EN ISO 7686 Plastic Pipes and Fittings - Determination of Opacity

Material Testing

EN ISO 7686 Plastic Pipes and Fittings - Determination of Opacity

EUROLAB laboratory provides testing and compliance services within the scope of EN ISO 7686 standard. The EN 7686 standard specifies a method for determining the opacity of plastic pipes and fittings. A pipe or fitting used for water supply that is exposed to visible light during service must be sufficiently opaque to prevent algae growth.

EN ISO 7686 Plastic Pipes and Fittings - Determination of Opacity

The scattered and non-scattered light energy passing through a test piece cut from a tube or fitting at a wavelength of 540 nm to 560 nm is measured and expressed as a percentage of the light energy incident on the test piece.

The photoelectric cell is used such that the response of the readout or recording device is a linear function of light intensity from the maximum intensity Im to at least 0,01 Im. The detector should be mounted at right angles to the optical axis to ensure that all light passing through the sample is measured. An integrated sphere can be used to facilitate measurements. The incident beam will be centered at the inlet and will pass along the diameter of the sphere.

If an integrated sphere is used, the inner surface should have a white, diffusely reflective surface with greater than 70% reflectivity. The sphere must contain partitions so that neither the incident luminous flux nor the radiation through the test piece strikes the detector directly.

Adjustable power arc or incandescent lamp with light intensity constant up to ± 1%. A filter or other means shall be provided to limit the spectrum of light to a wavelength of 540 nm to 560 nm, unless the relevant standard specifies otherwise.

Aperture and optical lenses are tested with an apparatus whose width is adjusted to the size of the test piece, adjusted to obtain a parallel-sided and symmetrical incident beam that directs all light onto it, and is small enough to detect all light.

A rectangular flash of light on the axis of the test piece is preferred. It is recommended that the width of the light beam does not extend more than 0,25 to 0,3 times the outside diameter of the test piece to avoid light leakage around the lateral circumference of the test piece. The maximum size of the light beam should not be more than 0,5 to 0,7 times the diameter of the instrument inlet port.

The thinnest wall product in a manufacturer's range will be tested. Get a suitable length of pipe or fitting to be tested. Cut into four strips evenly spaced around the perimeter. If it is difficult to meet the recommendation for the width of the light beam when used for measuring small diameter pipe, the test piece may be straightened provided there is no significant change in thickness.

EUROLAB, with its more than 25 years of experience, state-of-the-art accredited laboratories and expert team, helps you get precise and fast results. Do not hesitate to contact our laboratory for your testing and certification requests.

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