Australian Pressure Equipment Knowledge

 by Stan Ambrose, Australian Institute for Certification of Inspection Personnel, Sydney, AU

  for Chinese PV Conference, Hefei 21/10/2017

 

Abstract:   A number of cases of successful introduction of new PE technology are reviewed - the main one being a completely new design of beer barrel which caused much resistance from many businesses, as well as government and unions.  These real cases, dating from 1980s to this year, are used to propose a number of key principles or practices to gain the benefits of sound technology, and in the beer barrel case inadvertently save about 20 lives and many back injuries and $millions.

 

(Note. Technology here is taken to include science.)

  Starting thousands of years ago, technology began to accelerate about the time of Newton, then with the steam-age using boilers continued into the 20th century with a huge boost in PV and other new technologies.

In the 1950s, Nehru in India and in December 1978 after the “Cultural Revolution” Deng Xiaoping the new leader of China, started to advance their countries with the help of technology. Huge gains resulted rapidly.

(As a result of inter-government agreement, Stan was sent to China in 1986 for 8 days to help. His 1st of many welcomes, in Guangzhou (Canton) was: “Did you have a nice fright”. He rapidly learnt language could be a problem but not friendship. His last trip in 11/2017 with much help from Greg confirmed the expected huge advances that had been made overall. eg push bikes on crowded roads completely replaced by cars newer than his, by electric bikes and freeways. Max. speed of the train to Hefei was 307 kph, buildings had greatly increased, become modern and grown taller)

  However new technology, like many things, has both benefits and disadvantages and problems. These can range from huge to trivial for our universe, society, the Earth and all businesses - private, large, medium and small enterprises, and governments in all countries, and involving all types of industries.

  Its new problems arise from our natural resistance to change - fear of unknown, risk of failure, is it true and competition) and our inability to predict all important future outcomes. Another cause of these problems can be the difficulty of communication, understanding, trust and reaching agreement on change between technologists (engineers, scientists and other technologists) and business, people and government people eg facetiously Putt’s law says:

  “Technology is dominated by two types of people - 

those who manage what they do not understand.”   (Similarly it can be said about business)

  For humanity to continue and improve we need to adequately manage these issues. FIG 1 clearly shows how the huge benefits and problems from PE technology (and very similarly with road vehicle technology) have changed for the good over 2 centuries.   Technology, prediction and controls initially were inadequate. Then, many failures severely impacted on people and business.  R&D, education, laws, standards, feedback and cooperation have resulte d in humans making continual improvement

d in humans making continual improvement.

 

 Notes 1. Lloyds Register; ASME 1; Hilliers Rules, etc. etc. 

2. AS CBI-V 1952:  max: WJF = 0.95; SF = 4 

3. AS CB1-V Amdt:  max: WJF = 1.00; SF = 4  

4. AS 1228 max: WJF = 1.00 SF = 2.7 

5. AS 1210 Supplement No 1:  SF = 2.35 below creep range  

5a AS 1210 Supplement No 2:  SF = 2.25 with stainless steels and no corrosion 

6. Probable future trend - design for all modes of failure covered specifically 

7. Seat belt availability + law 

8. Breath testing + law 

9. Divided highways (plus publicity, policing, improved roads, cars, airbags etc) 

10. The three drops are due to new technology plus enforced and improved laws taking

service inspection)  

millions. 

  FIG 1    IMPACT OF TECHNOLOGY, LAW, STANDARDS AND HUMANS

 

 2 PURPOSE   This paper primarily aims to help the continued improvement of PV technology by passing on some knowledge and principles gained from a few real cases over many years, mainly in AU but also internationally. These show the main problems which arise in introducing new PV technology, their complexity, the various resistances that arise from business or non-technical factors, their impact, the solutions reached, omissions made, and overall benefits.

 

3 MAIN CASE 1 - BEER BARRELS  (BB)  

.1  Coverage   This Case:

a) Deals with the replacement of wooden and similar SS barrels by modern stainless steel (SS) types as in Fig 2, in the early 1980s in AU;

  b) covers nearly all major factors in successfully introducing any new technology and its impacts

on various businesses and people ; and

c) as far as can be recalled, outlines main details in time-sequence.

