The FHDM Flame-Retardant Timber Test Apparatus (Wood Crib Method) is a laboratory testing instrument engineered for evaluating the mass loss rate and flaming combustion time of flame-retardant treated timber. Designed in compliance with public safety standard GA/T 42.1 and aligning with international wood crib testing concepts (such as ASTM E160) and national building material standard GB/T 8625, this system provides accurate flammability assessments for pressure-impregnated timber over 20 mm in thickness.
Featuring a precision-controlled Bunsen burner assembly, digital countdown/count-up timing, high-accuracy temperature calibration (310 °C ± 10 °C), and a dedicated flame protection hood, the FHDM Wood Crib Flammability Tester allows quality control personnel, timber impregnation plants, and accredited fire testing laboratories to verify whether treated wood products meet regulatory flame-retardant classifications.
Applicable Standards & Test Regulations
This timber wood crib combustion tester enables certified laboratories to perform standardized burning behavior evaluations in accordance with key industry standards:
| Standard Code |
Standard Title & Scope |
Primary Application |
| GA/T 42.1 |
Test methods for burning behavior of flame-retardant timber — Part 1: Wood crib method |
Primary governing standard for testing mass loss rate and flaming combustion time of impregnated timber (>20 mm thickness) |
| GB/T 8625 |
Test method for flammability of building materials |
National evaluation of flammability and fire resistance classification for treated wood building elements |
| ASTM E160 |
Standard test method for combustible properties of treated wood by the crib test (Historical/Referenced) |
International benchmark methodology for evaluating combustible behavior of fire-retardant pressure-treated wood |
| GA/T 42.2 |
Test methods for burning behavior of flame-retardant timber — Heat release rate |
Complementary evaluation of heat release and burning dynamics for flame-retardant timber products |
Technical Specifications of FHDM Flame-Retardant Timber Apparatus
| Governing Test Standard |
GA/T 42.1 (Referencing ASTM E160 & GB/T 8625) |
| Target Material Specification |
Flame-retardant impregnated timber with thickness > 20 mm |
| Specimen Dimensions |
76 mm × 13 mm × 13 mm (Tolerance ±1 mm), 24 pieces per group (3 groups total) |
| Gas Heat Calibration Temp |
310 °C ± 10 °C (Measured at the top opening of the flame protection hood) |
| Flame Height & Ignition Timer |
Flame height approx. 250 mm; Auto countdown timer: 3 min ± 0.1 s |
| Combustible Gas Source |
Natural Gas or Liquefied Petroleum Gas (LPG) |
| Operating Power & Ambient Requirements |
AC 220V ± 10V; Ambient Temp: Room temp to 35 °C; Humidity ≤ 70% RH |
Specimen Preparation & Testing Procedure
Specimen Sampling & Conditioning:
- Sampling Strategy: Cut specimen strips 0.6 mm away from the longitudinal ends of the timber (or from the center toward both sides for timber under 1 m long). Extract two layers of 13 mm × 13 mm strips parallel along the thickness from top and bottom faces; length is cut to 76 mm. Discard central portion.
- Conditioning: Prior to testing, condition specimens at 23 °C ± 2 °C and (50 ± 5)% RH until constant mass is reached (mass difference ≤ 1% between two weighings 24 hours apart).
Step-by-Step Test Procedure:
- Weigh each group of conditioned specimens to an accuracy of 0.1 g.
- Stack 24 specimen pieces onto the holder in a 12-layer crisscross (well-shaped/crib) grid, 2 pieces per layer spaced 25 mm apart.
- Power on the unit and reset the Bunsen burner position. Ignite the gas and adjust the needle valve to set a flame height of approximately 250 mm.
- Move the burner beneath the flame hood to calibrate gas flow until the top opening temperature reaches 310 °C ± 10 °C, then retract burner.
- Place the loaded specimen holder onto the circular support inside the protection hood, close the observation window, and initiate the test.
- The burner automatically advances under the specimen to ignite it for a 3-minute countdown before automatically retracting.
- Observe and record the post-ignition flaming combustion time. When flaming ceases, stop the timer.
- After cooling to room temperature, collect all remaining specimen pieces along with any fallen debris and weigh to 0.1 g accuracy.
Criteria for Judging Flame-Retardant Timber
According to GA/T 42.1 specifications, timber tested under the wood crib method is classified as Flame-Retardant Timber when meeting the following dual requirements:
- Mass Loss Rate: Combustion mass loss rate must be ≤ 60%.
- Flaming Combustion Time: Flaming combustion duration after ignition source removal must be ≤ 6 min (360 seconds).
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