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The formaldehyde emission test cycle in a 1m³environmental chamber refers to the time period required for a material sample to reach a stable formaldehyde emission level by placing it in a 1m³climate chamber under controlled conditions of constant temperature,humidity,and airflow.This is achieved through periodic sampling and analysis.
The length of this cycle depends on factors such as material type,standard requirements,and data stability assessment.Generally,however,the typical test cycle ranges from 3 to 28 days.Stable state data usually appears after day 3,with most materials reaching equilibrium between 7 and 28 days.
I.Standard Testing Cycle(Common Standard Reference)
According to commonly used formaldehyde emission testing standards in China and internationally,the testing cycle for the 1m³environmental chamber method is generally as follows:
1.GB/T 17657-2013(China)
•Test Environment:Temperature 23±1°C,Relative Humidity 45%±5%,Air Exchange Rate 1 time/h
•Test Duration:Usually at least 7 days,recommended 14~28 days,until formaldehyde concentration reaches a stable state.
•Sampling time points:Generally,day 1(24 hours),day 3,day 7,day 14,day 28,etc.
•Stability determination:When the change in several consecutive sampling data is less than 5%,it can be considered to have reached stability,and the average value is taken as the final release amount.
2.GB 18580-2017(China,Formaldehyde Limit Standard for Wood-based Panels)
•Formaldehyde emission from wood-based panels is tested using the 1m³environmental chamber method(or desiccator method,perforation extraction method).
•The environmental chamber method is an arbitration method;the testing period is typically≥28 days to obtain stable emission data.
•In practice,many companies or laboratories will sample on days 3,7,14,and 28 to observe trends.
3.GB/T 39600-2021(China,Formaldehyde Emission Classification of Wood-based Panels:E1,E0,ENF)
•Clearly specifies the use of the 1m³climate chamber method,with a testing cycle typically of 28 days.
•Classification based on formaldehyde concentration under steady-state conditions:
•ENF grade≤0.025 mg/m³
•E0 grade≤0.050 mg/m³
•E1 grade≤0.124 mg/m³
4.ISO 12460-1(International Standard,Climate Chamber Method)
•Similar to GB/T 17657,the test cycle is generally around 28 days.
•The final evaluation is based on the time when formaldehyde release reaches a stable state(usually between day 14 and 28).
5.ASTM D6007/EN 717-1(American/European Standard)
•Also uses the climate chamber method;testing time is typically 1-4 weeks.
•Similar sampling intervals;focus on steady-state data.
II.Key node in the testing cycle(taking a 28-day test as an example)
Time Point | Description |
Day 1(24 hours) | Initial release,data is usually high;used to observe short-term release behavior but not for final evaluation. |
Day 3 | Begins to enter a relatively stable release period;can be used for preliminary assessment. |
Day 7 | Release of most materials starts to level off;trends can be determined for some materials. |
Day 14 | Release amount further stabilizes;many standards recommend measuring at least up to Day 14. |
Day 28 | The vast majority of materials reach a"stable release state";commonly used as the final evaluation point. |
>✅Definition of"stable state":If the formaldehyde concentration test results differ by no more than 5%in multiple consecutive tests(e.g.,more than 3 times),the formaldehyde release is considered to have reached equilibrium,and the concentration at this point is used to calculate the final release amount.
III.Why is the testing cycle so long?
The 1m³environmental chamber method has a long testing cycle(especially requiring approximately 28 days to reach a stable state)because:
1.Simulating a real environment:This method tests in a mild environment close to actual living conditions,unlike some rapid testing methods(such as the desiccator method and the perforation method),which are more intense.Therefore,the release process is slower and more realistic.
2.Formaldehyde release is a long-term process:Especially for composite materials such as engineered wood products,formaldehyde is not released all at once,but gradually over time and with environmental changes,initially quickly,then slowly,eventually reaching equilibrium.
3.High data accuracy is required:Only data that has reached a stable state can truly reflect the long-term formaldehyde release level of the material,used for environmental rating assessments or product compliance determinations.
IV.Differences in testing cycles for different materials
Material Type | Typical Test Period | Time to Reach Stability |
Engineered Wood(Plywood,Particleboard,MDF) | 28 days(recommended) | Day 14–28 |
Finished Furniture | 28 days | Day 21–28 |
Flooring(Laminate,Engineered) | 28 days | Day 14–28 |
Automotive Interior Materials | 14–28 days | Day 14–21 |
Textiles/Upholstery Materials | 7–14 days(depending on situation) | Day 7–14 |
V.Summary:Overview of Formaldehyde Emission Testing Cycle in a 1m³Environmental Chamber
Item | Description |
Typical Test Period | 7–28 days(in most cases,28 days) |
Sampling Time Points | Day 1(24 h),Day 3,Day 7,Day 14,Day 28(common) |
Stability Determination | Formaldehyde concentration changes≤5%over multiple measurements,usually occurs between Day 14–28 |
Basis for Final Result | Indoor formaldehyde concentration under stable conditions→used to calculate material emission(mg/m³or mg/(m²·h)) |
Standards Referenced | Standards such as GB/T 17657,GB 18580,GB/T 39600,ISO 12460-1 recommend or require a 28-day test |
✅Tips:
•If used for product launch,environmental certification,or classification(e.g.,E1/E0/ENF),testing must be conducted until a"stable state"(usually 28 days).
•If used only for internal quality control or preliminary screening,testing for 3-7 days is acceptable,but this data is for reference only.
•The 1m³environmental chamber method is the formaldehyde release testing method that most closely approximates the real-world usage environment.Although it takes longer,the results are authoritative and reliable
