Table of Contents

  1. Purpose
  2. General
  3. Responsibilities
  4. Guidelines
  5. References
  6. Attachments

1. Purpose

The purpose of this guide is to define the information to be submitted to pressure vessel authorities or designated inspection organizations and to list and describe this information.

The guide refers to pressure vessels intended for installation at a fixed location or premise to the extent it refers to the installations as a whole. The information to be submitted for individual pressure vessels is described in ref. 5.8.

Movable pressure vessels such as those on trucks, ships or railway cars are subject to other regulations not further addressed in this guideline.

2. General

2.1 Definitions of Terms Referring to Legislation

The following definitions of terms referring to legislation are used within the framework of this guideline:

- the term 'legislation' is used for acts, laws and decrees issued by federal, state, country, provincial or municipal governments;

- the term 'semi-legislation' is used for rules, official regulations, guidelines and directives issued by governmental organizat­ions (but without having the status of an act, a law or a decree);

- the term 'regulation' without the specification "official" is used for rules, regulations, guidelines etc. issued by non-governmental (thus private or semi-private) organizations such as societies (example : the German "Berufsgenossenschaft der chemischen Industrie"), independent institutions (example : British Standards Institute) or private companies such as insurance companies.

It is noted, that regulations can, by means of acceptance by a governmental organization, in some countries (e.g., Germany) get almost the same power as legislation.

2.2 Definitions of Terms Referring to Responsible Parties

The following definitions of terms referring to responsible parties are used within the framework of this guideline:

- the term 'owner' is used for the person or organization, who has the responsibility for the actual use and the maintenance of a pressure vessels once it is installed at its final location or premise;

- the term 'manufacturer' refers to the person or organization, who is responsible for the engineering, design and fabrication of a pressure vessel;

Note: manufacturers sometimes subcontract, partly or entirely, the engineering and/or work for a pressure vessel; unless specifically arranged otherwise, the responsibility should formally rest with one organization, so that assessment and inspection work are not affected by contractual relations

- the term '(engineering) contractor' is used for the person or organization, who has, acting directly or indirectly as representative of the owner, the responsibility for the specification of the requirements applicable to a pressure vessel to be used by an owner;

- the term 'licensed engineer' is used for a person who (or, more rarely, an organization which) is entitled, by virtue of certain qualifications, to act as independent assessor and/or inspector of pressure vessels.

Note: such qualifications normally include education to a legally defined level in the mechanical/vessel engineering branch followed by successful examination, a certain amount of experience and, sometimes, the membership of a branch organization.

- the term 'authority' is used for a governmental or semi-governmental organization with a certain field of jurisdiction based on legislation;

- the term 'third party' is used for a person or an organization with the responsibility for assessment, inspection and/or acceptance of pressure vessels.

Note: this responsibility can rest on - usually lower degree -legislation (regulations) or on a contract either between an authority or a third party, an owner or a third party or a manufacturer and a third party.

3. Responsibilities

The Authority Engineer has the overall responsibility for the listing and checking of the documents to be submitted to a pressure vessel authority or a designated third party organization. He is also responsible for all contacts with such authorities and organizations.

The correctness of the documents submitted and information given is the responsibility of the engineering group or the department which generated or provided for it.

4. Guidelines

4.1 Legal Viewpoints

4.1.1 Legislative Situation for Pressure Vessels

The information to be submitted about a project to the Pressure Vessel of a given country is very dependent on the country, its legislation history and its degree of industrial development. Some countries (e.g. the Netherlands, Switzerland) have an rather extensive legislation and semi-legislation on pressure vessels, others (e.g. Belgium, Great Britain) rely almost exclusively on internationally accepted design codes such as BS or ASME, again others prefer to apply locally developed and accepted regulation systems (e.g. Germany with AD-Merk­blät­ter and DIN, France with CODAP and NF).

At present, the approach of pressure vessel inspection by others than the manufacturers and the owners of the vessels is also becoming affected by directives issued by supranational organizations such as the European Economic Union (EEU). These directives have no direct impact on their subjects, but should be incorporated into the legislation of all member countries with the intent, that the approach in the member countries will be the same (harmonization). Examples of these directives are noted in ref. 5.9 and 5.10; they have been worked out in different ways in locally issued and valid documents.

4.1.2 Positions of Parties

The positions of the various parties such as:

- Owner of a pressure vessel
- Manufacturer of a pressure vessel
- Engineering contractor working for an Owner (Client)
- Authority
- Third party
- Licensed engineer in some countries

differ also per country.

