CEN/TC 221/SC 1 - Tanks

This document specifies the requirements for metallic shop fabricated cylindrical, horizontal steel tanks, single and double skin for the aboveground storage of water polluting liquids (both flammable and non-flammable) within the following limits:
-   from 800 mm up to 3 000 mm nominal diameter and,
-   up to a maximum overall length of 6 times the nominal diameter and,
-   for liquids with a maximum density of up to 1,9 kg/l and,
-   with an operating pressure (Po) of maximum 1,5 bar (abs.) and,
-   where double skin tanks with a vacuum leak detection system are used the cinematic viscosity of the stored media shall not exceed 5 ´ 10-3 m2/s.
This document is applicable for normal ambient temperature conditions (- 20 °C to + 50 °C). Where temperatures are outside this range, additional requirements need to be taken into account.
This document is not applicable for the storage of liquids having dangerous good classes listed in Table 1 because of the special dangers involved.
Table 1 - List of dangerous goods the storage of which are not covered by this document
UN-classification   Storage media
Class 1                     Explosives
Class 4.2                  Substances liable to spontaneous combustion
Class 4.3                  Substances which in contact with water emit flammable gases
Class 5.2                  Organic peroxides
Class 6.2                  Infectious substances
Class 7                   Radioactive material, hydrocyanic or hydrocyanic solvent liquids, metalcarbonyls, hydrofluoracid, bromide liquids
NOTE   The classifications referred to are those adopted by the United Nations Committee of Experts on the Transport of Dangerous Goods (not to be interpreted as tank classes described in 3.1.4).
This document does not cover the installation of tanks which might be subject to local regulations involving pollution control.

The Standard specifies the requirements for shop fabricated cylindrical, horizontal tanks, single and double skin for underground storage of water polluting liquids (both flammable and non-flammable). The standard is applicable for normal operating conditions (-20°C to +50°C). Where temperatures can fall below this range, additional requirements shall be taken into account. Quittance on liquid material combinations is given in annex B. The standard is not applicable for liquids causing special danger. The standard does not deal with internal coating.