ČSN EN 334 (38 6445)

This document 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 also in commercial and industrial installations.
"Gas pressure regulators" hereafter will be called "regulators" except in the titles.
For standard regulators when used in pressure control stations complying with EN 12186 or EN 12279, the Annex ZA lists all applicable essential safety requirements of the European legislation on pressure equipment except external and internal corrosion resistance for applications in corrosive environment.
This document considers the following temperature classes/types of regulators:
- temperature class 1: operating temperature range from -10 °C to 60 °C;
- temperature class 2: operating temperature range from -20 °C to 60 °C;
- type IS: (integral strength type);
- type DS: (differential strength type).
This document applies to regulators which use the pipeline gas as a source of control energy unassisted by any external power source.
The regulator may incorporate a second regulator, used as monitor, complying with the requirements in this document.
The regulator may incorporate a safety shut off device (SSD) complying with the requirements of EN 14382.
The regulator may incorporate a creep (venting) relief device, complying with the requirements in Annex E and/or a vent limiter, complying with the requirements in Annex I.
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.
The informative Annex G of this document lists some suitable materials for pressure bearing parts, inner metallic partition walls, auxiliary devices, integral process and sensing lines, connectors and fasteners. Other materials may be used when complying with the restrictions given in Table 5.
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.
This document has introduced the reaction of the pressure regulators to the specified reasonable expected failures in terms of "fail close" and "fail open" pressure regulator types, but it should be considered that there are other types of failures whose consequences can bring to the same reactions (these risks are covered via redundancy as per EN 12186) and that residual hazards will be reduced by a suitable surveillance in use / maintenance.
In this document, 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 (e.g. pressure regulator with integrated safety shut-off device, pressure regulator + in-line monitor, pressure regulator + safety shut off device) are considered.
The provisions in this document are in line with the state of art at the moment of writing.
This document does not intend to limit the improvement of actual provisions (materials, requirements, test methods, acceptance criteria, etc.) or the developing of new provisions for gas pressure regulators where they are suitable to ensure an equivalent level of reliability.
Some clauses of this standard should be re-considered at the time when characteristics for non-conventional gases will be available.