Hot-dip galvanizing is the core process for corrosion and rust prevention of steel lighting poles. The standard and thickness of the zinc coating directly determine the outdoor service life of the light pole. Many engineering procurement and lighting construction companies are often unclear about national standards, thickness classifications, and scene adaptation requirements. Today, outdoor galvanized lamp pole factory Tianxiang will explain in detail the implementation standards for HDG street light poles, zinc coating thickness parameters for different wall thicknesses, and selection specifications for coastal and inland scenes, helping you avoid the pitfalls of thin coatings and non-standard materials.
I. General Implementation Standards for HDG Street Light Poles
As a core material for municipal lighting and road engineering, the zinc coating of HDG street light poles is crucial in determining rust and corrosion prevention and service life. Domestic projects generally follow the national standard GB/T 13912-2022 “Metallic Coatings – Technical Requirements and Test Methods for Hot-dip Galvanized Coatings of Steel Components”. Meanwhile, municipal and foreign trade export projects will refer to relevant ISO international galvanizing standards.
The standard clearly requires that the entire steel lighting pole adopt a whole-body hot-dip galvanizing process, prohibiting only surface spraying or partial galvanizing treatment. After pickling, rust removal, and fluxing, the steel substrate is immersed in high-temperature zinc bath to form a metallurgically bonded zinc layer. This layer has strong adhesion and is not easily peeled off, making it suitable for complex outdoor environments such as open fields, coastal areas, and humid, saline-alkali areas. It is the fundamental guarantee for the corrosion protection of street light poles.
II. Thickness Classification Requirements for Hot-Dip Galvanized Layer
1. Thickness Standards Based on Pole Wall Thickness
- Wall thickness < 4mm: Average zinc layer thickness not less than 55μm, with a minimum local thickness not less than 45μm. Mostly used for small courtyard poles and simple 3-5 meter street light poles.
- Wall thickness 4mm～6mm: Average zinc layer thickness not less than 70μm, with a minimum local thickness of 55μm. For 6-10 meter conventional road street light pole.
- Wall Thickness > 6mm: Average Zinc Coating not less than 85μm with a local minimum of 70μm. Applicable to high mast light above 12 meters, municipal main road, highway light poles.
2. Increasing Demand in Various Application Scenarios
Normal urban and rural roads: The national standard thickness is enough, and the service life is 15-20 years.
Coastal salt spray areas, chemical industrial parks, low-lying humid areas: the hot-dip galvanized coating should be thickened to more than 100μm in total thickness to enhance its resistance to salt spray and acid/alkali corrosion and slow down the oxidation and rusting of the zinc coating.
III. Acceptance of Quality of Zinc Coating—Minimum Requirements
1. Appearance Quality
Uniform and smooth surface, no incomplete galvanizing, bubbles, peeling, nodules and black spots. Welds, ports and flanges shall be free of dead corners and incomplete galvanizing.
2. Adhesion Standard
The zinc coating shall not crack or peel during hammer impact and cross-cut testing, and shall be firmly bonded to the steel substrate.
3. Testing Method
Multi-point sampling inspection using a zinc coating thickness gauge. The upper, middle, and lower sections of the pole and the flange base must all meet the standard. If any sampling fails, the entire batch must be re-inspected and reworked.
The thickness of the hot-dip galvanized layer directly determines the outdoor service life of steel lighting poles. Both engineering procurement and manufacturer customization must strictly match the corresponding galvanized thickness according to the national standard wall thickness. Outdoor galvanized lamp pole factory Tianxiang refuses non-standard thin galvanization to ensure the long-term stable use of lighting projects.
Post time: May-13-2026