In the majority of countries, however, the owner bears the prime responsibility for the pressure vessel(s) owned or used by him or at his premises; this responsibility covers all aspects such as the correctness of design, the technical state, the legally and technically correct use and the correctness of the documentation belonging to a pressure vessel.

The owner's responsibility is, in some countries, moderated by shifting the responsibility partly to other parties, notably the manufacturer or a qualified and licensed engineer. The first is applicable for e.g. France, the second in the United States - albeit in different ways for the various States - and Thailand.

In the majority of countries the manufacturer bears the prime responsibility for the engineering, design and fabrication aspects of a pressure vessel. Once completed, inspected and accepted by either an authority or a third party and the owner, this responsibility shifts to the owner. There are some exceptions : in France the manufacturer stays responsible for ten years minimum - which means that changes etc. to the pressure vessel require concurrence by the ori­ginal manufacturer! -, in Thailand a licensed engineer, hired for that purpose by the owner, is made responsible (it is not clear whether or not his responsibility covers also occurrences such as unintended use of a pressure vessel and whether it covers all pressure vessels).

The engineering contractor is, in almost all countries, seen as a temporary extension of the owner without an independent responsibility.

Note: the fact that, e.g. in the Netherlands, the engineering contractor can act in a coordinating function (ref. Attachment 1), does not have much effect on his responsibility. This function is limited to a certain project or group of projects and the owner can, at each point in time, withdraw the coordination assignment.

The (pressure vessel) authority is almost always placed in the position of a supervising organization with no direct or indirect responsibility for the pressure vessels supervised. The exception is the Netherlands, where the pressure vessel authority has such a powerful position, that at least an indirect responsibility can be assumed (nevertheless will the prime responsibility stay with the owner).

The third party is normally placed in the position for executing certain or all parts of the assessment, inspection and acceptance of pressure vessels. Although the reports of such a third party are of prime importance for the pressure vessel authority in assessing the issue of e.g. a permit to use a pressure vessels, this does not mean that the third party becomes responsible for that pressure vessel. It is noted in this respect, that the third party can only assess, and thus question, the engineering and design work as presented to him by an owner, an engineering contractor or a manufacturer.

The licensed engineer is positioned in a limited number of coun­tries, in particular those with a legislative system on Anglo-Saxon basis such as Great Britain, the United States of America and Thailand. In these countries, he takes the responsibility for the engineering and design of a pressure vessel, either on behalf of a manufacturer or as part of a legally defined function. The responsibilities are defined in different ways in the various countries and may also vary per state of a federation.

In some countries, such as Thailand, a licensed engineer must be part of an owner's organization as responsible person for the technical state and maintenance work to pressure vessels during their operational life.

4.2 Mandatory and Voluntary Information

4.2.1 Categories of Information

As indicated in 1.0, there are two categories of information, viz.:

- for the installation as a whole, namely information on processing, relations between individual equipment, installation safety etc.
- regarding the individual pressure vessel, namely information on design data, materials, fabrication methods, inspection, testing etc.

The amount of information with respect to each category differs per country.

4.2.2 Information with Regard to Installations as a Whole

Only two of the countries discussed within the scope of this guideline require detailed information regarding an installation as a whole on a mandatory basis, albeit from different view point and via different routes. It concerns:

- the Netherlands, in which country the Pressure Vessel Authority assesses the safety of an installation mainly from the viewpoint of protection against pressures and temperatures outside the limits set by the design; Attachment 1 describes the procedural aspects for this authority, Attachment 2 gives some details about the information.

Note: other hazards than pressures and temperatures outside the limits set by the design are covered via a different assessment system by other authorities.

- Germany, in which country the Pressure Vessel Authority is also the authority which assesses the various aspects of installation safety, including protection against pressures and temperatures outside the limits set by the design; the assessment mechanism (aspects to be considered, documents to be prepared, depth of review etc.) is outside the scope of this guideline.

The authorities in other countries covered by this guide leave the subject to some extent to the responsibility of the Owners line and play a more distant role in the assessment of the safety of installations as a whole. Information given to these authorities is often given on a voluntary basis.

The European Economic Union (EEU) has issued several directives regard­ing overall plant safety in relation to the public and the environment; see ref. 5.10. Several countries have issued additional legislation to cover labor safety aspects, such as the Labor Circumstan­ces Act ("ARBO-wet") in the Netherlands. Pressure vessels, as a source of hazard, are reviewed and discussed within the framework of reports and studies based on such legislation.

