MIL-DTL-18001L Cathodic Zinc Anode Type ZEP Style A

Lead-freeMIL-DTL-18001L 6" Square and 12" x 12" Sizes Broad Current Distribution Low-Profile Plate Form MIL-DTL-18001L Certified

MIL-DTL-18001L Type ZEP Style A zinc anodes, 6" square and 12" x 12" x 1" thick configurations. Used for cathodic protection of steel hull plates and underwater tanks.

Solidus

787°F (419°C)

Liquidus

787°F (419°C)

Density

0.258 lbs/in³ (7.13 g/cm³)

Primary Elements

Nominal Composition

Bal, 99.55% Zn

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Product Overview

MIL-DTL-18001L Type ZEP Style A Zinc Anodes are flat plate-form sacrificial zinc anodes manufactured by Belmont Metals for cathodic protection of steel ship hulls and underwater steel tanks. The ZEP (Zinc Electrode Plate) designation covers plate-style anodes that are welded or bolted flat against hull plating or tank walls providing a low-profile anode that minimizes protrusion into the water flow while delivering broad current distribution across large flat steel surfaces. Style A square and rectangular configurations are available as 6″ square plates and 12″ x 12″ x 1″ thick with a 1/2″ IPS (iron pipe size) insert for bolt-on applications. The flat plate geometry provides excellent area coverage for protecting large hull plate sections and tank interiors where even current distribution across a broad surface is required. Zinc alloy conforms to MIL-DTL-18001L composition. Available with 1.5″ IPS insert configurations for secure installation.

Available Forms

12" x 12" x 1" Thick w/ 1/2" IPS Insert, 6" Squares

Product Code

8001A

Technical Info

Thermal Properties

Melting Point (Solidus)787

Melting Point (Liquidus)787

Physical Properties

Density (imperial)0.258

Density (metric)7.13

Physical Properties

Primary ElementsZn

SpecificationMIL-DTL-18001L

Lead FreeYes

Performance tags

6" Square and 12" x 12" SizesBroad Current DistributionLow-Profile Plate FormMIL-DTL-18001L Certified

Nominal Composition

99.55% Zn
Bal

Frequently Asked Questions

Common technical inquiries regarding MIL-DTL-18001L Cathodic Zinc Anode Type ZEP Style A

ZEP plate anodes are used inside ballast tanks, void spaces, cargo tanks, and other interior steel compartments that are periodically flooded with seawater or ballast water. The flat low-profile plate can be welded flush to the tank interior plating minimizing interference with tank cleaning operations and structural access. ZEP plates are also used on the flat exterior hull bottom of large vessels where the minimal protrusion of a flat plate reduces bottom drag compared to slab or oval anodes. The bolt-on IPS insert versions are used in tanks where welding is not permitted due to cargo or fire hazard.

The 12" x 12" plate provides four times the zinc mass of the 6" plate at approximately 1" thickness - roughly 20-22 lbs versus 5-6 lbs. The larger plate protects a proportionally larger tank area at a given service interval reducing the number of anodes required in large tanks. The 6" square is used for smaller void spaces, localized protection of specific fittings, and applications where tank geometry constrains the maximum anode size. Both provide the same zinc alloy composition and protection potential.

The IPS (iron pipe size) threaded insert provides a steel pipe thread in the zinc body that allows the anode to be bolted to a mating fitting or threaded stud welded to the tank interior or hull plating. This bolt-on method is used in compartments where direct welding to the hull is prohibited - petroleum cargo tanks where welding presents fire and explosion risk, compartments adjacent to fuel systems, and tank linings with protective coatings that would be damaged by weld heat. The steel insert also provides a secure metallic electrical connection between the anode and the protected steel structure.