BS EN 13953 pdf free download

BS EN 13953 pdf free download. LPG equipment and accessories一Pressure relief valves for transportable refillable cylinders for Liquefied Petroleum Gas (LPG).
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp
3.1
liquefied petroleum gas
LPG
low pressure liquefied gas composed of one or more light hydrocarbons which are assigned to UN 1011, UN 1075, UN 1965, UN 1969 or UN 1978 only and which consists mainly of propane, propene, butane, butane isomers, butene with traces of other hydrocarbon gases
3.2
pressure relief valve
PRV
self-closing valve which automatically, without the assistance of any energy other than that of the vapour concerned, discharges vapour at a predetermined pressure
Note 1 to entry: This is known as a “safety valve” in ADR.
3.3
nominal set pressure
predetermined pressure of the pressure relief valve at which the valve is set to start to discharge
3.4
start to discharge pressure
inlet pressure at which a steady stream of bubbles appear at the outlet of a pressure relief valve through
a water seal of not more than 50 mm water column, or other equivalent method
3.5
pop action
rapid opening of the pressure relief valve sealing element so that the pressure relief valve is fully open, resulting from an increase of inlet pressure creating a sudden increase in force and compression of the spring
3.6
overpressu re
pressure increase between the nominal set pressure and the flow rating pressure
Note 1 to entry: Usually expressed as a percentage of nominal set pressure.
3.7
reseat pressure
inlet pressure at which the sealing element effects a seal with the valve seat after the valve has been subjected to pop action
3.8
flow rating pressure
inlet pressure at which the discharge capacity is measured
3.9
discharge capacity
capacity at the flow rating pressure of a pressure relief valve expressed in m3/min of free air at STP
3.10
nominal discharge capacity
minimum discharge capacity at the flow rating pressure expressed in m3/min of free air at STP rounded down to one decimal place
sealing element
non-metallic resilient component which affects a seal by contact with the valve seat
3.12
valve seat
normally raised area of the valve body on to which the sealing element effects a seal
3.13
cylinder valve
primary shutoff device intended for liquid filling and liquid or vapour service fitted to LPG cylinders
Note 1 to entry: The valve can also include additional devices e.g. liquid level indicator, excess flow device, pressure relief valve, sediment tube, non-return valve and eduction tube.
3.14
leak tightness
resistance to leakage to atmosphere across the valve seat or any other pressure containing component when the valve is closed
3.15
Standard Temperature and Pressure
STP
15,6 °C (288,7 K), 1,013 bar absolute (0,10 1 3 MPa absolute)
4 Operating Conditions
4.1 Terms used with PRVs are described graphically in Annex A.
4.2 Valves designed in accordance with this document shall be suitable for:
— a minimum operating temperature of —20 °C.
— a minimum operating temperature of —40 °C for those parts of Europe where valves are subject to more severe temperature conditions. The material and design shall be shown to be satisfactory for operations under these conditions and shall meet the requirements of Annex B. Where the PRV is integral with a cylinder valve suitable for temperature of —40 °C, the PRV shall also be designed and tested for a temperature of —40 °C; and
— a maximum operating temperature of 65 °C.BS EN 13953  pdf download.