4.2.3 Information with Regard to Individual Pressure Vessels

The authorities in the majority of the countries covered by this guideline require, for individual pressure vessels, certain information on a mandatory basis. The information requirements normal­ly focus on:

- construction drawings
- wall thickness and stress calculations
- welding methods and welders' qualifications
- inspection and test methods and their results.

The extent of the mandatory information is often based on the volume and/or the (maximum operating or design) pressure of the vessels or combinations of these, sometimes with the hazardous properties of the contents as auxiliary variable. This leads to the need for classification of the various pressure vessels in an installation; see ref. 5.5 for such classification systematics.

The assessment system is dependent on (1) the classification of a pressure vessel, if a classification system is employed and (2) the legal approach to the supervision of the safety of newly built or extensively (i.e. by a manufacturer and much more than normal maintenance would cover) revamped pressure vessels.

The following two basic approaches of that supervision exist:

- The Owner is the legal responsible party for the majority of his pressure vessels. He determines whether he needs external expertise for, e.g., design assessment or inspection work. There is virtually no legal supervision other than an investigation after a problem (incident or accident) has occurred. The relation between the Owner and the manufacturers is a contractual one only and the manufacturers have no obligations vis-à-vis the authorities.

This approach is followed in Great Britain and Belgium and, for piping systems, in France.

- the Manufacturers are the responsible parties for the pressure vessels designed and manufactured by them and are required to make contact with either the authorities, a third party recognized by the authorities or a licensed engineer to arrange for design assessment and/or inspection work. The Pressure Vessel Authority has the legal supervision over the activities performed by lower authorities, third parties and/or licensed engineers. The relation between the Owner and the manufacturers is a contractual one, but the manufacturers have - directly or indirectly - a separate legal responsibility vis-à-vis the Pressure Vessel Authority.

This approach is followed in Norway, Germany, the Netherlands, France, Switzerland, Portugal, Spain, Italy and Thailand; piping systems are included in Germany, the Netherlands and Portugal.

In the Owner-oriented approach the mandatory information for the Pressure Vessel Authority is relatively minor and often related to the selected design code. The voluntary information is deter­mined by the Owner's requirements.

In the Manufacturer-oriented approach the mandatory information for the Pressure Vessel Authority is usually determined globally by relevant legislation, leaving the details to the lower authorities, the third party or the licensed engineer. This information may then be specified by, e.g., decrees (legal documents), regulations (often privately produced, but generally accepted documents) and an agreement per project or even per pressure vessel. The voluntary information may be defined both by the manufacturers or by the Owners.

Steam boilers and steam vessels fall, in virtually all countries, under a regime that requires involvement of the local Pressure Vessel Authority anyway. The extent of the involvement is, again, different per country and may be even limited to the final hydrostatic test only, leaving the other activities to a recognized third party.

Existing pressure vessels are, when revamped or maintained, supervised in a similar manner, but are under the control of the Owner only (exception : France, as described in 4.1.2).

4.3 Authorities and Third Parties List

4.3.1 List of Authorities and Third Parties per Country

The authorities and third parties can be listed per country, as follows (for abbreviations and notes see below the listing):

Country Pressure Vessel
Netherlands Labor Ministry Stoomwezen
(note 1)
see Attachment 2 for installations
Belgium Labor Ministry see note 2 owner
Germany Gewerbeaufsichtsambt TÜV
(note 3)
France Industry Ministry (see note 4) manufacturer
Her Majesty's
(see note 5) owner
Portugal Industry Ministry (see note 6) manufacturer
Spain Industry Ministry (see note 7) manufacturer
Italy Labor Ministry (see note 8) manufacturer
Switzerland Labor Ministry (see note 9) manufacturer
Norway Labor Ministry (see note 10) manufacturer
Thailand Industry Ministry licensed engineer
(note 11)
or owner


1. this is the only accepted third party in the Netherlands; for non-Dutch manufacturers, this company will decide which local third party will be accepted.

2. recognized third parties for Belgium have been specified in the "Algemeen Reglement voor de Arbeidsbescherming"; non-Belgium manu­facturers have to arrange with the selected third party which local third party may be used.

3. this is the only accepted third party in Germany; for non-Ger­man manufacturers, a specific branch of TÜV will decide which local third party will be accepted.

4. mainly APAVE and Veritas; for non-French manufacturers, the ministry decides which local third parties will be accepted.

