Technical Bulletins > E36

11/20/07 - Material Compatibility and Storage of Cryotech E36® Liquid Runway Deicer

Customers frequently ask if materials used in their storage, handling and application equipment are compatible with potassium acetate runway deicers. There are technical differences in the formulation of corrosion inhibitors and pH between potassium acetate deicers from various producers. Therefore, some differences in material compatibility are expected. This bulletin applies to Cryotech E36®, which is 50% potassium acetate by weight.

CORROSION INHIBITORS
E36 contains less than 1% proprietary corrosion inhibitors. These inhibitors create a protective barrier on the surface of various metals. Their performance is tied to fluid pH which for E36 is in the range of 10.5 to 11.5.

Diluted E36 biodegrades naturally when exposed to air. This is an important reason for using the deicer. But by-products of the activity can be unsightly biological growth and superficial staining/corrosion. Therefore, the exterior surfaces of application equipment should be rinsed routinely with warm water after use.

EQUIPMENT CONSIDERATIONS The following guidelines should be considered when selecting equipment to transport, store and apply E36:

• Pumps:Stainless steel positive displacement pumps or properly sized centrifugal pumps with mechanical seals are preferred. Avoid pump bodies made of brass, cast aluminum or cast iron, because some castings are poor quality and may have reduced service life. Avoid large bore, low head (pressure) "trash" pumps. And avoid pumps with brass, zinc or galvanized wetted parts.
• Pipes:Stainless and carbon steel, PVC, polyethylene and rubber are okay. Avoid galvanized metals because potassium acetate will react slowly with zinc giving off hydrogen gas.
• Transfer Hoses:We recommend wire reinforced chemical hoses with cross-linked polyethylene lining and an EPDM rubber cover. They should be rated for the system's pressure and vacuum. Stainless steel cam and groove fittings with locking cam levers and EPDM gaskets are also recommended.
• Tanks:Stainless steel, fiberglass or polyethylene are preferred. Carbon and alloy steel tanks may be used if clean and rust free.
• Gaskets and Seals:Butyl rubber, ethylene propylene rubber (EPM, EPDM), isoprene and natural rubber are preferred. Nitrile (Buna N), hypalon and neoprene rubber are acceptable. Avoid butadiene, fluorocarbon rubber, fluorosilicon, polyacrylate, polyurethane, SBR rubber (Buna S) and silicon rubber.

INSTALLATION CONSIDERATIONS
Obtain professional engineering assistance to ensure proper design and installation of tanks and components. Make certain the system has relief valves and low point drains, and that block valves can be opened without operator risk. Avoid dissimilar metals or provide properly engineered insulators to minimize the effect of galvanic corrosion. Potassium acetate has low viscosity and low surface tension. Therefore, high quality joints are needed for a leak-free system. Welded or flanged pipe joints are recommended. But if threaded fittings are used, a high quality pipe sealant is important.

STORAGE CONSIDERATIONS
If requested, a non-persistent, environmentally friendly blue dye is added to E36 to provide maintenance personnel with a visual indicator both in fluid storage and during application. This dye is specially formulated to dissipate after application and not cause staining of commonly used materials. It is water soluble, washable, and can be quickly removed with a weak bleach solution. Since the blue dye is not UV resistant, it will fade when exposed to sunlight. Therefore, when using a sight glass fluid level indicator, installation with a float or bobber will be helpful as the blue color may fade over time. In un-coated steel tanks, the dye color may gradually fade after one to two years in storage. As the dye fades, a color change to purple or pink may occur. To minimize the potential for the dye fading, totes should be stored indoors; however, if outside storage is necessary, totes should be covered with an opaque tarp. Additional liquid dye concentrate is available for purchase from Cryotech.

AVOID PROBLEMS
Do not use E36 with galvanized (zinc-plated) metals.
Do not use any deicer including E36 on poor quality concrete.
Do not mix E36 with deicers from other manufacturers.