.2 Initial Stages

a) The GM of a big brewery liked a completely new design BB at an overseas trade exhibition. It was smaller, cheaper, lighter, safer and easier to handle than those currently made and used in AU.

b) The Chief Engineer (CE) informed GM that he did not think it would meet AU Standards and hence State regulations (the first of many resistances); and so he was asked to find out.

c) The CE discussed with an AU PV Safety Regulator (CIB) their desire to use imported barrels of a completely new design, at least initially – even though the design appeared not to conform to the legal standard AS 1210.

d) The Regulator who had been CE with AU Welding Research Association was impressed with 5 features:    

i) the unique circumferential weld (welded from the reverse side to normal);  

ii) the shell was made with 3 pieces (5 normally) requiring only 3 welds;

iii) the virtual integral spear (eductor) which would rarely be extracted with a special tool;

iv) improved shape (cylindrical), reduced weight and hence better stacking and handling; and

v) although thinner than AS 1210 code thickness, might be safe or safer and also help improve Standards and reduce beer cost - (a conflict of interest for the Regulator, but would benefit millions)

e) the Regulator advised that:

i) it was probably safe, while not conforming to AU Standards,

ii) it might be acceptable in law if suitable details and proving tests were supplied, and it showed equivalent or adequate safety.

iii) in AU there had been 2 recent BB cases - an explosion and a spear ejection resulting respectively in a serious permanent injury and a death.

f) The CE and the Regulator agreed that safety tests would be carried out by a top PV engineer in an excellent AU University, at brewery expense.( Dr Hugh Stark, UNSW).

g) A series of special tests developed for this case was carried out ie pressure burst, penetration -burst, denting and drop tests. Assessments and experience indicated fatigue and fire tests were not needed.

.3 Human and business factors  These started to become far more dominant than technological factors for the Regulator with:

a) Someone leaked that tests were being done (security had not been discussed) and started resistance to such change).

b) Three PV manufacturers pressurized the Regulator to reject the case (in the national interest and jobs –yes but also?)

c) A Minister from another State objected.

d) One barrel manufacturer met with the Minister for Industry (Pat Hills who was fantastic in handling the director) and the Regulator to reject these barrels. The request was rejected.

e) With some mutual swearing the brewery union blasted the Regulator for giving approval (even though all tests had not been done and no approval given). 10 union members were invited to discuss and see what had been and was being done, but the offer was never accepted.

f) A cleaner at the Regulator’s office noticed barrel parts on the floor, and said he had been at a beer party a month earlier and a drunken mate did not fix the “spear” properly. The spear ejected, flew over the cleaners shoulder and when through 3 walls of the building. A real near-miss, and understandably not reported.

.4 Immediate Outcomes   The barrels passed the final tests and the design was accepted as conforming to AS 1210 - varied to allow thinner shells and on condition of a pressure relief device would prevent overpressure on filling and dispensing of beer. See Story on Empathy for the regulator’s authority to do this.

  The barrels were imported and used successfully.

 .5 Subsequent Events        Almost all of these were unplanned and unexpected and had some luck:

a) There were no fees payable or paid to the Regulatory Authority or others, except a small standard fee for design verification; but a "slab" of beer was donated for a Christmas party by government and industry inspectors.

b) An in-service near-deadly burst of another type of barrel had earlier indicated the new design would not be protected against overpressure when connected to high pressure CO2 cylinders. Beer barrels are not fitted with a pressure relief device. CO2 charging usually had relied on only pressure regulators, so a simple form of rupture disc was developed to avoid bursting in the event of regulator failing in the open position.

c) Then industry queried what happens if the rupture disc fails. It was learnt that about 2 or 3 people died of CO2 asphyxiation each year in hotel cellars across AU; and so requirements were introduced for venting and gas detectors (or having both barrels and CO2 above ground). 20 years later this practice was improved and codified in a new Australian Standard AS 5???

d) It influenced a later dispute between makers re introduction of SS LPG auto fuel tanks with big advantages of no PWHT or painting and reduced weight, but new issues of design against impact and highly localized corrosion cracking of sensitized workhardened SS from triple heat inputs during welding of tee joints to be radiographed.

 .6 National Outcomes   As a result of this innovation which was started by a GM of a big business, national gains (to 2017) are:

a) Barrel explosions and ejection of spears have stopped - saving about 1life per year.

b) Gas asphyxiation is not a problem – saving at least 20 lives in10 years.

c) Backache problems at a brewery where this was huge, are almost nil – saving $millions.

d) It influenced acceptance of PV designs using thinner shells than then allowed by Code, and an innovative design using shock absorbent non-metallic material. It improved LPG car fuel vessels.

e) AU breweries and PV manufacturers gradually adopted a similar type barrel. Fig 2 shows one of these made more conventionally with 4 pieces and 3 welds.

f) The Regulator and all others directly involved did not predict b) to e).

g) After a year everything settled down and many people were much happier.