5. Great Britain has many companies, which are active in third party assessment and inspection work; for non-British manu­facturers, the Owner can decide which local third party he desires to use.

6. one local organization has been recognized as third party, namely the "Instituto de Soldadura e Qualidade" (ISQ). For non-Portugue­se manufacturers, this institute decides which local third party will be accepted.

7. Spain has many companies, which are active in third party assessment and inspection work; the selection depends on the location and the project and what will be agreed between Owner and authorities. For non-Spanish manufacturers, the selected Spanish third party decides which local third party will be accepted.

8. mainly APAVE Italy, Lloyd's Italy etc.; for non-Italian manufacturers, the local third party should, in principle, be accepted by the authority, but often the Owner will make, for efficiency reasons, his own selection.

9. in Switzerland, the Pressure Vessel Authority operates itself; for non-Swiss manufacturers, a number of locally operating third parties have been accepted.

10. a number of internationally operating third parties have been recognized by the Norwegian Pressure Vessel Authority; the selection may vary per Owner and per project and Owners may be allowed to take the role of 'third party' themselves.

11. the selected licensed engineer may determine which local third parties he will accept; experience has shown, however, that internationally accepted third parties will normally also be accepted in Thailand.


APAVE = Associations de Propriétaire d'Appareils à Vapeur et Électriques
TÜV = Technischer Überwachungs Verein.

4.3.2 Names of Pressure Vessel Authorities

The names of the various Pressure Vessel Authorities are been tabulated below:

Country Name of presssure Vessel Authority
Netherlands Dienst voor het Stoomwezen (abbreviation : DSW)
Belgium Technische Arbeidsinspectie
Germany Gewerbeaufsichtsamt (abbreviation : GAA)
France Direction Regional de l'Industrie et de la Recherche
(abbreviation: DRIR)
Great Britain Her Majesty's Factory Inspectorate
Portugal Direcçôes-Gerais dos Combustiveis e dos Serviços Industriais
Spain Ministry or Department of Industry
Italy Ministerio della Sanita Istituto Superiore per la Prevenzione e la Sicurezza del Lavoro (abbreviation : ISPESL)
Switzerland Schweizerischer Verein für technische Inspektionen (abbreviation in English : SVTI)
Norway Direktoratet for Brann- og Explosjonsvern (abbreviation : DBE)
Thailand Ministry of Industry - for legally established in­dustrial estates the Industrial Estate Authority of Thailand (abbreviation : IEAT) may assume this function.

4.4 Preparation and Submission of Documents

4.4.1 Document Preparation

The need for an engineering contractor to prepare specific documents for a Pressure Vessel Authority depends on the systematics which have been chosen by that authority to fulfil their legal duties. For the countries discussed within the scope of this guideline, there are, consequently, only a few that require such specific documents.

The Pressure Vessel Authorities of other countries may, nevertheless, appreciate to receive such specific documents for information purposes.

4.4.2 Document Types

The documents demanded or often asked for in relation to an installation as a whole include:

- an equipment list (with or without pressure vessel classifications);
- a plot plan showing the equipment locations;
- simplified process description and simplified process flow diagram.

For equipment lists with pressure vessel classifications see ref. 5.5.

The detailed documentation requirements have been specified for the Dutch Pressure Vessel Authority only, because it is one of the most demanding authorities. Reference is made to Attachment 2.

The documents demanded or asked for in relation to individual pressure vessels are globally specified in 4.2.3. A more detailed description is contained in ref. 5.8.

4.4.3 Document Submission

Depending on what has been codified in decrees or regulations or agreed with the relevant Pressure Vessel Authority the document submission for installations as a whole by an engineering contractor can be:

- directly and formal, e.g., for legally required docu­ments provid­ed by the engineering contractor;
- directly but informal, e.g., for documents for information as agreed between authority and engineering contractor;
- indirectly, either formal or informal, e.g., documents delivered via a client.

The document submission by manufacturers should be left to these manufacturers, who have often a permanent relationship with the local Pressure Vessel Authority, the local third party (or third parties) or the licensed eng­ineer(s).

4.5 "New" or "Former" Countries

The knowledge of countries, in which never a project was executed, is usually limited or piecemeal, if available at all. The knowledge of countries, in which a project was executed more than a few years before present, is usually out of date.

