Teijin para-aramid fabric protects structures from airborne volcanic fragments

Designed specifically for use in Japan and other volcano-prone regions, the para-aramids protect structures from fragments as large as 100 mm in diameter.

Teijin Ltd. (Tokyo, Japan) reports that it has developed two new fabrics of Twaron and Technora para-aramid fibers to protect facilities such as lodges and evacuation shelters from airborne volcanic fragments measuring as much as about 100 mm in diameter.

The new fabrics are designed and produced in accordance with the Japanese Cabinet Office’s new regulations for strengthening evacuation facilities located near volcanos. The Ministry of the Environment is now using the fabrics to refurbish the roof of the Ebino Eco Museum Center in Kirishima-Kinkowan National Park on the island of Kyushu in southern Japan.

Teijin developed its new Twaron and Technora para-aramid-fiber fabrics in consultation with the Cabinet Office, the National Defense Academy, the Mount Fuji Research Institute of the Yamanashi prefectural government. In simulation tests held at a National Defense Academy facility in September 2015, the fabrics demonstrated their capacity to withstand fist-sized airborne fragments similar to those produced during the September 2014 eruption of Mt. Ontake, located 200 km west of Tokyo.

Teijin says Twaron offers six times more tensile strength than steel of the same weight, as well as superior heat resistance and elastic modulus. Technora, says Teijin, boasts even greater tensile strength and resistance to impact, fatigue and chemicals.

The choice of which para-aramid fiber to use depends on the envisioned level of protection required for each facility, based on a specific volcano’s activity level, altitude and local weather patterns. Teijin will focus marketing activities on local municipalities and private enterprises in areas prone to volcanic activity, with sales expected to reach 50,000m2 by the fiscal year ending in March 2017.

Protecting evacuation facilities and other structures from large airborne fragments is an important issue in Japan, one of the world's more active volcanic regions. While materials such as reinforced concrete and steel offer required levels of strength and durability, transporting heavy materials and large equipment to highlands can lengthen the construction period and raise construction costs. The deteriorating effect of severe weather on steel is another problem.