Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights.

Valves, Subcommittee SC 1, Design, manufacture, marking and testing.ISO 10497 was prepared by Technical Committee ISO/TC 153,, Subcommittee SC 1,

This third edition cancels and replaces the second edition ( ISO 10497:2004 ), which has been technically revised.

Introduction

This International Standard covers the requirements and method for evaluating the performance of valves when they are exposed to defined fire conditions. The performance requirements establish limits of acceptability of a valve, regardless of size or pressure rating. The burn period has been established to represent the maximum time required to extinguish most fires. Fires of longer duration are considered to be of major magnitude, with consequences greater than those anticipated in the test.

The test pressure during the burn is set at 0,2 MPa (2 bar) for soft-seated valves rated PN 10, PN 16, PN 25 and PN 40, Class 150 and Class 300, to better simulate the conditions that would be expected in a process plant when a fire is detected and pumps are shut down. In this case, the source of pressure in the system is the hydrostatic head resulting from liquid levels in towers and vessels. This situation is approximated by this lower test pressure.

In production facilities, valves are typically of a higher rating and the pressure source is not easily reduced when a fire is detected. Therefore, for all other valves, the test pressure during the burn is set at a higher value to better simulate the expected service conditions in these facilities.

Use of this International Standard assumes that the execution of its provisions is entrusted to appropriately qualified and experienced personnel, because it calls for procedures that can be injurious to health, if adequate precautions are not taken. This International Standard refers only to technical suitability and does not absolve the user from legal obligations relating to health and safety at any stage of the procedure.

1   Scope

This International Standard specifies fire type-testing requirements and a fire type-test method for confirming the pressure-containing capability of a valve under pressure during and after the fire test. It is not applicable to the testing requirements for valve actuators other than manually operated gear boxes or similar mechanisms when these form part of the normal valve assembly. Other types of valve actuators (e.g. electrical, pneumatic or hydraulic) can need special protection to operate in the environment considered in this valve test, and the fire testing of such actuators is outside the scope of this International Standard.

Fire test certificates of valves previously tested according to previous editions of ISO 10497 and to similar internationally recognized fire test standards are also acceptable.

NOTE For the purposes of this International Standard, the terms ?fire type-test? and ?fire test? are synonymous.

2   Normative references

The following referenced documents are indispensable for the application 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

• IEC 60584-2,

  Thermocouples ? Part 2: Tolerances

3   Terms and definitions

For the purposes of this document, the following terms and definitions apply.

3.1

nominal size

DN

alphanumeric designation of size for components of a pipework system, which is used for reference purposes, comprising the letters DN followed by a dimensionless whole number which is indirectly related to the physical size, in millimetres, of the bore or outside diameter of the end connections

Note 1 to entry:

Adapted from ISO 6708:?, definition 2.1.

3.2

nominal pressure

PN

numerical designation relating to pressure which is a convenient rounded number for reference purposes, and which comprises the letters PN followed by the appropriate reference number

Note 1 to entry:

It is intended that all equipment of the same nominal size (DN) designated by the same PN number have compatible mating dimensions.

Note 2 to entry:

The maximum allowable pressure depends on materials, design and working temperatures, and is selected from the tables of pressure/temperature ratings given in the appropriate standards.

Note 3 to entry:

Adapted from ISO 7268:?, Clause 2.1.

3.3

NPS

alphanumeric designation of size for components of a pipework system, which is used for reference purposes, and which comprises the letters NPS followed by a dimensionless number indirectly related to the physical size of the bore or outside diameter of the end connections

Note 1 to entry:

The number following the letters NPS does not represent a measurable value and is not intended to be used for calculation purposes except where specified in the relevant standard.

3.4

class

alphanumeric designation used for reference purposes related to a combination of mechanical and dimensional characteristics of a component of a pipework system, which comprises the word ?Class? followed by a dimensionless whole number

Note 1 to entry:

The number following the word ?Class? does not represent a measurable value and is not intended to be used for calculation purposes except where specified in the relevant standard.

3.5

symmetric seated valve

valve with an internal construction, which has a plane of symmetry perpendicular to the axis of the body ends

Note 1 to entry:

This is a valve where both seat and sealing elements are identical.

3.6

asymmetric seated valve

valve with an internal construction, which has no plane of symmetry perpendicular to the axis of the body ends

Note 1 to entry:

This is a valve with a single seat offset from the shaft centreline.

3.7

soft seat

soft seal

seat or sealing element made from, or including, a significant amount of thermoplastic or elastomeric material

Only informative sections of standards are publicly available. To view the full content, you will need to purchase the standard by clicking on the "Buy" button.

Bibliography

[1]

ISO 6708:?2),

Pipework components ? Definition and selection of DN, NPS and A

[2]

ISO 7268:?3),

Pipe components ? Definition and selection of PN, Class and K

[3]

ISO 10423,

Petroleum and natural gas industries ? Drilling and production equipment ? Wellhead and christmas tree equipment

[4]

EN 736-3,

Valves ? Terminology ? Part 3: Definition of terms

[5]

EN 1333,

Flanges and their joints ? Pipework components ? Definition and selection of PN

© 2010 ISO ? All rights reserved