In both cases, the requirements for information to be submitted to the Pressure Vessel Authority have to be collected or recollected and/or updated to the latest status. The following routes are normally used to do this:

- review the project documentation available and collect the relevant information;
- make contact with the client and collect his information and/or request to provide for a first contact between Pressure Vessel Authority and engineering contractor;
- contact the Pressure Vessel Authority or a (or the) local third party resp. licensed engineer and collect their information and/ or agree upon, e.g.:

  • the mandatory information
  • the voluntary information
  • classification systematics if unknown or unclear
  • submission and approval systematics
  • contacts and correspondence.

As a last resource, the local manufacturers can be contacted for the desired information.

The following should be noted:

- local manufacturers have sometimes, as a result of long term relationships, access to information which is nor­mally not directly available to outsiders and they may be aware of 'short­cutting' methods to obtain certain approvals;

- large countries such as Germany and France have a large number of regional or local offices, which - although part of the same Authority or third party - may have different approaches to the subject matter; this should be recognized timely and used to the benefit of the project;

- licensed engineers may have an individual approach to the matter, which could be beneficial to the project.

The value of local inputs increases with increasing cultural and linguistic differences between the country of the engineering contractor and the country, where the project should be realized.

5. References


  Number Title Level
5.1 BN-EP-060 Invoices from Stoomwezen 3
5.2 BN-EG-UE204 Preparation of Classification Lists
for Pressure Vessel Authorities
5.3 BN-EG-UE205 Preparation of the Pump List 5
5.4 BN-EG-UE206 The "Nader Onderzoek" 5
5.5 BN-EG-UE214

Preparation of Equipment Classification Lists for the Dutch Pressure Vessel Authority

5.6 BN-EG-UE215 Pressure Vessel Definitions and Related
Authority Requirements (later)
5.7 BN-EG-UE216 Practical Hints for the Preparation of Hazard
Category Calculations (later)
5.8 BN-EG-(later) Handling of Individual Pressure Vessels Subject
to Assessment and Inspection by Stoomwezen B.V.
5.9 84/525/EEG Council Directive on the Approximation of the Laws of the Member States Regarding to Seamless, Steel Gas Cylinders (similar are 84/526/EEG and 84/527/EEG) -
5.10 82/501/EEG Council Directive on the Hazards of Severe Accidents During Certain Industrial Activities (changed by 87/216/EEG and 88/610/EEG) -

Some of the above references are only used for the Attachments to this guide; additionally, the Attachments have their own list of specific references to non-Company documents.

6. Attachments

1. Procedural Information for Relation with the Dutch Pressure Vessel Authority (Stoomwezen B.V.)

2. Information to be Submitted to the Dutch Pressure Vessel Author­ity (Stoomwezen B.V.).

Procedural Information for Relation with the Dutch Pressure Vessel Authority

(Stoomwezen B.V.)

1. Introduction

1.1 References

References to Company documents are only listed in the Reference section of the main text of this guideline; they are numbered consecut­ively 5.1 and up.

References to certain Stoomwezen B.V. regulations have been listed in section 6.0 of this Attachment and are numbered a,b etc.

1.2 Basis of Attachment

The basis for this attachment is section 'G' of the Stoomwezen B.V. regulations, which describe the procedures, main working methods, stan­dards and regulations applied by Stoomwezen B.V. regarding material, construction, fabrication, inspection, testing and use of pressure vessels and their appurtenances. See ref. a.

The regulations are commonly described as "Rules for Pressure Vessels" or simpler "Rules".

1.3 Status of the Stoomwezen B.V. Regulations

The Stoomwezen B.V. regulations should be considered as published guid­ing principles that underlie the assessment of pressure vessels by Stoomwezen B.V., except where these regulations are explicitly intended to fulfil a compliance requirement imposed by the (Dutch) legislation. See ref. a.

In practice this means, that:

(1) certain requirements specified in the "Rules" can be discussed with Stoomwezen B.V.

(2) certain requirements may be modified by mutual agreement or by decision of Stoomwezen B.V.

(3) additional requirements may be formulated during the assessment and inspection work.

2. Definitions

2.1 Steam Act

The Act of 25 March, 1953, amended by the Act of 28 November 1979, regulating the supervision of the use of steam and vapor apparatus. The text is contained in ref. c.

2.2 Steam Decree

The Decree of 22 December, 1953, amended by the Decrees of 4 December, 1980 and 5 June, 1990, establishing a general administrative order for the implemen­tation of Sections 2, 3, 4, 6, 11 (subsection 3 only) and 21 of the Steam Act. The text is contained in ref. d.

