Read Challenges in Complying with EN 13121 Specification text version


Presented By: Eli Levy, PrEng. For Composites Africa 2009


The BS 4994 : 1987 has been used in South Africa for many years by the Chemical and petrochemical industry for the manufacture of tanks and pressure vessels in GRP, for corrosive and hazardous applications. The industry has been used to this standard which has proven successful and many equipment items exist in this country and in Southern Africa designed and manufactured in accordance with the BS standard.


The European Community has decided to declare obsolescent BS 4994 : 1987 as of 31 December 2009 and have it replaced with the European norm BS EN 13121-3. This new standard is composed of four sections, namely BS EN 13121-3 Part 1, BS EN 13121-3 Part 2, BS EN 13121-3 Part 3 and BS EN 13121-3 Part 4. After several drafts issued since 2004 on Part 3, GRP tanks and vessels for use above ground - Design and workmanship, the final issue of this standard was issued in 2008 as BS EN 13121 ­ 3 : 2008.

The local industry found that this new standard had numerous typing errors and substantial differences in comparison with BS 4994 : 1987. Application of the new standard could lead to errors in manufacture and compromise the integrity of equipment manufactured in accordance with this standard. In addition, there was a requirement from SABS to adopt BS EN 1312 in all four parts as a standard document and give a SANS number to these documents.


A Technical Committee was appointed to study this international standard and recommend the adoption of the BS EN 13121 Standard as a national Standard document. This Committee was tasked to make recommendations to the South African Bureau of Standards (SABS) in order to adopt this document as South African National Standards (SANS 53121) in all 4 parts. At a Technical Committee meeting, a list of exceptions was prepared and sent to the International (European) Technical committee for review and if these corrections were found justified, for correction of the European standard.

The Committee agreed at the meeting that the local industry is very keen and desirous to adopt this standard and work at the same standard as the international (European) standards, in order to ensure that the trade between South Africa and Europe is continued. South Africa has very strong links with Companies and manufacturers of GRP equipment in Germany, UK, France and other European countries and ensuring the same standards is imperative to the continuing trade and for our benefit to ensure the exchange of knowledge and technology with other counterparts in Europe.


Knowledge and awareness of these inaccuracies and ambiguities is crucial to the industry in order to understand the differences between the two codes and to ensure that integrity of the manufactured equipment is maintained.


· · · · · · · Standard Design Technical Committee Adoption Implementation Competitiveness Excellence



Our Technical Committee was tasked to make recommendations to the South African Bureau of Standards (SABS) to adopt this document as South African National Standards (SANS 53121) in all 4 parts. This committee also will be disbanded once the recommendation has been made.

On the 25 February this year, the Technical Committee had a meeting in Durban in which the BS EN 13121 standards were reviewed from the technical aspect. The committee considered making the recommendation to SABS for adoption of these documents, but it was found that Part 3 : Design and Workmanship, had numerous typing errors and substantial differences in comparison with BS 4994 : 1987.

Although a decision in principle was taken that the adoption of BS EN 13121 Parts 1 to 4 would be beneficial and shall be recommended, the Committee was unanimous in deciding that at the same time, we as a technical committee shall refer back to the European Committee and inform the Secretary of the technical committee responsible of these inaccuracies and ambiguities that the technical committee has found in their review of this standard (Part 3).

We also noticed at the back of this standard, that there is provision for users of the British Standard documents to refer back to the British Standards Institution (BSI) and inform the Secretary of these findings.

We have tried to make contact with several bodies in Europe and our attempts have been unsuccessful. More recently, the British Standard Institute (BSI) has shown a keen interest in speaking to the UK convenor of CEN/TC210/WG2 and try to discuss this important issue so that the "errors" can be addressed by a new forum and if these are indeed errors, to have them corrected for the benefit of the users and the Standards Institutions around the world using this standard.

The findings of the Technical Committee were sent by e-mail in native format (Word and Excel) with the tabulation prepared listing the apparent errors found in BS EN 13121 : 2008 to the BSI for further action.

We believe that the rectification of the Standard and adoption by SANS are fundamental elements in order for the local industry to implement this standard.

