-relieving),  the temperature  and  duration  thereof  and 
the quenching  technique  used. 
Calculation  of the parts  under  pressure 
The wall  thickness  at any  point  on the stress-resistant  shell  shall  not be less than  that 
calculated  by the formula: 
Ph • D 
20 Re  +Ph 
1-3 
The value  of Re  shown  in the formula  shall  in no case  be greater  than  0-75  Rm. 
The minimum  wall  thickness  shall  in no case  be less than: 
— 1-5  mm for cylinders  with  a capacity  of less  than  6-5 litres; 
— 1-9  mm for cylinders  with  a capacity  equal  to or more  than  6-5 litres  but less  than 
30 litres  and  whenever  the ratio  L/D  < 2; 
— whichever  of 1-9 mm or 0-136  ]^D  is the higher  for cylinders  with  a capacity  equal 
to or more  than  6-5 litres  but less  than  30 litres,  when  the ratio  L/D  ^ 2, and  for 
cylinders  with  a capacity  of 30 litres  or more. 
The dimensions  of the dished  ends  of cylinders  shall  fulfil  the following  conditions: 
if torispherical:  R < D r ^ 0-10  D h  > 4a H  > 0-25  D; 
if ellipsoidal:  H  ^ 0-25  D h  ^ 4a. 
The cylinder  body,  valve  excluded,  may  be up of two  or three  parts.  The  ends  shall  be 
in one  piece  and  convex. 
Construction  and  workmanship 
General  requirements 
The manufacturing  facilities  and  techniques  and  the inspection  methods  used  in pro-
duction  shall  be such  as to ensure  that  cylinders  conforming  to the provisions  of this 
Directive  are produced. 
Drawings  shall  contain  all important  particulars,  such  as dimensions,  materials,  openings 
and the locations  of markings  and  symbols. 
The manufacturer  shall  ensure  through  proper  supervision  over  the manufacture  that 
wall thicknesses  are at least  equal  to the dimensions  shown  on the drawing. 
The surfaces  of the plates  of the cylindrical  body  and  pressed  parts  shall  be clean 
and free  from  serious  defects. 
No C 104/62 Official  Journal  of the European  Communities 13. 9. 74 
2.4.2.  Welding  conditions 
2.4.2.1.  The  manufacturer  shall  have  at his disposal  staff  specializing  in welding  operations 
and supervision  and  in non-destructive  testing. 
2.4.2.2.  The  manufacturer  shall  be an expert  in the  techniques  used  in the  fabrication  and 
welding  processes.  He shall  notify  the Member  State  of any  amendment  or major 
extension  to his manufacturing  programme. 
2.4.3.  Welding  specifications 
2.4.3.1.  There  shall  be no butt  welds  in the stress-resistant  shell  in any  area  where  a change 
in profile  occurs. 
2.4.3.2.  There  shall  be no superimposition  of an angle  weld  over  a butt  weld  and  there  shall 
be a space  of at least  10 mm  between  them. 
2.4.3.3.  The  parts  that  make  up the  stress-resistant  shell  (ends,  rings  and  orifice  bases)  shall 
be welded  in accordance  with  Figs.  1, 2 and  3 of this  Annex,  viz.: 
— Longitudinal  weld  (Fig.  1), 
— Circumferential  weld  (Fig.  2), 
— Valve  sleeve  weld  (Fig.  3). 
The maximum  permissible  malalignment  of the  joint  faces  shall  be one-fifth  of the 
thickness  (l/5a). 
2.4.4.  Welding  of fittings 
2.4.4.1.  The  steel  footrings,  handles  and  protective  collars  shall  be assembled  by angle  welding, 
the contact  surfaces  with  the stress-resistant  shell  being  provided  by the cross-section 
of the item  to be assembled. 
The welding  shall  be along  the entire  length  of the seam  but  not  necessarily  on both 
sides. 
