SCHEDULE 1Essential Safety Requirements

PART 1Materials

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/mm2;

(ii)

the elongation after fracture must be:

if test pieces are taken parallel to the direction of rolling:

thickness ≥ 3 mm:

A

≥ 22%,

thickness < 3 mm:

A 80 mm

≥ 17%,

or, if test pieces are taken perpendicular to the direction of rolling:

thickness ≥ 3 mm:

A

≥ 20%,

thickness < 3 mm:

A80 mm

≥15%,

(iii)

the average bending rupture energy (KCV) for three longitudinal test pieces at minimum working temperature must not be less than 35 J/cm2. Not more than one of the three figures may be less than 35 J/cm2, with a minimum of 25J/cm2. 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.