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APC GAL Galvanized Pipes


Galvanized Pipes Coated with Extrude Polyethylene


Technical Specification – According to SI 5089

1. General
    This specification describes the requirements and characteristics of
    APC GAL galvanized pipes (galvanized pipes coated with blue extruded
    polyethylene). APC GAL pipes are externally coated using modern
    extrusion-coating technology. The pipes are designed for transportation
    of fluids at temperatures not higher than 80 ºC, and are suitable for laying
    underground, inside buildings and for use underwater. APC GAL
    galvanized pipes are manufactured according to Israeli Standard 1205.1
    requirements for domestic plumbing.



2. Materials and coating
2.1 Pipes and materials
      The pipes and materials used in preparation of the coating comply with
      their relevant standards and specifications as listed below:
      2.1.1 Pipes
               The pipes comply with requirements of Israeli Standard 103
               (standard B) or 593 (schedule 40).
      2.1.2 Materials
          a. Epoxy base material
              A special epoxy suitable for application on heated pipes which is
              cured by the heat of the pipe.
          b. Adhesive material
              A thermoplastic copolymer based on polyolefin resins with polar
              groups and used for adhesion of the coating to the pipe surface.
          c. Coating material
              High density polyethylene (HDPE) containing colors and stabilizers
              against oxidation and radiation.
2.2 Coating layers
      The pipe coating has three-bonded layers.
      2.2.1 Base layer - The foundation base layer of the coating is made of
               epoxy resin at thickness of 100 μ.
      2.2.2 Adhesive layer – The intermediate layer of material bonds
               between the base and outer layers.
      2.2.3 External layer – The external layer is of high density polyethylene
               (HDPE) stabilized and painted blue.
2.3 Coating process
      2.3.1 Preparation of pipe surface
               Prior to application of the coating, the pipe is cleaned of dirt, oil
               and rust. The surface is blasted by steel grits. (Note: The
               thickness of the zinc layer following cleaning is at least 30 μ).
      2.3.2 Pre-heating
               Prior to application of the coating the pipe is heated to the
               temperature recommended by the manufacturer.
      2.3.3 Base layer coating
               Immediately following the heating of the pipe, epoxy is sprayed
               onto the hot pipe.
      2.3.4 Protective layer coating
               Two layers are applied to the surface of the pipe using co-
               extrusion technology.
      2.3.5 Cooling
               After coating, the pipe is cooled with water.



3. Requirements and tests
3.1 Cleanliness level – The level of cleanliness is visually assessed.

3.2 Overall thickness of coating – The minimum overall thickness of the
      coating is 1.5mm.The thickness may be up to 10% less than the
      declared value on condition that the thinnest area is not more than 5cm,
      along the entire length of the pipe.

3.3 Coating continuity – The coating should be continuous (without any
      holes). The coating is considered continuous if no faults are found in
      a Holiday Detector test at a voltage of 10kv along every millimeter of
      length.

3.4 Bond strength – Not less than 24 hours from the time of manufacture,
      the average required strength (minimum) for separation of the coating
      from the pipe will be 80N/cm.

3.5 Impact resistance – A 25mm diameter ball-shaped weight is dropped
      on the coated area from a height of 1 meter. This exercise is repeated
      at ten points along the length of the pipe with intervals of at least 30mm
      between each point. The energy produced by this impact is 3.5J.

3.6 Penetration assessment – The penetration depth will not exceed
      0.2mm at a temperature of 23 ± 2ºC and 0.3mm at a temperature of
      50± 2ºC. In this test a piece of detached coating (maximum thickness of
      2cm) is loaded with 2.5kg round steel pin with a cross-section area of
      2.5mm2.

3.7 Elongation at breakpoint – In the test according to part 3of Israeli
      Standard 878, the elongation at breakpoint will be at least 300%.
      An A' class sample is tested (diagram 2 in Standard 878) at 25 mm/min.

3.8 Electrical resistance of coating – The coating resistance assessed
      following acclimatization of the sample over 100 days will not be less
      than 108Ωm².

3.9 Heat ageing – A coating sample (of at least 2mm thickness) is
      exposed to a temperature of 100ºC for 100 days. The melt flow
      rate (MFI) is then measured deviate more than 35% from its
      original value.

3.10 Light ageing – The MFR will not deviate more than 35% from its
        original value. A coating sample with a maximum thickness of 2mm
        is exposed to a filtered xenon beam while being doused with water.
        The MFR is measured at the end of the test.