2.4.4.2.  Such  identification  plates  as are required,  shall  be welded  to the stress-resistant  shell 
over  their  entire  peripheries.  In order  to allow  air to be expelled  during  heat  treatment, 
each  identification  plate  shall  be provided  with  a hole  through  it which  is suitably 
plugged  once  the heat  treatment  is complete. 
2.4.5.  Welding  techniques  and  methods 
2.4.5.1.  Butt  welding  shall  be carried  out by an automatic  technique. 
2.4.5.2.  All  traces  of oil,  grease  and  rust  shall  be eliminated  from  the welding  edges  before 
welding. 
2.4.5.3.  Complete  penetration  of the weld  seam  shall  be obtained  over  the entire  thickness  and 
length  of the joints 
2.4.5.4.  The  techniques  and  methods  used  shall  be such  that  the welds  are seen  to be smooth 
and regular  and  free  from  incisions,  craters,  deviations  or undercuts. 
With  regard  to butt  welds,  any  barrelling  shall  not  be greater  in height  than  one-
quarter  of the width,  except  for the overlay  at the end  of the seam,  where  a reinforce-
ment,  which  shall  be entirely  devoid  of craters,  is permissible. 
Angle  welds  shall  be seen  to be regular  and  smooth  and  devoid  of craters  at the extre-
mities.  The  joint  made  between  welded  pieces  shall  be progressive  and  free  from 
incisions  and  undercuts. 
2.4.5.5.  Before  the ends  are squeezed,  a visual  examination  of the  longitudinal  weld  shall  be 
carried  out  on both  of its faces  in order  to ensure  that  the weld  shows  a continuous 
penetration  without  any  deviation  of the weld  seam. 
2.4.5.6.  All  the pressurized  parts  of the  cylinder  shall  be inspected  internally  at each  stage  in 
manufacture  and  inspected  externally  after  the final  assembly,  the purpose  of these 
inspections  being  to ascertain  that  the  cylinder  is free  from  any  surface  or welding 
defect  liable  to endanger  safety. 
13. 9. 74 Official  Journal  of the European  Communities No C 104/63 
2.4.6.  Cylindricity 
The out-of-roundness  of the cylindrical  part  shall  be limited  to such  a value  that  the 
difference  between  the maximum  and  minimum  outside  diameter  in the same  cross-
section  is not more  than  1%  of the average  of those  diameters. 
2.4.7.  Fittings 
2.4.7.1.  The  cylinder-carrying  handles  or rings  shall  be fabricated  and  welded  to the cylinder 
body  in such  a way  as not to cause  dangerous  concentrations  of stresses  or form  traps 
for water. 
2.4.7.2.  The  footring  must  be sufficiently  strong  and  made  of metal  compatible  with  that 
of the cylinder  and  give  the cylinder  sufficient  stability.  The  top  edge  of the footring 
must  fit the stress-resistant  shell  perpendicularly  and  be welded  to it in such  a way  as 
to prevent  the formation  of water  traps.  The  footring  must  contain  ventilation  holes. 
2.4.7.3.  Any  other  material,  however,  may  be used  for the manufacture  of the  footrings  and 
cylinder-carrying  handles  or rings,  provided  that  their  strength  is assured  and  that  all 
risk of the cylinder  end  corroding  is removed. 
2.4.8.  Protection  of the cock  or valve 
The cylinder  cock  or valve  shall  be effectively  protected,  either  through  the  way  in 
which  it is designed  or through  the design  of the cylinder  itself  (e.g.,  with  a protective 
collar),  or by means  of a protective  cap  or cover  secured  by a safe  device. 
3. TESTS 
3.1. Mechanical  tests 
3.1.1.  General  requirements 
3.1.1.1.  The  mechanical  tests,  where  not covered  by the requirements  contained  in this  Annex, 
shall  be carried  out in accordance  with  the EURONORM  Nos: 
(a) 2-57  and  11-55  for the tensile  test,  where  a 3  mm  and  a < 3 mm  respectively; 
(b) 6-55  and  12-55  for the  bend  test,  where  a ^ 3 mm  and  a < 3 mm  respectively. 