2.3 The Interested Party

The interested party is the party that wants to use one or more pressure vessels and has, consequently, interest in having these assessed and inspected by Stoomwezen B.V. to the extent required by the Steam Act or his operating/environmental permit. In Company terms it is usually the Client.

Note: this definition is not contained in the "Rules".

2.4 Project

A whole of interrelated activities in connection with the construction, extension or modification of one or more installations.

This is the definition used by Stoomwezen B.V., which deviates from the definition currently used by Company. The Stoom­wezen B.V. based definition is used throughout this Attachment.

2.5 Main Procedure

The Main Procedure is that part of the procedure for handling pressure vessels that relates to establishing the operating conditions of the various pressure vessels in an installation.

This therefore also includes the influence of the installation on those operating conditions and accordingly the safety analysis mentioned in 4.8.

For handling individual pressure vessels reference is made to ref. 5.8.


1. "Operating conditions" are, in this Attachment, the maximum possible operating pressures and temperatures, or the most severe combination(s) of possible operating pressures and temperatures.

2. Pressure vessels do, according to the "Rules", include piping systems.

2.6 Coordinator

A person or body (belonging to an organization established in the Netherlands) who has the task (and possesses the expertise to per­form that task) of maintaining contacts with Stoomwezen B.V. on behalf of the interested party on a project and performing all the tasks described in section 4.4 of this Attachment.

This definition implies that an expert interested party can also act as Coordinator. For Company, the Coordinator will normally be selected from the Authority Engineering group.

2.7 Pressure Vessel

The meaning of the concept 'Pressure Vessel' has been detailed in ref. 5.6.

2.8 Other Definitions

Other definitions in relation to the "Rules" can be found in ref. b.

3. Responsibilities

The interested party is responsible for announcement of the project to Stoomwezen B.V., for assignment of an organization as Coordinator and for indicating whether or not certain arrangements need to be made.

The Coordinator has the overall responsibility for the checking of the documents to be submitted to Stoomwezen and for all contacts with the responsible Stoomwezen office.

The office of Stoomwezen B.V., which has the jurisdiction over the area in which the project will be executed, has the overall responsibility for the assessment of the documents submitted to them and for the administrative and technical activities required by the "Rules".

4. Procedural Aspects

4.1 Introduction

This section is largely a summary of ref. f, supplemented by notes and remarks applicable for Company.

4.2 Project Announcement

The interested party should announce the project in writing to the Stoomwezen office, which has the jurisdiction over the area in which the project will be executed. With the announcement, the interested party should include information regarding:

- the applicability of the Main procedure systematics as described in ref. f. (note : it is possible not to apply these systematics, however, at the risk of the interested party);
- the organization(s), which would perform the Coordination tasks;
- the individual name(s) of the Coordinator(s) if already assigned;
- the preliminary project schedule;
- a first estimate of the number and type of pressure vessels (inclusive of piping systems) involved in the project.

4.3 Appointment of Coordinator

The interested party should appoint a Coordinator, either a person or an organization; an organization should, in turn, appoint the responsible individual.

The Coordinator should be the same organization for the entire project, except in those cases where very large projects are divided over several engineering contractors or where several coordinators will be needed for contractual or practical reasons. Within the same organi­zation the activities may be (re)delegated to more than one person, with only one person as responsible vis-à-vis Stoomwezen B.V.

Such arrangements should be clearly communicated to Stoomwezen B.V. to enable them to assign personnel and to plan for the most efficient approach of handling and administration.

Note: in practice this means, that projects that are partially executed by a certain organization should be identified as such by name and/or number. Examples are projects which consist of both new construction/revamp plus a maintenance turnaround (which in itself may comprise repair, minor new construction and revamp work), where the coordination should be divided over the organization responsible for the new construction and revamp work and the organization handling the maintenance turnover.

4.4 Tasks of Coordinator

The Coordinator should check all documents to be submitted to Stoomwezen B.V. and all the data contained in the documents.

This check should at least comprise the completeness of the documents and the data and their concurrence with the classific­ation list (see ref. 5.5). The Coordinator - as a person or an organization - is not held responsible for the correctness of each single piece of information.

For document preparation aspects see Attachment 2 and ref. 5.5.

4.5 Responsible Stoomwezen Office

Stoomwezen B.V. should stipulate which office is responsible for the Main procedure. Normally this is the district office with jurisdiction over the area in which the plant has been or will be built.

