AS 2809.3:2021 – Road tank vehicles for dangerous goods Part 3: Road tank vehicles for compressed liquefied gases.
EN 13175. LPG Equipment and accessories — Specification and testing for Liquid Petroleum Gas (LPG)
pressure vessel valves and fittings
UI 125, Standard for Flow Control Valves for Anhydrous Ammonia and LP-Gas
UI 132, Standard for Safely Relief Valves for Anhydrous Ammonia and LP-Gas
1.5 Terms and definitions
For the purpose of this Standard, the definitions given in AS 2809.1 apply.
1.6 New designs and innovations
This Standard does not prevent the use of designs, equipment, materials, methods of assembly, procedures and the like that do not conform with the specific requirements of this Standard, or are not mentioned in it, provided the performance requirements specified herein are met.
Where a specific section does not state a performance requirement, use of components which by assessment and design achieve the same level of safety may be used.
2 Tanks, accessories and components
2.1 General
‘2.1.1 Tank design
The tank, its supports and connections, shall conform to AS 1210 and with any applicable Standard for the particular cargo, with the following qualifications:
(a) The design pressure shall be not less than the equilibrium vapour pressure for the cargo at a temperature of 46 °C, or not less than 700 kPa. An LP Gas tank shall be designed for propane unless it is dedicated to butane service exclusively.
NOTE 1 For those cargoes whose vapour pressure can be below atmospheric prcssurc at winter temperatures, care should he taken to account for the possibility of a negative iwessure In the tank.
NOTE 2 AS 1210 references AS 2872 whIch sets out a method for calculating the temperatures and corresponding pressures of fluids in vessels subject to atmospheric and solar heating in the hottest month of the year In various locations In Australia.
(b) The cargo load and static head for calculation of the dynamic loading shall be calculated on the basis of the mass fill ratio specified in Table 2.1.
(c) Except where otherwise approved, the materials of construction shall be steel alloy that is suitable for and compatible with the cargo.
(d) Screwed connections to the tank shall not exceed 50 mm nominal bore, except for fully internal safety valves.
(e) Safety valves shall be protected so that, in the event of overturn onto a hard surface, their opening will not be prevented and their discharge not restricted.
(1) Each tank shall have a reflective bright metal or gloss white painted surface, except that another colour or finish may be used provided that the design service temperature has been adjusted in accordance with the maximum service temperature requirements of AS 1210.
NOTE An absorptlvity of 0.3 should be used for a typical white paint finish.
An Internal safety control (ISC) valve may be substituted with an Internal valve Incorporating an Integrated Emergency Shut-down system Where this alternative is employed it shall use a control source such as gas detectors or measurement of differential pressure, pressure or flow to detect uncontrolled release and be provided with a control mechanism In accordance with Clause 2.2.4. Where used, gas detectors shall be selected, installed and maintained according to AS/NZS 60079.29.2. Liquid in/out flow opening
Where the opening Is larger than that of a 25 mm nominal bore pipe, an Internal excess-flow valve and a quick-closing internal valve, or an air actuated (ISC) valve, shall be fitted.
Where the ISC valve option is chosen, the opening shall be provided with a minimum of one independently operated positive shut-oft’ valve in addition to the ISC valve, to shut off the line in the event of ISC valve failure. This shut-off valve shall be located as close as practicable to the tank and may be manually operated.
Where the opening is not larger than that of a 25 mm nominal bore pipe, an internal excess-flow valve shall be fitted, together with an external air actuated positive shut-off valve located as close as practicable to the tank.
For dedicated drain connections, art ISC valve plus a manually operated shut-off valve shall be fitted and be located as close as practicable to the tank. The manual valve shall be plugged or capped.
NOTE For pump suction outlets, due to access constraints and the torque required to operate the secondary positive shut-off valve, consideration should be given to installing an air actuator. Liquid in flow only opening; pump bypass return or top fill connection
These connections shall he fitted with openings in accordance with Clause or an internal non- return valve and an air actuated Flanged shut-off valve, provided the opening conforms to the following:
(a) It is in the bottom of the tank.
(b) It provides both an internal thread and flange connection. Vapour connections opening
These connections shall be fitted with openings In accordance with Clause or an internal excess flow valve and an air actuated flanged valve, provided the opening conforms to the following:
(a) It is in the bottom of the tank.
(b) It provides both an internal thread and flange conrwctivn.
(c) The size does not exceed 50 mm nominal bore pipe.