EN 14620 referred to in Spain as the UNE-EN 14620-1:2008 standard, which applies to flat-bottom tanks used for cryogenic storage. Understanding its requirements is the first step to ensuring the safety of these facilities.
What is the UNE-EN 14620 standard and what does it govern?
The Spanish adaptation of the EN 14620 standard is used for the design and manufacture of cylindrical, vertical, flat-bottomed steel tanks, which are built on site for the storage of refrigerated liquefied gases with service temperatures between 0º and -165ºC.
This tank standard covers the whole 5-step process of tank design and construction, referring specifically to:
– Part 1: general information
– Part 2: metallic components
– Part 3: concrete components
– Part 4: Insulating components
– Part 5: Testing, drying, venting and cooling down
It applies to storage tanks with an atmospheric boiling point below ambient temperature in their liquid and vapour phase. The balance between the two is achieved by cooling the product to a temperature at or just below its atmospheric boiling point by adding excess pressure in the storage tank.
Who is aimed at: should your company apply it?
This standard should apply to all companies that work with and therefore store large volumes of refrigerated liquefied gas products. This therefore includes typical products such as methane, ethane, propane, butane, ethylene, propylene and butadiene. To this list should be added liquefied natural gases (LNG) and liquefied petroleum gases (LPG).
Differences between API 620 and UNE-EN 14620
The API 620 and EN 14620 standards have very similar general characteristics, although there are significant differences in their recommendations regarding the controls established and in terms of tank design.
It should also be noted that API 620, especially in its Annex Q, covers a wider temperature range because in theory it applies to tanks of temperature -325ºF (-198ºC) or higher. While in theory this means that EN 14620 should not be used on LIN (-196ºC), LOX (-183ºC) and LAR (-185ºC) tanks, the reality is that it does apply.
Other tank standards you should know about
The design of cryogenic tanks must take into account various safety standards, which are related to the gas to be stored and the temperature of the operation to be carried out. This also influences the selection of the materials to be used along with the insulation system. Likewise, it is necessary to bear in mind that API 625, section 5, describes the safety measures to be taken according to the risk studies carried out and the recommendations of the property.
It should also be noted that in Europe there is no obligation to follow a particular standard. However, while Western European countries rely essentially on American standards, the rest opt for European standards.
Also, when it comes to the manufacture of flat-bottom cryogenic tanks, we must bear in mind that they have a pressure of less than 500 mbarg. They ought therefore theoretically not to be subject to the standards that apply to pressure equipment, such as 2014/68/EU, TRCU-032/2013 or ASME. In any case, each country may ask for its own standards to be applied, such as the GB in China, the KSA in Korea, the Japanese JIS or the Israeli IIS.
Finally, compliance is often requested to some specific standards in specific aspects:
- In the case of LNG tanks, the reference standard is NFPA 59A.
- For safety equipment, API 2000 is requested.
- Conformity with EN ISO 14122-1/3 or/and OSHA 1910.23/24 is requested for tank accesses.
In short, a familiarity with EN 14620 and all standards relating to cryogenic safety tanks is a vital step in ensuring the safety of these installations.