Still, because of the impregnation method adopted and of a limited scope of strength tests, the method as described in the standard  does not always disclose the real impregnation effect.
An analysis of test results (tests made at the Zaklad Mechaniki Stosowanej Szkoly Glownej Sluzby Pozarniczej--the Applied Mechanics Department of the Main School of Fire Service) was made in order to clear the effect of fire-protection impregnation with salt-containing agents by a vacuum-and-pressure method.
Analysis of the knowledge regarding the impregnation effect on wood strength
More than a half of papers on fire-protection wood impregnation was devoted to the effect of impregnation for the flammability, inflammability, and carbonisation rate.
* Almost all researchers indicate significant and different effects of the impregnation on wood strength.
The test objective was to determine the vacuum-and-pressure method (with a salt-containing agent) influence on wood strength under normal conditions, and when exposed to high temperatures in the course of impregnation treatment.
A 20% solution of a fire-protection impregnation agent commonly used in Poland was applied for tests.
Ted Dawson, general manager of Industrial Impregnations
, said: "Having formed a very productive working partnership with Ultraseal, we are delighted that the parent company has been ultimately successful with the acquisition."