3.1.1.2.  All  the mechanical  tests  for checking  the  properties  of the  parent  metal  and  filler 
material  used  for  the  stress-resistant  shells  of the  gas  cylinders  shall  be carried  out 
on test  pieces  taken  from  the finished  cylinders. 
3.1.2.  Types  of test  and  evaluation  of test  results 
3.1.2.1.  Each  sample  cylinder  shall  be subjected  to the following  tests: 
A. For  cylinders  containing  only  circumferential  welds  (two  pieces),  on test  pieces  taken 
from  the places  shown  in Fig.  1 of this  Annex: 
1 tensile  test:  parent  metal  in the longitudinal  direction  (a), 
1 tensile  test:  perpendicular  to the circumferential  weld  (b), 
1 bend  test:  top  of circumferential  weld  (c), 
1 bend  test:  bottom  of circumferential  weld  (d); 
B. For  cylinders  with  longitudinal  and  circumferential  welds  (three  pieces),  on test 
pieces  taken  from  the places  shown  in Fig.  5 of this  Annex: 
1 tensile  test:  parent  metal  of the cylindrical  part  (a), 
1 tensile  test:  parent  metal  from  bottom  (b), 
1 tensile  test:  perpendicular  to the longitudinal  weld  (c), 
1 tensile  test:  perpendicular  to the circumferential  weld  (d), 
No C 104/64 Official  Journal  of the  European  Communities 13. 9. 74 
1 bend  test:  top  of longitudinal  weld  (e), 
1 bend  test:  bottom  of longitudinal  weld  (f), 
1 bend  test:  top  of circumferential  weld  (g), 
1 bend  test:  bottom  of circumferential  weld  (h). 
3.1.2.1.1.  Test  pieces  which  are not sufficiently  flat must  be flattened  by cold  pressing. 
3.1.2.1.2.  In all test  pieces  containing  a weld,  the weld  is machined  until  it is flush  with  the 
surface  of the plate. 
3.1.2.1.3.  Any  cut across  the weld  in a test piece  must  be sound  and  compact  throughout. 
3.1.2.2.  Tensile  test 
3.1.2.2.1.  The  procedure  for carrying  out the tensile  test  shall  be as given  in the appropriate 
EURONORM  in compliance  with  subsection  3.1.1.1. 
The two  faces  of the test  piece  which  are respectively  the inside  and  outside  walls 
of the cylinder  shall  not be machined. 
3.1.2.2.2.  The  elongation  of the parent  metal  (in percent)  shall  not be less than: 
A = 1 000  ~ Rt 
c 
The values  of coefficient  c are respectively  25 and 20 for wall  thicknesses  of less  than 
3 mm  and  3 mm  or above. 
In no case  must  the elongation  in percent  be less  than  that  given  in the following 
table: 
Rt < 500 N/mm» Rt > 500 N/mm! 
3 mm  a  ^ 5 mm 27 19 
a < 3 mm 22 15 
3.1.2.2.3.  The  'perpendicular  to the weld'  tensile  test shall  be carried  out on a test piece  having  a 
thinned  cross-section  25 mm  in width  and  15 mm  in length  measured  from  either 
edge  of the weld,  as shown  in Fig.  6 of this  Annex.  Beyond  this  central  part  the 
width  of the test specimen  must  increase  progressively. 
3.1.2.2.4.  The  observed  values  of the elastic  limit  and  the tensile  strength  should  be at least 
equal  to those  guaranteed  for the parent  metal  irrespective  of where  the rupture  is 
produced  in the cross-section  of the central  part  of the test piece. 
3.1.2.3.  Bend  test 
3.1.2.3.1.  The  procedure  for carrying  out the bend  test  shall  be as given  in the appropriate 
EURONORM  in compliance  with  subsection  3.1.1.1. 
