AS 4632:2020 pdf free.Over-pressure and under-pressure shut-off devices.
2.1 Materials
2.1.1 Continuity of satisfactory operation
Materials used in the construction shall be such that continuity of satisfactory operation can be expected during normal usage within the manufacturer’s specification.
2.1.2 Suitability of materials for conditions of use
Materials and finishes, including dressings and lubricants, that are used in the construction shall be suitable for the conditions of use (e.g. corrosion, temperature, handling).
2.1.3 MaterIals in contact with gas
Materials in contact with the gas, including lubricants, dressings and jointing compounds, shall be suitable for use with all gases.
2.1.4 Melting point of metallic materials
The device body related structural components and retaining devices shall be made of metallic materials with a melting point not less than 430 °C.
Conformance shall be assessed by testing with the method in Clause 8.5.
2.1.5 Copper containing alloy parts
Copper containing alloy parts shall be resistant to stress-corrosion cracking when tested in accordance with ISO 6957 or AS 2136.
2.2 Construction
2.2.1 Continuity of satisfactory operation
Construction shall ensure continued safe operation during the usage stated in the manufacturer’s specification.
2.2.2 Castings and hot pressings
All castings and hot pressings shall be clean and sound, free from laps, blow holes and pitting. All surfaces not machine finished shall be clean, smooth and free from sand.
2.2.3 Sealing of porous castings or cracks
Porous castings or cracks in gas-carrying parts shall he sealed by an accepted method for the impregnation of castings, such as vacuum impregnation.
2.2.4 Assembled device to be clean
The assembled device shall not contain dirt, casting sand. swarf or other foreign matter. There shall be no excess diaphragm dressing, lubrication or jointing compound in the device.
2.2.5 Accidental displacement of parts
Every part shall be secured against accidental displacement and shall be constructed to maintain a fixed relationship between essential parts under normal and reasonable conditions of handling and usage to ensure continued conformance to this Standard.
2.2.6 Attachment of knobs, handles, dials and pointers
Knobs, handles, movable dials and pointers, where supplied, shall be securely attached to their spindles.
2.2.7 Springs
Springs shall be resistant to corrosion. The ends of a helical spring shall be flat and in a plane perpendicular to the axis of the spring. The coils ofa cylindrical helical spring shall not be able to overlap.
2.2.8 Securing of parts together
Adhesives shall not be used for securing parts together without means of additional mechanical fixing.
Adhesives may be used for labels.
2.2.9 Sharp edges
Any accessible part(s) shall be free from sharp edges that may cause damage or injury when installed or adjusted (if applicable).
2.2.10 Holes for assembly or mounting
Holes intended for the assembly of parts or for mounting shall not open into gasways. Holes shall provide a minimum wall thickness of 1 mm from gasways.
2.2.11 Permanent sealing of non-functional holes
Non-functional holes used for manufacturing and forming a passage between gasways and the atmosphere shall be permanently sealed by mechanical means.AS 4632 pdf download.