BS EN 334-2005 pdf download.Gas pressure regulators for inlet pressures up to 100 bar.
4 ConstructIon requirements
4.1 Basic requirements
4.1.1 General
The main function of a regulator is to maintain the value of the controlled variable within its tolerance field irrespective of the disturbance variables.
Regulators shall not have any continuous discharge of gas into the atmosphere, however, temporary discharges from fixtures may occur.
Regulators shall be designed so that the external tightness and internal sealing shall meet the requirements of 5.2. If in the event of failure of the regulator (e.g. failure of a diaphragm) leakage is possible, a tapping connection of at least DN 10 for any breather line or device shall be provided.
Pressure containing parts induding measuring and test points, which may be dismantled for servicing, adjustment or conversion shall be made pressure tight by mechanical means (e.g. metal to metal joints, o-rings, gaskets, etc.). Jointing compounds, such as liquids and pastes, shall not be used.
Jointing compounds, however, may be used for permanent assemblies and shall remain effective under normal operating conditions.
Pressure containing parts not intended to be dismantled during servicing, adjustment or conversion shall be sealed by means which will show evidence of interference (e.g. lacquer).
Any breather line or device fitted shall be designed to prevent the ingress of foreign materials.
When external protrusions or other external parts need special care to cover the hazards during transport and handling, the manual shall include the provisions to cover these risks.
The motorization energy in a pilot controlled regulator shall be provided by the gas upstream of the regulator.
4.1.2 Gas pressure regulators with integrated safety devices
Additional integrated (same body) safety devices i.e. gas safety shut-off devices (SSD)2 andlor a monitor and specific safety devices in accordance with 4.3.3 shall be functionally independent from the regulator.
This requirement is met if the function of the regulator is not affected in the event of the failure of one or more of the following safety device components:
Further, when the integrated safety device utilizes pipeline gas as a source of energy for its operation this shall be taken from upstream of the regulator.
When the integrated safety device is a slam shut device or a cut-off device or a monitor, the motorization energy for regulator when a piloted controlled type, shall be provided by the gas downstream from the safety device.
4.1.3 End connections
End connections may be one of the following:
flanged connections In accordance with the applicable parts of ISO 7005 (some parts of these documents can be replaced by the equivalent documents when they are available. At the time of writing, this subject is dealt with in EN 1092-1, EN 1092-2, EN 1092-3, EN 1092-4, EN 1759-3, 1759-4 and EN 1759-1;
— flangeless type (e.g. wafer body);
— threaded connections in accordance with ISO 7-1 (this document shall be replaced when equivalent documents are available. At the time of writing some parts of this document are equivalent to EN 10226-1 and some other parts are under study in prEN 10226-2) or ANSI/ASME B1.20.1 (this document shall be replaced by the equivalent document when it is available, At the time of writing this subject is under study in prEN 10226-2) for:
ON 50;
— DN≤8OandPS≤l6bar;
— compression fittings for DN ≤ 50;
butt weld connections in accordance with EN 12627.
4.1.4 Flange ratings
The PN ratings for flanges shall be selected from the following designations:
6-10-16-20-25-40-50- iio
according to the relevant parts of ISO 7005 (some parts of these documents can be replaced by the equivalent documents when they are available. At the time of writing, this subject is dealt with in EN 1092-1, EN 1092-2, EN 1092-3, EN 1092-4, EN 1759-3, EN 1759-4 and EN 1759-1),
The underlined designations are preferred.BS EN 334-2005 pdf download.