Description of BS EN 1993-4-2:2007+A1:2017 2018

1. Part 4-2 of Eurocode 3 provides principles and application rules for the structural design of vertical cylindrical, conical and pedestal above ground steel tanks for the storage of liquid products with the following characteristics:

   1. tanks with capacity greater than 100 m³ (100 000 l);

   2. tanks that have significant fabrication or assembly on site;

   3. shop-fabricated tanks with conical bottoms, supported on skirts or columns;

   4. tanks with characteristic internal pressures above the liquid surface not more negative than –0,1 bar and not greater than 0,5 bar¹⁾;5)

   5. design metal temperatures limited to the ranges:

      1. tanks constructed using structural steel grades, –50°C < T < +300°C;

      2. tanks constructed using austenitic stainless steels, –165°C < T < +300°C;

      3. tanks constructed with special steel grades that have defined yield strengths up to higher temperatures, –165°C < T < the maximum defined temperature for the grade;

      4. tanks susceptible to failure by fatigue, T < 150°C;

   6. in cylindrical ground-supported tanks, the maximum design liquid level not higher than the top of the cylindrical shell.

2. This Part 4.2 is concerned only with the requirements for resistance and stability of steel tanks. Other design requirements are covered by EN 14015 for ambient temperature tanks and by EN 14620 for cryogenic tanks, and by EN 1090 for fabrication and erection considerations. These other requirements include foundations and settlement, fabrication, erection and testing, functional performance, and details like man-holes, flanges, and filling devices.

3. Provisions concerning the special requirements of seismic design are provided in EN 1998-4 (Eurocode 8 Part 4 “Design of structures for earthquake resistance: Silos, tanks and pipelines”), which complements the provisions of Eurocode 3 specifically for this purpose.

4. The design of a supporting structure for a tank is dealt with in EN 1993-1-1.

5. The design of an aluminium roof structure on a steel tank is dealt with in EN 1999-1-5.

6. Foundations in reinforced concrete for steel tanks are dealt with in EN 1992 and EN 1997.

7. Numerical values of the specific actions on steel tanks to be taken into account in the design are given in EN 1991-4 “Actions on Silos and Tanks”. Additional provisions for tank actions are given in annex A to this Part 4.2 of Eurocode 3.

8. This Part 4-2 does not cover:

   • tanks of rectangular planform;

   • tanks with capacity below 100 m³;

   • tanks exposed to fire (refer to EN 1993-1-2);

   • tanks with dished ends and diameter less than 5 m;

   • cylindrical tanks with an aspect ratio of height to diameter greater than 3.

9. The circular planform tanks covered by this standard are restricted to axisymmetric structures, though they can be subject to unsymmetrical actions, and can be unsymmetrically supported.

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