Norsok Z 008

NORSOK STANDARD

Z-008
Rev. 2, Nov. 2001

Criticality analysis for maintenance purposes

This NORSOK standard is developed by NTS with broad industry participation. Please note that whilst every effort
has been made to ensure the accuracy of this standard, neither OLF nor TBL or any of their members will assume
liability for any use thereof. NTS is responsible for the administration andpublication of this standard.
Norwegian Technology Centre
Oscarsgt. 20, Postbox 7072 Majorstuen
N-0306 Oslo
NORWAY
Copyrights reserved

Telephone: + 47 22 59 01 00
Fax: + 47 22 59 01 29
Email: norsok@nts.no
Website: www.nts.no/norsok

NORSOK standard Z-008

Rev. 2, Nov. 2001

Foreword

2

Introduction

2

1

Scope

3

2

Normative references

3

3Definitions and abbreviations
3.1
Definitions
3.2
Abbreviations

4
4
6

4

Application of this NORSOK standard
4.1
General
4.2
Principles for risk evaluation and allocation of maintenance activities
4.3
Safety critical functions
4.4
Inspection of static process equipment

7
7
7
8
8

5

Functional hierarchy and criticality analysis
5.1
General
5.2
Necessary preconditions5.3
System selection
5.4
Main function (MF) definition
5.5
Sub function definition

9
9
10
11
11
12

6

Documentation of the end product

13

7

Application of criticality analysis
7.1
Maintenance program
7.2
Spare parts evaluation
7.3
Conceptual and design evaluation
7.4
Prioritising work orders

14
14
16
17
18

Annex A (informative) Main function descriptionand boundaries

19

Annex B (informative) Simplifying consequence assessment

23

Annex C (informative) Practical examples

25

Annex D (informative) Relations to other NORSOK standards

29

Bibliography

30

NORSOK standard

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NORSOK standard Z-008

Rev. 2, Nov. 2001

Foreword
The NORSOK standards are developed by the Norwegian petroleum industry toensure adequate safety,
value adding and cost effectiveness for existing and future petroleum industry developments.
The NORSOK standards are prepared to complement available international standards and fill the broad
needs of the Norwegian petroleum industry. Where relevant NORSOK standards will be used to provide the
Norwegian industry input to the international standardisation process. Subjectto development and
publication of international standards, the relevant NORSOK standard will be withdrawn.
These NORSOK standards are developed according to the consensus principle generally applicable for
most standards work and according to established procedures defined in NORSOK A-001
The preparation and publication of the NORSOK standards is supported by OLF (The Norwegian Oil
IndustryAssociation) and TBL (Federation of Norwegian Manufacturing Industries). NORSOK standards are
administered and issued by NTS (Norwegian Technology Centre).
All annexes are informative.

Introduction
The purpose of this NORSOK standard is to provide requirements and guidelines for establishing a basis for
preparation and optimisation of maintenance programs for new and in service facilitiesoffshore and onshore
taking into account risks related to:
•
•
•
•

Personnel
Environment
Production loss.
Direct economical cost (everything other than cost of production loss).

The result of this NORSOK standard is applicable for different purposes such as:
•
•
•

Design phase.
Establishing initial maintenance manning requirements, identify hidden failures on critical equipmentand
selection of insurance spare parts.
Preparation for operation.
Development of initial maintenance programs for implementation into maintenance management
systems and selection of ordinary spare parts.
Operational phase.
Optimisation of existing maintenance programs and as a guide for prioritising work orders.

NORSOK standard

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NORSOK standard Z-008

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