3.1.2.3.2.  The  test piece  shall  remain  uncracked  when  bent  inwards  around  a former  until  the 
interior  edges  are at a distance  apart  not greater  than  the diameter  of the former. 
3.1.2.3.3.  The  ratio  (n) between  the diameter  of the former  and  the thickness  of the test  piece 
shall  conform  to the values  given  in the following  table: 
Actual  tensile  strength 
Rt N/mm2 Value  of n 
up to 440 inclusive 2 
above  440 to 520 inclusive 3 
above  520 4 
13. 9.74 Official  Journal  of the  European  Communities No C 104/65 
3.2. Bursting  test under  hydraulic  pressure 
3.2.1.  Test  conditions 
3.2.1.1.  The  bursting  test  under  hydraulic  pressure  shall  be carried  out  in two  successive 
stages  by means  of an apparatus  such  that  the pressure  in the cylinder  increases 
regularly  until  the cylinder  bursts  and  that  the curve  of the pressure  variation  with 
time is recorded. 
3.2.1.2.  During  the Stage  1, the rate  of pressure  increase  until  the point  at which  plastic 
deformation  begins  shall  be about  1 bar/s. 
As from  that  pressure  value  (Stage  2), the rate  of pumping  shall  be increased  to twice 
what  it was  in Stage  1 and kept  at a steady  value  until  the cylinder  bursts. 
3.2.2.  Performance  of test 
The bursting  test under  hydraulic  pressure  shall  afford: 
(a) an examination  of the pressure/time  curve  telling  the pressure  at which  plastic 
deformation  of the cylinder  commences,  the bursting  pressure  and the deformation 
of the cylinder  during  the test, 
(b) a measurement  of the volume  of water  used  between  the time  when  the pressure 
starts  to rise  and  the time  of bursting,  giving  the volumetric  expansion  of the 
cylinder, 
(c) an examination  of the fracture  and the shape  of its edges. 
3.2.3.  Test  acceptance  conditions 
3.2.3.1.  The  pressure  observed  at the initiation  of the plastic  deformation  shall  be not less than 
four-thirds  of the hydraulic  test pressure. 
3.2.3.2.  The  measured  bursting  pressure  (Pr)  shall  be greater  than  the calculated  minimum 
theoretical  bursting  pressure  (Prt). 
This theoretical  pressure  shall  be calculated  from  the minimum  effective  thickness  'a' 
and the guaranteed  minimum  tensile  strength  (Rm)  used  for the cylinder  calculation, 
according  to the formula: 
p, 20  a Rm 
P" " "d^T 
The measured  bursting  pressure  (Pr)  shall  not be less  than  nine-fourths  of the test 
pressure  (Ph). 
3.2.3.3.  The  specific  change  in volume  of the cylinder  (/  at  the time  of bursting  shall 
not be less than  20 %. A  °  ' 
3.2.3.4.  The  bursting  test shall  not cause  any fragmentation  of the cylinder. 
3.2.3.5.  The  main  fracture  shall  not be of the brittle  type,  i.e.,  the edges  of the fracture  shall 
not be radial  but shall  be sloped  in relation  to a diametrical  plane  and  shall  display 
a striction  throughout  their  thickness. 
3.2.3.6.  The  fracture  shall  not reveal  a characterized  defect  in the metal. 
3.2.3.7.  In  the case  of a three-piece  cylinder  the burst  shall  not originate  in one  of the ends, 
a longitudinal  weld  or a circumferential  weld  (unless  the burst  is perpendicular 
thereto).  The  last requirement  also  applies  to a two-piece  cylinder. 
3.3. Hydraulic  test 
3.3.1.  The  hydraulic  test pressure  shall  equal  the design  pressure  (Ph). 
3.3.2.  The  water  pressure  in the cylinder  shall  increase  regularly  until  the test  pressure  is 
reached. 