Typical aspects of the Stoomwezen office's tasks are:

- assessment of the documents submitted to them by the Coordinator; for the listing of documents and information see Attachment 2;
- the technical activities required by the "Rules" such as inspection and checking in and outside the Netherlands and the so-called "Nader Onderzoek" (see ref. 5.4 and 5.8);
- the administrative activities required by the "Rules", inclusive of obtaining information from or sending information to other Stoomwezen offices, assigning registration and sequence numbers, preparation of certificates of inspection and testing (the so-called BOB's), advising on operation permits to be issued etc.

4.6 Communications

All communications should normally be in writing. All written contacts regarding the Main procedure should be between the Coordinator and the office mentioned under 4.5. Verbal arrangements other than minor practical points should be confirmed in writing.

Dutch manufacturers should communicate, for the equipment items designed and/or manufactured by them, directly with the Stoomwezen B.V. office, which has the jurisdiction in their area. For non-Dutch manufacturers different rules apply; see ref. 5.8 and ref. e.

The communications such as letters, telexes, fares, and any verbal contacts with Stoomwezen B.V. should be in the Dutch language.

4.7 Documents

Documents such as drawings, specifications, calculations, procedures, certifi­cates and minutes of meeting may be submitted in another language, preferably in English, German or French. Other languages such as Italian, Spanish, Romanian and others should be accompanied by a translation in English.

The units used in the documents should be in agreement with ref. b. The symbols should by preference in agreement with ref. b, but other symbols are often accepted if clear and/or clearly explained.

Note: this may be important for computerized calculations.

4.8 Assessment Systematics

In assessing a pressure vessel Stoomwezen B.V. also considers the influence that the parts of the installation connected to it exert on the operating conditions of that pressure vessel. This influence is established in principle when the pressure vessel has been erected and is almost ready for operation. For steam and vapor apparatuses this is done as part of the 'final examination after installation', the so-called "Nader Onderzoek" (see ref. 5.4).

For simple installations where the influence is easy to survey, such an examination in the 'ready for operation' condition will suffice.

In complex installations the influence of other parts of the installation on the pressure vessel is more difficult to determine. As a result the required examination is much more extensive than for simple installations and is may be more like a safety analysis. If, in com­plex installations, the examination would be performed only in the 'ready for operation' condition, an increased and unpredictable risk of difficulties may be assumed.

To obviate the related risks of considerable changes, delays, etc., it is strongly recommended that the influence of the pressure vessels on each other be subjected to assessment by Stoomwezen at an early stage. The assessment is primarily based on the documents submitted for assessment and/or information as well as the findings during the design and manufacturing work for equipment and piping.

With a successful assessment procedure, the examination in the 'ready for operation' condi­tion can then be confined to the set-up and lay-out and to a check on agreement between the assessed and executed condition (see ref. 5.4).

For more information see ref. 5.5, ref. g and Attachment 2 of this guideline.

5. Flowchart



6. References for This Attachment








Introduction (to ‘Rules for Pressure Vessels’)




Definitios, Quantities, Units and Symbols




Steam Act 1953




Steam Decree 1953




General Procedures




Procedures for Pressure Vessels in Installations




Classification of Pressure Vessels


Information to be submitted to the Dutch Pressure Vessel Authority
(Stoomwezen B.V.)

1. Introduction

The information to be submitted to Stoomwezen B.V. for projects executed in the Netherlands is defined on basis of the Steam Act, the Steam Decree and the subsequently developed internal rules of Stoomwezen. These "Rules for Pressure Vessels" or shortly "Rules" are published for information of manufacturers and users of boilers and pressure vessels. Compliance with them is, except for steam and vapor boilers and steam and vapor vessels subject to the Steam Decree, not mandatory, but simplifies the approval cycle.

The paragraphs below describe the information to be submitted to Stoom­wezen B.V. for projects executed in the Netherlands.

Note: Stoomwezen B.V. has become a private company as of 1 June, 1994; although the "Rules" have not been adapted to this situation at the same point in time, there may be changes expected in future in order to comply with the private status and to comply with forthcoming European regulations.

For the financial aspects of the relations with Stoomwezen B.V. and the Dienst voor het Stoomwezen (the Dutch Pressure Vessel Authority) reference is made to ref. 5.1.

2. General

2.1 Formal Requirements

For a description of the formal requirements reference is made to Attachment 1, which covers definitions, a number of responsibilities for and a description of the main procedure aspects.

2.2 References

References to Company documents are only listed in the Reference section of the main text of this guideline; they are numbered consecutively 5.1 and up.

