AS NZS 3996:2019 pdf free.Access covers and grates.
2.1 GENERAL
The materials used in the manufacture and supply of access covers, inspection covers, road grates and frames shall conform to the applicable requirements of this Section. The effects of corrosion, fire durability, thermal expansion, degradation by ultraviolet radiation, serviceability, water absorption, creep. fatigue, impact skid resistance, abrasion and wear shall be taken into account.
2.2 CAST IRON
Cast metal grates and covers for water industry use (i.e. water supply and sewerage applications) shall be manufactured from spheroidal graphite cast iron (hereafter called ductile iron) conforming to the requirements specified in Iso 1083 or ISO 17804 for grades with a specified minimum tensile strength of 500 MPa—800 MPa as well as a specified minimum elongation of 10%.
Cast metal grates and covers for all other applications shall be either—
(a) hake graphite cast iron (hereafter called grey iron) of a quality not less than that specified in AS 1830 for Grade T—220; or
(b) ductile iron be in accordance with the requirements specified in AS 1831 for Grade 500/7, or Grade 600/3, as selected by the manufacturer to suit the design and dimensions of the unit.
2.3 FABRICATED MILD STEEL
Mild steel used in the manufacture of covers/grates shall meet the requirements of one of the following steels:
(a) AS/NZS 3678 Grade 250.
(b) AS/NZS 3679.1 Grade 300.
(c) AS/NZS 1594 Grades HA250, HU250, HA300 or HU300.
(d) ISO 4995 Grade 11R235 or HR275.
Welding shall conform to AS/NZS 1554.1 Category GP except for Class D to G
covers/grates, which shall conform to AS/NZS 1554.1 Category SP.
2.4 STAINLESS STEEL
Stainless steel used for the manufacture of grates and covers shall be either wrought or cast austenitic stainless steel.
Wrought fabrications shall be manufactured from material meeting the requirements of
Grade 304, 304L, 316 or 316L to ASTM A240 (for sheet and plate) and ASTM A276,
ASTM A555 and ASTM A580 (for bar and wire) or to the equivalent ISO or EN Standards.
Cast grades shall be those with equivalent corrosion resistance.
Welding shall be in accordance with AS/NZS 1 554.6 Category 2B except for Class D to G covers/grates which shall conform to AS/NZS 1554.6 Category lB.
The finish of the grates and covers shall be either pickled, passivated or electropolished in accordance with AS/NZS 1554.6. Stainless steel components shall be passivated in accordance with ASTM A380.AS NZS 3996 pdf download.