No C 104/66 Official  Journal  of the  European  Communities 13. 9. 74 
3.3.3.  The  cylinder  shall  remain  under  the test  pressure  for a sufficient  length  of time  to 
demonstrate  that  the  pressure  shows  no tendency  to fall  and  that  leaktightness  has 
been  achieved. 
3.3.4.  Any  cylinder  which  does  not satisfy  these  test  requirements  shall  be rejected. 
4. EEC  APPROVAL 
4.1. The  applicant  for approval  shall  submit  the documentation  necessary  for the inspection 
prescribed  below,  together  with  three  prototype  cylinders  which  are entirely  represen-
tative  of future  output  and  any  additional  information  required  by the  Member 
State. 
4.2. In  the course  of the EEC  approval  process,  the Member  State  shall: 
— verify  that  the calculations  set out in section  2.3 are correct; 
— verify  that  the provisions  set out in sections  2.1,  2.2 and  2.4 have  been  fulfilled; 
— perform  on the cylinders  submitted  as prototype: 
(a) the  test  set forth  in section  3.1 on one  cylinder, 
(b) the test  set forth  in section  3.2 on another  cylinder. 
—- issue  in the  EEC  approval  certificate  conforming  to the  model  provided  for  in 
Annex  II to this  Directive. 
5. EEC  INSPECTION 
5.1. For  the purpose  of the EEC  inspection  the cylinder  manufacturer  shall  make  available 
to the inspection  authority: 
5.1.1.  the  EEC  approval  certificate; 
5.1.2.  the  cast  analysis  certificates  in respect  of the steels  supplied  for the construction  of the 
stress-resistant  shells  of the cylinders; 
5.1.3.  the  means  of identifying  the cast  of steel  used  for each  cylinder; 
5.1.4.  the  documents  relating  to the heat  treatment  provided  in section  2.2; 
5.1.5.  the  results  of non-destructive  tests  carried  out  during  production  and  the  welding 
methods  used  to ensure  good  reproducibility  of cylinders  during  manufacture; 
5.1.6.  a  list of the cylinders,  stating  the numbers  and  markings  as required  in section  6. 
5.2. EEC  inspection  procedure 
5.2.1.  The  inspection  authority  shall: 
— ascertain.that  an approval  certificate  has been  obtained  and  that  the cylinders  con-
form  thereto; 
— check  the documents  giving  data  concerning  the materials  and  the manufacturing 
processes,  in particular  those  specified  in section  2.1.6; 
— ascertain  whether  the technical  requirements  set out in section  2 have  been  met,  and 
in particular  verify  by means  of an external  visual  examination  of each  cylinder 
and an internal  sampling  examination  of between  5 and  10%  of the cylinders  in 
each  batch  whether  the construction  as well  as the inspections  carried  out  by the 
manufacturer  are satisfactory; 
— be present  at the tests  prescribed  in sections  3.1 and  3.2 and  check  their  progress; 
— spot-check  whether  the information  supplied  by the manufacturer  in the list specified 
in subsection  5.1.6  is correct.  Between  5 and  10%  of the cylinders  in each  batch 
shall  be subjected  to this  check; 
— issue  the EEC  inspection  certificate  conforming  to the model  set out in Annex  III 
to this  Directive 
13.9.74 Official  Journal  of the  European  Communities No C 104/67 
5.2.2.  For  the purpose  of carrying  out the two  types  of tests  specified  in sections  3.1 and 
3.2 a random  sample  shall  be taken  from  each  batch  of cylinders  of indentical  shape, 
all having  been  made  from  the same  materials  (steel  plates  identical  as to properties 
and supplier  and  the same  filler  material)  and  produced  on a continuous  basis  using 
the same  welding  techniques  and  inspections  as well  as an identical  heat  treatment, 
the number  of cylinders  comprised  in the sample  being  as shown  in the following 
table: 
No of No of cylinders  subjected  to: 
cylinders 
sampled Mechanical 
tests Bursting 
test 
Batch  of 402  cylinders 
or part  batch  thereof 2 1 1 
Batch  of 1 206 (3 X 402) 
cylinders 6 2 4 
Batch  of 2 412 (6 X 402) 
cylinders 12 3 9 
Depending  on the batch,  the cylinders  sampled  shall  be subjected  to the tests  specified 
in section  3.1 (mechanical  tests)  and  to the test specified  in section  3.2 (bursting  test) 
in accordance  with  the breakdown  in the table  above. 
