When winter arrives, insulated boots, snow boots, and cold-protective safety footwear become essential.
The core capability of a qualified winter shoe lies in its ability to retain heat and resist cold. However, many people judge warmth simply by “trying them on” – but the industry has long established standardized, quantifiable testing procedures, with unified reference standards both in China and internationally.
I. Testing Standards
To objectively evaluate a shoe’s cold resistance, subjective feel is not enough. Clear standards are available:
- Chinese standard: GB/T 21284-2015 – the general testing basis for cold-resistant footwear in China
- International standard: ISO 20877:2011 – widely adopted for cold-resistant footwear testing overseas
The full testing procedure and required equipment are referenced from Clause 5.13 of ISO 20344:2011 Personal protective equipment – Test methods for footwear. The testing logic is fully aligned globally, and the procedure described below is applicable in laboratories worldwide.
II. Professional Testing Equipment
Cold resistance testing relies on specialized equipment, including:
- Cold resistance test chamber – a temperature-controlled ultra-low temperature freezer that maintains a stable environment of -17±2°C throughout the test, simulating extreme winter conditions
- Standard stainless steel weighting beads – uniformly sized (5 mm diameter), with a total weight of 4000±40 g, used to fill the shoe interior and simulate real wearing conditions
- High-precision temperature measuring device – equipped with miniature temperature sensors capable of accurately reading the insole temperature to ±0.5°C precision
III. Pre-Test Sample Conditioning
To avoid environmental temperature interference, shoes and steel beads must undergo standard conditioning before testing:
- Prepare at least 2 complete finished shoes as test samples
- Place shoes and steel beads together in a standard environment of 23±2°C and 50±5% relative humidity
- Allow to stabilize for at least 3 hours until both shoes and beads reach a stable temperature of approximately 23°C – eliminating measurement errors caused by temperature differences
IV. Sample Assembly
After conditioning, install the temperature sensor and seal the shoe opening – to best simulate actual wearing conditions:
- Secure the temperature sensor: Place the temperature probe on the insole/sock liner at the forefoot area (the weight-bearing zone), which best reflects actual foot temperature
- Load the steel beads: Pour all standard steel beads into the shoe
- Extend the shaft (if needed): If the boot shaft is too short, use closed-cell elastic foam (EVA/PE/PU) of ≥8 mm thickness to create an extension collar that fits the shoe opening. Joint gaps ≤3 mm, overlap area ≤20 mm to prevent heat loss
- Seal the shoe opening: Use a rigid foam plug of ≥25 mm thickness to close the shaft opening, secured with tape to prevent cold air ingress
- Recondition after assembly: Allow the assembled sample to rest for 3 hours until the shoe temperature returns to 23±2°C before starting the test
V. Cold Test Procedure and Result Interpretation
- Pre-start the cold test chamber and stabilize the internal temperature at -17±2°C
- Place the assembled shoe steadily on the test platform inside the chamber, close the chamber, and start timing
- After 30 minutes of exposure, read the temperature recorded by the sensor
- Calculate the temperature drop: subtract the 30-minute insole temperature from the initial 23°C – this temperature drop value is the core indicator of the shoe’s cold resistance performance
VI. Cold Resistance Pass/Fail Criteria
This limit is widely adopted as the acceptance criterion for snow boots and insulated footwear currently on the market: after 30 minutes of exposure at -17±2°C, the temperature drop inside the shoe must be ≤10°C to qualify as having adequate cold resistance. Simply put: the internal temperature can drop by no more than 10°C – the smaller the drop, the better the insulation.
VII. PFI’s Technical Support for Cold Resistance Testing
Many clients experience temperature drop >10°C when testing new samples, failing to meet national or international standards – leading to rework, order delays, and market non-compliance risks. To address these challenges, we offer full-process technical support:
- Pre-screening evaluation – avoiding large-scale rework
During the sample development stage, we can conduct simulated cold resistance testing in accordance with relevant standards – providing early temperature drop data and predicting whether the product will pass formal testing. This prevents non-compliance risks before mass production begins. - Pinpoint insulation weaknesses – providing corrective solutions
If the temperature drop exceeds the limit, our engineers will analyze the data to identify the root causes of heat loss – and provide targeted recommendations from raw material selection, structural optimization, and process improvement perspectives. - Retesting and mass production support
We offer post-improvement retesting to compare temperature drop data before and after optimization. For clients in mass production, we also assist in establishing in-house cold resistance testing standards and train QC personnel in testing methods and judgment criteria – ensuring consistent quality across production batches.
