Proposed directive concerning testing for formaldehyde emissions

Section 1: Chamber conditions for testing

1.1 Test chamber operation

The test method set out in paragraph 12(1)(a) of the Formaldehyde Emissions from Composite Wood Products Regulations (the regulations) is referred to as the large chamber throughout this document, and the results represent a single chamber value.

The test method set out in paragraph 12(1)(b) of the regulations is referred to as the small chamber throughout this document, and the results represent the average of three tests.

The test methods referred to in paragraph 12(1)(c) of the regulations are referred to as small-scale chambers throughout this document, and the results represent the average of three tests.

1.2 Averaging of test results

The test results may be averaged when conducting testing using a small chamber or a small-scale chamber for the purposes of sections 10 and 12 of the regulations.  In order to perform this averaging, a composite wood panel or laminated product is divided into three separate specimens representing evenly distributed portions of the entire panel or product. Three separate composite wood panels or laminated products are tested separately. The test results are averaged into one data point for the three composite wood panels or laminated products that those specimens represent.

Section 2: Equivalence of the large chamber and the small chamber methods

2.1 Establishing equivalence

For the purposes of subsection 10(3) of the regulations, when equivalence is established by an accredited laboratory between a small chamber and a large chamber, all small chambers can be considered to demonstrate equivalence.

To establish equivalence of testing methods pursuant to subsection 10(3) of the regulations, at least five sample sets must be used.

2.2 Calculations for establishing equivalence

For the purposes of subsection 10(3) of the regulations, manufacturers of composite wood panels or laminated products must ensure that equivalence between the results from the large chamber and the small chamber is demonstrated within the following ranges of formaldehyde emissions, unless they only manufacture panels or products in the lower range:

  • from 0 to 0.05 parts per million
  • from greater than 0.05 to 0.15 parts per million

A minimum of five specimens in each of the above formaldehyde concentration ranges must be tested using the large chamber and small chamber methods. This must represent a minimum of ten comparison specimen sets. If the manufacturer only manufactures composite wood panels or laminated products in the lower emission range, equivalence may be demonstrated only in that one emission range. The manufacturer is then restricted to only manufacturing panels or products within that one emission range.

For the large chamber method, each comparison sample must consist of the result of testing composite wood panels or laminated products, using the applicable loading factor specified in Table 1 of this document, from similar composite wood panels or laminated products of the same product type tested by the small chamber method.

For the small chamber method, each comparison sample must consist of testing specimens representing portions of composite wood panels or laminated products using Q/A ratio specified in Table 1 of this document from similar composite wood panels or laminated products tested using the large chamber method.

Arithmetic mean, ‘X’ and the standard deviation, ‘S’, of the difference of all paired results from the large and small chambers, must be calculated:

equation 1
Long description for equation 1

X equals the summation of Di divided by n for ith number of data sets, where i ranges from 1 to n.

equation 2
Long description of equation 2

S equals the square root of the summation of the square of the difference between Di and X, divided by n minus 1 for ith number of data sets, where i ranges from 1 to n.

where:

“n” is equal to the number of paired results,

“Di is the difference between the results from the large chamber and small chamber methods, for the nth data set, where “i” ranges from 1 to “n”.

The small chamber method is considered equivalent to the large chamber method if the following formula applies:

equation 3
Long description of equation 3

X plus 0.88 multiplied by S is less than or equal to C.

where:

“C” is less or equal to 0.026 for the low-emitting range of composite wood panels or laminated products set out in (i); and

“C” is less than or equal to 0.038 for the high-emitting range of composite wood panels or laminated products, set out in (ii).

Section 3: Quality control testing

3.1 Quality control test methods

When correlation has been established pursuant to subsection 12(6) of the regulations, the correlation can be considered demonstrated for all of the small-scale chambers within the same testing facility that use the same test method and are of a similar size and construction.

3.2 Quality control limit

For each test method used to perform the quality control testing set out in paragraph 12(1)(c) of the regulations, a manufacturer of composite wood panels or laminated products must establish a quality control limit (QCL) in consultation with an accredited laboratory. The QCL is the emission value for any chamber used for quality control testing in accordance with paragraph 12(1)(c) of the regulations, which is the correlative equivalent to the applicable limits set out in subsection 7(1) of the regulations based on the large chamber method. The QCL must be below the applicable limits set out in subsection 7(1) of the regulations.