In the case  of three-piece  cylinders,  the cylinders  taken  as samples  from  each  batch 
shall  undergo  a prior  radiographic  test on each  weld  joint  comprising  100 mm  of the 
longitudinal  weld  and  50 mm  (25 mm  on each  side  of the joint)  of the circumferen-
tial weld  (Fig.  8 in this  Annex)  in order  to check  compliance  with  the conditions 
specified  in subsections  2.4.5.3  and 2.4.5.4. 
If one of the tests  fails  even  partially  to give  satisfaction,  the same  number  of cylinders 
shall  be taken  at random  from  the same  batch  and  subjected  to the type  of test 
which  was  failed. 
If any of these  further  cylinders  fails  to give  satisfaction,  all the cylinders  in that  batch 
shall  be unconditionally  rejected. 
5.2.3.  The  selection  of specimens  and  all the tests  shall  be carried  out in the presence  of a 
representative  of the inspection  authority. 
5.2.4.  All  the cylinders  in the batch  shall  be subjected  to a hydraulic  test  as specified  in 
section  3.3 in the presence  of and  under  the supervision  of a representative  of the 
inspection  authority. 
5.3. Exemption  from  the EEC  inspection 
For any  cylinders  covered  by Article  4 (a) of this  Directive  and  in conformity  with 
the provisions  set out in Article  15 (a) of the Council  Directive  of on  the approxi-
mation  of the laws  of the  Member  States  relating  to the common  provisions  for 
pressure  vessels  and  to the methods  of inspection  and  testing  of such  vessels,  all the 
test and  inspection  operations  prescribed  in section  5.2 shall  be carried  out by the 
manufacturer  on his responsibility. 
The manufacturer  shall  provide  the inspection  authority  with  all the documents  and 
the test and  inspection  reports. 
The presence  of a representative  of the inspection  authority  referred  to in sections  5.2.3 
and 5.2.4  of this  Annex  shall  not be required. 
No C 104/68 Official  Journal  of the  European  Communities 13. 9. 74 
6. MARKING 
6.1. When  all the  prescribed  checks  have  been  carried  out  by the  inspection  authority, 
and provided  that  the  results  are satisfactory,  the inspection  authority  shall  issue  a 
certificate  stating  the checks  which  have  been  carried  out. 
6.2. The  markings  shall  be grouped  together  and  none  may  be stamped  on the  stress-
resistant  shell  of a cylinder. 
6.3. Any  identification  plate  required  shall  be affixed  to the top head  and  have  a minimum 
thickness  of 3 mm. 
6.4. Each  cylinder  shall  be stamped  with  the  symbol  specified  in section  5.3 of 
Annex  I to the Council  Directive  of on  the approximation  of the laws  of the 
Member  States  relating  to the  common  provisions  for  pressure  vessels  and  to the 
methods  for  the  inspecting  and  testing  of such  vessels  for  cylinders  covered  by 
Article  4 (a) of this  Directive  and  the  symbol  of the  EEC  type-approval 
specified  in section  5.1 of Annex  I followed  by the EEC  type-test  symbol  'e' specified 
in section  3.1.1.1  (a) of Annex  II to the Directive  quoted  above  for cylinders  covered 
by Article  4 (b) of this  Directive. 
These  symbols  shall  be followed  by the following  markings: 
6.5. Markings  based  on the construction 
6.5.1.  Relating  to the metal 
A number  indicating  the value  of Rc  in N/mm2  on which  the calculation  was  based. 
