ISO 5171:2019 pdf download – Gas welding equipment – Pressure gauges used in welding, cutting and allied processes
1 Scope
This document specifies requirements for Bourdon-tube pressure gauges normally used with compressed gas systems at pressures up to 30 MPa (300 bar) in welding, cutting and alied processes. It also covers use for dissolved acetylene and for liquefied gases under pressure.
It does not cover gauges for acetylene in acetylene-manufacturing plants.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 7-1, Pipe threads where pressure-tight joints are made on the threads – Part 1: Dimensions, tolerances and designation
ISO 228-1, Pipe threads where pressure-tight joints are not made on the threads – Part 1: Dimensions,tolerances and designation
ISO 497, Guide to the choice of series of preferred numbers and of series containing more rounded values of preferred numbers
ISO 4589-2:2017, Plastics – – Determination of burning behaviour by oxygen index – – Part 2: Ambient- temperature test
ISO 9539, Gas welding equipment一Materials for equipment used in gas welding, cutting and alied processes
ISO 10102, Assembly tools for screws and nuts – . Double-headed open-ended engineers’ wrenches – Outside dimensions
ISO 14114, Gas welding equipment – Acetylene manifold systems for welding, cutting and alied processes – General requirements
ISO 15296, Gas welding equipment – Vocabulary ANSI/ASME B1.20.1), Pipe threads, general purpose (inch)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 15296 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
– ISO Online browsing platform: available at https://www.iso.org/obp
– IEC Electropedia: available at http://www.electropedia.org/
5.1.1 General
The materials of the pressure gauge components in contact with the gas shall have adequate resistance to the chemical action of the gas under operating conditions. Bourdon tubes and other parts in contact with acetylene gas shall conform to ISO 9539.
5.1.2 Oxygen pressure gauges
Bourdon tubes and other parts in contact with the gas shall be resistant to the action of the oxygen and shall not be flammable under operating conditions (e.g. working pressures and temperatures). Thread sealants or sealing rings shall also be resistant to the action of the oxygen and shall not be flammable under operating conditions (e.g. working pressures and temperatures). Components in contact with oxygen gas shall conform to IS0 9539. Only lubricants suitable for use in oxygen at the service pressure and temperature shall be used.
5.2.1.3 Torsion
After application of the torque of 10 Nm according to 8.3.1 for a period of not less than 30 s, the pressure gauge shall satisfy the conditions of accuracy specified in 5.21.1. After application of the torque of 25 Nm according to 8.3.2 for a period of not less than 30 s, the pressure gauge shall be leak-tight at a pressure corresponding to the maximum scale reading, The tests above apply to gauges with connecting threads of a nominal size of 1/4. Connecting threads of nominal size 1/8 shall only be used when equivalent safety can be demonstrated.