Proven People, Products & Performance Revalidation Issues Surrounding Cryogenic Storage Tanks Cryo Ops 2014 Paul Rowe Wessington Cryogenics

Proven People, Products & Performance

Revalidation Issues Surrounding Cryogenic Storage Tanks

Cryo Ops 2014

Paul RoweWessington Cryogenics


UK / Overseas?

• This is based on several years discussions with UK Gas Suppliers, Health & Safety Executive, UK Insurers and the British Compressed Gases Association (BCGA)

• It is now also being discussed within European Industrial Gases Association (EIGA) so potentially has wider implications / scope for users of cryogenic tanks

• UK Gas suppliers are Global Gas Suppliers!


Background• Pressure Systems Safety Regulations 2000 (PSSR)• British Compressed Gases Association Codes of

Practice :• CP25-Revalidation of Cryogenic Static Storage Tanks• TIS 23 – Internal Examination of Cryogenic Tanks• GN17 - BCGA Policy and guidance for the safe filling of third-

party owned and / or maintained tanks• CP39 Mod 1-In-service Requirements of Cryogenic Storage

Systems at User Premises

• Company Insurance• 3rd Party Independent Inspection Authority• Health & Safety Executive


PSSR & WPSE

• Legal requirement to develop a written periodic scheme of examination for all pressure vessels.

• Mandatory in the UK since 1989 via previous legislation / 2000 in current form

• Competent person must be satisfied that the vessel is fit for purpose and safe to operate at the designated operating conditions – not just the fact that ‘its always been like that’


BCGA CP25• Code of Practice – not statute. However, if something

goes wrong, expect the HSE to ask why you were not following best practice! ‘No Win, No Fee’ solicitors may ask some awkward questions!

• BCGA Codes of Practice are adhered to by all the major UK gas supply companies and more and more insurance companies are becoming aware of them

• Good, sound engineering advice intended to keep the user of such equipment safe.

• Scope originally aimed at bulk static / fixed tanks. This was removed and essentially should cover all vessels


Scope of CP25• To provide guidelines for the periodic examination of

cryogenic tanks which can be incorporated into either Written Schemes of Examination under PSSR , or company maintenance and examination records

• Covers the revalidation of static tanks specifically designed for the purpose of storing cryogenic liquid– No volume criteria is given!– No pressure criteria is given!– No definition of ‘Static’ is given!

• CP25 remains valid, but will become obsolete with the full publication of CP39 and all modules, plus various other Codes of Practice – replaced by TIS 23


Technical Information Sheet TIS23• For tanks designed, manufactured and inspected in

accordance with a recognised code, operated and maintained for cryogenic service, with the absence of failure mechanisms outlined, the probability of failure is extremely low.

• This is a clear statement supporting the industry conclusion that correctly designed, constructed, approved, operated and maintained cryogenic tanks do not deteriorate in service and therefore internal examination and proof pressure testing are not required.

• The BCGA will continue to collate the results of inner vessel examinations in support of this policy for static tanks and update the data tables in Appendix 1 on a periodic basis.


Technical Information Sheet TIS23• Policy regarding internal examination and proof pressure

testing of static cryogenic liquid storage tanks• A BCGA / Gas company response to HSE requests that

there should be a means of internal examinations of cryogenic tanks

• Notable by their absence are reference to dewars and vessels! All the supporting evidence is solely bulk, stationary storage tanks!

• Have you ever had a small mobile vessel / dewar that needed an internal repair?


Guidance Note GN-17

• This document defines a gas supplier’s responsibilities when intending to fill a third party owned tank, used for the storage of refrigerated liquefied gases (typically nitrogen, oxygen, argon and carbon dioxide) at a customer’s premises.

