Corrosion in Dairy Barns
Without protection, steel is prone to rust. Cattle equipment, in particular, faces significant rust risks due to exposure to the elements year-round and the corrosive effects of cattle manure, liquid fertilizers and milk. While paint has traditionally shielded steel from environmental damage, its protective abilities diminish over time. Chips and defects in the coating will allow moisture to seep underneath, leading to rust beneath the paint layer. Moreover, painting only safeguards the external surfaces, leaving steel tubing vulnerable to moisture internally.
While replacing and repairing corroded barn equipment is expensive, there is a bigger issue caused by corrosion that is considered one of the most serious problems not only dairy, but many other types of livestock farms face.
From producer.com this article on how corroded wiring can be deadly:
“We feel approximately 60 to 70 percent of all barn fires are caused by deteriorated electrical/mechanical equipment and faulty/improper heating devices, which are open ignition sources,” said Jim Zyta, vice-president of loss prevention with Heartland Farm Mutual, a firm in Waterloo, Ont., that specializes in agricultural and rural insurance.
“The wiring and electrical systems in hog, poultry, and dairy barns often cause fires because they are humid and have elevated levels of corrosive gases such as hydrogen sulfide and ammonia.
The harsh atmosphere corrodes wiring and electrical connections, creating the ideal conditions for arcing or overheating of wiring.”
This fact sheet produced by the Ontario Ministry of Agriculture, Food and Agribusiness and Minister of Rural Affairs states “The electrical system components used in the barn must be specifically designed to withstand the barn’s corrosive and wet environment,”
“….the importance of a properly ventilated barn “ventilate livestock buildings at all times, including when no livestock are present, to avoid humid, corrosive or explosive environments”
They outline several ways to combat this issue on your farm, starting with good ventilation & housekeeping. They also mention using the correct NEMA rating: “The National Electric Manufacturers Association (NEMA) rates electrical components from Type 1 to Type 13, with higher ratings indicating a greater ability to withstand wet, dusty, and corrosive environments. For barns, the minimum rating is NEMA 3, and NEMA 4X is recommended for livestock housing areas.”
What are the most problematic substances corroding the steel in your barn?
If you are within 8km to the coast, you are already fighting more corrosion than your inland peers.
However, there are three main culprits common to all Dairy Farms:
Commercial liquid fertilizers
According to National Physical Library “frequently damaging to farming structures and machinery, as revealed in the recent study, include acid preservatives and additives, certain fertilizers and manures or slurries”
“….aggressive substances such as ammonia or hydrogen sulphide, if chloride ions are present (including potassium or ammonium chloride), or if acidic conditions prevail. For example, dihydrogen ammonium phosphate or ammonium nitrate can lead to increased corrosion via hydrolysis to acids (i.e. a fall in pH).”
Important to note: If fertilizers are kept dry, then no corrosion occurs. Store fertilizers in a cool dry location where they will not encounter any moisture in the air or on the ground.
Farm waste and slurries
“farmyard manure (FYM) is slurry composted with litter, i.e. straw or wood shavings, etc. Both ferment to release moisture, ammonia and carbon dioxide. The corrosive constituents in slurry and FYM are urea, uric acid, ammonia and ammonium salts, and naturally excreted chloride (common salt), and the mixture is corrosive towards steel structures and machinery that are poorly protected and maintained.”
Milk Waste
This is not a new problem. We found a study called “The Corrosion of Metals by Milk” from 1932 on sciencedirect.com that stated:
“…the corrosion of metals by milk is one of the most serious corrosion problems facing modern civilization and industry.” From The National Physical Library paper entitled “Corrosion Control of Agricultural Equipment & Buildings” “…there being a particular need to protect mild steel supporting structures from milk wastes; lactic acid, for example, can remove 1.25 mm of steel in one year.”
So what corrosion protection is available to dairy farmers?
The biggest protection you have from dairy related corrosion will be by designing your barn and systems in a way that eliminates as many corrosion creating elements as possible. If you are long into an older operation, a preventative maintenance protocol that includes the regular cleaning of areas & equipment that are in direct contact with milk, slurry or corrosive chemicals like fertilizers. Work with a Ventilation Specialist to assess your system & make adjustments that help slow the effects of corrosion. Ensure when purchasing any new barn equipment that everything has been designed to help fight dairy corrosion.
