For shells not of a circular cross-section, for example box-shaped or elliptical shells, which cannot be
calculated according to 6.8.2.1.4 and standards or technical code mentioned therein, the ability to
withstand the permissible stress may be demonstrated by a pressure test specified by the competent
authority.
These tanks shall meet the requirements of sub-section 6.8.2.1 other than 6.8.2.1.3, 6.8.2.1.4 and
6.8.2.1.13 to 6.8.2.1.22.
The thickness of these shells shall not be less than the values given in the table below:
 
 

Material

Minimum thickness

Austenitic stainless steels

2.5 mm

Other steels

3 mm

Aluminium alloys

4 mm

Pure aluminium of 99.80%

6 mm

Protection of the tank against damage through lateral impact or overturning shall be provided.
Protection shall be provided according to 6.8.2.1.20 or the competent authority shall approve
alternative protection measures.

By derogation from the requirements of 6.8.2.5.2 tanks do not need to be marked with the tank code
and the special provisions, as applicable.

Tanks with a capacity of less than 1 000 litres

The construction of these tanks shall meet the requirements of sub-section 6.8.2.1 other than 6.8.2.1.3,
6.8.2.1.4, 6.8.2.1.6, 6.8.2.1.10 to 6.8.2.1.23 and 6.8.2.1.28.

The equipment of these tanks shall meet the requirements of 6.8.2.2.1. For UN Nos. 1942 and 3375,
the tank shall meet the requirements of Chapters 4.3 and 6.8 concerning breather devices and, in
addition, shall have bursting discs or other suitable means of emergency pressure relief, approved by
the competent authority of the country of use.

The thickness of these shells shall not be less than the values given in the table below:

Material

Minimum thickness

Austenitic stainless steels

2.5 mm

Other steels

3 mm

Aluminium alloys

4 mm

Pure aluminium of 99.80%

6 mm

 

Tanks may have constructional parts that are without a radius of convexity. Alternative supportive
measures may be curved walls, corrugated walls or ribs. In at least one direction the distance between
parallel supports on each side of the tank shall not be greater than 100 times the wall thickness.

Welds shall be skilfully made and shall afford the fullest safety. Welding shall be performed by
skilled welders using a welding process whose effectiveness (including any heat treatments required)
has been demonstrated by test.

The requirements of 6.8.2.4 do not apply. However, the initial and periodic inspections of these tanks
shall be carried out under the responsibility of the user or owner of the MEMU. Shells and their
equipment shall be subject to visual examination of their external and internal condition and a
leakproofness test to the satisfaction of the competent authority at least every three years.

The requirements for type approval of 6.8.2.3 and for marking of 6.8.2.5 do not apply.

Items of equipment

Tanks with bottom discharge for UN 1942 and UN 3375 shall have at least two closures. One of these
closures may be the product mixing or discharge pump or auger.

Any piping after the first closure shall be of a fusible material (i.e. rubber hose) or have fusible
elements.

In order to avoid any loss of contents in the event of damage to the external pumps and discharge
fittings (pipes), the first closure and its seatings shall be protected against the danger of being
wrenched off by external stresses or shall be so designed as to withstand them. The filling and
discharge devices (including flanges or threaded plugs) and protective caps (if any) shall be capable
of being secured against any unintended opening.

Breather devices in accordance with 6.8.2.2.6 on tanks for UN 3375 may be substituted by "goose
necks". Such equipment shall be protected against the danger of being wrenched off by external
stresses or shall be so designed as to withstand them.
Previous Matter Next Matter

adrbook.com - Copyright all rights reserved. © 2015-2018