 . 7 Technology Improvement   The research and overall case added strength to earlier work on cold stretched stainless steel cryogenic vessels - static and transportable.  

a) It confirmed PV design using design strength = 1.3 to 1.6 Rp (Rp = annealed proof stress) and use of work-hardened SS (done in plate production) or with higher N, prestressing before use or at hydrotest. Weld transverse joint strength = about 98% of weld or plate strength due to high hydrotest pressure. Then sometimes, design needs to be determined by limit on diameter increase or drop in Charpy values due to martensite formation in cold work. A rough rule is 15% ferrite or 5% cold work from annealed condition. This practice utilises the continuously rising stress-strain curve of SS - differs from normal carbon steel with a significant yield plateau.

b) Recently a cold spun dished end using 1/4 hard dished end cracked unexpectedly in a transport accident due to ductility and Charpy reduction. Shown by strong magnetism. These are strongly magnetic.

 .8 BB Case Critique.   Decision-making by the PE Regulator was not ideal:

a) It had many omissions – it didn’t consider all physical and human threats and hazards, and didn’t look more than a couple of stages ahead; or really consider the national benefit or cost.

b) It used gut feeling or intuition in believing that barrels were safe and that approval was morally and physically ok.  

c) His engineering background biased a decision for gains from technology, R&D, and innovation,

d) He only partially considered the impact on manufacturing, jobs, free trade,  trade balance. He knew no government policy on these issues as duty was focussed on national safety and health. CO2 fugitive emissions was not dreamed of for climate change.  These omissions were thought to be the functions of other departments who were not contacted – ‘silo thinking”.

e) Now how should the balance be reached between penalizing AU PV manufacturers and helping a big brewery, importers and rewarding excellence and enterprise? Should the Standard have been changed before approval in order to give equal opportunity?

f) Was he influenced by the natural instinct, WWII experience and current trend for maximum freedom and flexibility consistent or in balance with community and national needs?

All of these issues were very briefly, consciously or subconsciously, considered.- trying to “do the right thing “. Life is uncertain. You can only do your best.

 4 CASE 2     CRACKED STEAM MAIN

 .1 Coverage    This case deals with a serious failure and great uncertainties, misinformation, different interests of different parties or businesses, and the uses of scientific method and nature to resolve big risk successfully.

.2 Initial Stage    A State Chief Inspector of Boilers (CIB ie Regulator) had a visit from a senior executive and CE of a large facility. They explained that their main superheated steam pipe had a serious crack, and that it was now operating after the annual 2 day Christmas maintenance shutdown, even though it it had been detected 6 days earlier. They asked what should be done urgently to be safe and comply with the law. The facility employed 500 people in 3 shifts and a shutdown would be expensive.

 (Note: Latest AU planned shutdown maximum cost for a facility is $15 million /day)

.3 Crack details The crack had been detected by UT, extended 1/3 circumferentially around the bore of the pipe, with maximum height = 1/3 pipe thickness and not near any welds, bends or within 500mm of a branch. It was similar to a crack the previous year in another place which was still being investigated by a metallurgist then on holidays.  

See Fig 3.

 

.4 Investigation      

a) Approval was given to continue operation for a maximum of 3 weeks to give time to get full details and any other information including previous failure data from the metallurgist. Access to the nearby area was restricted as far as practicable. This was based a rough quick calculation of the low stress, good toughness at high temperature and its unusual direction, location and size which probably had not occurred suddenly. He was also probably influenced on the 2nd January when he was still in holiday mood and didn’t want to put 500 people out of work. Also he recalled that in 1980 in Düsseldorf at a IIW Creep Working Party meeting of 15, a Professor had remarked that nearly always "creep cracking occurred at an external surface". With his WW II experience he thought the risk acceptable for a short time for the investigation.

b) Then came the bad news. The UT technician reported that the UT attenuation was worse than that on the earlier failure. The CE had contacted a leading AU-UK piping designer-fabricator who advised by telegram a remaining life assessment showed that the current piping operating hours were twice the predicted failure life, and the piping should be shut down. Something else seemed wrong.