Lets take a quick look at the corrosion protection coatings typical in the dairy industry and which is best for what:
Pre-Galvanized Steel
When steel components are being manufactured into a more complex finished product, they undergo pre-galvanization before final assembly. Also known as ‘pre-gal,’ this process may be referred to as ‘in-line,’ ‘continuous,’ or ‘mill’ galvanizing. Essentially, steel components—such as tubes—are galvanized using an automated method prior to being cut to size.
The specific process varies based on the type of component being galvanized. Generally, components are immersed in a ‘galvanizing bath’ of molten zinc for a brief period as part of the manufacturing “line”. After removal from the bath, excess zinc is eliminated using a mechanical wiper, air knife, or steam, resulting in a relatively thin galvanized zinc coating.
Hot Dipped Galvanized Steel
Hot-dipped galvanizing employs zinc to shield against corrosion, creating a stronger bond than paint. This process dips an entire component after final assembly. When that component is exposed to the elements, the surrounding zinc acts sacrificially, preserving the underlying steel. The dipping process ensures a uniform coating that penetrates pipes and other components, safeguarding equipment from the inside out. Hot dipped components generally have better coating continuity. Hot-dipped galvanization provides a permanently bonded thicker layer of zinc, significantly enhancing corrosion resistance. This ensures long-term durability and minimal maintenance. Both zinc and steel are natural, abundant, and 100% recyclable. Hot-dip galvanized steel is an infinitely renewable building material. Complex fabrications are entirely coated for corrosion protection due to the total immersion process. While Galvanized Steel is weaker than stainless steel, it is still a much more cost-effective coating for outdoor applications. The cost of Galvanized Steel is comparable to untreated structural steel. Another good benefit is most welders can work with Hot Dipped Galvanized equipment, though protection against fumes is necessary. Avoid exposure to chlorinated water and damaging coating with machinery, as any chips in coasting leaves the steel underneath vulnerable.
Stainless Steel:
Made by adding chromium to molten steel, stainless steel is strong and highly resistant to rust—even when exposed to saltwater.
Stainless steel is generally non-corrosive, ensuring durability and a long-lasting solution. “Type 304 stainless steel has shown overall benefit for liquid fertilizer service over three-year service tests.” Since stainless steel is non-degradable, it is 100% recyclable and cannot be damaged during the recycling process. Stainless is always stronger than galvanized steel, especially when comparing similar thicknesses and shapes. Stainless is significantly more expensive (four to five times) than galvanized steel or untreated structural steel. In application, Stainless Steel requires specialized welding skills & equipment. You should avoid any design in which two stainless steel components generate friction against each other as they can weld themselves together.
Big Ideas happening in Corrosion:
This idea came from the Canada Wide Science Fair hosted by the University of New Brunswick where 16 year old Mark Norregaard set out to identify a 100% plant based organic corrosion inhibitor that can be grown in Canada.
“My study was a focus to find more organic corrosion inhibitors and specifically ones that can be grown in Canada,” said Norregaard. “So, I found three different ones, dandelion, ginger and sweet potato.”
“The idea for his corrosion inhibitors came because “corrosion is a common occurrence in many different industries. Some of those industries use corrosion inhibitors and most of the corrosion inhibitors are toxic or detrimental to the environment.”
So far, these substances are not being tested commercially, but initial tests are showing potential for them to be a more sustainable and environmental/animal/person safe solution.
What are we doing to help you fight corrosion:
All of our products that will get more exposure to corrosive environments like water troughs, robot gating, anything touching manure, or anything that will be covered in bedding material receives corrosion protection.
We have created stainless steel product lines for the best corrosion resistance where its needed the most, like with our troughs.
Around tubes and posts that contact the ground in high corrosive areas (i.e. touching manure) we have added optional heat shrink post sleeves that go around the post so there is little to no gap for the manure to touch the steel of the post. The wrap is made from plastic, and therefore provides much greater corrosion resistance than steel.
Smaller components like the threads on bolts/U-bolts tend to lose their protective coating as they are used in application. We have introduced Dacromet coating on these smaller items to provide a significant upgrade in corrosion resistance.
Finally, we design our products so they don’t have pockets, sharp corners or dead ends to ensure the HDG process is as effective as possible without leaving heavy galv. slag on the final product.
We hope this was helpful to you in learning more about fighting corrosion, and we are wishing you a rust free future!
