BS EN 717-1-2004 pdf download.Wood-based panels Determination of formaldehyde release Part 1: Formaldehyde emission by the chamber method.
Air-tightness shall be checked regularly, either by pressure drop measurements or by comparison of simultaneous
measurement of flow rates at the inlet and the outlet ports, or by measuring tracer gas dilution.
The test chamber is considered sufficiently air-tight if at least one of the following requirements is fulfilled:
— the air leakage is less than 10 2 x chamber volume per minute at an overpressure of 1 000 Pa;
— the inlet and outlet air flow differ by less than 2 %;
— the tracer gas dilution is less than 0,05/h.
8.2.3 Temperature and relative humidity control system
The temperature shall be controlled either by placing the test chamber within a location controlled to the appropriate temperature, or by controlling the temperature within the chamber.
In the latter case, the chamber walls shall be insulated effectively to avoid condensation of moisture on their inner surface.
Control of relative humidity shall be made either by external humidity control of the clean air supply, or internal humidity control of the air within the chamber. In the latter case, precautions shall be taken to avoid condensation, or spray of water, inside the chamber.
Temperature and relative humidity shall be monitored either continuously, or frequently, and independently of the air conditioning system. Sensors shall be placed in a representative position inside the chamber.
After loading the chamber, any Initial deviations of temperature and relative humidity due to ambient air and unconditioned test pieces shall be recorded.
8.2.4 Air exchange
The clean and conditioned air supply to the chamber shall either be monitored continuously, or frequently. Suitable methods are specified in Annex A.
The air exchange rate shall not vary by more than 0,05 exchanges of air per hour.
The effective air exchange rate shall be regularly checked, by using either a calibrated gas meter, or the tracer gas
procedure described in Annex B.
8.2.5 AIr velocity in the chamber
Prior to testing. the air velocity In the test chamber loaded with test pieces shall be set to a value between 0,1 m/s and 0,3 mIs, measured at representative positions not more than 20 mm from the surface of the test pieces.
8.4.2 Large chambers (see A.1)
Edge sealing shall not be done for the 1 m x 2 m test pieces tested in large chambers ( 12 m3). The perimeter. i. e the length of open (unsealed) edges U for 1 m x 2 m pieces is 6 m and the surface area A is 4 m2. Thus the ratio of U/A is 1,5 rn/rn2
8.4.3 Small chambers (see A.2 and A.3)
In order to obtain the same ratio of U/A = 1.5 m/m2 for smaller test pieces in small chambers, partial edge sealing is necessary. This sealing should be done using self-adhesive aluminium tape.
NOTE The length of edges to be sealed is given in A.2.3 for I m3 chambers and in A.3.3 for 0,225 m3 chambers.
8.5 Loading and starting procedure
Place the test pieces in the test ciamber. They shall be vertical and approximately in the centre of the chamber, with their surfaces parallel to the direction of the air flow, and separated by not less than 200 mm (see Figures A.1 to A,5 and A.7). The first air sampling shall be made not less than 3 h after loading the chamber and starting the test procedure.
8.6 Air sampling and analysis
Add at least 25 ml of water to each of the two gas washing bottles and connect them to the apparatus (see 6.2 and Figure 1). Sample the air from the chamber periodically by passing a minimum of 120 I, at a rate of approximately 2 1/mm, through the gas washing bottles. Pipette 10 ml of each of the absorption solutions into a 50 ml flask and add 10 ml acetylacetone solution (see 5.2) and 10 ml of ammonium acetate solution (see 5.3). Stopper the flasks and determine the formaldehyde content of the solutions according to Clause 9.
NOTE The volume of air to be sampled depends on its formaldehyde concentration, With photometric determination the procedure described above is suitable for concentrations higher than 0,005 rnglm3. For determination of lower concentrations, the volume of the sampled air should be increased andlor the volume of the air sample solution reduced. The sensitivity of the analysis can also be increased by using a fluonmetric determination of the reaction product (diacetyldihydrolutidine) instead of a photometric determination.BS EN 717-1-2004 pdf download.