c) The Regulator had given much thought to explaining the location, position, direction and extent of the crack. No significant corrosion or material flaw was reported on any bore. If there were excessive bending stress the crack would be on the outside surface. Cracking was not caused by overpressure as the crack was not axial. It could only be creep or fatigue cracking, but both would be axial and/or on the outside surface. There was very little service pressure or temperature fluctuation which would be required for fatigue. A few days later he recalled condensed water droplets running down the inside of windows in winter or saw it on a shower screen. This solved the cause and most of the problem and explained the location, pipe side and direction of the crack. It was considered it to be thermal fatigue cracking caused by periodic collection and flow of condensed cooler water. The stress range was calculated from an estimated temperature change of 50deg. due to water hitting the hotter area of pipe, and its frequency estimated at 1/minute. This gave a point on the AS 1210 figure on an estimated mean failure stress -cycles line within a box of +/- 10% of stress and cycles. This showed at first try that fatigue was a reasonable bet and gave courage to avoid shutdown.

d) The piping people were very competent and their assessment would not be very wrong but must probably based on insufficient or misleading data. A simple fracture mechanics estimate with max. pressure and external loading indicated the crack current size was not near critical. Hence immediate shut down was not requested and could wait for the metallurgist. This stressed the Regulator (and his wife) for about 7 days until he was visited by the metallurgist on return from holidays..

e) Samples from the earlier failures pipe and micro-examination showed internal micro-cracking or extension of micro-inclusions in the steel. These were axial, typical of earlier seamless steel pipe and explained the increased UT attenuation. But their shape and direction would have virtually no effect on the cracking.

f) An urgent visit was then made to the boiler facility, and a bend specimen was cut from the previous failure sample, notched with a standard fine hacksaw and impact bent by hammer. The material was excellent and tough. The material micro-cracking was in a planes parallel to the pipe surfaces and perpendicular to the notch in the specimen and the pipe crack.

g) 20 years of the boiler logs were requested, objected to because a truck was needed, but demanded by the GM . Fortunately the daily log sheets were the same and within 15 minutes the critical data was obtained. Temperatures had on a few occasions for a short time during commissioning and exceeded design temperatures by 50C. These had negligible effect on creep life or other modes of failure but were quoted to the piping people. This explained incorrect remaining life estimate.

.. 5 Final outcome.    

a) 6 months continued operation with a few precautions was allowed for replacement of the piping.

b) This saved offloading people, a few $million and made all happy.

c) In hindsight and now without the unknowns and pressure at the time, only one length of piping needed replacing.

.6 Observation   This case shows the value of the scientific method, attention to detail, identification of failure mode, getting correct data, and making sure all facts agree with the failure model, and most importantly, people cooperation and common objective.

 

.1 Coverage    This case occurred in the early 1950s with a young mechanical engineer given the task of designing a special road tanker (10 off)  for supply of heavy furnace oil to an new oil-fired  power station.

.2 Tanker details  Fig 4 shows the type of tanker .It was designed for the absolute maximum permitted gross weight and for maximum payload. This needed minimum vehicle weight and was a stressed-skin type constructed in carbon steel 3mm thick with internal partial baffles - influenced by aircraft design.

 Design against fatigue was based on a draft USA bridge design standard.

 .3 Failure   After about 3 years the designer was working as a construction engineer at a big oil installation where tankers were filled. He incognito asked a driver what he thought of them. The result was surprising and enlightening.

They were terrific. Easier braking and less surge, visibility on both sides and cornering stability were excellent - not due to the designer because a smaller tank diameter suited the high specific gravity of the oil. When asked of any difficulties, the driver firstly said No, and then reported an incident.

On discharge while standing on the tank top there was a very load explosion, the tank shuddered and he heard hissing at the dip opening. He had knocked the cover over the opening, a vacuum was forming, and with difficulty he managed to lift the cover. Inspection of the tanker showed the only damage was the rear end buckled inward.

.4 Final outcome   On next refilling the tank repaired itself by snapping back to its original shape. Close examination showed a very fine crack in the enamel paint. Tankers performed excellently until the power station closed because of increased oil cost.

.5 Observation  

a) The designer was lucky. He had not thought that the second set of safety VRVs would get blocked by caked oil. Also in the design, baffles also acted as stiffeners to stop buckling at mid-length of the tank; and so the unstiffened slightly dished rear end became the weakest spot.

b) This case first demonstrated that design should if practical consider both the type of failure and post-failure. It went further than leak before burst design and like self-sealing tanks was self-healing for long service life.

c) This inadvertent feedback, sought in this case, was valuable for the designer to learn of the strengths and shortcomings of his design.

