A round robin evaluation of the corrosiveness of wet residential insulation by electrochemical measurements

Technical Report · Tue Oct 01 00:00:00 EDT 1991

DOI:https://doi.org/10.2172/6232230· OSTI ID:6232230

Stansbury, E E ^[1]

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1. Stansbury (E.E.), Knoxville, TN (United States)

The results of a round cabin evaluation of the use of an electrochemical method of calculating the corrosion rate of low carbon steel in environments related to cellulosic building insulations are reported. Environments included the leachate from a wet cellulosic insulation and solutions based on pure and commercial grades of borax, ammonium sulfate and aluminum sulfate. The pH values of these environments were in the range of 2.5 to 9.5. Electrochemical measurements were made using a direct reading corrosion rate instrument. The calculated corrosion rates were compared with those determined directly by weight loss measurements. Electrochemical measurements were made over a period of 48 hours and weight loss exposures were for two weeks. Poor agreement was observed for the corrosion rates determined electrochemically and the values were consistently larger than those based on weight loss. Reasons proposed for these results included the complex nature of the corrosion product deposits and the control these deposits have on oxygen diffusion to the metal interface. Both factors influence the validity of the calculation of the corrosion rate by the direct reading instrument. It was concluded that development of a viable electrochemical method of general applicability to the evaluation of the corrosiveness of wet residential building thermal insulations were doubtful. Because of the controlling influence of dissolved oxygen on the corrosion rate in the insulation leachate, an alternate evaluation method is proposed in which a thin steel specimen is partially immersed in wet insulation for three weeks. The corrosiveness of the wet insulation is evaluated in terms of the severity of attack near the metal-air-wet insulation interface. With thin metal specimens, complete penetration along the interface is proposed as a pass/fail criterion. An environment of sterile cotton wet with distilled water is proposed as a comparative standard. 9 refs., 2 figs., 3 tabs.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Stansbury (E.E.), Knoxville, TN (United States)
• Sponsoring Organization: USDOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 6232230
• Report Number(s): ORNL/Sub-90-SF204/2; ON: DE92003220
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
42 ENGINEERING
36 MATERIALS SCIENCE
THERMAL INSULATION
ELECTROCHEMICAL CORROSION
MATERIALS TESTING
ALUMINIUM SULFATES
AMMONIUM SULFATES
BORAX
CARBON STEELS
CELLULOSE
COTTON
LEACHATES
PH VALUE
RESIDENTIAL BUILDINGS
ALKALI METAL COMPOUNDS
ALLOYS
ALUMINIUM COMPOUNDS
AMMONIUM COMPOUNDS
BORATES
BORON COMPOUNDS
BUILDINGS
CARBOHYDRATES
CHEMICAL REACTIONS
CORROSION
DISPERSIONS
IRON ALLOYS
IRON BASE ALLOYS
MIXTURES
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
POLYSACCHARIDES
SACCHARIDES
SODIUM COMPOUNDS
SOLUTIONS
STEELS
SULFATES
SULFUR COMPOUNDS
TESTING
320107* - Energy Conservation
Consumption
& Utilization- Building Systems- (1987-)
420500 - Engineering- Materials Testing
360105 - Metals & Alloys- Corrosion & Erosion