The QCL is established by using a linear regression where the variables on the Y-axis are the results from the chamber that will be used for quality control testing, and the variables on the X-axis are the results from the large chamber. This linear regression is used to predict the point where the test method used for quality control testing generates results that are representative of the applicable limits set out in subsection 7(1) of the regulations when using the large chamber method.  

3.3 Reduced quality control testing for particleboard, medium-density fibreboard, and thin medium-density fibreboard

For the purposes of subsection 12(4) of the regulations, the manufacturer must maintain a 30 panel running average consisting of the average of the results of the 30 most recently sampled composite wood panels or laminated products.

The quality control testing for particleboard, medium-density fibreboard, or thin medium-density fibreboard may be reduced to one quality control test per 24-hour manufacturing period if the 30 panel running average remains two standard deviations below the designated QCL for the previous 60 consecutive calendar days or more.

The quality control testing for particleboard, medium-density fibreboard or thin medium-density fibreboard may be reduced to one quality control test per 48-hour manufacturing period if the 30 panel running average remains three standard deviations below the designated QCL for the previous 60 consecutive calendar days or more.

Section 4: Correlation of quality control testing methods

4.1 Requirements to establish correlation

For the purposes of subsection 12(6) of the regulations, correlation must be demonstrated at the outset of testing for a minimum of five sample sets. The manufacturer must work with an accredited laboratory to establish a quality control graph. The test results from the method used for quality control testing that is generated by the manufacturer is plotted on the Y-axis the emission test results from the large chamber or small chamber generated by an accredited laboratory is plotted on the X-axis.

4.2 Method of establishing correlation

For the purposes of subsection 12(6) of the regulations, the correlation is the Pearson Product Moment Correlation.

The minimum correlation coefficients are set out in Table 2 of this document, where:

  • ‘n’ is equal to the number of paired data sets from the quality control test method and the large chamber or small chamber
  • ‘r’ is the correlation coefficient

4.3 Circumstances when correlation must be re-established

For the purposes of subsection 12(6) of the regulations, a manufacturer of composite wood panels or laminated products must work with an accredited laboratory re-establish correlation if:

  • two consecutive emission tests in accordance with subsection 10(1) do not meet the emission limits set out in subsection 7(1) of the regulations, for the same product type
  • an emission test result generated in accordance with subsection 10(1) is compared to the quality control test result generated in accordance with  paragraph 12(1)(c) and does not fit the correlation established at the outset of testing    
  • there is a change in equipment, procedure or the qualification of testing personnel in a manner that affects limits of formaldehyde emissions

Section 5: Tables

Table 1: Formaldehyde chamber conditions
Test method Chamber type/size (m³) Length of time for conditioning Temperature for conditioning Relative humidity for conditioning Loading ratio (m²/m³) Temperature for test procedure Relative humidity for test procedure Air change rate for test procedure Q/A ratio* (m³/h air per m² test area)
Large chamber ≥22 m³ 7 days ± 3 h 24 °C ± 3 °C 50% ± 5% 0.43 hardwood plywood & particleboard
0.26 medium-density fibreboard & thin medium-density fibreboard
25 °C ± 1 °C 50% ± 4% 0.5 ± 0.05 h-1 -
Small chamber 0.02 to 1.0 m³ 7 days ± 3 h for emission testing
2 hours ± 15 minutes, or up to 7 days ± 3 h for quality control testing
24 °C ± 3 °C 50% ± 5% See Q/A ratio 25 °C ± 1 °C 50% ± 4% Varies. Allow for 3 full air changes or 15 min (whichever is greater). 1.172 hardwood plywood & particleboard
1.905 medium-density fibreboard & thin medium-density fibreboard

* Q/A ratio (m³/h air per m² test area). ‍Q/A ratio is the area-specific flow rate, m/h. It is the ratio of air flow through the chamber (Q, m³/h) to sample surface area (A, m²). For the small chamber, the test chamber Q/A ratio is set to achieve the same loading factor and air change rate as the large chamber.

Table 2: Minimum acceptable correlation coefficients (“r” values)
Degrees of freedom (n-2) “r” value
3 0.878
4 0.811
5 0.754
6 0.707
7 0.666
8 0.632
9 0.602
10 or more 0.576

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