 5 SOME PRINCIPLES

At the 8th ICPVT, the author stated that almost all failures are due to human inadequacy, and suggested biggest improvements all round would be gained by better human behaviour - especially in all high hazard situations including those with PV.

Also as demonstrated above, “The price of progress (or change) is problems.

Thus some guiding principles for reducing failures and other problems and make progress are given for technologists, businesses, governments and others to consider. These arebased on the Cases above and wide experience by many and are:

a) Firstly, “principles” are difficult to express briefly and clearly in words and to cover all contexts or situations, and can be gradually improved; and many very hard to apply always.

b) Prove new technology details before application - as far as needed and practicable. “Look before leap”. Prediction is difficult or impossible to cover all factors especially for 100 years. This is seen in Fig 1 in the first years of PV and road vehicle technology, and in the three cases above.

Other notable examples are the inadequate fatigue design causing pressured Comet aircraft crashes, and quick-actuated door release on pressurised aircraft pressure cabin- the worst single plane disaster with over 500 killed near Paris. Recently there have been leaks from low cycle atmospheric LNG vaporizers at power stations; these are similar to 1950 -60s spate of fire tube boiler failures due to thermal fatigue not previously considered in use.

 c) The higher the hazard or consequence of failure, the more checks, controls or proof are needed eg nuclear PV v a Coke can. Doing this responds effectively to society’s natural resistance to change and some mistrust of new technology. This is required in the latest conformity assessment laws and Standards like EU PED and AS 3920 & 4343 which uses equivalent energy as an approximate measure of hazard level or consequence of failure.

d) Think holistically and globally. This was not done in the above and most other cases. In many cases not doing this has been disastrous.

e) Use science-based thinking and principles as far as practicable ie STEM (science, technology, engineering & maths) and the equivalent in business and with human factors. Best advance in technology is probably by “informed science-based democracy” and humanity.

f) Learn from Nature.  All our knowledge comes from here either direct or by ideas, extrapolation and quantification for explanation  eg the key in Case 2. AU aboriginals have a fantastic love of nature and great skill in handling it in AU which is extremely hot, dry, tough but beautiful land.

g) Listen to All available.  – this includes the public and media and not one nation, race, religion, gender , age,, discipline or type of business or technology. Final painters have materially contributed to sinking a submarine and dropping a major bridge, and saving major HEX failure in a major AU refinery. 

However, remember the biggest problem is PEOPLE- many sometimes they lie, omit essential data or provide misinformation.

h) Learn from Failures  Because of our inability to be absolutely sure we have covered everything in initial planning and design, occasional failures will occur. Hence if practicable plan to fail small Fig 4, act quickly if fail, treat failures as expensive experiments to refine design etc, learn quickly what to do to prevent similar failures with similar or future PE or plant , and provide feedback for as many as appropriate. In solving causes and modes of failure ensure all their features and circumstances are reasonably explainable.

i) High Integrity, cooperation, multidisciplinary input and good communication and timing are essential for high risk PV, plant, business, industry and government. etc

j) Recognise that difficulties are likely to increase at changes and interfaces.

k) Ensure adequate documentation. It can save accidents, failures and $s. It needs to be sufficient and minimum, and will vary for big and small business. Case 2 above is an example.

l) Keep in mind the ultimate objective is to help the PV user achieve the required safety and performance (output, quality, on time, economic, and socially and environmentally friendly)

  m) Importance of human needs and qualities was forgotten sometimes. See separate Note on “Empathy in Engineering”. This also showed the wisdom of two top government Ministers and advice from a Deputy Secretary, without whose help the progress would have been greatly delayed.

Challenges to us all will continue to arise and face PV technologists and mankind.

Current ones which are still being resolved include the extension from Automation with Robotics, Artificial Intelligence.

The biggest challenges will involve some technology; but how we and all businesses handle the advantages and disadvantages of technology will be the biggest challenge.eg with COVID etc, wars, climate change, health and the poor.

The use and continual improvement of principles for change can greatly help guide humans.

 7   ACKNOWLEDGEMENT

The great ideas and help in many ways from many persons is gratefully acknowledged.

______________________////////. . SAA. 4/12/2022

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