VW PV 3341 Non-metallic Materials of Automotive Interior Trim - Determination of Emission of Organic Compounds

The standard “VW PV 3341 Non-metallic materials of automotive interior trim - Determination of emission of organic compounds” developed by the Volkswagen automobile company describes a procedure for determining the emission of organic compounds from non-metallic materials that directly or indirectly affect vehicle passenger compartments.

The emission potential is measured according to the sum of all values ​​provided by the emitted substances after gas chromatography analysis and flame ionization detection. Sample entry is made by blank analysis after conditioning at 120 degrees.

The requirements in this standard are specified as follows:

• Suitable locations for removing samples, applicable limit values ​​and any special procedural requirements are found on the relevant drawing or specification.
• If parts consist of a variety of materials, separate testing is required for each material.
• The sample should be transported and stored in a polyethylene bag with an aluminum liner.
• The sample should be prepared immediately after receipt of the goods or in a suitable condition. The time of collection and the time of sample removal should be kept in records.
• The sample is usually not conditioned. However, natural materials such as cotton, wood, leather and wool are exempt from this rule. Before weighing, these materials should be cut into pieces and dried for 24 hours on calcium chloride.
• The sample shall be removed from the material at the specified location along the entire cross-section of the sample. It shall then be cut into pieces weighing between 10 mg and 25 mg without increasing the temperature of the sample. A different type of preparation may be specified on the drawing or specification if necessary. This shall be stated when listing the results.
• The sample quantity depends on the size of the headspace bottle with a minimum volume of 5 ml. 10 g plus/minus 1000 g of sample material is weighed per 0,001 ml bottle volume (i.e., maximum weighing deviation 0,1 percent). Metal parts are removed before weighing.
• Paint, adhesives and similar organic materials adhering to metal parts are first mechanically removed and then weighed.
• Sample aliquots are weighed in a headspace bottle (minimum 3 bottles per sample). The bottle is sealed gas-tight using a teflon-coated septum facing the inside of the bottle.

Equipment used in the tests includes:

• Gas chromatograph for use with capillary columns with headspace sampling valve, flame ionization detector and computer/integrator.
• WCOT column with 100 percent polyethylene glycol separation phase, e.g. DB wax, carbowax (0,25 mm ID, 0,25 pm film thickness, 30 m length)
• Analytical balance (0,1 mg accuracy)
• Microliter syringe (5 μl sampling in glass body)

The measurement conditions in the standard are specified as follows:

• GC oven temperature program: 50 min isothermal at 3 degrees, heating to 12 degrees at 200 K/min, 200 min isothermal at 4 degrees
• Detector temperature: 250 degrees
• Split ratio: about 1:20
• Carrier gas: helium
• Average carrier gas velocity: 22 to 27 cm/s

The testing procedure consists of the following steps:

• Before measurement, the bottles are conditioned in the air above the sample for 120 hours plus/minus 1 minutes at 5 degrees plus/minus 5 degree to enrich the bottle with the substances contained in the sample, and the bottles are analyzed immediately afterwards.
• At least 3 samples are analyzed.
• The blank value is determined by calculating the average value of the signal values ​​from at least 3 measurements with empty bottles.
• The dosage must be the same and reproducible for all analyses of samples, blanks and calibration solutions.
• The separation column is heated to maximum temperature for at least 15 minutes once a week.

For quantitative determination of both total carbon emissions and the amount of certain individual substances, calibration characteristics are drawn according to the external standards method.

Acetone serves as the calibration substance for total carbon emission, the substances themselves are used for the individual substances. General calibration with 7 calibration solutions should be performed both after the installation of a new column and after each modification of the instrument. In addition, control calibration should be performed at least every 3 weeks with at least 4 solutions. All substances used during calibration must be of at least reagent grade quality.

Among the numerous tests, measurements, analyses and evaluations carried out by our organization for businesses in various sectors, our organization also provides testing services defined in the standard “VW PV 3341 Non-metallic materials of automotive interior trim - Determination of emission of organic compounds” with its trained and expert staff and advanced technological equipment.