About SEKI KOJI
About テクノフレックス
About 建築設備と配管工事
About fire
About Fire fighting equipment
About sprinkler
About sprinkler system
About joint(tool)
About internal pressure
About elongation
About strength
About fatigue life
About sprinkler extinguishing system
About fatigue life
About Fire
About Electric and disaster preventive equipment,elevators,etc.
About スプリンクラー
About 巻き出し