TPP Thermal Protective Performance Test Analysis
2016-11-21 08:52 | writer: admin
Thermal Protective Performance, namely TPP value is a kind of thermal protective capability of the fabric for the combined effects of thermal radiation and convection, this TPP value can reflect directly the thermal protective properties of the sample.
This test method is to placed the testing sample horizontally above the heat source, the heat source occurs in two different forms (convection and radiation) within the predetermined distance from the heat source, the copper sheet heat flow meter on the other side of the testing sample can measure the temperature of the back surface of the sample, with the copper heat flow meter on the back of the sample to measure the temperature rise curve, then contrast with the Stoll standard curve and obtain the second degree burn time t2, and then multiply t2 by exposure heat q, you can get the TPP value, the formula is TPP= t2 ×q . t2 refers to the time(s) needed to causing the second degree burn; q is convection and radiative heat flux which was preset by the TPP value system, the units is kW/ m.
The more larger of the TPP value, the more better of the fabric’s thermal protective property, namely the thermal insulation property is good. Otherwise, the thermal insulation property is bad. This method linked the material’s thermal protective property with human feelings and can predict the actual results of the clothing in the application. It has now been listed as common test methods.
The fabric’s thickness, density and permeability has significant impact on the TPP value. The more heavy fabric, the more fiber contained, the more difficult the heat through the fabric, so need long time to reach the grade II burn; There is obvious negative correlation between the fabric permeability and TPP value, namely the better permeability of the fabric, the more easily the radiant heat through the fabric. There is no significant correlation between the fabric density and TPP value.
In the study of the heat protective clothing’s property, we should not only pay attention to the comprehensiveness of the thermal protective clothing performance, namely the heat protective clothing should along with good thermal protective performance, comfort and wearability performance, but also put particular emphasis on the performance according to different wearing purpose. We should increase or enhance the requirements of certain performance, so that the performance of the thermal protective clothing tends to be more comprehensive and rational.