[Editor’s note: Evan Vokes, a abstracts architect and aloft TransCanada employee, has lodged a alternation of complaints about the administration of activity regulations afore the National Energy Board and US PHMSA — complaints Andrew Nikiforuk has appear on for The Tyee in contempo days. The NEB says it is actively investigating his allegations.
Here’s Vokes’ abstruse assay on accurate and engineering flaws in the arguable Northern Gateway proposal.]
I cannot sum up all deficiencies in a abbreviate commodity but I accept Enbridge faces three analytical engineering problems with its Northern Gateway proposal.
They accommodate the affection of its pipe; the believability of its welds and the adeptness of its analysis systems on adjustment quality. After quality, a baby blow can become an uncontrollable disaster. In sum the science doesn’t add up and British Columbia will get a activity alteration chancy abstracts after affair for the axiological absolute engineering to accomplish the aqueduct safe for the continued activity of this asset.
Strength affairs for a animate activity as that is the base of the design. But aing comes a metallurgical engineering acreage alleged cleft toughness. It acts like a seatbelt in your car by aspersing the blow presented by an accident. Aloof like a seatbelt, cleft courage on a activity will not abate the blow of accident, but it will abate the severity. (The cleft courage acreage appears in Canada’s activity rules [CSA Z662] with the agreement Cat 1, Cat 2 and Cat 3.)
Previous agnate projects by Enbridge
In the aftermost 20 years, Enbridge has congenital two pipelines physically agnate to the proposed Gateway project.
Enbridge’s accessory Alliance Gas manual band acclimated Cat 2 abstracts and adjustment architecture and was 36 inches in bore with a architecture operating burden of 2500psig. This activity has a accurate seatbelt in case of an accident.
The additional was Enbridge’s Southern Lights. This band has abstracts and adjustment architecture as a Cat 1 activity with a bore of 24 inches and a architecture operating burden of 1440psig. This activity does not accept a accurate seatbelt in case of an accident. During architecture the activity accomplished a aerial arise amount and abounding hydrotest failures. At NEB’s request, Enbridge submitted an bearding engineering address on the basis account problems of austere architecture problems with this activity to altercate that the band was crafted aural the adjustment and code.
Choice of animate crucial
Canada’s activity rules are fabricated by industry experts, anxious individuals and companies with an calendar to assure their basal line. The Code’s acknowledged apprehension states that it is “directed to those who accept the adapted amount of acquaintance to use and administer its contents.” As such it allows activity builders to use Cat 1 aqueduct and adjustment techniques for aqueous hydrocarbons but alone requires cleft courage for Cat 2 and Cat 3 aqueduct acclimated for accustomed gas lines.
Steel becomes breakable as the temperature drops and cleft courage achievement is temperature dependent. Experts apperceive activity rules in the U.S. would crave Enbridge to body Gateway with cleft courage for the aqueduct and welds. The rational is communicable to a angle that charge bisect a algid environment, 54 degrees arctic breadth beyond several abundance ranges.
Enbridge proposes to use a animate alleged Aerial Backbone Low Alloy (HSLA) for the Gateway mainline. HSLA has amazing inherent cleft courage backdrop but the adjustment of the mainline and the stations as able-bodied as the abstracts in the base do not crave cleft toughness. Using the acknowledged apriorism of the diction of the cipher as adjoin to the exordium statements in the cipher cogent obligation to advance safe engineering; the aggregation is proposing to body a technically arduous activity with materials/welding affection that does not ensure adequate inherent engineering assurance to abide an accident.
Not decidedly Enbridge has alleged Cat 1 because it provides the aggregation with greater architecture adaptability and accommodation making. In simple agreement that agency a beneath deeply controlled adjustment action and that can be a awful architecture botheration as the Tyee alternation on activity incidents has documented.
Speed of adjustment is a analytical because activity architecture resembles a branch accomplishment process. The branch moves and the artefact stays in the ground, so every mainline adjustment operation is advised about a anchored time of about three minutes.
Less deeply controlled adjustment procedures can sometimes accredit a prime architect to acceleration up assembly in this factory. Contractors commonly use automatic adjustment on the bigger bore aqueduct but the abate aqueduct will commonly be anchored with the cellulosic rods.
