BS EN 334:2019

What is BS EN 334 - Gas pressure regulators about?  

BS EN 334 discusses the gas pressure regulators. Gas pressure regulators reduce high-pressure gas in a cylinder or process line to a lower, usable level as it passes to another piece of equipment. BS EN 334 specifies constructional, functional, testing, marking, sizing and documentation requirements of gas pressure regulators:  

• For inlet pressures up to 100 bar and nominal diameters up to DN 400 
• For an operating temperature range from – 20 °C to +60 °C 

which operate with fuel gases of the 1st and 2nd family as defined in EN 437:2018 [1], used in the pressure control stations in accordance with EN 12186 or EN 12279, in transmission and distribution networks and in commercial and industrial installations. BS EN 334 applies to regulators which use the pipeline gas as a source of control energy unassisted by any external power source.  

Note 1: The regulator may incorporate a second regulator, used as a monitor, complying with the requirements in BS EN 334 

Note 2: This document does not apply to:  

• Regulators upstream from/on/in domestic gas-consuming appliances which are installed downstream of domestic gas meters 
• Regulators designed to be incorporated into pressure control systems used in service lines2) with volumetric flow rate ≤ 200 m3/h at normal conditions and inlet pressure ≤ 5 bar 
• Regulators for which a specific document exists (e.g. En 88-1 and en 88-2, etc.) 
• Industrial process control valves in accordance with en 1349 

Who is BS EN 334 - Gas pressure regulators for? 

BS EN 334 on gas pressure regulators is useful for: 

• LPG equipment manufacturers 
• Cylinder manufacturers 
• Design engineers 
• Quality control personnel 
• Research and development facilities 

Why should you use BS EN 334 - Gas pressure regulators?  

Gas pressure regulators prevent damage to equipment and tools. Without such devices, pressure could become too great for equipment operation and pipes could easily burst. The gas pressure regulator is a device whose function is to maintain the value of the controlled variable within its tolerance field irrespective of disturbance variables. BS EN 334 lists some suitable materials for pressure bearing parts, inner metallic partition walls, auxiliary devices, integral process and sense lines, connectors and fasteners. The continued integrity of gas pressure regulators is ensured by suitable surveillance checks and maintenance. For periodic functional checks and maintenance, it is common to refer to national regulations/standards where existing or users/manufacturers practices. 

In BS EN 334, both pressure regulators that can be classified as “safety accessories” by themselves (monitors) according to European legislation on pressure equipment, as well as regulators that can be used to provide the necessary pressure protection through redundancy (for example, pressure regulator with integrated safety shut-off device, pressure regulator + in-line monitor, pressure regulator + safety shut off the device), are considered. Using BS EN 334 you can specify constructional, functional, testing, marking, sizing and documentation requirements of gas pressure regulators. 

What’s changed since the last update?  

BS EN 334:2019 supersedes BS EN 334:2005+A1:2009. BS EN 334:2019 includes some technical changes with respect to BS EN 334:2005+A1:2009. These include: 

• Normative references have been updated 
• Terms and definitions have been added 
• Flange ratings as per the available European standards both with pn and class designations have been included: pn 20 and pn 50 flanges, as per iso 7005-2, concern spheroidal graphite cast iron only because at the time of writing, there was no en standard available for class designation 
• Minimum requirements for elastomeric materials following the approach already have been adopted for metallic materials 
• “Fail open” and “fail close” characteristics have been improved as per the cen rules i.e., implementing for each characteristic, were originally missed, the relevant requirement/test method/ acceptance criteria