References to certain Stoomwezen B.V. regulations have been listed in section 5.0 of this Attachment and are numbered a,b etc.

3. Responsibilities

The assigned Authority Engineer acts as Coordinator and has the overall responsibility for the checking of the documents to be submitted to Stoomwezen B.V. and for all contacts with the responsible Stoomwezen B.V. office.

The various engineering Departments and Groups have the responsibility for the preparation of the documents for which they are responsible in the Company organization and to support the coordinator in his contacts with Stoomwezen B.V.

4. Guidelines

4.1 Preparation of Documents and Supply of Data

The following engineering Departments and Groups should prepare the documents listed under their responsibility and/or provide the necessary information:

Process Department/process group:  
- Process description - see 4.2.1 below
- Material balance - see 4.2.5 below
- Pressure Protection Survey
(except capacity calculation)
- see 4.2.7 below
Process Department/systems group:  
- Line tables
(in concert with process group)
- see 4.2.3 below
- P&I diagrams - see 4.2.2 below
(in concert with process and Control Systems groups)  
Engineering Department/project group:  
- Classification list
(in concert with process group)
- see 4.2.1 below
- Pump list
(in concert with process group)
- see 4.2.8 below
Engineering Department/Control Systems group:  
- Pressure protection
capacity calculations
- see 4.2.7 below
Engineering Department/Authority group:  
- Hazard category calculation(s) - see 4.2.6 below.

4.2 Minimum Required Data

The minimum required data for the Main procedure of Stoomwezen B.V. are specified in ref. a and listed below.

4.2.1 Fully completed classification lists in accordance ref. b; for a detailed description of the classification list see ref. 5.5.

4.2.2 One or more diagrams containing all the following data in clear fashion:

- designation and identification of all pressure vessels (including lines) that occur in the classification lists;

- designation and identification of all other pressure vessels (including piping) and other parts of the installation that may exert an influence on the operating conditions of the pressure vessels mentioned in the previous point;

Note: this, consequently, includes items such as furnaces, ejectors, electrical heaters.

- designation and identification of appurtenances.
For pressure safety devices the set pressure or bursting pressure and the discharge pipe, if present, must be indicated. Appurtenances also include mechanical safety devices such as interlocked valves;

- a clear indication of the interrelation of all the pressure vessels stated, including lines and appurtenances;

- designation and identification of pumps, compressors, other rotating equipment and machinery;

- location, function and area of influence of measurement and control systems that may influence the operating conditions of the pressure vessels.


  1. The above information is, for the projects executed normally by Company, contained in the P&I Diagrams.
  2. The drafting of separate diagrams with a summarizing function is normally not necessary for Stoomwezen B.V. (except for very complex piping systems).

4.2.3 Fully completed line tables.
Although not separately mentioned in the "Rules", this document is required (a) to establish which piping systems will require a license, (b) to assess the design conditions and (c) to establish for which piping systems an assessment per condition of the environmental permit will be required (see also 4.2.9).

4.2.4 A description of the process containing the main data on the course and control of the process.

4.2.5 A material balance covering all main streams; this document is required for checking the hazard category calculation(s) of 4.2.5.

4.2.6 A hazard category calculation; for a number of practical hints see ref. 5.7.

4.2.7 A survey of the appurtenances for pressure protection stating type (safety valve, bursting disc), set pressure or bursting pressure, complete with capacity calculations and indication of the provisions for the safe discharge of substances blown off.

4.2.8 A survey of pumps, compressors etc., stating the type (centrifugal, reciprocating), the drive (electrical or otherwise) and the maximum differential pressure; for a detailed description see ref. 5.3.
This document is required to establish design pressures and/or the necessity of pressure protection devices in pumped circuits.

4.2.9 In addition to the above Stoomwezen may request:

- a copy of the existing environmental permit inclusive of its conditions, unless such copy has been sent in the past and the permit has not been changed since, and/or
- a copy of the environmental permit application issued for the project, inclusive of the decision of the responsible authorities.

4.2.10 Supplementary Data

Stoomwezen B.V. may, depending on the project's nature and complexity, demand supplementary data for the assessment work, for example logic diagrams.

For the "Nader onderzoek" of the installation, which should be executed as part of the main procedure at the end of it, Stoomwezen B.V. will ask for supplementary data and/or information regarding (1) test curves of pumps and compressors and (2) measuring certificates ("meetbrieven") of safety valves. See ref. 5.4.

References for This Attachment








Procedures for Pressure Vessels in Installations




Classification of Pressure Vessels