NACE International San Joaquin Section Annual BBQ

NACE San Joaquin Section April Meeting

Girth Weld ILI Tool

Sodium Hypochlorite Storage Tanks

Fiberglass storage tanks containing Sodium Hypochlorite will not have a rupture failure but typically last less than 15 years in service.  Therefore, many operators will store Sodium Hypochlorite in fiberglass tanks.

Poly tanks are more economical than fiberglass storage tanks and may have a service life up to 20 years storing sodium hypochlorite.  However, poly tanks may rupture in service resulting in complete spillage of tank product with expensive environmental clean-up. 

Therefore the risk of poly tank rupture with environmental clean-up needs to be considered when deciding to use fiberglass or poly tanks to store sodium hypochlorite. 

Corrosion Damage to Vessels Have to Be Accurately Measured & Documented

I found myself as corrosion / integrity consultant of a low pressure vessel  built to API 620 standards.  The vessel was in the process of being recoated after ten years of service.  During removal of the coating internal and external corrosion damage was reported to exist on the vessel.   My company was asked to do a integrity accessment and recommend how the corrosion damaged vessel was to be repaired.

The corrosion damage reported on the internal surface didn't appear consistent with internal corrosion damage.  A NACE International Level 2 Coating Inspector with a ultrasonic thickness gauge had done the measurements.  In addition, the corrosion damage was not reported in a format that allowed any calculation of the remaining strength of the vessel wall.

An API inspector and myself entered the vessel to inspect the internal corrosion damage.  We found construction defects which didn't impact the integrity of the vessel being improperly called out as corrosion damage with inaccurate ultrasonic wall thickness measurements.  Basically we found no evidence of any internal corrosion pitting and very minor construction defects which didn't impact the integrity of the vessel wall.

The coating inspector didn't use a pit gauge but put his ultrasonic thickness gauge on rough surface manufacturing defects which caused inaccurate measurement of deep corrosion pitting.  Research on the vessel operating conditions indicated that internal corrosion was highly unlikely as the conditions inside the vessel didn't support corrosion.  Therefore, the fact that the API inspector and myself couldn't find any internal corrosion pitting was to be expected.  This type of vessel in this service has a history of zero internal corrosion issues.

Nine locations of external corrosion pitting caused by coating failure in a Pacific coast atmosphere had resulted in the need to do weld-fill repair which took about a week to complete.  These corrosion pits were small in size yet deep enough to require repair.

It is important that anyone doing ultrasonic wall thickness measurements on a API 620 or similar vessel know ASNT, API, and ASME methods to accurately measure and document corrosion pititng damage.  A coating inspector may be qualified to do coating inspection, but not qualified to document corrosion damage to a vessel. 

ASM – ASCE – NACE TEMECULA COMBO Meeting

ASM – ASCE – NACE TEMECULA COMBO Meeting

April 24, 2014 Thursday DINNER Meeting
"What Really is Involved in Materials Selection"

Speaker: Dr. Robert C. Klug, P.E.

TIME:

6 PM Social Hour & Pizza

7 PM – 8PM Presentation & Questions

Location:

Pat & Oscar’s, 29375 Rancho California Road, Temecula, CA

(951) 695-2422  Cost: $20.00

MENU:

Pizza, Chicken, Salads

PLEASE RSVP by Wednesday, April 23, 2014 but walk-ins are welcome.  Contact Eddie Hernandez to RSVP via email at ehernandez@vglabs.com or (951) 215-6399 

Presentation attendance counts for

(1) Professional development contact hour.

At first blush Materials Selection sounds like a relatively easy process.  However, the number of variables can rapidly multiply and the simple “walk in the woods” can quickly become a struggle to extract yourself from the quicksand.  We will explore what the principle objectives are that you need to consider and how to avoid the quagmire of processing, cost, and design considerations to successfully bring a product to the market, choosing products, and avoid being sued.   

Dr. Klug has worked as a cook, machinist, and welder before earning his doctorate at the Colorado School of Mines Steel Research Center in 1989.  He has worked in a variety of Metallurgical Engineering positions ranging from large Corporations to small independent consulting firms in fields spanning failure analysis, expert litigation support, quality control, education and technical services. Bob and his wife Sharon moved to San Diego in July 2011 where he presently works with the Materials and Processing Department at Solar Turbines Inc.   

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