The symbol  N (cylinder  in a normalized  condition),  or the  symbol  S (cylinder  in a 
stress-relieved  condition). 
6.5.2.  Relating  to the hydraulic  test 
The value  of the  test  pressure  in bars  marked  in large  digits  at the  centre  and 
above  it the date  of the initial  hydraulic  test  (month  and  year). 
6.5.3.  Relating  to the cylinder  type 
Below  the figures  to the test  pressure,  the weight  of the cylinder  (less  its cock  or valve) 
in kg, and  the  minimum  capacity  of the  cylinder  in litres  guaranteed  by the manu-
facturer. 
The weight  and  the capacity  shall  be expressed  to three  significant  figures,  the third 
figure  being  arrived  at by 'rounding  down'  for the capacity  and  'rounding  up' for the 
weight. 
6.5.4.  Relating  to the origin 
The manufacturer's  mark  and  the serial  number. 
6.5.5.  Example: 
OA/72 
£e 250  N 60  ....6-851 
704/40-5 
13. 9. 74 Official  Journal  of the European  Communities No C 104/69 
Figure  1 
Longitudinal  weld 
f 
V Figure  2 
Circumferential  weld 
Figure  3 
Valve  sleeve  weld 
No C 104/70 Official  Journal  of the European  Communities 13. 9. 74 
Tensile  test  piece 
Bend  test  piece 
(top of weld) (a) Tensile  test  piece 
(d) Bend  test  piece 
(bottom  of weld) 
Figure  4 
Test  pieces  taken  from  two-piece  cylinders 
(c) Tensile  test  piece 
(e) Bend  test  piece 
(top of weld) 
Bend  test  piece 
(bottom  of weld) (a) Tensile  test 
(b) Tensile  test 
"X— 
Tensile  test  piece 
Bend  test  piece 
(top of weld) 
Bend  test  piece 
(bottom  of weld) 
Figure  5 
Test  pieces  taken  from  three-piece  cylinders 
13. 9.74 Official  Journal  of the European  Communities No C 104/71 
Figure  6 
The 'perpendicular  to the weld'  tensile  test piece  (Subsection  3.1.2.2.3) 
25 
No C 104/72  Official  Journal  of the European  Communities  13.  9. 74 
Figure  7 
Cylinder  end 
100 mm 100 mm 
Figure  8 
Dimensions  of weld  joints  undergoing  radiography 
13. 9.74 Official  Journal  of the  European  Communities No C 104/73 
ANNEX  II 
EEC  APPROVAL^CERTIFICATE 
Inspecting  Authority:  Application  of Council  Directive 
No of 
Date:.  EEC  Approval  Code  No 
Designation  of cylinders:  Capacity: 
Manufacturer's  name  and address: 
The undersigned  hereby  declares  that  he has checked  that  the verifications,  tests  and inspections 
specified  in section  4.2 of Annex  I to Council  Directive  No of  have  been  successfully 
performed. 
Cylinders  of the accepted  model  •! are  subject  to EEC  inspection [ are not 
General  observation:  the  drawing  jvhich  was  the subject  of approval  is annexed  hereto. 
Signed  and certified  this day  of at 
(Signature  and  capacity) 
No C 104/74 Official  Journal  of the European  Communities 13. 9. 74 
ANNEX  111 
EEC  INSPECTION  CERTIFICATE 
Inspecting  Authority:  Application  of Council  Directive 
No of 
Date:  EEC  Approval  Code  No 
Designation  of cylinders:  EEC  Type-testing  Code  No .... 
Capacity: 
Manufacturing  batch  No 
Manufacturer's  name  and  address: 
The undersigned  hereby  declares  that  he has checked  that  the verifications,  tests  and inspections 
specified  in section  5.2 of Annex  I to Council  Directive  No of  have  been  successfully 
performed. 
Special  observations: 
General  observations: 
Signed  and certified  this day  of at 
(Signature  and  capacity)