| Number of Stacks | Measurement | Use of Test Tube | |
| Yes | No | ||
| 1 | Time to peak formaldehyde levels (min) | 28.5 ± 4.2 | 22.5 ± 2.5 |
|
| Peak formaldehyde levels (mg/L) | 0.4 ± 0.0 | 0.5 ± 0.0 |
|
| Time to reach above PEL1 | 0.0 ± 0.0 | 0.0 ± 0.0 |
|
| Time above PEL | 0.0 ± 0.0 | 0.0 ± 0.0 |
|
| Time back to base | 52.0 ± 3.3 | 49.3 ± 3.2 |
| 3 | Time to peak formaldehyde levels | 25.0 ± 2.7 | 25.3 ± 2.3 |
|
| Peak formaldehyde levels | 1.2 ± 0.1 | 1.0 ± 0.1 |
|
| Time to reach above PEL | 16.2 ± 1.9 | 12.5 ± 4.2 |
|
| Time above PEL | 19.2 ± 2.2 | 12.3 ± 4.1 |
|
| Time back to base | 62.0 ± 3.4 | 62.5 ± 0.8 |
| 5 | Time to peak formaldehyde levels | 24.5 ± 2.8 | 25.7 ± 2.2 |
|
| Peak formaldehyde levels | 1.6 ± 0.2 | 1.5 ± 0.2 |
|
| Time to reach above PEL | 14.0 ± 1.4 | 14.0 ± 2.4 |
|
| Time above PEL | 27.2 ± 2.7 | 24.2 ± 3.8 |
|
| Time back to base | 77.3 ± 14.1 | 84.7 ± 5.1 |