One of the most serious dangers occurring in tankers is the escape of gases from tank venting pipes during loading. Recently Thermotank carried out, on behalf of the International Oil Tankers Terminal Safety Group, some experimental tests in order to study the dispersion of hydrocarbon gases escaping from venting pipes of tankers during loading. The results of such tests are contained in the final draft of the International Oil Tanker Terminal Safety Group Safety Guide Standing Committee. Such tests were carried out on models in an aerodynamic tunnel, employing a mixture of 50 percent air and 50 percent butane in volume, whose properties are very near to those of crude oil gas mixtures, and a mixture of 50 percent air and 50 percent butane in volume, which may be compared with distillate gas mixtures (petrol, etc.). On the basis of experimental results, diagrams were plotted by means of which it is possible to determine the position and height of venting pipes depending upon predetermined parameters, thus avoiding formation of explosive gas mixtures on deck and around superstructures. The test results have a remarkable importance both because they enable the building of a realistic picture of gas outflow from tanks during loading and because from them results a philosophy of designing venting pipes for tankers different from the traditional one. The design has to be based upon two fundamental points. The first point is to insure dispersion of gases, by fitting single venting pipes or venting pipes discharging into a common main having its outlet placed at a height on deck and at a distance from superstructures not less than the values derived as a result of the tests. The second point results from the first one and namely is given by the necessity to avoid that in any case the pressure in tanks exceed a pre-fixed value, of about 0.2 kb/cm. sq., beyond which damages to tank structures may occur.

  • Corporate Authors:

    Registro Italiano Navale

    20 Via Vente Settembre
    Genoa,   Italy 
  • Authors:
    • Selvaggi, Mario
  • Publication Date: 1970-6

Media Info

  • Pagination: 6 p.
  • Serial:
    • Issue Number: 38

Subject/Index Terms

Filing Info

  • Accession Number: 00014644
  • Record Type: Publication
  • Report/Paper Numbers: Italian
  • Files: TRIS
  • Created Date: Aug 12 1972 12:00AM