Sampling

The following sampling systems are available at the GSA Schadstoffanalytik  for the sampling of wood dust:

  • SG10-2 with GSP3.5 (personal sampling)   
  • SG5100 ex with GSP3.5 (personal sampling)   
  • PM4-2 with total dust head (stationary sampling)
  • VC25-2 with total dust head (stationary sampling) 

Personal sampling is usually performed with the GSA measuring devices SG10-2 and GSP3.5 or GSP10.

The air loaded with dust is sucked in with a battery-operated pump (SG-10-2) with a volume flow of 3.5 l/min. We recommend a measurement duration of 2.5h with the GSP3.5 to be able to reach a volume of 0.53 m³ or 2 h with the GSP10 to reach a volume of 1.2 m³ so that 1/10 of the limit value (2 mg/m³) can be detected. The air loaded with E-dust flows through a membrane filter, a binder-free glass with fibre filter 37 mm diameter, on which the dust is separated.

Site-specific sampling is carried out by means of a volume flow-controlled sampling device with IFA E-dust sampling system (PM4-2) with a volume flow of 4 m³/h or with the IFA E-dust sampling system (VC25-2) with a volume flow of 22.5 m³/h. We recommend a measurement duration of 2 h.

As filter medium a binder-free glass fibre filter with a diameter of 70 mm or a binder-free glass fibre filter with a diameter of 150 mm weighed under defined conditions, temperature and humidity, is used.

 

Analysis

  • Electronic analytical balance (Mettler Toledo XPR 105 with ionisation module) 
  • Hydrothermograph (Testo/ testo Saveris 2)

 

Preparation of filters for E-dust / wood dust (wood processing companies)

The empty weight of the filters must be determined before sampling.

The filters are laid out for 48 hours in the weighing area and a relative humidity of 40 % – 55 % with temperature of 22 °C – 28 °C. This storage is called conditioning. After conditioning the filters are weighed and the results are recorded.

 

Analytical determination for E-dust / wood dust (wood processing companies)

The loaded filters are laid out for 48 hours in the weighing area, at a relative humidity of 40 % – 55 % and a temperature of 22 °C – 28 °C. After conditioning, the filters are weighed. The blind filters are to be treated in the same manner.

The mass of the E-dust is determined by differential weighing (weighing of the conditioned filters before and after sampling).

 

Preparation of the filters for the determination of the percentage of wood dust

The filters must first be annealed for 2 h at 550 °C in the oven. Then the filters are laid out for
48 hours in the weighing area, at a relative humidity of 40 % – 55 % and temperature of 22 °C – 28 °C. After conditioning the filters are weighed and the results are recorded.

 

Analytical determination for E-dust / wood dust (wood processing companies)

The loaded filters are laid out for 48 hours in weighing area at relative humidity of 40 % – 55 % and a temperature of 22 °C – 28 °C. After conditioning, the filters are weighed. The blind filters are to be treated in an identical manner.

Afterwards, the filters are annealed again for 2 h at 550 °C in the oven in order to be able to determine the ashable fraction after conditioning again for 48 h, at the relative humidity of
40 % – 55 % and a temperature of 22 °C – 28 °C, and weighing again. The percentage of wood dust is determined from the results obtained.

The determination limit for the 37 mm diameter binder-free glass fibre filter is 0.1 mg. For the
70 mm diameter with binder-free glass fibre filter is the determination limit 0.2 mg and for the 150 mm diameter binder-free glass fibre filter 0.3 mg absolute.

 

Limit value

The workplace limit value for hardwood dust is 2 mg/m³ in E-dust. In the case of a mixture of hardwood dust with other wood dusts, the workplace limit value for hardwood dust applies to all wood dusts contained in the mixture.

Appendix 1 of TRGS 906 lists the types of wood that are considered hardwoods in the scope of TRGS 906.

Wood dust, except hardwood dust, is classified as carcinogenic according to TRGS 905. Currently, there are neither acceptance nor tolerance values for wood dust in TRGS 910. Therefore, the assessment standard of 2.0 mg/m³ E-dust specified in TRGS 553 can be used temporarily.

Preparation sample carrier wood dust
Scale