The key defining characteristic of electro-galvanized pipe is its thin zinc coating. Typical coating thickness ranges from 5 to 25 micrometres (µm) per side, which is significantly thinner than the 45 to 200 µm coating typical of hot-dip galvanized (HDG) pipe. In terms of coating weight, electro-galvanized pipe generally has a zinc layer of approximately 20 to 100 g/m² total, compared to 180 to 500 g/m² for HDG. This thinner coating results in lower material cost but provides only moderate corrosion resistance suitable for mild, indoor environments.

The electroplating process offers several advantages. It produces a precise, uniform coating thickness that can be accurately controlled. The surface is bright, smooth, and spangle-free, giving the pipe an attractive appearance. The pure zinc coating is ductile and does not crack during bending or forming. Additionally, the smooth surface provides excellent paint adhesion if further finishing is required.

However, electro-galvanized pipe has important limitations. Because the zinc coating is much thinner than hot-dip galvanizing, it provides sacrificial corrosion protection for a shorter period, typically 2 to 10 years in mild environments, compared to 25 to 75 years for HDG. Electro-galvanized pipe is not suitable for outdoor exposure, buried applications, or persistently wet conditions. It is also not recommended for high-temperature service above approximately 300°C, as the thin zinc layer may degrade.

Standards applicable to electro-galvanized steel pipe include:

● ASTM B633: Standard Specification for Electrodeposited Coatings of Zinc on Iron and Steel, covering four standard thickness classes and supplementary finishes.

● ISO 2081: Metallic coatings — Electroplated coatings of zinc on iron or steel.

● ASTM A153: Standard Specification for Zinc Coating (Hot-Dip) on Iron and Steel Hardware, also referenced for certain electro-galvanized applications.

● For electrical conduit applications, EN 61386-1 covers rigid electro-galvanised steel pipes for mechanical protection of cables.

The base steel grades used for electro-galvanized pipe typically include low-carbon steels such as Q195, Q235, ASTM A53 Grade A/B, St37, S235JR, and SS400. Common dimensions include outer diameters from 10 mm to 609.6 mm (1/2 inch to 24 inches NPS), wall thicknesses from 0.5 mm to 12 mm (or SCH 10, SCH 40, SCH 80), and standard lengths of 6 metres or 12 metres, with custom lengths available.

Typical applications of electro-galvanized steel pipe include:

● Electrical conduits for mechanical protection of cables in indoor installations.

● Indoor plumbing and water supply lines in dry environments.

● Lightweight structural frameworks, shelving, and metal furniture.

● Automotive components and small hardware.

● HVAC ductwork and ventilation systems.

● Fencing, handrails, and guardrails for interior use.

● Fire protection pipe networks (ASTM A795 standard) in certain applications.

Electro-galvanized pipe is not recommended for outdoor structural use, coastal or marine environments, buried pipelines, or any application requiring long-term corrosion resistance in wet or humid conditions. For such demanding environments, hot-dip galvanized pipe is the appropriate choice.