• BCGA Policy is that no Member shall fill a tank until it has established that it is safe


First fill

• The gas company will :-– Full set of physical checks on the vessel, the

area, vessel documentation etc– Check customer understands his

responsibilities under PSSR– Customer understands operation of vessel

and how to report any changes


Subsequent Fills

• The gas company will :-– Undertake such checks as they deem reasonable to

ensure that the tank remains safe to fill– Review any reported problems– Require the customer to take prompt action if the tank

is in breach of PSSR and take action to make safe– Check the vessel has been revalidated if >20 years

old– Potentially suspend deliveries


CP39 Module 1

• Scope :-– Covers the in service requirements of

cryogenic storage systems of :-• Storage tank• Vaporiser• Control manifold• Interconnecting pipe work


Revalidation to CP39 Mod 1• The revalidation of a tank as fit for continued

service shall be based upon periodic reviews of documentation carried out by the Competent Person.

• The revalidation process shall comprise the following steps :-


Revalidation• Review of design documentation• Review of service history records(incl. all

pressure excursions)• Review of external examination records• Review of experience of similar tanks• Confirmation that an APEA has been carried out• Preparation of revalidation report


Ageing Pressure Equipment Assessment

• An appropriate APEA should be completed by the Competent Person prior to putting the system into service

• Prior to the WPSE, it is essential to consider the effect of ageing on the pressure equipment


Documentation & Records

• New equipment to comply with PER & shall have all appropriate documentation retained for life

• Old equipment shall have the documentation as required by the applicable regulations at time of manufacture

• All of the above shall be available to the competent person to produce / complete WPSE

• Where not available, the competent person may require that a process of revalidation be undertaken prior to confirming suitability of the equipment for continued service – which process? CP25?


Deficiencies

• Any deficiencies identified in the reviews of design, service history or examination records shall be assessed by the Competent Person.

• Any deficiencies and the conclusion of the assessment shall be recorded in the revalidation record


Supporting Information• Where the original tank construction dossier or service /

examination records are incomplete the Competent Person shall decide upon the appropriate action required to revalidate the tank.

• Complete and original construction drawings in conjunction with information from the tank nameplate may suffice where full construction dossiers are unavailable

• In extreme cases an internal examination of the tank, or of a similar tank, may be necessary to establish base line data for this and future revalidations – cost effective?


Frequency of Revalidation• The frequency of revalidation shall be decided by the

Competent Person but shall not be less than once in 20 years

• Remember, 20 years was referenced for bulk static tanks! Consideration should be given for reduced frequency for mobile vessels.

• Wessington’s own guidance is that the frequency should reduce to 5 years after this initial period (for ADR road transport tanks, from new, a full inspection is required every 5 years!)


Example vessel currently at Wessington awaiting repair


Typical Vessel

• 160 litre, 3 bar self pressuring liquid nitrogen vessel

• Manufactured ‘?’ years ago (unknown!)• User does not have original design dossier / test

certificate / drawings• Minimal information available on the vessel data

plate– Ie no design code stated, MAWP / design pressure

info, temperature


Referring to that specific vessel…

• Comment from 3rd party independent inspection engineer from Lloyds, employed by Wessington to review our new build tanks :-– “I wouldn’t touch it with a bargepole!”


General Comment from HSE

• Comment from Health & Safety Executive pressure vessel expert :-– “Do not use the vessel until it has been fully

revalidated / I expect to see a comprehensive data plate & test certificate”


Previous Vessels Are No Better!

No dossier!No data plate!No drawings!No operating instructions!

Nothing to work from!


What Next?• If you have such equipment in operation, you need to

ensure that your insurance company is aware of the vessels, and that they have all the relevant test certificates / vessel dossier.

• Is the data plate in good condition / legible?• Can you really revalidate the tank based on the

information available to you?• Gas companies are aware of this and are increasingly

pushing this issue


What next?

• Wessington have to take a pragmatic stance – although we are prepared to repair any manufacturer’s cryogenic pressure vessel, we see it as only right to follow all the current rules, regulations, codes of practice, gas company internal interpretations of rules, comments from 3rd party engineers and the HSE

• We will not be repairing vessels what our own 3rd party inspectors say they would not touch with a bargepole!!

• Should you or anyone else?!


Thank You

Paul RoweWessington Cryogenics

Documents

Proven People, Products & Performance Revalidation Issues Surrounding Cryogenic Storage Tanks Cryo Ops 2014 Paul Rowe Wessington Cryogenics