Handbook of Solvents - George Wypych - ChemTech - Ventech!

18.1 Measurement and estimation of solvents emission and odor 1205
About 10 % of the solvent remains in the varnish and it is emitted, depending on the
type of solvent and varnish, with variable rate on their way to the consumers and in their living
spaces.
According to the European Commission, the furniture industry alone used more than
185,000 tons of solvents/year in 1994. 15
Not all the VOCs enter the air, however, since remedial efforts, such as absorption and
solvent reclaim, after-burning of solvents, the use of bio-filters, result in emission reduction.
Nevertheless, it is still evident that limitation of solvents, VOCs, reduction in varnishes
and coatings may help in reducing emissions.
18.1.2.3 VOC emissions from emulsion paints
Although emulsion paints and plasters contain less than 2% VOCs these are produced in
such large quantities (3.5 Million t in 1995) 16 and applied over such an extensive surface
that 100,000 t of VOCs are emitted from these materials per year. These enter the environment
in an uncontrolled way.
Prior to an interior application of the coating, there is no VOC in room atmosphere,
unless sources already exist in the room. Then the load - from the beginning of the application
- increases very rapidly. After the application, the VOC concentration in the ambient air
decreases exponentially. If these emissions are to be monitored it is desirable to have methods
available to record VOC concentrations typical of emitting stages. 17
18.1.3 MEASURING OF VOC-CONTENT IN PAINTS AND VARNISHES
18.1.3.1 Definition of low-emissive coating materials
In order to limit the sources of solvent emission in ambient air in the most effective manner,
primary goal must be to reduce the VOC content in coating materials. In Germany, there is a
draft for the Varnishing Plant Regulation 18 - regulating the application of low-emissive varnishes,
which will require that coating materials must initially not contain more than 420 g/l
VOC. Four years after the introduction of the regulation this is reduced to 250 g/l VOC.
The “Jury Umweltzeichen” (Environmental Trade Mark), which, since 1999, rewards
certain products with the environmental trade mark goes even further: For flat, plain materials
(e.g., interior doors, panels, floors with varnished surfaces, pre-fabricated parquet) the
coating systems applied must not exceed the VOC content = max. 250 g/l. 19
Varnishing plants are exempt if they employ waste gas purification facilities corresponding
to the EU VOC Guideline. 20
The draft of the Varnishing Plant Regulation follows the US method according to
ASTM D 3960-121 in determining the VOC content.
18.1.3.2 Determination of the VOC content according to ASTM D 3960-1
ASTM D 3960-1 is the method used in the US to determine the VOC content of coating materials.
The VOC value is calculated as follows:
[] − []
[] []
mass of volatile components g mass of water g
VOC value [ g / l ] =
volume of varnish l −volume
of water l
[18.1.1]
For varnishes exclusively containing solvents, this formula results in high values. This
calculation is, however, of dubious value for water-containing varnishes. The unit g/l does