TESTMARK Laboratories
Testmark and AEL Continue to Grow
OVER THE PAST YEAR, ALL FOUR OF OUR ONTARIO LABS HAVE CONTINUED TO GROW THEIR TESTING CAPABILITIES.
Our business model has always been to invest locally - to put real infrastructure and real jobs in the communities in which we work. The importance of a sound relationship between industry and their local lab cannot be overstated. The past year has seen over 30 new accredited methods implemented across our locations.
- All sites now offer microbiological testing, nutrient analysis programs and a robust suite of inorganic chemistries.
- Capabilities in metals, organics and toxicology continue to expand at our Garson and Mississauga locations.
- Our cyanide program has been enhanced at our Timmins and Kirkland Lake sites, along with the implementation of mercury by cold vapour.
Our plans for 2016 will see the trend to invest in localized testing continue and the development of more testing capabilities in response to client demand.
Corrosion Testing
Corrosion testing is an important consideration in most engineering projects. Whether the intent is to analyze the corrosive potential of water in water treatment, water transport or water holding applications, or understand the corrosive potential of soil when building new structures, determining how corrosion may impact infrastructure should be part of the overall design strategy.
SOIL CORROSIVITY FACTORS:
Soil that is highly corrosive is a large risk factor for in-situ concrete, pipe and metal structures. The nature of the soil in the contact zone immediately surrounding the structure should be analyzed to assess its corrosive potential. Unfortunately, there is no one definitive test for corrosivity; it is a collection of tests, the results of which paint the overall picture of the risk.
The main tests to consider are:
- Resistivity – resistivity of soil is a measure of how resistive soil is to ionic current flow. High ionic current low creates an environment that facilitates soil corrosion reactions, so soils with high resistivity (i.e. low ionic current flow) tend to slow down corrosion reactions.
- Conductivity – is the reciprocal of resistivity. A highly resistive soil is therefore expected to exhibit low conductivity and be less corrosive.
- Moisture – the water content of the soil is a good indicator of the corrosive potential of the soil, and some suggest it is the best predictor of corrosivity. In general, soil with high moisture content tends to decrease the resistive nature of the soil, can carry more destructive reactive salts and ions and fosters greater corrosive reactions.
- Particle Size Analysis – PSA analysis allows one to characterize the particulate nature of the soil. With size classifications ranging from coarse rock through to clay, it provides a profile of the granularity of the soil. Coarse soils tend to hold little water and are high up on the resistivity scale, while clay soils tend to hold a lot of water and are less resistive and more corrosive. This is particularly true when the water is saline.
- Reactive Cations and Anions – Sodium, chloride and sulphate tend to be highly reactive parameters and the greater their concentration in the soil, the more corrosive the soil.
WATER CORROSIVITY FACTORS:
Corrosive water can lead to pitted and abraded pipes, rusting tanks and can pose a challenge for optimizing chemical water treatment processes. Similar to soil corrosivity, determining the corrosive nature of water means considering a number of tests.
Water studies for corrosion should focus on:
- pH – low pH tends to favour corrosive reactions. High pH may create chemical scaling that can help protect against corrosion but it may also foster bacteria such as sulfur-reducing bacteria that can promote microbiologicallyinduced corrosion.
- Field Observations – field observations with respect to temperature and flow rate are important to assess. Microbiological activity generally increases with increased temperature and so does the rate of some chemical reactions in general. High flow rate has the potential to physically wear at structures over time, and increase the potential for contact with corrosive salts.
- TDS and TSS – water high in suspended solids causes physical abrasion on surfaces and coatings; high dissolved solids may pose a risk if they are salts or sulphates.
- Dissolved Gases – the presence of significant amounts of dissolved gases (particularly oxygen and carbon dioxide) can induce corrosion.
- Reactive Cations and Anions – similar to soil, reactive parameters such as sodium, chloride and sulphate can signal a corrosive environment.
The following provides a general rule-ofthumb when assessing the main criteria in soil corrosion studies:
While the above provides a general benchmark, care must always be taken to consider all variables in your project, not the least of which is the actual application and material you are working with (concrete, steel, polymer-coated metal etc.). Testmark can assist in providing testing specific to your requirements.
Source: https://testmark.ca/wp-content/uploads/2019/10/Testmark-and-AEL-Continue-to-Grow.pdf