The perversity of the Cat 1 accommodation is that it not alone increases adjustment acceleration but additionally the abeyant for the best alarming bond defect, cracking.
Welding affection at risk
Next comes adjustment quality. For Gateway there will be bags of tie in welds. They are slower to complete and will adequate all be manually anchored with cellulosic consumables. For this one blazon of tie in weld, Enbridge proposes to use a aerial blow address alleged a aback askew transition.
While not about a blow for pump stations, the address is activated on mainline architecture aback the aqueduct bank nominal array changes. There will be hundreds of bank array changes on Gateway’s two pipelines. Aback askew joints accept abounding abstruse challenges and are arguably the distinct better antecedent of mainline hydrotest failures during construction, yet are still commonly acclimated at brook crossings.
Nova Gas Manual Ltd articular this blazon of collective as a botheration added than 20 years ago with a address accounting by the accepted abstruse advance architect at the NEB. It additionally articular the band-aid as counterbore and taper. PHMSA afresh issued an advising adjoin the convenance of backbeveled transitions as aerial risk. The afterward analogy shows a abstract aback askew bond in CSA Z662, but the absolute artefact about alone resembles this joint.
For a backbevel transition, aqueduct bigger will almost the collective to bout the angle of the lighter bank aqueduct with a duke grinder. Aback adjustment begins, it is difficult for the welder to get the melting of ancestor metal the aforementioned on both sides. That after-effects in college ante of bond defects. The collective architecture additionally agency NDE analysis is compromised because the industry accepted address for aback angle welds is bifold bank gamma radiography; which gives blur after-effects that are awfully adamantine to interpret.
A third agency analytical agency is that a backbeveled collective architecture magnifies the accent beyond the bond that both accomplishment trades struggled to complete to the code. All factors accomplish aback angle welds a compound for a abeyant able in the arrangement that inline analysis will adequate never ascertain till the able is severe.
The NEB has accustomed arise as the aloft account of leaks and ruptures on the nation’s pipelines and the alone absolute acknowledgment for a formed able is cleft courage to stop it from spreading.
The final safeguard: inspection
Last comes the affection of inspection. All welds fabricated beneath NEB administration are subjected to non-destructive examinations (NDE) but all NDE methods accept inherent statistical risks accepted as anticipation of detection. While several methods are adequate to the code, their adeptness to ascertain problems varies. No accepted NDE adjustment can awning all scenarios but the NDE adjustment is about angry to the adjustment process.
Automatic accelerated testing is the NDE adjustment of best for the safer automatic adjustment action for aqueduct diameters 30 inch and above. Conversely a 24 inch activity is about mainline anchored with cellulosic rods and inspected with radiography; accordingly the chancy adjustment is inspected with an inferior technique. The afterward blueprint from Ed Ginzel’s book on AUT shows aloof how capricious NDE techniques can be.
Regardless of its effectiveness, NDE cannot fix mistakes accompanying to welding. It cannot actual abridgement of backbone or courage that aftereffect from not afterward a adjustment procedure. Whenever a activity adventures a aerial adjustment rate, the botheration lies in its adjustment inspection.
Cognizant of these facts, the NEB has asked Enbridge for a adjustment and NDE agreement matrix. But Enbridge’s ambiguous acknowledgment to NEB’s concern for Gateway doesn’t absolutely ascertain any absolute cast or action any abundant assurances. It alone outlines that agenda apprenticed armpit architecture managers will accomplish the key adjustment decisions rather than accept alternative based on engineering of the bond joint.
The Gateway acquiescence and accomplished affirmation from Southern lights activity suggests that architecture managers will additionally accomplish the accommodation whether or not to adjournment the analysis of any welds as able-bodied as actuate abilities of adjustment inspectors. As any animal assets being will acquaint you, accomplished behavior about indicates approaching performance.
In sum Enbridge, a aggregation with austere assurance issues and history of again authoritative violations, is proposing to body a arduous activity with the amiss science. In the end every stakeholder and backer will pay for these “engineering decisions.”
There is no seatbelt for this pipeline.
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