The Simple Pressure Vessels (Safety) Regulations 2016 PART 1 — Materials

1

Materials used in the manufacture of a vessel must be selected according to the intended use of the vessel and in accordance with paragraphs 2 to 9.

Pressurised parts

2

The materials used for manufacturing the pressurised parts of the vessel must be— (a) capable of being welded; (b) ductile and tough, so that a rupture at minimum working temperature does not give rise to either fragmentation or brittle-type fracture; (c) not adversely affected by ageing.

Pressurised parts

3

For steel vessels, the material must in addition meet the requirements set out in paragraph 5 and, for aluminium or aluminium alloy vessels, those set out in paragraph 6.

4

The materials must be accompanied by an inspection slip as defined in paragraph 21(b) of Schedule 2, drawn up by the producer of the materials.

Steel vessels

5

Non-alloy quality steels must meet the following requirements— (a) they must be non-effervescent and supplied after normalisation treatment, or in an equivalent state; (b) the content per product of carbon must be less than 0.25% and that of sulphur and phosphorous must each be less than 0.05% (c) they must have the following mechanical properties per product— (i) the maximum tensile strength Rm, max must be less than 580 N/mm 2; (ii) the elongation after fracture must be: if test pieces are taken parallel to the direction of rolling: or, if test pieces are taken perpendicular to the direction of rolling: (iii) the average bending rupture energy (KCV) for three longitudinal test pieces at minimum working temperature must not be less than 35 J/cm 2 . Not more than one of the three figures may be less than 35 J/cm 2 , with a minimum of 25 J/cm 2 . In the case of steels intended to be used in the manufacture of vessels the minimum working temperature of which is lower than - 10°C and the wall thickness of which exceeds 5 mm, this property must be checked.

Aluminium vessels

6

(1) Non-alloy aluminium must have an aluminium content of at least 99.5% and the alloys referred to in regulation 2(1)(b) (interpretation) must display adequate resistance to intercrystalline corrosion at maximum working temperature. (2) Moreover, these materials must satisfy the following requirements— (a) they must by supplied in an annealed state; (b) they must have the following mechanical characteristics per product— (i) the maximum tensile strength R m, max must be no more than 350 N/mm 2 , (ii) the elongation after fracture must be— (aa) A ≥ 16% if the test piece is taken parallel to the direction of rolling; (bb) A ≥ 14% if the test piece is taken perpendicular to the direction of rolling.

Welding materials

7

The welding materials used to manufacture the welds on or of the vessel must be appropriate to and compatible with the materials to be welded.

Accessories contributing to the strength of the vessel

8

(1) Accessories contributing to the strength of the vessel (for example bolts and nuts) must be made— (a) of a material specified in paragraphs 2 to 6; or (b) of other kinds of steel, aluminium or an appropriate aluminium alloy compatible with materials used for the manufacture of pressurised parts. (2) The materials referred to in sub-paragraph (1)(b) must, at minimum working temperature, have an appropriate elongation after fracture and bending rupture energy.

Non-pressurised parts

9

All unpressurised parts of welded vessels must be of materials which are compatible with that of the components to which they are welded.

Symbols

10

In this Part— (a) “ A ” means elongation after fracture ( (b) “ A 80 mm ” means elongation after fracture ( (c) “ KCV ” means bending rupture energy in J/cm 2 (d) “ R m, max ” means maximum tensile strength in N/mm 2