Because the BS 4994 : 1987 remains current but will be declared obsolescent as of 31 December 2009, it is essential that this issue be resolved long prior to that time, such that the local industry will have ample time for the transition from one BS standard to the new standard, before implementation of EN 13121-3 : 2008 in Europe.

SABS BS 4994 : 1987 STANDARD

This standard is an adoption of BS 4994 : 1987 and it has been used in South Africa for the design an construction of vessels and tanks in reinforced plastics for many years.


The UK has adopted the European Standard BS EN 13121: 2008. The final part Part 3 has been published. Therefore, BS 4994 : 1987 Specification for design and construction of vessels and tanks in reinforced plastics has been declared obsolescent on the 31 December 2009. This Standard will still cover those tanks still in service made from GRP which are generally accepted and have a long working life.


This Standard is in four parts, namely: EN 13121 ­ GRP tanks and vessels for use above ground · Part 1 ­ Raw Materials ­ Specification conditions and acceptance conditions · Part 2 ­ Composite materials ­ Chemical resistance · Part 3 ­ Design and workmanship · Part 4 ­ Delivery, Installation and maintenance


Following the meeting in Durban, a comprehensive list including Fibre-Wound and Amitech comments of errors was compiled by Eli Levy as Chairman of the Committee. This list was sent to working group members for comments and subsequently to SABS on 6 April 2009. SABS has communicated this list to the CEN contact person and the Committee are waiting for the CEN committee to re-open work on EN 13121 Part 3 and address these apparent errors in document.

The main comments are the Scope of BS EN 13121 : 2008 Part 3, which limits the pressure for Pressurized equipment to 10 bar (1000 kPa) and the Heat Deflection Temperature (HDT) of the resin which is HDT > TS +40 deg.C (40 deg.C above design temperature) of the equipment. There is a Global format for batch certificate of analysis for resin currently in progress in Europe ­ including tests and methods to be done. Proposals have been submitted but this is not yet finalised.

Other comments are typographical errors in formulas which invalidate the calculations if used and other typing errors due to the font used in BS EN 13121 : 2008 Part 3, as well as errors in Figures and in various equations. In the interim, approval from the DoL needs to be obtained with a short list to ensure that the use of this new standard will still be part of the legal process. Exceptions to BS EN 13121 : 2008 Part 3 from DoL will only be applicable in South Africa.

Examples are: ·Exemption required on the use of the formulas ·Errors in Formulas to Engineering Practice ­ What is the risk and how many? ·Typo's can cause design issues ·Allow industry to use local conditions incorporating SA manufacturer & materials of use as currently in BS 4994 : 1987 ·Standard configurations, e.g. shapes ­ Number ·Materials (liner material) ­ strength

PCISA will communicate it to the industry ­ manufacturer to evaluate this list and confirm that they agree with this before manufacture.

The HDT issue still needs to be resolved, specifically for equipment used at high temperature (80 deg. C and above) in dry Chlorine service. Note that in ISO 14692 it is Design Temp = HDT-20degC


A Chlorine Drying Tower was made for Sasol by Uhde with design to BS 4994 : 1987 and fabricated in Germany to strict requirements. The Design Code was BS 4994 : 1987 and EN 13121 Parts 1, 2 and 4.


The local industry has successfully applied the BS 4994 : 1987 standard for many years and achieved a high degree of excellence in the design and manufacturing of vessels and tanks in reinforced plastics. With the withdrawal of this standard in Europe and the need to maintain this international level of standards, it will be a challenge to the industry to ensure that in future equipment is

designed, fabricated, inspected, tested and installed successfully in GRP in accordance with BS EN 13121 Parts 1 to 4. This must include Part 3. A rigorous standard of design and fabrication will have to be maintained in order to ensure that designers and manufacturers are still competitive in Germany and Europe and can compete at international level of achievement.


Eli Levy, PrEng

Engineer: Principal Mechanical UHDE - a division of ThyssenKrupp Engineering (Pty) Ltd P.O.Box 1636, Gallo Manor, 2052 - South Africa

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Tel: +27 11 236 1385 Fax: +27 11 236 1079 Cell: 082-459-5517 E-mail: [email protected] Website:


Challenges in Complying with EN 13121 Specification

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